Arthur W. Fleming

Comparison of measurements of cardiac output by bioimpedance and thermodilution in severely ill surgical patients

In order to evaluate a new thoracic electrical bioimpedance (TEB) system for measurement of stroke volume based on the Sramek-Bernstein equation, 391 paired values of cardiac output were measured simultaneously with the standard thermodilution method. These values were obtained from 16 patients selected for having the most severe illness during a 6-month period; the intent was to evaluate the bioimpedance method in the worst possible situations. The correlation coefficient (r) was 0.83, slope was 0.87, intercept was 1.53, and the mean difference between the two methods was 16.2 ± 11.8 (SD)% in the total series. In 285 paired samples where satisfactory conditions were met, r was 0.90, slope was 0.98, intercept was 0.34, and the mean difference was 11.8 ± 8.9%. The data indicate satisfactory correlations between these two methods. When the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreement between serial thermodilution methods. Difficulties may arise with dysrhythmias, tachycardia (heart rate greater than 150 beat/min), metal in the chest or chest wall, sepsis, hypertension, and extremely oily skin. Mechanical ventilation did not appear to be a problem.

Multiple organ failure: By the time you predict it, it's already there

OBJECTIVE Validate an at-risk population to study multiple organ failure and to determine the importance of organ dysfunction 24 hours after injury in determining the ultimate severity of multiple organ failure. METHODS We evaluated 105 patients admitted to five academic trauma centers during a 1-year period who survived for more than 24 hours with Injury Severity Scores > or = 25 and who received 6 or more units of blood. Organ dysfunction was scored daily with a modified multiple organ failure scoring system made up of individual adult respiratory distress syndrome score, renal dysfunction, hepatic dysfunction, and cardiac dysfunction scores. Multiple organ failure (MOF) severity was quantitated using the maximum daily multiple organ failure score and the cumulative sum of daily multiple organ failure scores for the first 7 days (MOF 7) and 10 days (MOF 10). Independent variables included markers of tissue injury, shock, host factors, physiologic response, therapeutic factors, and organ dysfunction within the first 24 hours after admission. Data were subjected to a conditional stepwise multiple regression analysis, first excluding and then including 24-hour MOF as an independent variable. RESULTS Of the 105 high-risk patients, 69 (66%) developed a maximum daily multiple organ failure score > or = 1; 50 (72%) did so on day 1 one and 60 (87%) did so by day 2. In multiple regression models, the multiple correlation coefficient increased from 0.537 to 0.720 when maximum MOF was the dependent variable, from 0.449 to 0.719 when maximum daily MOF was the dependent variable, from 0.519 to 0.812 when MOF 7 was the dependent variable, and from 0.514 to 0.759 when MOF 10 was the dependent variable. CONCLUSION We have confirmed that the population of patients with Injury Severity Scores > or = 25 who received 6 or more units of blood represent a high-risk group for the development of multiple organ failure. Our data also indicate that multiple organ failure after trauma is established within 24 hours of injury in the majority of patients who develop it. It appears that multiple organ failure is already present at the time when most published models are trying to predict whether or not it will occur.

Initial and Long-term Results in the Management of Primary Chest Wall Neoplasms

One hundred ten patients with primary chest wall neoplasms were analyzed for long-term results. The diagnosis of 59 malignant and 51 benign tumors was confirmed by the Armed Forces Institute of Pathology. No deaths were associated with primary definitive therapy. Among the five most frequently encountered malignant tumor types, five-year survivals were obtained in 9 of 17 (53%) patients with fibrosarcoma, 8 of 9 (89%) patients with chondrosarcoma, 2 of 8 (25%) patients with solitary chest wall plasmacytoma (multiple myeloma), 1 of 6 (17%) patients with Ewings sarcoma, and 2 of 4 (50%) of patients with osteogenic sarcoma. Although the five-year survival appears to indicate therapeutic success in patients with Ewings sarcoma and osteogenic sarcoma, patients with chondrosarcoma or fibrosarcoma may have a more protracted course, and those with solitary plasmacytoma usually develop multiple myeloma. The findings suggest that radical surgical excision is the treatment of choice for chondrosarcoma; radical surgical excision combined with chemotherapy, for fibrosarcoma and osteogenic sarcoma; surgical excision combined with radiation and chemotherapy, for Ewings sarcoma; and systemic surveillance and therapy, for pathologically confirmed solitary plasmacytoma.

Patient volume per surgeon does not predict survival in adult level I trauma centers.

