Undersensing of VF in a Patient With Optimal R Wave Sensing During Sinus Rhythm

We describe a case of potentially fatal undersensing of VF by a third generation ICD with predetermined automatic gain control. In this patient, ventricular sensing was optimal, as R wave amplitudes during sinus rhythm were at least 16 mV. Cyclical, high amplitude signals during VF elevated the sensing floor to such an extent that complete undersensing of subsequent lower amplitude local electrograms occurred. This led to bradypacing and complete ICD therapy failure. Therefore, high R wave amplitudes during sinus rhythm do not warrant flawless sensing during VF. (PACE 2004; 27[Pt. I] 833–834)     

Non-prescribed drug use during methadone treatment by clinic- and community-based patients

We investigated the efficacy of methadone maintenance treatment in clinic-based (n= 10) and community-based (n= 10) patients by studying the relationships between dose, plasma concentrations of methadone and non-prescribed drug-use using logistic regression. We found that clinic-based patients had significantly reduced odds of having a urine sample test positive for illicit drugs when compared to community-based patients (OR = 0.20; 95% confidence interval 0.10–0.38: p < 0.001). There was no relationship between either methadone dose or plasma methadone concentration and testing positive for non-prescribed drugs (including cocaine, cannabis, amphetamine, ecstasy, benzodiazepines). We looked specifically at the misuse of opiate drugs. Location was again important and clinic-based patients had significantly reduced odds of having a urine sample test positive for opiate drugs (OR= 0.36, 95% confidence internal 0.13–0.71: p～0.004). Opiate drug use in our patients was also significantly related to plasma methadone concentration, increasing noticeably when the drug concentration < 0.48 nmol/L (p～0.04). We found no relationship between methadone dose and odds of having a positive urine drug test in either clinic- or community-based patients.     

THE [LACTATE]/[PYRUVATE] RATIO AND ALCOHOL METABOLISM: EXPERIMENTS WITH NALOXONE IN FASTING NORMAL MALE VOLUNTEERS

Naloxone administration to fasting normal male volunteers reversesthe acute ethanol-induced increase in the blood [lactate]/[pyruvate]ratio, but fails to lower blood-ethanol concentration. The resultsare discussed in relation to factors affecting ethanol eliminationand the mechanism of antagonism of acute alcohol intoxicationby naloxone.     

FENTANYL-DROPERIDOL SUPPLEMENTATION OF RAPID SEQUENCE INDUCTION IN THE PRESENCE OF SEVERE PREGNANCY-INDUCED AND PREGNANCY-AGGRAVATED HYPERTENSION

Twenty-six patients manifesting severe pregnancy-induced (PIH)or pregnancy-aggravated (PAH) hypertension who presented foremergency Caesarean section under general anaesthesia were studied.All patients came from a previously identified high risk group—namely> 25 yr, multiparous and with diastolic arterial pressuressustained at > 120 mm Hg. Our standard accelerated inductiontechnique for the management of severely hypertensive motherswas modified to include the use of fentanyl and droperidol beforeinduction. This modification of the induction sequence produceda clinically significant amelioration of the reflex sympathetichypertensive response to laryngoscopy and intubation in mostmothers receiving antihypertensive therapy, without apparentdeleterious effect in the immediate postoperative period tothose neonates unaffected by intrauterine asphyxia. ^*Present addresses: Shackleton Department of Anaesthetics, LevelE, Centre Block, Southampton General Hospital, Southampton SO94XY. University Department of Anaesthesia, Queens Medical Centre,University of Nottingham, Nottingham.     

