Surgery Book MCQs - Quiz 1 (Chapters: 1-10)

A 42-year-old woman with a history of alcohol abuse is admitted to the intensive care unit with active bleeding from esophageal varices. The medication most useful for decreasing the risk of rebleeding, with the least side effects, is A. octreotide B. proton pump inhibitor C. beta-blocker D. vasopressin E. nitroglycerin

Answer: A Although proton pump inhibitors are useful for bleeding ulcers and are usually given to patients with variceal bleeds, they do not decrease the bleeding. Beta-blockers and nitrates help prevent recurrent bleeds but are dangerous while the patient is bleeding. Vasopressin, used for years to help treat variceal bleeding, is a nonspecifi c vasoconstrictor and thus is risky. Octreotide can decrease rebleeding with few side effects.

A 30-year-old man is in the hospital recovering from splenectomy for a ruptured spleen sustained in a motor vehicle collision. He has otherwise been healthy and was not taking medications prior to the injury. A temperature of 102°F is noted on the second postoperative day. Vital signs are BP 130/80 mm Hg, pulse 100/minute, and respirations 18/minute. His pain is moderately controlled with morphine using patient-controlled analgesia (PCA). Breath sounds are diminished at both bases, more so on the left. His abdomen is mildly distended, soft and tender near the incision. The incision appears to be healing without a problem. What is the most likely cause for his fever? A. Atelectasis and pulmonary infection B. Peritonitis C. Urinary tract infection D. Suppurative thrombophlebitis E. Cardiac contusion

Answer: A Early postoperative fever is usually the result of atelectasis and subsequent pulmonary infection (Table 8-6). In this scenario, because of the close proximity of the left hemidiaphragm to the spleen, an infi ltrate in the left lower lobe of the lung is a high probability. An adequately drained urinary tract in a young person seldom gives a high fever this early in the postoperative period. Although peritonitis from injury to a surrounding structure during the splenectomy (i.e., pancreas, stomach, or bowel) is a possibility, it is much less likely than a pulmonary source. Cardiac contusion does not elicit a febrile response

A 50-year-old man is started on IV heparin for a peripheral arterial thrombosis. Three days later, it is noted that his platelet count has dropped from 200 to 35. What is the next best step in management? A. Discontinue heparin and administer lepirudin B. Continue heparin and administer argatroban C. Discontinue heparin and administer aspirin D. Discontinue heparin and administer Coumadin E. Continue heparin and administer a platelet transfusion

Answer: A Heparin-induced thrombocytopenia (HIT) is a hypercoagulable state manifest by arterial and venous thromboses. HIT occurs as a result of antibody formation to heparin-platelet complexes and results in thrombocytopenia due to intravascular platelet activation and aggregation. There is no indication for platelet transfusion. It can occur due to administration of any type of heparin. Patients must be anticoagulated with an alternative agent such as argatroban, lepirudin, or danaparoid. In this setting, starting Coumadin without starting one of these alternative agents is contraindicated as the initiation of Coumadin therapy is associated with a transient hypercoagulable state.

A 65-year-old man is seen in the emergency department with a 5-day history of nausea and vomiting. He has been drinking only water for the last 2 days. His BP is 100/75 mm Hg with a heart rate of 105/minute. He has a distended abdomen with no bowel sounds but no signs of peritonitis. A diagnosis of a bowel obstruction is made after x-rays of the abdomen reveal distended loops of small bowel. Which of the following abnormalities would you expect to find in this patient? A. Na+—110 mEq/L, Cl−—90 mEq/L, K+—2.8 mEq/L, CO2—20 mEq/L B. Na+—150 mEq/L, Cl−—120mEq/L, K+—5.5 mEq/L, CO2—20 mEq/L C. Na+—140 mEq/L, Cl−—110 mEq/L, K+—4.0 mEq/L, CO2—26mEq/L D. Na+—120 mEq/L, Cl−—120 mEq/L, K+—5.5 mEq/L, CO2—18 mEq/L E. Na+—135 mEq/L, Cl−—105 mEq/L, K+—3.5 mEq/L, CO2—24 mEq/L

Answer: A In a patient with a bowel obstruction who begins vomiting, the initial acid-base abnormality would be a hypochloremic, hypokalemic metabolic alkalosis due to the loss of hydrogen ion, chloride, and potassium from the stomach. The bowel will continue to secrete fl uid into the small intestine, which will initially lead to hypovolemia that is compounded by the loss of gastric fl uid. This results in an increase in aldosterone, which will result in increased reabsorption of sodium and chloride from the kidney, but since the vomiting results in a loss of chloride, eventually a reduction in chloride in the renal tubule will result in absorption of bicarbonate with the sodium. The resulting alkalosis may be associated with a mild respiratory acidosis to compensate for the metabolic acidosis. As the fl uid sequestration in the small intestine increases, hypovolemia increases, which increases ADH and stimulates thirst. The kidneys reabsorb more water and sodium and the patient tries to drink but in this case only tolerates water. This results in an increase in water in relation to sodium in the extracellular fl uid (even though both are reduced compared to the normal state) and a hyponatremia occurs. Now the patient has a hyponatremic, hypokalemic, hypochloremic metabolic acidosis, which is compensated partly by a respiratory acidosis. As the hypovolemia progresses due to the sequestration of fl uid in the intestine and perhaps into the peritoneal cavity, the patient may develop a stage 2 shock state that results in a mild cellular acidosis, which eventually causes a metabolic acidemia superimposed on the metabolic alkalemia. Hence, the fi nal presenting electrolyte and acid-base abnormality seen on the electrolytes in this patient is a hyponatremic, hypokalemic, hypochloremic metabolic acidemia. The fi rst priority in the treatment of this condition is to correct the hypovolemia, in this case with normal saline since there is also a chloride defi cit, and add potassium to the fl uids since the patient has a profound potassium defi cit that may be slightly masked by a lower than normal pH. (See relation between acidosis and potassium in text.) Since the patient is stable without signs of peritonitis, there is time to correct the fl uid and electrolyte disorders before taking the patient to surgery. Failure to correct before surgery could result in multiple complications including a more profound hypotension and arrhythmias due to the low potassium. In general, correction of vascular volume takes precedence followed by correction of acid-base and potassium abnormalities and fi nally correction of any other fluid and electrolyte problems.

A 65-year-old man is severely injured in a dump truck rollover accident. He has sustained bilateral femur fractures, a pelvic fracture, and a pulmonary contusion. A pulmonary artery catheter is placed in order to guide you in the optimization of his hemodynamic status and guide his resuscitation. Correction of which current value will have the most dramatic impact on his oxygen delivery? A. Measured cardiac output of 2 L/minute B. Serum hemoglobin of 12 mg/dL C. Arterial PO2 of 82 mm Hg D. Arterial oxygen saturation of 93% E. Pulmonary capillary occlusive pressure of 10 mm Hg

Answer: A Oxygen delivery is delineated by the relationship O2D = (CO × CaO2 × 10). 10 is a factor to convert mL O2/100 mL blood to mL O2/L blood. The key components of the relationship are CO (measured cardiac output, which in turn is defi ned by the relationship CO = HR × stroke volume) and arterial oxygen content (CaO2, defi ned as CaO2 = 1.39 × Hgb × SaO2 + (PaO2 × 0.0031) ). Of the answers listed, the most deranged from baseline is a CO of 2L/minute (average adult normal values are 4.5 L/minute for women and 5 L/minute for men), and, given the mathematical relationship of the O2D equation, it will have the greatest impact on this value when corrected. The values given for hemoglobin (B), arterial oxygen saturation (C), and pulmonary artery occlusive pressure (E) are all near or within normal values. Even relatively dramatic changes in arterial PO2 will have a minimal impact on O2D given the correction factor of 0.0031 as delineated in the CaO2 equation (answer C).

