Modified rapid deployment hemostat bandage reduces blood loss and mortality in coagulopathic pigs with severe liver injury

BACKGROUND

Hemostasis can be difficult to achieve after blunt abdominal trauma, especially if the patient is coagulopathic. The U.S. Food and Drug Administration has recently approved a hemostatic dressing for treating bleeding after extremity trauma (RDH bandage; Marine Polymer Technologies, Cambridge, MA). It has not been evaluated for internal bleeding after trauma. We redesigned this dressing for internal use, and then tested whether this modified bandage (Miami-modified Rapid Deployment Hemostat) could achieve hemostasis when used as an adjunct to standard laparotomy pad packing in a pig model of severe liver injury with coagulopathy.

METHODS

Anesthetized swine (35-45 kg) received an isovolemic 45% blood volume replacement with refrigerated Hextend (6% hetastarch). Core body temperature was maintained at 33-34 degrees C with intra-abdominal ice packs. A coagulopathic condition was documented by thromboelastography. At this point a severe liver injury was induced by the avulsion of the left lateral hepatic lobe, then the pigs were randomized to treatment with either standard abdominal packing (control) or packing plus Miami-modified Rapid Deployment Hemostat. Two series of experiments were conducted. In series one (n = 14), the abdomen was closed and the animals were observed with no resuscitation. After one hour, the abdomen was opened, the packing was removed and the presence of bleeding was noted. In series two (n = 10), the abdomen was closed and the animal resuscitated with one unit of blood plus as much lactated Ringers intravenous fluid (IVF) as required to maintain a mean arterial pressure (MAP) > 70 mm Hg. After one hour, the packing was removed, the abdomen closed, and data were collected for an additional two hours.

RESULTS

Series one: 6/7 animals in the control group had continued bleeding at one hour; 1/7 animals in the treatment group had active bleeding (p = 0.0291). Series two: With control vs. Miami-modified Rapid Deployment Hemostat, the three-hour survival was zero vs. 80% (p = 0.0476). The total blood loss was 1.2 +/- 0.1 vs. 0.3 +/- 0.1 mL/kg/min (p = 0.001) and the IVF requirement was 1.6 +/- 0.3 vs. 0.6 +/- 0.3 mL/kg/min (p = 0.026).

CONCLUSIONS

The Miami-modified Rapid Deployment Hemostat bandage significantly reduced mortality, blood loss, and fluid requirements when used as an adjunct to standard abdominal packing following severe liver injury in coagulopathic pigs [corrected].

Early coagulopathy predicts mortality in trauma

BACKGROUND

Coagulopathy and hemorrhage are known contributors to trauma mortality; however, the actual relationship of prothrombin time (PT) and partial thromboplastin time (PTT) to mortality is unknown. Our objective was to measure the predictive value of the initial coagulopathy profile for trauma-related mortality.

METHODS

We reviewed prospectively collected data on trauma patients presenting to a Level I trauma center. A logistic regression analysis was performed of PT, PTT, platelet count, and confounders to determine whether coagulopathy is a predictor of all-cause mortality.

RESULTS

From a trauma registry cohort of 20103 patients, 14397 had complete disposition data for initial analysis and 7638 had complete data for all variables in the final analysis. The total cohort was 76.2% male, the mean age was 38 years (range, 1-108 years), and the median Injury Severity Score was 9. There were 1276 deaths (all-cause mortality, 8.9%). The prevalence of coagulopathy early in the postinjury period was substantial, with 28% of patients having an abnormal PT (2994 of 10790) and 8% of patients having an abnormal PTT (826 of 10453) on arrival at the trauma bay. In patients with disposition data and a normal PT, 489 of 7796 died, as compared with 579 of 2994 with an abnormal PT (6.3% vs. 19.3%; chi2 = 414.1, p < 0.001). Univariate analysis generated an odds ratio of 3.6 (95% confidence interval [CI], 3.15-4.08; p < 0.0001) for death with abnormal PT and 7.81 (95% CI, 6.65-9.17; p < 0.001) for deaths with an abnormal PTT. The PT and PTT remained independent predictors of mortality in a multiple regression model, whereas platelet count did not. The model also included the independent risk factors age, Injury Severity Score, scene and trauma-bay blood pressure, hematocrit, base deficit, and head injury. The model generated an adjusted odds ratio of 1.35 for PT (95% CI, 1.11-1.68; p < 0.001) and 4.26 for PTT (95% CI, 3.23-5.63; p < 0.001).

