Dealing with an uncooperative manager.
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Biomedical subjects
Publications and source records attributed to D B Hoyt.
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OBJECTIVE: To determine the frequency and clinical impact of transient systolic hypotension (systolic blood pressure < 100 mm Hg) in patients with severe anatomic head injury. DESIGN: Retrospective case-control study. SETTING: Urban level 1 trauma center. PATIENTS: Consecutive trauma patients admitted to the intensive care unit (ICU) with severe anatomic head injury, defined as Head and Neck Abbreviated Injury Scale Score of 4 or higher. One thousand thirteen trauma patients were admitted to the ICU during the study period, 157 of whom met inclusion criteria. MAIN OUTCOME MEASURES: Acute mortality, defined as death during initial ICU admission, and functional status of ICU survivors, assessed as level of function sufficient for discharge to home. RESULTS: One hundred fifty-seven patients with severe head injury had a total of 831 episodes of systolic hypotension. Fifty-five percent of the patients suffered at least one event. Patients were grouped by total number of low systolic blood pressure events and by average number of events per ICU day. The total number of hypotensive events was associated with increased mortality rates and decreased rate of discharge to home. Average daily frequency of events was associated with increased mortality rates. After stratification by admission Glasgow Coma Scale score, the effects were most dramatic in patients with an initial Glasgow Coma Scale score higher than 8. CONCLUSIONS: Transient hypotension is common in the ICU and is associated with increased acute mortality and decreased functional status in patients with head injury. The impact of this secondary insult is greatest in patients with less severe primary injury. Strict avoidance of hypotension through enhanced monitoring and active treatment appears to be important, especially in patients with higher presenting Glasgow Coma Scale scores.
Beat-to-beat heart rate variability (HRV) is a measure of autonomic nervous system activity, which can be quantified using frequency domain analysis. Despite its potential utility, routine serial analysis of HRV in an ICU setting has rarely been attempted. We have developed an automated system for real-time spectral analysis of HRV and have utilized this system to study the effect of alterations in HRV on mortality in a surgical ICU population. HRV measurements were performed every 6 hr on all patients in the ICU. Total spectral power in the variability signal (TP, a measure of overall autonomic activity) and the ratio of high frequency to low frequency components (HF/LF ratio, a measure of parasympathetic/sympathetic balance) were calculated. Over a 6-month period 7994 automated HRV measurements were made in 742 patients. Both low TP (low autonomic tone) and high HF/LF ratio (relative lack of sympathetic tone) were associated with increased mortality. A low HF/LF ratio (relatively high sympathetic tone) was associated with increased survival, especially in patients with low autonomic tone. We conclude that serial spectral analysis of HRV is practical in an ICU setting and that HRV parameters appear to be a clinically relevant indication of autonomic activity. Low sympathetic tone and vagal predominance are associated with increased mortality, while sympathetic predominance favors survival. Monitoring of HRV parameters has the potential to detect physiologic deterioration or response to therapy.
It was previously shown that hypertonic saline (HTS) enhances in vivo and in vitro cellular immune function of normal mice and reverses in vitro prostaglandin E2 (PGE2)-induced immunosuppression of normal peripheral blood mononuclear cells. Hemorrhage induces immunosuppression despite adequate isotonic fluid resuscitation. The effects of HTS resuscitation on immunosuppression following hemorrhage were studied. A mouse model of hemorrhagic shock was used. Bleeding was performed through a catheter placed in the femoral artery. Phytohemagglutinin-induced splenocyte proliferation and interleukin (IL)-1, IL-2,IL-4, IL-6, IL-10, transforming growth factor beta, and PGE2 plasma levels were measured 2 and 24 hr following hemorrhage and resuscitation with lactated Ringer's and HTS. In vivo cellular immune function was measured using a contact hypersensitivity test. Suppression of splenocyte proliferation (40%) 24 hr following hemorrhage occurred after lactated Ringer's resuscitation. HTS prevented immunosuppression. In vivo cell-mediated immune function 24 hr after hemorrhage was improved by HTS. HTS-resuscitated animals showed significantly lower levels of IL-4 and PGE2, and slightly elevated levels of proinflammatory cytokines (IL-1, IL-2, and IL-6). HTS reverses hemorrhage-induced T-cell suppression by reducing the production and/or release of IL-4 and PGE2.
