Effect of body temperature on peripheral venous pressure measurements and its agreement with central venous pressure in neurosurgical patients.

Previous studies suggest a correlation of central venous pressure (CVP) with peripheral venous pressure (PVP) in different clinical settings. The effect of body temperature on PVP and its agreement with CVP in patients under general anesthesia are investigated in this study. Fifteen American Society of Anesthesiologists I-II patients undergoing elective craniotomy were included in the study. CVP, PVP, and core (Tc) and peripheral (Tp) temperatures were monitored throughout the study. A total of 950 simultaneous measurements of CVP, PVP, Tc, and Tp from 15 subjects were recorded at 5-minute intervals. The measurements were divided into low- and high-Tc and -Tp groups by medians as cutoff points. Bland-Altman assessment for agreement was used for CVP and PVP in all groups. PVP measurements were within range of +/-2 mm Hg of CVP values in 94% of the measurements. Considering all measurements, mean bias was 0.064 mm Hg (95% confidence interval -0.018-0.146). Corrected bias for repeated measurements was 0.173 +/- 3.567 mm Hg (mean +/- SD(corrected)). All of the measurements were within mean +/- 2 SD of bias, which means that PVP and CVP are interchangeable in our setting. As all the measurements were within 1 SD of bias when Tc was > or = 35.8 degrees C, even a better agreement of PVP and CVP was evident. The effect of peripheral hypothermia was not as prominent as core hypothermia. PVP measurement may be a noninvasive alternative for estimating CVP. Body temperature affects the agreement of CVP and PVP, which deteriorates at lower temperatures.

Effect of catheter site on the agreement of peripheral and central venous pressure measurements in neurosurgical patients.

STUDY OBJECTIVE: Previous studies suggest a correlation of central venous pressure (CVP) with peripheral venous pressure (PVP) in different clinical setups. The aim of this study was to investigate the effect of measurement site on PVP and its agreement with CVP in patients undergoing general anesthesia. DESIGN: Prospective randomized study. SETTINGS: University hospital. PATIENTS: Thirty patients of American Society of Anesthesiologists physical status I and II undergoing elective craniotomy. INTERVENTIONS: Patients were randomly assigned into Group A (antecubital; n=15) and Group D (dorsum hand; n=15) for antecubital and hand dorsum catheterization sites, respectively. Central venous pressure and PVP were monitored throughout the study. A total of 1925 simultaneous measurements were recorded at 5-minute intervals. Bland-Altman assessment for agreement was used for CVP and PVP in 2 groups. MEASUREMENTS: Peripheral venous pressure measurements were within the range of +/-2 mm Hg of CVP values, in 93.9% of the measurements in Group A, and in 91.2% of the measurements in Group D. Considering all measurements, mean bias was -0.072 mm Hg (95% CI, -0.134 to -0.010). Group A measurements showed a bias (CVP-PVP) of 0.173+/-3.557 mm Hg, whereas the bias was -0.122+/-4.322 mm Hg (mean+/-SDcorrected for repeated measurements) in Group D. All of the measurements were within mean+/-2SD of bias, which means that PVP and CVP are interchangeable in our clinical setting. CONCLUSION: Peripheral venous pressure measurement may be a noninvasive alternative for estimating CVP in patients undergoing elective neurosurgical operations. Measuring PVP from hand dorsum does not interfere with the agreement of CVP and PVP.