Intra-abdominal hypertension and abdominal compartment syndrome in burn patients

Abdominal compartment syndrome in trauma resuscitation

PURPOSE OF REVIEW

Swelling is inexorably linked to shock and resuscitation in trauma. In many forms, swelling complicates and interacts with traumatic injury to raise pressures in the abdomen, resulting in intraabdominal hypertension, which may overtly manifest as abdominal compartment syndrome (ACS) driving multiple organ failure. Despite renewed clinical interest in posttraumatic intraabdominal pressure, there remains a chiasm between knowledge of the risks and clinical interventions to mitigate them. This review provides a concise overview of definitions, risk factors, diagnosis and management using an illustrative trauma case.

RECENT FINDINGS

Intraabdominal pressure commonly increases following trauma, wherein ACS may manifest earlier than generally appreciated and complicate other insults such as shock and hemorrhage. Contemporary resuscitation strategies may exacerbate intraabdominal hypertension, particularly massive crystalloid resuscitation. Although unproven, the recent transition to crystalloid restriction and high plasma resuscitation strategies may influence the prevalence of ACS. Nonetheless, aggressive intraabdominal pressure monitoring should be mandatory in the critically ill. Despite potential nonoperative options, decompressive laparotomy remains the only definitive but often morbid treatment.

SUMMARY

ACS results from many dysfunctions acting in concert with each other in self-propagating vicious cycles. Starting with greater awareness, it is imperative that the growing knowledge should be translated into clinical practice.

The impact of opioid administration on resuscitation volumes in thermally injured patients

Administration of resuscitation volumes far beyond the estimates established by burn-body weight resuscitation formulas has been well documented. The reasons behind this increase are not clear. We sought to determine if our resuscitation volumes had increased and, if so, what factors were related to their increase. A retrospective chart review identified 154 patients admitted with burns greater than 20% of their BSA during the years of 1975-1976 (period 1), 1990-1991 (period 2), and 2006-2007 (period 3). Charts were reviewed for total fluids (crystalloid, colloid, and blood products) and opioids given before admission, during the first 8 hours of treatment, the next 16 hours of treatment, and the following 24 hours of treatment. Opioids were converted to opioid equivalents (OE). Multiple regression analysis was performed to determine the effects of variables of interest and control for confounders. Significance was assumed at the P < .05 level. Resuscitation fluid volumes increased significantly among adults from 3.97 ml/kg/%BSA during the first period to 6.40 ml/kg/%BSA during the third period (P < .01). The same trend in children <30 kg was not seen (P = .72). Fluid administered during the first 24 hours was significantly associated with age, BSA, intubation, latter two study periods, and opioid administration. Fluid administration was consistently associated with opioid administration at all measured time points. At 24 hours postburn, patients who received 2 to 4 OE/kg required an average of additional 3,650 +/- 1,704 ml of fluid, those receiving 4 to 6 OE/kg had required an average of 25,154 +/- 4,386 ml, and those who received >6 OE kg had required an average of 32,969 +/- 3,982 ml. In this single center retrospective study, we have shown a statistically significant increase in resuscitation fluids (from 1975 to 2007) and an association of resuscitation volumes with opioids. Opioids have been shown to increase resuscitation volumes in critically ill patients through both central and peripheral effects on the cardiovascular system. Because increased fluid resuscitation has been associated with adverse consequences in other studies, further research on alternative pain control strategies in thermally injured patients is warranted.

Linea Alba Fasciotomy: A Novel Alternative in Trauma Patients with Secondary Abdominal Compartment Syndrome

