William P. Riordan

Eastern Association for the Surgery of Trauma: A Review of the Management of the Open Abdomen-Part 2 "Management of the Open Abdomen"

During the course of the last 30 years, several authors have contributed their clinical experience to the literature in an effort to describe the various management strategies for the appropriate use of the open abdomen technique. There remains a great degree of heterogeneity in the patient population, and the surgical techniques described. The open abdomen technique has been used in both military and civilian trauma and vascular and general surgery emergencies. Given the lack of consistent practice, the Eastern Association for the Surgery of Trauma (EAST) Practice Management Guidelines Committee convened a study group to establish recommendations for the use of open abdomen techniques in both trauma and nontrauma surgery. This has been a major undertaking and has been divided into two parts. The EAST practice management guidelines for the open abdomen part 1 “Damage Control” have been published.1 During the development of the open abdomen part II “Management of the Open Abdomen,” the current literature remains contentious at best, current methods of treatment continue to change rapidly, and patient populations are so heterogeneous that clear recommendations could not be provided. What follows is a thorough review of the current literature for the management of the open abdomen: part 2 “Management of the Open Abdomen” and provides clinical direction regarding the following specific topics.

Early Loss of Heart Rate Complexity Predicts Mortality Regardless of Mechanism, Anatomic Location, or Severity of Injury in 2178 Trauma Patients

BACKGROUND Reduced heart rate (HR) complexity (e.g., a lack of randomness or unpatterned variability) is an established predictor of trauma patient mortality. However, this finding has not been validated across the diverse spectrum of traumatic injury, and underlying mechanisms of this relationship are poorly understood. MATERIALS AND METHODS Two thousand one hundred seventy-eight trauma patients were admitted directly to the intensive care unit (ICU), and had sufficient (>6h) continuous integer heart rate data within the first d. Patients were stratified by location of isolated severe injury (head, torso, both, or neither), primary mechanism (blunt or penetrating), and probability of survival, an accepted scoring system based on age, admission vital signs, and injury type and severity. HR multiscale entropy (MSE) was calculated (sum of scales, Costas algorithm, physionet.org, m=2, r=0.15) to estimate complexity. Univariate analysis was performed by comparing MSE between survivors and nonsurvivors in each subgroup. Multivariate analysis incorporated logistic regression to characterize the relationship between MSE and risk of death, controlling for probability of survival. The MSE odds ratios (OR) and area under the receiver operator curve (AUC) were calculated. RESULTS Reduced MSE was significantly associated with increasing mortality, and was independent of probability of survival in all multivariate analyses (OR 0.87-0.94). This range of odds ratios implies that a patient with an MSE of 15 has roughly a 2- to 6-fold increase in odds of death versus a patient with an MSE of 25. The relationship between MSE and death was moderately stronger in patients with isolated severe head injury versus torso injury, and significantly stronger in patients with penetrating versus blunt mechanism of injury. MSE measured early in the hospital stay remained a robust predictor of mortality in all subgroups, even stratified by narrow ranges of probability of survival. CONCLUSIONS Early reduction of heart rate complexity is an important risk factor across diverse injury etiology. This suggests common underlying physiologic mechanisms linking the loss of biologic complexity to death.

Cardiac uncoupling and heart rate variability are associated with intracranial hypertension and mortality: a study of 145 trauma patients with continuous monitoring.

