Thomas O. Stair

Effects of morphine analgesia on diagnostic accuracy in emergency department patients with abdominal pain: a prospective, randomized trial ☆

BACKGROUND Because of concerns about masking important physical findings, there is controversy surrounding whether it is safe to provide analgesia to patients with undifferentiated abdominal pain. The purpose of this study was to address the effects of analgesia on the physical examination and diagnostic accuracy for patients with abdominal pain. STUDY DESIGN The study was a prospective, double-blind clinical trial in which adult Emergency Department (ED) patients with undifferentiated abdominal pain were randomized to receive placebo (control group, n = 36) or morphine sulphate (MS group, n = 38). Diagnostic and physical examination assessments were recorded before and after a 60-minute period during which study medication was titrated. Diagnostic accuracy and physical examination changes were compared between groups using univariate statistical analyses. RESULTS There were no differences between control and MS groups with respect to changes in physical or diagnostic accuracy. The overall likelihood of change in severity of tenderness was similar in MS (37.7%) as compared with control (35.3%) patients (risk ratio [RR] 1.07, 95% confidence interval [CI] 0.64-1.78). MS patients were no more likely than controls to have a change in pain location (34.0% versus 41.2%, RR 0.82, 95% CI 0.50-1.36). Diagnostic accuracy did not differ between MS and control groups (64.2% versus 66.7%, RR 0.96, 95% CI 0.73-1.27). There were no differences between groups with respect to likelihood of any change occurring in the diagnostic list (37.7% versus 31.4%, RR 1.20, 95% CI 0.71-2.05). Correlation with clinical course and final diagnosis revealed no instance of masking of physical examination findings. CONCLUSIONS Results of this study support a practice of early provision of analgesia to patients with undifferentiated abdominal pain.

SMART—An Integrated Wireless System for Monitoring Unattended Patients

Monitoring vital signs and locations of certain classes of ambulatory patients can be useful in overcrowded emergency departments and at disaster scenes, both on-site and during transportation. To be useful, such monitoring needs to be portable and low cost, and have minimal adverse impact on emergency personnel, e.g., by not raising an excessive number of alarms. The SMART (Scalable Medical Alert Response Technology) system integrates wireless patient monitoring (ECG, SpO(2)), geo-positioning, signal processing, targeted alerting, and a wireless interface for caregivers. A prototype implementation of SMART was piloted in the waiting area of an emergency department and evaluated with 145 post-triage patients. System deployment aspects were also evaluated during a small-scale disaster-drill exercise.

Physiological signal monitoring in the waiting areas of an emergency room

The Scalable Medical Alert and Response Technology (SMART) System was developed to monitor physiological signals from patients in the waiting areas of an emergency department. The system monitors the SpO2 (oxygenation level in the blood), ECG (electrical activity of the heart) and the location of multiple patients wirelessly. It was deployed at the Brigham and Womens Hospital in Boston, MA, between June, 2006, and December, 2007. This paper describes the overall architecture, the sensors used, challenges in deploying this technology in a hospital and the degree of patient acceptance. Some sections of this article are based on an article first published in the Journal of the American Medical Informatics Association (J Am Med Inform Assn: 2008; 1) [7].

Adenosine for wide-complex tachycardia: Efficacy and safety*

Objectives:To determine whether adenosine is useful and safe as a diagnostic and therapeutic agent for patients with undifferentiated wide QRS complex tachycardia. The etiology of sustained monomorphic wide QRS complex tachycardia is often uncertain acutely. Design:A retrospective observational study. Setting:Treatment associated with emergency visits at nine urban hospitals. Patients:Consecutive patients treated with adenosine for regular wide QRS complex tachycardia between 1991 and 2006. Interventions:Treatment with adenosine infusion. Measurements and Main Results:Measured outcomes included rhythm response to adenosine, if any, and all adverse effects. A positive response was defined as an observed change in rhythm including temporary atrioventricular conduction block or tachycardia termination. A primary adverse event was defined as emergent electrical or medical therapy instituted in response to an adverse adenosine effect. A rhythm diagnosis was made in each case. The characteristics of adenosine administration as a test for a supraventricular as opposed to ventricular tachycardia were determined, and the adverse event rates were calculated. A total of 197 patients were included: 104 (90%) of 116 (95% confidence interval, 83%–95%) and two (2%) of 81 (95% confidence interval, 0.3%–9%) supraventricular tachycardia and ventricular tachycardia patients demonstrated a response to adenosine, respectively. The odds of supraventricular tachycardia increased by a factor of 36 (95% confidence interval, 9–143) after a positive response to adenosine. The odds of ventricular tachycardia increased by a factor of 9 (95% confidence interval, 6–16) when there was no response to adenosine. The rate of primary adverse events for patients with supraventricular tachycardia and ventricular tachycardia was 0 (0%) of 116 (95% confidence interval, 0%–3%) and 0 (0%) of 81 (95% confidence interval, 0%–4%), respectively. Conclusions:Adenosine is useful and safe as a diagnostic and therapeutic agent for patients with regular wide QRS complex tachycardia.