Polytrauma patients needing aggressive resuscitation can develop intra-abdominal hypertension (IAH) with subsequent secondary abdominal compartment syndrome (SACS). After patients fail medical therapy, decompressive laparotomy is the surgical last resort. In patients with severe pancreatitis SACS, the use of linea alba fasciotomy (LAF) is an effective intervention to lower IAH without the morbidity of laparotomy. A pilot study of LAF was designed to evaluate its benefit in patients with SACS polytrauma. We conducted an observational study of blunt injury polytrauma patients undergoing LAF. Variables measured before and after LAF included intra-abdominal pressure (IAP, mmHg), abdominal perfusion pressure (APP, mmHg), right ventricular end diastolic volume index (RVEDVI, mL/m2), and ejection fraction. Of the five trauma patients with SACS, the mean age was 36 ± 17, four (80%) male with an Injury Severity Score of 27 ± 9. Pre- and post-LAF, IAP was 20.6 ± 4.7 and 10.6 ± 2.7 ( P < 0.0001), APP 55.2 ± 5.5 and 77.6 ± 7.1 ( P < 0.0001), RVEDVI 86.4 ± 9.3 and 123.6 ± 11.9 ( P < 0.0001), and EF 27.6 ± 4.2 and 40.8 ± 5 ( P < 0.0001), respectively. One patient needed full decompression for bile ascites from unrecognized liver injury. Linea alba fasciotomy, as a first-line intervention before committing to full abdominal decompression in patients with SACS trauma, improved physiological variables without mortality Consideration for LAF as a bridge before full abdominal decompression needs further evaluation in patients with polytrauma SACS.

Mechanical ventilation and fluid retention in burn patients

BACKGROUND

Burn patients with inhalation injury (INHI) require more fluid resuscitation than patients without INHI. However, the relation between INHI and fluid resuscitation may be confounded by a ventilation-induced increase in fluid retention. We therefore evaluated whether INHI was independently of continuous positive pressure ventilation (CPPV) associated with increased fluid retention.

METHODS

One hundred eighty-six patients with burns of >20% of total body surface area admitted to the Beverwijk Burns Center (1995-2006) were retrospectively studied. Cumulative fluid balance, defined as the total volume of fluids administered from the time of admission minus the total volume of fluids collected from each patient, was calculated at the end of days 3 (FB3) and 7 (FB7) postburn. The population was divided into three groups: (1) INHI-CPPV- (no INHI, no ventilation; n = 75); (2) INHI-CPPV+ (no INHI with ventilation; n = 62); and (3) INHI+CPPV+ (INHI with ventilation; n = 49). Analyses were corrected for differences in age, weight, and % total body surface area.

RESULTS

Patients who were mechanically ventilated were older and had more extensive burns than those who were not ventilated. Baseline characteristics of patients without INHI who were treated by CPPV were similar to patients with INHI, also treated by CPPV. FB3 was significantly higher in patients without INHI who were ventilated compared with nonventilated patients (13.4 +/- 5.8 L vs. 23.1 +/- 10.6 L for INHI-CPPV- and INHI-CPPV+ respectively, p = 0.001). However, fluid balance was not additionally affected by the presence of INHI. The difference in fluid retention between nonventilated and ventilated patients was also seen on day 7 (22.1 +/- 9.4 L vs. 34.2 +/- 15.9 L for INHI-CPPV- and INHI-CPPV+, respectively, p = 0.001).

CONCLUSION

These results suggest that increased fluid retention, which is conventionally associated with INHI, is due to the effects of ventilation and not to the effects of INHI itself. This warrants a closer evaluation of patients who are ventilated in the absence of INHI, with a view to early extubation.

Component separation technique for abdominal wall reconstruction in burn patients with decompressive laparotomies

BACKGROUND

Component separation technique has been used successfully in ventral hernia repair occurring after damage control surgery. Abdominal compartment syndrome, seen in severely injured burn patients, frequently requires decompressive laparotomy. The patient is at risk during this time not only for burn injury complications but also for those from an open abdomen.

METHODS

This report presents the successful application of the component separation technique for early closure of decompressive laparotomies in patients with >75% total body surface area burn, which included the abdominal wall.

RESULTS

Skin flaps (necrotic/burned skin) overlying the abdominal wall fascia were raised bilaterally at the costal margin, from the anterior superior iliac spine inferiorly to the ribs superiorly. An incision was made just lateral to the rectus sheath through the aponeurosis of the external oblique muscle. With this, the fascia was mobilized to the middle with no tension. With no elevation of the patient's intrathoracic pressure on closure of the abdomen, multiple no. 2 Ethibond fascial figure of eight sutures closed the abdomen. Skin flaps were excised, so that grafting of the abdominal wall could occur.

CONCLUSION

Burn patients, who required decompressive laparotomies for abdominal compartment syndrome in response to massive fluid resuscitation, tolerated early closure by the modified component separation technique. This markedly improved the care of these critically burned individuals, allowing for less third space fluid loss, less difficulty in management of the open abdominal wound, along with decreased risk of potential enterocutaneous fistula and intraabdominal abscess formation.

