A comparison of infusion volumes in the measurement of intra-abdominal pressure.

Bladder pressure measurement through a foley catheter is the current standard in monitoring for intraabdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Accurate pressure transduction requires a continuous fluid column with a small volume of transducing medium at the tip of the catheter. Infusing excessive fluid volume can falsely elevate the measured intra-abdominal pressure (IAP) due to bladder overdistention and can lead to intrinsic muscular contraction. This effect can be seen with volumes as low as 60 mL. Recent expert consensus has recommended 25 mL as the maximal infusion volume; however, 50 mL is the most commonly cited volume of infusion in the literature. The purpose of this analysis was to determine the variance between IAP values using a range of volume infusions between 10 and 60 mL. Eighteen adult, surgical intensive care unit (SICU) patients who were undergoing IAP measurement for IAH or clinically indicated monitoring were enrolled in a prospective, nontreatment study. Intra-abdominal pressure measurements were obtained with stepwise increases of injectate volume from 10 to 60 mL (in 10 mL increments). Bland-Altman analyses and receiver operating characteristic (ROC) curves were used for analysis. After analysis accounting for data correlation within patients, means and standard deviations were generated for differences between 50 mL and 10, 20, 30, 40, and 60 mL bladder infusion volumes. Bland-Altman analyses showed good agreement between measurements and no significant difference in variance (mean < or =1.35 mm Hg) between volume comparisons. The ROC curve generated for each test volume using a diagnostic pressure value for IAH (!12 mm Hg) showed that a value between 11 and 12 mm Hg gave the best combination of sensitivity and specificity for all test volumes. In SICU patients, with a clinical indication for IAP monitoring, bladder infusion volumes between 10 mL and 60 mL provide consistent IAP measurements.

Reproducibility of bladder pressure measurements in critically ill patients.

OBJECTIVE: Intra-abdominal hypertension is an independent cause of multiorgan failure and directly effects other physiological measurements, making it an important factor in the management of critically ill patients, but no clinical studies have investigated the reproducibility of intra-abdominal pressure (IAP) measurement to ensure diagnostic accuracy. This study evaluated the intraobserver and interobserver variability of bladder pressure measurements. DESIGN AND SETTING: Prospective, observational study in a university-based adult surgical intensive care unit. PATIENTS: Critically ill patients undergoing intra-abdominal pressure readings, measured by nursing staff. MEASUREMENTS AND RESULTS: The study compared patient IAP measurements obtained by the same nurse (intraobserver variation) and between two different nurses (interobserver variation) in critical care patients with clinical indications for IAP monitoring. Data related to the nursing technique and performance were observed and collected for each IAP measurement obtained. Good correlation of bladder pressure measurements between the same and different individuals was found. Intraobserver and interobserver Pearson's correlations for measured IAP were 0.934 and 0.950, respectively. A unit protocol for IAP measurement standardization was modified based on observational data collected. CONCLUSIONS: Intra-abdominal pressure can be accurately and reliably measured in critically ill patients by utilizing a standardized measurement device combined with a standardized clinical protocol.

Survey of intensive care physicians on the recognition and management of intra-abdominal hypertension and abdominal compartment syndrome.

OBJECTIVE: To assess current understanding and clinical management of intra-abdominal hypertension and abdominal compartment syndrome among critical care physicians. DESIGN: A ten-question, written survey. SETTING: University health sciences center. SUBJECTS: Physician members of the Society of Critical Care Medicine (SCCM). INTERVENTIONS: The survey was sent to 4,538 SCCM members with a response rate of 35.7% (1622). MEASUREMENTS AND MAIN RESULTS: Primary training, intensive care unit type, and methods for management of abdominal compartment syndrome were assessed. Surgically trained intensivists managed the highest number of abdominal compartment syndrome cases (47% managed 4-10 cases, 16% managed >10 cases). No cases were seen by 25% of medically trained and pediatric trained intensivists. Respondents agreed that bladder pressures and clinical variables were needed to diagnose abdominal compartment syndrome (70%) vs. bladder pressure (7%) or clinical variables (20%) alone. Two percent of surgical intensivists were unaware of a bladder pressure measurement procedure compared with 24% (p < .0001) of pediatric and 23% (p < .0001) of medical intensivists. Forty-two percent of respondents believed bladder pressures of 20-27 mm Hg may cause physiologic compromise. However, 25-27% of pediatric, medicine, or anesthesia trained intensivists believed that compromise occurs between 12 and 19 mm Hg compared with 18% of surgeons. No respondent believed that physiologic compromise occurred at <8 mm Hg. Thirty-eight percent of pediatric intensivists believed that physiologic compromise was patient dependent vs. 7-17% from other specialties (p < .0001; all comparisons). In managing intra-abdominal hypertension, 33% of pediatric intensivists and 19.6% of medical intensivists would never use decompression laparotomy to treat abdominal compartment syndrome compared with 3.6% of intensivists with surgical training (p < .0001; both comparisons). CONCLUSIONS: Significant variation across medical training exists in the management of intra-abdominal hypertension and abdominal compartment syndrome. A significant percentage of intensivists may be unaware of current approaches to abdominal compartment syndrome management including monitoring bladder pressures and decompression laparotomy. Future research and education are necessary to establish clear diagnostic criteria and standards for treatment of this relatively common life-threatening disease process.