CONCLUSION

The incidence of coagulation abnormalities, early after trauma, is high and they are independent predictors of mortality even in the presence of other risk factors. An initial abnormal PT increases the adjusted odds of dying by 35% and an initial abnormal PTT increases the adjusted odds of dying by 326%.

The risk of death for Jehovah's Witnesses after major trauma

BACKGROUND

Trauma surgeons are faced with life-threatening blood loss in patients such as Jehovah's Witnesses. We assessed and compared the risks of death after major trauma for Jehovah's Witnesses and other religious groups.

METHODS

A retrospective cohort study was conducted between August 1992 and September 1999 in a Level I academic trauma center. Statistical methods included Tukey's one-way analysis of variance, chi2 analysis, and bivariate and multivariate logistic regression analyses.

RESULTS

The cohort consisted of 556 patients: 82 Jehovah's Witnesses (14.7%), 52 Baptists (9.4%), 101 Catholics (18.2%), and 321 patients belonging to other religious groups (57.7%). Mean Injury Severity Scores for 433 patients were 10.3 +/- 9, 8.9 +/- 10, 10.3 +/- 11, and 11.3 +/- 14, respectively. There were no significant differences in mean Injury Severity Scores between religious groups, and no statistically significant associations between religion and Injury Severity Scores were identified. Significant predictors of mortality were age, systolic blood pressure at admission, Glasgow Coma Scale score, and type of trauma. Jehovah's Witnesses were 6% more likely to die after major trauma than Baptists, 20% more likely than Catholics, and as likely as patients from any other religious groups.

CONCLUSION

After controlling for age, race, systolic blood pressure, Glasgow Coma Scale score, and type of trauma, Jehovah's Witnesses have a nonsignificant increased risk of death after major trauma compared with other religious groups.

Oxygen therapeutics in trauma and surgery

A number of oxygen therapeutics have completed safety trials and are now undergoing efficacy evaluation in multicenter phase III trials in North America and Europe. There are numerous potential advantages of these solutions when compared with packed red blood cells. They are readily available and have a long shelf life; do not require type and cross-matching; are virtually free of viral or bacterial contamination; have a much lower viscosity than blood; and may lack the immunosuppressive effects of blood. These products may also deliver more oxygen per unit mass than an equivalent amount of hemoglobin from red blood cells, providing the potential to sustain life in certain clinical situations. A few problems remain, including short biologic half-life, which may limit the application to times when the patient is most acutely anemic (i.e., in the intraoperative or immediate perioperative phase) or for emergent use. Nevertheless, a safe, effective alternative therapy providing oxygen delivery characteristics comparable to red blood cells may soon be available that could have significant impact on the way that we resuscitate trauma patients.

Gastric tonometry: the role of mucosal pH measurement in the management of trauma

Effective management of hemorrhagic shock depends on titration of therapies against reliable resuscitation end points. Conventional clinical and laboratory indexes of shock are often slow to respond to progressive circulatory compromise. GI mucosal ischemia resulting from redistribution of blood flow may, however, precede uncompensated shock and may compound the initial hemorrhagic insult by touching off cascades of inflammatory responses. Trauma patients with evidence of subclinical GI ischemia have been shown to have poor outcomes. Gastric tonometry, by detecting the presence of gastric intramucosal acidosis as a proxy of splanchnic hypoperfusion, may facilitate more timely and rational shock resuscitation. This article reviews the development and validation of gastric tonometry and summarizes the clinical studies that have used this modality to guide the management of shock in trauma patients.

Predicting the need for laparotomy in pediatric trauma patients on the basis of the ultrasound score

BACKGROUND

It is possible to quantify the amount of hemoperitoneum seen on focused assessment with sonography for trauma (FAST) using a simple scoring system that had previously been shown to correlate with the need for subsequent laparotomy in adults. A score of 3 or greater was shown to be highly accurate in predicting the need for laparotomy. We hypothesized that this scoring system might also predict the need for laparotomy in pediatric trauma patients.

