contractile proteins within the cardiac myocytes. As a result, stroke volume in neonates remains almost the same, de- creasing the likelihood of increasing cardiac output with an increase in preload. Below are some definitions Singh noted. Definitions Cardiac Output (CO): volume of blood pumped by each ventricle in one minute. CO = stroke volume x heart rate Heart Rate (HR): number of beats per minute. • Stroke Volume (SV): volume (ml) of blood pumped out of the left ventricle with each beat. Preload: the force that stretches the cardiac muscle prior to contraction; associated with the volume of blood that fills the heart from venous return. ⚫ Afterload: the amount of pressure that the heart needs to eject the blood during ventricular contraction. Minute Ventilation (Total Ventilation): the amount of air that enters the lungs per minute. Minute ventilation respiratory rate x tidal volume ⚫Tidal volume: the normal volume (ml) of air inspired and expired with each breath. Respiratory Rate: the number of breaths per minute. Alveolar Ventilation (AV): represents actual ventilation as it considers dead space. It represents the volume of air within the respiratory zone available for gas exchange per minute. AV respiratory rate x (tidal volume - dead space) ⚫ Dead Space: the air in the conducting zones. Pulmonary Capillary Perfusion (Q): the flow of blood to pulmonary capillaries. Questions 11. How can neonates increase cardiac output if stroke volume remains the same? 12. a. Using one of the heart malformations, explain what would happen to heart rate. b. Pavit had normal biventricular contractility. Assuming stroke volume remained static, would cardiac output be affected? Explain using one of the malformations. 13. Pavit was panting, indicating his respiratory rate had increased. How would this affect: a. tidal volume? b. alveolar ventilation? 14. Would pulmonary capillary perfusion be affected by increased blood being received by the right ventricule? Explain. 15. a. Would alveolar ventilation and pulmonary capillary perfusion affect gas exchange? b. Based on your responses to Questions 13 and 14, would gas exchange be increased or decreased in Pavit? Based on further discussions with Paul and conducting some literature research, Singh understood that sufficient cardiac output is vital in maintaining normal body function due to sufficient tissue perfusion and oxygenation. Therefore, the respiratory system is intimately linked to the cardiovascular system. He noted that two factors that affect the respiratory exchange of gases are the changes to blood flow and the surface area of alveoli. In addition, he learned that to meet the high metabolic oxygen needs of a newborn, the myocardium contractility is at its maximum. In addition, the myocar- dium is less compliant due to the disorderly organization of the higher amount of non-contractile proteins compared to

contractile proteins within the cardiac myocytes. As a result, stroke volume in neonates remains almost the same, de- creasing the likelihood of increasing cardiac output with an increase in preload. Below are some definitions Singh noted. Definitions Cardiac Output (CO): volume of blood pumped by each ventricle in one minute. CO = stroke volume x heart rate Heart Rate (HR): number of beats per minute. • Stroke Volume (SV): volume (ml) of blood pumped out of the left ventricle with each beat. Preload: the force that stretches the cardiac muscle prior to contraction; associated with the volume of blood that fills the heart from venous return. ⚫ Afterload: the amount of pressure that the heart needs to eject the blood during ventricular contraction. Minute Ventilation (Total Ventilation): the amount of air that enters the lungs per minute. Minute ventilation respiratory rate x tidal volume ⚫Tidal volume: the normal volume (ml) of air inspired and expired with each breath. Respiratory Rate: the number of breaths per minute. Alveolar Ventilation (AV): represents actual ventilation as it considers dead space. It represents the volume of air within the respiratory zone available for gas exchange per minute. AV respiratory rate x (tidal volume - dead space) ⚫ Dead Space: the air in the conducting zones. Pulmonary Capillary Perfusion (Q): the flow of blood to pulmonary capillaries. Questions 11. How can neonates increase cardiac output if stroke volume remains the same? 12. a. Using one of the heart malformations, explain what would happen to heart rate. b. Pavit had normal biventricular contractility. Assuming stroke volume remained static, would cardiac output be affected? Explain using one of the malformations. 13. Pavit was panting, indicating his respiratory rate had increased. How would this affect: a. tidal volume? b. alveolar ventilation? 14. Would pulmonary capillary perfusion be affected by increased blood being received by the right ventricule? Explain. 15. a. Would alveolar ventilation and pulmonary capillary perfusion affect gas exchange? b. Based on your responses to Questions 13 and 14, would gas exchange be increased or decreased in Pavit? Based on further discussions with Paul and conducting some literature research, Singh understood that sufficient cardiac output is vital in maintaining normal body function due to sufficient tissue perfusion and oxygenation. Therefore, the respiratory system is intimately linked to the cardiovascular system. He noted that two factors that affect the respiratory exchange of gases are the changes to blood flow and the surface area of alveoli. In addition, he learned that to meet the high metabolic oxygen needs of a newborn, the myocardium contractility is at its maximum. In addition, the myocar- dium is less compliant due to the disorderly organization of the higher amount of non-contractile proteins compared to