A 22-year-old man is in the emergency department after a highspeed motor vehicle collision. He complains of back pain. He is alert and oriented and is breathing normally. His oxygen saturation is normal and hemodynamically stable. There are ecchymoses on the left chest. Chest x-ray shows fractures of the left fi rst and second ribs. The aortic knob is not clearly visible, and the mediastinum measures 10 cm. Further evaluation should include which of the following? A. Contrast-enhanced chest CT B. Repeat chest x-ray C. Diagnostic thoracoscopy D. Pericardial window E. Diagnostic mediastinoscopy

Answer: A The high-speed deceleration mechanism and chest x-ray fi ndings are highly concerning for blunt aortic injury (BAI), which is most effi ciently diagnosed by contrast-enhanced chest CT. Repeat chest x-ray would likely reveal the same fi ndings but would not establish the diagnosis. Thoracoscopy is useful for evaluating the pleural space, lungs, and diaphragm, but not the aorta and great vessels. Pericardial window may be utilized to diagnose hemopericardium in suspected penetrating cardiac trauma, but not aortic injury. Mediastinoscopy is used for evaluating lymph node status in lung cancer staging but has no role in trauma. (Taken from Thoracic Injury: Potentially Severe Injuries Detected During Secondary Survey).

A 28-year-old man is undergoing an operation for right inguinal hernia. The anesthesiologist notices that his end-tidal CO2 value rises abruptly, and the patient's jaw is stiff. The patient's temperature is 41°C, his heart rate is 130 beats/minute, and his blood pressure (BP) is 130/75 mm Hg. Which of the following abnormalities would be expected if a sample of his blood were tested at this point in the operation? A. Hyperkalemia B. Hypocalcemia C. Alkalosis D. Anemia E. Hypoalbuminemia

Answer: A This is a classic description of malignant hyperthermia. The typical electrolyte picture is that of rhabdomyolysis, with hyperkalemia, hypercalcemia, and acidosis. Malignant hyperthermia is not known to affect red cell mass or albumin levels. The patient should be given 100% oxygen, the operation should be stopped and the wound closed, and dantrolene should be administered.

A 40-year-old woman is admitted with a 3-day history of diarrhea. She has a history of chronic renal insufficiency due to diabetic nephropathy. She is mildly acidotic. Serum potassium is 6.8 mEq/L. An ECG shows peaked T waves. Which of the following is the most appropriate initial treatment of the hyperkalemia? A. Subcutaneous administration of 10 units of insulin plus 25 g of glucose over 5 minutes B. Administration of a bicarbonate infusion or by injecting 45 mEq sodium bicarbonate intravenously over 5 minutes C. Intravenous administration of sodium polystyrene sulfonate, a cation-exchange resin, to bind extracellular potassium D. Transferring the patient to a center with hemodialysis and peritoneal dialysis capability E. Rapid intravenous infusion of 50 mL of 10% calcium gluconate under continuous ECG monitoring

Answer: A Hyperkalemia <6 mEq/L or hyperkalemia without ECG abnormalities usually needs minimal intervention other than stopping any potassium infusion, deciding if this increase in potassium is due to a signifi cant metabolic acidosis (since the potassium will increase at least 0.3 mEq/L for every 0.1 decrease in pH), checking to make sure the increased potassium was due to hemolysis of the blood sample, and monitoring the cardiac rhythm. If the patient has ECG evidence of peaked T waves, then prompt administration of 25 g of glucose plus 10 units of insulin is recommended followed by hemodialysis if necessary. If the T waves are higher than the R wave or if there is widening of the QRS complex and a decrease in the P-wave amplitude, immediate treatment is indicated with either infusion of 10 mL of 10% calcium chloride over 10 minutes or 10 mL of calcium gluconate over 3 to 5 minutes. Calcium chloride freely dissociates upon infusion resulting in 13 mEq of free calcium, whereas calcium carbonate results in only 4 mEq of free calcium. The remainder of the calcium is released as the carbonate is metabolized. Intravenous infusion of 50 mEq or more of sodium bicarbonate over 20 minutes may also be used. The amount of bicarbonate infused is proportional to the degree of acidosis but is usually not used unless the pH is <7.20. Rapid increase in potassium such as occurs with sudden renal failure or rhabdomyolysis may be lethal if not diagnosed and treated quickly.

A 25-year-old man is seen in the emergency department because of a painful swollen forearm. Two days ago, he sustained a small laceration to his left forearm while clearing brush. It caused only minor discomfort until about 12 hours ago when the area around the laceration became more red and swollen. He has otherwise been healthy. He takes no medications. His temperature is 38°C. There is a 2-cm superfi cial laceration on the dorsum of his left forearm with 15-cm diameter surrounding erythema that is quite tender. The edges of the erythema were marked and 20 minutes later the erythema has extended another cm beyond the mark. The most likely causative organism is A. methicillin-resistant Staphylococcus aureus. B. β-Hemolytic Streptococcus A. C. Escherichia coli. D. Streptococcus faecalis. E. Candida albicans.

Answer: B Although cellulitis may be caused by any organism, the most likely early organism would be ß-hemolytic Streptococcus A. Methicillinresistant Staphylococcus aureus more commonly causes local infl ammation and pus formation. The other three species are rarely isolated from skin infections but more commonly are seen in infections involving the gastrointestinal tract

Two weeks following a severe motorcycle crash, a 25-year-old woman remains intubated in the surgical ICU. You are called to the bedside to evaluate a change in her condition. On evaluation, her vital signs include temperature of 39°C, heart rate of 110 beats/minute, respiratory rate of 22, blood pressure of 88/50, and arterial oxygen saturation of 96%. Her urine output has been 20 mL over the past 8 hours. On exam, she is in moderate distress and appears confused. She has crackles posteriorly in her left lung fields and her extremities are warm. A bronchoalveolar lavage is performed revealing Gram-negative rods. What is your diagnosis? A. Atelectasis B. Septic shock C. Systemic inflammatory response syndrome D. Allergic reaction to penicillin E. Pulmonary embolus

Answer: B Although infl ammation is a normal response to tissue injury, the patient in the above scenario is displaying evidence of a dysfunctional infl ammatory response. The derangements noted are too severe for atelectasis (answer A), which is associated with slight fever and normal blood pressure. Although allergic reactions (answer D) can be associated with cardiovascular collapse, there is no history of recent medication administration given. Pulmonary embolus (answer E) may present as tachycardia and hypotension but is typically also associated with hypoxia.To meet the definition of the systemic inflammatory response syndrome, or SIRS, a patient must have two or more of the following conditions: (1) temperature >38.5°C or <36°C; (2) heart rate >90 beats/minute; (3) respiratory rate >20 breaths/minute or PaCO2 < 32 Torr; and (4) total leukocyte count >12,000 cells/mm3 , <4000 cells/ mm3 , or >10% immature forms. Although the patient in the scenario meets these criteria (answer C), the additional presence of end-organ dysfunction (hypotension, oliguria) and infection (Gram-negative rods on bronchoalveolar lavage [BAL]) make the diagnosis of septic shock more appropriate (answer B).

A 53-year-old man sustains a severe traumatic brain injury after an assault. His GCS score is 6, and an intracranial pressure monitor is inserted. Vital signs are heart rate—92 beats/minute, blood pressure (BP)—152/88 mm Hg, mean arterial pressure—109 mm Hg, and respiratory rate—16/minute. His intracranial pressure is 32 mm Hg. The patient's cerebral perfusion pressure is A. 120 mm Hg. B. 77 mm Hg. C. 60 mm Hg. D. 56 mm Hg. E. 32 mm Hg.

