Ronald J. Simon

INTRA-ABDOMINAL HYPERTENSION AND THE ABDOMINAL COMPARTMENT SYNDROME

IAH causes multiple and profound physiologic abnormalities both within and outside the abdomen. IAP monitoring is easily performed by bladder measurements. Careful monitoring and prompt recognition and treatment of IAP are critical in patients after damage control surgery because IAH is extremely common in these patients. Use of mesh fascial prostheses at the initial celiotomy in high-risk patients may prevent the deleterious effects of IAH. IAH should be considered an earlier manifestation of ACS. Surgical intervention should be indicated by IAH and not delayed until ACS is clinically apparent.

Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: prophylaxis, incidence, and clinical relevance to gastric mucosal pH and abdominal compartment syndrome.

OBJECTIVE To define the incidence, prophylaxis, and treatment of intra-abdominal hypertension (IAH) and its relevance to gut mucosal pH (pHi), multiorgan dysfunction syndrome, and the abdominal compartment syndrome (ACS). METHODS Seventy patients in the SICU at a Level I trauma center (1992-1996) with life threatening penetrating abdominal trauma had intra-abdominal pressure estimated by bladder pressure. pHi was measured by gastric tonometry every 4 to 6 hours. IAH (intra-abdominal pressure> 25 cm of H2O) was treated by bedside or operating room laparotomy. RESULTS Injury severity was comparable between patients who had mesh closure as prophylaxis for IAH (n = 45) and those who had fascial suture (n = 25). IAH was seen in 10 (22.2%) in the mesh group versus 13 (52%) in the fascial suture group (p = 0.012) for an overall incidence of 32.9%. Forty-two patients had pHi monitoring, and 11 of them had IAH. Of the 11 patients, eight patients (72.7%) had acidotic pHi (7.10 +/- 0.2) with IAH without exhibiting the classic signs of ACS. The pHi improved after abdominal decompression in six and none developed ACS. Only two patients with IAH and low pHi went on to develop ACS, despite abdominal decompression. Multiorgan dysfunction syndrome points and death were less in patients without IAH than those with IAH and in patients who had mesh closure. CONCLUSIONS IAH is frequent after major abdominal trauma. It may cause gut mucosal acidosis at lower bladder pressures, long before the onset of clinical ACS. Uncorrected, it may lead to splanchnic hypoperfusion, ACS, distant organ failure, and death. Prophylactic mesh closure of the abdomen may facilitate the prevention and bedside treatment of IAH and reduce these complications.

A Critical Evaluation Of Laparoscopy In Penetrating Abdominal Trauma

One hundred hemodynamically stable patients with penetrating abdominal trauma (65, stab wounds, 35, gunshot wounds) were evaluated with laparoscopy. Sixty percent of the patients had wounds in the thoracoabdominal area or the upper abdominal quadrants and 25% had injuries located in the lower abdomen and flanks. Fifteen percent had epigastric wounds. Twenty-two stabs and 21 gunshots had not penetrated the peritoneum (negative laparoscopic results). Fifty-seven patients had peritoneal penetration and were noted to have hemoperitoneum only (n = 14), hemoperitoneum and solid organ injuries (n = 23), diaphragmatic lacerations (n = 17), and hollow viscus injuries (n = 2) on laparoscopic examination. Three of the 57 patients, one with omental herniation only and two with low grade nonbleeding lacerations of the liver, were managed uneventfully without laparotomy. The remaining 54 patients underwent laparotomy with confirmation of the laparoscopic findings. Seven patients (three with stab wounds and four with gunshots) had additional GI tract injuries seen at laparotomy. The diagnostic accuracy of laparoscopy was excellent for hemoperitoneum, solid organ injuries, diaphragmatic lacerations, and retroperitoneal hematomas. For GI injuries, laparoscopy was found to have a 100% specificity but only a 18% sensitivity. The majority of these discordant findings occurred in epigastric SWs and flank and lower quadrant GSWs, all in patients with undetected hollow viscus injuries. The major role of laparoscopy in penetrating abdominal trauma is in avoiding unnecessary laparotomy in tangential SWs and GSWs. It is excellent for evaluating the diaphragm in thoracoabdominal wounds. Caution is urged in excluding hollow viscus injuries based on laparoscopy.

Laparoscopy in the evaluation of the intrathoracic abdomen after penetrating injury.

Penetrating trauma to the intrathoracic abdomen is a difficult clinical problem, especially with reference to the detection of diaphragmatic injuries. A retrospective analysis of 657 laparotomies for penetrating abdominal trauma at our institution revealed 78 laparotomies with negative results. The majority (44.8%) were for wounds in the lower chest and upper abdomen. The role of laparoscopy in evaluating these difficult areas was studied in 40 (34 stab wounds and 6 gunshot injuries) patients. Fifteen stab wounds and five gunshot wounds were nonpenetrating. Laparoscopy revealed eight clinically unsuspected diaphragmatic lacerations in seven patients. Twenty patients had hemoperitoneum. Five patients with omental bleeding and abdominal wall bleeding and four with nonbleeding liver lacerations underwent nontherapeutic laparotomies. One patient with a nonbleeding liver laceration was observed successfully without laparotomy. Ten of the 20 patients with hemoperitoneum had therapeutic laparotomies. The incidence of diaphragmatic lesions discovered by laparoscopy in this series was comparable with that reported after a mandatory laparotomy for thoracoabdominal wounds. It is concluded that laparoscopy is an excellent modality for the evaluation of the intrathoracic abdomen and the diaphragm.

