Validation and experience with a simple continuous intra-abdominal pressure measurement technique in a multidisciplinary medical/surgical critical care unit

Reliability of intra-abdominal pressure measurements using the modified Kron technique

OBJECTIVES

Assessment of intra-abdominal pressure (IAP) and the likelihood of abdominal compartment syndrome using valid and reliable measures is an important tool in the assessment of critically ill patients. The current method of relying on a single IAP per measurement period to determine patient clinical status raises the question: is a single intermittent IAP measurement an accurate indicator of clinical status or should more than one measurement be taken per measurement period?

METHODS

This study sought to assess the reliability of IAP measurements. Measurements were taken using the modified Kron technique. A total of two transvesical intra-abdominal pressure measurements were undertaken per patient using a standardized protocol. Recordings were taken at intervals of 5 minutes.

RESULTS

The majority of participants (58%) were surgical patients. Thirty-two were males and the mean age was 58 years (SD: 16·7 years). The concordance correlation coefficient between the two measurements was 0·95. Both the scatter and Bland-Altman plots demonstrate that the comparisons of two measurements are highly reproducible.

CONCLUSION

The findings of this study suggest that conducting two IAP measurements on single patient produce comparable results; therefore, there appears to be no advantage in doing two IAP measurements on a single patient. The measurement of an IAP requires the implementation of a standardized protocol and competent and credentialed assessors trained in the procedure.

Measurement of intra-abdominal pressure in dogs and cats

OBJECTIVE

To review and summarize the human and veterinary literature on intra-abdominal pressure measurement techniques.

DATA SOURCES

Human and veterinary clinical studies, research articles, reviews, and textbooks with no date restrictions with a focus on techniques for intra-abdominal pressure (IAP) measurement and their limitations.

HUMAN DATA SYNTHESIS

Human literature has established the intravesicular method as the gold standard for indirect measurement of IAP. However, current research has explored the intragastric method as a valid alternative. Recently, debate has focused on the shortcomings of the various measurement methods.

VETERINARY DATA SYNTHESIS

Early human literature using dogs as models contributed to the original data for IAP measurements in small animals. Since that time, a number of clinical studies and 1 case report have contributed to that original information. A reference interval for IAP measured by the intravesicular method has recently been determined in healthy cats.

CONCLUSIONS

Further studies investigating IAP in critically ill veterinary patients are required to establish the optimal technique for this measurement in veterinary medicine.

Intra-abdominal Hypertension and Abdominal Compartment Syndrome

Intra-abdominal hypertension has a prevalence of at least 50% in the critically ill population and has been identified as an independent risk factor for death. Yet, many of the members of the critical care team do not assess for intra-abdominal hypertension and are unaware of the consequences of untreated intra-abdominal hypertension. These consequences can be abdominal compartment syndrome, multisystem organ failure, and death. This article provides an overview of the pathophysiology of intra-abdominal hypertension and abdominal compartment syndrome. In addition, the evidence-based definitions, guidelines, and recommendations of the World Society of the Abdominal Compartment Syndrome are presented.

Bladder pressure measurements are an independent predictor of urinary tract infection in trauma patients

PURPOSE

To determine the risk factors for urinary tract infections (UTIs) specific to trauma patients in order to assist in the development of infection control protocols.

METHODS

Data were collected prospectively from January 2003 until December 2005 by an epidemiology nurse and combined with registry data from our Level 1 trauma center. The trauma patients admitted to the Surgery and Trauma Intensive Care Unit (STICU)(n = 938) who did and did not have UTIs were compared for demographics, Injury Severity Score (ISS), and epidemiologic data, including use of Foley catheters and bladder pressure measurements (BPMs). An open system was used for the measurements in which the catheter was disconnected from the bag to instill 50 mL of saline into the bladder, and an 18-gauge needle was inserted into the catheter to measure the pressure.

