APEX Unit 1 – Respiratory Questions
And Verified Answers
\.-Which muscles tense and relax the vocal cords? - Answer--Cricothyroid: "Cords Tense"
(enlongate)
-Thyroarytenoid: "They Relax" (shorten)
\.Contrast the location and function of the central and peripheral chemoreceptors. - Answer-
Central Chemoreceptor
-Located in the medulla
-Responds to the H+ concentration in the CSF (a function of the PaCO2 in blood)
Peripheral Chemoreceptors
-Located in the carotid bodies (Nerves of Hering - Glossopharyngeal n.)
-Located in the aortic arch (Vagus n.)
-Respond to decreased O2, increased CO2, and increased H+
\.Contrast the maximum recommended cuff pressures for an endotracheal tube vs. LMA. -
Answer--ETT < 25 mmHg
-LMA < 60 mmHg
\.Contrast the maximum recommended peak inspiratory pressures for an LMA-Unique vs LMA-
Proseal vs LMA-Supreme. - Answer--LMA-Unique = < 20 cmH2O
-LMA-ProSeal = < 30 cmH2O
-LMA-Supreme = < 30 cmH2O
,\.Define pulmonary hypertension and discuss the goals of anesthetic management. - Answer--
Pulmonary hypertension = Mean PAP > 25 mmHg
-Causes: COPD, left sided heart disease
-Goals: Optimize PVR
\.Define restrictive lung disease. - Answer-Characterized by:
-Impaired lung expansion
-Decreased lung volumes
-Normal pulmonary flow rates
\.Define the 4 types of dead space - Answer--Anatomic Vd: Air confined to the conducting
airways
-Alveolar Vd: Alveoli that are ventilated but not perfused
-Physiologic Vd: Anatomic Vd + Alveolar Vd
-Apparatus Vd: Vd added by equipment
\.Define the alveolar gas equation - Answer-PAO2 = FiO2 x (Pb - PH2O) - (PaCO2/RQ)
-Pb = Atmospheric pressure (760 mmHg at sea level)
-PH2O = 47 mmHg
-RQ = Respiratory quotient = 0.8
, Normal = 105.98 mmHg
\.Define the West zones of the lung - Answer-Zone I
-PA > Pa > Pv
-Dead space - ventilation without perfusion
Zone II
-Pa > PA > Pv
-Waterfall - normal physiology
Zone III
-Pa > Pv > PA
-Shunt - perfusion without ventilation
Zone IV
-Pa > Pist > Pv > PA
-Pressure in the interstitial space impairs ventilation and perfusion
\.Describe how the respiratory muscles function during the breathing cycle - Answer-Inspiration
-Diaphragm and external intercostals contract
-Accessory muscles include the sternocleidomastoid and scalene muscles
Expiration
-Exhalation is usually passive
And Verified Answers
\.-Which muscles tense and relax the vocal cords? - Answer--Cricothyroid: "Cords Tense"
(enlongate)
-Thyroarytenoid: "They Relax" (shorten)
\.Contrast the location and function of the central and peripheral chemoreceptors. - Answer-
Central Chemoreceptor
-Located in the medulla
-Responds to the H+ concentration in the CSF (a function of the PaCO2 in blood)
Peripheral Chemoreceptors
-Located in the carotid bodies (Nerves of Hering - Glossopharyngeal n.)
-Located in the aortic arch (Vagus n.)
-Respond to decreased O2, increased CO2, and increased H+
\.Contrast the maximum recommended cuff pressures for an endotracheal tube vs. LMA. -
Answer--ETT < 25 mmHg
-LMA < 60 mmHg
\.Contrast the maximum recommended peak inspiratory pressures for an LMA-Unique vs LMA-
Proseal vs LMA-Supreme. - Answer--LMA-Unique = < 20 cmH2O
-LMA-ProSeal = < 30 cmH2O
-LMA-Supreme = < 30 cmH2O
,\.Define pulmonary hypertension and discuss the goals of anesthetic management. - Answer--
Pulmonary hypertension = Mean PAP > 25 mmHg
-Causes: COPD, left sided heart disease
-Goals: Optimize PVR
\.Define restrictive lung disease. - Answer-Characterized by:
-Impaired lung expansion
-Decreased lung volumes
-Normal pulmonary flow rates
\.Define the 4 types of dead space - Answer--Anatomic Vd: Air confined to the conducting
airways
-Alveolar Vd: Alveoli that are ventilated but not perfused
-Physiologic Vd: Anatomic Vd + Alveolar Vd
-Apparatus Vd: Vd added by equipment
\.Define the alveolar gas equation - Answer-PAO2 = FiO2 x (Pb - PH2O) - (PaCO2/RQ)
-Pb = Atmospheric pressure (760 mmHg at sea level)
-PH2O = 47 mmHg
-RQ = Respiratory quotient = 0.8
, Normal = 105.98 mmHg
\.Define the West zones of the lung - Answer-Zone I
-PA > Pa > Pv
-Dead space - ventilation without perfusion
Zone II
-Pa > PA > Pv
-Waterfall - normal physiology
Zone III
-Pa > Pv > PA
-Shunt - perfusion without ventilation
Zone IV
-Pa > Pist > Pv > PA
-Pressure in the interstitial space impairs ventilation and perfusion
\.Describe how the respiratory muscles function during the breathing cycle - Answer-Inspiration
-Diaphragm and external intercostals contract
-Accessory muscles include the sternocleidomastoid and scalene muscles
Expiration
-Exhalation is usually passive
