Abdominal compartment syndrome

Use of power Doppler ultrasound to monitor renal perfusion during burn shock

BACKGROUND

Renal cortical blood flow can be quantified by means of power Doppler ultrasound (PDUS) image analysis. We hypothesized that renal cortical perfusion, estimated by PDUS image intensity (PDUSII), would decrease during burn shock and improve during resuscitation in a porcine model.

METHODS

Eight anesthetized swine sustained a 75% scald injury. Resuscitation began 6h postburn. Renal cortical blood flow was measured directly using fluorescent microspheres (CORFLO), and was estimated noninvasively by PDUSII. PDUSII, CORFLO, and cardiopulmonary data were recorded every 2h.

RESULTS

PDUSII decreased significantly from preburn to postburn hour 6, and increased with resuscitation by hour 8. CORFLO correlated well with PDUS image intensity (n=48, r(2)=0.696) but poorly with urine output (n=48, r(2)=0.252).

CONCLUSION

PDUS in this study was superior to the urine output in assessing renal cortical microvascular blood flow during shock and resuscitation, and may be useful in the care of injured patients.

Abdominal hypertension and liver dysfunction in intensive care unit patients: an "on-off" phenomenon?

Intra-abdominal hypertension (IAH) can affect liver hemodynamics but it is not known if has a significant clinical impact on liver function. The aim of this study was to investigate the relationship between IAH and liver function. A prospective study was performed in 110 adult intensive care unit (ICU) patients. Intra-abdominal pressure (IAP) was measured on admission and every other day, and liver sequential organ failure assessment (SOFA) score was collected whenever IAP was measured. IAH was defined by a IAP >or= 10 mm Hg, and liver dysfunction was defined by a hepatic SOFA score >or= 2. An overall IAH incidence of 56.3% was found (n = 62). Thirty-three patients presented a liver SOFA score >or= 2, with an overall incidence of 30%. Liver SOFA score of the group of patients with abdominal hypertension was higher than in group of patients without abdominal hypertension. (0.8 +/- 1.05 vs 0.4 +/- 0.7; P < .05), but IAH and liver dysfunction were not significantly associated (chi2 = 2.03; P = .15). When the whole sample was divided according to the worst IAP score (IAP < 10, IAP between 10 and 15, and IAP > 15), the corresponding liver dysfunction scores in the three groups were 0.35 +/- 0.6, 0.74 +/- 1, and 1.2 +/- 1.3, respectively (P = .01). A strict association between IAH and liver dysfunction was not found. Most likely, low levels of IAH, although able to reduce liver blood flow, are not per se sufficient to produce a real dysfunction; however, a correlation between the degree of IAH and the degree of hyperbilirubinemia exists. IAH does not seem to be an "on-off" phenomenon, but produces liver alterations for increasing levels of its severity.

Comportamento da pressão intracraniana, da perfusão cerebral e dos parâmetros hemodinâmicos durante a síndrome do compartimento abdominal em cães

OBJETIVO: Estudar as alterações hemodinâmicas e as repercussões sobre o sistema nervoso central ocasionados pela síndrome do compartimento abdominal. MÉTODO: Utilizou-se cães sem raça definida submetidos à anestesia geral e monitorização das pressões arterial média(PAM), intracraniana(PIC), de perfusão cerebral(PPC), da artéria pulmonar(PAP) e venosa central(PVC), do débito cardíaco(DC) e da freqüência cardíaca(FC). Aumentou-se a pressão intra-abdominal(PIA) para níveis de 10,20,30 e 40cmH2O . Após atingir-se nível PIA=40cmH2O realizou-se a descompressão cirúrgica da cavidade abdominal. Em cada etapa realizou-se a medida dos parâmetros PIA, PIC, PAM, PPC, PVC e DC. RESULTADOS: Observou-se que o aumento da PIA causou as seguintes alterações fisiológicas: aumento progressivo da PIC; aumento da PAM até PIA=20cmH2O e diminuição progressiva da mesma após PIA= 40cmH2O; aumento da PPC até PIA=10cmH2O e diminuição progressiva da mesma após PIA= 30cmH2O; aumento progressivo da PVC; diminuição progressiva do DC após PIA= 30cmH2O; Após a descompressão da cavidade, notou-se o retorno da PIC, PAM, PPC, PVC e do DC para valores próximos aos dos iniciais (antes do aumento da PIA). CONCLUSÕES: Concluímos que o aumento da PIA provocou alterações nos sistemas cardiovascular e nervoso central, que foram revertidas após a descompressão cirúrgica da cavidade abdominal.

Open abdomen management after massive bowel resection for superior mesenteric arterial occlusion

PURPOSE

Massive bowel resection is often performed for superior mesenteric arterial (SMA) occlusion, resulting in short bowel syndrome. We conducted this study to evaluate the effectiveness of open abdomen management to monitor the blood flow of the remnant bowel and anastomoses.

METHODS

We treated five of seven patients with SMA occlusion by open abdomen management, with or without mesh, using a zipper, which we opened daily to monitor the blood flow around the anastomotic site.

RESULTS

None of the five patients treated by open abdomen management required re-resection of the remnant bowel and they were all discharged from hospital in a stable condition.

CONCLUSION

Open abdomen management proved extremely useful for monitoring blood flow to the anastomotic site and for allowing complete drainage into the abdominal space. Using this method would assist in leaving as much remnant bowel as possible after resection for SMA occlusion.

Significance of Early Diagnosis of Abdominal Compartment Syndrome in Major Burns

Four cases of abdominal compartment syndrome in patients suffering major burns, who were treated at Hamilton General Hospital, Hamilton, Ontario, from January 1998 to June 2003, are reported. The pathophysiological changes, and the high morbidity and mortality associated with this condition are also described. The significance of early diagnosis of this syndrome is discussed. The literature is reviewed and a protocol is suggested for measuring urinary bladder pressure when managing major burns.

Adverse Effects of Increased Intra-abdominal Pressure on Small Bowel Structure and Bacterial Translocation in the Rat

BACKGROUND

The purpose of this study was to evaluate the effects of elevated intra-abdominal pressure (IAP) on intestinal structures and bacterial translocation in the rat.

MATERIALS AND METHODS

Forty-two male Sprague-Dawley rats were randomly divided into three experimental groups of 14 rats each: the sham group underwent insertion of a balloon-tipped catheter; the IAP-15 group was subjected to a 15 mm Hg pneumoperitoneum for 60 minutes; and the IAP-25 group was subjected to a 25 mm Hg pneumoperitoneum for 60 minutes. Intestinal structural changes (bowel circumference, overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) and bacterial translocation to mesenteric lymph nodes, liver, spleen, portal blood, and peripheral blood were determined 24 hours following pneumoperitoneum.

RESULTS

IAP-15 and IAP-25 rats demonstrated a significant decrease in: bowel and mucosal weight in the duodenum, jejunum, and ileum; mucosal DNA and protein in the jejunum and ileum; villus height in the jejunum: and crypt depth in the jejunum and ileum compared to the sham rats. Bacterial translocation was demonstrated in 60% of IAP-15 rats and in 80% of IAP-25 rats.

CONCLUSION

Elevated IAP results in mucosal injury of the gut, causing mucosal hypoplasia, and increases bacterial translocation.

Damage Control Surgery for Abdominal Trauma

Damage control is not a modern concept, but the application of this approach represents a new paradigm in surgery, borne out of a need to save patients with severe exsanguinating injuries. Definitive control and repair may be accomplished in the immediate post injury setting but the physiological derangement due to massive shock state resulting from the severe injury and the resuscitation that follows, often leads to a fully repaired but dead patient. The vicious triad of death in trauma, namely hypothermia, acidosis and coagulopathy should be tackled by initial abbreviated laparotomy, correction of physiological derangements and finally definitive repair of all injuries at second laparotomy. The concept needs a dedicated team effort with careful patient selection for achieving the optimal results.