Answer: B Cerebral perfusion pressure (CPP) is calculated by subtracting the intracranial pressure (ICP) from the mean arterial pressure (MAP). (Taken from Head Injury: Anatomy and Physiology).

A 55-year-old woman is scheduled for a craniotomy to remove a brain tumor. She has a history of hypertension and hypercholesterolemia, and she underwent coronary artery angioplasty with a stent placed 6 months ago. Current medications include enalapril, pravastatin, and clopidogrel. Which one of the following would most likely be prolonged? A. Activated partial thromboplastin time (APTT) B. Bleeding time C. Prothrombin time (PT) D. Thrombin time E. Activated clotting time (ACT)

Answer: B Clopidogrel is a platelet-inhibitor medication that is often used after the placement of intravascular stents to prevent thrombosis. Like aminopsalicylic acid (ASA), clopidogrel is nonreversible; therefore, it should be stopped 7 to 10 days before surgery if normal coagulation is required. Prolonged bleeding time is associated with platelet dysfunction. The APTT (intrinsic and common pathways), PT (extrinsic and common pathway), and thrombin time (formation of fi brin from fi brinogen) evaluate specifi c aspects of the coagulation cascade.

A 60-year-old woman is being evaluated for surgery to repair an abdominal aortic aneurysm under general anesthesia. She smoked a pack of cigarettes daily for 35 years, but quit 5 years ago when she had a myocardial infarction (MI) complicated by congestive heart failure. She still has occasional orthopnea. She also has hypercholesterolemia and hypertension. Which one of the following factors suggests the greatest risk for a cardiac complication following her surgery? A. History of cigarette smoking B. Congestive heart failure with orthopnea C. General anesthesia D. Hypertension E. Hypercholesterolemia

Answer: B General anesthesia does not itself increase risk of cardiac complications.The factors that do increase such risk include ischemic heart disease, congestive heart failure, chronic kidney disease, cerebrovascular disease, or high-risk operations such as major vascular surgery.

A 25-year-old man suffers burns to 40% total body surface area (TBSA) in an explosion at a natural gas drilling site. He requires emergent intubation and fl uid resuscitation. During his fi rst week of hospitalization, he undergoes a major operative procedure for excision and skin grafting. By the end of the third week in the hospital, his weight (which originally increased with resuscitation) has come back down, and he weighs 12 pounds less than before the injury. What is the most likely cause for his weight loss? A. Decreased nitrogen excretion and resulting catabolism B. Increased nitrogen excretion and resulting catabolism C. Protein malnutrition with respiratory muscle building D. Immune system building with increased risk of pneumonia and bacteremia E. Indirect calorimetry readings to support positive nitrogen balance

Answer: B In response to the increased metabolic demands of a major burn, skeletal muscle is broken down to provide an available energy substrate. This results in increased nitrogen excretion, and loss of lean body mass, which can exceed a half pound per day. Cardiac muscle and respiratory muscles are not immune from these effects, and as muscle wasting continues, both heart failure and respiratory failure can occur. Loss of as little as 15% lean body mass can lead to a fatal degree of inanition within a few weeks of injury. Section: Defi nitive Care of Burn Injuries. Subsection: Nutritional Support.

A 52-year-old man was admitted to the hospital with bilateral femur fractures and rib fractures following a motor vehicle crash. He developed a deep vein thrombosis involving the left femoral vein and was started on intravenous heparin 4 days after admission. His platelet count decreased and concern was raised for heparininduced thrombocytopenia. Which of the following would be the best alternative anticoagulant? A. Clopidogrel B. Argatroban C. Warfarin D. Enoxaparin E. Aspirin

Answer: B In this setting, any heparin product should be stopped immediately, including low molecular weight heparin, such as enoxaparin. Use of warfarin is appropriate in the long term but will not be effective immediately. Antiplatelet therapies, such as aspirin and clopidogrel, have no proven role as substitutes for anticoagulants. The best choice is argatroban, a direct thrombin inhibitor.

A 52-year-old man is in the clinic to discuss treatment of a newly diagnosed pancreatic cancer. He has no significant past medical history. He takes no medications. There is no evidence of metastatic disease, and the tumor is small and appears to be resectable by pancreaticoduodenectomy (Whipple procedure). Optimal treatment would also include adjuvant radiation therapy and chemotherapy. Informed consent for this patient is best defined as A. a form that can be used as a legal defense should a complication occur during the treatment of the patient's problem. B. a process in which the physician and patient discuss the risks and benefits of different approaches to the patient's problem. C. a process in which every possible complication of treatment is enumerated. D. a theoretical construct with little practical utility. E. a philosophical principle that applies to surgical procedures but not medication administration.

Answer: B Informed consent is a process in which the physician and patient discuss the risks and benefits of different approaches to the patient's problem. This includes discussion of the most likely outcomes of treatment (including the decision to observe rather than operate). Informed consent permeates most of the discussions physicians have with their patients, although the discussions may not be labeled as such. It applies to medication choices as much as to surgical decision making, although a separate consent form is generally not obtained each time a new medication is prescribed.

A patient is scheduled to undergo open abdominal aortic aneurysm repair. During preoperative testing, it is determined that his blood type is B negative. This means A. he has circulating antibodies to Rh antigens. B. he has circulating antibodies to A antigens. C. he has circulating antibodies to B antigens. D. he has no circulating antibodies to ABO antigens. E. his red blood cells have A antigens.

Answer: B Multiple blood cell antigens exist; however, the ABO and Rh antigens are most clinically relevant. A person with blood type B means his red cells have the B antigen. His plasma will have antibodies to the A antigen. In patients who are Rh negative, they will not have circulating antibodies to the Rh antigens unless they have been previously exposed (e.g., during pregnancy of an Rh-negative mother with an Rh-positive fetus). Hence, in this case, although he is Rh negative, he will not have circulating Rh antibodies.

A 48-year-old woman is in the hospital because of nausea, vomiting, and abdominal pain. She has a history of multiple abdominal surgeries for small bowel obstruction. On admission, she was quite thin with temporal and thenar muscle wasting. Her albumin level was 1.7 g/dL. A nasogastric tube was inserted and she has been receiving TPN for 2 days. You are now called by her nurse because, in addition to nausea and abdominal pain, she's begun to feel short of breath and have tingling in her fingers. She suddenly goes into cardiac arrest. Laboratory values now show potassium—2.4 mEq/L, magnesium—1.3 mEq/L, phosphorus—1 mg/dL, and glucose—350 mg/dL. What nutritional complication may have resulted in this patient's condition? A. Marasmus B. Refeeding syndrome C. Overfeeding D. Underfeeding E. Kwashiorkor

Answer: B Refeeding syndrome occurs when chronically starved patients lose the ability to tolerate acute changes in volume or caloric load. This results in a constellation of fluid, micronutrient, electrolyte, and vitamin imbalances within the first hours to days following nutrient infusion. These patients are typically hypokalemic, hypophosphatemic, hypomagnesemic, and hyperglycemic. This may result in symptoms, including hemolytic anemia, respiratory distress, paresthesias, tetany, and cardiac arrhythmias including sudden cardiac death. (Complications of Initiating Nutritional Therapy)

A 45-year-old man with a 25-year history of hepatitis C and cirrhosis is found to have a small hepatocellular carcinoma of the right lobe of the liver. In order to assess his risk for surgical therapy, an estimate of liver dysfunction given by the model for end stage liver disease (MELD) score is needed. Which one of the following laboratory studies is needed to calculate a MELD score for this patient? A. Alkaline phosphatase B. Serum creatinine C. Serum ammonia D. Serum albumin E. Serum gamma glutamyl transpeptidase (γ GT)

Answer: B The MELD score formula is (0.957 × ln(Serum Creatinine) + 0.378 × ln(Serum Bilirubin) + 1.120 × ln(INR) + 0.643 ) × 10 (if hemodialysis, value for creatinine is automatically set to 4). Albumin is a component of the Childs-Pugh classification, but not the MELD score. Alkaline phosphatase is useful in determining biliary tract obstruction. Gamma GT is very sensitive for hepatobiliary disease and is best used to determine if an isolated elevation of alkaline phosphatase is due to liver rather than bone disease.

