Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer

BACKGROUND

The limitations of the current diagnostic standard, ventilation-perfusion lung scanning, complicate the management of patients with suspected pulmonary embolism. We previously demonstrated that determining the pretest probability can assist with management and that the high negative predictive value of certain D -dimer assays may simplify the diagnostic process.

OBJECTIVE

To determine the safety of using a simple clinical model combined with D -dimer assay to manage patients presenting to the emergency department with suspected pulmonary embolism.

DESIGN

Prospective cohort study.

SETTING

Emergency departments at four tertiary care hospitals in Canada.

PATIENTS

930 consecutive patients with suspected pulmonary embolism.

INTERVENTIONS

Physicians first used a clinical model to determine patients' pretest probability of pulmonary embolism and then performed a D -dimer test. Patients with low pretest probability and a negative D -dimer result had no further tests and were considered to have a diagnosis of pulmonary embolism excluded. All other patients underwent ventilation-perfusion lung scanning. If the scan was nondiagnostic, bilateral deep venous ultrasonography was done. Whether further testing (by serial ultrasonography or angiography) was done depended on the patients' pretest probability and the lung scanning results.

MEASUREMENTS

Patients received a diagnosis of pulmonary embolism if they had a high-probability ventilation-perfusion scan, an abnormal result on ultrasonography or pulmonary angiography, or a venous thromboembolic event during follow-up. Patients for whom the diagnosis was considered excluded were followed up for 3 months for the development of thromboembolic events.

RESULTS

The pretest probability of pulmonary embolism was low, moderate, and high in 527, 339, and 64 patients (1.3%, 16.2%, and 37.5% had pulmonary embolism), respectively. Of 849 patients in whom a diagnosis of pulmonary-embolism had initially been excluded, 5 (0.6% [95% CI, 0.2% to 1.4%]) developed pulmonary embolism or deep venous thrombosis during follow-up. However, 4 of these patients had not undergone the proper diagnostic testing protocol. In 7 of the patients who received a diagnosis of pulmonary embolism, the physician had performed more diagnostic tests than were called for by the algorithm. In 759 of the 849 patients in whom pulmonary embolism was not found on initial evaluation, the diagnostic protocol was followed correctly. Only 1 (0.1% [CI, 0.0% to 0.7%]) of these 759 patients developed thromboembolic events during follow-up. Of the 437 patients with a negative D -dimer result and low clinical probability, only 1 developed pulmonary embolism during follow-up; thus, the negative predictive value for the combined strategy of using the clinical model with D -dimer testing in these patients was 99.5% (CI, 99.1% to 100%).

CONCLUSION

Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.

Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer

BACKGROUND

The limitations of the current diagnostic standard, ventilation-perfusion lung scanning, complicate the management of patients with suspected pulmonary embolism. We previously demonstrated that determining the pretest probability can assist with management and that the high negative predictive value of certain D -dimer assays may simplify the diagnostic process.

OBJECTIVE

To determine the safety of using a simple clinical model combined with D -dimer assay to manage patients presenting to the emergency department with suspected pulmonary embolism.

DESIGN

Prospective cohort study.

SETTING

Emergency departments at four tertiary care hospitals in Canada.

PATIENTS

930 consecutive patients with suspected pulmonary embolism.

INTERVENTIONS

Physicians first used a clinical model to determine patients' pretest probability of pulmonary embolism and then performed a D -dimer test. Patients with low pretest probability and a negative D -dimer result had no further tests and were considered to have a diagnosis of pulmonary embolism excluded. All other patients underwent ventilation-perfusion lung scanning. If the scan was nondiagnostic, bilateral deep venous ultrasonography was done. Whether further testing (by serial ultrasonography or angiography) was done depended on the patients' pretest probability and the lung scanning results.

MEASUREMENTS

Patients received a diagnosis of pulmonary embolism if they had a high-probability ventilation-perfusion scan, an abnormal result on ultrasonography or pulmonary angiography, or a venous thromboembolic event during follow-up. Patients for whom the diagnosis was considered excluded were followed up for 3 months for the development of thromboembolic events.

