Exam 3

Identify the following ABG: pH is 7.44 PaCO2 is 41 HCO3 is 39 A. Fully compensated Respiratory Acidosis B. Partially compensated Metabolic Acidosis C. Uncompensated Respiratory Alkalosis D. Fully compensated Metabolic Alkalosis

D

Identify the following ABG: pH is 7.51 PaCO2 is 38 HCO3 is 34 A. Respiratory Acidosis B. Metabolic Acidosis C. Respiratory Alkalosis D. Metabolic Alkalosis

D

A patient who was involved in a motor vehicle crash has had a tracheostomy placed to allow for continued mechanical ventilation. How should the nurse interpret the following arterial blood gas results: pH 7.48, PaO2 85 mm Hg, PaCO2 32 mm Hg, and HCO3 25 mEq/L? A. Respiratory Alkalosis B. Metabolic Alkalosis C. Respiratory Acidosis D. Metabolic Acidosis

A

A critical care nurse who is new to the unit asks the clinical nurse specialist about the difference between noninvasive ventilation and oxygen delivery. Which statement would the clinical nurse specialist include about noninvasive ventilation in the response? A. It delivers higher pressures during inspiration. B. It ensures oxygen delivery when the client is unable to do so on his own. C. It provides extra oxygen delivery during acute episodes. D. It maintains respiratory function.

A Noninvasive ventilation (NIV) appears similar to the methods of oxygen delivery discussed previously, but it is, in fact, not the same. NIV provides a greater pressure on the inspiratory phase than on expiration, unloading the work of the respiratory muscles and providing complete respiratory support. Some clients will receive O2 therapy as a preventive measure. Supplemental oxygen will assist some clients with extra oxygen delivery during acute episodes, such as in cases of myocardial infarction (MI). For the more critically ill, it will serve as an intervention to ensure oxygen delivery when they are unable to maintain their own ventilatory or respiratory function.

A nurse is preparing to measure a client's pulmonary artery wedge pressure. When obtaining this measurement, the nurse understands that this reading reflects which information? A. pressure in the left ventricle at end of diastole B. average pressure in the pulmonary artery throughout the cardiac cycle C. pressure in the pulmonary artery during systole D. pressure at the level of the right atrium

A Pulmonary artery wedge pressure is an indirect measurement of the pressure in the left ventricle at the end of diastole. Mean pulmonary artery pressure is the average pressure in the pulmonary artery throughout the cardiac cycle. Pulmonary artery systolic pressure is the pressure in the pulmonary artery during systole. Right atrial pressure is the pressure at the level of the right atrium.

A critical care nurse providing care to a client with a cardiac condition is determining the client's cardiac output. Which component would the nurse use to determine this measurement? Select all that apply. A. stroke volume B. heart rate C. pulmonary vascular resistance D. mean arterial pressure E. cardiac index

A,B Cardiac output is determined by multiplying the client's stroke volume by heart rate. Cardiac index, pulmonary vascular resistance, and mean arterial pressure are not used to determine cardiac output.

A nurse is providing care to a client in the critical care unit who is experiencing altered mental status. The nurse uses the mnemonic AEIOUTIPS to address the possible causes. When applying the T portion of the mnemonic, which cause would the nurse identify as a possibility? Select all that apply. A. trauma B. temperature C. thyroid dysfunction D. transient ischemic attack E. tachypnea

A,B When applying the T portion of the mnemonic, the nurse would identify trauma and temperature as possible causes of altered mental status. Thyroid dysfunction, TIA or tachypnea are not part of the mnemonic.

A client in the critical care unit has undergone insertion of a pulmonary artery catheter. When providing care for this client, the nurse would be alert for signs and symptoms of which complication? Select all that apply. A. pneumothorax B. dysrhythmia C. pulmonary artery rupture D. increased preload E. increased afterload

A,B,C Complications such as pneumothorax, cardiac dysrhythmias, and pulmonary artery rupture are possible with insertion of a pulmonary artery catheter. Increased preload occurs with increased fluid volume and vasoconstriction; increased afterload occurs with hypovolemia and vasoconstriction.

A client has a pulmonary artery catheter in place. When evaluating the client's mean arterial pressure, which value would the nurse report to the health care provider immediately? A. 55 mm Hg B. 70 mm Hg C. 85 mm Hg D. 100 mm Hg

A. Normal MAP readings range from 70 to 105 mm Hg. Therefore a reading of 55 mm Hg should be reported to the health care provider immediately.