Effects of Pneumoperitoneum and LPS-induced Endotoxemia on Cerebral Perfusion Pressure in Pigs

Multitrauma patients commonly develop abdominal compartment syndrome, which is defined as the end result of sustained, uncorrected, intra-abdominal hypertension. We aimed to assess the effects of increased intra-abdominal pressure (IAP) upon intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in the presence or absence of lipopolysacharide (LPS)-induced endotoxemia using an experimental porcine model of pneumoperitoneum. Experimental procedures were approved by the Animal Care Review Committee of the National Veterinary Institute. Sixteen female pigs weighing 20 to 25 kg, aged 3 to 4 months were used. The animal model of increased IAP employed in our studies was produced with intraperitoneal administration of helium at 25 mm Hg under general anesthesia. After induction of pneumoperitoneum, 16 animals were randomly divided into 2 groups of 8 pigs each. One group received LPS intravenously (endotoxin group) and the second group received saline (control group). ICP, CPP, and hemodynamic variables were continuously monitored and recorded. A significant reduction of the cardiac output and concurrent increases in systemic vascular resistance and central venous pressure were observed in both groups after induction of pneumoperitoneum. ICP increased whereas CPP decreased significantly compared with baseline values in both groups after elevation of IAP. After LPS administration (endotoxin group), the cardiac output and mean arterial pressure decreased significantly. The CPP decreased further in the endotoxin group after LPS administration, whereas ICP remained unchanged. IAP increases produce significant increases in the ICP and decreases in the CPP in this animal model. LPS-induced endotoxemia further decreased CPP.

Early definitive abdominal closure using serial closure technique on injured soldiers returning from Afghanistan and Iraq

BACKGROUND

Twenty-nine of 1,284 battle-injured soldiers arriving at Walter Reed Army Medical Center from Operations Enduring Freedom and Iraqi Freedom have abdominal wounds requiring delayed definitive closure with Gore-Tex (WL Gore & Assoc) mesh.

METHODS

Serial abdominal closure (SAC) leading to early definitive abdominal closure (EDAC) was achieved using Gore-Tex mesh. Inpatient records of Operations Enduring Freedom and Iraqi Freedom soldiers with open or reopened abdomens were reviewed from March 2003 to August 2005.

RESULTS

Twenty-nine soldiers, average age 27 years (range 20 to 42 years) injured by secondary blast effects (n = 19); penetrating (n = 8); motor vehicle crashes (n = 1); and crushing injury (n = 1) were included in the study. Patients arrived at Walter Reed Army Medical Center 8 days (range 3 to 56 days) after injury with Gore-Tex mesh placed 6 days (range 0 to 26 days) from arrival and 14 days (range 4 to 79 days) from injury. SAC was achieved with towel clamp tightening or excision of midline mesh and drawing fascia closer to the midline for an average of 46 days (range 15 to 160 days) before EDAC. One patient is undergoing SAC and another was transferred to another facility. EDAC was achieved in 24 of the remaining of 27 patients (89%). Four patients required early removal of the Gore-Tex mesh, resulting in three patients with planned ventral hernia. One patient underwent EDAC with primary closure and fascial release. EDAC was completed with polypropylene mesh in 17 patients and 6 patients had original Gore-Tex in place. Patients were discharged from the hospital an average of 18 days after closure (range 1 to 89 days) with total hospital days of 62 (range 17 to 197 days). Average followup of patients from placement of Gore-Tex mesh is 264 days (range 31 to 855 days).

CONCLUSIONS

SAC with Gore-Tex mesh led to EDAC in 89% of patients and proved to be a safe and effective alternative to planned ventral hernia. SAC allowed protection of abdominal contents, effective fluid management, reclamation of abdominal domain, and early rehabilitation with minimal complications and only one hernia reoccurrence.

Role of endothelin-1 and cyclic nucleotides in ischemia/reperfusion-mediated microvascular leak

BACKGROUND

A consequence of ischemia/reperfusion (IR) is endothelial barrier dysfunction and intravascular volume loss. The purposes of our study are to explore the impact of: 1) cyclic guanosine monophosphate (cGMP) synthesis inhibition, 2) cyclic adenosine monophosphate (cAMP) synthesis inhibition, 3) treatment with endothelin-1, and 4) endothelin-1 (ET-1)-mediated cAMP changes on IR-induced fluid leak. We hypothesize that IR-mediated microvascular fluid leak results from increased cGMP activity and ET-1 decreases IR-induced fluid leak via cAMP.

METHODS

A micro-cannulation technique was used to determine fluid leak or hydraulic permeability (Lp) in rat mesenteric venules. Lp was measured during IR and after treatment with 1) cGMP synthesis inhibitor (LY83583,10 micromol/L) 2) cAMP synthesis inhibitor (2',5'dideoxyadenosine,10 micromol/L), 3) ET-1 (80 pM), and 4) cAMP synthesis inhibitor plus ET-1 (n=6 in each group; Lp represented as mean+/-standard error of the mean; units 10-cm/sec/cmH2O).

RESULTS

IR resulted in an increase in Lp (Lp=7.07+/-0.20) sevenfold above baseline (1.05+/-0.31) (p<or=0.001). Compared with IR alone, 1) pretreatment with cGMP synthesis inhibitor completely blocked IR-induced fluid leak (Lp=1.08+/-0.18) (p<or=0.001), 2) pretreatment with cAMP synthesis inhibitor attenuated fluid leak (Lp=3.92+/-0.20) (p<or=0.005), 3) treatment with ET-1 decreased fluid leak (Lp=5.38+/-0.28) (p<or=0.005), and 4) pretreatment with a cAMP inhibitor plus treatment with ET-1 reduced fluid leak nearly 50% compared with ET-1 alone (Lp=2.95+/-0.12) (p<or=0.005).

CONCLUSION

cGMP inhibition completely blocks fluid leak, pointing toward a central role as a mediator of IR-induced postcapillary venular leak. ET-1 mildly decreased leak. Furthermore, ET-1 may not exert its effects on microvascular fluid leak during IR via cAMP.

Hypertonic lactated saline resuscitation reduces the risk of abdominal compartment syndrome in severely burned patients

BACKGROUND

Secondary abdominal compartment syndrome is a lethal complication after resuscitation from burn shock. Hypertonic lactated saline (HLS) infusion reduces early fluid requirements in burn shock, but the effects of HLS on intraabdominal pressure have not been clarified.

METHODS

Patients admitted to our burn unit between 2002 and 2004 with burns > or =40% of the total body surface area without severe inhalation injury were entered into a fluid resuscitation protocol using HLS (n = 14) or lactated Ringer's solution (n = 22). Urine output was monitored hourly with a goal of 0.5 to 1.0 mL/kg per hour. Hemodynamic parameters, blood gas analysis, intrabladder pressure as an indicator of intraabdominal pressure (IAP), and the peak inspiratory pressure were recorded. Pulmonary compliance and the abdominal perfusion pressure were also calculated.

RESULTS

In the HLS group, the amount of intravenous fluid volume needed to maintain adequate urine output was less at 3.1 +/- 0.9 versus 5.2 +/- 1.2 mL/24 h per kg per percentage of total body surface area, and the peak IAP and peak inspiratory pressure at 24 hours after injury were significantly lower than those in the lactated Ringer's group. Two of 14 patients (14%) in the HLS group and 11 of 22 patients (50%) developed IAH within 20.8 +/- 7.2 hours after injury.

CONCLUSION

In patients with severe burn injury, a large intravenous fluid volume decreases abdominal perfusion during the resuscitative period because of increased IAP. Our data suggest that HLS resuscitation could reduce the risk of secondary abdominal compartment syndrome with lower fluid load in burn shock patients.

The effect of blunt abdominal trauma on appendix vermiformis

OBJECTIVES

Trauma and appendicitis are the most common conditions of childhood for which surgical consultation is sought in emergency departments. Occasionally, appendicitis and trauma exist together, which causes an interesting debate whether trauma has led to appendicitis. We aimed to evaluate our patients with traumatic appendicitis and to discuss their properties in the light of the literature.