BACKGROUND A noninvasive tool reflecting intracranial hypertension (ICH) should prompt early invasive monitoring and reduce secondary injury after traumatic brain injury. We hypothesized that integer heart rate variability (HRV) may be associated with rises in intracranial pressure (ICP); changes in HRV may precede changes in ICP; and both increases in ICP and cardiac uncoupling (low HRV) predict mortality. METHODS Of 14,330 consecutive trauma admissions, 291 of these patients had an injury requiring intracranial monitoring. Of these patients 145 had simultaneous HRV and ICP monitoring with a Camino monitor. ICP and heart rate (HR) data were matched and divided into 5-minute intervals (N = 117,956, representing 24.4 million HR and ICP data points). In each interval, the median ICP, and SD of HR (HRSD5) were calculated. Cardiac uncoupling was defined as an interval with HRSD5 between 0.3 bpm and 0.6 bpm. Cardiac uncoupling was compared between ICP categories using the Wilcoxon Rank-Sum test, and logistic regression was used to assess the continuous relationship between ICP and risk of uncoupling. RESULTS Cardiac uncoupling increases as ICP increases (p < 0.001). Uncoupling nearly doubles when comparing acceptable ICP (<20 mm Hg, 11% uncoupled) to ICH (31-50 mm Hg, 18% uncoupled), with uncoupling = 13% in the intermediate group (ICP 21-30 mm Hg). This trend continues at the level of malignant ICH (>50 mm Hg, 22% uncoupled). CONCLUSION Cardiac uncoupling increases as ICP increases. Both cardiac uncoupling and ICH predict mortality. Cardiac uncoupling may precede ICH but is not yet an indication for invasive monitoring.

Does regionalization of acute care surgery decrease mortality

BACKGROUND During the initial development of an Emergency General Surgery (EGS) service, severity of illness (SOI) can be expected to be high and should decrease as the service matures. We hypothesize that a matured regional EGS service would show decreasing mortality and length of stay (LOS) over time. METHODS We performed a retrospective study of a prospectively collected EGS registry data from 2004 to 2009. Patients were included if they had been discharged from the EGS service and were stratified by year of discharge. Systemic inflammatory response syndrome, sepsis, shock, peritonitis, perforation, and acute renal failure were used as markers of SOI. Patients were defined as high acuity if they had one or more of these SOI markers. Differences in mortality, LOS, intensive care unit admissions, SOI, charges, and distance were compared across and between years using nonparametric statistical tests (Fishers exact, Wilcoxon rank-sum, and Kruskal-Wallis tests). RESULTS A total of 3,439 patients met study criteria. The mean age was 47 years ± 17.5 years. The majority of the patients were female (1,813, 47.3%). The overall LOS was 6.4 days ± 9.4 days (median, 4 days). In all, 2,331 (67.8%) of the patients underwent operation. Over the course of the study period, the SOI indicators stabilized at between 13% and 17% of the patient population with at least one indicator. During that time period, mortality steadily decreased from 4.9% to 1.3% (p < 0.5). CONCLUSION Despite consistently high SOI, a dedicated and matured EGS service demonstrated a decrease in mortality and LOS.

Acute Care Surgery Program: Mentoring Fellows and Patient Outcomes

BACKGROUND Acute care surgery programs have demonstrated that trauma patient outcomes have not changed with the addition of emergency general surgery (EGS) responsibilities. EGS patient outcomes and the mentoring of fellows on EGS service have not been previously studied. We hypothesize that EGS patient outcomes would not differ by provider on a service driven by evidence-based medicine (EBM) protocols. PATIENTS AND METHODS Retrospective study of prospectively collected EGS repository. academic level I trauma center, and regional EGS referral center from 2003 to 2007. There were 14 faculty and seven fellows during the study period. EGS coverage is a full week, with weeknight coverage by the in-house trauma/EGS faculty. Fellows are mentored by designated faculty while on service, who discuss patients, assist in the OR, or assume care if necessary. Data collected included age, gender, LOS, ICU LOS, ventilator days, disposition (home/rehab), and infectious complications(IC) (VAP, BSI, UTI, SSI). Primary outcome was mortality. RESULTS 1769 patients met study criteria. The mean age was 47.1 (+/-18), 47% were males. The average ICU LOS was 2.9 d (+/-7.9), ventilator d 2.6 (+/-7.6); 82.1% were discharged home and 13.7% were referred to rehab. There was no statistical difference in mortality, LOS, ICU LOS, disposition, ventilator d, and IC between faculty and fellow providers. CONCLUSIONS An EGS service with EBM protocols assures consistency in patient outcomes independent of provider level: faculty or fellows. Our model for mentoring fellows did not decrease EGS patient outcomes.

