Prospective multicenter evaluation of the pulmonary embolism rule-out criteria.

BACKGROUND: Over-investigation of low-risk patients with suspected pulmonary embolism (PE) represents a growing problem. The combination of gestalt estimate of low suspicion for PE, together with the PE rule-out criteria [PERC(-): age < 50 years, pulse < 100 beats min(-1), SaO(2) >or= 95%, no hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within 4 weeks, no prior venous thromboembolism (VTE), and no unilateral leg swelling], may reduce speculative testing for PE. We hypothesized that low suspicion and PERC(-) would predict a post-test probability of VTE(+) or death below 2.0%. METHODS: We enrolled outpatients with suspected PE in 13 emergency departments. Clinicians completed a 72-field, web-based data form at the time of test order. Low suspicion required a gestalt pretest probability estimate of <15%. The main outcome was the composite of image-proven VTE(+) or death from any cause within 45 days. RESULTS: We enrolled 8138 patients, 85% of whom had a chief complaint of either dyspnea or chest pain. Clinicians reported a low suspicion for PE, together with PERC(-), in 1666 patients (20%). At initial testing and within 45 days, 561 patients (6.9%, 95% confidence interval 6.5-7.6) were VTE(+), and 56 others died. Among the low suspicion and PERC(-) patients, 15 were VTE(+) and one other patient died, yielding a false-negative rate of 16/1666 (1.0%, 0.6-1.6%). As a diagnostic test, low suspicion and PERC(-) had a sensitivity of 97.4% (95.8-98.5%) and a specificity of 21.9% (21.0-22.9%). CONCLUSIONS: The combination of gestalt estimate of low suspicion for PE and PERC(-) reduces the probability of VTE to below 2% in about 20% of outpatients with suspected PE.

Diagnostic accuracy of a bedside D-dimer assay and alveolar dead-space measurement for rapid exclusion of pulmonary embolism: a multicenter study.

CONTEXT: A previous study suggested that the combination of a normal D-dimer assay and normal alveolar dead-space fraction is a highly sensitive screening test for pulmonary embolism (PE). OBJECTIVE: To determine if the combination of a normal alveolar dead-space fraction (volume of alveolar dead space/tidal volume

Collaboration among emergency medicine physician researchers and statisticians: resources and attitudes.

We examined the statistical resources within emergency medicine residency programs, and the attitudes of emergency medicine physician researchers toward activities wherein collaboration with a statistician is useful. Anonymous surveys were mailed to 104 emergency medicine physician researchers (1/program). Sixty-four (62%) responses were analyzed. Sixty-seven percent of respondents were their program's research director. Their highest level of statistical training was self-taught/nondegree course work for 88% of respondents. Forty-two percent said they were the person used most often by their program for statistical expertise. One-quarter of programs employed a full-time statistician. Collaboration among researchers and statisticians was considered sometimes or always useful for protocol development (aims 84%, design 99%, outcomes 99%, procedures 73%, sampling 97%, inclusion criteria 93%, number of subjects 100%); data entry 73%; statistical analysis 100%; and manuscript preparation 86%. Although most emergency medicine residencies lacked statistical resources within their program, physician researchers expressed positive attitudes toward collaboration with a statistician for all aspects of research.

Serum creatine kinase is an unreliable predictor of ectopic pregnancy.