HYPOTHESIS: Emergency cesarean sections in trauma patients are not justified and should be abandoned. SETTING AND DESIGN: A multi-institutional, retrospective cohort study was conducted of level 1 trauma centers. METHODS: Trauma admissions from nine level 1 trauma centers from January 1986 through December 1994 were reviewed. Pregnant women who underwent emergency cesarean sections were identified. Demographic and clinical data were obtained on all patients undergoing a cesarean section. Fetal distress was defined by bradycardia, deceleration, or lack of fetal heart tones (FHTs). Maternal distress was defined by shock (systolic blood pressure < 90) or acute decompensation. Statistical analyses were performed. RESULTS: Of the 114,952 consecutive trauma admissions, more than 441 pregnant women required 32 emergency cesarean sections. All were performed for fetal distress, maternal distress, or both. Overall, 15 (45%) of the fetuses and 23 (72%) of the mothers survived. Of 33 fetuses delivered, 13 had no FHTs and none survived. Twenty infants (potential survivors) had FHTs and an estimated gestational age (EGA) of greater than or equal to 26 weeks, and 75% survived. Infant survival was independent of maternal distress or maternal Injury Severity Score. The five infant deaths in the group of potential survivors resulted from delayed recognition of fetal distress, and 60% of these deaths were in mothers with mild to moderate injuries (Injury Severity Score < 16). CONCLUSIONS: In pregnant trauma patients, infant viability is defined by the presence of FHTs, estimated gestational age greater than or equal to 26 weeks. In viable infants, survival after emergency cesarean section is acceptable (75%). Infant survival is independent of maternal distress or Injury Severity Score. Sixty percent of infant deaths resulted from delay in recognition of fetal distress and cesarean section. These were potentially preventable. Given the definition of fetal viability, our initial hypothesis is invalid.
OBJECTIVE: In 1986, data from 25,000 major trauma outcome study patients were used to relate Trauma and Injury Severity Score (TRISS) values to survival probability. The resulting norms have been widely used. Motivated by TRISS limitations, A Severity Characterization of Trauma (ASCOT) was introduced in 1990. The objective of this study was to evaluate and compare TRISS and ASCOT probability predictions using carefully collected and independently reviewed data not used in the development of those norms. DESIGN: This was a prospective data collection for consecutive admissions to four level I trauma centers participating in a major trauma outcome study. MATERIALS AND METHODS: Data from 14,296 patients admitted to the four study sites between October 1987 through 1989 were used. The indices were evaluated using measures of discrimination (disparity, sensitivity, specificity, misclassification rate, and area under the receiver-operating characteristic curve) and calibration [Hosmer-Lemeshow goodness-of-fit statistic (H-L)]. MEASUREMENTS AND MAIN RESULTS: For blunt-injured adults, ASCOT has higher sensitivity than TRISS (69.3 vs. 64.3) and meets the criterion for model calibration (H-L statistic < 15.5) needed for accurate z and W scores. The TRISS does not meet the calibration criterion (H-L = 30.7). For adults with penetrating injury, ASCOT has a substantially lower H-L value than TRISS (20.3 vs. 138.4), but neither meets the criterion. Areas under TRISS and ASCOT ROC curves are not significantly different and exceed 0.91 for blunt-injured adults and 0.95 for adults with penetrating injury. For pediatric patients, TRISS and ASCOT sensitivities (near 77%) and areas under receiver-operating characteristic curves (both exceed 0.96) are comparable, and both models satisfy the H-L criterion. CONCLUSIONS: In this age of health care decisions influenced by outcome evaluations, ASCOT's more precise description of anatomic injury and its improved calibration with actual outcomes argue for its adoption as the standard method for outcome prediction.
