SICU DRUGS

What is the clinical significance of the steep slope of the Starling curve relating end-diastolic volume to cardiac output?

What factors influence the oxygen content of whole blood?

What factors influence mixed venous oxygen saturation?

What lab test for tissue ischemia is based on the shift from aerobic to anaerobic metabolism?

Chapter 65 / Surgical Intensive Care 483

Demonstrates the importance of preload in determining cardiac output

Oxygen content is composed largely of that oxygen bound to hemoglobin, and is thus determined by the hemoglobin concentration and the arterial oxygen saturation; the partial pressure of oxygen dissolved in plasma plays a minor role

Oxygen delivery (hemoglobin concentration, arterial oxygen saturation, cardiac output) and oxygen extraction by the peripheral tissues

Serum lactic acid levels

At high shunt fractions, what is the effect of increasing FiO2 on arterial PO2?

At high shunt fractions ( 50%), changes in FiO2 have almost no effect on arterial PO2 because the blood that does “see” the O2 is already at maximal O2 absorption; thus, increasing the FiO2 has no effect (FiO2 can be minimized to prevent oxygen toxicity)

What does the classic chest x-ray look like with ARDS?

How can you remember the PaO2 to FiO2, or PF, ratio?

At what concentration does O2 toxicity occur?

What are the ONLY ventilatory parameters that have been shown to decrease mortality in ARDS patients?

Bilateral fluffy infiltrates

Think: “PUFF” ratio: PF ratio PaO2 : FiO2 ratio

FiO2 of 60% 48 hours; thus, try to keep FiO2 below 60% at all times

Low tidal volumes ( 6 cc/kg) and low plateau pressures 30

What are the main causes of carbon dioxide retention?

Hypoventilation, increased dead space ventilation, and increased carbon dioxide production (as in hypermetabolic

states)

Why are carbohydrates minimized in the diet/TPN of patients having difficulty with hypercapnia?

Respiratory Quotient (RQ) is the ratio of CO2 production to O2 consumption and is highest for carbohydrates (1.0) and lowest for fats (0.7)

Why are indwelling arterial lines used for blood pressure monitoring in critically ill patients?

Because of the need for frequent measurements, the inaccuracy of frequently repeated cuff measurements, the inaccuracy of cuff measurements in hypotension, and the need for frequent arterial blood sampling/labs

Which pressures/values are obtained from a Swan-Ganz catheter?

CVP, PA pressures, PCWP, CO, PVR, SVR, mixed venous O2 saturation