OBJECTIVE: To compare serum creatine kinase (CK) values in patients with ectopic pregnancy vs patients with threatened miscarriage or normal pregnancy. METHODS: An observational case-control study was performed at an urban teaching hospital. Pregnant women with a quantitative beta-hCG obtained for suspicion of ectopic pregnancy were evaluated. Excluded were cases with recent trauma, i.m. injections, surgery, or history of heart, liver, or muscle disease. The serum beta-hCG and CK values were recorded and compared between groups with 1-way ANOVA and Tukey's multiple comparison procedure at the overall 0.05 level. RESULTS: The 15 ectopic, 28 threatened miscarriage, and 21 normal pregnancy cases were of similar gestational ages (p = 0.2), ranging from 3 to 12 weeks. Although the CK values for ectopic pregnancy (88.8 +/- 33.6 IU/L) exceeded those for threatened miscarriage (65.9 +/- 59.0 IU/L) and normal pregnancy (56.0 +/- 38.1 U/L) (p = 0.02), there was significant overlap between groups. CK values were at or above a cutoff of 74 IU/L in 80% (95% confidence interval: 52-96%) of ectopic pregnancies, 25% (11-45%) of threatened miscarriages, and 14% (3-36%) of normal pregnancies. CONCLUSIONS: Although the ectopic pregnancy population is characterized by a higher mean CK than are patients with threatened miscarriage or a normal pregnancy, a significant overlap in CK values makes use of this serum marker unreliable for detecting ectopic pregnancy.

The false-positive rate of thoracic outlet syndrome shoulder maneuvers in healthy subjects.

OBJECTIVE: To estimate the incidence of false-positive findings of thoracic outlet syndrome (TOS) shoulder maneuvers, Adson's test (AT), costoclavicular maneuver (CCM), elevated arm stress test (EAST), and supraclavicular pressure (SCP) in healthy subjects. METHODS: A cross-sectional, observational study was performed in a medical school and affiliated emergency medicine residency program setting. Participants included healthy adult volunteers without symptoms of TOS. The shoulder maneuvers AT, CCM, EAST, and SCP were performed in randomized order for 30 sec, 30 sec, 3 min, and 30 sec, respectively. Pulse quality and the presence and timing of pain or paresthesias were assessed. RESULTS: 53 subjects were enrolled, including 27 women, aged 29.7 +/- 6.4 years (range 21-58 years). AT, CCM, EAST, and SCP resulted in an altered pulse in 11%, 11%, 62%, and 21%; pain in 0%, 0%, 21%, and 2%; and paresthesias in 11%, 15%, 36%, and 15% of cases, respectively. The following outcomes had reasonable false-positive rates (upper 95% confidence limit): pain with the AT (7%), CCM (7%), SCP (10%), or any 2 TOS shoulder maneuvers (10%); discontinuing the EAST because of symptoms (16%); or any symptom with 3 (13%) or 4 (7%) TOS shoulder maneuvers. CONCLUSIONS: In a study of TOS shoulder maneuvers in healthy subjects, the outcomes of pulse alteration or paresthesias were unreliable in general. However, TOS shoulder maneuvers have reasonably low false-positive rates when a positive outcome is defined as pain after AT, CCM, or SCP; discontinuation of the EAST secondary to pain; pain in the same arm with > or =2 maneuvers; or any symptom in the same arm with > or =3 maneuvers.

Effects of simulated mouth-to-mouth ventilation during external cardiac compression or active compression-decompression in a swine model of witnessed cardiac arrest.

