Clinical Application of the Oxyhemoglobin Dissociation Curve

•What happens to the following variables in this patient (w/ polycythemia) and why? • 1. Hemoglobin concentration (grams per volume of blood) • 2. Arterial PaO2 • 3. Hemoglobin % O2 saturation • 4. Total Blood O2 Content • 5. A-a gradient

1. Hemoglobin concentration (grams per volume of blood) -Increase 2. Arterial PaO2 -normal 3. Hemoglobin % O2 saturation - normal 4. Total Blood O2 Content -increase 5. A-a gradient -normal

In this patient (w/ polycythemia) what would a pulmonary function test reveal with respect to diffusing capacity for carbon monoxide across the alveolar-capillary interface? • 1. Increased diffusing capacity • 2. Decreased diffusing capacity • 3. Unchanged diffusing capacity • 4. Unchanged or possibly increased depending on the severity of the disease

4. Unchanged or possibly increased depending on the severity of the disease -if number 4 was not given as an answer choice the #1 would be correct

Clinical Case #3 •A family of 4 was brought in by Ambulance during a 5-day long snowstorm in Houston. The father called 911 and reports that his two children complain of lightheadedness, headaches, vomiting and are now difficult to arouse. His wife has also started vomiting and he now feels confused . The 911 operator reported that the caller too seemed confused on the phone. Paramedics report the family was unconscious on arrival and a propane BBQ was burning inside the home Physical Exam: •Cherry red skin -unreliable physical exam finding but a high yield buzzword. •Exclude other possible conditions. •Normally unremarkable physical exam

CO poisoning

Case 4 •A 26-year-old man presents to the ER after making a cherry smoothie. Within 10 minutes he started to feel unwell -with nausea, cramps, and headache. On arrival at the hospital his vital sings are:HR 128, BP 149/96, RR30, T 39.8 C. He has a cheery-red appearance. The Nurse notes that his breath smells like bitter almonds Diagnosis?

Cyanide poisoning

What is the major and most complication of Polycythemia?

Excessive blood clotting

Clinical Case # 1 •A 38-year-old male presents to your office for results of his blood work. He was initially investigated for allergies as he develops a rash less pruritus and itchiness after a bath or shower. He has borderline hypertension, complains of headache and dizziness and has no significant family history. He also suffers from occasional nose bleeds and bleeding gums. His blood work is as follows: • Hemoglobin - 19.4 g/dL (Normal: 13.6 to 16.9) • Hematocrit - median 65 percent (Normal: 40% to 50%) • MCV - 95 (fL) (Normal: 82.5 to 98) • Platelet count - median 250,000/microL (Normal: 152000 to 324000)

Polycythemia

Clinical Case # 2 •A 19-year-old college student presents to your clinic with a 4-month history increasing fatigue, she is a vegan and has just moved into a dormitory. She finds her legs get heavy and painful when she tries to exercise and they cause her discomfort at night and becomes more dyspneic on light jogs. She is often tired and fatigued and has trouble focusing on her school-work as she has frequent headaches that do not respond to typical over the counter medications. She has no regular medications and reports that she has had heavy menstrual bleeding for the past 5 months. •On examination she appears pale, has a BMI of 19, BP is 106/60, Heart rate is 106, Sp02 is 99% Tests and Investigations? Diagnosis?

Tests and Investigations? -Blood work to take a look at red blood cell count, hematocrit, hemoglobin content, white blood cell count and mean corpuscular volume of red blood cells Diagnosis? -Anemia caused by chronic blood loss

Now that a potential diagnosis has been made, which line (A, B , or C) would best represent oxygen carrying capacity of blood in this patient and why?

Total blood oxygen content = Amount dissolved in blood + how much is bound to hemoglobin -In this patient very likely there is a decrease in hemoglobin content of the blood due to chronic blood loss. -She is anemic since the number of red blood cells are likely very low. -Therefore, less oxygen can be carried by hemoglobin per unit volume of blood. -As a result, total blood oxygen content would be decreased

Now that a diagnosis has been made, which line (A, B , or C) would best represent the total oxygen content of blood in this patient and why?