RESULTS

A total of 50 patients had no Foley catheter or UTIs. Among the 836 patients with catheters but no BPMs, there were 36 UTIs (4.31%), whereas the 52 patients with catheters and BPMs had 12 UTIs (23.08%)(p < 0.0001). Patients with UTIs were more severely injured older females (mean age 40.1 ± 18.6 years with no UTI vs. 48.5 ± 20.8 with UTIs; p = 0.0083; percent female 26.4 no UTI vs. 45.8 UTI; p = 0.007; ISS 19.3 ± 11.3 no UTI vs. 26.2 ± 11.6; p < 0.0001). Using logistic regression, BPM was an independent predictor of UTI, with infection being seven times more likely in the patients having the measurements (odds ratio [OR] 6.99; 95% confidence-interval [CI] 3.087-15.827). Along with age (OR 1.039; CI 1.024-1.054) and ISS (OR 1.081; CI 1.056-1.106), having BPMs was an independent predictor of death (OR 2.475; CI 1.191-6.328).

CONCLUSION

This is the first study that demonstrates a greater risk of UTI with BPM using the open technique independent of patient gender or degree of injury. Given these findings and a previous trial demonstrating no difference in UTI rates with a closed circuit for BPM, our institution has incorporated a closed circuit technique into its infection control protocol.

Abdominal compartment syndrome in trauma resuscitation

PURPOSE OF REVIEW

Swelling is inexorably linked to shock and resuscitation in trauma. In many forms, swelling complicates and interacts with traumatic injury to raise pressures in the abdomen, resulting in intraabdominal hypertension, which may overtly manifest as abdominal compartment syndrome (ACS) driving multiple organ failure. Despite renewed clinical interest in posttraumatic intraabdominal pressure, there remains a chiasm between knowledge of the risks and clinical interventions to mitigate them. This review provides a concise overview of definitions, risk factors, diagnosis and management using an illustrative trauma case.

RECENT FINDINGS

Intraabdominal pressure commonly increases following trauma, wherein ACS may manifest earlier than generally appreciated and complicate other insults such as shock and hemorrhage. Contemporary resuscitation strategies may exacerbate intraabdominal hypertension, particularly massive crystalloid resuscitation. Although unproven, the recent transition to crystalloid restriction and high plasma resuscitation strategies may influence the prevalence of ACS. Nonetheless, aggressive intraabdominal pressure monitoring should be mandatory in the critically ill. Despite potential nonoperative options, decompressive laparotomy remains the only definitive but often morbid treatment.

SUMMARY

ACS results from many dysfunctions acting in concert with each other in self-propagating vicious cycles. Starting with greater awareness, it is imperative that the growing knowledge should be translated into clinical practice.

Comparison of a new device for the continuous intra-gastric measurement of intra-abdominal pressure (CiMon) with direct intra-peritoneal measurements in cirrhotic patients during paracentesis

OBJECTIVE

To evaluate a new commercially available system for the intra-gastric measurement of intra-abdominal pressure (IAP).

DESIGN AND SETTING

Prospective interventional trial in an intensive care unit of a university hospital.

PATIENTS

Ten patients with cirrhosis and tense ascites scheduled for paracentesis and instrumented with a ballon-tipped nasogastric tube.

INTERVENTION

Intermittent paracentesis with repeat paired measurements of IAP.

MEASUREMENTS AND RESULTS

Intra-abdominal pressure was measured directly through the paracentesis catheter using a scaled measurement gauge. Simultaneously, intra-gastric measurements were performed with the CiMon device (Pulsion Medical Systems, Munich, Germany), by means of a ballon-tipped nasogastric tube connected to a pressure transducer. The range of IAP was 6.5-28 mmHg for direct measurements and 3.7-16 mmHg for measurements obtained with the CiMon device. The regression equation according to Passing and Bablok for the two methods had an intercept of 0.054 (95% CI-1.475-1.669) and a slope of 0.674 (95% CI 0.538-0.813). The cusum test showed a significant deviation from linearity (P < 0.05). In the Bland-Altman test bias and limits of agreement were - 4.9 (+/-6.8) mmHg or, expressed as percentage of the average, -44% (+/-49%).

CONCLUSION

Intra-gastric measurements of IAP using the CiMon device were not reliable enough to be clinically useful in these ascitic patients.