STUDY OBJECTIVE: To assess the effects of simulated mouth-to-mouth (MTM) ventilation on blood gases, gas exchange, and minute ventilation during external cardiac compression (ECC) or active compression-decompression (ACD) in a swine model of witnessed cardiac arrest and bystander CPR. METHODS: Twenty swine were anesthetized, intubated, ventilated with room air, and monitored for aortic and right atrial pressure and blood gas sampling. After 1 minute of ventricular fibrillation cardiac arrest, ECC or ACD was manually performed at a rate of 100 per minute for 12 minutes. Animals in the room air group had their endotracheal tubes open to air, whereas those in the MTM group were mechanically ventilated with a gas mixture of 16% oxygen and 4% carbon dioxide. Arterial and venous PO2, PCO2, and pH values; oxygen consumption (VO2); carbon dioxide production (VCO2); and minute ventilation (VE) were measured at baseline and 1, 5, 9, and 13 minutes after induction of cardiac arrest. RESULTS: MTM ventilation did not alter arterial or venous PO2 values in comparison with room air but did result in higher arterial PCO2 values at 5 and 9 minutes (although the mean PCO2 was 40 mm Hg or less [5.3 kPa] in all groups) and significant central venous hypercarbic acidosis at 9 and 13 minutes. Arterial PO2 values were greater in the ACD than the ECC groups at 5, 9, and 13 minutes, although all groups maintained acceptable PO2 (mean values > or = 60 mm Hg [8.0 kPa]) through 9 minutes of CPR and through 13 minutes in all but the ECC-room air group. PCO2 values were lower in the ACD groups beyond 1 minute, with the ACD-room air group showing extreme hyperventilation (mean PCO2 < or = 20 mm Hg [2.7 kPa]). MTM ventilation resulted in negative VO2 and VCO2 for the first few minutes, reflecting changes in pulmonary gas stores. As equilibrium was approached, VO2 and VCO2 approached zero in all groups, reflecting low cardiac output. MTM ventilation did not improve VE over room air at any time during ACD. It did improve VE during ECC, but only at the 12th interval. CONCLUSION: In this swine model of witnessed CPR, simulated MTM ventilation was not beneficial for blood gases, gas exchange, or ventilation during ECC or ACD CPR.

Cervical prevertebral soft-tissue measurements and chest radiographic findings in acute traumatic aortic injury.

Acute traumatic aortic injury (ATAI) results in several characteristic chest radiographic findings, most notably mediastinal widening. This study was based on the hypothesis that blood or fluid in the widened mediastinum might track up into the neck and be detected on lateral cervical radiographs. In a blinded, retrospective, case-control review of radiology files, 13 consecutive adult cases of ATAI were identified and compared with 19 cases of negative aortography (NAO) and 18 multiple trauma victims (MT) without aortography. Cases with inadequate cervical films or cervical injury were excluded. Measurements included the cervical soft-tissue (ST) width at the third (C3) and sixth (C6) cervical vertebrae, mediastinal width, mediastinal-chest width ratio, and the presence of several characteristic chest radiograph findings of ATAI. The C3 ST measurements averaged 9.1 +/- 2.8 mm, 8.5 +/- 2.7 mm, and 6.9 +/- 2.2 mm for the ATAI, NAO, and MT groups, respectively. The C6 ST measurements averaged 19.2 +/- 4.5 mm, 18.6 +/- 3.9, and 16.5 +/- 3.8 mm for the ATAI, NAO, and MT groups, respectively. These cervical ST values were not significantly different between groups at either C3 (P = .188) or C6 (P = .148). The incidence of abnormal ST swelling of >7 mm at C3 was 38%, 53%, and 33% for the ATAI, NAO, and MT groups, respectively. The incidence of abnormal ST swelling of >20 mm at C6 was 54%, 42%, and 11% for the ATAI, NAO, and MT groups, respectively. Cervical ST measurements at C3 or at C6 did not correlate with mediastinal-chest width ratios. Mediastinal widening, aortopulmonic window opacification, and blurring of the aortic knob were the most sensitive chest radiography findings in ATAI, although each of these lacked useful specificity and accuracy. Cervical ST swelling is not a useful marker for ATAI.

Shock index as a marker for significant injury in trauma patients.

