Effect of Head of Bed Position on Pulmonary Artery Pressure Measurements: A Review of the Literature

Abstract Background The Doppler effect has allowed the characterization of several vessels in maternal-fetal circulation that have been used for practical purposes. Our review of the literature showed a paucity of information about fetal pulmonary artery pressure (FMPAP) and its behavior in regard to gestational age (GA). The objectives of the study were to evaluate a formula to calculate the main FMPAP and its correlation with GA. Methods A total of 337 fetuses without obvious pathology were studied prospectively using Doppler evaluation of the FMPAP. Using the fetal main pulmonary artery Doppler acceleration time (FMPAT), we obtained the FMPAP using the following formula: FMPAP=90 – (0.62×FMPAT). Regression analyses, Pearson’s bivariate correlation and paired sample t-test were used when appropriate. Results FMPAT increases while FMPAP decreases with GA. Pearson’s correlation coefficient for FMPAP and GA was −0.544 (P-value<0.001) and for FMPAT and GA was 0.556 (P-value<0.001). FMPAP and FMPAT were highly correlated (R=−0.972; P<0.001). Conclusion Pulmonary artery pressure in the fetus decreases with GA.

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A stabilization period of 5 minutes is adequate when measuring pulmonary artery pressures after turning

American Journal of Critical Care ◽

10.4037/ajcc1993.2.6.474 ◽

1993 ◽

Vol 2 (6) ◽

pp. 474-477 ◽

Cited By ~ 2

Author(s):

PA Shinners ◽

MO Pease

Keyword(s):

Pulmonary Artery ◽

Pulmonary Artery Pressure ◽

Supine Position ◽

Surgical Intensive Care Unit ◽

Pressure Measurements ◽

Artery Pressure ◽

Group A ◽

Group B ◽

The Right ◽

Stabilization Period

OBJECTIVE: To compare hemodynamic measurements made before turning and at 5 and 30 minutes after turning, and to determine whether the stabilization period affects the difference between supine and side-lying pulmonary artery pressures. METHODS: This study was performed in the cardiothoracic surgical intensive care unit of a midwestern university hospital. The 31 postoperative open-heart surgical patients, 26 men and 5 women aged 41 to 76 years (64 +/- 9.3, mean +/- SD) with pulmonary artery catheters in place, were divided into two groups to compare supine to side-lying pressures and the time intervals between the position changes. The supine-first subjects (Group A) were placed in the supine position for baseline measurements and turned to either the right or left side-lying position for the 5- and 30-minute pulmonary artery pressure measurements. The side-first subjects (Group B) were placed in either the right or left side-lying position for baseline measurements and then in the supine position for the 5- and 30-minute pulmonary artery pressure measurements. RESULTS: Pulmonary artery pressures, heart rate and arterial pressure were not significantly different at 5 and 30 minutes. Supine pulmonary artery pressures in Group A were not significantly different from supine pressures in Group B. Side-lying pulmonary artery pressures in Group A were not significantly different from side-lying pressures in Group B. Side-lying vs supine pulmonary artery pressures were significantly different in both Group A and Group B. CONCLUSION: The current practice of turning and settling the patient, zeroing the transducer and proceeding to make the pulmonary artery pressure readings appears to be valid. The stabilization period after turning does not explain the differences found between side-lying and supine pulmonary artery pressures.

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