Scott B. Frame

Prospective, Randomized Comparison of Epidural Versus Parenteral Opioid Analgesia in Thoracic Trauma

OBJECTIVE To evaluate systemic versus epidural opioid administration for analgesia in patients sustaining thoracic trauma. SUMMARY BACKGROUND DATA The authors have previously shown that epidural analgesia significantly reduces the pain associated with significant chest wall injury. Recent studies report that epidural analgesia is associated with a lower catecholamine and cytokine response in patients undergoing elective thoracotomy compared with patient-controlled analgesia (PCA). This study compares the effect of epidural analgesia and PCA on pain relief, pulmonary function, cathechol release, and immune response in patients sustaining significant thoracic trauma. METHODS Patients (ages 18 to 60 years) sustaining thoracic injury were prospectively randomized to receive epidural analgesia or PCA during an 18-month period. Levels of serum interleukin (IL)-1beta, IL-2, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured every 12 hours for 3 days by enzyme-linked immunosorbent assay. Urinary catecholamine levels were measured every 24 hours. Independent observers assessed pulmonary function using standard techniques and analgesia using a verbal rating score. RESULTS Twenty-four patients of the 34 enrolled completed the study. Age, injury severity score, thoracic abbreviated injury score, and length of hospital stay did not differ between the two groups. There was no significant difference in plasma levels of IL-1beta, IL-2, IL-6, or TNF-alpha or urinary catecholamines between the two groups at any time point. Epidural analgesia was associated with significantly reduced plasma levels of IL-8 at days 2 and 3, verbal rating score of pain on days 1 and 3, and maximal inspiratory force and tidal volume on day 3 versus PCA. CONCLUSIONS Epidural analgesia significantly reduced pain with chest wall excursion compared with PCA. The route of analgesia did not affect the catecholamine response. However, serum levels of IL-8, a proinflammatory chemoattractant that has been implicated in acute lung injury, were significantly reduced in patients receiving epidural analgesia on days 2 and 3. This may have important clinical implications because lower levels of IL-8 may reduce infectious or inflammatory complications in the trauma patient. Also, tidal volume and maximal inspiratory force were improved with epidural analgesia by day 3. These results demonstrate that epidural analgesia is superior to PCA in providing analgesia, improving pulmonary function, and modifying the immune response in patients with severe chest injury.

Institutional and Individual Learning Curves for Focused Abdominal Ultrasound for Trauma: Cumulative Sum Analysis

OBJECTIVE To evaluate both institutional and individual learning curves with focused abdominal ultrasound for trauma (FAST) by analyzing the incidence of diagnostic inaccuracies as a function of examiner experience for a group of trauma surgeons performing the study in the setting of an urban level I trauma center. SUMMARY BACKGROUND DATA Trauma surgeons are routinely using FAST to evaluate patients with blunt trauma for hemoperitoneum. The volume of experience required for practicing trauma surgeons to be able to perform this examination with a reproducible level of accuracy has not been fully defined. METHODS The authors reviewed prospectively gathered data for all patients undergoing FAST for blunt trauma during a 30-month period. All FAST interpretations were validated by at least one of four methods: computed tomography, diagnostic peritoneal lavage, celiotomy, or serial clinical evaluations. Cumulative sum (CUSUM) analysis was used to describe the learning curves for each individual surgeon at target accuracy rates of 85%, 90%, and 95% and for the institution as a whole at target examination accuracy rates of 85%, 90%, 95%, and 98%. RESULTS Five trauma surgeons performed 546 FAST examinations during the study period. CUSUM analysis of the aggregate experience revealed that the examiners as a group exceeded 90% accuracy at the outset of clinical examination. The level of accuracy did not improve with either increased frequency of performance or total examination experience. The accuracy rates observed for each trauma surgeon ranged from 87% to 98%. The surgeon with the highest accuracy rate performed the fewest examinations. No practitioner demonstrated improved accuracy with increased experience. CONCLUSIONS Trauma surgeons who are newly trained in the use of FAST can achieve an overall accuracy rate of at least 90% from the outset of clinical experience with this modality. Interexaminer variations in accuracy rates, which are observed above this level of performance, are probably related more to issues surrounding patient selection and inherent limitations of the examination in certain populations than to practitioner errors in the performance or interpretation of the study.