METHODS

We retrospectively reviewed all records for patients 15 years and younger who underwent FAST after blunt trauma. A "positive" ultrasound examination was defined as one containing free intraperitoneal fluid with or without solid organ injury. The ultrasound score (USS) was defined as the depth of the deepest pocket of fluid collection measured in centimeters plus the number of additional spaces where fluid was seen.

RESULTS

Thirty-eight (19.6%) of 193 patients who had FAST performed had positive ultrasound examinations. Thirty-seven patients with complete records were analyzed. There were no differences between patients with a USS < or = 3.0 and those with a USS > 3.0 in terms of admission pulse, Glasgow Coma Scale score, Injury Severity Score, or the proportion of patients who were initially hypotensive. One of 22 patients with a USS < or = 3.0 required therapeutic laparotomy versus 8 of 15 patients with a USS > 3.0 ( = 0.002). For a USS > 3.0, sensitivity, specificity, and accuracy in predicting therapeutic laparotomy were 89%, 75%, and 78%, respectively.

CONCLUSION

Ultrasound quantification of hemoperitoneum by a simple scoring system may serve as a useful adjunct to traditional clinical parameters in predicting the need for subsequent laparotomy in pediatric patients. Prospective validation with a larger study is required.

Pro/con clinical debate: antibiotics are important in the management of patients with pancreatitis with evidence of pancreatic necrosis

Pancreatitis is not an infrequent diagnosis in patients admitted to the intensive care unit. Prolonged stays, intense resource utilization and high morbidity/mortality are commonplace in such patients. Management for the most part is supportive, with the surgical team keeping close watch to intervene as the need arises. Over the past few decades there has been considerable debate regarding the usefulness of systemic antibiotics to prevent infectious complications in patients with evidence of pancreatic necrosis. In the present article of Critical Care, two expert groups debate the two sides of this contentious antibiotic issue.

Early injection of high-dose recombinant factor VIIa decreases blood loss and prolongs time from injury to death in experimental liver injury

BACKGROUND

Recombinant factor VIIa (rFVIIa) is used for treatment of bleeding episodes in hemophilia patients who develop inhibitors to factors VIII and IX. We tested the hypothesis that administration of rFVIIa early after injury would decrease bleeding and prolong the time from injury to death after experimental hepatic trauma.

METHODS

Anesthetized swine were cannulated for blood sampling and hemodynamic monitoring. Avulsion of the left median lobe of the liver induced uncontrolled hemorrhage. After a 10% reduction in mean arterial pressure, animals (n = 8 per group) were blindly randomized to receive intravenous rFVIIa 180 microg/kg, rFVIIa 720 microg/kg, or placebo. Pathologic examination of brain, lung, kidney, heart, and small bowel was performed to assess intravascular thrombosis. RESULTS Mortality during the first hour was 50% (four of eight) in controls versus 0% with rFVIIa 720 microg/kg (p = 0.02, chi2). Blood loss was decreased in the rFVIIa 720 microg/kg group versus the placebo group (13.2 +/- 5.5 mL/kg vs. 21.9 +/- 7.7 mL/kg;p = 0.0223). Time from injury to death was significantly prolonged in the rFVIIa 720 microg/kg group compared with placebo (116 minutes vs. 8.5 +/- 3.5 minutes; p= 0.02). No macro- or microthrombi in vital organs were identified on pathologic examination.

CONCLUSION

Intravenous administration of high-dose rFVIIa early after induction of hemorrhage decreased bleeding and prolonged survival. No evidence of thrombosis in vital organs was observed.

When should a chest radiograph be obtained after chest tube removal in mechanically ventilated patients? A prospective study

BACKGROUND

The purpose of this study was to determine the appropriate time interval between the removal of a chest tube and the chest radiograph (CXR). We hypothesized that a CXR obtained 1 hour after chest tube removal would exclude the presence of a recurrent pneumothorax.

METHODS

Of 214 trauma intensive care unit patients with a chest tube during a 1-year period, 75 met entry criteria and underwent chest tube removal according to an institutional review board-approved prospective study protocol. Patients were undergoing positive-pressure ventilation, with an existing solitary chest tube, and had less than 150 mL of drainage on water seal over the previous day. After chest tube removal, serial CXRs were obtained at approximately 1, 10, and 36 hours. Demographic, chest tube, and ventilator data were collected.

