Results from the International Conference of Experts on Intra-Abdominal Hypertension (IAH) and Abdominal Compartment Syndrome (ACS): Results from the International Conference of Experts on Intra-Abdominal Hypertension (IAH) and Abdominal Compartment Syndrome (ACS) RECOMMENDATIONS
Intensive Care Medicine 2007; 33(6): 951-962
INTRODUCTION TO THE RECOMMENDATIONS: INTRODUCTION TO THE RECOMMENDATIONS Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are causes of significant morbidity and mortality in the critically ill
Intra-abdominal pressure (IAP) measurements are essential to the diagnosis of both IAH and ACS
The World Society of the Abdominal Compartment Syndrome (WSACS) has created evidence-based medicine recommendations for the management of patients with IAH/ACS
GRADES OF EVIDENCE: GRADES OF EVIDENCE Evidence-based guidelines are now commonplace in medicine
The WSACS has adopted a modification of the approach developed by the international GRADE group
Recommendations are classified as either strong recommendations (Grade 1) or weak suggestions (Grade 2)
Quality of evidence is ranked as high (grade A), moderate (grade B), or low (grade C)
While difficult to perform given the acuity of IAH/ACS, these recommendations emphasize the need for rigorous clinical trials to be performed in the future
OVERVIEW: OVERVIEW Given the wide variety of patients that may develop IAH/ACS, no one management strategy can be uniformly applied to all patients
While surgical decompression is commonly considered the only treatment, non-operative medical management strategies play a vital role in the prevention and treatment of IAH-induced organ dysfunction and failure
Appropriate IAH/ACS management is based upon four principles:
Serial monitoring of IAP
Optimization of systemic perfusion and organ function
Institution of specific medical interventions to reduce IAP
Prompt surgical decompression for refractory IAH
RECOMMENDATIONS:RISK FACTORS & SURVEILLANCE FOR IAH/ACS: RECOMMENDATIONS: RISK FACTORS & SURVEILLANCE FOR IAH/ACS Patients should be screened for IAH / ACS risk factors upon ICU admission and in the presence of new or progressive organ failure (Grade 1B)
Independent risk factors for IAH / ACS include:
Large volume fluid resuscitation (> 3.5 L / 24 hrs)
Acidosis
Hypothermia
Coagulopathy / polytransfusion
Pulmonary, renal, hepatic dysfunction
Ileus
Abdominal surgery / primary fascial closure
RECOMMENDATIONS:IAP MEASUREMENT: RECOMMENDATIONS: IAP MEASUREMENT If two or more risk factors for IAH / ACS are present, a baseline IAP measurement should be obtained (Grade 1B)
If IAH is present, serial IAP measurements should be performed throughout the patient’s critical illness (Grade1C)
Physical examination is insensitive in detecting IAH
IAP monitoring is a cost-effective, safe, and accurate tool for identifying the presence of IAH and guiding resuscitative therapy for ACS
Serial IAP measurements are necessary to guide resuscitation of patients with IAH / ACS
RECOMMENDATIONS:IAP MEASUREMENT TECHNIQUE: RECOMMENDATIONS: IAP MEASUREMENT TECHNIQUE Studies should adopt the standardized IAP measurement method recommended by the consensus definitions OR provide sufficient detail of the technique utilized to allow accurate interpretation of the IAP data presented (Grade 2C)
IAP should be measured:
In mmHg (1 mmHg = 1.36 cm H2O)
In the supine position at end-expiration with the transducer zeroed at the mid-axillary line
Using an instillation volume of no greater than 25 mL (1 mL/kg for children up to 20 kg) for the bladder technique
30-60 seconds after instillation of priming fluid to allow bladder detrusor muscle relaxation
In the absence of active abdominal muscle contractions
Slide8: IAH ASSESSMENT ALGORITHM www.wsacs.org
RECOMMENDATIONS:ABDOMINAL PERFUSION PRESSURE: RECOMMENDATIONS: ABDOMINAL PERFUSION PRESSURE APP should be maintained above 50–60 mmHg in patients with IAH/ACS (Grade 1C)
The critical IAP that leads to organ failure varies by patient
A single threshold IAP cannot be applied to all patients
APP assesses not only the severity of IAP, but also the relative adequacy of abdominal blood flow
APP is superior to IAP, arterial pH, base deficit, and arterial lactate in predicting organ failure and patient outcome
Failure to maintain APP > 50-60 mmHg in patients with IAH predicts survival
RECOMMENDATIONS:SEDATION AND ANALGESIA: RECOMMENDATIONS: SEDATION AND ANALGESIA No recommendations can be made at this time
Pain, agitation, ventilator dyssynchrony, and accessory muscle use during breathing may all lead to increased abdominal muscle tone
This increased muscle activity can increase IAP
Sedation and analgesia can reduce muscle tone and decrease IAP to less detrimental levels
While such therapy would appear prudent, no prospective trials have been performed evaluating the benefits and risks of sedation and analgesia in IAH/ACS
RECOMMENDATIONS:NEUROMUSCULAR BLOCKADE: RECOMMENDATIONS: NEUROMUSCULAR BLOCKADE A brief trial of neuromuscular blockade (NMB) may be considered in selected patients with mild to moderate IAH while other interventions are performed to reduce IAP (Grade 2C)
Diminished abdominal wall compliance due to pain, tight abdominal closures, and third-space fluid can increase IAP to detrimental levels
The potential beneficial effects of NMB in reducing abdominal muscle tone must be balanced against the risks of prolonged paralysis
NMB is unlikely to be an effective therapy for patients with severe IAH or the patient who has already progressed to ACS