Fluid resuscitation of the thermally injured patient

Increased capillary permeability and reduced plasma colloid osmotic pressure following burn injury result in hypovolemia and development of edema in the burn and nonburn tissues. Replenishment of the intravascular deficit with crystalloid fluid has been the mainstay of resuscitation for the better part of four decades. A progressive but as yet unexplained trend toward provision of resuscitation volumes well in excess of those predicted by the Parkland formula, associated with numerous edema-related complications, has been repeatedly observed recently. Correction of this phenomenon, called fluid creep, will likely revolve around several strategies, which may include tighter control of titration, re-emergence of colloids and hypertonic salt solutions, and possibly the use of adjunctive markers of resuscitation other than urinary output.

An historical perspective on advances in burn care over the past 100 years

The accelerated pace of clinical and laboratory research over the past century and application of the research findings to patient care have resulted in unprecedented survival of burned patients in all age groups. Resuscitation based on an understanding of the nature and magnitude of the multisystem response to injury now prevents burn shock; effective topical antimicrobial chemotherapy and early excision prevent wound toxemia and sepsis; biologic and bioengineered dressings compensate for the missing skin; and broad spectrum metabolic support regimens prevent exhaustion and accelerate convalescence. Rehabilitation programs have also been developed to restore physical function and permit the burn patient to reenter society as a productive individual.

Recurrent Abdominal Compartment Syndrome: An Inciting Factor of the Second Hit Phenomenon

Intra-abdominal hypertension (IAH) after damage control laparotomy (DCL) is not unusual and because of this, patients are treated with open-abdomen techniques to prevent abdominal compartment syndrome (ACS). The occurrence of recurrent ACS (R-ACS) after abdominal wall closure under tension in patients managed with DCL can be a trigger factor for second hit syndrome. Outcomes in this subset have not been previously described. In this 1-year retrospective study of severely injured patients in a Level I trauma center managed with DCL and sequential abdominal wall closure, 26 patients were identified. After attempted abdominal wall closure, 13 (50%) patients had R-ACS and 13 (50%) non-R-ACS. R-ACS patients had a statistically significant higher incidence of multisystem organ failure, acute respiratory distress syndrome, and sepsis as well as requiring longer ventilator support and longer hospital length of stay. We concluded that failure to recognize and treat IAH with development of R-ACS after tension abdominal wall closure in patients with DCL will trigger the second hit syndrome with increased risk of morbidity. Institution of a management algorithm with intra-abdominal pressure/abdominal perfusion pressure surveillance at the time of abdominal wall closure can potentially ameliorate complications.

Critical care of the burn patient: the first 48 hours

OBJECTIVE

The goal of this concise review is to provide an overview of some of the most important resuscitation and monitoring issues and approaches that are unique to burn patients compared with the general intensive care unit population.

STUDY SELECTION

Consensus conference findings, clinical trials, and expert medical opinion regarding care of the critically burned patient were gathered and reviewed. Studies focusing on burn shock, resuscitation goals, monitoring tools, and current recommendations for initial burn care were examined.

CONCLUSIONS

The critically burned patient differs from other critically ill patients in many ways, the most important being the necessity of a team approach to patient care. The burn patient is best cared for in a dedicated burn center where resuscitation and monitoring concentrate on the pathophysiology of burns, inhalation injury, and edema formation. Early operative intervention and wound closure, metabolic interventions, early enteral nutrition, and intensive glucose control have led to continued improvements in outcome. Prevention of complications such as hypothermia and compartment syndromes is part of burn critical care. The myriad areas where standards and guidelines are currently determined only by expert opinion will become driven by level 1 data only by continued research into the critical care of the burn patient.

Geographic access to burn center hospitals

CONTEXT

The delivery of burn care is a resource-intensive endeavor that requires specialized personnel and equipment. The optimal geographic distribution of burn centers has long been debated; however, the current distribution of centers relative to geographic area and population is unknown.

OBJECTIVE

To estimate the proportion of the US population living within 1 and 2 hours by rotary air transport (helicopter) or ground transport of a burn care facility.

