Stephen M. Cohn

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%.

Pulmonary contusion: review of the clinical entity.

Pulmonary contusion is a common lesion occurring in patients sustaining severe blunt chest trauma. Alveolar hemorrhage and parenchymal destruction are maximal during the first 24 hours after injury and then usually resolve within 7 days. The diagnosis of traumatic lung injury is usually made clinically with confirmation by chest x-ray films. The chest computed tomography scan is highly sensitive in identifying pulmonary contusion and may help predict the need for mechanical ventilation. Respiratory distress is common after lung trauma, with hypoxemia and hypercarbia greatest at about 72 hours. Although management of patients with pulmonary contusion is supportive, pneumonia and adult respiratory distress syndrome with long-term disability occur frequently.

Can near-infrared spectroscopy identify the severity of shock in trauma patients?

BACKGROUND Our recent experimental study showed that peripheral muscle tissue oxygen saturation (StO2), determined noninvasively by near-infrared spectroscopy (NIRS), was more reliable than systemic hemodynamics or invasive oxygenation variables as an index of traumatic shock. The purpose of this study was to establish the normal range of thenar muscle StO2 in humans and the relationship between shock state and StO2 in trauma patients. METHODS This was a prospective, nonrandomized, observational, descriptive study in normal human volunteers (n = 707) and patients admitted to the resuscitation area of our Level I trauma center (n = 150). To establish a normal StO2 range, an NIRS probe was applied to the thenar eminence of volunteers (normals). Subsequently, in a group of trauma patients, an NIRS probe was applied to the thenar eminence and data were collected and stored for offline analysis. StO2 monitoring was performed continuously and noninvasively, and values were recorded at 2-minute intervals. Five moribund trauma patients were excluded. Members of our trauma faculty, blinded to StO2 values, classified each patient into one of four groups (no shock, mild shock, moderate shock, and severe shock) using conventional physiologic parameters. RESULTS Mean +/- SD thenar StO2 values for each group were as follows: normals, 87 +/- 6% (n = 707); no shock, 83 +/- 10% (n = 85); mild shock, 83 +/- 10% (n = 19); moderate shock, 80 +/- 12% (n = 14); and severe shock, 45 +/- 26% (n = 14). The thenar StO2 values clearly discriminated the normals or no shock patients and the patients with severe shock (p < 0.05). CONCLUSION Decreased thenar muscle tissue oxygen saturation reflects the presence of severe hypoperfusion and near-infrared spectroscopy may be a novel method for rapidly and noninvasively assessing changes in tissue dysoxia.

Early fracture fixation may be deleterious after head injury

OBJECTIVE To determine the neurologic risks associated with early fracture fixation (FF) in multitrauma patients with head injuries. METHODS We reviewed 33 blunt trauma patients with significant closed head injuries (Abbreviated Injury Scale (AIS) score > or = 2) requiring operative FF. Nineteen patients underwent early FF defined as < or = 24 hours after injury, and 14 patients underwent late FF defined as > 24 hours after injury. The two groups were well matched in regards to age, 40.3 years (range, 8-88 years) versus 36.4 years (range, 8-75 years), admission Glasgow Coma Scale score (12 +/- 4 vs. 11 +/- 5), and Injury Severity Score (25 +/- 10 vs. 27 +/- 12). Additionally, the groups had similar neurologic and orthopedic injury scores (AIS-CNS score = 3.3 +/- 0.9 vs. 3.1 +/- 0.9, AIS-Ortho score = 3.0 +/- 0.9 vs. 2.9 +/- 0.7). Data were collected concerning the volume of fluid resuscitation, neurologic complications, and clinical outcomes. RESULTS The early FF group received significantly more fluids in the first 48 hours (14.0 +/- 10.2 vs. 8.7 +/- 3.5 liters, p < 0.05). The early group trended towards a higher rate of intraoperative hypotension (systolic blood pressure < 90 mm Hg, 16% vs. 7%) and intraoperative hypoxia (O2-Saturation < or = 90, 11% vs. 7%). The neurologic complication rate was similar in the two groups (early FF = 16% vs. late FF = 21%), but the average discharge Glasgow Coma Scale score was lower in the early group (13.5 +/- 3.7) when compared with the late FF patient group (15.0 +/- 0.0). CONCLUSIONS Early FF leads to greater fluid administration in patients with head injuries. Hypoxemia and hypotension, risk factors for secondary brain injury, may contribute to a poor neurologic outcome after early fixation. Prospective studies evaluating the impact of the timing of FF on head injury are indicated.