Triaging to a regional acute care surgery center: distance is critical.

BACKGROUND In acute care surgery, predicting mortality is important to determine appropriate patient transfer to a regional emergency general surgery (EGS) center. We hypothesized that distance to a referral center and severity of illness (SOI) would be predictors of death. METHODS We performed a retrospective analysis of a prospectively collected EGS registry from 2004 to 2008. The study population consisted of all patients discharged from the EGS service with an available home zip code in the registry. Study data included age, gender, length of stay (LOS), intensive care unit (ICU) LOS, distance between our facility and patient home zip code, and need for operative management. Systemic inflammatory response syndrome/sepsis/shock, peritonitis, perforation, and acute renal failure were used as SOI indicators. Mortality at discharge was the primary outcome. Patients were stratified by survival and compared using non-parametric statistical tests. Logistic regression assessed the simultaneous contribution of age, SOI, and distance to risk of death. RESULTS A total of 3,439 patients met study criteria. Females slightly outnumbered males (1,813, 52.7%) with a median age of 47 years. The overall LOS was 6.4 days±9.3 days, and 2,331 (67.8%) of the patients underwent operation. Mean distance was 41.5 miles±51.2 miles (median, 22.2). Overall mortality was 2.7%. Increasing distance, age, and presence of SOI indicators were associated with mortality in univariable analyses. In multivariable logistic regression controlling for patient age and SOI, increasing distance in miles was related to increased mortality (odds ratio, 1.005; p<0.001). This odds ratio equates to a doubling in odds of death for each 132 miles between our center and the patients home zip code. CONCLUSION Age, SOI, and distance from a regional referral center explain much of the variation in mortality and can be used for triage to regional EGS centers.

SIMON: A Decade of Physiological Data Research and Development in Trauma Intensive Care

SIMON (Signal Interpretation and MONitoring) continuously collects and processes bedside medical device data. As of December 2009, SIMON has monitored over 7,630 trauma intensive care unit (TICU) patients, representing approximately 731,000 hours of continuous monitoring, and is currently operational on all TICU beds at Vanderbilt University Medical Center. Parameters captured include heart rate, blood pressures, oxygen saturations, cardiac function variables, intracranial and cerebral perfusion pressures, and EKG waveforms. This repository supports research to identify “new vital signs” based on features of patient physiology observable through dense data capture and analysis, with the goal of improving predictions of patient status. SIMONs alerting and reporting capabilities include web display, sentinel event notification, and daily summary reports of traditional and new vital sign statistics. This allows discoveries to be rapidly tested and implemented in a working clinical environment. The work details SIMONs technology and corresponding design requirements to realize the value of dense physiologic data in critical care.

All bleeding stops: how we can help...

Rossaint and colleagues provide the critical care community with a comprehensive review of evidence-based data in an updated European guideline on management of bleeding following major trauma. In addition to reevaluating and grading recommendations carried forward from their previous work, they present new recommendations in areas such as coagulation support and monitoring, tourniquet usage, calcium, and desmopressin. Many of the recommendations are appropriately broad enough to promote the use of clinical judgment in the application of the guidelines.