Adrenergic Antagonists Reduce Lactic Acidosis in Response to Hemorrhagic Shock

BACKGROUND Hemorrhagic shock is associated with lactic acidosis and increased plasma catecholamines. Skeletal muscle increases lactate production under aerobic conditions in response to epinephrine, and this effect is blocked by ouabain, a specific inhibitor of the cell membrane Na+/K+ pump. In this study, we tested whether adrenergic antagonists can block lactate production during shock. METHODS Male Sprague-Dawley rats (250-300 g) were pretreated with phenoxybenzamine (2 mg/kg, i.v.) and/or propranolol (0.5 mg/kg, i.p.) before hemorrhaging to a mean arterial pressure of 40 mm Hg for 1 hour. Skeletal muscle perfusion, plasma lactate, and catecholamines were measured at baseline, 55 minutes after shock, and 1 hour after resuscitation. In a separate study, extensor digitorum longus and soleus muscles were incubated in Krebs buffer (95:5, O2:CO2) with 10 mmol/L glucose. One of each muscle pair was incubated in the absence or presence of epinephrine and of one or both adrenergic blockers. Medium lactate concentration was then measured. RESULTS The combination of alpha- and beta-blockers significantly reduced plasma lactate levels during hemorrhage. In contrast, beta-blockade alone was associated with a significant increase in plasma lactate and epinephrine. None of the blockers altered tissue perfusion. Epinephrine stimulation of muscle lactate production in vitro was completely blocked by propranolol. CONCLUSION Epinephrine release in response to hypotension is a primary stimulus for muscle lactate production in this model of hemorrhagic shock. Hypoxia alone does not explain the increased lactate levels because tissue perfusion was not altered by the adrenergic antagonists. These observations challenge the rationale behind lactate clearance as an end point for resuscitation after hemorrhagic shock.

Prone positioning and inhaled nitric oxide: synergistic therapies for acute respiratory distress syndrome.

BACKGROUND Inhaled nitric oxide (INO) and prone positioning have both been advocated as methods to improve oxygenation in patients with acute respiratory distress syndrome (ARDS). This study was designed to evaluate the relative contributions of INO and prone positioning alone and in combination on gas exchange in trauma patients with ARDS. METHODS Sixteen patients meeting the consensus definition of ARDS were studied. Patients received mechanical ventilation in the supine position, mechanical ventilation plus INO at 1 part per million in the supine position, mechanical ventilation in the PP, and mechanical ventilation in the prone positioning plus INO at 1 part per million. A stabilization period of 1 hour was allowed at each condition. After stabilization,hemodynamic and gas exchange variables were measured. RESULTS INO and prone positioning both increased PaO2/FIO2 compared with ventilation in the supine position. PaO2/FIO2 increased by 14% during use of INO, and 10 of 16 patients (62%) responded to INO in the supine position. PaO2/FIO2 increased by 33%, and 14 of 16 patients (87.5%) responded to the prone position. The combination of INO and prone positioning resulted in an improvement in PaO2/FIO2 in 15 of 16 patients(94%), with a mean increase in PaO2/FIO2 of 59%. Pulmonary vascular resistance was reduced during use of INO, with a greater reduction in pulmonary vascular resistance seen with INO plus prone positioning (175 +/- 36 dynes x s/cm5 vs. 134 +/- 28 dynes x s/cm5) compared with INO in the supine position (164 +/- 48 dynes x s/cm5 vs.138 +/- 44 dynes x s/cm5). There were no significant hemodynamic effects of INO or prone positioning and no complications were seen during this relative short duration of study. CONCLUSIONS INO and prone positioning can contribute to improved oxygenation in patients with ARDS. The two therapies in combination are synergistic and may be important adjuncts to mechanical ventilation in the ARDS patient with refractory hypoxemia.

Zone I retroperitoneal hematoma identified by computed tomography scan as an indicator of significant abdominal injury

OBJECTIVE All zone I retroperitoneal hematomas (Z1RPHs) identified at laparotomy for blunt trauma traditionally require exploration. The purpose of this study was to correlate patient outcome after blunt abdominal trauma with the presence of Z1RPH diagnosed on admission computed tomography (CT) scan. METHODS This is a retrospective review of patients with blunt trauma who were admitted to a Level 1 trauma center and who underwent CT scan during a 40-month period. All scans with a traumatic injury were reviewed to identify and grade Z1RPH as mild, moderate, or severe. Patients requiring operative treatment were compared with those who were observed. Statistical analysis was performed with Students t test and chi-square test, with P < .05 considered significant. RESULTS Eighty-five (15.5%) of the CT scans were positive for Z1RPH. None of the 50 patients with a mild Z1RPH had their treatment altered. Of the 29 patients with a moderate or severe Z1RPH, 8 required celiotomy. The patients requiring celiotomy had significant elevations of solid viscus score (SVS) (4.9 +/- 1.6 versus 1.8 +/- 0.3), abdominal Abbreviated Injury Scale (3.8 +/- 0.3 versus 2.6 +/- 0.3), and transfusion requirements (13 +/- 4 versus 2 +/- 1). All patients (N = 4) with an SVS >4 required operative treatment. Seventy-two percent of patients with more than 1 intra-abdominal injury required abdominal exploration. CONCLUSIONS The presence of a moderate or severe Z1RPH and more than 1 intra-abdominal injury or an SVS >4 on admission CT scan is an important radiographic finding. This injury pattern should be considered a contraindication for nonoperative treatment of the associated solid organ injury.

Synchronized Independent Lung Ventilation in the Management of Pediatric Unilateral Pulmonary Contusion: Case Report

Utilizing a double-lumen endobronchial tube, synchronized independent lung ventilation (SILV) was successfully employed to manage severe unilateral pulmonary contusion in a 6-year old trauma patient. This appears to represent the youngest reported patient in whom this technique has been utilized. Early institution of this treatment modality may substantially increase survival.