Amiodarone or Procainamide for the Termination of Sustained Stable Ventricular Tachycardia: An Historical Multicenter Comparison

OBJECTIVES The objective was to compare the effectiveness of intravenous (IV) procainamide and amiodarone for the termination of spontaneous stable sustained ventricular tachycardia (VT). METHODS A historical cohort study of consecutive adult patients with stable sustained VT treated with IV amiodarone or procainamide was performed at four urban hospitals. Patients were identified for enrollment by admissions for VT and treatment with the study agents in the emergency department (ED) from 1993 to 2008. The primary measured outcome was VT termination within 20 minutes of onset of study medicine infusion. A secondary effectiveness outcome was the ultimate need for electrical therapy to terminate the VT episode. Major adverse effects were tabulated, and blood pressure responses to medication infusions were compared. RESULTS There were 97 infusions of amiodarone or procainamide in 90 patients with VT, but the primary outcome was unknown after 14 infusions due to administration of another antidysrhythmic during the 20-minute observation period. The rates of VT termination were 25% (13/53) and 30% (9/30) for amiodarone and procainamide, respectively. The adjusted odds of termination with procainamide compared to amiodarone was 1.2 (95% confidence interval [CI]=0.4 to 3.9). Ultimately, 35/66 amiodarone patients (53%, 95% CI=40 to 65%) and 13/31 procainamide patients (42%, 95% CI=25 to 61%) required electrical therapy for VT termination. Hypotension led to cessation of medicine infusion or immediate direct current cardioversion (DCCV) in 4/66 (6%, 95% CI=2 to 15%) and 6/31 (19%, 95% CI=7 to 37%) patients who received amiodarone and procainamide, respectively. CONCLUSIONS Procainamide was not more effective than amiodarone for the termination of sustained VT, but the ability to detect a significant difference was limited by the study design and potential confounding. As used in practice, both agents were relatively ineffective and associated with clinically important proportions of patients with decreased blood pressure.

Distributed pervasive services using group service communication supporting body area networks

Body Area Network (BAN) provide critical data in healthcare monitoring environments, where such monitoring can be performed in a ubiquitous manner using various miniature device technologies. However, a key requirement in supporting the full capacity of a BAN is an efficient distribution, processing and application of the acquired data. The architecture and applications which capitalize on the huge potential of this data, provide significant added value to BANs. This paper proposes an architecture which is service oriented and integrates the data produced by BANs into a healthcare environment, supporting remote interactions between medical officers to maximise patient care. The dynamic interaction of distributed services in this diverse environment is a key ingredient in the way technology can enhance healthcare. The architecture defines group services which facilitate the control of the dynamic behaviour of services within this heterogeneous environment.

Adding the Human Element: Experience with a Wireless Patient Monitoring System

This chapter describes how the design and deployment of a wireless sensor network for patient monitoring was affected by human factors. The wireless sensor network was deployed and studied in the waiting area of an emergency department at an urban academic hospital in the United States. The broader application of this work is in the area of disaster management. The challenges were in the integration of this new technology into a pre-existing environment for caring for patients with minimal disruption. These challenges included operation restrictions mandated by the hospital’s Institutional Review Board, choice of an appropriate localization subsystem, limited power, concerns about fire hazards, theft, and hospital security during the eighteen-month deployment. Issues such as user acceptance, patient mobility and expectations of multiple stake holders are also discussed.