OBJECTIVE: To determine whether the shock index (SI), defined as the ratio of heart rate (HR) to systolic blood pressure (SBP), is a useful marker for significant injury in trauma patients. METHODS: A retrospective database analysis was used to relate the SI to the clinical measures: death within 24 hours, injury severity score (ISS) > or = 16, intensive care unit (ICU) stay > or = 1 day, and amount of blood transfused (BT) > or = 2 units. Consecutive trauma patients seen at one level I trauma center over a 24-month period were reviewed; excluded were patients not requiring trauma team consultation, or those with either incomplete records, severe head injury (Glasgow Coma Scale score < or = 8), or age < 14 years. The SI was calculated from ED admission vital signs. Receiver operating characteristic (ROC) curves were used to find the value of the SI that maximized the sum of sensitivity and specificity for predicting each measure, separately; a separate analysis was done to determine the optimal SI threshold for predicting any of the severity measures. RESULTS: 1,101 cases met study criteria. The optimal SI values (by ROC analysis) for predicting the severity measures were: 1.10 for death < 24 hours, 0.71 for ISS > or = 16, 0.77 for ICU > or = 1 day, and 0.85 for BT > or = 2 units. The optimal SI value (by ROC analysis) for any of the above measures was 0.83; use of this SI cutoff provided a sensitivity of 37% (95% CI 32-42%), a specificity of 83% (95% CI 80-87%), and a negative predictive value of 58% (95% CI 54-61%) for any measure. This SI threshold predicted between 24% fewer cases and 4% more cases of poor outcome than did the optimal thresholds HR and SBP, respectively. CONCLUSION: The optimal SI threshold performed similarly to the optimal threshold HR or SBP for prediction of injury severity.

Emergency physician use of ultrasonography in blunt abdominal trauma.

OBJECTIVE: To evaluate the diagnostic utility of abdominal diagnostic ultrasonography (DUS) performed by emergency physicians for intraperitoneal fluid caused by blunt abdominal trauma (BAT). METHODS: The design was a prospective, blind, observational study. During a 15-month period, a convenience sample of patients presenting to the ED with BAT necessitating CT scan of the abdomen, diagnostic peritoneal lavage (DPL), or laparotomy was studied. Scans were performed by an emergency medicine (EM) attending, or a resident supervised by an attending, using a real-time sector ultrasound scanner with a 3.5-MHz probe. Training in DUS included a 1-hour didactic session and 1 hour of practice on human volunteers. Free intraperitoneal fluid was defined as an anechoic stripe in the hepatorenal, bladder-rectal, or splenorenal space, and constituted a positive DUS study. Free intraperitoneal fluid detected on abdominal CT scan, DPL, and/or laparotomy was the criterion standard. RESULTS: Of 110 patients scanned, 13 were excluded secondary to technical difficulty or lack of diagnostic follow-up modalities. Of the remaining 97 patients, there were 24 females and 73 males, ranging from ages 2 to 78 years. DUS detected intraperitoneal fluid in 21 subjects, including 3 false positives. There were 6 false-negative DUS examinations. DUS had a sensitivity of 75% (95% CI 53-90%), a specificity 96% of (95% CI 89-99%), and an accuracy of 91% (95% CI 83-96%). No false-positive or false-negative DUS study occurred after the first 67 cases. The mean interval for a DUS scan was 4.9 +/- 2.9 minutes, ranging from 0.5 to 16 minutes, and the mean intervals were not different between the positive and the negative studies. The accuracies of DUS were similar in the pediatric patients, 97% (95% CI 83-100%), and in the adults, 88% (95% CI 78-95%). The hepatorenal view provided the highest sensitivity as well as the least number of uninterpretable scans of the 3 DUS views. CONCLUSION: Emergency physicians with minimal training can use DUS with fair sensitivity and good specificity and accuracy to detect free intraperitoneal fluid in both pediatric and adult BAT victims. The hepatorenal view provides the highest sensitivity for intraperitoneal fluid, although the 3-view series (with hepatorenal, bladder-rectal, and splenorenal spaces) can typically be performed within 5 minutes and may increase the specificity and accuracy.

Intrasound vibration testing in acute ankle injuries.