RESULTS

None of the patients experienced hemodynamic or respiratory deterioration after chest tube removal. There were nine pneumothoraces (12%). All pneumothoraces were present on the initial CXR after chest tube removal. Two patients (3%) required intervention for pneumothorax. Of the remaining seven small pneumothoraces, three resolved and four were unchanged on the third CXR.

CONCLUSION

A CXR obtained within 1 to 3 hours after chest tube removal effectively identifies pneumothorax in mechanically ventilated patients.

Prospective study of the incidence and outcome of intra-abdominal hypertension and the abdominal compartment syndrome

BACKGROUND

Intra-abdominal hypertension has been recognized as a source of morbidity and mortality in the traumatized patient following laparotomy. Multiple organ dysfunction attributable to intra-abdominal hypertension has been called the abdominal compartment syndrome. The epidemiology and characteristics of these processes remain poorly defined.

METHODS

Intra-abdominal pressure was measured prospectively in all patients admitted to a trauma intensive care unit over 9 months. Data were gathered on all patients with intra-abdominal hypertension.

RESULTS

Some 706 patients were evaluated. Fifteen (2 per cent) of 706 patients had intra-abdominal hypertension. Six of the 15 patients with intra-abdominal hypertension had abdominal compartment syndrome. Half of the patients with abdominal compartment syndrome died, as did two of the remaining nine patients with intra-abdominal hypertension. Patients with abdominal compartment syndrome had a mean intra-abdominal pressure of 42 mmHg compared with 26 mmHg in patients with intra-abdominal hypertension only (P < 0.05).

CONCLUSION

The incidence of intra-abdominal hypertension and abdominal compartment syndrome was 2 and 1 per cent respectively. Intra-abdominal hypertension did not necessarily lead to abdominal compartment syndrome, and often resolved without clinical sequelae. Abdominal compartment syndrome did not occur in the absence of earlier laparotomy. Abdominal compartment syndrome was associated with a marked increase in intra-abdominal pressure (above 40 mmHg).

Early use of recombinant factor VIIa improves mean arterial pressure and may potentially decrease mortality in experimental hemorrhagic shock: a pilot study

BACKGROUND

Recombinant factor VIIa (rFVIIa) is used for treatment of bleeding episodes in hemophilia patients who develop inhibitors to factors VIII and IX. We tested the hypothesis that administration of rFVIIa early after injury would decrease bleeding and improve survival after experimental hepatic trauma.

METHODS

Anesthetized swine were cannulated for blood sampling and hemodynamic monitoring. Avulsion of left median lobe of the liver induced uncontrolled hemorrhage. After a 10% reduction of mean arterial pressure, animals were blindly randomized to receive intravenous rFVIIa (180 microg/kg) (n = 6) or placebo (n = 7).

RESULTS

Mortality was 43% (three of seven) in controls versus 0% with rFVIIa (p = 0.08, chi2). Significantly shorter prothrombin time and higher mean arterial pressures were observed in the rFVIIa group.

CONCLUSION

Intravenous administration of rFVIIa early after induction of hemorrhage shortens prothrombin time and improves mean arterial pressure. A trend toward improved survival was observed.

Unexpected findings in trauma patients dying in the intensive care unit: results of 153 consecutive autopsies

BACKGROUND

The true incidence of missed injuries in trauma-related deaths is unknown, because in only about 60% of injury-related deaths nationwide is an autopsy performed. Few studies have documented the frequency of missed diagnoses leading to deaths specifically in the trauma ICU population. We attempted to evaluate the incidence and nature of missed injuries and complications in trauma- and burn-related deaths in our ICU given an autopsy rate of close to 100%.

STUDY DESIGN

The medical records of all trauma- and burn-related deaths in the ICU over a 2-year period were reviewed retrospectively. Missed diagnoses were classified as class 1: major diagnosis that if recognized and treated appropriately might have changed outcomes; class II: major diagnosis that if recognized and treated appropriately would not have changed outcomes; and class III: minor diagnosis.

RESULTS

Complete antemortem records were available for 158 patients, of which 153 (97%) underwent autopsy. Mean age was 50 years, and 72% were males. Mean ICU stay was 10 15 days. Four (3%) patients had class I missed diagnoses: bowel infarction, meningitis, retroperitoneal abscess, and bleeding gastric ulcer. Twenty-five (16%) patients had class II diagnoses, and 12 (8%) patients had class III diagnoses. Overall, 81% of 153 patients had either class III diagnoses or no missed injuries or complications. Pneumonia was the most common missed diagnosis.