2,576 Ultrasounds for blunt abdominal trauma

BACKGROUND Determination of intra-abdominal injury following blunt abdominal trauma (BAT) continues to be a diagnostic challenge. Ultrasound (US) has been described as a potentially useful diagnostic tool in this setting and is being used with increasing frequency in trauma centers. We determined the diagnostic capability of US in the evaluation of BAT. METHODS A retrospective analysis of our trauma US database was performed over a 30-month period. Computed tomographic scan, diagnostic peritoneal lavage, or exploratory laparotomy confirmed the presence of intra-abdominal injury. RESULTS During the study period, 8,197 patients were evaluated at the Ryder Trauma Center. Of this group, 2,576 (31%) had US in the evaluation of BAT. Three hundred eleven (12%) US exams were considered positive. Forty-three patients (1.7%) had a false-negative US; of this group, 10 (33%) required exploratory laparotomy. US had a sensitivity of 86%, a specificity of 98%, and an accuracy of 97% for detection of intra-abdominal injuries. Positive predictive value was 87% and negative predictive value was 98%. CONCLUSION Emergency US is highly reliable and may replace computed tomographic scan and diagnostic peritoneal lavage as the initial diagnostic modality in the evaluation of most patients with BAT.

Fiberoptic endoscopic documentation of the high incidence of aspiration following extubation in critically ill trauma patients.

Abstract. The purpose of this study was to investigate the incidence of aspiration following extubation in critically ill trauma patients. This prospective pilot study included 20 consecutive trauma patients who required orotracheal intubation for at least 48 hours. All subjects underwent a bedside transnasal fiberoptic endoscopic evaluation of swallowing at 24 ± 2 hr after extubation to determine objectively aspiration status. Aspiration was defined as the entry of a blue dyed material into the airway below the level of the true vocal folds, with silent aspiration occurring in the absence of any external behavioral signs such as coughing or choking. Aspiration was identified in 9 of 20 (45%) subjects and 4 of these 9 (44%) were silent aspirators. Therefore, silent aspiration occurred in 20% of the study population. Eight of the 9 (89%) aspirating subjects resumed an oral diet from 2–10 days (mean, 5 days) following extubation. All subjects had no evidence of pulmonary complications. It was concluded that trauma patients after orotracheal intubation and prolonged mechanical ventilation have an increased risk of aspiration. An objective assessment of dysphagia to identify aspiration may reduce the likelihood of pulmonary complications after extubation.

Postextubation fiberoptic endoscopic evaluation of swallowing after prolonged endotracheal intubation: a randomized, prospective trial.

BackgroundCritically ill trauma patients frequently require prolonged endotracheal intubation and ventilator support. After extubation, swallowing difficulties may exist in ≤50% of patients. We sought to determine whether performing a swallowing evaluation would reduce the incidence of postextubation aspiration and subsequent pneumonia. DesignRandomized, prospective clinical trial of fiberoptic endoscopic evaluation of swallowing (FEES) vs. routine clinical management in patients after prolonged intubation. MethodsSeventy patients who were intubated for >48 hrs were randomized. FEES examinations were performed within 24 ± 2 hrs after extubation. Silent aspiration was defined as the appearance of liquid or puree bolus below the true vocal cords without coughing during a FEES examination. Clinical aspiration was defined as the removal of enteral content from below the vocal cords, usually during endotracheal tube placement. ResultsThere were five episodes of aspiration and pneumonia in the FEES group (14%, two silent) and two in the clinical group (6%, not significant, Fisher exact test). Patients aged >55 yrs and those with vallecular stasis on FEES examination were at significantly higher risk of postextubation aspiration. All patients with pneumonia had an associated aspiration episode. ConclusionsPatients with prolonged orotracheal intubation are at risk of aspiration after extubation. The addition of a FEES examination did not change the incidence of aspiration or postextubation pneumonia.