DESIGN AND SETTING

A cross-sectional analysis of geographic access to US burn centers utilizing the 2000 US census, road and speed limit data, the Atlas and Database of Air Medical Services database, and the 2008 American Burn Association Directory.

MAIN OUTCOME MEASURE

The proportion of state, regional, and national population living within 1 and 2 hours by air transport or ground transport of a burn care facility.

RESULTS

In 2008, there were 128 self-reported burn centers in the United States including 51 American Burn Association-verified centers. An estimated 25.1% and 46.3% of the US population live within 1 and 2 hours by ground transport, respectively, of a verified burn center. By air, 53.9% and 79.0% of the population live within 1 and 2 hours, respectively, of a verified center. There was significant regional variation in access to verified burn centers by both ground and rotary air transport. The greatest proportion of the population with access was highest in the northeast region and lowest in the southern United States.

CONCLUSION

Nearly 80% of the US population lives within 2 hours by ground or rotary air transport of a verified burn center; however, there is both state and regional variation in geographic access to these centers.

Resuscitation-induced intestinal edema and related dysfunction: state of the science

High volume resuscitation and damage control surgical methods, while responsible for significantly decreasing morbidity and mortality from traumatic injuries, are associated with pathophysiologic derangements that lead to subsequent end organ edema and dysfunction. Alterations in hydrostatic and oncotic pressures frequently result in intestinal edema and subsequent dysfunction. The purpose of this review is to examine the principles involved in the development of intestinal edema, current and historical models for the study of edema, effects of edema on intestinal function (particularly ileus), molecular mediators governing edema-induced dysfunction, potential role of mechanotransduction , and therapeutic effects of hypertonic saline. We review the current state of the science as it relates to resuscitation induced intestinal edema and resultant dysfunction.

[Importance of abdominal compartment syndrome in Germany: a questionnaire]

BACKGROUND

The abdominal compartment syndrome (ACS) is a life-threatening condition and may affect any critically ill patient. Little is known about the recognition and management of the ACS in Germany.

METHODS

A postal questionnaire was sent to departments of surgery and anesthesia of German hospitals with more than 450 beds.

RESULTS

From the 222 eligible hospitals a total of 113 replies were received. Most respondents (95%) indicated that the ACS plays a role in their clinical practice. Measurement of intra-abdominal pressure (IAP) is not performed by 26% while it is routinely done by 30%. Intra-abdominal pressure is mostly (94%) assessed via the bladder pressure. Of the respondents 41% measure IAP only in those patients thought likely to develop ACS. Risk factors of the ACS would lead to IAP monitoring in 10-23% of cases. The majority (86%) would require signs of organ dysfunction together with exceeding the IAD threshold in order to opt for a surgical decompression. The attitude towards the critical threshold (>20 mmHg or >25 mmhg) divided respondents into two groups of similar size (39% compared to 47%, respectively).

CONCLUSIONS

German anesthesiologists and surgeons are familiar with the ACS. However, about one-quarter never measure IAP and there is a considerable variance as to which patients are at risk to develop ACS and how often IAP should be measured in these patients. This could indicate a lack of acceptance or simply a persisting need for more data concerning the avoidance and treatment of the ACS.

The use of theraputic plasma exchange (TPE) in the setting of refractory burn shock

INTRODUCTION

This study examines the physiologic effects of theraputic plasma exchange (TPE) in the setting of refractory burn shock and attempts to identify variables that correlate with the eventual need for TPE.

METHODS

A retrospective analysis was conducted of 40 patients over 24 months with >20% TBSA burns who experienced complicated resuscitations. TPE was utilized in 21 patients when the patients' total resuscitation volumes exceeded 1.2 times the amount predicted by the modified Baxter formula (3 cm(3) LR/kg/%TBSA). Nineteen matched, contemporaneous patients served as controls. Demographic, injury severity, and acute clinical variables were abstracted for comparison between the two groups. Additionally, the TPE group was analyzed for blood lactate levels, mean arterial pressure (MAP) and urine output (UOP) before and after TPE. Univariate and multivariate statistical analyses were used for comparisons, where appropriate.