METHODS

We retrospectively reviewed the charts of children of blunt abdominal trauma accompanied by appendicitis.

RESULTS

Of 29 cases of blunt abdominal trauma that had required surgical exploration, five were found to have gross findings of acute appendicitis and underwent appendicectomy. Appendicitis was confirmed histopathologically.

CONCLUSION

It should be kept in mind that children managed for severe blunt abdominal trauma may develop appendicitis. If clinical outlook suggests appendicitis in cases conservatively managed for blunt abdominal trauma, physical examinations, abdominal ultrasonography and/or abdominal computed tomography should be repeated for diagnosis of traumatic appendicitis. This approach will help to protect the patients against the complications of appendicitis that are likely to develop.

Abdominal compartment syndrome contributing to failure of extracorporeal membrane oxygenation in an infant with congenital heart disease and sepsis

OBJECTIVE

To provide the first account of extracorporeal membrane oxygenation therapy failure secondary to abdominal compartment syndrome.

DESIGN

Case report.

SETTING

Pediatric intensive care unit.

PATIENT

A 4-month-old infant with cyanotic congenital heart disease and Escherichia coli sepsis developed abdominal distention and venous return failure on extracorporeal membrane oxygenation.

INTERVENTION

Emergency cardiac catheterization and atrial septectomy were performed.

MAIN RESULTS

Central venous pressure of 120 mm Hg was measured, confirming the diagnosis of abdominal compartment syndrome.

CONCLUSIONS

Abdominal compartment syndrome is a life-threatening condition resulting from an increase in intra-abdominal pressure that compromises abdominal organ perfusion, pulmonary function, and cardiac output. Mortality rates from abdominal compartment syndrome are as high as 60% in adults and children. This report of an infant with congenital heart disease and E. coli sepsis represents the first description of abdominal compartment syndrome that contributed to failure of extracorporeal membrane oxygenation and ultimately death. The pathophysiology, diagnosis, and treatment of abdominal compartment syndrome are also reviewed.

Secondary Abdominal Compartment Syndrome in Children With Burns and Trauma: A Potentially Lethal Complication

Acute, rapid, and unimpeded increases in intra-abdominal pressure can lead to multiple organ dysfunction defined as the abdominal compartment syndrome (ACS). If this develops in the absence of obvious intra-abdominal injury, it has been termed secondary ACS (2 degrees ACS). Massive fluid resuscitation in the presence of large burns or shock can lead to 2 degrees ACS. The importance of early recognition and the need for urgent abdominal decompression have been recognized in adults; however, this has not been appreciated in the pediatric population. Medical records of four children diagnosed with 2 degrees ACS were reviewed. Secondary ACS occurred in three children with burns and in one child with a traumatic brain injury. Three children underwent decompressive laparotomy, and one underwent successful percutaneous drainage. There were two survivors. Secondary ACS may be observed in burnt or traumatized children needing large volume resuscitation. Early recognition of 2 degrees ACS by routine bladder pressure monitoring in this high-risk group of children may result in earlier decompression and a possible decrease in morbidity and mortality.

Complications after 344 damage-control open celiotomies

BACKGROUND

We reviewed our experience with the open abdomen and hypothesized that the known high wound complication rates were related to the timing and method of wound closure.

METHODS

All trauma admissions from 1995 through 2002 requiring an open abdomen and temporary abdominal coverage were included. The study group was then classified by three wound closure methods used in survivors: 1) primary (primary fascial closure); 2) temporizing (skin only, spit thickness skin graft and/or absorbable mesh), and 3) prosthetic (fascial repair using nonabsorbable prosthetic mesh).

RESULTS

In all, 344 patients required an open abdomen and temporary abdominal coverage either as part of a planned staged damage-control celiotomy (66%) or the development of the abdominal compartment syndrome (33%). Of these, 276 patients survived to wound closure. Sixty-nine of the 276 (25%) suffered wound complications (wound infection, abscess, and/or fistula). Thirty-four (12%) died after wound closure; seven of the deaths as a direct result of the wound complication. Complications increased significantly after 8 days (p < 0.0001) from the initial operative intervention to fascial closure. Primary fascial closure was achieved in 180 of 276 (65%) patients. Although there was no difference in the mean Injury Severity Score between the three groups, the primary group had significantly fewer mean transfusion requirements, shorter mean time to fascial closure, and a lower complication rate as compared with either the temporizing or prosthetic groups. The primary group thus incurred significantly less mean initial hospitalization charges.

CONCLUSION

Morbidity associated with wound complications from the open abdomen remains high (25%). Morbidity is associated with the timing and method of wound closure and transfusion volume, but independent on injury severity. Also, delayed primary fascial closure before 8 days is associated with the best outcomes with the least charges.

The ???Fistula VAC,??? a Technique for Management of Enterocutaneous Fistulae Arising within the Open Abdomen: Report of 5 Cases

BACKGROUND

Management of intestinal fistulae in open abdominal wounds remains a significant clinical challenge for those caring for patients surviving damage control abdominal operations. Breaking the cycle of tissue inflammation, infection, and sepsis, resulting from leakage of enteric contents, should be a major goal in the approach to these complex patients. We describe a technique utilizing vacuum assisted closure (VAC) which achieves control of enteric flow from fistulae in open abdominal wounds.

METHODS

The fistula-VAC is fashioned from standard sponge supplies, negative pressure pumps, and ostomy appliances. The fistula-VAC was changed every three days prior to split thickness skin grafting, and every five days following grafting.

RESULTS

Five patients underwent application of the fistula-VAC. All patients had complete diversion of enteric contents. This enteric diversion allowed for successful skin grafting in all patients.

CONCLUSION

Application of the fistula-VAC should be considered a useful option in treating patients with intestinal fistulae in open abdominal wounds.

Avaliação da função respiratória em indivíduos submetidos à abdominoplastia

OBJETIVO: Avaliar a função respiratória em indivíduos submetidos à abdominoplastia, através de parâmetros espirométricos. MÉTODO: Estudo prospectivo de 33 mulheres hígidas e não tabagistas, submetidas à abdominoplastia, e com resultados normais para as radiografias de tórax realizadas antes e quatro dias após a operação. Foram realizadas provas espirométricas no pré-operatório, no quarto, 15o e no 30o dias de pós-operatório. RESULTADOS: Provas espirométricas evidenciaram que, exceto pela relação VFE1/CVF e FEF 25-75%/CVF, todos os demais parâmetros avaliados (CVF, VEF1, FEF 25-75% e PFE) se apresentaram significativamente diminuídos no 4o PO em relação aos valores pré-operatórios. Os valores de CVF e PFE se mostraram normalizados à avaliação realizada no 30o PO. Já os valores de VEF1 ainda se revelaram significativamente inferiores aos valores pré-operatórios mesmo na última avaliação. CONCLUSÕES: Ocorreu diminuição da função respiratória no 4º dia de pós-operatório com normalização até o 30º dia de pós-operatório.