A nurse is providing care to a client receiving mechanical ventilation when the high pressure alarm sounds on the ventilator. The nurse troubleshoots the problem. Which assessment would the nurse identify as a possible cause for the alarm? Select all that apply A. client biting the endotracheal tube B. kinked tubing C. client experiencing bronchospasm D. airway displacement E. tubing disconnection

A,B,C A high-pressure alarm usually indicates resistance to or obstruction of airflow from biting on the ETT, a kink in the tubing, or something as severe as bronchospasm or pneumothorax. Pressure alarms on the ventilator may indicate a dangerous situation. Low-pressure alarms may indicate disconnection from the machine or displacement of the airway.

A critical care nurse is reviewing a journal article about respiratory failure. The nurse demonstrates understanding of the information by identifying which condition as a cause of hypoxemic respiratory failure? Select all that apply, A. anemia B. acute respiratory distress syndrome C. hemorrhage D. airway obstruction E. spinal cord injury

A,B,C Rationale: Causes of hypoxemic respiratory failure (too little oxygen reaches the tissues) include anemia, hemorrhage, intracardiac shunts, and acute respiratory distress syndrome (ARDS). Airway obstruction and spinal cord injury are causes of ventilatory respiratory failure in which too little oxygen is exchanged for carbon dioxide.

A patient who is being treated for pneumonia starts complaining of sudden shortness of breath. An arterial blood gas (ABG) is drawn. The ABG has the following values: pH 7.21, PaCO 2 64 mm Hg, HCO 3 = 24 mm Hg. What does the ABG reflect? A. Respiratory acidosis B. Metabolic alkalosis C. Respiratory alkalosis D. Metabolic acidosis

A.

The nurse is caring for a patient in the ICU whose condition is deteriorating. The nurse receives orders to initiate an infusion of dopamine. What would be the priority assessment and interventions specific to the administration of vasoactive medications? A. Frequent monitoring of vital signs, monitoring the central line site, and providing accurate drug titration B. Reviewing medications, performing a focused cardiovascular assessment, and providing patient education C. Reviewing the laboratory findings, monitoring urine output, and assessing for peripheral edema D. Routine monitoring of vital signs, monitoring the peripheral IV site, and providing early discharge instructions

A.

A client is receiving norepinephrine (Levophed) for shock. What assessment finding best indicates a therapeutic effect from this drug? A. Alert and oriented, answering questions B. Client denial of chest pain or chest pressure C. IV site without redness or swelling D. Urine output of 30 mL/hr for 2 hours

A. Normal cognitive function is a good indicator that the client is receiving the benefits of norepinephrine. The brain is very sensitive to changes in oxygenation and perfusion. Norepinephrine can cause chest pain as an adverse reaction, so the absence of chest pain does not indicate therapeutic effect. The IV site is normal. The urine output is normal, but only minimally so.

A critical care nurse is providing care to a client who requires a pacemaker. The client has electrodes placed on the front and side of the chest. The nurse identifies this as which type of pacemaker? A. external pacemaker B. transvenous C. epicardial D. transthoracic

A. External pacemakers involve placement of electrodes on the front and side or back of the chest to deliver repeated shocks. Transvenous pacemakers involve placement of a wire into the right ventricle via a central IV catheter. Epicardial pacemaker involves surgical placement of wires into the epicardium to prevent and treat postsurgical conduction defects. Transthoracic cardiac pacemakers involve introduction of a wire into the right ventricle, which is attached to a generator.

You are the nurse caring for a 77-year-old male patient who has been involved in a motor vehicle accident. You and your colleague note that the patient's labs indicate minimally elevated serum creatinine levels, which your colleague dismisses. What can this increase in creatinine indicate in older adults? A. Substantially reduced renal function B. End-stage Renal Disease C. Decreased cardiac output D. Alterations in ratio of body fluids to muscle mass

A. Normal physiologic changes of aging, including reduced cardiac, renal, and respiratory function, and reserve and alterations in the ratio of body fluids to muscle mass, may alter the responses of elderly people to fluid and electrolyte changes and acid-base disturbances. Renal function declines with age, as do muscle mass and daily exogenous creatinine production. Therefore, high-normal and minimally elevated serum creatinine values may indicate substantially reduced renal function in older adults. ESRD is likely to cause a more significant increase in serum creatinine.