RESULTS

In response to TPE, MAP increased by 24% (p<0.0001), UOP increased by >400% (p=<0.0001), IVF rates were reduced by 25% (p=0.01), and lactate levels decreased by almost 50% (p=0.0006). On univariate analysis, admission lactate (p=0.0006) and %TBSA (p=0.01) were found to be significantly increased in the TPE group compared to controls, while there was no difference in age, gender, weight, admission HCT, incidence of acute renal failure, or mortality between the groups. However, on multivariate logistic regression analysis, only elevated admission lactate was independently associated with the eventual need for TPE (OR 2.23, 95% CI=1.30-3.84, p=0.004).

CONCLUSIONS

This is the largest study to date examining TPE as an adjunct in burn resuscitation and suggests that TPE may be effective as a salvage intervention for refractory burn shock. Physiologic parameters clearly improved after the use of TPE without any detected adverse consequences. Also, admission lactate may be a useful indicator to determine who will fail standard burn resuscitation and require TPE.

Fluid resuscitation for major burn patients with the TMMU protocol

BACKGROUND

Fluid resuscitation is one of the critical treatments for the major burn patient in the early phases after injury. We evaluated the practice of fluid resuscitation for severely burned patients with the Third Military Medical University (TMMU) protocol, which is most widely used in many regions of China.

METHODS

Patients with major burns (>30% total body surface area (TBSA)) presenting to Southwest Hospital, Third Military Medical University, between January 2005 and October 2007, were included in this study. Fluid resuscitation was initiated by the TMMU protocol.

RESULTS

A total of 71 patients were (46 adults and 25 children) included in this study. All patients survived the first 48 h after injury smoothly and none developed abdominal compartment syndrome or other recognised complications associated with fluid resuscitation. The average quantity of fluid infused was 3.3-61.33% more than that calculated based on the TMMU protocol in both adult and paediatric groups. The average urine output during the first 24h after injury was about 1.2 ml per kg body weight per hour in the two groups, but reached 1.2 ml and 1.7 ml during the second 24h in adult and pediatric groups, respectively.

CONCLUSION

This study indicates that the TMMU protocol for fluid resuscitation is a feasible option for burn patients. Individualised resuscitation - guided by the physiological response to fluid administration - is still important as in other protocols.

Intra-abdominal hypertension: evolving concepts

This article focuses primarily on the recent literature on abdominal compartment syndrome (ACS) and the definitions and recommendations published by the World Society for the Abdominal Compartment Syndrome. The definitions regarding increased intra-abdominal pressure (IAP) are listed and are followed by an overview of the different mechanisms of organ dysfunction associated with intra-abdominal hypertension (IAH). Measurement techniques for IAP are discussed, as are recommendations for organ function support and options for treatment in patients who have IAH. ACS was first described in surgical patients who had abdominal trauma, bleeding, or infection; but recently, ACS has been described in patients who have other pathologies. This article intends to provide critical care physicians with a clear insight into the current state of knowledge regarding IAH and ACS.

Modern trends in fluid therapy for burns

The majority of burn centres use the crystalloid-based Parkland formula to guide fluid therapy, but patients actually receive far more fluid than the formula predicts. Resuscitation with large volumes of crystalloid has numerous adverse consequences, including worsening of burn oedema, conversion of superficial into deep burns, and compartment syndromes. Resuscitation fluids influence the inflammatory response to burns in different ways and it may be possible, therefore to affect this response using the appropriate fluid, at the appropriate time. Starches are effective volume expanders and early use of newer formulations may limit resuscitation requirements and burn oedema by reducing inflammation and capillary leak. Advanced endpoint monitoring may guide clinicians in when to 'turn off' aggressive fluid therapy and therefore avoid the problems of over-resuscitation.

Management of burn injuries--recent developments in resuscitation, infection control and outcomes research

Introduction

Burn injury and its subsequent multisystem effects are commonly encountered by acute care practitioners. Resuscitation is the major component of initial burn care and must be managed to restore and preserve remote organ function. Later complications of burn injury are dominated by infection. Burn centers are often called to manage soft tissue problems outside thermal injury including soft tissue infection and Toxic Epidermal Necrolysis.

Methods

A selected review of recent reports published by the American Burn Association is provided.

