During exercise, what is the primary mechanism for increased oxygen delivery to active muscles?
ADecreased blood viscosity
BIncreased cardiac output
CIncreased hemoglobin affinity
DEnhanced oxygen diffusion
A 19-year-old man presents to the clinic with a complaint of increasing shortness of breath for the past 2 years. His shortness of breath is associated with mild chest pain and occasional syncopal attacks during strenuous activity. There is no history of significant illness in the past, however, one of his uncles had similar symptoms when he was his age and died while playing basketball a few years later. He denies alcohol use, tobacco consumption, and the use of recreational drugs. On examination, pulse rate is 76/min and is regular and bounding; blood pressure is 130/70 mm Hg. A triple apical impulse is observed on the precordium and a systolic ejection crescendo-decrescendo murmur is audible between the apex and the left sternal border along with a prominent fourth heart sound. The physician then asks the patient to take a deep breath, close his mouth, and pinch his nose and try to breathe out without allowing his cheeks to bulge out. In doing so, the intensity of the murmur increases. Which of the following hemodynamic changes would be observed first during this maneuver?
A↓ Mean Arterial Pressure, ↑ Heart rate, ↑ Baroreceptor activity, ↓ Parasympathetic Outflow
B↑ Mean Arterial Pressure, ↓ Heart rate, ↑ Baroreceptor activity, ↑ Parasympathetic Outflow
C↑ Mean Arterial Pressure, ↓ Heart rate, ↓ Baroreceptor activity, ↑ Parasympathetic Outflow
D↑ Mean Arterial Pressure, ↑ Heart rate, ↓ Baroreceptor activity, ↓ Parasympathetic Outflow
E↑ Mean Arterial Pressure, ↑ Heart rate, ↑ Baroreceptor activity, ↑ Parasympathetic Outflow
A 27-year-old man is brought to the emergency department 30 minutes after being shot in the abdomen during a violent altercation. His temperature is 36.5°C (97.7°F), pulse is 118/min and regular, and blood pressure is 88/65 mm Hg. Examination shows cool extremities. Abdominal examination shows a 2.5-cm entrance wound in the left upper quadrant at the midclavicular line, below the left costal margin. Focused ultrasound shows free fluid in the left upper quadrant. Which of the following sets of hemodynamic changes is most likely in this patient? Cardiac output (CO) | Pulmonary capillary wedge pressure (PCWP) | Systemic vascular resistance (SVR) | Central venous pressure (CVP)
A↑ ↓ ↓ ↓
B↓ ↓ ↑ ↑
C↓ ↓ ↓ ↓
D↓ ↓ ↑ ↓
E↓ ↑ ↑ ↑
+ 7 more in the PDF
Browse all chapters