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Still a lot to learn about abdominal compartment syndrome

At CX 2014, a mini symposium on abdominal compartment syndrome shed light on how little is known about the condition. It became apparent that the syndrome still has not been clearly defined, many of its triggering factors have yet to be recognised, and its management is limited to surgical decompression. Therefore, preventing both intra-abdominal hypertension and preventing intra-abdominal aortic hypertension from developing into abdominal aortic compartment syndrome is key.

Jan de Waele (Ghent, Belgium) stated that abdominal compartment syndrome has gone from being a syndrome that many vascular surgeons thought is “imaginary” to one that was now “being taken seriously.” He added that, according to the definitions of the World Society of the Abdominal Compartment Syndrome (WASCS), the syndrome was now defined as sustained intra-abdominal pressure of 20mmHg and it is associated with new organ dysfunction. “It can be a combination of haemodynamic problems, respiratory dysfunction, metabolic acidosis, and acute kidney dysfunction,” de Waele commented. However, he reported that “organ dysfunction sets in if you just look for it” at the threshold for intra-abdominal hypertension (a sustained pressure of 12mmHg or more). Therefore, he said it “made sense” to take steps to prevent both intra-abdominal hypertension and abdominal compartment syndrome. De Waele added: “We know the patients who are at risk, so we can really target intervention and we a have an indicator available—the intra-abdominal pressure.”

Anders Wanhainen (Uppsala, Sweden) explained that the WASCS had identified that risk factors for intra-abdominal hypertension and abdominal compartment syndrome included diminished abdominal wall compliance, increased intra-abdominal contents, capillary leak/fluid resuscitation, and increased intra-luminal contents. He noted that many of these risk factors were “relevant for vascular surgeons, particularly those managing patients with ruptured abdominal aortic aneurysms.” For example, Wanhainen explained, ruptured aortic aneurysms are associated with major trauma, intra-abdominal fluid collection, acidosis, hypothermia, polytransfusion, and shock or hypotension. He added: “Repair of a ruptured abdominal aortic aneurysm is definitely a high-risk procedure for the development of abdominal compartment syndrome.” According to Wanhainen, a study found that about 50% of patients undergoing open repair develop intra-abdominal hypertension and about 20% develop abdominal compartment syndrome. He added that these figures were, respectively, about 20% and 10% in patients undergoing endovascular aortic aneurysm repair (EVAR) but commented: “The observed lower risk after EVAR for a ruptured abdominal aortic aneurysm will probably change when more patients in shock are treated with EVAR.”

Wanhainen stated that because of the risk of intra-abdominal hypertension and abdominal compartment syndrome, intra-abdominal pressure “can and should be measured, preferably at the bedside in the intensive care unit” in patients undergoing emergency surgery or EVAR for a ruptured abdominal aortic aneurysm. He added that it was “completely possible” to eliminate the problem of abdominal compartment syndrome by taking adequate preventative measures—these measured included early bleeding control (which he called “crucial”), judicious fluid resuscitation, and prophylactic open abdomen management in selected patients. He added that preoperative and intraoperative factors could help to determine which patients should be selected for open abdomen management.

Martin Björck (Uppsala, Sweden) also stated that prevention was important in the management of intra-abdominal hypertension/abdominal compartment syndrome. In the context of EVAR/open repair, he said that prevention “started at the operating table.” He noted that this involved “a massive transfusion protocol and avoiding crystalloids,” agreeing with de Waele that it was “crucial” to monitor intra-abdominal pressure in all patients after aortic aneurysm repair in the postoperative period.

Björck noted: “We prevent abdominal compartment syndrome with aggressive medical management [in patients with intra-abdominal hypertension] but sometimes abdominal decompression is necessary.” He added, in terms of medical management, early pain relief could be “remarkably effective” and neuromuscular blockade, if the patient needs mechanical ventilation, was also very effective.

Björck reported that the recently updated 2013 WASCS guidelines were able to give strong recommendations for the management of abdominal compartment syndrome. He said that the guidelines recommend decompression laparotomy if abdominal compartment syndrome was present, protocolled effort should be made to obtain an early abdominal closure as “severe complications” can occur if open abdomen therapy is prolonged, and strategies using negative pressure wound therapy should be used. Björck agreed with de Waele that open abdomen treatment as a preventative treatment was an option as it “made sense” not to close a tense abdomen [in patients undergoing open repair] even though there are no data to support this approach.

However, he added if delegates used the preventative open abdomen therapy, they should close the abdomen “quickly”.

De Waele also spoke about the management of intra-abdominal hypertension/abdominal compartment syndrome, focusing on critical care. He said that the introduction of medical management options to decrease intra-abdominal pressure had “significantly changed the management of patients with intra-abdominal hypertension” and expanded on the WASCS recommendations—“The WASCS medical management algorithm identified five targets for medical interventions such as nasogastric decompression, neuromuscular blocking agents and percutaneous drainage among others. It is estimated that medical management can avoid surgery in a large proportion of patients with impending abdominal compartment syndrome.” However, de Waele said that surgical decompression remained an important element in the armamentarium and “may still be required” in some patients with therapy resistant abdominal compartment syndrome and significant organ derangement.” Concluding, he said that the management of abdominal compartment syndrome had now become the management of intra-abdominal hypertension as monitoring intra-aortic pressure was the “first and essential step” and prevention should be used where possible.

Charing Cross chairman Roger Greenhalgh (London, UK) told CX Daily News: “If I were a young physician, looking for an area to elucidate, I would choose abdominal compartment syndrome.”

 

2015-07-11T02:23:23+00:00