Incidence and Susceptibility of Pathogenic Bacteria Vary between Intensive Care Units within a Single Hospital: Implications for Empiric Antibiotic Strategies

BACKGROUND The purpose of this study was to determine whether the incidence of recovery and patterns of antibiotic susceptibility of pathogenic bacteria vary between intensive care units (ICUs) in a single teaching hospital. METHODS Culture and susceptibility results were collected prospectively for a 3-month period (April through June 1999) in each of the surgical, trauma, and medical ICUs. The number of unique isolates and susceptibility patterns were determined. Susceptibility of isolates among ICUs was compared with chi2. RESULTS Statistically significant differences between ICUs in susceptibility to various antibiotics were found for Staphylococcus aureus, Enterococcus sp, Acinetobacter sp, Enterobacter sp, Klebsiella sp, and Pseudomonas sp. Notably, vancomycin-resistant Enterococcus was not seen in the medical ICU, whereas it was seen in both the surgical and trauma ICUs. Klebsiella spp resistant to ceftazidime were seen only in the trauma ICU. The aminoglycosides and quinolones had attenuated activity against Pseudomonas sp in the surgical ICU, whereas they remained highly effective in the trauma ICU. Cefazolin had no activity against the Enterobacter sp in either of the surgical ICUs, but was highly effective in the medical ICU. CONCLUSION Although the microbiologic results of this study should not be extrapolated to other institutions, the principle is of value. There is variability between ICUs in a single large teaching hospital in susceptibility of bacterial pathogens to various antibiotics. This may have implications in the design of empiric antibiotic strategies and the planning of the hospital formulary. Hospital wide or composite ICU antibiograms are inadequate for planning empiric therapy in the ICU.

Utility of near-infrared spectroscopy in the diagnosis of lower extremity compartment syndrome.

OBJECTIVE To determine the utility of near-infrared spectroscopy in the diagnosis of lower extremity compartment syndrome (CS). METHODS Nine patients with CS confirmed by physical examination and elevated compartment pressures (64 +/- 17 mm Hg) were evaluated before and after fasciotomy. Control readings were also performed on 33 surgical patients who had no evidence of CS. The deltoid muscle was used as a reference value. RESULTS The deltoid muscle oxygen saturation (StO2) readings revealed a mean = 84 +/- 17% prefasciotomy and mean = 83 +/- 12% postfasciotomy in the CS group. The control group had a mean StO2 of 83 +/- 11%. In the CS group, the leg compartment with the highest pressure had a StO2 mean = 56 +/- 27% before fasciotomy. This value was statistically significantly lower (p < 0.05) than either the postfasciotomy mean StO2 in that compartment (82 +/- 16%) or the values found in matched control patients with no evidence of CS (87 +/- 7%). CONCLUSION Near-infrared spectroscopy-derived StO2 values in the lower extremities of trauma patients with CS were diminished relative to the control patients and usually normalized after fasciotomy. Near-infrared spectroscopy evaluation may offer a rapid, noninvasive method of assessing extremities at risk for CS.

Massive transfusion in trauma patients: tissue hemoglobin oxygen saturation predicts poor outcome.

BACKGROUND Severely bleeding trauma patients requiring massive transfusion (MT) often experience poor outcomes. Our purpose was to determine the potential role of near infrared spectrometry derived tissue hemoglobin oxygen saturation (StO2) monitoring in early prediction of MT, and in the identification of those MT patients who will have poor outcomes. METHODS Data from a prospective multi-institution StO2 monitoring study were analyzed to determine the current epidemiology of MT (defined as transfusion volume >/=10 units packed red blood cells in 24 hours of hospitalization). Multivariate logistic regression was used to develop prediction models. RESULTS Seven US level I trauma centers (TC) enrolled 383 patients. 114 (30%) required MT. MT progressed rapidly (40% exceeded MT threshold 2 hours after TC arrival, 80% after 6 hours). One third of MT patients died. Two thirds of deaths were due to early exsanguination and two thirds of early exsanguination patients died within 6 hours. One third of the early MT survivors developed multiple organ dysfunction syndrome. MT could be predicted with standard, readily available clinical data within 30 minutes and 60 minutes of TC arrival (area under the receiver operating characteristic curve = 0.78 and 0.80). In patients who required MT, StO2 was the only consistent predictor of poor outcome (multiple organ dysfunction syndrome or death). CONCLUSION MT progresses rapidly to significant morbidity and mortality despite level I TC care. Patients who require MT can be predicted early, and persistent low StO2 identifies those MT patients destined to have poor outcome. The ultimate goal is to identify these high risk patients as early as possible to test new strategies to improve outcome. Further validation studies are needed to analyze appropriate allocation and study appropriate use of damage control interventions.