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

OBJECTIVE: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade, and the number of published studies has exploded in recent years. Interpretation of the results and comparison of these studies is difficult, because of incomplete and inconsistent reporting of data and statistics. DESIGN: An international consensus group of multidisciplinary specialists convened at the third World Congress on Abdominal Compartment Syndrome to develop recommendations for research related to the diagnosis and management of IAH and ACS. METHODS: Prior to the conference the authors developed a blueprint for consensus definitions and treatment guidelines which were refined both during and after the conference. RESULTS: Three major types of studies were identified (measurement techniques, epidemiology, and interventions), each with different needs regarding methodology, reporting of data and statistical analysis. CONCLUSIONS: These recommendations are proposed to guide clinical research in the field of IAH and ACS.

Intra-abdominal pressure measurements in lateral decubitus versus supine position.

OBJECTIVE: Intra-abdominal pressure (IAP) has traditionally been measured in the supine position, however, measuring the pressure in lateral semi-recumbent position has not been studied. DESIGN: A single centre prospective 1-day study. PATIENTS: 10 patients admitted for more then 24 hours who were mechanically ventilated and had an indwelling urinary catheter. METHODS: Inclusion criteria included were age > 18 years, sedated to a RASS score of -5 and mechanically ventilated. The pressures were measured via the bladder with the mid-axillary line as zero reference point. When patients were nursed in lateral decubitus, pressures were measured and compared immediately to the supine position. RESULTS: 10 patients were included with a total of 60 measurements.The male/female ratio was 9:1 with a mean APACHE Pi score of 11.5 [95% CI 4.8-22.4], SAPS 2 of 31.5 [95% CI 8.9-35.8] and SOFA score of 4.0 [95% CI 1.8-7.2]. Four patients were medical and 6 were surgical. The mean IAP at different time intervals (morning, afternoon and evening) in lateral and supine position were 10.9 +/- 2.0 (in mmHg) vs 6.6 +/- 3.2 (SD with p < 0.001); 11.0 +/- 4.0 vs 5.4 +/- 2.2 (p < 0.0005) and 11.6 +/- 3.8 vs 7.8 +/- 3.0 (p< 0.001). Overall, the LSP did not change significantly (p= 0.76), but the SP did (p=0.006) with the afternoon reading being significantly lower than the evening measurement. However, the trend in the difference (LSP minus SP) was not significant (p=0.43). CONCLUSION: There was a significant statistical difference in the pressures measured in LSP versus SP.The LSP position should not be used to measure IAP.

Clinical awareness of intra-abdominal hypertension and abdominal compartment syndrome in 2007.

INTRODUCTION: There has been an exponentially increasing interest in intra-abdominal hypertension (IAH). The aim of this review is to evaluate the evolution in clinical awareness of this syndrome. METHODS: A PubMed (U.S. National Library of Medicine) search and a ScienceDirect (Elsevier B.V.) search of recent literature were performed in order to assess clinical awareness of IAH and abdominal compartment syndrome (ACS). RESULTS: In total, 489 articles and 8 clinical surveys have been identified. The results of the landmark papers and the surveys will be briefly discussed in this review. CONCLUSION: Clinical awareness of ACS is steadily increasing. It is time to pay attention to ACS, but further, it is time to move forward with therapeutic bundles in a multi-centered, outcome trial on IAH/ACS therapy in order to elevate IAH/ACS management to an international standard of care.

Cardiovascular implications of abdominal compartment syndrome.

Cardiovascular dysfunction and failure are commonly encountered in the patient with intraabdominal hypertension or abdominal compartment syndrome. Accurate assessment and optimization of preload, contractility, and afterload, in conjunction with appropriate goal-directed resuscitation and abdominal decompression when indicated, are essential to restoring end-organ perfusion and maximizing patient survival. The validity of traditional hemodynamic resuscitation endpoints, such as pulmonary artery occlusion pressure and central venous pressure, must be reconsidered in the patient with intra-abdominal hypertension as these pressure-based estimates of intravascular volume have significant limitations in patients with elevated intra-abdominal pressure. If such limitations are not recognized, misinterpretation of the patient's cardiac status is likely, resulting in inappropriate and potentially detrimental therapy. Appropriate fluid administration is mandatory as under-resuscitation leads to organ failure and over-resuscitation the development of secondary abdominal compartment syndrome, both of which are associated with increased morbidity and mortality. Volumetric monitoring techniques have been proven to be superior to traditional intra-cardiac filling pressures in directing the appropriate resuscitation of this patient population. Calculation of the "abdominal perfusion pressure", defined as mean arterial pressure minus intra-abdominal pressure, has been shown to be a beneficial resuscitation endpoint as it assesses not only the severity of the patient's intra-abdominal hypertension, but also the adequacy of abdominal blood flow. Application of a goal-directed resuscitation strategy, including abdominal decompression when indicated, improves cardiac function, reverses end-organ failure, and minimizes intra-abdominal hypertension-related patient morbidity and mortality.