Hyperacute abdominal compartment syndrome: an unrecognized complication of massive intraoperative resuscitation for extra-abdominal injuries

Primary and secondary abdominal compartment syndrome (ACS) are well-recognized entities after trauma. The current study describes a "hyperacute" form of secondary ACS (HACS) that develops intraoperatively while repair of extra-abdominal injuries is being carried out simultaneous with massive resuscitation for shock caused by those injuries. The charts of patients requiring abdominal decompression (AD) for HACS at time of extra-abdominal surgery at our level I trauma center were reviewed. The following data was gathered: age, Injury Severity Score (ISS), mechanism, resuscitation details, time to AD, time to abdominal closure, and outcome. All continuous data are presented as mean +/- standard error of mean. Hemodynamic and ventilatory data pre- and post-AD was compared using paired t test with significance set at P < 0.05. Five (0.13%) of 3,750 trauma admissions developed HACS during the 15-month study period ending February 2004. Mean age was 32 +/- 7 years, and mean ISS was 19 +/- 2. Four of five patients arrived in hemorrhagic shock (blunt subclavian artery injury, 1; chest gunshot, 1; gunshot to brachial artery, 1; stab transection of femoral vessels, 1) and were immediately operated upon. One of five patients (70% burn) developed HACS during burn wound excision on day 2. HACS developed after massive crystalloid (15 +/- 1.7 L) and blood (11 +/- 0.4 units) resuscitation during prolonged surgery (4.8 +/- 0.8 hours). Pre- versus post-AD comparisons revealed significant (P < 0.05) improvements in mean arterial pressure (55 +/- 6 vs 88 +/- 3 mm Hg), peak airway pressure (44 +/- 5 vs 31 +/- 2 mm Hg), tidal volume (432 +/- 96 vs 758 +/- 93 mL), arterial pH (7.16 +/- 0.0 vs 7.26 +/- 0.04), and PaCO2 (52 +/- 6 vs 45 +/- 6 mm Hg). There was no mortality among the group, and all patients underwent abdominal closure by fascial reapproximation in 2-5 days. Two (40%) of the five patients required extremity fasciotomy for compartment syndrome. HACS is a rare complication of massive resuscitation for extra-abdominal injuries. It should be considered in such patients in the face of unexplained hemodynamic and/or ventilatory decompensation. Prompt AD is life saving. Early abdominal closure is usually possible. Vigilance for compartment syndromes elsewhere in the body is warranted in any patient with HACS.)

Increased intra-abdominal pressure: is it of any consequence in severe acute pancreatitis?

BACKGROUND

Increased intra-abdominal pressure (IAP) is detrimental for the recovery of organ function in trauma and emergency patients. The aim of this study was to assess the correlation between the dynamics of IAP and organ dysfunction in severe acute pancreatitis (SAP).

MATERIALS AND METHODS

Management of SAP between 2000 and 2004 was analysed. SAP was classified according to Atlanta 1992. Organ dysfunction, systemic inflammatory response syndrome (SIRS) and outcomes in relation to the IAP were assessed. IAP was measured indirectly.

RESULTS

A total of 65 patients, with an average APACHE II score of 6.44, complied with the Atlanta criteria. In all, 34 patients received conservative treatment and 31 were operated. SIRS was observed in 59 cases and multiple organ dysfunction syndrome (MODS) in 61 cases. IAP was significantly higher in the 25 most complicated patients requiring renal replacement therapy (RRT), compared with 40 patients without RRT, 31.72 vs 21.4 cm/H(2)O (p=0.037). IAP interrelated positively with SOFA score (r = + 0.371, p<0.01) and organs involved (r = + 0.356, p<0.01), and negatively with platelet count and enterally provided volume (r = - 0.284, p<0.01; r = - 0.5, p<0.01, respectively). Overall mortality (9.2%) was associated with surgery and sustained increase of the IAP over 25 cm/H(2)O. Our data support the pathophysiological interrelation of elevated IAP and development of organ dysfunction.

CONCLUSION

Development of organ dysfunction in SAP could be associated with increased IAP. Grade III increase of IAP should be considered as an indicator for revision of treatment modalities.

Early Aggressive Closure of the Open Abdomen

BACKGROUND

The aim of this series is to describe a new and aggressive approach to definitive closure of the open abdomen.

METHODS

A retrospective review of 37 patients who underwent definitive abdominal closure using a combination of vacuum pack, vacuum-assisted wound management and human acellular dermal matrix (HADM).

RESULTS

All patients' open abdomens were maintained with vacuum assisted wound management in attempts for primary closure. Once it was determined that the abdomen would not close primarily; it was closed with HADM and skin advancement. The mean duration of the open abdomen was 21.7 days (range 6-45), with an average of 127.78 cm of HADM, the largest number being 800 cm, with decreasing use of product later in the series. No major complications were seen with the repair. Superficial wound infection occurred with two patients that were easily treated with wet to dry dressing changes. No intraabdominal complications such as fistula or graft loss were seen. All patients left the hospital with an intact abdominal wall and skin. All 37 patients survived to discharge and were seen in follow-up within one month. No early hernia formation was seen at the one month follow up with the longest at three years. No abdominal wall complications were seen in subsequent follow up patients.

CONCLUSIONS

Early aggressive closure of the open abdomen is possible with a combination of vacuum pack, vacuum-assisted wound management and HADM. Short term results are promising and warrant further study.

Management of intra-abdominal hypertension in patients with severe acute pancreatitis with continuous hemodiafiltration using a polymethyl methacrylate membrane hemofilter

To evaluate, with a prospective observational study, whether continuous hemodiafiltration using a polymethyl methacrylate membrane hemofilter (PMMA-CHDF) is effective for prevention and treatment of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) on patients with severe acute pancreatitis (SAP). The study was carried out in the general intensive care unit (ICU) of a university hospital. Seventeen consecutive patients with SAP were treated in the intensive care unit and underwent PMMA-CHDF whether or not they had renal failure. Blood level of interleukin (IL)-6, as an indicator of cytokine network activation, and intra-abdominal pressure (IAP) were measured daily to investigate their time-course of changes and the correlation between the two. The blood level of IL-6 was high at 1350+/-1540 pg/mL on admission to the ICU. However, it significantly decreased to 679+/-594 pg/mL 24 h after initiation of PMMA-CHDF (P<0.05), and thereafter decreased rapidly. Mean intra-abdominal pressure (IAP) on admission was high, at 14.6+/-5.3 mm Hg, with an IAP of 20 mm Hg or over in 2 of 17 patients, showing that they had already developed IAH. The IAP was significantly lower (P<0.05) 24 h after initiation of PMMA-CHDF, and subsequently decreased. There was a significant positive correlation between blood level of IL-6 and IAP, suggesting that PMMA-CHDF improved vascular permeability through elimination of cytokines, and that it thereby decreased interstitial edema to lower IAP. Sixteen of the 17 patients were discharged from the hospital in remission from SAP without development of complications. Continuous hemodiafiltration using a polymethyl methacrylate membrane hemofilter appears to be effective for prevention and treatment of IAH in patients with SAP through the removal of causative cytokines of hyperpermeability.

Management of Intraabdominal Hypertension by Percutaneous Catheter Drainage

The authors report a case of an 18-year-old man with T-cell acute lymphocytic leukemia who developed hemorrhagic pancreatitis after chemotherapy. He subsequently developed abdominal compartment syndrome (ACS). Computed tomography showed a large fluid-filled mass in the area of the pancreas. As a result of the instability of his condition, surgical decompression, the standard therapy for ACS, was believed to carry significant morbidity and potential mortality. The patient underwent ultrasound-guided drainage of the peripancreatic fluid, which decreased his abdominal pressures and improved his clinical status. Without this procedure, the patient may not have tolerated subsequent surgery.

Increased intra-abdominal pressure causes bacterial translocation in rabbits

BACKGROUND

Abdominal compartment syndrome (ACS) is defined as intra-abdominal hypertension associated with organ dysfunction. Subsequently, increased intra-abdominal pressure (IAP) adversely affects the pulmonary, cardiovascular, renal, musculoskeletal/integumentary and central nervous systems. Bacterial translocation (BT), which is defined as the movement of viable enteric bacteria to the mesenteric lymph nodes, liver and spleen, occurs after various types of stress and results in splanchnic ischemia. In this experimental study, we aimed to investigate the effects of various levels of increased IAP on BT in rabbits; IAP was increased by the intra-abdominal balloon-insufflation method, thus simulating noncompliant abdominal-wall closure under tension.

METHODS

Fifty rabbits were randomly assigned to 1 of 5 groups, with each group comprising 10 animals. In group I (control group), an intra-abdominal balloon was placed without inflation. In groups II, III, IV and V, IAPs of 10, 15, 20 and 25 mmHg, respectively, were established via inflation of the intra-abdominal balloon. All groups underwent laparotomy after 12 hours. Multiple biopsies were taken from ileocecal lymph nodes, the spleen and liver.

