The first 72 hours of brain tissue oxygenation predicts patient survival with traumatic brain injury.

BACKGROUND: Utilization of brain tissue oxygenation (pBtO(2)) is an important but controversial variable in the treatment of traumatic brain injury. We hypothesize that pBtO(2) values over the first 72 hours of monitoring are predictive of mortality. METHODS: Consecutive, adult patients with severe traumatic brain injury and pBtO(2) monitors were retrospectively identified. Time-indexed measurements of pBtO(2), cerebral perfusion pressure (CPP), and intracranial pressure (ICP) were collected, and average values over 4-hour blocks were determined. Patients were stratified according to survival, and repeated measures analysis of variance was used to compare pBtO(2), CPP, and ICP. The pBtO(2) threshold most predictive for survival was determined. RESULTS: There were 8,759 time-indexed data points in 32 patients. The mean age was 39 years ± 16.5 years, injury severity score was 27.7 ± 10.7, and Glasgow Coma Scale score was 6.6 ± 3.4. Survival was 68%. Survivors consistently demonstrated higher pBtO(2) values compared with nonsurvivors including age as a covariate (F = 12.898, p < 0.001). Individual pBtO(2) was higher at the time points 8 hours, 12 hours, 20 hours to 44 hours, 52 hours to 60 hours, and 72 hours of monitoring (p < 0.05). There was no difference in ICP (F = 1.690, p = 0.204) and CPP (F = 0.764, p = 0.389) values between survivors and nonsurvivors including age as a covariate. Classification and regression tree analysis identified 29 mm Hg as the threshold at which pBtO(2) was most predictive for mortality. CONCLUSION: The first 72 hours of pBtO(2) neurologic monitoring predicts mortality. When the pBtO(2) monitor remains below 29 mm Hg in the first 72 hours of monitoring, mortality is increased. This study challenges the brain oxygenation threshold of 20 mm Hg that has been used conventionally and delineates a time for monitoring pBtO(2) that is predictive of outcome. LEVEL OF EVIDENCE: III, prognostic study.

Cerebral perfusion pressure and intracranial pressure are not surrogates for brain tissue oxygenation in traumatic brain injury.

OBJECTIVE: Utilization of brain tissue oxygenation (pBtO(2)) is an important but controversial variable in the treatment of traumatic brain injury (TBI). We evaluated the correlation between pBtO(2)/CPP and pBtO(2)/ICP and determined the parameter most closely related to survival. METHODS: Consecutive, adult patients with severe TBI and pBtO(2) monitors were retrospectively identified. Time-indexed measurements of pBtO(2), CPP and ICP were collected and correlation coefficients were determined. Patients were then stratified according to survival and pBtO(2), CPP and ICP values were compared between groups. RESULTS: There were 4169 time-indexed data points (i.e., pBtO(2) with respective CPP and ICP values) in 15 patients. The cohort consisted of a mean age of 37±17 years, ISS of 27±7 and GCS of 4.5±1.5. Survival was 53% (8/15). In a normal regression models, neither the ICP (p=0.58) nor the CPP (p=0.71) predict pBtO(2) significantly. There was a significant difference in pBtO(2) in survivors (31.5±3.1 vs. 25.2±4.8, p=0.010) but not in CPP or ICP. Survivors had a lower proportion of time with pBtO(2)<25 mmHg [20% (3.4-44.6) vs. 40% (16.2-89), p=0.049]. In contrast, survivors had a greater proportion of time with CPP<70 and no difference in the proportion of time with and ICP>20. CONCLUSIONS: CPP and ICP should not be used as surrogates for pBtO(2) since cerebral oxygenation varies independently of cerebral hemodynamics and pressures. Brain tissue oxygen monitoring in patients with TBI provides unique information regarding cerebral oxygenation the utility of which remains to be fully described. SIGNIFICANCE: CPP and ICP are not surrogates for pBtO(2). Brain tissue oxygenation monitoring provides unique information for the treatment of traumatically injured patients.

Tight blood glucose control in trauma patients: Who really benefits?

BACKGROUND: This study was designed to evaluate the effect of intensive insulin control (IIT) on outcomes for traumatically injured patients as a function of injury severity score (ISS) and age. PATIENTS AND METHODS: A retrospective review of 2028 adult trauma patients admitted to the surgical intensive care unit (SICU) in a Level I trauma center was performed. Data were collected from a 48-month period before (Pre-IIT) (goal blood glucose 80-200 mg/dL) and after (Post-IIT) (goal blood glucose level 80-110 mg/dL), an IIT protocol was initiated. Patients were stratified by age and ISS. The primary endpoint was mortality. RESULTS: There were 784 Pre-IIT and 1244 Post-IIT patients admitted. There was no significant difference between Pre-IIT vs. Post-IIT for the mechanism of injury or ISS. Values for the Pre-IIT group were significantly higher for mortality (21.5% vs. 14.7%, P<0.001) and hospital, but not ICU length of stay were decreased. A significant improvement in mortality was demonstrated between Pre-IIT vs. Post-IIT stratified within the age groups of 41-50, 51-60, and 61 but not the groups 18-30 and 31-40. Mean glucose levels (mg/dL) decreased significantly after the institution of IIT (144.7±1.4 vs. 130.9±0.9; P<0.001). In addition, the occurrence per patient of blood glucose levels <40 mg/dL increased (0.77% vs. 2.86%; P=0.001) and blood glucose levels greater than 200 mg/dL was similar (39.1% vs. 38.8%; P=0.892) in the Pre-IIT and Post-IIT groups, respectively. Glycemic variability, reflected by the standard deviation of each patient's mean glucose level during ICU stay, as well as mean glucose level were lower in survivors than in nonsurvivors. Finally, multivariable logistic regression analysis identified both mean glucose level and glycemic variability as independent contributors to the risk of mortality. CONCLUSIONS: The implementation of IIT has been associated with a decrease in both hospital length of stay as well as mortality. Average glucose value and glucose variability are independent predictors of survival. Trauma patients with moderate, severe, and very severe injuries benefit most from IIT. These observational data suggest that patients over 40 years of age benefited a great deal more than their younger counterparts from IIT. This study supports the need for a randomized controlled trial to investigate the role of IIT in traumatically injured patients.