OBJECTIVES: To determine the accuracy of intrasound vibration testing (IVT) in comparison with plain radiography in the diagnosis of acute ankle fractures. METHODS: A group-sequential, nonrandomized, double-blind, observational study design was used. A convenience sample of patients were studied, aged > or = 10 years, with acute ankle injuries, undergoing ankle radiography, evaluated at a community teaching hospital ED. Excluded were cases involving injuries of > 24 hours' duration, inadequate documentation, protocol violation, or positive IVT on the uninjured ankle. IVT was performed with the intrasound apparatus placed on the anterior and posterior aspects of the medial and lateral malleoli of the uninjured and injured ankles; positive IVT was defined as patient withdrawal secondary to pain. RESULTS: Of 105 patients enrolled, 8 were excluded; 1 for inadequate documentation, 5 for protocol violation, and 2 for positive IVT of the uninjured ankle. Of the 97 patients analyzed, 13 had fractures identified by radiography, including 9 lateral malleolar, 1 medial malleolar, 1 bimalleolar, and 2 talar fractures. Only 5 of the 13 fractures were detected with IVT (sensitivity = 39%; 95% CI: 14-68%). Seventy of 84 nonfractured ankles had negative IVT (specificity = 83%; 95% CI: 74-91%). Of the 19 with positive IVT, 5 had fractures (positive predictive value of 26%; 95% CI: 9-51%). Of the 78 with negative IVT, 70 had no fracture (negative predictive value of 90%; 95% CI: 81-96%). Overall, 75 of 97 IVTs were correct (77%), most of which were among patients without fractures.

Evaluation of capnography in nonintubated emergency department patients with respiratory distress.

OBJECTIVE: To evaluate the ability of noninvasive capnographic measurement of end-tidal CO2 tension (PetCO2) to predict arterial CO2 tension (PaCO2) in nonintubated ED patients with respiratory distress. METHODS: A prospective, nonblind study was performed in a level I trauma center/community teaching hospital ED. Participants included all nonintubated adult patients with respiratory distress requiring measurement of arterial blood gases (ABGs); 29 patients were enrolled. PetCO2 was measured with a capnography monitor, using both baseline tidal volumes and forced expiratory volumes. The bias between PetCO2 values and simultaneous measurements of PaCO2 by ABG was assessed. RESULTS: PetCO2, measured with forced expiration, and PaCO2 agreed well, with bias (i.e., average difference) = 0.44 +/- 0.52 kPa (3.3 +/- 3.9 torr). PetCO2 measured with the tidal volume breath produced an unacceptably high bias of 0.82 +/- 0.70 kPa (6.1 +/- 5.2 torr). Levels of agreement between PaCO2 were similar for smokers and nonsmokers and for men and women. The arterial-end-tidal CO2 tension (Pa-etCO2) difference was not related to PaCO2. Pa-etCO2 correlated with age (r = 0.473; p = 0.01), and was significantly higher in patients with pulmonary disease (1.32 +/- 0.56 kPa; 9.9 +/- 4.2 torr) than it was in those without pulmonary disease (0.46 +/- 0.55 kPa; 3.5 +/- 4.1 torr; p < 0.001). CONCLUSIONS: Noninvasive PetCO2 monitoring may adequately predict PaCO2 in nonintubated ED patients with respiratory distress who are able to produce a forced expiration. PetCO2 is less accurate for PaCO2 with tidal volume breathing and in patients with pulmonary disease.

Hematologic safety of intraosseous blood transfusion in a swine model of pediatric hemorrhagic hypovolemia.

OBJECTIVE: To assess the risk of hemolysis, disseminated intravascular coagulation (DIC), or fat embolism syndrome (FES) with pressurized intraosseous (IO) blood transfusion following hemorrhage. METHODS: A controlled, repeated-measures, randomized animal study with blinded pathologic evaluations was conducted. Sixteen pentobarbital-anesthetized, instrumented immature swine underwent a 20-mL/kg hemorrhage into citrate-phosphate-dextrose bags, then received autologous blood transfusion via a 16-ga i.v. catheter (eight), or via a 15-ga IO needle in the proximal tibia (eight) under maximal manual pressure using a 30-mL syringe. At baseline and at one hour and 48 hours posttransfusion, blood samples were assayed for hemoglobin (Hb), schistocytes, free Hb in plasma, bilirubin, lactate dehydrogenase, platelets, fibrinogen, and alveolar-arteriolar O2 gradient. Lung sections were examined for inflammation after hematoxylin/eosin stain, and for fat emboli after oil red-O-stain. Kidney sections were examined for inflammation using hematoxylin/eosin stain. RESULTS: Though the IO transfusion rate of 21 +/- 6 mL/min was slower than the i.v. rate of 35 +/- 5 mL/min (p = 0.0012), all the animals returned to baseline blood pressure within 15 minutes and survived. The presence of schistocytes and mildly elevated free Hb in plasma was noted in both groups at baseline and each time period, and was presumed to be due to sampling from the arterial catheter. All other laboratory values remained within normal limits and without intergroup differences at any time period. No fat embolus was noted, and all lung and kidney specimens were free of inflammation. CONCLUSIONS: In this model, pressurized IO blood transfusion appears to be hematologically safe, i.e., without risk of appreciable hemolysis, DIC, or FES.