A 46-year-old man is in the intensive care unit following surgery for multiple gunshot wounds to the chest and abdomen sustained 2 days ago. He has bilateral chest tubes inserted for hemopneumothoraces. Damage control surgery including packing his liver and performing an ileostomy was done at that time. His urine output has decreased to 90 mL over the past 4 hours. His temperature is 38°C, blood pressure (BP) 110/85 mm Hg, and pulse 100/minute. What is the most likely cause for the drop in urine output? A. Congestive heart failure B. Hypovolemia C. Acute renal failure D. Diabetes insipidus E. Sepsis

Answer: B The most common cause for a drop in urine output after surgery is hypovolemia. This can be caused by inadequate fl uid replacement to correct the sequestration of fl uid into the site(s) of injury, continuing blood loss, and stimulation of various endocrine responses including an increase in aldosterone, which results in renal sodium retention and an increase in antidiuretic hormone (ADH), which result in reduced free water clearance in the kidney. Atrial natriuretic factor may be inhibited due to the reduction in atrial volume and distention. The patient has a narrow pulse pressure and increased heart rate consistent with a low stroke volume and perhaps reduced cardiac output. The latter could be due to a combination of an absolute hypovolemia and/or a relative hypovolemia if he is developing an abdominal compartment syndrome, which could also contribute to decreasing urine output. The patient is relatively young to have congestive heart failure. Acute renal failure would be possible but is unusual only 2 days after surgery. Diabetes insipidus would result in increased urine output. Sepsis or an infl ammatory response syndrome would result in an increase in heart rate and a wider pulse pressure due to the vasodilation that occurs as a result of the release of various cytokines. In this patient, treatment would begin by performing a detailed physical exam followed by increased fl uid infusion.

A 27-year-old man is sprayed with concentrated sulfuric acid while working in an oil refi nery, sustaining burns to his face, hands, and forearms. He is brought immediately to the emergency room. On initial exam, he is awake and in pain. His clothes are soaked with acid. In addition to providing appropriate protection for all health care workers, the fi rst step in management should be to A. debride his burns and complete a Lund and Browder chart. B. immediately place the patient in a decontamination shower. C. perform a secondary survey. D. begin fluid resuscitation. E. contact the local burn center for referral.

Answer: B The patient illustrates the danger that health care workers face when dealing with hazardous material spills. Unwary physicians and nurses who attempt to help this man could suffer serious burns from the acid on his clothing, which is continuing to burn the patient as well. This chemical must be neutralized before a primary survey can be conducted safely. All of the other answers are appropriate steps in treatment but should not be performed until after the patient is decontaminated. Section: Special Problems in Burn Care. Subsection: Chemical and Electrical Burns.

A 6-year-old girl was burned in a house fi re and unable to escape. She was found unconscious by fi refi ghters, who intubated her at the scene. On arrival in the burn center, she is found to have carbonaceous sputum, elevated carboxyhemoglobin levels, and burns to 30% TBSA. You should inform her parents that inhalation injury signifi cantly increases the mortality rate of patients with major burns mostly due to A. increased metabolic rate and protein-calorie malnutrition. B. persistent pulmonary infection and eventual development of multiple organ failure. C. hypoxia. D. airway obstruction. E. increased fluid requirements for resuscitation.

Answer: B Though inhalation injury can produce immediate death from carbon monoxide poisoning and hypoxia, patients who survive the initial event should survive this problem. Similarly, airway obstruction is usually a treatable problem with limited time course. Pneumonia is the most worrisome complication of smoke inhalation, because it is often persistent/recurrent, and diffi cult to treat. Persistent infection—including pneumonia—often leads to development of the multiple organ failure syndrome, which is usually fatal. Section: Pathophysiology of Burn Injury. Subsection: Pathophysiology of Inhalation Injury.

A 32-year-old man is seen in the emergency department 45 minutes after a motor vehicle collision. His only injury is a long linear laceration beginning on the left temporal forehead at the hairline and extending posteriorly for 10 cm. The edges are still bleeding briskly and the EMTs described a large amount of blood at the scene. He did not lose consciousness. His last tetanus booster was 4 years ago. Which of the following is required for tetanus prophylaxis in this patient? A. Tetanus immune globulin only B. Nothing further at this time C. Tetanus toxoid only D. Tetanus immune globulin followed by a single tetanus toxoid booster E. Tetanus immune globulin followed by three tetanus boosters

Answer: B Wounds prone to the development of tetanus include those with extensive contamination with soil, deep puncture wounds from metal objects, exposure injury complicated with frostbite, and wounds >6 hours from time of injury (Table 8-8.). Linear lacerations in general are not prone to tetanus. The extent of blood loss does not affect the need for tetanus booster administration. The patient last received tetanus toxoid <5 years ago, so nothing further is required.

A 65-year-old woman with severe symptomatic anemia secondary to chronic renal disease is being transfused with packed red blood cells. A couple of minutes into the transfusion, she complains of back pain, chest pain, and shortness of breath. The most likely diagnosis is A. transfusion-related acute lung injury (TRALI). B. delayed hemolytic transfusion reaction. C. acute hemolytic transfusion reaction. D. transfusion-related volume overload. E. transfusion-related hyperkalemia.

Answer: C Acute hemolytic transfusion reactions are usually caused by clerical error resulting in the administration of ABO mismatched blood. Host antibodies bind to antigens in donor red blood cells resulting in hemolysis. This may result in renal failure and shock. Patients complain of shortness of breath, chest pain, and back pain. The most appropriate course of action is to stop the transfusion, provide supportive therapy, and have the blood rechecked. TRALI usually occurs after completion of transfusions. Volume overload and hyperkalemia are unlikely only minutes into a transfusion.

A 22-year-old man is transported emergently to the hospital after sustaining a stab wound to the left chest. On initial survey, his airway is patent and he is breathing spontaneously, but he appears to be in shock. Which of the following findings best supports your working diagnosis of pericardial tamponade? A. Central venous pressure of 8 mm Hg B. Crisp S1S2 on cardiac auscultation C. Paradoxical pulse of 18 mm Hg D. Left atrial distention E. Increased QRS voltage on ECG

Answer: C As the disease process progresses, pericardial tamponade results in decreased venous return, with resultant decreased stroke volume, hypoperfusion, and shock. Clinical evidence of tamponade includes an increased paradoxical pulse (>15 mm Hg; answer C). Other signs include elevated central venous pressure (rather than normal, answer A), muffl ed heart sounds (rather than crisp S1S2, answer B), left atrial collapse (rather than distension, answer D), and decreased QRS voltage on ECG (answer E).

A 42-year-old woman is seen in the infectious disease clinic because of a small laceration. She is a surgeon and was assisting a surgical resident with a colon resection when she was accidentally cut with a scalpel blade during the procedure. She has received all required immunizations. Antibodies against which virus could be measured in order to assess the effectiveness of the only vaccine to prevent infection potentially transmitted from the patient to the surgeon during the operative procedure? A. Human immunodeficiency virus B. Hepatitis C C. Hepatitis B D. Cytomegalovirus E. Tuberculosis

Answer: C HIV, hepatitis B, hepatitis C, and cytomegalovirus are transmitted by body fl uids and blood; therefore, they pose an occupational risk to the surgeon. There is currently a highly effective vaccine for the prevention of hepatitis B in the host. No such vaccine is available for the other viral infections. Tuberculosis is not a virus but also poses a risk to health care workers.