A nurse providing care to a client in the critical care unit implements interventions to reduce the client's pain. The nurse implements these measures based on the understanding that they will help to achieve which result? A. lessen the body's stress response B. increase catabolism C. increase cardiac workload D. reduce the immune response

A. Rationale: It is well known that pain elicits a stress response, leading to a catabolic state with increased cardiac workload and an impaired immune response. Care must be taken to ensure that all ICU patients are assessed for any pain, whether or not they are able to communicate their pain level.

A critical care nurse providing care to a client receiving mechanical ventilation identifies that the client is at risk for gastrointestinal bleeding. Which agent would the nurse anticipate administering if prescribed? A. pantoprazole B. sucralfate C. aluminum hydroxide D. heparin

A. Rationale: The incidence of GI bleeding has decreased over the last few decades and is largely due to standard administration of proton pump inhibitors (PPIs, such as pantoprazole) or H2-histamine antagonists (such as ranitidine). Sucralfate, aluminum hydroxide, and heparin would not be used.

A patient is brought to the ED by two police officers. The patient was found unconscious on the sidewalk, with his face and hands covered in blood. At present, the patient is verbally abusive and is fighting the staff in the ED, but appears medically stable. The decision is made to place the patient in restraints. What action should the nurse perform when the patient is restrained? A. Frequently assess the patient's skin integrity. B. Inform the patient that he is likely to be charged with assault. C. Avoid interacting with the patient until the restraints are removed. D. Take the opportunity to perform a full physical assessment.

A. It is important to assess skin integrity when physical restraints are used. Criminal charges are not the responsibility of the nurse and the nurse should still interact with the patient. A full physical assessment, however, would likely be delayed until the patient is not combative.

A client is admitted to the critical care unit with hypertensive crisis and is prescribed vasoactive medication. Which medication would the nurse anticipate administering? A. nitroprusside sodium B. dobutamine C. dopamine D. vasopressin

A. Nitroprusside sodium decreases blood pressure and is used to treat hypertensive crisis. Dopamine, dobutamine, and vasopressin increase blood pressure and would not be used.

A patient who has been in the intensive care unit for 4 days has disturbed sensory perception from sleep deprivation. Which action should the nurse include in the plan of care? A. Administer prescribed sedatives or opioids at bedtime to promote sleep B. Cluster nursing activities so that the patient has uninterrupted rest periods C. Silence the alarms on the cardiac monitors to allow 30- to 40-minute naps D. Eliminate assessments between 2200 and 0600 to allow uninterrupted sleep

B

A patient with a longstanding diagnosis of generalized anxiety disorder presents to the emergency room. The triage nurse notes upon assessment that the patient is hyperventilating. The triage nurse is aware that hyperventilation is the most common cause of which acid-base imbalance? A. Respiratory acidosis B. Respiratory alkalosis C. Increased PaCO 2 D. CNS disturbances

B

A student is caring for a client who suffered massive blood loss after trauma. How does the student correlate the blood loss with the client's mean arterial pressure (MAP)? A. It causes vasoconstriction and increased MAP. B. Lower blood volume lowers MAP. C. There is no direct correlation to MAP. D. It raises cardiac output and MAP.

B

The nurse is caring for an elderly man who was admitted for dyspnea, fever, and a productive cough. Assessment reveals wheezes and crackles. He is tachycardic with a bounding pulse. Results of his ABG' s are: pH 7.2, PCO2 66 mmHg, PO2 71 mmHg, HCO3 27 mmol/L. How would the nurse interpret these results? A. Respiratory Alkalosis Uncompensated B. Respiratory Acidosis Partially Compensated C. Respiratory Acidosis Uncompensated D. Respiratory Acidosis Fully Compensated

B

A nurse is caring for a patient with ARDS who is being treated with mechanical ventilation and high levels of positive end-expiratory pressure (PEEP). Which assessment finding by the nurse indicates that the PEEP may need to be reduced? A. The patient's PaO2 is 50 mm Hg and the SaO2 is 88%. B. The patient has subcutaneous emphysema on the upper thorax C. The patient has bronchial breath sounds in both the lung fields. D. The patient has a first-degree atrioventricular heart block with a rate of 58 beats/min.

