81964
document
The effect of patient position on the reproducibility of cardiac output measurements . OBJECTIVE To determine the effect of patient position on the reproducibility of cardiac output measurements . DESIGN Prospective , two-group quasi-experimental design . Convenience sample . SETTING The study involved two intensive care units in two adult acute care hospitals . PATIENTS Thirty patients admitted to the intensive care unit who had a thermodilution pulmonary artery catheter in place . Ages ranged from 39 to 80 years ( mean of 66.4 +/- 11.3 years ) . OUTCOME MEASURES Thermodilution cardiac output measurements . INTERVENTION The subjects were placed in one of two groups , initially by flipping a coin then into alternate groups . Group A subjects were placed supine , and after 5 minutes had cardiac output measurements performed . They were then placed in the 45-degree upright position , and after an additional 5 minutes had cardiac output measurements performed . Group B subjects were first placed in the 45-degree upright position , and after 5 minutes had cardiac output measurements performed . They were then placed in the supine flat position , and after an additional 5 minutes had cardiac output measurements performed . RESULTS Seventy percent ( n = 30 ) of the sample population displayed a lower cardiac output in the 45-degree upright position than that obtained in the supine position , with the decrease ranging from 1 % to 32 % ( mean decrease 11 % ) . Forty percent ( n = 30 ) of cardiac output measurements obtained in the 45-degree upright were greater than or equal to 10 % less than those obtained in the supine flat position . The differences in cardiac output were analyzed with the paired t test . which produced a 95 % confidence interval from -0.539 to -0.083 . The two-group Wilcoxon test was used to analyze the mean cardiac output with the patient in the supine , flat position and in the 45-degree upright position . The mean cardiac output at 0 degrees was found to be statistically significant higher ( p = 0.0083 ) than the mean cardiac output at 45 degrees . The effect of coexisting variables was analyzed with the Kruskal-Wallis . The use of vasoconstrictors was the only variable that had a statistically significant change in cardiac output associated with a change in position . CONCLUSIONS These results indicate that cardiac output measurements are affected by alterations in patient position . To ensure accurate comparisons between consecutive cardiac output measurements , the researchers recommend that the position in which the cardiac output measurements are performed be documented and the cardiac output measurements be conducted in a uniform position .
81965
Intervention_Physical
patient position
81966
Intervention_Physical
supine
81967
Intervention_Physical
45-degree upright position
81968
Intervention_Physical
45-degree upright position
81969
Intervention_Physical
supine flat position
81970
Outcome_Physical
lower cardiac output
81971
Outcome_Physical
cardiac output measurements
81972
Outcome_Physical
differences in cardiac output
81973
Outcome_Physical
mean cardiac output
81974
Outcome_Physical
mean cardiac output
81975
Outcome_Physical
cardiac output
81976
Participant_Sample-size
Thirty
81977
Participant_Condition
thermodilution pulmonary artery catheter
81978
Participant_Age
39 to 80