A 25-year-old woman is brought to the emergency department after involvement in a low-speed motor vehicle collision. She complains of feeling light-headed and states that she is 33 weeks pregnant. Vital signs are heart rate—90 beats/minute and BP—82/44 mm Hg. Abdominal examination reveals a gravid uterus but no tenderness. Chest x-ray is unremarkable, and FAST reveals no intraperitoneal fl uid. A viable intrauterine pregnancy is noted, and fetal heart tones are observed. The next step in management should be A. cesarean section. B. induction of labor with vaginal delivery. C. left lateral tilt positioning. D. diagnostic peritoneal lavage. E. MRI of the abdomen and pelvis.

Answer: C In the supine position, the gravid uterus compresses the inferior vena cava (IVC), resulting in decreased venous return to the heart and hypotension. Visibly pregnant trauma patients should be placed in the left lateral tilt position (while maintaining spinal precautions) to displace the gravid uterus from the IVC. Induction of labor and cesarean section would not be indicated in the absence of fetal distress. Diagnostic peritoneal lavage (DPL) is relatively contraindicated in pregnancy, as uterine or fetal injury may occur. MRI is not utilized in the acute evaluation of abdominal trauma.

A 25-year-old man is in the hospital recovering from open surgery for perforated appendicitis performed 5 days ago. Postoperatively his wound was left open with daily debridement and local dressing changes. Today, local anesthesia is applied and the wound is closed with a nylon suture at the bedside. This represents an example of A. primary closure. B. composite graft closure. C. delayed primary closure. D. healing by secondary intent. E. local flap closure.

Answer: C Surgical wounds can heal in several ways. An incised wound that is clean and suture closed is said to heal by primary intention. Primarily closed wounds are of a smaller volume in a clean surgical fi eld. Often, because of bacterial common contamination or tissue loss, a wound will be left open to heal by granulation tissue formation. This is healing by secondary intent, and the wound must synthesize granulation tissue, contract at the wound periphery, and eventually cover the surface area with epithelial cells. Delayed primary closure represents a combination of the fi rst two, consisting of the placement of sutures, allowing the wound to stay open for a few days, and then subsequent closure of the sutures. Delayed primary closure requires that the wound be free of excess bacteria. This is generally accomplished by good local wound care with irrigation and debridement if necessary during a postoperative interval. Wounds heal faster following delayed primary closure than by secondary intent.

A 52-year-old man is in the operating room undergoing an emergent laparotomy because of a perforated ulcer. There is free intraperitoneal perforation and approximately 2 L of murky green fl uid with obvious vegetable matter is suctioned from the peritoneal cavity. A Graham patch is performed to close the perforation. The abdomen is irrigated with normal saline and suctioned until all return is clear of green fl uid and vegetable matter. After closing the fascia the next most appropriate step would be A. interrupted skin closure. B. closure of skin with a skin closure polymer (i.e., Dermabond). C. wound left open and wound care until clean and granulating and then delayed closure. D. closure of skin with staples. E. subcuticular suture skin closure.

Answer: C This is a contaminated surgical fi eld. Wound infection in this setting can be as high as 15% of wounds, regardless of irrigating until clear. Allowing the wound to stay open with wound care until robust granulation is occurring and the wound bed is clean reduces this risk once the delayed closure is done. If the wound granulates but continues to have a high bacterial load, it can be allowed to heal by secondary intention.

A 63-year-old man with chronic obstructive pulmonary disease (COPD) caught his home on fi re while smoking in bed. He was trapped in the house for an unknown time period before fi refi ghters extricated him. He presents to the Emergency Center with severe facial blistering, singed nasal hairs, black intraoral mucosa, a swollen tongue, and carbonaceous sputum. His pulse oximetry reads 85% on room air, and he is obtunded. What is the next best step in management? A. Administer racemic epinephrine and steroids. B. Draw an arterial blood gas for carboxyhemoglobin levels. C. Secure his airway by endotracheal intubation. D. Place him on 10 L oxygen by humidifi ed facemask. E. Transfer him to the hyperbaric oxygen chamber.

Answer: C This man presents with every manifestation of inhalation injury, which is the most frequent cause of death in victims of structural fi res. Oxygen therapy is essential, but this man likely does not have an adequate airway. Securing his airway is the fi rst principle of treatment. Section: Initial Care of the Burn Patient. Subsection: Primary Survey

A 48-year-old man is being evaluated in the emergency department with fevers, chills, and abdominal pain for the past 24 hours. He has a history of hepatitis C infection following a blood transfusion 14 years ago for a large scalp laceration and orthopedic injuries sustained in a motor vehicle collision. He has not been to a physician for 5 years. He does not smoke or drink alcohol. He takes no medications. His temperature is 39°C and vital signs are: blood pressure (BP) 90/50 mm Hg, pulse 110/minute, and respirations 26/minute. A CT scan shows a single stone in the gallbladder that does not appear to be obstructing. The bile ducts are normal caliber and the gallbladder wall is not thickened. There is a moderate amount of fluid, mild small bowel distention, and stranding around the sigmoid colon as well as a small amount of free intraperitoneal gas around the liver. An aspirate of the peritoneal fluid shows leukocytes and mixed Gram positives and negatives on Gram stain. Laboratory values show a WBC of 19,000/mm3, total bilirubin 1.2 mg/dL, and alkaline phosphatase 40 U/L. In addition to fluid resuscitation and broad-spectrum antibiotics, what is the best step in management? A. Laparoscopic cholecystectomy B. Long-term antibiotics only C. Laparotomy D. Magnetic resonance cholangiopancreatography (MRCP) E. Endoscopic retrograde cholangiopancreatography (ERCP)

Answer: C This patient has secondary peritonitis. This usually involves perforation of a hollow viscus and thus involves contamination of the peritoneal cavity with multiple organisms. Gram stain and culture of the peritoneal fl uid usually shows a single organism in patients with primary peritonitis and this can be treated with antibiotics without surgical intervention. In this scenario, the CT scan shows stranding around the sigmoid and fl uid and evidence of free air suggestive of a diverticulitis with fecal peritonitis. Patients with underlying liver disease are prone to gallstones and are a common fi nding. There is no evidence of common bile duct obstruction that warrants further investigation since the alkaline phosphatase is normal.

