Room-temperature thermodilution cardiac output. Central venous vs side port.

OBJECTIVE: To assess the accuracy of room-temperature thermodilution cardiac output measurements from the side port (SP) of the introducer catheter through which the pulmonary artery flotation catheter is inserted. DESIGN: Central venous port (CVP) cardiac output measurements were compared with SP cardiac output measurements using the same right-heart catheter. SETTING: The general intensive care unit of the Hospital for Joint Diseases, Orthopedic Institute, New York. PATIENTS: Thirty one orthopedic patients with 31 different right-heart catheters placed in the right internal jugular or right subclavian position were evaluated. INTERVENTION: Four injections of 10 ml of normal saline solution at room temperature were made through each port; the results of the last three injections were averaged. Cardiac output determinations from both ports were completed in less than 10 min. The order of port injection was random. RESULTS: A significant difference was noted between cardiac output determinations from the two ports (p < 0.001, paired Student's t test) with the SP slightly overestimating thermodilution cardiac outputs by 6.34 +/- 8.38 percent compared to the CVP. A significant correlation was noted between both ports (r = 0.97, p < 0.001) with the linear regression line starting at the origin (y intercept not significantly different from zero) with a slope (1.07) significantly greater than 1. CONCLUSION: If the proximal CVP becomes nonfunctional, room-temperature thermodilution cardiac outputs from the SP can be used with the understanding that a slight overestimation of cardiac output will occur.

Spiral CT diagnosis of pulmonary embolus.

With the advent of new diagnostic techniques such as the spiral computed tomography angiogram, the sequence of tests needed to diagnose a pulmonary embolus may be more efficient if the testing behavior is tailored to the patient's underlying cardiopulmonary status. This may be particularly important if the patient is elderly or has other reasons for limited cardiopulmonary reserve. We report several cases with a new sequence of testing behavior.

The normal difference in bilateral indirect blood pressure recordings in normotensive individuals.

If there is a significant dichotomy between bilateral blood pressure determinations in both arms, it is often taken as a sign of some type of underlying pathology. We wished to evaluate what the normal variation might be for significant differences between blood pressures in both arms. Significant difference was arbitrarily chosen as a systolic blood pressure value greater than 10 mm Hg. Bilateral indirect blood pressure determinations were obtained in 100 subjects with no known history of hypertension in the sitting position. The blood pressure was obtained by 2 observers, one who recorded the systolic and diastolic blood pressure as announced by the person taking the blood pressures who was blinded to the actual values taken. The coefficient of variation in obtaining the blood pressures in each arm was determined in 5 of the 100 subjects. The age, sex, and handedness of each individual were recorded as demographic variables. The average left and right systolic blood pressures were 112.1 +/- 16.5 and 112.7 +/- 16.3 mm Hg, respectively. The average left and right diastolic pressures were 64.4 +/- 11.6 and 63.5 +/- 9.9 mm Hg, respectively. There was no significant difference between left minus right systolic or diastolic differences (Student's paired t-test). There were no significant differences in systolic or diastolic blood pressure between gender or between right and left handed individuals (non-paired t-test). The average coefficients of variation for right and left arm systolic blood pressures were 5.41% and 5.81%, respectively. Fifteen subjects had differences in systolic blood pressure between both arms exceeding 10 mm Hg (7% to 22%, 95% confidence interval). Differences of more than 10 mm Hg in indirect bilateral blood pressure recordings are frequent in normotensive individuals and probably do not per se indicate any abnormal pathology. In the right clinical situation, differences that are noted should probably be repeated and should be added to the total clinical picture when used to determine whether a pathologic condition is present.