OBJECTIVES: Endotoxin induced suppression of cellular immune function is thought to contribute to septic complications in trauma patients. A rabbit model of endotoxemia was used to determine the relative roles of the anti-inflammatory factors interleukin-4 (IL-4), interleukin-10 (IL-10), transforming growth factor beta1 (TGFbeta1), and prostaglandin E2 (PGE2) in addition to other factors, in inducing immunosuppression. DESIGN: T-cell suppressive factors (TSF) in serum ultrafiltrates were separated and tested for the presence of the known suppressive factors PGE2, IL-4, IL-10, and TGFbeta1. MATERIAL AND METHODS: New Zealand rabbits were injected with 50 microg/kg of purified Escherichia coli lipopolysaccharide. Animals were exsanguinated after 48 hours and serum was separated by ultrafiltration (cutoff 50 kd), TSK HW-40 size exclusion chromatography, and Q-Sepharose anion exchange chromatography. TSF activities of chromatographic fractions and serum samples were measured with a mitogen induced in vitro T-cell proliferation assay. Levels of PGE2, IL-4, IL-10, and TGFbeta1 were measured with enzyme immunoassays. MEASUREMENTS AND MAIN RESULTS: Serum TSF activity, and levels of PGE2, IL-4, IL-10, and TGFbeta1 were increased after endotoxemia. Size exclusion chromatography revealed three major fractions (TSF1-3) with up to 600 times more TSF activity compared with controls. IL-4 and IL-10 were found in TSF1 and TSF3. Further separation of TSF1 by anion exchange chromatography revealed a total of eight different T-cell suppressive factors. TGFbeta1 probably remained in the retentate after ultrafiltration, while PGE2 eluted at a higher retention time. The known anti-inflammatory factors TGFbeta1, IL-10, IL-4, and PGE2 only accounted for 13% of the total serum TSF activity of 614 U/mL. CONCLUSIONS: Lipopolysaccharide shock results in the release of multiple T-cell suppressive factors in addition to known immunosuppressive factors, all of which contribute to the anti-inflammatory response.
OBJECTIVE: The purpose of this study is to evaluate the utility and feasibility of abdominal ultrasound (US) in blunt trauma patients. DESIGN: This prospective study examined the operational issues and the diagnostic accuracy of US in selected blunt trauma patients triaged to a Level 1 trauma center. MATERIALS AND METHODS: All patients were evaluated by an attending trauma surgeon and our usual criteria for objective evaluation of the abdomen were applied. US was performed by US technicians and interpreted by the trauma surgeon. We prospectively evaluated the availability (time to arrival), the ease with which the US could be integrated into the resuscitation (minutes to start after arrival), and the time required to perform the study. The US results were compared to diagnostic peritoneal lavage and computed tomography findings, clinical course, operative findings, and to repeat US examinations to determine sensitivity, specificity, and usefulness. MEASUREMENTS AND MAIN RESULTS: A total of 800 US studies were performed over 15 months. In four cases (0.5%), the US was incomplete for technical reasons. The results in the remaining 796 studies were as follows: [table: see text] The average time to arrival of the US was 17.3 minutes (range 0-120) and the average minutes to start after arrival was 7.0 (range 1-49). The average time required to perform the study was 10.6 minutes (range 2-26). CONCLUSIONS: This study demonstrates that US can be obtained rapidly, integrated into the resuscitation, and completed quickly. US provides a highly accurate, noninvasive method to evaluate the abdomen in the blunt trauma patient, and has supplanted the previously used methods at this institution.
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UNLABELLED: Severe injury is frequently complicated by sepsis and organ failure. Activated neutrophils adherent to inflamed endothelia have been implicated in the pathogenesis of these complications. Identification of high-risk patients to target immunomodulatory therapy, however, remains an elusive goal. We postulated that (1) patients at risk for sepsis and organ failure could be identified by measuring shed selectin adhesions molecules as a marker of endothelial activation after injury and reperfusion, and (2) these elevated selectin levels would correlate with injury severity, shock, major complications, and mortality. METHODS: Blood samples were drawn from 50 patients with multiple trauma every 2 hours after admission for the first 24 hours, and every 6 hours for the subsequent 24 hours, and assayed for levels of shed E- and P-selectin. Patients were then stratified according to Injury Severity Score (ISS), presence or absence of shock, presence or absence of organ failure and/or infectious complications, and finally, death versus survival. RESULTS: Trauma patients who had ISS < 30, who did not develop shock, sepsis, or organ dysfunction, had minimal increase in circulating E- and P-selectin over admission levels. In patients who subsequently developed infectious complications, organ dysfunction, or both, or subsequently went on to die, elevated levels of E-selectin levels were evident by 36 hours, and in some cases, earlier. Differences between nonsurvivors and survivors was statistically significant. There was also a trend toward increased levels of P-selectin in the same group of patients, although these differences were not significant. There was no differentiation in either of the two selections when patients were stratified according to ISS or presence of shock. CONCLUSION: A subset of major trauma patients manifest increased levels of circulating E-selectin adhesion molecules after resuscitation. These patients seem to be at increased risk of death and possibly at risk for infections complications and organ failure. Selectin blockade is a potential new immunomodulatory strategy in this subgroup of patients.