B The subcutaneous emphysema indicates barotrauma caused by positive pressure ventilation and PEEP. Bradycardia, hypoxemia, and bronchial breath sounds are all concerns and will need to be addressed, but they are not specific indications that PEEP should be reduced.

After surgery for an abdominal aortic aneurysm, a patient's central venous pressure (CVP) monitor indicates low pressures. Which action should the nurse take? A. Administer IV diuretic medications B. Increase the IV fluid infusion per protocol. C. Increase the infusion rate of IV vasodilators. D. Elevate the head of the patient's bed to 45 degrees.

B low CVP indicates hypovolemia and a need for an increase in the infusion rate. Diuretic administration will contribute to hypovolemia and elevation of the head or increasing vasodilators may decrease cerebral perfusion.

WHich action provides the most accurate way to verify the correct placement of an oral endotracheal tube (ET) after insertion? A. obtain a portable chest x-ray B. use an end-tidal CO2 monitor. C. auscultate for bilateral breath sounds D. observe for symmetrical chest movement

B.

A client in the critical care unit is being prepared for insertion of an intra-aortic balloon pump. When teaching the client about the device, which information would the nurse most likely include? A. "The device will be inserted through an artery in your neck." B. "The device will decrease the work your heart needs to do to pump." C. "The device will work whenever your heart beat gets irregular." D. "The balloon inflates when your heart contracts."

B. A balloon in placed in the descending aorta via a femoral artery. The balloon can be alternately inflated and deflated. It is programmed to inflate during diastole, which pushes blood back toward the cardiac muscle itself, as well as toward the brain. It deflates just before the ejection phase of systole and acts as a vacuum that pulls blood into the aorta with less effort from the left ventricle. An IABP essentially decreases the workload of the heart, allowing the heart muscle to rest and recover while improving organ perfusion. The machine itself can be programmed to assist with every heartbeat or every second, third, or fourth alternate beat, depending upon client requirements.

The nurse is caring for a patient in the ICU. The patients BP is 82/53, heart rate 123, and central venous pressure is 1 mm Hg. Which would be the most appropriate order for the nurse to administer? A. Levophed B. 2 L Normal Saline bolus C. Dopamine D. Epinephrine

B. CVP of less than 2 indicates dehydration. Vassopressors need volume to be effective

A medical nurse educator is reviewing a patient's recent episode of metabolic acidosis with members of the nursing staff. What should the educator describe about the role of the kidneys in metabolic acidosis? A. The kidneys retain hydrogen ions and excrete bicarbonate ions to help restore balance. B. The kidneys excrete hydrogen ions and conserve bicarbonate ions to help restore balance. C. The kidneys react rapidly to compensate for imbalances in the body. D. The kidneys regulate the bicarbonate level in the intracellular fluid.

B. The kidneys regulate the bicarbonate level in the ECF; they can regenerate bicarbonate ions as well as reabsorb them from the renal tubular cells. In respiratory acidosis and most cases of metabolic acidosis, the kidneys excrete hydrogen ions and conserve bicarbonate ions to help restore balance. In respiratory and metabolic alkalosis, the kidneys retain hydrogen ions and excrete bicarbonate ions to help restore balance. The kidneys obviously cannot compensate for the metabolic acidosis created by renal failure. Renal compensation for imbalances is relatively slow (a matter of hours or days).

A patient is admitted to the ED with an apparent overdose of IV heroin. After stabilizing the patient's cardiopulmonary status, the nurse should prepare to perform what intervention? A. Administer a bolus of lactated Ringer's. B. Administer naloxone hydrochloride (Narcan). C. Insert an indwelling urinary catheter. D. Perform a focused neurologic assessment.

B. Rationale: Narcan is an opioid antagonist that is administered for the treatment of narcotic overdoses. There is no definitive need for a urinary catheter or for a bolus of lactated Ringer's. The patient's basic neurologic status should be ascertained during the rapid assessment, but a detailed examination would be take precedence over administration of an antidote.

A client in the critical care unit has developed class IV heart failure and is not considered a candidate for transplantation. Based on the nurse's knowledge of treatment, the nurse would anticipate which intervention? A. intra-aortic balloon pump B. ventricular assist device C. pacemaker D. vasoactive medication

B. Rationale: VADs are reserved for clients who cannot be weaned from maximum volume/inotropic support or the IABP, are awaiting cardiac transplantation, or have class IV heart failure but are not candidates for transplantation. Vasoactive medications, pacemaker, and intra-aortic balloon pump would be used prior to deciding to use a VAD.

