Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade. In the absence of consensus definitions and treatment guidelines the diagnosis and management of IAH and ACS remains variable from institution to institution. An international consensus group of multidisciplinary critical care specialists convened at the second World Congress on Abdominal Compartment Syndrome to develop practice guidelines for the diagnosis, management, and prevention of IAH and ACS. Prior to the conference the authors developed a blueprint for consensus definitions and treatment guidelines which were refined both during and after the conference. The present article is the second installment of the final report from the 2004 International ACS Consensus Definitions Conference and is endorsed by the World Society of the Abdominal Compartment Syndrome. The prevalence and etiological factors for IAH and ACS are reviewed. Evidence-based medicine treatment guidelines are presented to facilitate the diagnosis and management of IAH and ACS. Recommendations to guide future studies are proposed. These definitions, guidelines, and recommendations, based upon current best evidence and expert opinion are proposed to assist clinicians in the management of IAH and ACS as well as serve as a reference for future clinical and basic science research.

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Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. II. Recommendations.

ObjectiveIntra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade. The variety of definitions proposed has led to confusion and difficulty in comparing one study to another.DesignAn international consensus group of critical care specialists convened at the second World Congress on Abdominal Compartment Syndrome to standardize definitions for IAH and ACS based upon the current understanding of the pathophysiology surrounding these two syndromes.MethodsPrior to the conference the authors developed a blueprint for the various definitions, which was further refined both during and after the conference. The present article serves as the final report of the 2004 International ACS Consensus Definitions Conference and is endorsed by the World Society of Abdominal Compartment Syndrome (WSACS).ResultsIAH is redefined as an intra-abdominal pressure (IAP) at or above 12 mmHg. ACS is redefined as an IAP above 20 mmHg with evidence of organ dysfunction/failure. ACS is further classified as either primary, secondary, or recurrent based upon the duration and cause of the IAH-induced organ failure. Standards for IAP monitoring are set forth to facilitate accuracy of IAP measurements from patient to patient.ConclusionsState-of-the-art definitions for IAH and ACS are proposed based upon current medical evidence as well as expert opinion. The WSACS recommends that these definitions be used for future clinical and basic science research. Specific guidelines and recommendations for clinical management of patients with IAH/ACS are published in a separate review.

Results from the international conference of experts on intra-abdominal hypertension and abdominal compartment syndrome

Keeping pace with the stream of new data and evolving evidence on which guideline recommendations are based is an ongoing challenge to timely development of clinical practice guidelines. In an effort to respond promptly to new evidence, the American College of Cardiology Foundation/American Heart Association (ACCF/AHA) Task Force on Practice Guidelines (Task Force) has created a “focused update” process to revise the existing guideline recommendations that are affected by the evolving data or opinion. New evidence is reviewed in an ongoing fashion to more efficiently respond to important science and treatment trends that could have a major impact on patient outcomes and quality of care. Evidence is reviewed at least twice a year, and updates are initiated on an as-needed basis and completed as quickly as possible while maintaining the rigorous methodology that the ACCF and AHA have developed during their partnership of >20 years.

These updated guideline recommendations reflect a consensus of expert opinion after a thorough review primarily of late-breaking clinical trials identified through a broad-based vetting process as being important to the relevant patient population, as well …

2011 ACCF/AHA Focused Update of the Guideline for the Management of Patients With Peripheral Artery Disease (Updating the 2005 Guideline) A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines

