Sechrist, Karen R.
M.S. (Master of Science)
School of Nursing
Head; Blood pressure--Measurement; Patients--Positioning
Measurement of pulmonary artery pressures (PAP) through a flow- directed, balloon-tipped catheter provides important data to guide the therapy of critically ill patients. While it is common practice to position the patient supine and flat (0°) for these measurements, many patients do not tolerate this position. All patients are awakened or otherwise disrupted when the measurements are done hourly, or more often. This study assesses the effect of a 30° head elevation on the PAP measurement utilizing the phlebostatic axis as a reference level for adjustment of the transducer. Twenty-four patients have been studied in the critical care units of one hospital through the use of a quasi- experimental design, consisting of a randomized, two-way crossover. A patient was randomly placed in one of the two positions (0°, 30°) for a period of two minutes while the transducer was set at the phlebostatic axis and the system was calibrated to atmospheric level. The patient was then placed in the alternate position for two minutes while the system was recalibrated for that position. Two measuring tools, a carpenter's level and a fixed angle, were used to ensure transducer placement at the phlebostatic axis and an accurate 30° angle, respectively. Systolic (PAS), diastolic (PAD), and mean (PAM) pulmonary artery pressure measurement (in mmHg) were observed and recorded from the visual read-out and analog recorder. When variation in pressures occurred with respiration, PAS, PAD, and PAM were computed by taking the mean of the pressures recorded during one respiratory cycle. One representative wave form was selected for measurement in the event that respiratory variation did not occur. PAM was computed using the formula 2/3 PAD + 1/3 PAS. Statistical analysis of the data indicates that no significant difference (P>.50) exists between the two positions in any parameter measured. Results indicate that reliable pressures are obtained at a 30° head-elevated position which may obviate the need for placing the patient in a flat, supine position for PAP measurements.
Bramschreiber, Julie K., "Effect of head elevation on pulmonary artery pressure measurement" (1984). Graduate Research Theses & Dissertations. 2728.
Northern Illinois University
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