Clinical awareness of intra-abdominal hypertension and abdominal compartment syndrome in 2007.

INTRODUCTION: There has been an exponentially increasing interest in intra-abdominal hypertension (IAH). The aim of this review is to evaluate the evolution in clinical awareness of this syndrome. METHODS: A PubMed (U.S. National Library of Medicine) search and a ScienceDirect (Elsevier B.V.) search of recent literature were performed in order to assess clinical awareness of IAH and abdominal compartment syndrome (ACS). RESULTS: In total, 489 articles and 8 clinical surveys have been identified. The results of the landmark papers and the surveys will be briefly discussed in this review. CONCLUSION: Clinical awareness of ACS is steadily increasing. It is time to pay attention to ACS, but further, it is time to move forward with therapeutic bundles in a multi-centered, outcome trial on IAH/ACS therapy in order to elevate IAH/ACS management to an international standard of care.

Cardiovascular implications of abdominal compartment syndrome.

Cardiovascular dysfunction and failure are commonly encountered in the patient with intra-abdominal hypertension or abdominal compartment syndrome. Accurate assessment and optimization of preload, contractility, and afterload, in conjunction with appropriate goal-directed resuscitation and abdominal decompression when indicated, are essential to restoring end-organ perfusion and maximizing patient survival. The validity of traditional hemodynamic resuscitation endpoints, such as pulmonary artery occlusion pressure and central venous pressure, must be reconsidered in the patient with intra-abdominal hypertension as these pressure-based estimates of intravascular volume have significant limitations in patients with elevated intra-abdominal pressure. If such limitations are not recognized, misinterpretation of the patient's cardiac status is likely, resulting in inappropriate and potentially detrimental therapy. Appropriate fluid administration is mandatory as under-resuscitation leads to organ failure and over-resuscitation the development of secondary abdominal compartment syndrome, both of which are associated with increased morbidity and mortality. Volumetric monitoring techniques have been proven to be superior to traditional intra-cardiac filling pressures in directing the appropriate resuscitation of this patient population. Calculation of the "abdominal perfusion pressure", defined as mean arterial pressure minus intra-abdominal pressure, has been shown to be a beneficial resuscitation endpoint as it assesses not only the severity of the patient's intra-abdominal hypertension, but also the adequacy of abdominal blood flow. Application of a goal-directed resuscitation strategy, including abdominal decompression when indicated, improves cardiac function, reverses end-organ failure, and minimizes intra-abdominal hypertension-related patient morbidity and mortality.

Percutaneous endoscopic gastrostomy in patients with an open abdomen.

Percutaneous endoscopic gastrostomy is a commonly performed procedure for enteral access. In the past decade surgeons have used the open abdomen technique with increased frequency for the treatment of intra-abdominal compartment syndrome. Because these patients often have associated malnutrition long-term enteral access is complicated by the massive ventral hernia. We reviewed the records of two patients with an open abdomen who needed long-term enteral access. Both patients had a large midabdominal soft tissue defect, which posed a concern about the technique for gastrostomy creation. Both patients underwent percutaneous endoscopic gastrostomy. In each case the entrance site was located on a portion of intact abdominal wall lateral to the open abdomen tissue defect. No intraoperative or postoperative complications were noted. We conclude that percutaneous endoscopic gastrostomy can be safely performed in patients with an open abdomen. Adherence to standard principles of performing percutaneous endoscopic gastrostomy allows for enteral access in these patients.

Percutaneous dilational tracheostomy: a comparison of single- versus multiple-dilator techniques.

