PREDICTION OF OXYGEN CONSUMPTION BY PULMONARY MINUTE VENTILATION.
Contributors: Indiana University School of Nursing.
Published: 1987
Number of pages: 131
Subjects: Health Sciences, Nursing.
Description: The purpose of this study was to investigate the ability of pulmonary minute ventilation (Ve) to predict systemic oxygen consumption (VO$\sb2$) in an acutely ill population. According to the theory of breathing, Ve and its primary component Va are determined by carbon dioxide production (VCO$\sb2$). VCO$\sb2$ is indirectly regulated by VO$\sb2$ through substrate catabolism. An indirect, yet definite relationship between minute ventilation and oxygen consumption should result in parallel behavior for both variables.

The hypotheses were that there would be no significant correlations between VCO$\sb2$:Va, VCO$\sb2$:Ve, VO$\sb2$:Va and VO$\sb2$:Ve. Measurement of variables was obtained from 60 subjects receiving some mechanical ventilation support. Variable measurement on subjects receiving mechanical ventilation are prone to error in gas analysis. The respiratory quotient (R.Q.) was analyzed on all subjects to determine potential gas analysis errors. Twelve (12) subjects were dropped from the study due to R.Q. values incompatible with accurate gas analysis.

Regression was employed to test the null hypothesis. The coefficient for VCO$\sb2$:Va was.71, VCO$\sb2$:Ve.69, VO$\sb2$:Va.67 and VO$\sb2$:Ve.68. Null hypotheses were rejected based on these coefficients. The coefficients were lower, however, than previously reported in studies involving healthy subjects. Regression residuals were examined for potential patterns in the population explaining the lower coefficients. Apparently two groups of subjects were present: those with lung disease and those without. A linear pattern was evident for subjects without lung disease producing a VO$\sb2$:Ve coefficient of.75 and VCO$\sb2$:Va of.84. Coefficients for subjects with lung disease were in the low.50's. The VCO$\sb2$:Va coefficient for the subgroup without lung disease was significantly higher than the subgroup with lung disease. Despite variations in coefficients between groups, coefficients were high enough to support the theory of breathing. Although null hypotheses were rejected, this study produced more questions than answers. Study results indicate oxygen consumption can be estimated by pulmonary minute ventilation but needs further study before applied to clinical situations. Further investigation should involve investigating variables which alter normal respiratory control mechanisms.
Notes: Source: Dissertation Abstracts International, Volume: 49-08, Section: B, page: 3099.

Thesis (D.N.S.)--INDIANA UNIVERSITY SCHOOL OF NURSING, 1987.

School code: 0815.