Pulmonary Mechanics

Question 1

Respiratory Changes for Obese Patient

Answer 1

Decreased expiratory reserve volume, FRC and tidal volumes. RV unchanged and IRV increased. Increased closing capacity worse in supine position. Increased O2 consumption with rest and exertion. DLCO increased due to increased pulmonary blood volume.

Question 2

Arterial blood gas changes in Pregnancy

Answer 2

Arterial partial pressure of oxygen increased and arterial partial pressure of carbon dioxide decreases resulting in respiratory alkalosis. Serum bicarbonate decreases given respiratory alkalosis and base excess decreases.

Question 3

Respiratory Mechanics in Pregnancy

Answer 3

Minute ventilation increases (increase in RR and **TV) **main reason why minute ventilation increases.

Question 4

Alveolar Gas Equation

Answer 4

PAO2 = FiO2 (Patmo-PH20) - PaCO2/RQ

Question 5

TRALI (Transfusion Related Acute Lung Injury)

Answer 5

Leading cause of transfusion related death. Presents with fever, dyspnea, fluid in ETT and hypoxia within 6 hours of transfusion. Non-cardiogenic pulmonary edema. Associated with leukopenia due to agglutination of leukocytes in recipient’s blood. Treatment is supportive. Stop transfusion from donor and give other products if necessary. Associated with all components but more so with female whole blood or plasma donations.

Question 6

Jet Ventilation Advantages

Answer 6

Can be placed trans-tracheal, subglottic or supraglottic. Concern for barotrauma, air-trapping, hypercarbia and pneumothorax (due to high pressures). Subglottic- worsens visualization b/c needs special catheter, less debris in airway, better end tidal monitoring, and lower airway pressures.

Question 7

Neonatal Respiratory System

Answer 7

Decreased lung compliance (decreased alveoli and elastin) but increased chest wall compliance (more collagen in the rib cage). Increased oxygen consumption (6-9 cc/kg/min). Have high percentage of type II diaphragm fibers which fatigue quickly.

Question 8

A-a gradient

Answer 8

Normal value associated with hypoventilation and low PO2 (partial pressure of oxygen)

Question 9

Vaporizers and Changes in Altitudes

Answer 9

Variable bypass vaporizers (partial pressure does not change) but concentration increases. Desfurane concentration needs to be increased with higher altitudes (due to decreased atmospheric pressure)

Question 10

Factors that Affect Speed of Onset of Inhalational Anesthestics

Answer 10

Decreased FRC, faster induction. Increased cardiac output, slower induction.

Question 11

Predictors of Hypoxemia on OLV

Answer 11

High FEV1 (normal to restrictive lung disease), Right Side Thoracotomy, Supine positioning, High perfusion on dependent lung

Question 12

Hepatopulmonary Syndrome

Answer 12

Increased A-a gradient (increased perfusion with decreased ventilation), hypoxia worse with standing. Pulmonary vasodilation 2/2 increased nitric oxide.

Question 13

Nitrous Oxide and Lungs

Answer 13

Improves PaO2 due to vasodilation to improve perfusion and decrease dead space ventilation. Decreases platelet aggregation. Causes methemoglobinemia resulting in shift in O2 dissociation curve to the left.

Question 14

FRC = PANGOS (decreased)

Answer 14

Pregnancy, Ascites, Neonates, General Anesthesia, Obesity, Supine Position

Question 15

Peak and plateau pressures

Answer 15

Large difference between the two values = airway resistance. No significant difference between the two values = issues with compliance. Increase in plateau pressures results in decrease in compliance

Question 16

Acute Respiratory Distress Syndrome

Answer 16

Diffuse alveolar damage, increased capillary permeability, pulmonary edema,