Observation unit admission as an alternative to inpatient admission for trauma activation patients.

BACKGROUND: At this 35 000 visits/year emergency department (ED) at a level one trauma centre, a trauma protocol was implemented for the ED observation unit. Data on all trauma observation unit admissions were then collected to evaluate for safety, efficiency and admission rates. METHODS: A retrospective chart review was performed of all trauma patients in the observation unit during a 14-month period. Exclusion criteria for observation unit admission included: abnormal vital signs, positive focussed abdominal sonography for trauma examination, abnormal ECG, abnormal chest radiograph, abnormal head computed tomography, Glasgow coma score less than 14, or multisystem trauma. RESULTS: 364 trauma patients were admitted to the observation unit. 84.6% were trauma II activations and 3.8% were trauma I activations. There were no deaths, intubations, loss of vital signs or other adverse events. The average length of stay was 12 h 46 minutes and 11.5% of patients were admitted to an inpatient unit. At 30-day follow-up, there were no significant missed injuries. CONCLUSION: The observation unit is a safe alternative to inpatient admission for the evaluation of the minimally injured trauma activation patient.

Visual acuity after topical application of proparacaine.

STUDY OBJECTIVE: To determine the effect of topical anesthetics on visual acuity (VA). METHODS: We studied 66 consecutive patients (73 afflicted eyes) who presented to a university hospital emergency department with the complaint of eye pain. VA was measured before and after patients were treated with proparacaine, a topical ocular anesthetic. RESULTS: After proparacaine instillation, VA was improved in 33 patients (45%), unchanged in 34 (47%), and worse in 6 (8%). CONCLUSION: Patients with eye pain often demonstrate improved VA after the instillation of a topical anesthetic.

Cardiovascular effects of carbamazepine toxicity.

STUDY OBJECTIVE: To evaluate the cardiovascular effects of carbamazepine in patients presenting to the emergency department. DESIGN: A retrospective case series from February 1, 1985, to July 30, 1993. SETTING: Six urban EDs. PARTICIPANTS: Seventy-two adult and pediatric patients with serum carbamazepine concentrations greater than 12 micrograms/mL and concurrent 12-lead ECGs. RESULTS: The mean carbamazepine level was 24 micrograms/mL (range, 12.6 to 55 micrograms/mL). Minor ECG abnormalities were noted but no clinically significant arrhythmias were found. No correlation was found between carbamazepine concentration and heart rate or PR, QRS, or corrected QT intervals. Four adult patients had transient hypotension. CONCLUSION: Clinically significant cardiovascular toxicity occurs rarely in patients with toxic carbamazepine concentrations. ECG findings do not correlate with serum carbamazepine concentration.

Demographic and electrocardiographic factors associated with severe tricyclic antidepressant toxicity.

This study was designed to evaluate a historic cohort of pure tricyclic antidepressant overdose patients for factors associated with severe toxicity. Hospitalized tricyclic antidepressant overdose patients were identified by computerized discharge diagnosis (ICD-9 codes). Patients with a serum drug screen positive for tricyclic antidepressants and an emergency department 12-lead electrocardiogram were included in the study. Multiple drug overdoses were excluded. Patients were divided into two groups: minor toxicity (n = 41 and major toxicity (n = 65). Criteria for inclusion in the major toxicity group were the occurrence of seizures, endotracheal intubation, coma, arrhythmias requiring treatment, hypotension, or death. The following were found to be associated with increased likelihood of major toxicity (p less than 0.05): ingestion of amitriptyline (odds ratio (OR) 2.57), age greater than or equal to 30 years (OR 2.56), heart rate greater than or equal to 120 bpm (OR 2.86), serum tricyclic antidepressant level greater than or equal to 800 ng/mL (OR 5.20), terminal 40 ms QRS axis (T40-ms axis) greater than or equal to 135 degrees (OR 2.73), QRS interval greater than or equal to 100 ms (OR 2.74), QRS axis greater than 90 degrees (OR 3.68), and QTc interval greater than 480 ms (OR 3.89). The mean T40-ms axis on the initial ECG was more rightward in the major toxicity group (174 +/- 84 vs 125 +/- 91 degrees, p = 0.006). We conclude that patients with severe tricyclic antidepressant toxicity tended to have a more rightward T40-ms axis than those with minor toxicity and that the presence of the above parameters was associated with an increased likelihood of severe toxicity.

Intravenous catheter aspiration for obtaining basic analytes during intravenous infusion.