RESULTS

BT was observed to some degree in all 4 experimental groups. A gradual increase in the phenomenon was noted as IAP increased from 10 to 15 mmHg; and BT was overt at 20 mmHg, and significant at 25 mmHg. Klebsiella pneumoniae, Serratia marcescens, and Escherichia coil were the predominant pathogens identified by culture.

CONCLUSION

We propose that an intravesical pressure (IVP) of 15 mmHg is the critical point for BT in patients with increased IAP. In this experimental study, BT occurred when IVP reached 20 mmHg. We suggest that IVP monitoring is desirable in the management of patients with ACS, and that decompressive laparotomy should be performed in patients with IVP >20 mmHg.

Pressão intra-abdominal em pacientes com trauma abdominal

OBJETIVOS: Pacientes com trauma abdominal tratados cirurgicamente são muito suscetíveis ao desenvolvimento de hipertensão intra-abdominal e síndrome do compartimento abdominal, cujo diagnóstico é baseado na medição da pressão intraabdominal associada a parâmetros clínicos. Este estudo teve por objetivos avaliar prospectivamente o comportamento da pressão intra-abdominal de pacientes com trauma abdominal cirurgicamente tratados e identificar se há relação entre tal comportamento e parâmetros clínicos destes pacientes. MÉTODO: A técnica de Kron foi utilizada para medir a pressão intra-abdominal. A casuística foi composta por 17 homens e três mulheres com média de idade de 36,9 anos (D.P. 12,943). O mecanismo de trauma mais freqüente foi contusão abdominal 12 (60%) contra oito (40%) pacientes com ferimentos penetrantes. Os dados foram coletados em 6 e 18 horas de pós-operatório. RESULTADOS: As médias de pressão intra-abdominal foram 10,4 cmH2O (D.P. 3,939) em 6 horas e 10,263 cmH2O (D.P. 3,445) em 18 horas de pós operatório. A análise dos resultados mostrou correlação estatisticamente significante entre o volume de colóides infundidos e a pressão intra-abdominal em 6 e 18 horas pós-operatórias (p = 0,0380 e p = 0,0033 respectivamente). É provável que tal correlação se deva ao edema visceral causado pelo extravasamento capilar de soluções, aumentando a pressão intra-abdominal. CONCLUSÕES: Os achados deste estudo ratificam a idéia de relação entre grandes volumes de infusão venosa, sobretudo colóides, e o aumento da pressão intra-abdominal e destacam a importância da avaliação da pressão intra-abdominal em pacientes com trauma abdominal submetidos a grandes reposições volêmicas, sobretudo as soluções coloidais.

Decompressive laparotomy to treat intractable intracranial hypertension after traumatic brain injury

INTRODUCTION

Increases in intra-abdominal pressure (IAP) can cause increases in intracranial pressure (ICP). Recently, we noticed that abdominal fascial release could be useful in treating intracranial hypertension (ICH) after traumatic brain injury (TBI). We added this as an option in our treatment of TBI.

METHODS

In our institution, ICH is treated with an algorithm using osmolar therapy, CSF drainage and barbiturates. Patients with refractory ICH have routine measurement of IAP. If elevated, consideration is given to decompressive laparotomy. We retrospectively reviewed all patients admitted from January 2000 through July 2003 who had abdominal decompression to treat refractory ICH.

RESULTS

From 1/00 to 7/03, 17 patients underwent decompressive laparotomy for intractable ICH. Thirteen male and 4 females all sustained blunt injury. All had failed maximal therapy including 14 who had had decompressive craniectomy. Mean ICP was 30 +/- 8.1 mmHg (range 20-40 mmHg) before decompression. No patients had evidence of abdominal compartment syndrome (ACS). Before decompression mean IAP was 27.5 (+/- 5.2) mmHg (range 21-35 mmHg). After abdominal decompression ICP dropped precipitously by at least 10 mmHg to a mean of 17.5 (+/- 3.2) mmHg (range 10-25 mmHg). In 6 patients the decrease in ICP was transient. All died. The remaining 11 had sustained decreases in ICP. All survived, made neurologic recovery and were discharged to a rehabilitation facility.

CONCLUSION

Decompressive laparotomy can be a useful adjunct in the treatment of ICH failing maximal therapy following TBI. More work will need to be done to precise the exact indications for this therapy.

Measurement of intra-abdominal pressure in intensive care units in the United Kingdom: a national postal questionnaire study

BACKGROUND

To explore the attitudes of intensivists in the UK to intra-abdominal pressure (IAP) measurement and abdominal compartment syndrome (ACS) and to determine current practice.

METHODS

A postal questionnaire study addressed to the lead clinician in the intensive care unit was sent to hospitals in the UK with a general surgical service.

RESULTS

Completed questionnaires were received from 137 of the 207 hospitals surveyed (66.2% response rate). Only 1.5% of the respondents (n=2) had no prior knowledge of intra-abdominal hypertension and ACS. IAP had been measured on some occasion by 75.9% (n=104) of the respondents, always by the intravesical route. Among those intensive care units that measured IAP, in 93.2% (n=97) it was only measured when there was a suspicion of the development of ACS; 3.8% of units (n=4) measured IAP on all patients who had undergone an emergency laparotomy, and 2.9% (n=3) measured IAP only in those who had undergone emergency laparotomy associated with massive fluid resuscitation. There was major disparity in the frequency of IAP measurement and when to recommend abdominal decompression.

CONCLUSIONS

Despite widespread awareness of IAH and the ACS, many intensive care units never measure the IAP. When it is measured, the intravesical route is used exclusively. No consensus exists on optimal timing of measurement or when decompressive laparotomy should be performed.

Mesenteric venous thrombosis with transmural intestinal infarction: a population-based study

OBJECTIVE

To determine the cause-specific mortality from and incidence of transmural intestinal infarction caused by mesenteric venous thrombosis (MVT) in a population-based study and to evaluate the findings at autopsy by evaluating autopsies and surgical procedures.

METHODS

All clinical (n = 23,446) and forensic (n = 7569) autopsies performed in the city of Malmö between 1970 and 1982 (population 264,000 to 230,000) were evaluated. The autopsy rate was 87%. The surgical procedures were performed in 1970, 1976, and 1982. Autopsy protocols coded for intestinal ischemia or mesenteric vessel occlusion, or both, were identified in a database. In all, 997 of 23,446 clinical and 9 of 7,569 forensic autopsy protocols were analyzed. A 3-year sample of the surgical procedures, comprising 21.3% (11,985 of 56,251) of all operations performed during the entire study period, was chosen to capture trends of diagnostic and surgical activity. In a nested case-control study within the clinical autopsy cohort, four MVT-free controls, matched for gender, age at death, and year of death were identified for each fatal MVT case to evaluate the clinical autopsy findings.

RESULTS

Four forensic and 23 clinical autopsies demonstrated MVT with intestinal infarction. Seven patients were operated on, of whom six survived. The cause-specific mortality ratio was 0.9:1000 autopsies. The incidence was 1.8/100,000 person years. At autopsy, portal vein thrombosis and systemic venous thromboembolism occurred in 2 of 3 and 1 of 2 of the cases, respectively. Obesity was an independent risk factor for fatal MVT (P =.021).

CONCLUSIONS

The estimated incidence of MVT with transmural intestinal infarction was 1.8/100,000 person years. Portal vein thrombosis, systemic venous thromboembolism and obesity were associated with fatal MVT.

Continuous intra-abdominal pressure measurement technique

BACKGROUND

Abdominal compartment syndrome can develop within 12 hours of intensive care unit (ICU) admission in high-risk (shock/trauma, burn, pancreatitis, postabdominal aortic surgery) patients. The current standard of intra-abdominal pressure (IAP) measurement via the urinary catheter is labor intensive, and its intermittent nature could prevent timely recognition of significant changes in IAP. We propose that continuous IAP (CIAP) can be accurately measured via the irrigation port of a three-way catheter and has good agreement with the standard intermittent IAP (IIAP).