Delayed tension pneumothorax complicating central venous catheterization and positive pressure ventilation.

Pneumothorax is the most common complication after central venous catheterization. The diagnosis of pneumothorax may be delayed for hours or days, in some instances because of minimal clinical symptoms or radiographic signs on initial evaluation, or in other instances because of late presentation precipitated by positive pressure ventilation. A case is presented in which a patient developed a tension pneumothorax while under general anesthesia 10 days after central venous line placement. A review of the literature suggests that delayed pneumothorax has an incidence of approximately 0.4% of all central venous access attempts, is much more common after subclavian than internal jugular approaches, especially in difficult or multiple attempts, is asymptomatic in 22%, and results in tension pneumothorax in 22%. End-expiratory upright chest radiographs, the optimal radiographic technique for detection of small pneumothoraces, were obtained in only 19% of reviewed cases. Supine views, the least sensitive radiographic technique, should be carefully reviewed for evidence of basilar hyperlucency, a deep sulcus sign, or a double diaphragm sign. In patients unable to tolerate the upright position, supine views should be supplemented with lateral decubitus, oblique, or cross-table lateral views. Emergency physicians should be aware of the possibility of delayed pneumothorax, as well as optimal radiographic technique for demonstration of small pneumothoraces, and subtle radiographic findings in supine or semirecumbent patients.

Benign cervical prevertebral soft tissue swelling in traumatic asphyxia.

Two cases of benign cervical prevertebral soft tissue swelling following traumatic asphyxia are presented. Neither were associated with neck pain, neck tenderness, or mechanism of injury associated with cervical injury, and each resolved spontaneously. Traumatic asphyxia, which results in significant craniofacial swelling, may also result in swelling of the retropharyngeal soft tissues, which may be detected on cervical radiography. Cervical prevertebral soft tissue swelling in the setting of traumatic asphyxia should not be misinterpreted as suggestive of spinal injury in the absence of other findings.

Hemodynamic effects of 3,4-diaminopyridine in a swine model of verapamil toxicity.

STUDY HYPOTHESIS: 3,4-Diaminopyridine (3,4-DAP) may reverse the hemodynamic effects of severe verapamil toxicity. DESIGN: A nonblinded acute animal preparation. INTERVENTIONS: Eighteen chloralose-anesthetized and instrumented swine were poisoned with verapamil at 10 mg/kg/hr for five minutes and then 5 mg/kg/hr until a systolic blood pressure of 55 mm Hg was achieved. Heart rate, lead II ECG, mean arterial pressure, left ventricular dP/dT max, and cardiac index were monitored. Nine control animals received 0.2 mL/kg/min infusion of normal saline, and nine treatment animals received similar volumes of 1 mg/kg/min 3,4-DAP until systolic blood pressure reached 100 mm Hg, an elapsed time of 30 minutes, or death. RESULTS: Verapamil toxicity was produced in all animals following an average dose of 1.38 +/- 0.44 mg/kg verapamil, and resulted in diminished mean arterial pressure, dP/dT max, cardiac index, and heart rate to average values of 47%, 32%, 46%, and 88% of baseline values, respectively. Transient atrioventricular dissociation was noted in only 22% of cases. 3,4-DAP treatment (with an average dose of 14 +/- 5.6 mg/kg) resulted in significant increases in mean arterial pressure, dP/dT max, cardiac index, and heart rate to 136%, 298%, 149%, and 158% of baseline values, respectively. Mortality was unchanged (22% in both groups). 3,4-DAP treatment was complicated by muscle twitching, tachycardia (rate of more than 180) and hypertension (diastolic blood pressure of more than 110 mm Hg) each in 44% of cases. CONCLUSION: Although 3,4-DAP reversed the hypotensive and negative inotropic effects of verapamil toxicity, it failed to improve survival and resulted in several complications including muscle twitching, tachycardia, and hypertension.