A 19-year-old man is seen in the emergency department 20 minutes after a high-speed head-on collision with a tree, in which his car caught fi re. He was not wearing a seat belt and was ejected from the vehicle. In the emergency department, he is alert, but he does not remember what happened. He admits to drinking a few beers earlier. Blood pressure is 75/40 mm Hg and heart rate 140. His airway is patent. Breath sounds are equal bilaterally. Arterial blood gases reveal a PaO2 of 140, SaO2 of 98%, PaCO2 of 34, and pH of 7.33. He has burns to 15% TBSA, involving his anterior trunk and legs. His abdomen is covered with burns but appears distended; tenderness is hard to determine because of painful burn wounds. What is the most likely cause of his hypotension? A. Smoke inhalation injury B. Burn shock C. Intra-abdominal hemorrhage D. Ethanol intoxication E. Closed head injury

Answer: C This patient illustrates the importance of the secondary survey in victims of burn injury. This man's burns are too limited in extent to cause severe shock, especially so soon after injury. Smoke inhalation is doubtful, especially with good blood gases. There is no evidence for ethanol intoxication or closed head injury. Unless a second injury (i.e., abdominal trauma) is considered, it will not be diagnosed. Section: Initial Care of the Burn Patient. Subsection: Secondary Survey

A 55-year-old man is seen in clinic prior to undergoing elective repair of a large umbilical hernia. He is otherwise healthy and has had no previous surgery. He takes no medications. He does not smoke and does not drink alcohol. Except for a large reducible umbilical hernia, his physical exam is normal. Which micronutrient supplementation would NOT be beneficial to this patient to improve wound healing? A. Vitamin C B. Vitamin E C. Vitamin K D. Vitamin A E. Zinc

Answer: C Vitamins integral for wound healing are vitamin C and vitamin A. Vitamin C is required for the conversion of proline and lysine to hydroxyproline and hydroxylysine. Vitamin C defi ciency or scurvy leads primarily to the failure of collagen synthesis. Vitamin E is an antioxidant, aids in immune function and fi broblast stimulation, and inhibits prostaglandin synthesis. Selenium is important for lymphocyte function and protects membranes from free radical damage. Zinc is possibly the most essential element for wound healing. Zinc defi ciency leads to decreased fi broblast proliferation, decreased collagen synthesis, and likely decreased lymphocyte, cellular, and immunity. While vitamin A defi ciency impairs wound healing, supplemental vitamin A benefi ts wound healing. Vitamin A enhances immune function, macrophage proliferation, collagen synthesis, and epithelial integrity. Supplemental vitamin A therapy can improve wound healing in patients receiving corticosteroids, cancer patients, diabetics, and patients undergoing chemotherapy. Vitamin K is involved in coagulation factor formation.

A 46-year-old man with an enterocutaneous fistula has been maintained on TPN for several weeks. The fistula has healed and prior to removing the central line, the patient is given a unit of packed red blood cells through his central line for his chronic anemia. Two hours into his red cell infusion, a rapid response is called when the nurse discovers the patient comatose and hypotensive. What is the most likely cause of the patient's condition? A. Hypokalemia B. Transfusion reaction C. Hypoglycemia D. Air embolus E. Catheter-related sepsis

Answer: C When long-term infusion of highly concentrated glucose solutions is suddenly discontinued, the increased endogenous insulin levels precipitate hypoglycemia. A blood transfusion would be more likely to elevate rather than depress potassium levels. Transfusion reactions cause fever, back pain, hemolysis, and hypotension, but not coma. The air embolus could cause both shock and unconsciousness and is unlikely to be associated with a blood transfusion. Catheter-related sepsis could induce fever and hypotension, but not coma. (Transition from Parenteral to Enteral Nutrition)

A 68-year-old woman in the surgical intensive care unit is comatose 10 days after a motor vehicle crash during which she sustained a fractured right femur treated with an intramedullary rod within 24 hours of the injury. There were no other injuries noted on admission. She remains intubated due to hypoventilation. Vital signs are blood pressure (BP)—100/60 mm Hg and pulse—52 beats/minute. Her temperature is 35.4°C. Her chest is clear. There are no heart murmurs. Her abdomen is mildly distended but soft. There are no bowel sounds. The surgical site is healing well with no signs of infection. An electrocardiogram shows sinus rhythm with low-voltage QRS. Computed tomographic scan of her head is normal for her age. Laboratory studies show: Hemoglobin—8.2 g/dL Sodium—138 mEq/L Potassium—3.7 mEq/L Thyroid-stimulating hormone (TSH)—16.4 μU/mL (ref—0.5 to 5.0 μU/mL) T4—0.5 μg/dL (ref—5 to 12 μg/dL) What is the most likely diagnosis for her condition? A. Sick euthyroid syndrome B. Thyroid storm C. Myxedema coma D. Adrenal insuffi ciency of critical illness E. Graves' disease

Answer: C While rare, myxedema coma is the most severe form of hypothyroidism. Typical features of this condition include mental status changes ranging from lethargy to coma, hypothermia, sinus bradycardia, low-voltage QRS complex on electrocardiogram (ECG), hypoventilation, and ileus. An elevated TSH and severely depressed T4 levels confi rm the diagnosis. Sick euthyroid syndrome may be an adaptation to critical illness and is noteworthy for a depressed T3 level. Thyroid storm is severe hyperthyroidism and has features opposite of myxedema coma, including fever, high-output cardiac failure, and nearly nondetectable TSH with elevated T3 and T4 levels. The hallmark of adrenal insuffi ciency of critical illness is hypotension refractory to fl uids and vasoactive medications.

A 70-year-old woman is transferred from the surgery ward to the surgical intensive care unit because of hypotension 2 days after undergoing an open low anterior resection for a sigmoid cancer. The surgery went well with minimal blood loss. The tumor was found on routine colonoscopy, and she had no symptoms and was quite healthy and active prior to surgery. Her preoperative medications were multiple vitamins and calcium supplements. Since surgery she has been receiving maintenance intravenous fl uids and was stable until a few hours ago when she became hypotensive. Despite receiving boluses of normal saline and starting pressors (norepinephrine and vasopressin), she remains hypotensive. She is intubated because of lethargy and tachypnea. Her temperature is 37.4°C. Pupils are equal and reactive. Her chest is clear bilaterally. There are no heart murmurs. Her abdomen is soft and tender only near the lower midline incision. There are no localizing neurological findings. There is minimal urine output from a Foley catheter. Laboratory studies show: Hematocrit—33% (36% the day before) Sodium—129 mEq/L Potassium—5.1 mEq/L Glucose—108 mg/dL Arterial blood gases (ABGs) on 40% FiO2-pH—7.39 PCO2—38 mm Hg PO2—130 mm Hg U/A—no bacteria, negative leukocyte esterase What is the most likely diagnosis? A. Hemorrhage B. Anastomotic leak C. Pulmonary embolism D. Acute adrenal insufficiency E. Urosepsis

Answer: D Adrenal insuffi ciency of critical illness typically presents with hypotension refractory to fl uid resuscitation and vasoactive medications. Ventilator dependence, hyponatremia, hyperkalemia, and hypoglycemia can occur but are less commonly attributed to the adrenal dysfunction. While frequently seen with chronic adrenal insuffi ciency, hyperpigmentation, abdominal pain, nausea, weight loss, and fatigue are not typical symptoms in the critical care setting.

A 30-year-old man is in the intensive care unit where he is being treated for injuries sustained in a motor vehicle crash. He sustains multiple orthopedic injuries and a severe head injury. On hospital day 4, vital signs are BP—120/70 mm Hg, pulse—76/minute, and respiratory rate on a ventilator of 12/minute. His urine output is 20 mL/hour. Serum sodium is 120 mEq/L, BUN is 18 mg/dL, and creatinine is 1 mg/dL. What is the most likely diagnosis? A. Water intoxication due to inappropriate fluid infusion B. Central diabetes insipidus C. Lab error D. SIADH E. Increased aldosterone secretion due to hypovolemia

Answer: D Although water intoxication due to inappropriate fl uids is possible, in this patient it is unlikely since he has normal renal function as refl ected by his BUN and creatinine. If he were given inappropriate fl uids, he would diurese the extra fl uid. Central diabetes insipidus usually results in a marked increase in urine (free water) output and would result in an increase in sodium concentration. Laboratory error is always possible, and if there is any question of this possibility, the electrolytes should be rechecked prior to initiating therapy. Increased aldosterone secretion would result in sodium retention and therefore would maintain serum sodium concentration. The most likely scenario is an increase in ADH, in this case due to the increase in intracranial pressure due to the head injury. Since the patient has a wide pulse pressure and normal output, he is at least euvolemic. Therefore, an increase in ADH is "inappropriate" for the situation. If, however, the patient had signs of decreased vascular volume including a narrow pulse pressure and increased heart rate, then the increased ADH secretion would be "appropriate".