Results

The burn-injured patient is easily and frequently over resuscitated with complications including delayed wound healing and respiratory compromise. A feedback protocol is designed to limit the occurrence of excessive resuscitation has been proposed but no new "gold standard" for resuscitation has replaced the Parkland formula. Significant additional work has been included in recent guidelines identifying specific infectious complications and criteria for these diagnoses in the burn-injured patient. While new medical therapies have been proposed for patients sustaining inhalation injury, a new standard of medical therapy has not emerged. Renal failure as a contributor to adverse outcome in burns has been reinforced by recent data generated in Scandinavia. Of special problems addressed in burn centers, soft tissue infections and Toxic Epidermal Necrolysis have been reviewed but new treatment strategies have not been identified. The value of burn centers in management of burns and other soft tissue problems is supported in several recent reports.

Conclusion

Recent reports emphasize the dangers of over resuscitation in the setting of burn injury. No new medical therapy for inhalation injury exists but new standards for description of burn-related infections have been presented. The value of the burn center in care of soft tissue problems including Toxic Epidermal Necrolysis and soft tissue infections is supported in recent papers.

Abdominal compartment syndrome: pathophysiology and definitions

"Intra-abdominal hypertension", the presence of elevated intra-abdominal pressure, and "abdominal compartment syndrome", the development of pressure-induced organ-dysfunction and failure, have been increasingly recognized over the past decade as causes of significant morbidity and mortality among critically ill surgical and medical patients. Elevated intra-abdominal pressure can cause significant impairment of cardiac, pulmonary, renal, gastrointestinal, hepatic, and central nervous system function. The significant prognostic value of elevated intra-abdominal pressure has prompted many intensive care units to adopt measurement of this physiologic parameter as a routine vital sign in patients at risk. A thorough understanding of the pathophysiologic implications of elevated intra-abdominal pressure is fundamental to 1) recognizing the presence of intra-abdominal hypertension and abdominal compartment syndrome, 2) effectively resuscitating patients afflicted by these potentially life-threatening diseases, and 3) preventing the development of intra-abdominal pressure-induced end-organ dysfunction and failure. The currently accepted consensus definitions surrounding the diagnosis and treatment of intra-abdominal hypertension and abdominal compartment syndrome are presented.

Anesthetic considerations for major burn injury in pediatric patients

Major burn injury remains a significant cause of morbidity and mortality in pediatric patients. With advances in burn care and with the development of experienced multi-disciplinary teams at regionalized burn centers, many children are surviving severe burn injury. As members of the multi-disciplinary care team, anesthesia providers are called upon to care for these critically ill children. These children provide several anesthetic challenges, such as difficult airways, difficult vascular access, fluid and electrolyte imbalances, altered temperature regulation, sepsis, cardiovascular instability, and increased requirements of muscle relaxants and opioids. The anesthesia provider must understand the physiologic derangements that occur with severe burn injury as well as the subsequent anesthetic implications.

Validation of the urine column measurement as an estimation of the intra-abdominal pressure

OBJECTIVE

To evaluate the efficacy of the urine column (UC) measurement compared to the intra-vesicular pressure (IVP) measurement as an estimation of intra-abdominal pressure (IAP) in patients with IAP up to 30 mmHg.

METHODS

Fifteen patients undergoing a laparoscopic cholecystectomy were studied. All patients were catheterized. IVP measurements were performed using a pressure transducer connected to the culture aspiration port. UC measurements were done by holding up the tubing against a measuring rod. The symphysis pubis was used as the zero-reference. IAP was raised from 0 to 30 mmHg using increments of 5 mmHg, during which first the IVP and then UC measurement series were recorded end-expiratory. Fifty and 100 ml of saline were used as a priming volume.

RESULTS

The IVP and UC measurements showed a significant correlation with IAP. Comparing IVP and UC showed a correlation of 0.91 (p < 0.001) for 50 ml and 0.87 (p < 0.001) for 100 ml of saline as a priming volume. Using 50 ml of saline, UC was 0.68 mmHg higher than IVP (95% CI -7.21 to +5.85 mmHg). For 100 ml of saline, UC was 1.23 mmHg lower than IVP (95% CI -7.41 to +9.87 mmHg).

CONCLUSION

UC measurement shows significant correlation to IVP measurement as an estimation of the IAP. Further study needs to be done to conclude whether UC measurement is a reliable clinical alternative to IVP measurement.

Acute kidney injury in burns: a story of volume and inflammation

Acute kidney injury occurs in approximately one-quarter to one-third of patients with major burn injury. Apart from the usual suspects – such as older age, severity of burn injury, sepsis and multiple organ dysfunction – volume overload probably has an important role in the pathogenesis of acute kidney injury.

