Intra-abdominal hypertension in patients with severe acute pancreatitis

Critical Care Vol9No4 Intra-abdominal hypertension in patients with severe acute pancreatitis Jan J De Waele1, Eric Hoste1, Stijn I Blot2, Johan Decruyenaere3 and Francis Colardyn4 Corresponding author: Jan J De Waele 0 Professor and Head, Intensive care unit, Ghent University Hospital , Gent , Belgium 1 Professor, Intensive care unit, Ghent University Hospital , Gent , Belgium 2 Intensivist, Intensive care unit, Ghent University Hospital , Gent , Belgium 3 Professor and Chief Executive Officer, Ghent University Hospital , Gent , Belgium Introduction Abdominal compartment syndrome has been described in patients with severe acute pancreatitis, but its clinical impact remains unclear. We therefore studied patient factors associated with the development of intra-abdominal hypertension (IAH), the incidence of organ failure associated with IAH, and the effect on outcome in patients with severe acute pancreatitis (SAP). - Methods We studied all patients admitted to the intensive care unit (ICU) because of SAP in a 4 year period. The incidence of IAH (defined as intra-abdominal pressure 15 mmHg) was recorded. The occurrence of organ dysfunction during ICU stay was recorded, as was the length of stay in the ICU and outcome. Results The analysis included 44 patients, and IAP measurements were obtained from 27 patients. IAH was found in 21 patients (78%). The maximum IAP in these patients averaged 27 mmHg. APACHE II and Ranson scores on admission were higher in patients who developed IAH. The incidence of organ dysfunction was high in patients with IAH: respiratory failure 95%, cardiovascular failure 91%, and renal failure 86%. Mortality in the patients with IAH was not significantly higher compared to patients without IAH (38% versus 16%, p = 0.63), but patients with IAH stayed significantly longer in the ICU and in the hospital. Four patients underwent abdominal decompression because of abdominal compartment syndrome, three of whom died in the early postoperative course. Conclusion IAH is a frequent finding in patients admitted to the ICU because of SAP, and is associated with a high occurrence rate of organ dysfunction. Mortality is high in patients with IAH, and because the direct causal relationship between IAH and organ dysfunction is not proven in patients with SAP, surgical decompression should not routinely be performed. Introduction Despite recent advances in the management of patients, such as early enteral nutrition and withholding surgery until proven infection of pancreatic necrosis, severe acute pancreatitis (SAP) remains a disease with an unpredictable clinical course and significant morbidity and mortality [1]. Infection still remains the most feared complication, but also the presence of organ dysfunction is increasingly recognized as an important risk factor for mortality in patients with severe disease [24]. Intra-abdominal hypertension (IAH) has been recognized as a cause of organ dysfunction in critically ill patients, with respiratory and renal dysfunction often most prominent [5]. This syndrome, referred to as the abdominal compartment syndrome, has most extensively been described in patients who underwent emergency abdominal surgery or after abdominal trauma, but also in patients with non-abdominal diseases such as burns [6] and massive fluid resuscitation [7]. Some recent studies [8,9] suggest that IAH is a frequent finding in SAP patients. The clinical relevance of this remains unclear, although Pupelis et al. [9] found a relation between elevated intra-abdominal pressure (IAP; above 25 mmHg) and persistent subsequent organ dysfunction. Tao et al. [10] described a high incidence of IAH in patients with early SAP, APACHE = Acute Physiology And Chronic Health Evaluation; IAH = intra-abdominal hypertension; IAP = intra-abdominal pressure; ICU = intensive care unit; SAP = severe acute pancreatitis. but lack of a definition of IAH and methodological issues make interpretation of these data difficult [10]. The levels at which elevated IAP can cause organ dysfunction are lower than in the study by Pupelis et al. Values of as low as 15 mmHg may result in clinically significant organ damage [11-13], but clinical significance of this lower threshold in patients with SAP remains to be determined. The aim of this analysis was to study patient factors associated with the development of IAH. Furthermore, we studied the incidence of organ failure in patients with SAP and IAH, and the association of the presence of IAH and outcome. Materials and methods Patients We studied all patients admitted because of SAP to the intensive care unit (ICU) of the Ghent University Hospital (Gent, Belgium) between January 2000 and March 2004. SAP was defined according to the criteria described by the International Symposium on Acute Pancreatitis [14]. Patients names were retrieved from the hospital registry using ICD code 577.0 (acute pancreatitis), and files were reviewed retrospectively. Patients who were referred from other hospitals later than 7 days after the start of SAP were excluded. The study was approved by the local ethical committee. Preoperative data collected included age, gender, etiology of SAP, C-reactive protein level, Ranson score and Acute Physiology And Chronic Health Evaluation (APACHE) II score [15] on admission and C-reactive protein at 48 h after admission. Data acquisition IAP values were measured every 8 h when IAP was below 15 mmHg, and every 4 h when above 15 mmHg, and were retrieved from the patients file. IAP was measured using the transvesical route, as described by Cheatham et al. [16], after instillation of 50 ml of saline in the bladder. IAP measurements were obtained from patients when multiple intra-abdominal fluid collections were present on CT scan on admission, or when there was the clinical suspicion of IAH. These clinical indications included oliguria, hypoxia, abdominal distension, and severe abdominal pain. The incidence of IAH (defined as IAP 15 mmHg) was recorded, as was the maximal IAP value obtained during ICU stay, and the duration of IAP levels 15 mmHg. The occurrence rate of organ dysfunction during ICU stay was recorded and defined as: cardiovascular, hypotension requiring vasoactive medication (epinephrine, norepinephrine, dobutamine at any dose, or dopamine at doses above 2 mcg/kg/ min); renal, serum creatinine above 2.0 mg/dl; pulmonary, the need for mechanical ventilation or PaO2/FiO2 ratio < 300. Mortality was defined as in-hospital mortality. Interventions to alleviate IAH were recorded, as were complications of these interventions. Decompressive laparotomy was considered when rapidly deteriorating, therapy resistant multiple organ dysfunction was present in the first days after admission, and decided on a patient to patient basis. Statistical analysis Statistical analysis was performed using SPSS for Windows 11.0.1 (SPSS, Chicago, IL, USA). Continuous variables were compared using the Mann Whitney U-t (...truncated)