The aspiration of blood through a functioning IV line to obtain samples for laboratory analysis was evaluated. Thirty-eight emergency department patients were studied. Each had an 18-gauge IV catheter placed and then received a 100-mL bolus of either normal saline, lactated Ringer's, or 5% dextrose in water. Two samples of blood ("first aspirate" and "second aspirate") were then aspirated from the IV catheter while one sample was obtained by venipuncture from the opposite arm (control). All three samples were then analyzed for CBC, electrolytes, BUN, creatinine, and glucose. Catheter aspiration succeeded in 30 of 38 attempts (79%). Three samples were hemolyzed, and five samples were unable to be fully aspirated. Results of paired t testing showed only occasional statistical significance and except for bicarbonate were not of clinical significance. This study suggests that catheter aspiration is a useful method of obtaining blood for certain laboratory tests in patients receiving IV infusions.

Nifedipine for the relief of renal colic: a double-blind, placebo-controlled clinical trial.

Pain from ureteral stones is believed to be due to spasm and hyper-peristalsis of the involved ureter. Nifedipine has been shown to decrease human ureteral spasm in vitro. Conflicting results have been reported concerning the clinical efficacy of nifedipine in relieving acute renal colic. This prospective, double-blind, crossover clinical trial evaluated the acute pain relief obtained in 30 patients who had ureteral stones. All patients had ureteral stones documented either by plain abdominal radiograph (six), intravenous pyelogram (16), or passage of the stone(s) in the urine (eight). Each patient served as his own control. The mean pain relief scores for placebo versus 10 to 20 mg oral nifedipine were 0.7 +/- 1.8 and 1.2 +/- 2.5, respectively, as measured on a visual analogue scale (P = .404). Seven patients received clinically significant relief associated with nifedipine, and three patients received relief from placebo (P = .300). Twenty patients (66%) did not experience clinically significant relief from either treatment. We conclude that nifedipine does not differ significantly from placebo in providing relief from acute renal colic.

Crystallization and preliminary X-ray analysis of type B influenza virus neuraminidase complexed with antibody Fab fragments.

Fab fragments from four different monoclonal antibodies have been complexed with influenza B virus neuraminidase (B/Lee/40) and the complexes have been crystallized. Three of the complex crystals are, so far, not suitable for X-ray diffraction studies, but the fourth (B/Lee/40 NA-B1Fab) forms large crystals which diffract X-rays to 3.0 A resolution. The crystals have a space group of F432, a = 441.21 A. Vm calculations show that the asymmetric unit contains two monomeric complexes.

Crystallization and preliminary X-ray analyses of two neuraminidases from influenza B virus strains B/Hong Kong/8/73 and B/Lee/40.

Crystals of neuraminidase heads from two different influenza B virus strains have been grown. Neuraminidase crystals of influenza B/Hong Kong/8/73 were grown from solutions of potassium phosphate. The crystals are tetragonal prisms, space group I422; the axes are a = 123 A and c = 165 A. Influenza B/Lee/40 neuraminidase crystals were grown from solutions of polyethylene glycol 4000. The crystals are tetragonal pyramids, space group P4(1)2(1)2 or its enantiomorph P4(3)2(1)2; the axes are a = 125 A and c = 282 A.

Lack of efficacy of 'weighted' radiographs in diagnosing acute acromioclavicular separation.

The efficacy of "weighted" films in diagnosing grade 3 acromioclavicular (AC) sprains not evident on plain (unweighted) films was evaluated. Eighty-three pairs of radiographs, taken with and without weights, of patients with suspected AC injury were studied. The films were read in a randomized and blinded manner by a staff radiologist. Criteria for classifying AC injuries were: grade 1, less than 3 mm (or less than 50%) difference between the AC widths with a normal coracoclavicular (CC) distance; grade 2, greater than or equal to 3 mm (or greater than or equal to 50%) difference between the AC widths with a normal CC distance; and grade 3, greater than or equal to 5 mm (or greater than or equal to 50%) difference in CC distance. In only three cases (4%) did weights cause the injured CC distance to increase and thereby unmask a grade 3 injury not evident on plain films. Further evidence that weights may not reliably elucidate the degree of AC joint injury is suggested by the fact that in several cases the weights actually caused the injured and uninjured CC distance to decrease. We conclude that the use of weighted radiographs lacks efficacy in unmasking grade 3 AC sprains on radiograph and we recommend that routine use of this technique be abandoned.