Burn resuscitation

Current guidelines outlining the resuscitation of severely burned patients, in the United States, were developed over 30 years ago. Unfortunately, clinical burn resuscitation has not advanced significantly since that time despite ongoing research efforts. Many formulas exist and have been developed with the intention of providing appropriate, more precise fluid resuscitation with decreased morbidity as compared to the current standards, such as the Parkland and modified Brooke formulas. The aim of this review was to outline the evolution of burn resuscitation, while closely analyzing current worldwide guidelines, adjuncts to resuscitation, as well as addressing future goals.

Intra-abdominal hypertension: incidence and association with organ dysfunction during early septic shock

PURPOSE

The objective of this article is to study the cumulative incidence of intra-abdominal hypertension (IAH) in septic shock (SS) patients during the first 72 hours of intensive care unit (ICU) admission and to determine if the presence and severity of IAH are associated with sepsis morbidity and mortality.

MATERIALS AND METHODS

Eighty-one consecutive SS patients admitted to a surgical-medical ICU of an academic university hospital (January 2005 to January 2006) were included. Intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) were measured every 6 h (intermittently) for 72 h. Intra-abdominal pressure was registered as minimal, mean, and maximal values per day, during shock and throughout the study period. Intra-abdominal hypertension was diagnosed if IAP remained 12 mm Hg or higher on 2 consecutive measurements and stratified according to the most recent consensus definition (www.wsacs.org).

RESULTS

According to maximal and mean IAP values, 67 (82.7%) and 62 (76.5%) of the patients developed IAH during the study period, respectively. Mean IAP values remained stable throughout the study period. Surgical patients had a higher incidence of IAH than medical patients (93% vs 73%, P < .009). Maximal IAPs were normally distributed, with nonsurvivors exhibiting significantly higher IAP levels during shock (survivors, 17.2 +/- 5.3; nonsurvivors, 19.9 +/- 5.6 mm Hg; P < .04). Patients with IAH exhibited significantly lower values of APP and diuresis, higher values of lactate and creatinine, and higher maximal norepinephrine doses, and were more frequently mechanically ventilated (P < .05 for all). Increasing degrees of IAH and the development of the abdominal compartment syndrome were associated with lower APP and higher maximal serum creatinine levels (P < .03 for both).

CONCLUSIONS

Septic shock patients have a very high incidence of IAH, which seems to be associated with the severity of shock and could be related to the development of organ dysfunctions, particularly renal dysfunction. Intra-abdominal pressure should be routinely monitored during the course of SS.

Secondary abdominal compartment syndrome after severe extremity injury: are early, aggressive fluid resuscitation strategies to blame?

INTRODUCTION

Secondary abdominal compartment syndrome (ACS) is the development of ACS in the absence of abdominal injury. The development of secondary ACS has been viewed by some authors as an unavoidable sequela of the aggressive crystalloid resuscitation often employed in the treatment of severe shock. We hypothesized that poor resuscitation techniques, including early and excessive crystalloid administration, places patients with extremity injuries at risk for developing secondary ACS.

METHODS

The Trauma Registry of the American College of Surgeons database was queried for all patients with an extremity Abbreviated Injury Scale (AIS) score of 3 or greater and abdominal AIS score of 0 treated at our institution between January 1, 2001 and December 31, 2005. The study group included those patients who developed secondary ACS, whereas the comparison cohort included those who did not develop secondary ACS.

RESULTS

Forty-eight patients developed secondary ACS and were compared with 48 randomly selected patients who had an extremity AIS score of 3 or greater and an abdomen AIS score of 0. There were no differences between the groups with respect to age, sex, race, or individual AIS scores. However, the secondary ACS group had a slightly higher Injury Severity Score (25.6 vs. 21.4, p = 0.02), significantly higher operating room crystalloid administration (9.9 L vs. 2.7 L, p < 0.001), and more frequent use of a rapid infuser (12.5% vs. 0.0%, p = 0.01). Multiple logistic regression identified prehospital and emergency department crystalloid as predictors of secondary ACS.