RESULTS

The pretest probability of pulmonary embolism was low, moderate, and high in 527, 339, and 64 patients (1.3%, 16.2%, and 37.5% had pulmonary embolism), respectively. Of 849 patients in whom a diagnosis of pulmonary-embolism had initially been excluded, 5 (0.6% [95% CI, 0.2% to 1.4%]) developed pulmonary embolism or deep venous thrombosis during follow-up. However, 4 of these patients had not undergone the proper diagnostic testing protocol. In 7 of the patients who received a diagnosis of pulmonary embolism, the physician had performed more diagnostic tests than were called for by the algorithm. In 759 of the 849 patients in whom pulmonary embolism was not found on initial evaluation, the diagnostic protocol was followed correctly. Only 1 (0.1% [CI, 0.0% to 0.7%]) of these 759 patients developed thromboembolic events during follow-up. Of the 437 patients with a negative D -dimer result and low clinical probability, only 1 developed pulmonary embolism during follow-up; thus, the negative predictive value for the combined strategy of using the clinical model with D -dimer testing in these patients was 99.5% (CI, 99.1% to 100%).

CONCLUSION

Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.

Vasopressin versus epinephrine for inhospital cardiac arrest: a randomised controlled trial

BACKGROUND

Survival rates for cardiac arrest patients, both in and out of hospital, are poor. Results of a previous study suggest better outcomes for patients treated with vasopressin than for those given epinephrine, in the out-of-hospital setting. Our aim was to compare the effectiveness and safety of these drugs for the treatment of in-patient cardiac arrest.

METHODS

We did a triple-blind randomised trial in the emergency departments, critical care units, and wards of three Canadian teaching hospitals. We assigned adults who had cardiac arrest and required drug therapy to receive one dose of vasopressin 40 U or epinephrine 1 mg intravenously, as the initial vasopressor. Patients who failed to respond to the study intervention were given epinephrine as a rescue medication. The primary outcomes were survival to hospital discharge, survival to 1 h, and neurological function. Preplanned subgroup assessments included patients with myocardial ischaemia or infarction, initial cardiac rhythm, and age.

FINDINGS

We assigned 104 patients to vasopressin and 96 to epinephrine. For patients receiving vasopressin or epinephrine survival did not differ for hospital discharge (12 [12%] vs 13 [14%], respectively; p50.67; 95% CI for absolute increase in survival 211.8% to 7.8%) or for 1 h survival (40 [39%] vs 34 [35%]; p50.66; 210.9% to 17.0%); survivors had closely similar median mini-mental state examination scores (36 [range 19-38] vs 35 [20-40]; p50.75) and median cerebral performance category scores (1 vs 1).

INTERPRETATION

We failed to detect any survival advantage for vasopressin over epinephrine. We cannot recommend the routine use of vasopressin for inhospital cardiac arrest patients, and disagree with American Heart Association guidelines, which recommend vasopressin as alternative therapy for cardiac arrest.

Acebutolol-induced ventricular tachycardia reversed with sodium bicarbonate

BACKGROUND

Acebutolol is a unique beta blocker that possesses cardioselectivity, partial agonist activity, and membrane stabilizing activity. Sodium bicarbonate is used to reverse the cardiotoxic effects of other drugs with membrane stabilizing activity. There have been no reported cases of acebutolol-induced ventricular dysrhythmias treated successfully with bolus sodium bicarbonate.

CASE PRESENTATION

A 48-year-old man ingested approximately 6.4 g of acebutolol with ethanol (blood ethanol 61 mmol/L). There were no other coingestants identified. One hour after presentation, the patient had a cardiac arrest with the monitor showing ventricular tachycardia. Sodium bicarbonate 50 mEq intravenous push converted the patient to sinus rhythm and the blood pressure improved to 129/90 mm Hg.

CONCLUSION

This case demonstrates a temporal relationship between bolus sodium bicarbonate administration and the termination of acebutolol-induced ventricular tachycardia.