The nurse is caring for a patient admitted with renal failure and metabolic acidosis. Which clinical manifestation would indicate to the nurse that planned interventions to relieve the metabolic acidosis have been effective? A. Tachypnea B. Palpitation C. Increased depth tendon reflexes D. Decreased depth of respirations

D

A nurse is using the Richmond Agitation-Sedation Scale to assess a client's anxiety level. The nurse notes that the client is drowsy and is able to maintain eye contact to the nurse's voice for about 15 to 20 seconds. The nurse would document which score for the client? A. +1 B. 0 C. -1 D. -2

C

The nurse in the medical ICU is caring for a patient who is in respiratory acidosis due to inadequate ventilation. What diagnosis could the patient have that could cause inadequate ventilation? A. Endocarditis B. Multiple myeloma C. Guillain-Barré syndrome D. Overdose of amphetamines

C

The nurse notes that a patient's endotracheal tube (ET), which was at the 22-cm mark, is now at the 25-cm mark, and the patient is anxious and restless. Which action should the nurse take next? A. Check the O2 saturation. B. Offer reassurance to the patient. C. Listen to the patient's breath sounds D. Notify the patient's health care provider.

C

You are caring for a 65-year-old male patient admitted to your medical unit 72 hours ago with pyloric stenosis. A nasogastric tube placed upon admission has been on low intermittent suction ever since. Upon review of the morning's blood work, you notice that the patient's potassium is below reference range. You should recognize that the patient may be at risk for what imbalance? A. Hypercalcemia B. Metabolic acidosis C. Metabolic alkalosis D. Respiratory acidosis

C

he nurse is reviewing the latest arterial blood gas results for a patient with metabolic alkalosis. Which result indicates that the metabolic acidosis is compensated? A. PO2 104 mmHg B. HCO3 8 mEq/L C. PCO2 48 mmHg D. PCO2 18 mmHg

C

When caring for a patient with pulmonary hypertension, which parameter will the nurse use to directly evaluate the effectiveness of the treatment? A. Central venous pressure (CVP B. Systemic vascular resistance (SVR) C. Pulmonary vascular resistance (PVR) D. Pulmonary artery wedge pressure (PAWP)

C PVR is a major contributor to pulmonary hypertension, and a decrease would indicate that pulmonary hypertension was improving. The other parameters may also be monitored but do not directly assess for pulmonary hypertension.

Dopamine has been prescribed for a patient who was admitted with dehydration and hypotension. Which patient data indicate that the nurse should consult with the health care provider before starting the Dopamine? A. The patient is receiving low dose Epinephrine B. The patient's central venous pressure is 5 mm Hg. C. The patient is in sinus tachycardia at 120 beats/min D. The patient has had no urine output since being admitted.

C.

The nurse is preparing to insert a peripheral IV catheter into a patient who will require fluids and IV antibiotics. How should the nurse always start the process of insertion? A. Leave one hand ungloved to assess the site. B. Cleanse the skin with normal saline. C. Ask the patient about allergies to latex or iodine. D. Remove excessive hair from the selected site.

C.

Which statement by the nurse when explaining the purpose of positive end-expiratory pressure (PEEP) to the patient's caregiver is accurate? A. "PEEP will push more air into the lungs during inhalation." B. "PEEP will prevent lung damage while the patient is on the ventilator." C. "PEEP prevents the lung air sacs from collapsing during exhalation." D. "PEEP allows the breathing machine to deliver 100% O2 to the lungs."

C. By preventing alveolar collapse during expiration, PEEP improves gas exchange and oxygenation. PEEP will not prevent lung damage (e.g., fibrotic changes that occur with ARDS), push more air into the lungs, or change the fraction of inspired oxygen (FIO2) delivered to the patient.

