Nurse initiated thrombolysis in the accident and emergency department: safe, accurate, and faster than fast track.

OBJECTIVE: To reduce the time between arrival at hospital of a patient with acute myocardial infarction and administration of thrombolytic therapy (door to needle time) by the introduction of nurse initiated thrombolysis in the accident and emergency department. METHODS: Two acute chest pain nurse specialists (ACPNS) based in A&E for 62.5 hours of the week were responsible for initiating thrombolysis in the A&E department. The service reverts to a "fast track" system outside of these hours, with the on call medical team prescribing thrombolysis on the coronary care unit. Prospectively gathered data were analysed for a nine month period and a head to head comparison made between the mean and median door to needle times for both systems of thrombolysis delivery. RESULTS: Data from 91 patients were analysed; 43 (47%) were thrombolysed in A&E by the ACPNS and 48 (53%) were thrombolysed in the coronary care unit by the on call medical team. The ACPNS achieved a median door to needle time of 23 minutes (IQR=17 to 32) compared with 56 minutes (IQR=34 to 79.5) for the fast track. The proportion of patients thrombolysed in 30 minutes by the ACPNS and fast track system was 72% (31 of 43) and 21% (10 of 48) respectively (difference=51%, 95% confidence intervals 34% to 69%, p<0.05). CONCLUSION: Diagnosis of acute myocardial infarction and administration of thrombolysis by experienced cardiology nurses in A&E is a safe and effective strategy for reducing door to needle times, even when compared with a conventional fast track system.

Severe pneumococcal pneumonia in previously healthy children: the role of preceding influenza infection.

An outbreak of severe pneumococcal pneumonia among children occurred in Iowa from November 1995 through January 1996. An associated outbreak of influenza disease was predominantly caused by influenza A (H1N1) for the first time since 1989. We conducted a case-control study to determine whether preceding influenza infection was directly associated with pneumococcal illness. We identified 13 children with severe pneumococcal pneumonia. Patients were more likely than control subjects to report experiencing an influenza-like illness in the 7-28 days preceding admission (matched odds ratio [OR], 12.4; 95% confidence interval [CI], 1.7-306). Likewise, family members of patients were more likely than those of control subjects to report experiencing an influenza-like illness in the 28 days preceding their admission date (OR, 2.6; 95% CI, 1.0-6. 3). Patients were more likely than control subjects to have a positive influenza A (H1N1) convalescent serology (matched OR, 3.7; 95% CI, 1.0-18.1). This study provides direct and indirect evidence that influenza infection led to severe pneumococcal pneumonia among these children. Prevention of pneumococcal disease should be included among the potential benefits of influenza vaccination.

Pulmonary embolization of a pacing electrode fragment complicating lead extraction.

We present a case that demonstrates an unusual complication of electrode extraction, namely asymptomatic embolization of a pacing electrode fragment into the pulmonary vascular bed.

Femoral complications and bed rest duration after coronary arteriography.

This randomized study using a pneumatic compression device found no significant difference in the femoral complication rate between 4 and 6 hours of bed rest after Judkin's coronary arteriography. The positive implications for the organization of an efficient service in busy tertiary centers include reduced patient discomfort, earlier ambulation and discharge, efficient staff deployment, and enhanced throughput.

Detection of a population of long-lived cells in mammary epithelium of the mouse.

The fate of dividing mouse mammary epithelial cells was followed by use of tritiated thymidine (3H-Tdr) autoradiography. Loss of label consistent with halving kinetics was observed at various times after injection; however, heavily labelled cells were frequently observed at two weeks and later, when none was expected. The grain count over these heavily labelled cells was often comparable with that 1 h after 3H-Tdr injection. Extensive serial sectioning revealed that the heavily labelled cells were often single cells surrounded by many unlabelled cells or that their label was in stark contrast (in excess of 20 reduced silver grains) to the surrounding group of cells whose label was just above background (a maximum of 3 grains). In addition, by injecting mice at different stages of oestrus, we demonstrated that these long-lived cells, although influenced by oestrus, replicated independently of the oestrogen peak. Our data support a model for mouse mammary epithelium that has a single 'stem' cell positioned within a group of its progeny to form a discrete proliferative unit. This model requires many such stem cells within the mammary epithelium and is consistent with similar models proposed for other tissues.