CONCLUSIONS

With an autopsy rate of 97%, 3% of deaths bad missed major diagnoses that might have affected outcomes if recognized antemortem. Autopsy findings can still provide valuable feedback in Improving the quality of care of critically ill trauma patients.

The impact of a repealed motorcycle helmet law in Miami-Dade County

OBJECTIVE

To study the impact of helmet nonuse in motorcycle crashes after the repeal of a mandatory helmet law in the state of Florida.

METHODS

We prospectively studied all patients evaluated at the University of Miami/Jackson Memorial Medical Center from July 1, 2000, through December 31, 2000, involved in motorcycle crashes, and compared them with those seen during the same time period the year before the helmet law change.

RESULTS

In 1999, before the repeal of the helmet law, there were 52 cases evaluated at our center compared with 94 after the law change. Helmet usage decreased from 1999 (83%) to 2000 (56%). The number of brain injuries (Abbreviated Injury Scale score > or = 2) during this same time period increased from 18 to 35, and the number of fatalities from 2 to 8.

CONCLUSION

The repeal of a motorcycle helmet law significantly increased the number and severity of brain injuries admitted to our trauma center.

Low-pressure laparoscopy may ameliorate intracranial hypertension and renal hypoperfusion

BACKGROUND

Increased abdominal pressure is associated with elevations in the intracranial pressure (ICP) and impaired renal function. These adverse effects are potentially important in clinical situations such as severe abdominal trauma and laparoscopic donor nephrectomy. It was hypothesized that the secondary elevation of ICP leads to release of vasoconstrictors, which may affect renal function by decreasing the renal blood flow (RBF). We investigated the effect of laparoscopy on ICP and renal blood flow in a porcine model.

MATERIALS AND METHODS

The abdominal pressure of swine (N = 5; 20-25 kg) was gradually increased from baseline to 5, 15, and 25 mm Hg by insufflation of nitrogen into the abdominal cavity. The ICP was measured using a Camino monitor, and RBF was simultaneously measured using a Transonic Doppler probe placed on the renal artery. Results were analyzed using repeated measures ANOVA and the paired t-test.

RESULTS

No significant change from baseline was observed in ICP and RBF when the abdominal pressure was 5 mm Hg. However, both ICP and RBF were affected by increasing the abdominal pressure to 15 and 25 mm Hg (P = 0.035 and 0.04 for ICP and P = 0.074 and 0.034 for RBF, respectively).

CONCLUSIONS

Low-pressure laparoscopy may reduce the adverse effects of pneumoperitoneum on ICP and RBF. It may be advisable to use low pressures in laparoscopic surgery, especially when changes in ICP or renal perfusion may have significant clinical implications.

The incision of choice for pregnant women with appendicitis is through McBurney's point

BACKGROUND

There is uncertainty over the optimal incision for gravid patients with appendicitis.

METHODS

Data were collected retrospectively from January 1, 1995, through December 31, 2000, on 374 women of childbearing age who underwent appendectomies. Of these, 23 gravid patients were evaluated.

RESULTS

Eighteen incisions were made over McBurney's point and five were created superior to McBurney's point. Patients in the third trimester of pregnancy all received incisions over McBurney's point. The appendix was located without difficulty in all 4 of the third trimester patients. The appendix was easily located in 94% of the incisions made through McBurney's point and 80% of the incisions made above McBurney's point.

CONCLUSIONS

Our clinical experience indicates that the incision for the removal of the appendix in pregnant patients in all trimesters can be successfully made over McBurney's point.