OBJECTIVE: To compare the safety and efficacy of single- vs. multiple-dilator techniques in the performance of percutaneous dilational tracheostomy. DESIGN: Prospective randomized trial. SETTING: Intensive care units at a level 1 trauma center. PATIENTS: Fifty consecutive patients requiring tracheostomy for airway control or prolonged mechanical ventilatory support. INTERVENTIONS: Patients were randomized to receive a percutaneous dilational tracheostomy by either the single- or multiple-dilator technique described by Ciaglia. MEASUREMENTS AND MAIN RESULTS: Percutaneous dilational tracheostomy was performed using the single-dilator technique in 6:01 +/- 3:03 mins and by the multiple-dilator technique in 10:01 +/- 4:26 mins (p <.0006). There were no statistically significant differences in complication rates between the two techniques. No major complications occurred with either technique. CONCLUSION: The single-dilator percutaneous tracheostomy technique is a safe, cost-effective, and more rapidly performed method for bedside tracheostomy in the intensive care unit.

Mathematical coupling does not explain the relationship between right ventricular end-diastolic volume and cardiac output.

OBJECTIVE: To evaluate the clinical significance of mathematical coupling on the correlation between cardiac output and right ventricular end-diastolic volume (RVEDV) through measurement of cardiac output by two independent techniques. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit in a level 1 trauma center. PATIENTS: Twenty-eight critically ill surgical patients who received mechanical ventilation and hemodynamic monitoring with a pulmonary artery catheter. INTERVENTIONS: A pulmonary artery catheter designed to measure right ventricular ejection fraction (RVEF) and cardiac output by the intermittent bolus thermodilution (TDCO) method and continuous cardiac output by the pulsed thermal energy technique was placed. A computerized data logger was used to collect data simultaneously from the RVEF/TDCO system and the continuous cardiac output system. MEASUREMENTS AND MAIN RESULTS: Two hundred forty-nine data sets from 28 patients were compared. There is statistical correlation between TDCO and continuous cardiac output measurements (r = 0.95, p < 0.0001) with an acceptable bias (-0.11 L/min) and precision (+/-0.74 L/min). The correlation was maintained over a wide range of cardiac outputs (2.3-17.8 L/min). There is a high degree of correlation between RVEDV and both TDCO (r = 0.72, p < 0.0001) and independently measured continuous cardiac output (r = 0.68, p < 0.0001). These correlation coefficients are not statistically different (p = 0.15). CONCLUSIONS: The continuous cardiac output technique accurately approximates cardiac output measured by the TDCO method. RVEDV calculated from TDCO correlates well with both TDCO and independently measured continuous cardiac output. Because random measurement errors of the two techniques differ, mathematical coupling alone does not explain the correlation between RVEDV estimates of preload and cardiac output.

Comprehensive trauma patient care by nonphysician providers.

Nonphysician providers are being increasingly used to care for trauma patients. As these complex patients recover, they require meticulous medical management and time-consuming psychosocial care. A retrospective evaluation of a unique patient care service staffed by nonphysician providers is presented. The Intermediate Care Service is designed to facilitate the management and long-term placement of trauma patients who no longer require intensive care while recovering from their injuries. The new diagnoses, physician order changes, and disposition of 93 patients cared for during a 6-month period are described. Most patients were admitted with neurologic injury. The most common new diagnosis was constipation; the most frequent new orders related to medications, including bowel management, and rehabilitation consultations. All patients were discharged from the hospital. The Intermediate Care Service represents a unique and valuable model for the collaborative management of complex trauma patients.

Abdominal perfusion pressure: a superior parameter in the assessment of intra-abdominal hypertension.

OBJECTIVE: To assess the clinical utility of abdominal perfusion pressure (mean arterial pressure minus intra-abdominal pressure) as both a resuscitative endpoint and predictor of survival in patients with intra-abdominal hypertension. METHODS: 144 surgical patients treated for intra-abdominal hypertension between May 1997 and June 1999 were retrospectively reviewed. Multivariate logistic regression and receiver operating characteristic curve analysis of common physiologic variables and resuscitation endpoints were performed to determine the decision thresholds for each variable that predict patient survival. RESULTS: Abdominal perfusion pressure was statistically superior to both mean arterial pressure and intravesicular pressure in predicting patient survival from intra-abdominal hypertension and abdominal compartment syndrome. Multiple regression analysis demonstrated that abdominal perfusion pressure was also superior to other common resuscitation endpoints, including arterial pH, base deficit, arterial lactate, and hourly urinary output. CONCLUSION: Abdominal perfusion pressure appears to be a clinically useful resuscitation endpoint and predictor of patient survival during treatment for intra-abdominal hypertension and abdominal compartment syndrome.