Endotoxemia initiates a cytokine response that is thought to mediate the syndromes of sepsis and multiple organ failure. This study measured cytokine levels in the blood and airways of rats at critical time points during the development of lung injury induced by chronic endotoxin (LPS) infusion in the rat. Tumor necrosis factor-alpha (TNF), interleukin-1-beta (IL-1), and interleukin-6 (IL-6) were measured in the blood and bronchoalveolar lavage fluid (BALF) of endotoxemic and control animals. BALF was also studied for the percentage of neutrophil (PMN) count and chemotactic activity. Lung histology was determined at 72 h following infusion of LPS. Chronic endotoxemia of > or = 48 h but not < or = 24 h resulted in severe acute lung injury (ALI). Circulating levels of TNF and IL-1 were only transiently elevated, whereas IL-6 remained elevated in the endotoxemic rats. TNF, IL-1, and IL-6 levels in BALF were only transiently elevated. Chemotactic activity, levels of cytokine-induced neutrophil chemoattractant (CINC), and the percentage of PMN counts in BALF all increased significantly by 36 h. Other potential chemoattractants; leukotriene B4 and transforming growth factor-beta were not elevated in BALF. In conclusion, severe ALI requires a minimum of 48 h LPS infusion in this model and is associated with high levels of circulating IL-6, increased CINC activity, and an increased percentage of PMN count in BALF. Local inflammatory events may be as important as the systemic cytokine milieu in mediating ALI. The signal for these local events does not appear to depend solely on the transient elevations of circulating TNF and IL-1 at the onset of endotoxemia, although sustained high levels of IL-6 may be important.
OBJECTIVE: To determine if high-risk behavior is associated with increased injury severity and cost and if public agencies bear a disproportionate burden of that cost. DESIGN: Case comparison study utilizing patient data collected over a 10-year period. SETTING: Five level 1 and 2 trauma centers in an urban-suburban community with a population of 2.4 million. PARTICIPANTS: Trauma registry data from 37,304 consecutive hospitalized adult patients with trauma. Financial data were reported and analyzed on 28,842 of these. MAIN OUTCOME MEASURES: Incidence of alcohol intoxication, other drug use, use of vehicular protective devices, and firearm violence injuries in patients with private vs public health care sponsorship. Length of hospital stay, injury severity, and hospital unit charges were assessed for high-risk behavior. RESULTS: High-risk behavior was more prevalent among trauma patients relying on public funding to cover the costs of their injuries (P < .001). Total hospital unit charges were 28% and 35% higher for motorists not wearing seat belts and motorcyclists not wearing helmets, respectively. Injury severity and length of stay were also higher (P < .001). CONCLUSIONS: High-risk behavior is associated with increased injury severity and cost. Trauma victims exhibiting high-risk behavior more often depend on public agencies to cover the cost of acute injury. Failure to establish and enforce laws and policies designed to reduce or prevent injury may generate enormous trauma care costs, borne to a large extent by public agencies. Further restriction of certain types of high-risk behavior and the institution of "users' fees," taxes, or penalties may be necessary to reduce the disproportionate public agency cost generated by this activity.