Total blood oxygen content = Amount dissolved in blood + how much is bound to hemoglobin -In this patient, we had an increase in hemoglobin content in blood. -Therefore, more oxygen can be carried per unit volume of blood. -As a result, total blood oxygen content would be increased

Is oxygen therapy an effective treatment for anemia?

no b/c there isn't enough cars to carry the O2

Anemia: What happens to the following variables in this patient and why? • 1. Hemoglobin concentration • 2. Arterial PO2 • 3. Hemoglobin O2 saturation • 4. Total Blood O2 Content • 5. A-a gradient

• 1. Hemoglobin concentration -Decrease • 2. Arterial PO2 -normal • 3. Hemoglobin O2 saturation -normal • 4. Total Blood O2 Content -decrease • 5. A-a gradient -normal

•What happens to the following variables in this patient and why? • 1. Hemoglobin concentration • 2. Arterial PO2 • 3. Hemoglobin O2 saturation • 4. Total Blood O2 Content • 5. A-a gradient

• 1. Hemoglobin concentration • 2. Arterial PO2 • 3. Hemoglobin O2 saturation • 4. Total Blood O2 Content • 5. A-a gradient *ALL OF THESE WILL BE NORMAL!

Vital Signs of CO poisoning

• Are unreliable and therefore do not aid in diagnosis or guide treatment. • Always important to assess for other possible causes and to establish a baseline

Management of CO poisoning

•ABC •High Flow 02 via non-rebreather *we want too increase PAO2 to kick out the CO from hemoglobin •Assess for possible Hyperbaric Oxygen treatment

Treatment of Cyanide poisoning

•Administer cyanide antidote when cyanide poisoning is clinically suspected. Hydroxocobalamin is the preferred antidote. • Binds Cyanide -> cyanocobalamin -> Renal Excretion •Nitrites-> oxidize Hb -> Methemoglobin -> binds cyanide cyanomethemoglobin -> less toxicity •Sodium thiosulfate -> cyanide conversion -> thiocyanate renal excretion

Routes of Cyanide Exposure

•Industrial exposures and fires •Plants and Fruits •Miscellaneous •Drugs •Combustion

Treatment of polycythemia

•Phlebotomy •Hydroxyurea •Ruxolitinib (JAK1/2 inhibitor)

What Investigations would you do for CO poisoning

•Pulse Oximetry?? (would read normal!!! Even though hemoglobin now is mostly bound to carbon monoxide and not oxygen -CO has nearly the same properties as O2 -Pulse oximetry is looking at the saturation of hemoglobin~ hemoglobin is still full (it's just bound w/ CO instead of O2) -therefore, it can't differentiate between CO and O2 •ABG/VBG (will see evidence of acidosis~ (elevated lactate) •Carboxyhemoglobin level measurement in blood •ECG and cardiac biomarkers •CT Head (bilateral globus pallidus lesions) ➢Would a typical standard pulse oximeter yield normal values in these patients? It would show a false normal

Causes of Polycythemia

•Relative -Volume Contraction Primary • Polycythemia Vera (JAK2 Mutation) • Other myeloproliferative neoplasms Secondary • Hypoxic -Pulmonary disease, right to left shunts, sleep apnea, high altitude, smoking • Autonomous EPO production -HCC, RCC, Pheocytoma, Uterine Leiomyomata Blood Doping -EPO, transfusion, anabolic steroids

Pediatrics and CO poisoning

•Signs and symptoms may not be as obvious, why? -hard to access a child (also you just assume they are cranky or tired etc. •Compared to adults, they have higher oxygen requirements and higher minute ventilation: More prone to carbon monoxide-induced cardio-respiratory failure compared to adults