The Ontario trial of active compression-decompression cardiopulmonary resuscitation for in-hospital and prehospital cardiac arrest

OBJECTIVE

To compare the impact of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) and standard CPR on the outcomes of in-hospital and prehospital victims of cardiac arrest.

DESIGN

Randomized controlled trial with blinding of allocation using a sealed container.

SETTINGS

(1) Emergency departments, wards, and intensive care units of 5 university hospitals and (2) all locations outside hospitals in 2 midsized cities.

PATIENTS

A total of 1784 adults who had cardiac arrest.

INTERVENTION

Patients received either standard or ACD CPR throughout resuscitation.

MAIN OUTCOME MEASURES

Survival for 1 hour and to hospital discharge and the modified Mini-Mental State Examination (MMSE).

RESULTS

All characteristics were similar in the standard and ACD CPR groups for the 773 in-hospital patients and the 1011 prehospital patients. For in-hospital patients, there were no significant differences between the standard (n = 368) and ACD (n = 405) CPR groups in survival for 1 hour (35.1% vs 34.6%; P = .89), in survival until hospital discharge (11.4% vs 10.4%; P = .64), or in the median MMSE score of survivors (37 in both groups). For patients who collapsed outside the hospital, there were also no significant differences between the standard (n = 510) and ACD (n = 501) CPR groups in survival for 1 hour (16.5% vs 18.2%; P = .48), in survival to hospital discharge (3.7% vs 4.6%; P = .49), or in the median MMSE score of survivors (35 in both groups). Exploration of clinically important subgroups failed to identify any patients who appeared to benefit from ACD CPR.

CONCLUSIONS

ACD CPR did not improve survival or neurologic outcomes in any group of patients with cardiac arrest.

Cardiac arrest in Ontario: circumstances, community response, role of prehospital defibrillation and predictors of survival

OBJECTIVES

To describe the patient characteristics, circumstances and community response in cases of out-of-hospital cardiac arrest; to evaluate the effect on survival of the introduction of prehospital defibrillation; and to identify factors that predict survival.

DESIGN

Population-based before-and-after clinical trial.

SETTING

Five Ontario communities: London, Sudbury, the Greater Niagara region, Kingston and Ottawa.

PATIENTS

A consecutive sample of 1510 primary cardiac arrest patients who were transported to hospital by ambulance over 2 years.

INTERVENTION

The use of defibrillators by ambulance attendants.

MAIN OUTCOME MEASURES

Patient characteristics (sex and age), circumstances of arrest (place, whether arrest was witnessed and cardiac rhythm), citizen response (whether cardiopulmonary resuscitation [CPR] was started by a bystander, time to access to emergency medical services and time to initiation of CPR), emergency medical services response (ambulance response time, time to initiation of CPR and time to rhythm analysis with defibrillator) and survival rates.

MAIN RESULTS

A total of 92.1% of the patients were 50 years of age or older, and 68.3% were men. Overall, 79.6% of the arrests occurred in the home. The average ambulance response time for witnessed cases was 7.8 minutes. The overall survival rate was 2.5%. The survival rates before and after defibrillators were introduced were similar, and the general functional outcome of the survivors did not differ significantly between the two phases. Factors predicting survival included patient's age, ambulance response time and whether CPR was started before the ambulance arrived.

CONCLUSIONS

The survival rate was lower than expected. The availability of prehospital defibrillation did not affect survival. To improve survival rates after cardiac arrest ambulance response times must be reduced and the frequency of bystander-initiated CPR increased. Once these changes are in place a beneficial effect from advanced manoeuvres such as prehospital defibrillation may be seen.

Hydatid cyst of the pancreatic tail. A case report

A case of calcified hydatid cyst of the pancreatic tail is presented. The ultrasonographic and computed tomographic features of the lesion suggested the presence of a cystadenoma or a calcified hydatid cyst. Computed tomography proved the most useful investigation and accurately localized the lesion. A distal pancreatectomy and splenectomy were performed because on the basis of the results of pre-operative investigations and macroscopic operative findings, carcinoma of the pancreatic tail could not be ruled out with certainty. The patient made an uneventful recovery.