Evaluating Blunt Abdominal Trauma with Sonography: A Cost Analysis

Ultrasonography (US) is becoming increasingly utilized in the United States for the evaluation of blunt abdominal trauma (BAT). The objective of this study was to assess the cost impact of utilizing US in the evaluation of patients with BAT in a major trauma center. All patients sustaining BAT during a 6-month period before US was used at our institution (Jan–Jun 1993) were compared to BAT patients from a recent period in which US has been utilized (Jan–Jun 1995). The numbers of US, computed tomography (CT), and diagnostic peritoneal lavage (DPL) were tabulated for each group. Financial cost for each of these procedures as determined by our finance department were as follows: US $96, CT $494, DPL $137. These numbers are representative of actual hospital expenditures exclusive of physician fees as calculated in 1994 U.S. dollars. Cost analysis was performed with t test and chi squared test, and significance was defined as P < 0.05. There were 890 BAT admissions in the 1993 study period and 1033 admissions in the 1995 study period. During the 1993 period, 642 procedures were performed on the 890 patients to evaluate the

abdomen: 0 US, 466 CT, and 176 DPL (see table). This compares to 801 procedures on the 1033 patients in 1995: 552 US, 228 CT, and 21 DPL. Total cost was $254,316 for the 1993 group and $168,501 for the 1995 group. Extrapolated to a 1-year period, a significant ( P < 0.05) cost savings of $171,630 would be realized. Cost per patient evaluated was significantly reduced from $285.75 in 1993 to $163.12 in 1995 ( P < 0.05). This represents a 43 per cent reduction in per patient expenditure for evaluating the abdomen. By effectively utilizing ultrasonography in the evaluation of patients with blunt abdominal trauma, a significant cost savings can be realized. This effect results chiefly from an eight-fold reduction in the use of DPL, and a two-fold reduction in the use of CT.

Evaluating blunt abdominal trauma with sonography: a cost analysis

Ultrasonography (US) is becoming increasingly utilized in the United States for the evaluation of blunt abdominal trauma (BAT). The objective of this study was to assess the cost impact of utilizing US in the evaluation of patients with BAT in a major trauma center. All patients sustaining BAT during a 6-month period before US was used at our institution (Jan-Jun 1993) were compared to BAT patients from a recent period in which US has been utilized (Jan-Jun 1995). The numbers of US, computed tomography (CT), and diagnostic peritoneal lavage (DPL) were tabulated for each group. Financial cost for each of these procedures as determined by our finance department were as follows: US $96, CT $494, DPL $137. These numbers are representative of actual hospital expenditures exclusive of physician fees as calculated in 1994 U.S. dollars. Cost analysis was performed with t test and chi squared test, and significance was defined as P < 0.05. There were 890 BAT admissions in the 1993 study period and 1033 admissions in the 1995 study period. During the 1993 period, 642 procedures were performed on the 890 patients to evaluate the abdomen: 0 US, 466 CT, and 176 DPL (see table) [table: see text]. This compares to 801 procedures on the 1,033 patients in 1995: 552 US, 228 CT, and 21 DPL. Total cost was $254,316 for the 1993 group and $168,501 for the 1995 group. Extrapolated to a 1-year period, a significant (P < 0.05) cost savings of $171,630 would be realized. Cost per patient evaluated was significantly reduced from $285.75 in 1993 to $163.12 in 1995 (P < 0.05). This represents a 43 per cent reduction in per patient expenditure for evaluating the abdomen. By effectively utilizing ultrasonography in the evaluation of patients with blunt abdominal trauma, a significant cost savings can be realized. This effect results chiefly from an eight-fold reduction in the use of DPL, and a two-fold reduction in the use of CT.

Cost-utility of initial medical management for Crohn's disease perianal fistulae

BACKGROUND & AIMS

The cost-utility of infliximab is unknown. The aim of this study was to determine the incremental cost-utility (CU(inc)) of medical therapy for Crohn's disease (CD) perianal fistula.

METHODS

A Markov model was used to simulate a 1-year treatment period with the following: 6-mercaptopurine and metronidazole [6MP/met] (comparator), 3 infliximab infusions + 6MP/met as second-line therapy (intervention I), infliximab with episodic reinfusion (intervention II), and 6MP/met + infliximab as second-line therapy (intervention III). Utilities were elicited from patients with CD and healthy individuals by standard gamble, and costs were obtained from hospital billing data. Uncertainty was assessed by sensitivity analysis.

RESULTS

All strategies had similar effectiveness. Interventions I, II, and III were slightly more effective, but also more costly than 6MP/met (Intervention I: CU(inc) = $355,450/quality-adjusted life-years [QALY]; Intervention II: CU(inc) = $360,900/QALY; Intervention III: CU(inc) = $377,000/QALY). If the cost of infliximab were reduced to $304 per infusion, the CU(inc) for intervention II would be $54,050/QALY.