A 28-year-old ultimate fighter is seen in clinic 2 weeks after undergoing splenectomy for a ruptured spleen sustained during a prize fi ght. He is feeling well with minimal incisional pain. There is a midline laparotomy incision that appears to be healing well without evidence of infection or other problems. He wants to know when his incision will be healed enough for him to return to professional fi ghting. Regarding the tensile strength of his wound, A. it will increase steadily over the first 6 weeks and achieve maximal strength by 12 weeks. B. it will achieve maximal tensile strength at the point of maximal collagen deposition. C. it will take a full year for the wound to regain the same tensile strength as preoperatively. D. wound tensile strength reaches 90% at 26 weeks and this is its plateau. E. collagen deposition reaches a maximum level in the fi rst 6 weeks and is quickly degraded thereafter.

Answer: D Collagen secretion is initiated by fi broblasts in the fi rst 24 to 72 hours after injury. Peak collagen production begins by 1 week postinjury. By 3 weeks after injury, collagen synthesis and collagen deposition/degradation achieve a steady state. After 3 weeks, wound tensile strength remains <30%. As the maturation process takes place, tensile strength increases consistently until it plateaus approximately 6 months (26 weeks) after injury. This strength is generally around 90% of original tensile strength, and preinjury tensile strength will never be reached.

A 30-year-old man is brought to the emergency department after crashing his motorcycle at high speed into a concrete divider. He sustains severe trauma to the mid face and mandible and is lethargic upon arrival. He has copious amounts of bloody airway secretions and pulse oximetry reveals oxygen saturation levels of 82% to 85%. Two unsuccessful attempts have been made to place an orotracheal tube. The next step should be A. bag-valve mask ventilation. B. nasotracheal intubation. C. resuscitative thoracotomy. D. surgical cricothyroidotomy. E. bronchoscopy.

Answer: D In the primary survey, obtaining a patent airway is of paramount importance. The patient in this scenario has an unstable airway and poor systemic oxygenation, making the establishment of a defi nitive airway an urgent matter. Since orotracheal intubation attempts have failed, the next step is to perform a cricothyroidotomy. Bag-valve mask ventilation is unlikely to be successful in this circumstance and does not provide a defi nitive airway. Nasotracheal intubation is contraindicated in severe facial trauma as false passage into the cranium may occur. Resuscitative thoracotomy may restore circulation but does not provide an airway. Bronchoscopy may be utilized after establishment of an airway to clear blood or secretions. (Taken from Primary Survey: Airway).

A 66-year-old man is in the intensive care unit 10 days following colon resection for perforated diverticulitis. He has a history of chronic obstructive pulmonary disease (COPD) and is unable to wean from the ventilator. He has been maintained on total parenteral nutrition (TPN) and has started tube feeding. The most likely nutritional cause for failure to wean from the ventilator would be A. too much protein. B. refeeding syndrome. C. underfeeding. D. overfeeding. E. hyperphosphatemia.

Answer: D Patients with COPD have diffi culty weaning from the ventilator secondary to CO2 retention. Feeding with both TPN and enteral feeding is likely to provide glucose loads far in excess of 4 g/kg/day, resulting in lipogenesis. The respiratory quotient (RQ) for lipogenesis is 8.7, which signifi es a high CO2 production. This additional CO2 could make it very diffi cult for a COPD patient to wean from the ventilator. (Parenteral Nutrition Advantages and Disadvantages)

A 42-year-old woman is seen in clinic 2 weeks after undergoing left partial mastectomy and sentinel lymph node biopsy for stage 1 breast cancer. Whole breast radiation is recommended. She is concerned about the effects of radiation on her incision. Which of the following statements is least accurate regarding radiation effects and wound healing? A. Rapidly dividing cells are the least affected by radiation therapy. B. Radiation effects on fibroblasts should be negligible. C. Radiation causes increased amounts of collagen deposition. D. Long-term effects of radiation are often reversible after 24 months. E. Wound healing is impaired postradiation secondary to venous injury.

Answer: D The effects of external beam radiation often cause local tissue damage and impaired wound healing. Given the sensitivity of radiation to the various phases of the cell cycle, rapidly dividing cells are the most sensitive to radiation. Two major manifestations of impaired wound healing secondary to radiation are the result of direct injury to fi broblasts, leading to a lack of collagen, and endothelial cell injury resulting in ineffi cient wound healing. The effects of radiation are permanent and irreversible cell damage, as manifested by progressive fi brosis and obliterate endarteritis.

A 27-year-old man is in the intensive care unit 24 hours after an automobile collision. He has a left pneumothorax, multiple broken ribs, a ruptured spleen requiring splenectomy, a pelvic fracture, and bilateral femur fractures. He is intubated. He has received 6 units of PRBCs and is currently receiving IV fluids. Which one of the following best describes his metabolic response? A. Insulin is the major mediator of the stress response. B. Glycogen stores can be used for 7 days. C. Energy expenditure is decreased by 30%. D. Hepatic reprioritization of protein synthesis favors acute-phase proteins. E. Epinephrine and adrenocorticotropic hormone (ACTH) production are reduced.

Answer: D The injury stress response is mediated by the counter-regulatory hormones, including ACTH, epinephrine, glucagon, and cortisol, along with the proinfl ammatory cytokines such as interleukins 1 and 6. Insulin is diminished during this response. The stress response results in the marked increase of energy expenditure, which is proportional to the size of the stress. Glycogen stores are rapidly depleted within 12 to 24 hours. Protein synthesis in the liver is reprioritized to produce acute phase proteins.

A 34-year-old woman is thrown from a horse during a trail ride and brought to the emergency department 60 minutes after the accident. She is awake but appears to be mildly confused. She complains of left chest pain that is worsened with inspiration as well as generalized abdominal pain. On exam, her airway is patent and breathing unlabored. Her pulse is 110 beats/minute. Her blood pressure is 85/62. Her breath sounds are equal bilaterally. Her neck veins are fl at and her skin is cool. She is tender over her left lower ribs and left upper quadrant. You suspect that she has sustained an injury to her spleen with resultant hemorrhage. Approximately what percentage of intravascular volume loss has she experienced? A. 0% B. 10% C. 20% D. 30% E. 50%

Answer: D The patient described in the scenario has suffered a splenic injury and progressive hemorrhage over the course of the hour leading up to presentation. She is demonstrating progressive hemodynamic effects from volume loss as described in Table 5-12, including mild tachycardia and hypotension, altered mental status, and decreased skin perfusion. Blood volume loss of 0% to 10% produces little change in hemodynamics or physical exam (answers A and B). Blood loss of 20% over 1 hour results in increased pulse, but normal blood pressure, mentation, and skin palpation (answer C). Blood loss of 30% is associated with mild hypotension, tachycardia, altered mental status, skin vasoconstriction, and decreased urine output (answer D; correct answer). Loss of 50% of blood volume is associated with severe physiological derangements, including profound hypotension, severe tachycardia, obtunded mental status, and anuria (answer E).

A 71-year-old man is admitted to the intensive care unit in septic shock secondary to pneumonia. His BP is 85/40 mm Hg and heart rate 95 beats/minute. Which of the following medications would be the most appropriate to use to treat his hypotension? A. Epinephrine B. Dobutamine C. Milrinone D. Dopamine E. Norepinephrine

Answer: E Dobutamine is a beta-agonist. Milrinone is a phosphodiesterase inhibitor. Both are commonly used for the management of cardiogenic shock. Epinephrine and dopamine have mixed alpha- and beta-receptor activity. Dopamine also stimulates dopaminergic receptors. Tachycardia is a frequent side effect. Norepinephrine stimulates mainly alpha receptors, with some beta-receptor activity. Thus, it is the drug of choice for patients with distributive shock, for example, sepsis.

