Start with a subjective assessment of skin temperature to identify hypoperfusion in intensive care unit patients

To determine whether physical examination alone or in combination with biochemical markers can accurately diagnose hypoperfusion.

Data from 264 consecutive surgical intensive care unit patients were collected by two intensivists and included extremity temperature, vital signs, arterial lactate, arterial blood gases, hemoglobin, and pulmonary artery catheter values with derived indices. Days of data were divided into data collected from patients with cool extremities (cool skin temperature [CST] group) versus warm extremities (warm skin temperature [WST] group). Values are means +/- SD. Comparisons between groups were made by two-tailed unpaired t test; significance was assumed for p < or = 0.05.

There were 328 days of observations in the CST group versus 439 in the WST group. There were no differences (p > 0.05) between CST and WST data with regard to heart rate (107 +/- 14 vs. 99 +/- 19 beats/min), systolic blood pressure (118 +/- 24 vs. 127 +/- 28 mm Hg), diastolic blood pressure (57 +/- 14 vs. 62 +/- 15 mm Hg), pulmonary artery occlusion pressure (14 +/- 6 vs. 16 +/- 5 mm Hg), Fio2 (0.48 +/- 0.7 vs. 0.45 +/- 0.2), hemoglobin (8.8 +/- 1.6 vs. 9.3 +/- 1.3 g/dL), Pco2 (44.3 +/- 11.8 vs. 40.7 +/- 9.2 mm Hg), or Po2 (96.4 +/- 12.6 vs. 103.8 +/- 22.2 mm Hg). However, cardiac output (5.3 +/- 2.2 vs. 8.2 +/- 2.6 L/min), cardiac index (2.9 +/- 1.2 vs. 4.3 +/- 1.2 L/min/m2), pH (7.32 +/- 0.2 vs. 7.39 +/- 0.07), TCO2 (19.5 +/- 3.1 vs. 25.1 +/- 4.8 mEq/L), and Svo2 (60.2 +/- 4.4% vs. 68.2 +/- 7.8%) were all significantly lower (p < 0.05) in CST patients compared with WST patients. By comparison, lactate (4.7 +/- 1.5 vs. 2.2 +/- 1.6 mmol/L, p < 0.05) was significantly elevated in patients with cool extremities.

Combining physical examination with serum bicarbonate and arterial lactate identifies patients with hypoperfusion as defined by low Svo2 and cardiac index. Hypoperfusion may occur despite supranormal cardiac indices. Patients with cool extremities and elevated lactate levels may benefit from a pulmonary artery catheter to guide but not initiate therapy.