BACKGROUND: A growing concern among university surgeons is a perceived threat to the traditional academician role. Factors that have led to this concern include (1) changes in reimbursement and patient referral patterns, both of which have resulted in reduced income; (2) mounting external pressure from the departmental chairperson/dean to generate professional fees; (3) pervasive ambiguity in the criteria for promotion and tenure; (4) intensified competition for research dollars in recent years; and (5) a perception that fellow academicians view surgeons as operating room technicians incapable of laboratory research. These cogent issues have the means to place academic goals in jeopardy. Potentially they lead to dissatisfaction, unhappiness, and eventual departure from academia. A healthy solution to the problem includes departmental recognition and reward for whichever primary role/s the academic surgeon embraces--clinical, educational, research, or administrative. Clear chairperson-faculty communication on the issues of expectation and reward is a key ingredient in the solution. METHODS: A mail survey was conducted with chairpersons of surgical departments and academic surgeons addressing the issues of retention, promotion, and benefits. RESULTS: Results revealed significant differences in perceptions, suggesting the need for improved communication between faculty and chairpersons and a team approach to help maintain academic viability in the future. CONCLUSIONS: When the quadruple threat can be mutually described as a departmental rather than individual quality, the joys and rewards of academic surgery can be considerable for faculty and chairpersons alike.
STUDY OBJECTIVE: To identify patients presenting with hypotension due to blunt trauma who should undergo computed tomography (CT) of the head before urgent chest or abdominal operation. DESIGN: Retrospective registry-based record review. SETTING: Urban Level I trauma center. PARTICIPANTS: Consecutive trauma patients with suspected head injury, blunt mechanism of injury, and hypotension who were discharged between January 1, 1989, and December 31, 1991. Patients who were dead on arrival or died within 15 minutes of arrival were judged unsalvageable and excluded. Review of 3,224 trauma patients identified 212 as the study population. INTERVENTIONS: Frequency of neurosurgical intervention or general surgical intervention within 6 hours of admission and the time required for completion of CT of the head were noted. RESULTS: Overall, 40 general surgical operations (19%) and 16 craniotomies (8%) were performed, with a mortality rate of 18%. Patients with Glasgow Coma Scale scores of less than 8 had a 19% rate of craniotomy, and those with scores between 8 and 13 had a 9% rate. Sixteen patients had CT before surgery, with an average delay of 68 minutes. No patient who responded to initial resuscitation experienced hemodynamic instability in the CT suite, including 15 patients with positive diagnostic peritoneal lavage. CONCLUSION: CT scan of the head before general surgical operation appears to be safe in patients who respond to initial resuscitation. The likelihood of craniotomy in patients with Glasgow Coma Scale scores of 13 or less is comparable to the likelihood of general surgical operation. Physicians should be encouraged to make CT of the head a high priority in this group.
OBJECTIVE: To determine if early enteral feeding, in an intensive care unit (ICU) patient population, using a formula supplemented with arginine, dietary nucleotides, and fish oil (Impact), results in a shorter hospital stay and a reduced frequency of infectious complications, when compared with feeding a common use enteral formula (Osmolite.HN). DESIGN: A prospective, randomized, double-blind, multicenter trial. SETTING: ICUs in eight different hospitals. PATIENTS: Of 326 patients enrolled in the study, 296 patients were eligible for analysis. They were admitted to the ICU after an event such as trauma, surgery, or sepsis, and met a risk assessment screen (Acute Physiology and Chronic Health Evaluation II [APACHE II] score of > or = 10, or a Therapeutic Intervention Scoring System score of > or = 20) and study eligibility requirements. Patients were stratified by age (< 60 or > or = 60 yrs of age) and disease (septic or systemic inflammatory response syndrome). INTERVENTIONS: Patients were enrolled and full-strength tube feedings were initiated within 48 hrs of the study entry event. Enteral feedings were advanced to a target volume of 60 mL/hr by 96 hrs of the event. One hundred sixty-eight patients were randomized to receive the experimental formula, and 158 patients were randomized to receive the common use control formula. MEASUREMENTS AND MAIN RESULTS: Both groups tolerated early enteral feeding well, and the frequency of tube feeding-related complications was low. There were no significant differences in nitrogen balance between groups on study days 4 and 7. Patients receiving the experimental formula had a significant (p = .0001) increase in plasma arginine and ornithine concentrations by study day 7. Plasma fatty acid profiles demonstrated higher concentrations of linoleic acid (p < .01) in the patients receiving the common use formula and higher concentrations of eicosapentaenoic and docosahexaenoic acid (p < .01) in the patients receiving the experimental formula. The mortality rate was not different between the groups and was significantly (p < .001) lower than predicted by the admission severity scores in both feeding groups. In patients who received at least 821 mL/day of the experimental formula, the hospital median length of stay was reduced by 8 days (p < .05). In patients stratified as septic, the median length of hospital stay was reduced by 10 days (p < .05), along with a major reduction in the frequency of acquired infections (p < .01) in the patients who received the experimental formula. In the septic subgroup fed at least 821 mL/day, the median length of stay was reduced by 11.5 days, along with a major reduction in acquired infections (both p < .05) in the patients who received the experimental formula. CONCLUSIONS: Early enteral feeding of the experimental formula was safe and well tolerated in ICU patients. In patients who received the experimental formula, particularly if they were septic on admission to the study, a substantial reduction in hospital length of stay was observed, along with a significant reduction in the frequency of acquired infections.