Objective: Intraabdominal hypertension is associated with significant morbidity and mortality in surgical and trauma patients. The aim of this study was to assess, in a mixed population of critically ill patients, whether intraabdominal pressure at admission was an independent predictor for mortality and to evaluate the effects of intraabdominal hypertension on organ functions. Design: Multiple-center, prospective epidemiologic study. Setting: Fourteen intensive care units in six countries. Patients: A total of 265 consecutive patients admitted for >24 hrs during the 4-wk study period. Interventions: None. Measurements and Main Results: Intraabdominal pressure was measured twice daily via the bladder. Data recorded on admission were the patient demographics with Simplified Acute Physiology Score II, Acute Physiology and Chronic Health Evaluation II score, and type of admission; during intensive care stay, Sepsis-Related Organ Failure Assessment score and intraabdominal pressure were measured daily together with fluid balance. Nonsurvivors had a significantly higher mean intraabdominal pressure on admission than survivors: 11.4 4.8 vs. 9.5 4.8 mm Hg. Independent predictors for mortality were age (odds ratio, 1.04; 95% confidence interval, 1.01‐1.06; p .003), Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.1; 95% confidence interval, 1.05‐1.15; p < .0001), type of intensive care unit admission (odds ratio, 2.5 medical vs. surgical; 95% confidence interval, 1.24‐5.16; p .01), and the presence of liver dysfunction (odds ratio, 2.5; 95% confidence interval, 1.06‐5.8; p .04). The occurrence of intraabdominal hypertension during the intensive care unit stay was also an independent predictor of mortality (relative risk, 1.85; 95% confidence interval, 1.12‐3.06; p .01). Patients with intraabdominal hypertension at admission had significantly higher Sepsis-Related Organ Failure Assessment scores during the intensive care unit stay than patients without intraabdominal hypertension. Conclusions: Intraabdominal hypertension on admission was associated with severe organ dysfunction during the intensive care unit stay. The mean intraabdominal pressure on admission was not an independent risk factor for mortality; however, the occurrence of intraabdominal hypertension during the intensive care unit stay was an independent outcome predictor. (Crit Care Med 2005; 33:315‐322)

Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: a multiple-center epidemiological study.

Although intra-abdominal hypertension (IAH) can cause dysfunction of several organs and raise mortality, little information is available on the incidence and risk factors for IAH in critically ill patients This study assessed the prevalence of IAH and its risk factors in a mixed population of intensive care patients A multicentre, prospective 1-day point-prevalence epidemiological study conducted in 13 ICUs of six countries None Ninety-seven patients admitted for more than 24 h to one of the ICUs during the 1-day study period Intra-abdominal pressure (IAP) was measured four times (every 6 h) by the bladder pressure method Data included the demographics, medical or surgical type of admission, SOFA score, etiological factors such as abdominal surgery, haemoperitoneum, abdominal infection, massive fluid resuscitation, and ileus and predisposing conditions such as hypothermia, acidosis, polytransfusion, coagulopathy, sepsis, liver dysfunction, pneumonia and bacteraemia We enrolled 97 patients, mean age 64±15 years, 57 (59%) medical and 40 (41%) surgical admission, SOFA score of 65±40 Mean IAP was 98±47 mmHg The prevalence of IAH (defined as IAP 12 mmHg or more) was 505 and 82% had abdominal compartment syndrome (defined as IAP 20 mmHg or more) The only risk factor significantly associated with IAH was the body mass index, while massive fluid resuscitation, renal and coagulation impairment were at limit of significance Although we found a quite high prevalence of IAH, no risk factors were reliably associated with IAH; consequently, to get valid information about IAH, IAP needs to be measured

Prevalence of intra-abdominal hypertension in critically ill patients: a multicentre epidemiological study.

Objective: To define the incidence, prophylaxis, and treatment of intra-abdominal hypertension (IAH) and its relevance to gut mucosal pH (pHi), multiorgan dysfunction syndrome, and the abdominal compartment syndrome (ACS). Methods: Seventy patients in the SICU at a Level I trauma center (1992-1996) with life threatening penetrating abdominal trauma had intra-abdominal pressure estimated by bladder pressure. pHi was measured by gastric tonometry every 4 to 6 hours. IAH (intra-abdominal pressure> 25 cm of H 2 O) was treated by bedside or operating room laparotomy. Results: Injury severity was comparable between patients who had mesh closure as prophylaxis for IAH (n = 45) and those who had fascial suture (n = 25). IAH was seen in 10 (22.2%) in the mesh group versus 13 (52%) in the fascial suture group (p = 0.012) for an overall incidence of 32.9%. Forty-two patients had pHi monitoring, and 11 of them had IAH. Of the 11patients, eight patients (72.7%) had acidotic pHi (7.10± 0.2) with IAH without exhibiting the classic signs of ACS. The pHi improved after abdominal decompression in six and none developed ACS. Only two patients with IAH and low pHi went on to develop ACS, despite abdominal decompression. Multiorgan dysfunction syndrome points and death were less in patients without IAH than those with IAH and in patients who had mesh closure. Conclusions: IAH is frequent after major abdominal trauma. It may cause gut mucosal acidosis at lower bladder pressures, long before the onset of clinical ACS. Uncorrected, it may lead to splanchnic hypoperfusion, ACS, distant organ failure, and death. Prophylactic mesh closure of the abdomen may facilitate the prevention and bedside treatment of IAH and reduce these complications.

Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: prophylaxis, incidence, and clinical relevance to gastric mucosal pH and abdominal compartment syndrome.

One hundred hemodynamically stable patients with penetrating abdominal trauma (65, stab wounds, 35, gunshot wounds) were evaluated with laparoscopy Sixty percent of the patients had wounds in the thoracoabdominal area or the upper abdominal quadrants and 25% had injuries located in the lower abdomen and flanks Fifteen percent had epigastric wounds Twenty-two stabs and 21 gunshots had not penetrated the peritoneum (negative laparoscopic results) Fifty-seven patients had peritoneal penetration and were noted to have hemoperitoneum only (n = 14), hemoperitoneum and solid organ injuries (n = 23), diaphragmatic lacerations (n = 17), and hollow viscus injuries (n = 2) on laparoscopic examination Three of the 57 patients, one with omental herniation only and two with low grade nonbleeding lacerations of the liver, were managed uneventfully without laparotomy The remaining 54 patients underwent laparotomy with confirmation of the laparoscopic findings Seven patients (three with stab wounds and four with gunshots) had additional GI tract injuries seen at laparotomy The diagnostic accuracy of laparoscopy was excellent for hemoperitoneum, solid organ injuries, diaphragmatic lacerations, and retroperitoneal hematomas For GI injuries, laparoscopy was found to have a 100% specificity but only a 18% sensitivity The majority of these discordant findings occurred in epigastric SWs and flank and lower quadrant GSWs, all in patients with undetected hollow viscus injuries The major role of laparoscopy in penetrating abdominal trauma is in avoiding unnecessary laparotomy in tangential SWs and GSWs It is excellent for evaluating the diaphragm in thoracoabdominal wounds Caution is urged in excluding hollow viscus injuries based on laparoscopy

A critical evaluation of laparoscopy in penetrating abdominal trauma.

BACKGROUND Gastric tonometry, as a method of organ-specific monitoring of the status of the splanchnic circulation, has demonstrated prognostic and therapeutic implications in critically ill patients. The experience with this method in patients with trauma has been limited. STUDY DESIGN Fifty-seven patients were prospectively randomized into two groups: group 1, n = 30, normalization and maintenance of gastric mucosal pH (pHi) at or above 7.3 and group 2, n = 27, maintenance of oxygen delivery index of 600 or an oxygen consumption index of greater than 150. The groups had statistically similar injury severity scores, lactate levels, and base deficits. RESULTS Of the 44 patients with pHi greater than 7.3 at 24 hours, three (6.8 percent) died of multiple organ dysfunction syndrome as compared with seven (53.9 percent) of 13 in whom pHi was not optimized, p = 0.006. Optimization times for oxygen delivery index, oxygen consumption index, lactate levels, and base excess were similar between survivors and nonsurvivors. The time for pHi optimization was significantly longer in nonsurvivors. Multiple organ dysfunction syndrome points were significantly higher in patients who did not have pHi optimized within 24 hours (6.08 compared with 2.5, p = 0.03). Optimization time for pHi was predictive of mortality on multiple regression. Persistently low pHi was frequently associated with systemic or intra-abdominal complications. It was the first finding in all the nonsurvivors at least 48 to 72 hours before death. CONCLUSIONS Gastric mucosal pH may be an important marker to assess the adequacy of resuscitation. Monitoring of pHi may provide early warning for systemic complications in the postresuscitation period.

A prospective randomized study of end points of resuscitation after major trauma: global oxygen transport indices versus organ-specific gastric mucosal pH.