One day after a patient is admitted to the medical unit, you note that the patient is oliguric. You notify the acute-care nurse practitioner who orders a fluid challenge of 500 mL of normal saline solution over 15 minutes. This intervention will achieve which of the following? A. Help distinguish hyponatremia from hypernatremia B. Help evaluate pituitary gland function C. Help distinguish reduced renal blood flow from decreased renal function D. Help provide an effective treatment for hypertension-induced oliguria

C. If a patient is not excreting enough urine, the health care provider needs to determine whether the depressed renal function is the result of reduced renal blood flow, which is a fluid volume deficit (FVD or prerenal azotemia), or acute tubular necrosis that results in necrosis or cellular death from prolonged FVD. A typical example of a fluid challenge involves administering 500 mL of normal saline solution over 15 minutes. The response by a patient with FVD but with normal renal function is increased urine output and an increase in blood pressure. Laboratory examinations are needed to distinguish hyponatremia from hypernatremia. A fluid challenge is not used to evaluate pituitary gland function. A fluid challenge may provide information regarding hypertension-induced oliguria, but it is not an effective treatment.

A client in shock has been started on dopamine. What assessment finding requires the nurse to communicate with the provider immediately? A. Blood pressure of 98/68 mm Hg B. Pedal pulses 1+/4+ bilaterally C. Report of chest heaviness D. Urine output of 32 mL/hr

C. Chest heaviness or pain indicates myocardial ischemia, a possible adverse effect of dopamine. While taking dopamine, the oxygen requirements of the heart are increased due to increased myocardial workload, and may cause ischemia. Without knowing the client’s previous blood pressure or pedal pulses, there is not enough information to determine if these are an improvement or not. A urine output of 32 mL/hr is acceptable

ou are caring for a patient with a secondary diagnosis of Metabolic Alkalosis, which compensatory mechanism would the nurse expect to find on assessment? A. Tachycardia B. Kussmaul respirations C. Tachypnea D. Shallow respirations

D

BONUS: Diagnostic testing has been ordered to differentiate between normal anion gap acidosis and high anion gap acidosis in an acutely ill patient. What health problem typically precedes normal anion gap acidosis? A. Metastases B. Excessive potassium intake C. Water intoxication D. Excessive administration of chloride

D.

The patient who has had diarrhea for the last 3 days has blood gases of pH of 7.1, HCO3- of 20 mEq/L, and PCO2 of 36 mm Hg. These laboratory values are consistent with which acid-base imbalance? A. Respiratory alkalosis B. Respiratory acidosis C. Metabolic alkalosis D. Metabolic acidosis

D.

You are an emergency-room nurse caring for a trauma patient. Your patient has the following arterial blood gas results: pH 7.26, PaCO 2 28, HCO 3 11 mEq/L. How would you interpret these results? A. Respiratory acidosis with no compensation B. Metabolic alkalosis with a compensatory alkalosis C. Metabolic acidosis with no compensation D. Metabolic acidosis with partial compensation

D.

Four hours after mechanical ventilation is initiated, a patient's arterial blood gas (ABG) results include a pH of 7.51, PaO2 of 82 mm Hg, PaCO2 of 26 mm Hg, and HCO3- of 23 mEq/L (23 mmol/L). A. increase the FIO2. B. increase the tidal volume C. increase the respiratory rate. D. decrease the respiratory rate

D. The patient's PaCO2 and pH indicate respiratory alkalosis caused by too high a respiratory rate. The PaO2 is appropriate for a patient with COPD and increasing the respiratory rate and tidal volume would further lower the PaCO2.

When monitoring the effectiveness of treatment for a patient with a large anterior wall myocardial infarction, the most pertinent measurement for the nurse to obtain is? A. central venous pressure (CVP) B. systemic vascular resistance (SVR). C. pulmonary vascular resistance (PVR). D. pulmonary artery wedge pressure (PAWP)

D. PAWP reflects left ventricular end diastolic pressure (or left ventricular preload) and is a sensitive indicator of cardiac function. Because the patient is high risk for left ventricular failure, the PAWP must be monitored. An increase will indicate left ventricular failure. The other values would also provide useful information, but the most definitive measurement of changes in cardiac function is the PAWP.

A critical care nurse is assessing a client's plasma lactate concentration. Which result would lead the nurse to suspect that the client is experiencing lactic acidosis? A. 2.9 mEq/L B. 3.3 mEq/L C. 4.0 mEq/L D. 4.7 mEq/L

D. The lactic acid level represents the end product of anaerobic metabolism used by the body during times of insufficient oxygen supply. Lactic acidosis is generally considered to be present if the plasma lactate concentration is greater than 4 to 5 mEq/L.