Compliance with emergency department referral: the effect of computerized discharge instructions.

STUDY OBJECTIVE: To examine the effect of computerized discharge instructions on emergency department patient referral recommendations. DESIGN: Prospective, descriptive analysis and clinical trial. SETTING: Emergency medicine residency-affiliated urban hospital with 568 beds and 29,000 annual visits. TYPE OF PARTICIPANTS: One thousand ED patients discharged to an outpatient referral network during a six-week period. INTERVENTION: Mandatory referral was provided in written or computerized (Logicare Corp, Eau Claire, Wisconsin) format for each 500-patient group. Demographic data and compliance, measured as appointment completion within 30 days, were analyzed using chi 2 with Yates' correction, Fisher's exact, and odds ratio comparisons (P < .05, 95% confidence interval). MEASUREMENTS AND MAIN RESULTS: The institution of computerized discharge instructions resulted in increased overall patient compliance from 26.2% to 36.2% (P < .0008) with odds ratio of 1.59 (1.2 to 2.1). Subset analysis showed increased compliance in patients who were more than 40 years old (32.5% to 61.1%), were female (28.7% to 39.7%) with a private physician (36.4% to 53.9%), established hospital relationship (26.1% to 38.9%), had nonurgent complaints (26.5% to 36.2%), were specifically diagnosed with strain or contusion (17.0% to 36.8%), or were referred to obstetrics/gynecology clinic (13.2% to 48.6%) (P < .001). CONCLUSION: Computerized discharge instructions were associated with improved compliance with ED referral recommendations, based on historic and contemporary controls.

Emergency abdominal radiography.

Plain abdominal radiographs are rarely diagnostic when the patient presents with acute abdominal pain. Emergency physicians, therefore, should be aware of the appropriate indications and limitations of abdominal films in this setting and should be skilled in their interpretation to exclude the rare cases of pneumoperitoneum, pneumobilia, hepatic-portovenous gas, small and large bowel obstruction, toxic megacolon, volvulus and intramural gas.

An evaluation of cannulae and oxygen sources for pediatric jet ventilation.

The authors evaluated the cannulae and oxygen sources available for pediatric translaryngeal ventilation. Peak flow rates were measured and maximum tidal volumes (MTV) calculated for each combination of cannula and oxygen source. Standard 22, 20, 18, and 16 gauge intravenous catheters and a 14 gauge cannula designed for pediatric jet ventilation were tested. The oxygen sources evaluated included an adult bag-valve device; a continuous flow source regulated between 6 to 15 L/min; and a high pressure jet source regulated between 5 to 50 psi. Mean calculated MTV delivered to the cannula tip (22 g to 14 g) were: 26 to 235 mL with the bag-valve source; 91 to 236 mL with the continuous flow sources; and 58 to 1034 mL with the jet sources. Assuming that in normal subjects approximately 70% of the flow from the tip of a translaryngeal cannula reaches the distal respiratory tree, the authors conclude that bag-valve and continuous flow low pressure sources are unlikely to deliver sufficient tidal volumes to sustain normal ventilation in apneic children when coupled with standard cannulae. Jet oxygen sources with standard cannulae provide a wide range of tidal volumes sufficient to sustain normal ventilation in apneic pediatric patients.