Objective : To compare gastric mucosal pH (pHi) and global oxygen variables [Oxygen Delivery Index (DO 2 I) and Oxygen Consumption Index (VO 2 I)] as indicators of adequacy of resuscitation after major trauma. Methods : Twenty-seven patients were prospectively randomized into two groups : group 1 (n = 11), normalization and maintenance of pHi at or above 7.30 ; and group 2 (n = 16), maintaining a DO 2 I of 600 and a VO 2 I of >150. The groups had statistically similar injury severity scores, lactate, and base deficit. Results : The goals of therapy were achieved within 24 hours of admission in 10 of the 11 patients in group 1 and in 15 of the 16 patients in group 2. One patient (9.1%) in group 1 died. This patient had transient stabilization of pHi to 7.3 and subsequently had persistent mucosal acidosis. Of the 10 patients with pHi > 7.3 at 24 hours, 9 survived. In group 2, 5 (31.3%) died. Four of the 5 nonsurvivors had achieved DO 2 I and VO 2 I goals, but had pHi < 7.3 at 24 hours. A comparison of time taken for optimization of DO 2 I, VO 2 I, lactate, base excess, and pHi showed pHi and lactate as the variables different in survivors and nonsurvivors. Six of the 8 patients who developed multiple organ dysfunction syndrome had pHi < 7.3 at 24 hours. Persistently low pHi was the first sign of bacteremia (3 patients), small bowel gangrene or pregangrene (2 patients), intestinal anastomotic leak (2 patients), intra-abdominal hypertension (4 patients), and intra-abdominal abscess (5 patients). It was the first finding in all the nonsurvivors at least 72 hours before death. Conclusions : pHi may be an important marker to assess the adequacy of resuscitation. pHi monitoring may provide early warning for systemic complications in the postresuscitation period.

Gastric mucosal pH and oxygen delivery and oxygen consumption indices in the assessment of adequacy of resuscitation after trauma: a prospective, randomized study.

Background: Intra-abdominal hypertension has been associated with pulmonary and cardiac dysfunctions. We have noted in the clinical scenario of hemorrhagic shock and resuscitation that avoidance of even moderate levels of increased intra-abdominal pressure, using prophylactic decompression, improves outcomes when compared with patients who were decompressed when intra-abdominal pressures went over 20 cm H 2 O. We hypothesized that prior hemorrhage and resuscitation exacerbates the cardiopulmonary dysfunction associated with intra-abdominal hypertension. Methods: Ten anesthetized pigs underwent placement of arterial and pulmonary artery catheters and a Silastic intra-abdominal catheter for measuring and manipulating intra-abdominal pressure. Group 1 animals (n = 5) were subjected to increasing intra-abdominal pressures at 10 mm Hg increments up to a level of 40 mm Hg. Group 2 animals (n = 5) were exposed to a severe hemorrhage and resuscitation before the increasing intra-abdominal pressure protocol. Results: Compared with baseline, hemorrhage and resuscitation caused a significant deterioration in cardiac output at intraabdominal pressures of 10 mm Hg and above. Oxygenation was reduced at 30 and 40 mm Hg. These changes were not seen in group 1 animals. A significant difference was found between groups 1 and 2 in VT, Paco 2 , and Paco 2 /Fio 2 ratio at an intra-abdominal pressure of 20 mm Hg. This difference was not seen at lower or higher pressures. Conclusions: Prior hemorrhage and resuscitation caused an earlier decline in cardiopulmonary function in the setting of increased intra-abdominal pressure. These data suggest that, when interpreting intra-abdominal pressures, the clinical scenario must be considered. Prior hemorrhage and resuscitation produce the adverse consequences of intra-abdominal hypertension at lower pressures than when intra-abdominal hypertension is the only insult.

R. R. Ivatury

Papers

Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: prophylaxis, incidence, and clinical relevance to gastric mucosal pH and abdominal compartment syndrome.

A critical evaluation of laparoscopy in penetrating abdominal trauma.

A prospective randomized study of end points of resuscitation after major trauma: global oxygen transport indices versus organ-specific gastric mucosal pH.

Gastric mucosal pH and oxygen delivery and oxygen consumption indices in the assessment of adequacy of resuscitation after trauma: a prospective, randomized study.

Hemorrhage lowers the threshold for intra-abdominal hypertension-induced pulmonary dysfunction.