EFFECTS OF DIAZEPAM AND MIDAZOLAM ON RECOVERY FROM ANAESTHESIA IN OUTPATIENTS

Sixty patients were randomly allocated in an open study to receiveeither midazolam or diazepam (Diazemuis) with fentanyl and etomidatefor induction and maintenance of anaesthesia during day-staygynaecological surgery. The excitatory effects of etomidatewere controlled by the benzodiazepine-fentanyl combination inboth groups. No significant difference in the quality of recovery(as judged by Trieger test analysis), amnesia, incidence ofrecall of pain on injection of etomidate or nausea and vomitingcould be demonstrated between the groups. There was a high degree(97%) of patient acceptance.     

USE OF AN EMULSION OF ICI 35868 (PROPOFOL) FOR THE INDUCTION AND MAINTENANCE OF ANAESTHESIA

2,6-Diisopropyl phenol in a fat emulsion formulation (propofol)has been used to supplement 67% nitrous oxide in oxygen anaesthesiain 20 patients premedicated with morphine 0.15 mg kg^-1and atropine0.6 mg, and undergoing body surface surgery. Following an inductiondose of propofol 2.5 mg kg^-1, the mean maintenance dose was73.4µg kg^-1min^-1. When compared with 10 patients receivingAlthesin to supplement nitrous oxide in oxygen in a similarmanner, recovery was considerably faster following propofol.The only major side-effect associated with the use of propofolwas pain on injection in nine out of 20 patients. When the patientsreceiving propofol were compared with a second control group(n = 11) in whom anaesthesia was induced with thiopentone 4mg kg^-1and maintained with 1 % halothane and nitrous oxide inoxygen, the former group showed a significant (P<0.01) decreasein the plasma cortisol concentration 30 min after the inductionof anaesthesia. However, by 3 h after induction, the cortisolconcentration in both groups was not significantly differentfrom the baseline (pre-induction) value. The mechanism of thisdecrease is not known. In vestigation of the influence of thefat emulsion on blood coagulation andfibrinolysis revealed nodifferences when compared with patients receiving Althesin.     

Effect of disodium cromoglycate on activation of human eosinophils and neutrophils following reversed (anti-IgE) anaphylaxis

Immunological release of histamine and lipid mediators is known to occur when basophils, contained in whole blood human leucocytes, are incubated with anti-IgE (reversed anaphylaxis). In the present study we show that IgE-dependent stimulation of basophils was associated with activation of bystander eosinophils and neutrophils, as assessed by enhanced complement (C3b) and IgG (Fc) rosettes, and increased cytotoxicity for complement-coated schistosomula of Schistosoma mansoni. These changes in eosinophil and neutrophil function were totally inhibited in a dose-dependent fashion by prior incubation with disodium cromoglycate (DSCG). In all in vitro systems examined, complete inhibition of enhancement was observed with concentrations as low as 10^-7 moles/1. In contrast, DSCG had no effect on histamine release, or the percentage of rosettes or cytotoxicity prior to anti-IgE stimulation. These results suggest that DSCG inhibits activation of inflammatory cells consequent to an IgE-dependent stimulus.     

Bone marrow and serum connective tissue polypeptides in idiopathic myelofibrosis

Summary The distribution of collagen type VI and tenascin has been determined in both normal and myelofibrotic bone marrow by immunohistological techniques. In normal sections positivity was demonstrated in the periosteum (collagen type VI and tenascin) and in the walls of small blood vessels (tenascin). In contrast, myelofibrotic bone marrow showed an increased deposition of both proteins, especially collagen type VI, although this increase was restricted to the later fibrotic stages of the disease. Serum concentrations of collagen type I (PICP), collagen type III (PIIIP) and laminin (laminin PI) related polypeptides were determined in a further 26 patients. PIIIP levels were significantly raised, in contrast to PICP and laminin PI concentrations. All three markers, however, were significantly elevated in patients with active/transforming disease. Laminin PI and PICP levels showed a strong correlation, indicating a relationship between basement membrane and interstitial collagen metabolism, although they do not appear to offer any advantage over PIIIP for the monitoring of disease activity.     

EUROPEAN LEAGUE AGAINST RHEUMATISM STUDY OF ADVERSE REACTIONS TO D-PENICILLAMINE

An international multicentre study of adverse reactions to D-penicillaminewas undertaken on 2879 patients exposed to the drug—1491of them a prospective sample. The majority of patients werebeing treated for rheumatoid arthritis. Over a period of 18months, 319 (21%) of patients in the prospective sample developedadverse reactions necessitating drug withdrawal; two thirdsof these occurred during the first 3 months of treatment. Themost frequently-occurring adverse reactions involved skin (6%),kidneys (4%), gastro-intestinal tract (4%) and haemopoiesis(3%). Adverse effects, considered to be serious by the reportingphysician, included fever and leucopenia during the early weeksof treatment and, after some months of drug exposure, proteinuria,myasthenia gravis, dyspnoea and pemphigus. Two patients died,one of fulminating septicaemia and the other was found at autopsyto have had multiple lung abscesses following unexplained anaemiaand hemiparesis. KEY WORDS: D-Penicillamine, Rheumatoid arthritis, Adverse drug reaction     