METHODS

CIAP was prospectively validated by comparing it with IIAP measurement in general surgical and trauma patients admitted to the ICU with a three-way urinary catheter. CIAP was measured via the irrigation port of the three-way catheter transduced to the bedside monitor as a continuous trace without intermittent clamping of the catheter. The standard IIAP measurements were performed via the urine drainage port after clamping the catheter and filling the bladder with 50 mL of 0.9% saline. Each patient had three separate paired measurements performed in standardized manner to compare CIAP with IIAP. Patients' demographics, injury severity, type of surgery, body mass index (BMI), and the paired individual IAP measurements were recorded. The paired measurements were compared using the Bland-Altman (B-A) method for comparing a new clinical measurement with an established one. Data are presented as mean +/- standard error of the mean.

RESULTS

During a 6-month period (ending in July 2003), 25 patients were investigated. The mean age was 61.5 +/- 4 years, 66% were men, and BMI was 29.2 +/- 2 kg/m(2). Six patients had vascular surgical, four elective and three urgent general surgical interventions. There were 12 trauma patients with ISS of 23 +/- 2. The CIAP was 14.2 +/- 0.66 (range 2 to 24) mm Hg, and the IIAP was 14.0 +/- 0.68 (range 3 to 24) mm Hg. Seventy-five percent of the measured pairs were exactly the same; in 21%, there was 1 mm Hg difference and in 4% 2 mm Hg. There was no measurement difference greater than 2 mm Hg. The mean difference between the CIAP and IIAP was 0.019 +/- 0.05 mmHg. The B-A statistics revealed that the difference between the means of measurements in each individual patient was between +/-1.96 SD (95% confidence intervals). The B-A scatter plot did not follow any patterns of typical systematic bias.

CONCLUSION

CIAP measurement with a three-way urinary catheter is a simple and accurate method for monitoring IAP. It has an excellent agreement with the IIAP over wide pressure ranges and should replace the current labor-intensive intermittent technique.

Subcutaneous Endoscopic Fasciotomy in a Porcine Model of Abdominal Compartment Syndrome: A Feasibility Study

PURPOSE

Treatment of abdominal compartment syndrome (ACS) involves abdominal decompression via a laparotomy, which can result in significant wound-related morbidity. Our aim was to determine if subcutaneous endoscopic abdominal fasciotomy in a porcine model of ACS is feasible and what effect it may have on intra-abdominal pressure (IAP) and superior mesenteric artery (SMA) blood flow.

MATERIALS AND METHODS

A total of 6 female pigs weighing 50 kg each were used for the study. Each animal underwent placement of an arterial line, pulmonary artery catheter, SMA blood flow probe, IAP catheter, and intra-abdominal saline infusion line. After endoscopic dissection of a subcutaneous pocket overlying the rectus muscles, saline was infused into the abdomen to a pressure of 40 mm Hg. Physiologic parameters were measured before and after bilateral endoscopic anterior rectus fasciotomies were performed, and analyzed with a paired t-test.

RESULTS

Mean subcutaneous dissection time was 42.5 +/- 11.3 minutes, and mean fasciotomy time was 5.5 +/- 2.3 minutes. There were no significant changes in heart rate, cardiac output, pO(2), or pH during the experiment. IAP increased exponentially as fluid was instilled into the abdomen. SMA blood flow decreased reliably and linearly with increasing IAP. Mean baseline IAP was 4.0 +/- 1.7 mm Hg. IAP decreased from 37 mm Hg to 25 mm Hg after fasciotomy (P < 0.001). Mean baseline SMA blood flow was 629 +/-164 mL/min. SMA blood flow improved from 265 mL/min to 389 mL/min after fasciotomy (P< 0.01).

CONCLUSION

Subcutaneous endoscopic abdominal fasciotomy is feasible and appears to lower IAP and raise SMA blood flow in a porcine model of ACS.

Modified Separation of Parts as an Intervention for Intraabdominal Hypertension and the Abdominal Compartment Syndrome in a Swine Model

Standard therapy for abdominal compartment syndrome is laparotomy. In many patients, laparotomy involves a recent incision; for others, volume of resuscitation may be the cause. The components separation technique allows difficult abdominal closure. The authors studied the effect of a modified separation of parts on abdominal compartment syndrome in an animal model. Eight pigs were instrumented for measurement of central venous pressure, mean arterial pressure, peak airway pressure, and intraabdominal pressure. Intraabdominal hypertension to 25 mmHg was established with intraperitoneal fluid infusion. Modified separation of parts was performed by sequential release of the abdominal wall layers. With increased intraabdominal pressure, mean arterial pressure (55.3 +/- 12.0 to 65.3 +/- 11.0), central venous pressure (7.7 +/- 2.4 to 13.3 +/- 6.9), and peak airway pressure (20.2 +/- 2.4 to 25.3 +/- 4.1; p < 0.05) also increased. Maximum intraabdominal pressure was 26.0 +/- 1.2 mmHg. Skin incision resulted in a decrease in intraabdominal pressure to 21.7 +/- 4.5, external oblique release to 18.3 +/- 3.9, internal oblique release to 13.2 +/- 4.0, and transversus muscle incision to 7.0 +/- 2.5 mmHg (p < 0.05). With completion of components separation, mean arterial pressure remained increased (63.2 +/- 16.9), central venous pressure decreased (6.8 +/- 3.6; p < 0.05), and peak airway pressure decreased (22.7 +/- 3.9; p < 0.05). Modified separation of parts technique effectively releases intraabdominal hypertension and reverses the physiologic derangements associated with abdominal compartment syndrome in the animal model.

Intraabdominal pressure in liver transplant recipients: incidence and clinical significance

BACKGROUND

The incidence and clinical relevance of increased intraabdominal pressure after orthotopic liver transplantation (OLT) has not yet been evaluated despite the finding that occurrence of this condition in postsurgical critically ill patients may impair various organ functions. The aim of this study was to assess whether the occurrence of abdominal hypertension among a population of OLT recipients was an important cofactor producing early postoperative complications.

METHOD

This prospective clinical study measured abdominal pressure every 6 hours during the intensive care unit (ICU) stay using the urinary bladder method. A value of >/=25 mm Hg was considered high. Hemodynamic status was simultaneously evaluated and renal function assessed based on the hourly urinary output, and by calculating serum creatinine on postoperative days 2 and 4. Renal failure was defined as a serum creatinine level of >1.5 mg/dL, or an increase in peak of >1 mg/L within 72 hours of surgery. The filtration gradient and patient outcomes were also considered.

RESULTS

Intraabdominal hypertension was observed in 32% of cases. The subjects displaying high IAP showed significantly lower artery pressure values (P <.01), but did not differ in terms of central venous pressure or cardiac output. High intraabdominal pressure was more frequently associated with renal failure (P <.01), a lower filtration gradient (P <.001), delayed postsurgical weaning from the ventilation (P <.001), and increased ICU mortality (P <.05). A receiver operator characteristic curve analysis showed that the critical IAP values, namely those with the best sensitivity/specificity, were 23 mm Hg for postoperative ventilatory delayed weaning (P <.05), 24 mm Hg for renal dysfunction (P <.05), and 25 mm Hg for death (P <.01).

CONCLUSIONS

Abdominal hypertension occurs frequently after OLT and may be associated with a complicated postoperative course.

Modified extraperitoneal endoscopic separation of parts for abdominal compartment syndrome

BACKGROUND

Standard therapy for abdominal compartment syndrome (ACS) is laparotomy and temporary abdominal wall closure with significant morbidity. The component separation technique allows for difficult abdominal closure. We studied a modified extraperitoneal endoscopic separation of parts technique on an animal model of ACS.