CONCLUSIONS

Aggressive resuscitation techniques, often begun in the prehospital setting, appear to increase the likelihood of patients with severe extremity injuries developing secondary ACS. Early, large volume crystalloid administration was the greatest predictor of secondary ACS.

Intestinal and gastric tonometry during experimental burn shock

INTRODUCTION

The occurrence of organ failure following thermal injury, despite restoration of hemodynamic parameters and urine output during resuscitation, has led to efforts to measure end-organ perfusion. The purpose of this 24-h study was to evaluate the utility of gastrointestinal (GI) tonometry during burn shock and resuscitation.

METHODS

Male swine (n=11, 23.3+/-0.9 kg) were anesthetized with ketamine and propofol. A 70% full thickness burn was caused by immersion in 97 degrees C water for 30 s. Resuscitation with lactated Ringer's, 4 ml/kg/% burn, was begun at hour 6 and titrated to urine output (UO). Arterial blood gases and pulmonary artery catheter data were measured every 6 h. Gastric and ileal regional PCO(2) (PrCO(2)) were measured continuously by air tonometry, and the gastric and ileal intramucosal pH (pHi) and PCO(2) gap (PrCO(2)-PaCO(2)) were calculated every 6 h.

RESULTS

Gastric pHi, ileal PrCO(2), ileal pHi, and ileal PCO(2) gap (but not gastric PrCO(2) or PCO(2) gap) all decreased with shock and were restored to baseline levels by resuscitation. Changes in ileal PrCO(2) were of greater magnitude and demonstrated decreased variability than those in gastric PrCO(2).

CONCLUSIONS

In this model, ileal tonometry outperformed gastric tonometry during burn shock and resuscitation.

The Wittmann Patch s a temporary abdominal closure device after decompressive celiotomy for abdominal compartment syndrome following burn

BACKGROUND

Abdominal compartment syndrome is frequently the result of aggressive fluid resuscitation after burn. Management of the open abdomen following decompressive celiotomy is a major problem.

METHODS

From 2004 to mid-2005, six patients required decompressive celiotomy after developing abdominal compartment syndrome as a result of burn. A Wittmann Patch as used to close the abdominal wound. Patients were re-explored when clinical parameters improved and the abdomen was closed, with long-term follow-up for the abdominal wound.

RESULTS

Of the six patients, five had thermal injury and one had electrical injury. The mean total body surface area affected for thermal burn was 78% and for electrical burn was 37%. Diagnosis of abdominal compartment syndrome was based on elevated bladder pressure and organ dysfunction. The patients were treated with decompressive celiotomy and Wittmann Patch closure. Survivors subsequently underwent primary abdominal closure, with no evidence of ventral hernia at long-term follow-up.

CONCLUSION

In burn cases with abdominal compartment syndrome, a Wittmann Patch ay prove a helpful method of temporary abdominal closure, followed by primary closure with no complications.

The phenomenon of "fluid creep" in acute burn resuscitation

Several reports have documented that modern burn patients receive far more resuscitation fluid than predicted by the Parkland formula-a phenomenon termed "fluid creep." This article reviews the incidence, consequences, and possible etiologies of fluid creep in modern practice and uses this information to propose some therapeutic strategies to reduce or eliminate excessive fluid resuscitation in burn care. A literature review was performed of historical references that form the foundation of modern fluid resuscitation, as well as reports of fluid creep and its consequences. The original Parkland formula required a 24-hour volume of 4 ml/kg/%TBSA lactated Ringer's solution followed by an infusion of 0.3-0.5 ml/kg/ %TBSA plasma. Modern iterations of this formula have omitted the colloid bolus. Numerous exceptions to the formula have been noted, most consistently patients with inhalation injuries. In contrast, recent reports document greatly increased fluid requirements in unselected patients, which seems to consist largely of progressive edema formation in unburned areas, increasing after the first 8 hours post-burn. This has been linked to occurrence of the abdominal compartment syndrome and other serious complications. Strategies to reduce fluid creep include the avoidance of early overresuscitation, use of colloid as a routine component of resuscitation or for "rescue," and adherence to protocols for fluid resuscitation. Fluid creep is a significant problem in modern burn care. Review of original investigations of burn shock, coupled with modern reports of fluid creep, suggests several mechanisms by which this problem can be controlled. Prospective trials of these therapies are needed to confirm their effectiveness.