PR/RR Interval Ratio During Rapid Atrial Pacing:

Method for Confirming Slow Pathway Conduction. Introduction: Although the AV conduction curve in patients with AV nodal reentrant tachycardia (AVNRT) is usually discontinuous, many patients with this arrhythmia do not demonstrate criteria for dual AV nodal pathways. During rapid atrial pacing, the PR interval often exceeds the pacing cycle length when there is anterograde conduction over the slow pathway and AVNRT is induced. The purpose of this prospective study was to determine the diagnostic value of the ratio of the PR interval to the RR interval during rapid atrial pacing as an indicator of anterograde slow pathway conduction in patients undergoing electrophysioiogic testing. Methods and Results: The PR and RR intervals were measured during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction in four study groups: (1) patients with inducible AV nodal reentry and the classical criterion for dual AV nodal pathways during atrial extrastimulus testing (AVNRT Group 1); (2) patients with inducible AV nodal reentry without dual AV nodal pathways (AVNRT Group 2); (3) control subjects ≤ 60 years of age without inducible AV nodal reentry; and (4) control subjects > 60 years of age without inducible AV nodal reentry. For both groups of patients with inducible AV nodal reentry, AV conduction was assessed before and after radiofrequency ablation of the slow AV nodal pathway. Before slow pathway ablation, the PR/RR ratio exceeded 1.0 in 12 of 13 AVNRT Group 1 patients (mean 1.27 ± 0.21) and 16 of 17 AVNRT Group 2 patients (mean 1.18 ± 0.15, P = NS Group 1 vs Group 2). After slow pathway ablation, the maximum PR/RR ratio was < 1.0 in all AVNRT patients (Group 1 = 0.59 ± 0.08, P < 0. 00001 vs before ablation: Group 2 = 0.67 ± 0.11; P < 0.00001 vs before ablation). Among both groups of control subjects, the PR/RR ratio was > 1.0 in only 3 of 27 patients with no relation to patient age. Conclusion: The ratio of the PR interval to the RR interval during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction provides a simple and clinically useful method for determining the presence of slow AV nodal pathway conduction. This finding may be particularly useful in patients with inducible AV nodal reentry without dual AV nodal physiology on atrial extrastimulus testing.     

The Effects of Ventricular Fibrillation Duration and a Preceding Unsuccessful Shock on the Probability of Defibrillation Success Using Biphasic Waveforms in Pigs

Influence of VF Duration on Defibrillation Efficacy. introduction: While the defibrillation threshold has been reported to increase with ventricular fibrillation (VF) duration for monophasic waveforms, the effect of VF duration for biphasic waveforms is unknown. Methods and Results: The ED 50 requirements (the 50% probability of defibrillation success) for an endocardial lead system, which included a subcutaneous array, were determined by logistic regression using a recursive up-down algorithm for a biphasic waveform ((6/6 msec). The study was performed in two parts, each with eight pigs. In part 1, ED 50 was compared for shocks delivered after 10 seconds of VF and for shocks delivered after 20 seconds of VF following a failed first shock at 10 seconds. Energy at ED 50 decreased from 6.5 ± 0.9, J for shocks delivered after 10 seconds of VF to 4.9 ± 0.8, J (P < 0.01) for shocks delivered after 20 seconds. To determine if improved second shock efficacy was a result of preconditioning by the failed first shock or a function of VF duration, part 2 of the study compared defibrillation efficacy between shocks delivered after 10 seconds of VF with shocks delivered after 20 seconds of VF with and without a failed first shock at 10 seconds. Mean energy at ED 50 decreased from 10.1 ± 2.4, J for shocks delivered after 10 seconds of VF to 7.9 ± 2.4 J (P < 0.01) and 7.5 ± 3.2 J (P < 0.01) for shocks delivered after 20 seconds of VF with and without a failed first shock, respectively. The mean energy at KD 50 for shocks delivered after 20 seconds of VK with and without a failed first shock was not significantly different (P = 0.53). A strong linear correlation for energy at ED 50 was found between shocks delivered after 10 seconds of VF and shocks delivered after 20 seconds of VF following a failed first shock (r = 0.95, P < 0.01). Conclusion: (1) As opposed to monophasic shocks, ED 50 is significantly lower for biphasic shocks delivered after 20 seconds of VF compared with shocks delivered after 10 seconds of VF in pigs. (2) An unsuccessful biphasic shock in pigs does not affect the defibrillation efficacy for a subsequent shock. (3) ED 50 for a biphasic shock delivered after 20 seconds of VK is linearly related to ED 50 for a shock delivered after 10 seconds of VK.