A 26-year-old man is brought to the emergency department (ED) after being stabbed in the left arm in a fight. Brisk bleeding from the wound was controlled by the EMTs with a pressure bandage. Fifteen minutes later in the emergency department, the bandage is removed and only slight oozing is noted.The most likely mechanism for decreased bleeding at this time is A. platelet activation and aggregation. B. activation of the extrinsic coagulation cascade pathway. C. activation of prothrombin to thrombin. D. activation of the intrinsic coagulation cascade pathway. E. local peripheral vascular vasoconstriction.

Answer: E Hemostasis involves the blood vessel wall, platelets, and the coagulation cascade leading to fi brin deposition. After injury, local vasoconstriction is the fi rst hemostatic process to occur. This is followed by platelet adherence, activation, and aggregation. Finally, the coagulation cascade leads to the deposition of fi brin.

A 22-year-old man is brought to the emergency department after falling from a 10-foot ladder, landing on his left side. He has multiple left-sided rib fractures and a pneumothorax requiring a chest tube. Physical examination of the abdomen is unremarkable. He remains hemodynamically stable throughout the primary and secondary surveys and undergoes contrast-enhanced CT scanning of the abdomen and pelvis. CT scan reveals a grade II laceration of the spleen, with no evidence of active contrast extravasation. The next appropriate step in management is A. exploratory laparotomy with splenectomy. B. exploratory laparotomy with splenorrhaphy. C. splenic angioembolization. D. video-assisted thoracoscopy with evacuation of hemothorax. E. observation with serial abdominal examinations.

Answer: E Most low-grade splenic injuries can be managed nonoperatively. The key factor is hemodynamic stability of the patient. In this patient, splenectomy and splenorrhaphy would represent unnecessary surgical options, and interventional techniques such as angioembolization should be reserved for cases of high-grade splenic injury with active extravasation of intravenous contrast. Thoracoscopy is indicated for evacuation of residual hemothorax or diagnosis of penetrating diaphragmatic injury. (Taken from Abdominal Injury: Injury to Specifi c Organs: Spleen).

Which of the following patients is at the lowest risk for postoperative deep vein thrombosis? A. An 18-year-old male with femur and lumbar fractures B. A 55-year-old morbidly obese female undergoing total knee replacement C. A 62-year-old man undergoing prostatectomy for cancer D. A 45-year-old woman undergoing hysterectomy and bilateralsalpingo-oophorectomy and debulking for ovarian carcinoma E. A 38-year-old woman undergoing carpal tunnel release

Answer: E Patients who are immobile, who have congestive heart failure or malignancy, who undergo pelvic or joint replacement operations, or who have vertebral, pelvic, or long bone fractures are at highest risk. Carpal tunnel release does not confer increased risk of deep vein thrombosis.

A 45-year-old man was admitted to the hospital 3 days ago with nausea and vomiting due to a gastric outlet obstruction. Further studies have confirmed a gastric cancer involving the antrum of the stomach. He has a history of alcohol abuse and being homeless. The patient is thin and has temporal wasting and exposed ribs. He has an albumin of 1.9 g/dL. A nasogastric tube was placed on admission, and he was started on TPN. What is his surgical risk for perioperative complications? A. Moderate risk for developing surgical complications B. Moderate risk for developing wound complications only C. Low risk for developing surgical complications D. Cannot assess risk for surgical complications E. High risk for developing surgical complications

Answer: E Patients with a poor baseline nutritional status undergoing surgery are more likely to have increased morbidity and mortality. There is a linear increase in complications in patients undergoing elective gastrointestinal surgery as preoperative albumin decreases from normal to levels below 2 g%. Criteria to consider when screening surgical patients for nutritional risk include magnitude of the procedure, medications, recent weight changes, cachexia, changes in diet or appetite, and serum albumin. (Assessment of Nutritional Status)

A 75-year-old woman with a history of congestive heart failure underwent elective sigmoid resection for severe recurrent diverticulitis. Postoperatively, she experiences shortness of breath. Physical exam and chest radiography suggest the presence of pulmonary edema. Which of the following parameters is the most accurate determinant of her left ventricular preload? A. Central venous pressure B. Pulmonary artery occlusive pressure C. Systemic vascular resistance D. Pulmonary venous pressure E. Left ventricular end-diastolic volume

Answer: E Preload is defi ned as the amount of myocardial stretch prior to myocardial contraction. Increased stretch leading to increased myocardial contraction is described by the Frank-Starling mechanism. Preload is most closely related to end-diastolic volume (answer E). Several other factors, including central venous pressure, pulmonary artery occlusive pressure, and pulmonary venous pressure, may also be used to estimate preload, but they are not as accurate as left ventricular end-diastolic volume for this purpose (answers A, B, and D). Systemic vascular resistance (C) is not mathematically related to preload.

A 35-year-old man is admitted for a sigmoid colectomy due to repeated episodes of acute diverticulitis. He weighs 140 kg, but his ideal body weight is 80 kg. Which of the following body compositions should be used as a basis for calculating basic maintenance fluids for this patient? Total Body Water (L) Intracellular Water (L) Extracellular Water (L) Blood Volume (L) A. 84 55 28 9.8 B. 70 55 15 8.4 C. 56 35 21 8.4 D. 54 32 22 5.4 E. 60 40 20 7.5

Answver: D The composition of the body varies with lean body mass (muscle) and the fat content. If one assumes that "ideal body weight" is related to the theoretical "young healthy male" discussed in most textbooks where total body water is 60% of weight and intracellular volume is 60% of total body water, then for 80 kg, the patient would have 48 L of total body water, 32 L of intracellular water, and 16 L of extracellular water. Since fat is only about 10% water, the extra 60 kg of fat only adds 6 L of water. Therefore in this patient, total body water would only be 54 L. Intracellular water changes little and therefore the ICF would be about 32 L and the ECF about 22 L. Vascular volume for the 80-kg weight would only be a little more than 6% of weight (6.3 ± 0.4%) or about 5 L. The additional 6 L of fat would add little to the blood volume so 5.4 L total blood volume would be a close approximation. The clinical signifi cance of these "estimations" relates to numerous clinical scenarios. For example, if one estimates that there is a serum sodium defi cit of 10 mEq/L in this patient but assumes total body water is 60% of total weight, the patient would get 10 × 84 L of total body water or 840 mEq of sodium instead of 10 × 54 L of total body water or 540 mEq of sodium. The extra and unnecessary 300 mEq of sodium is equivalent to 2 L of normal saline. If one calculates total body water requirements for daily maintenance using the standard "70-kg male" as a reference, then the 140-kg male would receive 35 mL/kg (Table 2-2) or about 4.9 L of fl uid. However, using "ideal body weight" for the calculation and adding only about 10% for the increased fat content, the total fl uid would instead be about 3 L. If the extra 1.9 L is given over 3 or 4 days and if the kidneys do not excrete this fl uid due to numerous conditions such as syndrome of inappropriate antidiuretic hormone (SIADH), the patient in 3 days is up almost 6 L that may not be visible in this obese patient. This increased total body water could result in a host of effects including peripheral edema, pleural effusions, and cardiac and pulmonary dysfunction; lead to subtherapeutic drug levels (since many drugs such as antibiotics have volumes of distributions equivalent to extracellular or total body water); cause secondary complications from each of these effects and overall delay in discharge from hospital; and increase costs. In other words, a more accurate "guesstimate" using a similar thought process for patients decreases complications, reduces hospital stay, and reduces costs.