A Modified Spectrophotometric Method Appropriate for Measuring Cholinesterase Activity in Tissue from Carbaryl-Treated Animals

Inhibited cholinesterase in tissues of animals exposed to carbamatepesticides is known to reactivate readily, presenting considerableproblems in the accurate assessment of cholinesterase activityin these tissues. Decarbamylation of cholinesterase is favoredwhen the tissue samples are diluted and/or are incubated foran extended time. The present study was performed to identifymodifications of the commonly used spectrophotometric assayfor cholinesterase activity that would minimize spontaneousreactivation of enzyme activity. Those modifications includedpreincubation of concentrated tissue with concentrated chromogen(i.e., DTNB), dilution to final reaction volume immediatelybefore measurement, and measurement of cholinesterase over ashort period of time (5–10 min). The Ellman assay withand without modifications was performed using a microtiter platereader on tissues from carbaryl-treated rats: undiluted plasma,diluted erythrocytes (1:25), minimally diluted erythrocytes(1:2), diluted brain (1:100), or minimally diluted brain (1:2).The results were compared to cholinesterase activities obtainedusing a radiometnic method which employs minimally diluted tissueand short incubation times. The degree of cholinesterase inhibitionfor undiluted or minimally diluted tissue assayed by the modifiedmethod agreed with those obtained using the radiometric method.Even if the tissues were diluted immediately before assay, however,significant reactivation occurred by the time the first measurementswere made by the conventional method. Furthermore, significantspontaneous reactivation may still occur using the modifiedmethod if the assay is run for more than 10 min. Use of thismodified Ellman method will enable more accurate estimationof in vivo cholinesterase activity in animals treated with carbamates.     

The Nominal Group Technique: A Research Tool for General Practice?

Qualitative methods are increasingly recognized as valuable,yet practitioners face difficult decisions in their choice ofmethod and the process of analysis. The nominal group techniquecombines quantitative and qualitative data collection in a groupsetting, and avoids problems of group dynamics associated withother group methods such as brainstorming, Delphi and focusgroups. Idea generation and problem solving are combined ina structured group process, which encourages and enhances theparticipation of group members. The stages involved in conductinga nominal group are described, and practical problems of itsuse in a health care setting are discussed with reference toa study of the priorities of care of diabetic patients, carersand health professionals. Some potential applications of thetechnique in audit and exploratory research are also outlined.     

Social Media and Internet‐Based Data in Global Systems for Public Health Surveillance: A Systematic Review

Context: The exchange of health information on the Internet has been heralded as an opportunity to improve public health surveillance. In a field that has traditionally relied on an established system of mandatory and voluntary reporting of known infectious diseases by doctors and laboratories to governmental agencies, innovations in social media and so-called user-generated information could lead to faster recognition of cases of infectious disease. More direct access to such data could enable surveillance epidemiologists to detect potential public health threats such as rare, new diseases or early-level warnings for epidemics. But how useful are data from social media and the Internet, and what is the potential to enhance surveillance? The challenges of using these emerging surveillance systems for infectious disease epidemiology, including the specific resources needed, technical requirements, and acceptability to public health practitioners and policymakers, have wide-reaching implications for public health surveillance in the 21st century.Methods: This article divides public health surveillance into indicator-based surveillance and event-based surveillance and provides an overview of each. We did an exhaustive review of published articles indexed in the databases PubMed, Scopus, and Scirus between 1990 and 2011 covering contemporary event-based systems for infectious disease surveillance.Findings: Our literature review uncovered no event-based surveillance systems currently used in national surveillance programs. While much has been done to develop event-based surveillance, the existing systems have limitations. Accordingly, there is a need for further development of automated technologies that monitor health-related information on the Internet, especially to handle large amounts of data and to prevent information overload. The dissemination to health authorities of new information about health events is not always efficient and could be improved. No comprehensive evaluations show whether event-based surveillance systems have been integrated into actual epidemiological work during real-time health events.Conclusions: The acceptability of data from the Internet and social media as a regular part of public health surveillance programs varies and is related to a circular challenge: the willingness to integrate is rooted in a lack of effectiveness studies, yet such effectiveness can be proved only through a structured evaluation of integrated systems. Issues related to changing technical and social paradigms in both individual perceptions of and interactions with personal health data, as well as social media and other data from the Internet, must be further addressed before such information can be integrated into official surveillance systems.