RECOMMENDATIONS:BODY POSITIONING: RECOMMENDATIONS: BODY POSITIONING The potential contribution of body position in elevating IAP should be considered in patients with moderate to severe IAH or ACS (Grade 2C)
Head of bed elevation can significantly increase IAP compared to supine positioning, especially at higher levels of IAH
Such increases in IAP become clinically significant (increase > 2 mmHg) when the patient’s head of bed exceeds 20 degrees elevation
Supine IAP measurements may underestimate the true IAP if the patient’s head of bed is elevated between measurements
RECOMMENDATIONS: GASTRIC/RECTAL SUCTIONING, PROKINETIC AGENTS: RECOMMENDATIONS: GASTRIC/RECTAL SUCTIONING, PROKINETIC AGENTS No recommendations can be made at this time
Both air and fluid within the hollow viscera can raise IAP and lead to IAH / ACS
Nasogastric and/or rectal drainage, enemas, and even endoscopic decompression can reduce IAP
Prokinetic motility agents such as erythromycin, metoclopromide, or neostigmine can aid in evacuating the intraluminal contents and decreasing the size of the viscera
Insufficient evidence is currently available to confirm the benefit of such therapies in IAH/ACS
RECOMMENDATIONS: FLUID RESUSCITATION: RECOMMENDATIONS: FLUID RESUSCITATION Fluid resuscitation volume should be carefully monitored to avoid over-resuscitation in patients at risk for IAH/ACS (Grade 1B)
Hypertonic crystalloid and colloid-based resuscitation should be considered in patients with IAH to decrease the progression to secondary ACS (Grade 1C)
Fluid resuscitation and “early goal-directed therapy” are cornerstones of critical care management
Excessive fluid resuscitation is an independent predictor of IAH/ACS and should be avoided
The use of goal-directed hemodynamic monitoring should be considered to achieve appropriate fluid resuscitation
RECOMMENDATIONS: DIURETICS & CONTINUOUS HEMOFILTRATION: RECOMMENDATIONS: DIURETICS & CONTINUOUS HEMOFILTRATION No recommendations can be made at this time
Diuretic therapy, in combination with colloid, may be considered to mobilize third-space edema following initial resuscitation and once the patient is hemodynamically stable
Continuous hemofiltration / ultrafiltration may be an appropriate intervention rather than continuing to volume load and increase the likelihood of secondary ACS
These therapies have yet to be subjected to prospective clinical study in IAH/ACS patients
RECOMMENDATIONS: PERCUTANEOUS CATHETER DECOMPRESSION: RECOMMENDATIONS: PERCUTANEOUS CATHETER DECOMPRESSION Percutaneous catheter decompression should be considered in patients with intraperitoneal fluid, abscess, or blood who demonstrate symptomatic IAH or ACS (Grade 2C)
Paracentesis represents a less invasive method for treating IAH/ACS due to free fluid, ascites, air, abscess, or blood
Percutaneous catheter insertion under ultrasound guidance allows ongoing drainage of intraperitoneal fluid and may help avoid the need for open abdominal decompression in selected patients with secondary ACS
RECOMMENDATIONS: ABDOMINAL DECOMPRESSION: RECOMMENDATIONS: ABDOMINAL DECOMPRESSION Surgical decompression should be performed in patients with ACS that is refractory to other treatment options (Grade 1B)
Presumptive decompression should be considered at the time of laparotomy in patients who demonstrate multiple risk factors for IAH/ACS (Grade 1C)
Surgical abdominal decompression has long been the standard treatment for the patient who develops ACS
It represents a life-saving intervention when a patient’s IAH has become refractory to medical treatment options and organ dysfunction and/or failure is evident
RECOMMENDATIONS: DEFINITIVE ABDOMINAL CLOSURE: RECOMMENDATIONS: DEFINITIVE ABDOMINAL CLOSURE No recommendations can be made at this time
Most patients will tolerate primary fascial closure within 5–7 days if decompressed before significant organ failure develops
Management options for the “open abdomen” include split-thickness skin grafting, cutaneous advancement flap (“skin only”) closure, and vacuum-assisted closure techniques
Prospective trials to identify the optimal management technique have yet to be performed
Slide19: IAH/ACS MANAGEMENT ALGORITHM www.wsacs.org
RECOMMENDATIONS: FUTURE RESEARCH: RECOMMENDATIONS: FUTURE RESEARCH Incidence and prevalence estimates of IAH/ACS should be based upon the consensus definitions (Grade 1C)
To facilitate communication of the severity of IAH in future trials, we suggest that mean, median, and maximal IAP values should be provided both on admission and during the study period (Grade 2C)
Previous research has been complicated by the lack of consensus definitions
Use of the definitions and recommendations presented should facilitate the interpretation and comparison of future studies
There is a significant need for well-designed, prospective clinical trials to clarify the many questions and issues that remain unanswered with respect to IAH/ACS
CONCLUSIONS: CONCLUSIONS The WSACS hopes that these evidence-based consensus definitions, recommendations, and algorithms will aid in interpreting past research, improving current patient care, and planning future clinical and basic science research
The WSACS anticipates that these definitions and recommendations will be dynamic and will change as new research becomes available
WORLD SOCIETY OF THE ABDOMINAL COMPARTMENT SYNDROME (WSACS): WORLD SOCIETY OF THE ABDOMINAL COMPARTMENT SYNDROME (WSACS) The WSACS was founded to promote education and research on IAH and ACS
Its membership includes physicians, surgeons, anesthetists, intensivists, nurses, respiratory therapists, and others
For further details, go to: www.wsacs.org