METHODS

Twelve anesthetized pigs were instrumented for measurement of central venous pressure, arterial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac output, and intraabdominal pressure (IAP). ACS to 25 mmHg was created by infusing saline into an intraabdominally placed bag. Animals were divided in two equal groups. Pigs in group A underwent minimally invasive resection of the nerves supplying the rectus muscles bilaterally. Pigs in group B underwent minimally invasive modified component separation technique bilaterally. Change in IAP and other physiological parameters were recorded.

RESULTS

(Group A) IAP increased significantly from 7.3 mmHg +/- 3.8 to 25.2 mmHg +/- 1.5 with infusion of saline. Following nerve transection on the right side there was a nonsignificant decrease in IAP from 25.2 mmHg +/- 1.5 to 22.3 mmHg +/- 1.4 and following nerve transection on the left side there was a further decrease in IAP to 20.3 mmHg +/- 1.9. (Group B) IAP increased significantly from 3.8 mmHg +/- 0.4 to 24.7 mmHg +/- 0.5 with infusion of saline. Following separation of parts on the right side there was a significant decrease in IAP from 24.7 mmHg +/- 0.5 to 15.0 mmHg +/- 1.7 and there was a further decrease in IAP to 11.3 mmHg +/- 1.4 following separation of parts on the left side. The only significant change in the physiological parameters measured was observed in CVP in both groups.

CONCLUSION

We present a porcine model of extraperitoneal endoscopic release of abdominal wall components as a treatment option for ACS.

Intra-abdominal hypertension and the abdominal compartment syndrome

The pressure within the abdominal cavity is normally little more than atmospheric pressure. However, even small increases in intra-abdominal pressure can have adverse effects on renal function, cardiac output, hepatic blood flow, respiratory mechanics, splanchnic perfusion and intracranial pressure. Although intra-abdominal pressure can be measured directly, this is invasive and bedside measurement of intra-abdominal pressure is usually achieved via the urinary bladder. This cheap, easy approach has been shown to produce results that correlate closely with directly measured abdominal pressures. Significant increases in intra-abdominal pressure are seen in a wide variety of conditions commonly encountered in the intensive care unit, such as ruptured aortic aneurysm, abdominal trauma and acute pancreatitis. Abdominal compartment syndrome describes the combination of increased intra-abdominal pressure and end-organ dysfunction. This syndrome has a high mortality, most deaths resulting from sepsis and multi-organ failure. Detection of abdominal compartment syndrome requires close surveillance of intra-abdominal pressure in patients thought to be at risk of developing intra-abdominal hypertension. The only available treatment for established abdominal compartment syndrome is decompressive laparotomy. Prevention of abdominal compartment syndrome after laparotomy by adoption of an open abdomen approach may be preferable in the patient at significant risk of developing intra-abdominal hypertension, but this has not been demonstrated in any large trials. Most surgeons prefer to adopt a 'wait and see' policy, only intervening when clinical deterioration is associated with a significant increase in intra-abdominal pressure.

Effects of the aldosterone receptor antagonist potassium canrenoate on renal blood flow and urinary output during prolonged increased intraabdominal pressure (IAP) in pigs

BACKGROUND

Increased intraabdominal pressure can be found after major abdominal trauma and necrotizing pancreatitis and is used during laparoscopic surgery. The purpose of this study was to investigate the effect of the aldosterone receptor antagonist (potassium canrenoate) on renal hemodynamics and urinary output in pigs during increased intraabdominal pressure (IAP).

METHODS

The IAP was kept at 30 mmHg for 3 h by instillation of Ringer's solution into the peritoneal cavity. Eight animals were treated with potassium canrenoate and eight animals served as controls. Renal blood flow, hormones in femoral artery blood, and the urinary output were measured.

RESULTS

The administration of potassium canrenoate was followed by increased aldosterone concentrations in arterial blood, increased blood concentration of potassium, and increased concentration of sodium in the urine, indicating satisfactory inhibition of aldosterone. Potassium canrenoate did not cause changes in cardiac output and arterial pressure. It did not affect the renal vascular resistance that increased at an IAP of 30 mmHg, or the renal blood flow that remained constant during the experiments. The group treated with potassium canrenoate had higher mean urinary output than the controls, but the difference was not significant.

CONCLUSION

Increased IAP in pigs is associated with markedly reduced urinary output and increased serum concentrations of aldosterone. Although the urinary output did not increase significantly, the increased sodium concentration in the urine of canrenoate-treated animals suggests that the high blood level of aldosterone contributes to the oliguria under increased IAP.

Endothelin-1 decreases postcapillary fluid efflux via prostacyclin release

BACKGROUND

Endothelin-1 (ET-1) decreases water efflux across the endothelial barrier (Lp). ET-1 may exert this permeability-decreasing effect by stimulating prostacyclin (PGI2) release. The purposes of this study were to (1) examine the effect of PGI2 on Lp, (2) measure Lp after inhibition of PGI(2) synthesis, and (3) determine the effect of ET-1 on Lp during inhibition of PGI2 production.

METHODS

After microscopic cannulation of mesenteric venules, Lp was measured during PGI2 infusion (0.1 micromol/L, 1 micromol/L, and 10 micromol/L; n = 6 in each group). Lp was also measured after 100 micromol/L of the PGI2 synthase inhibitor, tranylcypromine (TCPN) (n = 6). Finally, the influence of ET-1 on Lp during PGI2 synthase inhibition was assessed (n = 6).

RESULTS

Compared to baseline Lp of 1.05 +/- 0.06, PGI2 decreased Lp at 1 micromol/L (Lp = 0.63 +/- 0.03, P < .003) and 10 micromol/L (Lp = 0.52 +/- 0.04, P < .0001). TCPN increased Lp compared to baseline (P < .0001). Compared to ET-1 alone, venules perfused with TCPN + ET-1 increased Lp (P < .005). Units for Lp ) are 10(-7) cm x sec(-1) x cmH2O(-1).

CONCLUSIONS

We found that (1) PGI2 decreases Lp, (2) inhibition of PGI2 synthesis increases Lp, and (3) permeability-decreasing effects of ET-1 can be blocked by inhibiting PGI2 synthesis. These data suggest that constitutive production of PGI2 modulates basal microvessel permeability and that ET-1 may exert its permeability-decreasing effect via the stimulation of PGI2 release.

Endothelin-1 decreases microvessel permeability after endothelial activation

BACKGROUND

Endothelin-1 (ET-1) is a potent vasoconstrictor that is released during shock and sepsis. We hypothesized that ET-1 plays a role in the modulation of the elevated microvascular permeability state of the activated endothelium.

METHODS

Hydraulic permeability (Lp) was measured using the modified Landis micro-occlusion technique. The effect of different ET-1 doses on Lp was determined by obtaining paired measures of Lp at baseline and after the vessels were perfused with ET-1 at doses of 2.0 pg/mL (n = 6), 20 pg/mL (n = 6), 200 pg/mL (n = 6), or 2,000 pg/mL (n = 6). To evaluate the effects of ET-1 in the activated endothelium, additional vessels were perfused with either 10 micromol/L adenosine triphosphate (ATP) (n = 6) or 1 nmol/L bradykinin (n = 6). The vessels were then perfused with 200 pg/mL ET-1 followed by the final L determination.

RESULTS

ET-1 significantly decreased Lp at doses of 20 pg/mL (p = 0.03), 200 pg/mL (p = 0.03), and 2,000 pg/mL (p = 0.01). Endothelial activation with ATP and bradykinin increased Lp to 4.21 +/- 0.39 (p < 0.0001) and 2.72 +/- 0.24 (p = 0.001), respectively. ET-1 significantly decreased the Lp to 1.99 +/- 0.48 after activation with ATP (p = 0.004). ET-1 also decreased the Lp to 1.10 +/- 0.19 after activation with bradykinin (p = 0.001). Units for Lp are x10(-7) cm x s(-1) x cm H2O(-1).

