Intra-abdominal hypertension in the intensive care unit

Abstract

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade. The wide variety of definitions leads to confusion and difficulty in daily activity. Goal of study: Elucidate the leading causes of IAH in intensive care unit and the systemic effects of elevated intraabdominal pressure. Materials and methods: The study included 22 patients who had monitored intraabdominal pressure, the total number of measuring being 33. The average age of patients was 53,9. The patient’s severity state was quantified by APACHE II score, the average being 15,9. The measurement of intra-abdominal pressure (IAP) was performed by indirect method - urinary bladder pressure measurement. Results: The leading causes of IAH were: intraperitoneal surgical pathology in 68% (n=15), retroperitoneal pathology in 27%(n=6) and one case of ventral hernia cure complicated by IAH. The average of IAP was 15,58 mmHg, the highest value was recorded at the patients with retroperitoneal pathology. Carrying on analysis of systemic effects of IAH was marked tachypnea at the patients whose IAP exceeded the value of 15mmHg. Signs of pulmonary shunt was found in 84,85% cases, the ratio of Pa02/PA02 being 0,47. Comparing LAP values at the patients who had signs of pulmonary shunt and competitor group was noted a negligible difference. At the patients with IAH was noted a slight tendency to tachycardia, the average heart rate being 93.64±15.91 per min. False high values of central venous pressure (CVP) have been recorded at the patients whose IAP exceeded the value of 20mmHg. The average level of serum creatinine in the single group was 111,44 pmol/dl. Higher serum creatinine values were recorded at the patients with increased values of IAP as impairment of kidney function. Discussion and conclusions: Abdominal hypertension is a more common phenomenon in intensive care unit than seems to be at first sight. Causes leading to elevated intraabdominal pressure are diverse, but unified according to certain principles can be separated into 3 anatomical large groups: intraperitoneal, retroperitoneal pathology and those related to abdominal wall. Elevated intraabdominal pressure has systemic reflexion. Prevalence of pulmonary shunt at the patients with IAP<15 mm Hg versus those with IAP>15mmHg can be explained by other origins than intraabdominal hypertension when IAP value doesn’t exceed 20mmHg. Hemodynamic effects are manifested by high false CVP value, which is a surrogate of preload and reflects indirect volemic state. Intra-abdominal pressure less than 20mmHg had minimal systemic effects while IAP exceeding 20mmHg is responsible for the compromising of at least one organ system.