A simple and rapid method for the determination of thiocyanate in serum.

Studies were performed to evaluate ultrafiltration as a means for isolating thiocyanate from serum prior to its colorimetric determination as a ferric chloride complex. Recovery of thiocyanate from serum was enhanced by addition of alkali prior to preparation of the ultrafiltrate, and averaged 96.8%. The reproducibility (CV) of test was 2.3%, within-day; and 3.3%, between-day. The colorimetric reaction was linear to 100 micrograms/mL. The method was tested by determining thiocyanate concentrations in samples collected from smoking and nonsmoking individuals. Thiocyanate concentrations in patient samples, collected after IV-infusion of nitroprusside, were scattered around those of the general population, and ranged from 0.3 to 20 micrograms/mL.

Changes in calcium distribution during therapeutic plasmapheresis.

Observations of normal persons indicated that there was a net shift of serum calcium from the ionized and protein-bound fractions to the anion-bound fraction when these persons received citrate during donor plasmapheresis. To confirm these findings and to extend them to diseased persons, we measured total, ionized, and ultrafilterable Ca concentrations in 11 patients who were undergoing therapeutic plasmapheresis. Anticoagulation was achieved with anticoagulant citrate dextrose solution. Mean concentrations of total, ionized, and protein-bound Ca decreased, whereas the ultrafilterable and anion-bound fractions increased. Our results suggest that protein-bound Ca may be relatively labile and may help to maintain constant levels of ionized Ca. Also, the observed increase in the anion-bound Ca level with citrate infusion suggests a shift from the protein-bound and ionized Ca fractions to this pool.

Gentamicin/heparin interactions: effects on two immunoassays and on protein binding.

Heparin has been reported to have two different effects on gentamicin. One is the interference by heparin with the quantitation of gentamicin; the other is an increase in the bound fraction of gentamicin in the presence of serum. The reports conflict regarding what concentration of heparin causes these effects. The main objective of this study was to determine what effect heparin had on the determination of gentamicin using an enzyme immunoassay (EIA) or a fluorescence polarization immunoassay (FPIA). Heparin concentrations studied simulated the amounts that would be found in plasma when blood samples are collected with an evacuated heparinized tube (less than 30 U/ml), or the greater amounts that might be present when blood is collected from indwelling lines (100-200 U/ml). Heparin had no effect on the quantitation of gentamicin by FPIA. In measurements done by EIA, heparin had no effect at 28 U/ml but did significantly inhibit the reaction by 10-20% when its concentration was 100-200 U/ml. We studied the effects of heparin on the distribution equilibrium of gentamicin by measuring free gentamicin produced in an ultrafiltrate. It was found that the bound fraction increased as the heparin concentration increased. Our results with aqueous and serum-based samples suggest that the increased binding was the result of a direct binding of gentamicin to heparin, as well as a more complex interaction involving heparin, gentamicin, and proteins.

Quality control and therapeutic drug monitoring.

Dramatic improvements have been achieved in a relatively short time in the performance of therapeutic drug testing. The primary reasons for these advances have been the introduction of drug-specific immunoassays and, concomitantly, the availability of standards prepared in a biological matrix. For some drugs which are tested by other methods, such as the tricyclic antidepressants, interlaboratory variability is still excessively high. It is possible that this variability could be reduced through the proper preparation of serum-based standards. Manufacturers who provide quality control products could greatly assist the analyst by providing weighed-in target values for the drugs which have been added.

Rapid colorimetric assay for acetaminophen without salicylate or phenylephrine interference.

A simple rapid, and economical procedure is presented for the quantitative determination of acetaminophen in serum. Acetaminophen is extracted into solvent, and, when back-extracted into base, is simultaneously reacted with Folin-Ciocalteau reagent to form a colored complex. The potential interference of bilirubin is eliminated by treatment with p-diazobenzene sulfonic acid. Results obtained with this method agree with those obtained by "high-pressure" liquid chromatography.