Prophylaxis for stress ulceration is considered standard care for most critically ill patients, but may be overutilized. We determined the incidence of stress ulceration in 33,637 major trauma patients treated in a regionalized trauma system from 1985 to 1991 using trauma registry data and chart review. Injury-related risk factors for stress ulceration and other associated infectious and organ failure complications were identified by regression analysis. Clinical stress ulceration developed in 57 patients (0.17%) despite prophylaxis. Eighteen patients (0.05%) developed severe ulceration with either gastroduodenal perforation (3 patients) or a > 2 U blood transfusion requirement (16 patients). Independent risk factors with odds ratios (OR) were identified as follows: Injury Severity Score (ISS) > or = 16, OR = 12.6; spinal cord injury, OR = 2.0; and age > 55, OR = 2.4. Other serious complications, including pneumonia, sepsis, and organ failure (adult respiratory distress syndrome and renal and hepatic failure), were significantly associated with the development of stress ulceration. Clinically significant stress ulceration after trauma is uncommon, but occurs despite prophylaxis. Severe injury (ISS > 16) and spinal cord injury were identified as independent injury-related risk factors. All patients with severe ulceration had either one of these injury-related risk factors or a significant infectious complication or organ failure. Standard prophylaxis may be inadequate in high-risk patients, who should be targeted for increased surveillance and aggressive prophylaxis. On the other hand, routine prophylaxis in low-risk patients may be overutilized.
OBJECTIVE: Injuries to the portal triad are a rare and complex challenge in trauma surgery. The purpose of this review is to better characterize the incidence, lethality, and successful management schemes used to treat these injuries. DESIGN: A retrospective review of the experience of eight academic level I trauma centers over a combined 62 years. RESULTS: A retrospective review of the experience of eight anatomical structures of the portal hepatis: 118 injuries to the anatomical structures of the portal hepatis: 55 extrahepatic portal vein injuries, 28 extrahepatic arterial injuries, and 35 injuries to the extrahepatic biliary tree. Sixty-nine percent of the injuries were by penetrating mechanism and 31% were by blunt mechanism. All patients had associated injuries with a mean Injury Severity Score of 34 in blunt trauma patients. Overall mortality was 51%, rising to 80% in patients with combination injuries. Sixty-six percent of deaths occurred in the operating room, primarily from exsanguination; 18% of deaths occurred within 48 hours of injury from refractory shock, coagulopathy, or cardiac arrest; 16% occurred late. Ten percent of patients undergoing portal vein ligation survived, compared to 58% managed by primary repair. Survival after hepatic artery ligation was 42%, compared to 14% after primary repair. Survival after biliary-enteric anastomosis as treatment of extrahepatic bile duct injury was 89%, compared to 50% after primary repair and 100% after ligation of lobar bile duct injuries. Missed bile duct injuries had a high (75%) severe complication rate. CONCLUSIONS: Injuries to the anatomical structures of the portal triad are rare and often lethal. Intraoperative exsanguination is the primary cause of death, and hemorrhage control should be the first priority. Bile duct injuries should be identified by intraoperative cholangiography and repaired primarily or by enteric anastomosis; lobar bile ducts can be managed by ligation.