Peripheral venous pressure as a predictor of central venous pressure during orthotopic liver transplantation

STUDY OBJECTIVE: To assess the reliability of peripheral venous pressure (PVP) as a predictor of central venous pressure (CVP) in the setting of rapidly fluctuating hemodynamics during orthotopic liver transplant surgery. DESIGN: Prospective clinical trial. SETTING: UCLA Medical Center, main operating room-liver transplant surgery. PATIENTS: Nine adult patients with liver failure undergoing orthotopic liver transplant surgery. INTERVENTIONS: A pulmonary artery catheter and a 20-g antecubital peripheral intravenous catheter dedicated to measuring PVP were placed in all patients after standard general endotracheal anesthesia induction and institution of mechanical ventilation. MEASUREMENTS: Peripheral venous pressure and CVP were recorded every 5 minutes and/or during predetermined, well-defined surgical events (skin incision, venovenous bypass initiation, portal vein anastamosis, 5 minute post graft reperfusion, abdominal closure). Pulmonary artery pressure and cardiac output (via thermodilution) were recorded every 15 and 30 minutes, respectively. MAIN RESULTS: Peripheral venous pressure (mean +/- SD) was 11.0 +/- 4.5 mmHg vs a CVP of 9.5 +/- 5.0; the two measurements differed by an average of 1.5 +/- 1.6 mmHg. Peripheral venous pressure correlated highly with CVP in every patient, and the overall correlation among all nine patients calculated using a random-effects regression model was r = 0.95 (P < 0.0001). A Bland-Altman analysis used to determine the accuracy of PVP in comparison to CVP yielded a bias of -1.5 mmHg and a precision of +/-3.1 mm Hg. CONCLUSION: Our study confirms that PVP correlates with CVP even under adverse hemodynamic conditions in patients undergoing liver transplantation.     

Spurious central venous pressure

A patient is described in whom two different sites of cannulation of central veins produced markedly different pressures with potentially dangerous consequences. Falsely elevated pressures recorded from a catheter inserted via the subclavian vein were related to the patency in the arm of an arteriovenous shunt. The likely cause of this phenomenon is discussed.     

Iliac venous pressure estimates central venous pressure after laparotomy

Background

Central venous pressure (CVP) is traditionally obtained through subclavian or internal jugular central catheters; however, many patients who could benefit from CVP monitoring have only femoral lines. The accuracy of illiac venous pressure (IVP) as a measure of CVP is unknown, particularly following laparotomy.

Methods

This was a prospective, observational study. Patients who had both internal jugular or subclavian lines and femoral lines already in place were eligible for the study. Pressure measurements were taken from both lines in addition to measurement of bladder pressure, mean arterial pressure, and peak airway pressure. Data were evaluated using paired t-test, Bland-Altman analysis, and linear regression.

Results

Measurements were obtained from 40 patients, 26 of which had laparotomy. The mean difference between measurements was 2.2 mm Hg. There were no significant differences between patients who had laparotomy and nonsurgical patients (P = 0.93). Bland-Altman analysis revealed a bias of 1.63 ± 2.44 mm Hg. There was no correlation between IVP accuracy and bladder pressure, mean arterial pressure, or peak airway pressure.

Conclusions

IVP is an adequate measure of CVP, even in surgical patients who have had recent laparotomy. Measurement of IVP to guide resuscitation is encouraged in patients who have only femoral venous catheter access.     

Peripheral venous pressure predicts central venous pressure poorly in pediatric patients

Purpose: Using peripheral venous pressure (PVP) instead of central venous pressure (CVP) as a volume monitor decreases patient risks and costs, and is convenient. This study was undertaken to determine if PVP predicts CVP in pediatric patients. METHODS: With ethical approval and informed consent, 30 pediatric patients aged neonate to 12 yr requiring a central venous line were studied prospectively in a tertiary care teaching hospital. In the supine position, PVP and CVP were simultaneously transduced. Ninety-six paired recordings of CVP and PVP were made. Correlation and Bland-Altman analysis of agreement of end-expiratory measurements were performed. RESULTS: The mean (SD; range) CVP was 10.0 mmHg (6.0; -1.0 to 27.0); the mean PVP was 13.7 mmHg (6.3; 0.0 to 33.0); offset (bias) of PVP > CVP was 3.7 mmHg with SD 2.6. The 95% confidence intervals (CI) for the bias were 3.2 to 4.1 mmHg. In the Bland-Altman analysis, lower and upper limits of agreement (LOA; CI in parentheses) were -1.5 (-2.3 to -0.7) and 8.8 (8.1 to 9.6) mmHg. Eight of 96 points were outside the limits of agreement. The correlation of PVP on CVP was r = 0.92, P < 0.0001. For a subset of ten patients (20 simultaneous recordings) with iv catheters proximal to the hand, limits of agreement were better - offset: 3.8 mmHg (+/- 1.4); lower LOA: 1.2 mmHg (0.25 to 2.1); upper LOA: 6.6 mmHg (5.7 to 7.5). CONCLUSION: Peripheral venous pressure measured from an iv catheter in the hand predicts CVP poorly in pediatric patients.     