BACKGROUND The 1999 American College of Surgeons resources for optimal care document added the requirement that Level I trauma centers admit over 240 patients with Injury Severity Score (ISS) > 15 per year or that trauma surgeons care for at least 35 patients per year. The purpose of this study was to test the hypothesis that high volume of patients with ISS > 15 per individual trauma surgeon is associated with improved outcome. METHODS Data were obtained from the trauma registry of the five American College of Surgeons-verified adult Level I trauma centers in our mature trauma system between January 1, 1998, and March 31, 1999. Data abstracted included age, sex, Glasgow Coma Scale (GCS) score, intensive care unit length of stay, hospital length of stay, probability of survival (Ps), mechanism of injury, number of patients per each trauma surgeon and institution, and mortality. Multiple logistic regression was performed to select independent variables for modeling of survival. RESULTS From the five Level I centers there were 11,932 trauma patients in this time interval; of these, 1,754 patients (14.7%) with ISS > 15 were identified and used for analysis. Patients with ISS > 15 varied from 173 to 625 per institution; trauma surgeons varied from 8 to 25 per institution; per-surgeon patient volume varied from 0.8 to 96 per year. Logistic regression analysis revealed that the best independent predictors of survival were Ps, GCS score, age, mechanism of injury, and institutional volume (p < 0.01). Age and institutional volume correlated negatively with survival. Analysis of per-surgeon patient caseload added no additional predictive value (p = 0.44). CONCLUSION The significant independent predictors of survival in severely injured trauma patients are Ps, GCS score, age, mechanism of injury, and institutional volume. We found no statistically meaningful contribution to the prediction of survival on the basis of per-surgeon patient volume. Since this volume criterion for surgeon enpanelment and trauma center designation would not be expected to improve outcome, such a requirement should be justified by other measures or abandoned.

The Glasgow Coma Scale and Prognosis in Gunshot Wounds to the Brain

To determine which factors predict survival in patients with gunshot wounds to the brain, 192 patients who had intracranial injury demonstrated on computed tomographic (CT) scanning were retrospectively reviewed. Glasgow Coma Scale (GCS) scores on admission seemed to be the most important factor in predicting survival. Age, the presence of extruded brain, and use of a shotgun could not be shown to be factors independent of admission GCS score. Findings on CT scans (single lobe vs. multilobe involvement) helped to predict survival only in patients with GCS scores 5-13. The mortality rate was 35%. Among survivors 18% had brain-related long-term disability, and an additional 27% had long-term disability related to associated eye injury.

Use of fibrin glue in hepatic trauma.

We evaluated the efficacy and safety of fibrin glue (FG) made with highly concentrated human fibrinogen and clotting factors in achieving hemostasis of superficial and deep hepatic injuries. Experimentally produced hepatic injuries were produced in 12 adult mongrel dogs and hemostatically sealed with FG. Half of the dogs each received two penetrating hepatic injuries consisting of a large laceration and a deep stab wound through the liver; the remaining dogs underwent resection of a large segment of the left lobe of the liver. Hemostasis was achieved by applying FG into and over the bleeding wounds; hepatic arterial occlusion was not used. Complete hemostasis was achieved in all animals before skin closure. One dog from each group was re-explored and the liver specimens harvested for gross and microscopic examination at postoperative intervals of 12 hours, 24 hours, and 2, 3, 6, and 8 weeks. There were no cases of intra-abdominal infection, abscess formation, or bile fistulae. Histologic examination demonstrated a thickened capsule containing fibrous connective tissue and neovascular proliferation; there were no signs of local or systemic toxicity. One dog died on postoperative day 1 from rebleeding from the hepatic injury; all other dogs survived without complications. We conclude that FG provides effective hemostasis of superficial and deep hepatic injuries, and has good systemic and local compatibility. Its use in surgery for hepatic trauma may lead to less intraoperative blood loss and transfusion requirements, as well as a reduced need for major hepatic resection to control hemorrhage.

Factors affecting outcome in pancreatic trauma.

Reported mortality from pancreatic trauma remains at approximately 20% and morbidity is about 33%. A recent series was reviewed to highlight unresolved problems associated with this injury. From 54 consecutive patients treated operatively for pancreatic trauma during a recent 7-year period, 44 patients were evaluated. Among these 44, six died and 12 developed fistulas and/or abscesses. Of those who died, four had colon injuries and two had duodenal injuries, one of whom had combined colon and duodenal injuries. Patients with colon injuries also had a higher incidence of intra-abdominal abscesses and fistulas. Indeed, colon injury currently may be the most significant factor causing morbidity and mortality in cases of pancreatic trauma. Despite improved management of duodenal injuries, morbidity and mortality rates for these patients also remain high. Twenty-six patients went into shock before the end of their operation, and all six deaths occurred in this group. The mean number of intra-abdominal associated organ injuries was 2.1 per patient; complications and deaths were directly related to these injuries.