Trimethoprim-Associated Hyperkalemia in a Young Trauma Victim

To the Editor: Trimethoprim-sulfamethoxazole (TMPS) is a commonly administered antimicrobial agent. Traditionally, this combination has been used for the treatment of urinary tract infection [1]; however, TMPS also is commonly used for prophylaxis against Pneumocystis jiroveci pneumonia in patients with human immunodeficiency virus (HIV) infection and in solid organ and stem cell recipients [2]. The agent also is the treatment of choice for some opportunistic infections other than Pneumocystis jiroveci and can be used against infections caused by Legionella spp., Toxoplasma gondii, Listeria monocytogenes, and Nocardia spp. Recently, the drug has been advocated as an excellent option for infections with community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA) [3, 4]. Finally, TMPS can be used in the setting of nosocomial infections caused by Stenotrophomonas maltophilia and Acinetobacter spp. [5, 6]. Side effects of TMPS are attributable mostly to the sulfonamide component and include hepatotoxicity, nephrotoxicity, myelotoxicity, toxic epidermal necrolysis, and Stevens-Johnson syndrome, as well as many other less recognized complications [7, 8]. Less commonly, patients develop side effects attributable to trimethoprim, the most notable being hyperkalemia. Polyuria and hyperkalemia associated with trimethoprim are believed to originate from its being structurally related to amiloride, which has a potassium-sparing diuretic action [9-14]. We report the association of polyuria and severe hyperkalemia with TMPS use in a critically injured trauma victim. A 36-year old woman was involved in a motor vehicle crash and sustained severe closed head injury with frontal lobe intracerebral hemorrhage, multiple facial and skull fractures, as well as bilateral posterior arch fractures of C1 and an odontoid fracture. She had been taken by emergency medical services from the scene to an outside hospital, where she was intubated because of a Glasgow Coma Scale score (GCS) of nine. Thereafter, she was airlifted to our center. After initial stabilization, she underwent sequential operative repair of her facial and skull fractures and received clindamycin for perioperative prophylaxis. Her vertebral fractures were managed nonoperatively. She recovered slowly from her injuries but required both percutaneous tracheostomy and placement of a percutaneous endoscopic gastrostomy secondary to a persistently altered GCS, facial swelling, and a high-risk airway secondary to her cervical fractures. One week after admission, she developed pneumonia, which was treated empirically with doripenem, tobramycin, and vancomycin. She underwent bronchoalveolar lavage, and Stenotrophomonas maltophilia and Acinetobacter baumannii, both sensitive to TMPS, were isolated. Thus, TMPS was started at a dose of 224 mg q 6 h. Two days after initiation of TMPS therapy, the patient developed polyuria, and her serum potassium started to increase, peaking at 6.1 mg/dL (Fig. 1). Kayexalate and insulin were administered, and 40 mg of furosemide was given; however, the serum potassium concentration decreased only to 5.8 mg/dL. No evidence of myoglobinuria or compartment syndrome was present, and renal function (blood urea nitrogen/creatinine clearance) appeared normal. At this stage, TMPS was recognized as a potential cause of the hyperkalemia, the drug was stopped, and the serum potassium declined to 4.8 mg/dL. Her pneumonia had improved clinically, with improvement in her chest radiograph, temperature curve, white blood cell count, and PaO2:FIO2 (P:F) ratio. Additional doses of furosemide were given, and her serum potassium concentration normalized within 36 h. The patient’s further hospital course was uncomplicated, and she was discharged to a rehabilitation facility one week after the event. Development of hyperkalemia should be recognized as a potentially dangerous side effect of TMPS therapy [9-14]. Although this type of toxicity has been described most commonly as a consequence of high-dose intravenous TMPS, cases following oral therapy using low-dose TMPS also have been published [9, 11]. In one study, the incidence of this side effect was seven fold higher than with other antibiotics such as betalactams or fluoroquinolones [15]. Predisposing factors include renal failure, advanced age, use of angiotensin converting enzyme (ACE) inhibitors, and exposure to some drugs, such as spironolactone [15-17]. In the case presented here, hyperkalemia developed within 48 h after the start of drug exposure, which is earlier than in many published cases. However, numerous confounding treatments may contribute to a more rapid increase in potassium. Corticosteroids have been advocated to abrogate this specific side effect of trimethoprim, and fludrocortisone has been used as treatment of the condition

Laparoendoscopic evaluation and treatment of massive pneumoperitoneum occurring 1 year after gastrostomy tube removal

A 48-year-old man presented with massive pneumoperitoneum approximately 1 year after removal of a gastrostomy tube. A combined laparoscopic and endoscopic evaluation was used to identify and resect the gastric perforation at the previous gastrostomy site. To our knowledge, this is the longest interval reported in the literature for development of pneumoperitoneum after percutaneous endoscopic gastrostomy. A laparoendoscopic approach to evaluation and treatment of pneumoperitoneum in this setting is described.