A structured curriculum for improved resident education in statistics.

Many resident physicians do not receive sufficient education in statistical theory and study design to allow them to effectively interpret and apply the medical literature to patient care. A survey of 62 surgical residency programs identified that only 33 per cent include formal statistics teaching in their curricula. A structured curriculum was formulated to introduce surgical residents to basic statistical theory, common statistical tests, and study design. Lectures were integrated into an existing monthly journal club in which manuscripts reviewed were used to illustrate the statistical concepts taught. Knowledge improvement was determined using a multiple choice test given before and after completion of the curriculum. Mean test scores increased significantly as a result of the curriculum (P < 0.004). Formal statistics education using a structured curriculum significantly improves resident physician knowledge of statistical theory and study design. Such teaching can be easily integrated into a residency program's existing curriculum.

An unusual case of corneal perforation secondary to Pseudomonas keratitis complicating a patient's surgical/trauma intensive care unit stay.

We report a case of corneal perforation secondary to bacterial keratitis caused by Pseudomonas aeruginosa in a trauma patient in our intensive care unit. A 43-year-old man was involved in a motorcycle crash and suffered multiple injuries necessitating a prolonged intensive care unit (ICU) stay. Subsequently P. aeruginosa was cultured from his sputum, blood, and open abdomen. He developed a bacterial keratitis in his right eye, which also grew P. aeruginosa. This infection rapidly progressed to corneal perforation requiring a Gunderson conjunctival flap and lateral tarsorrhaphy in addition to aggressive antibiotic treatment. At the time of discharge from the hospital the patient had the return of vision to light only in his right eye. Corneal perforation is an unusual event in the ICU. Prevention or early detection of bacterial keratitis with aggressive antibiotic treatment is needed to prevent such complications. Pseudomonas is one of the more virulent organisms that can infect the cornea and early identification is paramount for a good outcome. Management of this complicated case is discussed and the limited amount of literature on nosocomial bacterial keratitis in the ICU is reviewed.

Life-threatening nail gun injuries.

The use of pneumatic and explosive cartridge-activated nail guns is common in the construction industry. The ease and speed of nailing these tools afford enhance productivity at the cost of increased potential for traumatic injury. Although extremity injuries are most common, life-threatening injuries to the head, neck, chest, or abdomen and pelvis may occur. During a 20-month period, eight potentially life-threatening nail gun injuries were admitted to a Level I trauma center, including injuries to the brain, eye, neck, heart, lung, and femoral artery. Mechanism of injury included nail ricochet, nail gun misuse due to inadequate training, and successful suicide. Nail guns have significant potential for causing severe debilitating injury and death. These findings indicate a need for improved safety features and user education. The various types of nail guns, their ballistic potential, and techniques for operative management are discussed.

Ingested endotracheal tube in an adult following intubation attempt for head injury.

General surgeons are often consulted for assistance in the management of ingested foreign bodies. Deglutition of an endotracheal tube is an unusual complication of airway management. In these cases, the artificial airway is "lost" when it becomes lodged deep into the esophagus. Endoscopic extraction has been described as therapeutic. We report a case in which prehospital endotracheal intubation attempt for the management of closed head injury resulted in a swallowed endotracheal tube. The tube remained undetected until radiographs were performed for a second unrelated traumatic event 2 years later. Endoscopic extraction was unsuccessful, due to rigidity of the tube. Surgical extraction via gastrotomy was uneventful. Surgeons involved in trauma and other emergency settings should be aware of this complication and options in management.

Air travel following traumatic pneumothorax: when is it safe?