CONCLUSIONS

Based on available data, all strategies had similar effectiveness in our model, but infliximab was much more expensive than 6MP/met. The incremental benefit of infliximab for treating CD perianal fistulae over a 1-year period may not justify the higher cost. Prospective studies directly comparing 6MP/met and infliximab are warranted.

Characterization of a human plasma membrane heme transporter in intestinal and hepatocyte cell lines

Heme is the most bioavailable form of dietary iron and a component of many cellular proteins. Controversy exists as to whether heme uptake occurs via specific transport mechanisms or passive diffusion. The aims of this study were to quantify cellular heme uptake with a fluorescent heme analog and to determine whether heme uptake is mediated by a heme transporter in intestinal and hepatic cell lines. A zinc-substituted porphyrin, zinc mesoporphyrin (ZnMP), was validated as a heme homolog in uptake studies of intestinal (Caco-2, I-407) and hepatic (HepG2) cell lines. Uptake experiments to determine time dependence, heme inhibition, concentration dependence, temperature dependence, and response to the heme synthesis inhibitor succinylacetone were performed. Fluorescence microscope images were used to quantify uptake and determine the cellular localization of ZnMP; ZnMP uptake was seen in intestinal and hepatic cell lines, with cytoplasmic uptake and nuclear sparing. Uptake was dose- and temperature dependent, inhibited by heme competition, and saturated over time. Preincubation with succinylacetone augmented uptake, with an increased initial uptake rate. These findings establish a new method for quantifying heme uptake in individual cells and provide strong evidence that this uptake is a regulated, carrier-mediated process.

Splanchnic perfusion evaluation during hemorrhage and resuscitation with gastric near-infrared spectroscopy

OBJECTIVE

The purpose of this study was to use a prototype side-illuminating near-infrared spectroscopy (NIRS) nasogastric probe to continuously measure changes in gastric tissue oxygen saturation (Sto2) in a pig hemorrhage model.

METHODS

Swine (n = 12; 6 per group) underwent laparotomy and placement of a gastric NIRS probe, jejunal tonometer, superior mesenteric artery (SMA) flow probe, and a portal vein catheter. Animals underwent hemorrhage (28 mL/kg) t = 0 to 20 minutes (where t = time). Pigs in group I were resuscitated (t = 20-40 minutes) with lactated Ringer's solution (84 mL/kg), whereas group II had no resuscitation.

RESULTS

A significant decrease in mean arterial pressure and SMA flow was observed after hemorrhage. SMA flow significantly correlated in group I with both NIRS Sto2 (r = 0.58, p = 0.0001) and regional CO2 (r = -0.54, p = 0.0001). In group II, superior mesenteric flow correlated with NIRS Sto2 (r = 0.30, p = 0.03), but not regional CO2 (r = -0.23, p = 0.09).

CONCLUSION

Direct measurement of tissue oxygen saturation with a prototype side-illuminating near-infrared spectroscopy gastric probe appeared to rapidly reflect changes in splanchnic perfusion.

Hemoperitoneum score helps determine need for therapeutic laparotomy

PURPOSE

Sonography provides a fast, portable, and noninvasive method for patient assessment. However, the benefit of providing real-time ultrasound (US) imaging and fluid quantification shortly after patient arrival has not been explored. The objective of this study was to prospectively validate a US hemoperitoneum scoring system developed at our institution and determine whether sonography can predict a therapeutic operation.

METHODS

For 12 months, prospective data on all patients undergoing a trauma sonogram were recorded. All sonograms positive for free fluid were given a hemoperitoneum score. The US score was compared with initial systolic blood pressure and base deficit to assess the ability of sonography to predict a therapeutic laparotomy.

RESULTS

Forty of 46 patients (87%) with a US score > or = 3 required a therapeutic laparotomy. Forty-six of 54 patients with a US score < 3 (85%) did not need operative intervention. The sensitivity of sonography was 83% compared with 28% and 49% for systolic blood pressure and base deficit, respectively, in determining the need for therapeutic operation.

CONCLUSION

We conclude that the majority of patients with a score > or = 3 will need surgery. The US hemoperitoneum scoring system was a better predictor of a therapeutic laparotomy than initial blood pressure and/or base deficit.