Intestinal permeability correlates with severity of injury in trauma patients

BACKGROUND Increased intestinal permeability (IP) and the release of toxic intraluminal materials have been implicated in the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF) observed in patients after severe trauma. Previous studies of intestinal permeability have failed to demonstrate a correlation between early measurements of IP and indicators of injury severity. This study examines the relationship between standard measures of injury severity and the early (day 1) and delayed (day 4) changes in IP. Associations between IP and the development of SIRS, MOF, and infectious complications were also studied. METHODS The metabolically inactive markers lactulose (L) and mannitol (M) were used to measure IP in 29 consecutive patients who sustained injuries that required admission to the surgical intensive care unit and in 10 healthy control subjects. Measurements were made within 24 hours of admission and on hospital day 4. Severity of injury was assessed by A Severity Characterization of Trauma (ASCOT), Trauma and Injury Severity Score (TRISS), Injury Severity Score (ISS), Revised Trauma Score (RTS), and Acute Physiology and Chronic Health Evaluation (APACHE) II score. Postinjury infections and parameters of SIRS and MOF were recorded. RESULTS The IP of healthy volunteers (L/M, 0.025 +/- 0.008) was within the normal range (L/M < or = 0.03), whereas the average IP in injured patients was increased both within 24 hours (L/M, 0.139 +/- 0.172) and on the fourth hospital day (L/M, 0.346 +/- 0.699). No significant correlation between severity of injury and increased IP was seen within 24 hours of injury. A significant correlation was seen on hospital day 4, however, with all severity indices measured (ASCOT: r = 0.93, R2 = 0.87, p < 0.001; TRISS: r = 0.93, R2 = 0.87, p < 0.001; ISS: r = 0.84, R2 = 0.70, p < 0.001; RTS: r = 0.68, R2 = 0.47, p = 0.002; APACHE II score: r = 0.51, R2 = 0.26, p = 0.04). Patients with markedly increased IP (L/M > or = 0.100) experienced a significant increase in the development of SIRS (83 vs. 44%; p = 0.03) and subsequent infectious complications (58 vs. 13%; p = 0.01) and showed close correlation with the multiple organ dysfunction scores (r = 0.87, R2 = 0.76, p < 0.001). CONCLUSION These observations demonstrate that the increased IP observed after trauma correlates with severity of injury only after 72 to 96 hours and not within the initial 24 hours of injury. A large increase in IP is associated with the development of SIRS, multiple organ dysfunction, and an increased incidence of infectious complications.

Candiduria as an early marker of disseminated infection in critically ill surgical patients: the role of fluconazole therapy.

The significance of candiduria in critically ill patients remains unclear. It may represent harmless colonization or a potentially life-threatening infection. We analyzed 47 patients in the surgical intensive care unit (SICU) (trauma: 20, general surgery: 15, neurosurgery: 12) who had candiduria, defined by a colony count greater than 100,000/mL. Twenty-seven of these patients were studied retrospectively. Twenty were evaluated prospectively. All patients were receiving broad-spectrum antibiotics for bacterial infections. Retrospective group: ten patients (group A) did not develop disseminated candidiasis, whereas 17 patients (group B) did. Group B had higher APACHE II scores on admission (13.4 +/- 7.8) and at the time of candiduria (13.7 +/- 4.4) when compared with group A [admission: 5.0 +/- 4.6; candiduria: 6.7 +/- 3.6 (p < 0.02)]. In group B, disseminated candidiasis was not diagnosed and treated until 9.9 +/- 4.4 days after development of candiduria. Prospective group: twenty patients with candiduria were treated with systemic fluconazole (group C) at the time of candiduria. The APACHE II scores of group C on admission (12.8 +/- 3.9) and at the time of candiduria (10.5 +/- 4.0) were comparable with those of group B. No patient in Group C developed disseminated candidiasis. The septic mortality rates of groups A, B, and C were 0%, 53%, and 5%, respectively (p < 0.05-0.0001). In patients exhibiting ongoing sepsis and organ failure (high APACHE scores), candiduria may be an early indicator of systemic infection. Diagnosis of disseminated infection and its treatment may be delayed if conventional criteria for candidiasis (positive blood cultures, multiple site isolation) are awaited.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemorrhage lowers the threshold for intra-abdominal hypertension-induced pulmonary dysfunction.