CONCLUSION

In this model, ET-1 attenuated the increase in microvascular permeability that can be seen in inflamed vessels. In addition to its vasopressor function, ET-1 may be of benefit in pathophysiologic states by decreasing third-space fluid loss. This receptor-mediated function of ET-1 may be amenable to pharmacologic manipulation.

Endovascular Embolization of Spontaneous Retroperitoneal Hemorrhage Secondary to Anticoagulant Treatment

The purpose of this study was to report a single hospital's experience of endovascular treatment of patients with retroperitoneal hemorrhage (RPH) secondary to anticoagulant treatment. Ten consecutive patients treated in an intensive care unit and needing blood transfusions due to RPH secondary to anticoagulation were referred for digital subtraction angiography (DSA) to detect the bleeding site(s) and to evaluate the possibilities of treating them by transcatheter embolization. DSA revealed bleeding site(s) in all 10 patients: 1 lumbar artery in 4 patients, 1 branch of internal iliac artery in 3 patients and multiple bleeding sites in 3 patients. Embolization could be performed in 9 of them. Coils, gelatin and/or polyvinyl alcohol were used as embolic agents. Bleeding stopped or markedly decreased after embolization in 8 of the 9 (89%) patients. Four patients were operated on prior to embolization, but surgery failed to control the bleeding in any of these cases. Abdominal compartment syndrome requiring surgical or radiological intervention after embolization developed in 5 patients. One patient died, and 2 had sequelae due to RPH. All 7 patients whose bleeding stopped after embolization had a good clinical outcome. Embolization seems to be an effective and safe method to control the bleeding in patients with RPH secondary to anticoagulant treatment when conservative treatment is insufficient.

Abdominal compartment syndrome: urological aspects

ACS is prevalent in various surgical conditions and in a large percentage of critically ill patients. Measuring the IAP is important in the early diagnosis of ACS and can be easily done by measuring the intravesical pressure. ACS adversely affects many organ systems; the pathogenesis of renal dysfunction is probably multifactorial, from a combination of reduced cardiac output, reduced GFR mediated by secretion of renin and angiotensin, aldosterone-mediated water reabsorption, increased renal parenchymal pressure and direct compression of the renal vein. Successful treatment requires a high index of suspicion, prompt recognition and early surgical abdominal decompression.

Long-Term Physical, Mental, and Functional Consequences of Abdominal Decompression

BACKGROUND

The long-term physical, mental, and functional consequences of abdominal decompression for intra-abdominal hypertension are unknown.

METHODS

Thirty patients in various stages of abdominal decompression and delayed fascial closure for massive incisional hernia completed the SF-36 Health Survey and answered questions regarding their employment and pregnancy status.

RESULTS

Patients awaiting abdominal wall reconstruction demonstrated significantly decreased perceptions of physical, social, and emotional health (p < 0.05), whereas patients who had completed definitive fascial closure demonstrated physical and mental health scores equivalent to the U.S. general population. Ultimately, 78% of patients employed before decompression returned to work.

CONCLUSION

Abdominal decompression with skin grafting and delayed fascial closure initially decreases patient perception of physical, social, and emotional health, but subsequent abdominal wall reconstruction restores physical and mental health to that of the U.S. general population. Abdominal decompression does not prevent return to gainful employment and should not be considered a permanently disabling condition.

Patients with impending abdominal compartment syndrome do not respond to early volume loading

BACKGROUND

It is recommended that patients with impending abdominal compartment syndrome (ACS) should be volume loaded to insure the adequate preload. We evaluated our prospective resuscitation database to determine how patients who developed ACS differ from non-ACS patients in response to early volume loading.

METHODS

Over 36 months, 152 consecutive high-risk patients were resuscitated by a standard intensive care unit (ICU) protocol that escalates interventions in nonresponders. Interventions, responses, and outcomes are prospectively collected and the characteristics of ACS and non-ACS patients were compared.

RESULTS

Twenty-three patients (15%) developed ACS and were decompressed 8 +/- 1 hours after ICU admission. The ACS and non-ACS patients had similar demographics and injury severity. The severity of pre-ICU shock tended to be greater in the ACS patients. During the first 8 hours of ICU resuscitation, patients who developed ACS received more blood transfusions (11 +/- 2 versus 2 +/- 0.2 units; P<0.05) and crystalloids (13 +/- 2 versus 4 +/- 0.3 L; P<0.05). As a result, pulmonary capillary wedge pressure increased more in the ACS patients (20 +/- 1.5 versus 15 +/- 0.5 mm Hg; P<0.05), but comparatively the cardiac index did not (3.2 +/- 0.2 versus 4.2 +/- 0.1 L/min/m(2); P<0.05) and the ACS patients developed pathologic elevations of gastric regional CO(2) pressures (70 +/- 7 versus 48 +/- 1 mm Hg P<0.05).

CONCLUSIONS

Conventional preload directed resuscitation to enhance cardiac function is not effective in patients with impending ACS, and this traditional resuscitation strategy is detrimental in this subgroup of patients.

Changing patterns in the management of penetrating abdominal trauma: the more things change, the more they stay the same

BACKGROUND

Damage control surgery (DCS) and treatment of abdominal compartment syndrome have had major impacts on care of the severely injured. The objective of this study was to see whether advances in critical care, DCS, and recognition of abdominal compartment syndrome have improved survival from penetrating abdominal injury (PAI).

METHODS

The care of 250 consecutive patients requiring laparotomy for PAI (1997-2000) was reviewed retrospectively. Organ injury patterns, survival, and use of DCS and its impact on outcome were compared with a similar experience reported in 1988.

RESULTS

Two hundred fifty patients had a positive laparotomy for PAI. Twenty-seven (10.8%) required abdominal packing and 45 (17.9%) did not have fascial closure. Seven (2.8%) required emergency department thoracotomy and 21 (8.4%) required operating room thoracotomy. Two hundred seventeen (86.8%) survived overall. Small bowel (47.2%), colon (36.4%), and liver (34.4%) were most often injured. Mortality was associated with the number of organs injured (odds ratio, 1.98; 95% confidence interval, 1.65-2.37; p < 0.001). Vascular injury was a risk factor for mortality (p < 0.001), as was need for DCS (p < 0.001), emergency department thoracotomy (p < 0.001), and operating room thoracotomy (p < 0.001). Seventy-nine percent of deaths occurred within 24 hours from refractory hemorrhagic shock. DCS was used in 17.9% (n = 45) versus 7.0% (n = 21) in 1988, with a higher survival rate (73.3% vs. 23.8%, p < 0.001). DCS was associated with significant morbidity including sepsis (42.4%, p < 0.001), intra-abdominal abscess (18.2%, p = 0.009), and gastrointestinal fistula (18.2%, p < 0.001).

CONCLUSION

Penetrating abdominal organ injury patterns and survival from PAI have remained similar over the past decade. Death from refractory hemorrhagic shock in the first 24 hours remains the most common cause of mortality. DCS and the open abdomen are being used more frequently with improved survival but result in significant morbidity.

Vacuum-Assisted Wound Closure Achieves Early Fascial Closure of Open Abdomens after Severe Trauma

BACKGROUND

This study reviews the efficacy of vacuum-assisted wound closure (VAWC) to obtain primary fascial closure of open abdomens after severe trauma.

METHODS

The study population included shock resuscitation patients who had open abdomens treated with VAWC. The VAWC dressing was changed at 2- to 3-day intervals and downsized as fascial closure was completed with interrupted suture. The Trauma Research Database and the medical records were reviewed for pertinent data.

RESULTS

Over 26 months, 35 patients with open abdomens were managed by VAWC. Six died early, leaving 29 patients who were discharged. Of these, 25 (86%) were successfully closed using VAWC at a mean of 7 +/- 1 days (range, 3-18 days). Of the four patients that failed VAWC, two developed fistulas. No patients developed evisceration, intra-abdominal abscess, or wound infection.

CONCLUSION

VAWC achieved early fascial closure in a high percentage of open abdomens, with an acceptable rate of complications.