How surgical faculty and residents assess the first year of the Accreditation Council for Graduate Medical Education duty-hour restrictions: results of a multi-institutional study.

BACKGROUND: This study examined how surgical residents and faculty assessed the first year of the Accreditation Council for Graduate Medical Education duty-hour restrictions. METHODS: Questionnaires were administered in 9 general-surgery programs during the summer of 2004; response rates were 63% for faculty and 58% for residents (N = 259). Questions probed patient care, the residency program, quality of life, and overall assessments of the duty-hour restrictions. Results include the means, mean deviations, percentage who agree or strongly agree with the hour restrictions, and significance tests. RESULTS: Although most support the restrictions, few maintain that they improved surgical training or patient care. Faculty and residents differed (P < or = .05) on 16 of 21 items. Every difference shows that residents view the restrictions more favorably than faculty. The sex of the resident shaped the magnitude of the gap for 11 of 21 items. CONCLUSIONS: Few believe that duty-hour restrictions improve patient care or resident training. Residents, especially female residents, view the restrictions more favorably than faculty.

Duty-hour restrictions and the work of surgical faculty: results of a multi-institutional study.

PURPOSE: To examine whether duty-hour restrictions have been consequential for various aspects of the work of surgical faculty and if those consequences differ for faculty in academic and nonacademic general surgery residency programs. METHOD: Questionnaires were distributed in 2004 to 233 faculty members in five academic and four nonacademic U.S. residency programs in general surgery. Participation was restricted to those who had been faculty for at least one year. Ten items on the questionnaire probed faculty work experiences. Results include means, percentages, and t-tests on mean differences. Of the 146 faculty members (63%) who completed the questionnaire, 101 volunteered to be interviewed. Of these, 28 were randomly chosen for follow-up interviews that probed experiences and rationales underlying items on the questionnaire. Interview transcripts (187 single-spaced pages) were analyzed for main themes. RESULTS: Questionnaire respondents and interviewees associated duty-hour restrictions with lowered faculty expectations and standards for residents, little change in the supervision of residents, a loss of time for teaching, increased work and stress, and less satisfaction. No significant differences in these perceptions (p < or = .05) were found for faculty in academic and nonacademic programs. Main themes from the interviews included a shift of routine work from residents to faculty, a transfer of responsibility to faculty, more frequent skill gaps at night, a loss of time for research, and the challenges of controlling residents' hours. CONCLUSIONS: Duty-hour restrictions have been consequential for the work of surgical faculty. Faculty should not be overlooked in future studies of duty-hour restrictions.

Early tracheostomy versus late tracheostomy in the surgical intensive care unit.

BACKGROUND: This study's purpose was to determine if early tracheostomy (ET) of severely injured patients reduces days of ventilatory support, the frequency of ventilator-associated pneumonia (VAP), and surgical intensive care unit (SICU) length of stay (LOS). METHODS: This 2-year retrospective review included 185 SICU patients with acute injuries requiring mechanical ventilation and tracheostomy. ET was defined as 7 days or less, and late tracheostomy (LT) as more than 7 days. RESULTS: The incidence of VAP was significantly higher in the LT group, relative to the ET group (42.3% vs. 27.2%, respectively; P <.05). Acute Physiology and Chronic Health Evaluation II scores, hospital and SICU LOS, and the number of ventilator days were significantly higher in the LT group. CONCLUSIONS: In patients who required prolonged mechanical ventilation, there was significant decreased incidence of VAP, less ventilator time, and lower ICU LOS when tracheostomy was performed within 7 days after admission to the SICU.

Recombinant factor VIIa for the treatment of severe postoperative and traumatic hemorrhage.

BACKGROUND: The aim of this study was to determine the dose of recombinant factor VIIa (rFVIIa) that has been used in our institution to successfully control hemorrhage in trauma and postoperative patients. METHODS: This was an 8-month retrospective cohort study of 13 patients with acute hemorrhage and no known history of coagulopathic disorders. RESULTS: Administration of factor VIIa resulted in the cessation of life-threatening hemorrhage at dosages approximately one half those recommended for the management of hemophilia. After administration, there was a significant decrease in the total blood-product transfusion requirement (P <0.05). CONCLUSIONS: The use of factor VIIa in patients with life-threatening hemorrhage is a safe and effective therapeutic modality when used as an adjunct to standard interventions for control of severe hemorrhage. Lower-dose regimens were as successful as higher-dose regimens previously reported. The results of this respective study of 13 patients suggests that recombinant factor VIIa therapy for control of life-threatening hemorrhage as an adjunct to standard interventions can be successful at doses <90 mg/kg.