Hazards of central venous pressure monitoring

In shock syndromes, cannulation of the central veins has become standard practice. The procedure, although valuable, is not completely innocuous. Fatal complications as a result of perforation of the sinus coronarius with resultant cardiac tamponade, and a laceration of the subclavian artery are described, in addition to the previously reported complications encountered during such monitoring. It is of vital importance that the procedure be prescribed and supervised only by those who are thoroughly skilled in its use and that there be awareness of the early symptoms of cardiac tamponade when a venous catheter is in situ.     

Correlation of peripheral venous pressure and central venous pressure in kidney recipients

BACKGROUND AND OBJECTIVE: Previous studies in adults have demonstrated a clinically useful correlation between central venous pressure (CVP) and peripheral venous pressure (PVP). The current study prospectively compared CVP measurements from a central versus a peripheral catheter in kidney recipients during renal transplantation. METHODS: With ethics committee approval and informed consent, 30 consecutive kidney recipients were included in the study. We excluded patients who had significant valvular disease or clinically apparent left ventricular failure. For each of 30 patients, CVP and PVP were measured on five different occasions. The pressure tubing of the transducer system was connected to the distal lumen of the central or to the peripheral venous catheter for measurements following induction of anesthesia, after induction, 1 hour after induction, reperfusion of the kidney, and the end of the operation, yielding 150 hemodynamic data points. Each hemodynamic measurement included heart rate, mean arterial pressure, mean CVP, and mean PVP determined at end-expiration. RESULTS: The mean PVP was 13.5 +/- 1.8 mm Hg and the mean CVP was 11.0 +/- 1.5 mm Hg during surgery. The mean difference was 2.5 +/- 0.5 (P < .01). Repeated-measures analysis of variance indicated a highly significant relationship between PVP and CVP (P < .01) with a Pearson correlation coefficient of 0.97. CONCLUSION: Under the conditions of this study, PVP showed a consistently high agreement with CVP in the perioperative period among patients without significant cardiac dysfunction.     

Correlation of peripheral venous pressure and central venous pressure in surgical patients

OBJECTIVE: To determine the degree of agreement between central venous pressure (CVP) and peripheral venous pressure (PVP) in surgical patients. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Patients without cardiac dysfunction undergoing major elective noncardiac surgery (n = 150). MEASUREMENTS AND MAIN RESULTS: Simultaneous CVP and PVP measurements were obtained at random points in mechanically ventilated patients during surgery (n = 100) and in spontaneously ventilating patients in the postanesthesia care unit (n = 50). In a subset of 10 intraoperative patients, measurements were made before and after a 2-L fluid challenge. During surgery, PVP correlated highly to CVP (r = 0.86), and the bias (mean difference between CVP and PVP) was -1.6 +/- 1.7 mmHg (mean +/- SD). In the postanesthesia care unit, PVP also correlated highly to CVP (r = 0.88), and the bias was -2.2 +/- 1.9 (mean +/- SD). When adjusted by the average bias of -2, PVP predicted the observed CVP to within +/-3 mmHg in both populations of patients with 95% probability. In patients receiving a fluid challenge, PVP and CVP increased similarly from 6 +/- 2 to 11 +/- 2 mmHg and 4 +/- 2 to 9 +/- 2 mmHg. CONCLUSION: Under the conditions of this study, PVP showed a consistent and high degree of agreement with CVP in the perioperative period in patients without significant cardiac dysfunction. PVP -2 was useful in predicting CVP over common clinical ranges of CVP. PVP is a rapid noninvasive tool to estimate volume status in surgical patients.