Continuous use of standard process audit filters has limited value in an established trauma system.

OBJECTIVE To evaluate the ability of five quality assurance/ quality improvement audit filters to identify opportunities for improvement in patient care in a mature trauma system. DESIGN Retrospective analysis of prospectively collected data. MATERIALS AND METHODS Total patient population at risk and audit filter fallouts were evaluated for the following audit filters: patients with (1) Glasgow Coma Scale (GCS) score < 14 who did not receive a CT scan within 2 hours of admission; (2) subdural/ epidural hematomas who did not undergo craniotomy within 4 hours; (3) open tibial fractures who did not undergo debridement within 8 hours; (4) abdominal gunshot wounds who did not undergo laparotomy within 4 hours; and (5) all deaths where a quality assurance action was taken. The filters were used for 1 year. Mortality was compared between fallouts and nonfallouts in each category and the frequency of corrective actions for each category were determined. RESULTS Corrective actions were taken in 97 of the 418 fallouts from 3,787 patients at risk. The majority (77%) of these actions were for patients in the death audit filter group. There were 343 nondeath fallouts, representing 13% of the 2,719 nondeath patients at risk. Of these, 22 corrective actions were taken, representing 6.4% of the fallouts and less than 1% of the patients at risk. CONCLUSION The non-death process based audit filters that we evaluated in our trauma system documented adherence to care process standards but found few opportunities for quality improvement, suggesting that audit filters should be periodically evaluated and changed when their goals have been accomplished.

Development and testing of a decision tree for blunt trauma.

The aim of the present study was to examine the essential problems in a retrospective study of 381 organ injuries in 260 patients, to identify problems, to define criteria, to describe decision rules, and to organize these rules into branch-chain decision trees or clinical algorithms. The basic hypothesis of this study is that criteria organized into a prioritized decision tree can provide objective standards to evaluate the quality of trauma care and to compare alternative approaches. The algorithm was designed to provide prompt therapy for the most life-threatening problems: respiratory and cardiac arrest, shock, head injury, tamponade, lacerations of the great vessels, cardiac contusion, ruptured parenchymal organs, lacerated viscera, and injury to other intraperitoneal organs. Resuscitation from shock, correction of circulatory problems, and monitoring of physiologic variables were prioritized to evaluate the presence of circulatory deficits and the adequacy of specific therapy to correct them. Concomitantly, diagnosis of the underlying problems was approached using peritoneal lavage, abdominal and chest x-rays, iv urograms, cystograms, endoscopy, upper and lower GI barium or hypaque studies, ultrasound, scintograms, and CT scans. In emergency conditions these are limited to a large extent by time factors. The diagnostic accuracy, priorities, and limitations of each of these were evaluated in emergency conditions. The algorithm was used to track management decisions in a prospective series; the mortality of 51 patients with satisfactory compliance was 4% and 44% in nine patients with major deviations from the algorithm.

Transcutaneous oxygen recovery and toe pulse reappearance time in the assessment of peripheral vascular disease.

The accuracy of measurements of transcutaneous oxygen tension (Ptco2) in the diagnosis of peripheral vascular disease (PVD) may be significantly increased by stressing limb circulation with the use of temporary ischemia. The purpose of this study was to compare the transcutaneous oxygen recovery half-time (TORT) and the toe pulse reappearance time (PRT/2) in a series of patients with symptomatic PVD before and after vascular reconstruction. The TORT was defined as the time required to recover half of the decrease in the limb/chest Ptco2 ratio caused by temporary limb ischemia, and is conceptually comparable to the toe PRT/2, the time required to recover half of the control toe pulse amplitude. Measurement of TORT was found to be more feasible (100% vs 58%) and to have a greater diagnostic yield (100% vs 92%) than that of the toe PRT/2. When measured on the dorsum of the foot, TORT values were found to correlate well with the severity of symptoms of PVD; toe PRT/2 values did not correlate with severity of symptoms. Patients who underwent successful vascular reconstruction had significant improvement in their calf and foot TORT values after surgery (p less than .005 and .0005, respectively); postoperative values were similar to those obtained in normal subjects. Toe PRT/2 values usually improved postoperatively, but in many patients postoperative values overlapped with values that were considered abnormal. There was no overlap of TORT values in normal subjects with those in patients with symptomatic PVD. The measurement of TORT may be clinically useful for screening patients with suspected PVD and for assessing quantitatively the results of conservative and surgical therapy.(ABSTRACT TRUNCATED AT 250 WORDS)