BACKGROUND Intra-abdominal hypertension has been associated with pulmonary and cardiac dysfunctions. We have noted in the clinical scenario of hemorrhagic shock and resuscitation that avoidance of even moderate levels of increased intra-abdominal pressure, using prophylactic decompression, improves outcomes when compared with patients who were decompressed when intra-abdominal pressures went over 20 cm H2O. We hypothesized that prior hemorrhage and resuscitation exacerbates the cardiopulmonary dysfunction associated with intra-abdominal hypertension. METHODS Ten anesthetized pigs underwent placement of arterial and pulmonary artery catheters and a Silastic intra-abdominal catheter for measuring and manipulating intra-abdominal pressure. Group 1 animals (n = 5) were subjected to increasing intra-abdominal pressures at 10 mm Hg increments up to a level of 40 mm Hg. Group 2 animals (n = 5) were exposed to a severe hemorrhage and resuscitation before the increasing intra-abdominal pressure protocol. RESULTS Compared with baseline, hemorrhage and resuscitation caused a significant deterioration in cardiac output at intra-abdominal pressures of 10 mm Hg and above. Oxygenation was reduced at 30 and 40 mm Hg. These changes were not seen in group 1 animals. A significant difference was found between groups 1 and 2 in VT, PaCO2, and PaCO2/FIO2 ratio at an intra-abdominal pressure of 20 mm Hg. This difference was not seen at lower or higher pressures. CONCLUSIONS Prior hemorrhage and resuscitation caused an earlier decline in cardiopulmonary function in the setting of increased intra-abdominal pressure. These data suggest that, when interpreting intra-abdominal pressures, the clinical scenario must be considered. Prior hemorrhage and resuscitation produce the adverse consequences of intra-abdominal hypertension at lower pressures than when intra-abdominal hypertension is the only insult.

Effect of Hemorrhage on Superior Mesenteric Artery Flow during Increased Intra-abdominal Pressures

BACKGROUND Elevations in intra-abdominal pressure (IAP) adversely affect organ function. Prior hemorrhage and resuscitation exacerbates the cardiac and pulmonary effects of IAP. We have recently shown that superior mesenteric artery flow (SMAF) is reduced with increasing IAP. This study was designed to determine whether and how hemorrhage and resuscitation affects SMAF with increasing IAP. METHODS Ten pigs were divided into two groups after placement of a Doppler flow probe around the proximal SMA and insertion of a pulmonary artery (PA) catheter. Group 1 underwent intraperitoneal infusion of fluid to increase IAP to 10, 20, 30, and 40 mm Hg followed by a 20-minute equilibration period at each IAP. Group 2 was hemorrhaged 20% of circulating volume followed by standard resuscitation. After equilibration, this group had IAP increased in the same manner as group 1. Cardiac output (CO), PA pressures, and SMAF were recorded 1 hour after laparotomy and after equilibration at each IAP. Comparisons were made using repeated measures of analysis of variance, Students t test, and linear regression analysis. RESULTS In group 2, a reduction in SMAF was noted at 30 and 40 mm Hg of IAP when compared with baseline (p = 0.009). This reduction was not seen in group 1. There was also a significant (p = 0.001) reduction in CO between baseline and all levels of increased IAP in group 2. This decrease was again not seen in group 1. The correlation between CO and SMAF in group 2 was r = 0.74, r2 = 0.55, p = 0.0001. There was no significant correlation between CO and SMAF in group 1. CONCLUSION SMAF and CO are reduced with increasing IAP to a greater degree when preceded by hemorrhage and resuscitation. Although there is a strong correlation between the reductions in CO and SMAF, the reduction in SMAF is greater than the reduction in CO. This finding suggests that optimizing cardiac function alone during periods of even moderate levels of increased IAP may be inadequate to normalize SMAF. This lends further support for early abdominal decompression in the treatment of trauma patients with increased IAP.

COMPLEX DUODENAL INJURIES

Duodenal trauma, with early diagnosis and prompt treatment, can be managed effectively by simple surgical techniques. Severe duodenal injuries and those associated with major destruction of adjacent structures (the pancreaticobiliary complex or abdominal vessels) require a more thoughtful strategy that incorporates a careful consideration of the physiologic stability of the patient and the extent of local destruction. Figure 8 summarizes these concepts in an algorithm.

Impact of Increased Use of Laparoscopy on Negative Laparotomy Rates after Penetrating Trauma

BACKGROUND Our institution was one of the first to report the use of laparoscopy in the management of penetrating abdominal trauma (PAT) in 1977. Despite early interest, laparoscopy was rarely used. Changes in 1995 resulted in an increase in interest and use of laparoscopy. We present our recent experience with laparoscopy. METHODS Our trauma registry and operative log were used to identify patients with blunt and penetrating injuries to the abdomen, back, and flank who underwent laparotomy or laparoscopy during the past 5 years. Patient demographics, operative findings, complications, and length of stay were reviewed. The number of laparoscopic explorations, therapeutic, nontherapeutic, and negative laparotomies were trended. RESULTS There were 429 abdominal explorations for trauma. The rate of laparoscopy after penetrating injury increased from 8.7% to 16%, and after stab wounds from 19.4% to 27%. There was an associated decrease in the negative laparotomy rate. Laparoscopy prevented unnecessary laparotomy in 25 patients with PAT. Four patients with diaphragm injuries underwent repair laparoscopically. CONCLUSION An aggressive laparoscopic program can improve patient management after PAT.