The safety of air travel for patients sustaining a recent traumatic pneumothorax has long been a subject of debate. The Aerospace Medicine Association has suggested that patients should be able to fly 2 to 3 weeks after radiographic resolution of their pneumothorax. To validate these recommendations, a prospective study was performed. Twelve consecutive patients with recent traumatic pneumothorax expressing a desire to travel by commercial airline were evaluated. Ten patients waited at least 14 days after radiographic resolution of their pneumothorax before air travel (mean, 17.5+/-4.9 days), and all were asymptomatic in-flight. One of two patients who flew earlier than 14 days developed respiratory distress in-flight, with symptoms suggestive of a recurrent pneumothorax. We conclude that commercial air travel appears to be safe 14 days following radiographic resolution of a traumatic pneumothorax.

The underestimated impact of personal watercraft injuries.

The popularity of personal watercraft is steadily increasing, as are injuries related to their use. Many of these injuries are not reported to law enforcement agencies, and available personal watercraft injury statistics are suspected to be inaccurate. All personal watercraft-related injuries treated within a four-hospital system (including the regional Level I trauma center) between January 1993 and December 1997 were retrospectively identified. Patient demographics, accident mechanism, injuries sustained, tourist status, outcome, and economic data were collected and compared with available government statistics for the same time period. Sixty-eight consecutive patients injured during personal watercraft use were identified. Of these, 78 per cent were treated and released, whereas 22 per cent required inpatient management. Fractures and soft tissue injuries were the most common injuries sustained. Ninety-seven per cent of patients were discharged home. There was one fatality. Comparison with state and federal statistics identified that personal watercraft injuries are significantly underreported and have an estimated yearly economic impact of more than $235 million. Personal watercraft injuries represent an increasing source of watersport-related trauma. Government statistics on personal watercraft injuries do not accurately reflect the true incidence and economic impact of such trauma. Mandatory educational programs and increased legislation to improve personal watercraft safety should be promoted.

Preload assessment in patients with an open abdomen.

BACKGROUND: Intra-abdominal hypertension and abdominal compartment syndrome cause significant morbidity and mortality in surgical and trauma patients. Maintenance of intravascular preload and use of open abdomen techniques are essential. The accuracy of pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) in patients with intra-abdominal hypertension has been questioned. METHODS: Twenty surgical and trauma patients with intra-abdominal hypertension requiring open abdominal decompression were monitored using volumetric thermodilution pulmonary artery catheters. Hemodynamic, oxygenation, inspiratory, and intravesicular pressure measurements were collected prospectively. PAOP, CVP, and right ventricular end-diastolic volume index (RVEDVI) were compared as estimates of preload status. RESULTS: Multiple regression analysis demonstrated that cardiac index correlated significantly better with RVEDVI (r = 0.69) than with PAOP (r = -0.27) or CVP (r = -0.28) during resuscitation after open abdominal decompression (p < 0.0001). CONCLUSION: RVEDVI is superior to PAOP and CVP as an estimate of preload status in patients with an open abdomen.

Right ventricular end-diastolic volume index as a predictor of preload status in patients on positive end-expiratory pressure.

OBJECTIVE: To evaluate the clinical utility of right ventricular end-diastolic volume index (RVEDVI) and pulmonary artery occlusion pressure (PAOP) as measures of preload status in patients with acute respiratory failure receiving treatment with positive end-expiratory pressure. DESIGN: Prospective, cohort study. SETTING: Surgical intensive care unit in a Level I trauma center/university hospital. PATIENTS: Sixty-four critically ill surgical patients with acute respiratory failure. INTERVENTIONS: All patients were treated for acute respiratory failure with titrated levels of positive end-expiratory pressure (PEEP) with the goal of increasing arterial oxygen saturation to > or =0.92, reducing FIO2 to <0.5, and reducing intrapulmonary shunt to < or =0.2. Serial determinations of RVEDVI, PAOP, and cardiac index (CI) were recorded. MEASUREMENTS AND MAIN RESULTS: Two hundred-fifty sets of hemodynamic variables were measured in 64 patients. The level of PEEP ranged from 5 to 50 cm H2O (mean 12+/-9 [SD] cm H2O). At all levels of PEEP, CI correlated significantly better with RVEDVI than with PAOP. At levels of PEEP > or =15 cm H2O, CI was inversely correlated with PAOP, but remained positively correlated with RVEDVI. CONCLUSIONS: CI correlates significantly better with RVEDVI than PAOP at all levels of PEEP up to 50 cm H2O. RVEDVI is a more reliable predictor of volume depletion and preload recruitable increases in CI, especially in patients receiving higher levels of PEEP where PAOP is difficult to interpret.