HALOTHANE ADSORPTION COMPLICATING THE USE OF SODA-LIME TO HUMIDIFY ANAESTHETIC GASES

If tbe anaesthetic circle system is arranged to increase thehumidity of fresh anaesthetic gases by placing the carbon dioxideabsorbent canister between the fresh gas inlet and the patient,drying of the soda-lime can occur. Very dry soda-lime adsorbssignificant quantities of halothane. Using fresh soda-lime,effluent halothane concentration reached 50% of the input concentrationin 35 s, but this time increased to 500s when dry soda-limewas used The use of dry soda-lime can result in a slow inhalationinduction or in the release of adsorbed halothane during a subsequentanaesthetic.     

Efficacy and Safety of Combination Therapy with Amiodarone and Type I Agents for Treatment of Inducible Ventricular Tachycardia

In a prospective study the efficacy of amiodarone in combinalion with the three Class I drugs mexiletine, fiecainide, orencainide was evaluated consecutively in 12 patients with recurrent venlriculav tachycardias (VT) by programmed stimulation. None of the tested drug combinations suppressed induction of sustained VT. The combination of amiodarone with Class IC drugs fJecainide and encainide prolonged the cycle length of VT significantly, whereas the combination with mexiletine did not hove the same degree of slowing on the VT cycle length. Several proarrhythmic effects occurred during the combination therapy with encainide: (1) frequent, spontaneous recurrences of hemodynamically well tolerated VT in four patients; (2) enhanced inducihilily of VT in three patients; (3) impaired termination of VT in three patients. Though a marked increase in QRS and QTc intervals was observed by combined treatment with encainide, no significant correlation could be established between aggravation of arrhythmia and plasma levels of encainide, degree of QRS widening, JT or QTc prolongation. The only predictor for the occurrence of proarrhythmic events was found in left ventricular ejection fraction. These findings suggest that in patients refractory to amiodarone alone or a combination with mexiletine, the combined treatment of amiodarone with other Class IC drugs prolongs the VT cycle length but does not suppress induction of VT during programmed stimulation. Combination therapy of amiodarone with encainide was associated with a high incidence of proarrhythmic effects.     

Alcohol and non-traffic unintended injuries

In a review of the English language literature on alcohol and unintentional injury we identified 21 studies on falls, 36 on drownings and 32 on bums from 1947-1986. The proportion of fatal and non-fatal fall victims who had been drinking ranged from 21–77%, and 18–53% respectively. In three more recent studies, 35–63% of persons fatally injured in falls had been drinking. In five other studies 13–37% of persons injured in non fatal falls had been drinking. In our earlier review of drowning studies with complete ascertainment and duration of submergence specified, 27–47% of those who drowned had positive BAC's. In eight subsequent studies, alcohol was identified in 21–47% of drowning deaths. In our earlier review alcohol was involved in 9-86% of bum deaths. In five more recent US studies, alcohol was found in 12–61 % of fatally injured burn victims. Case control studies are needed to establish whether alcohol increases the risk of trauma. Studies are also needed of interventions to reduce the proportion of these injuries where alcohol is involved.     

The Liver in Crohn's Disease

Clinical, haematological, biochemical, bacteriological, histological,and immuno-logical data of 100 patients with Crohn's diseasehave been examined with special reference to liver disease anddysfunction. Several significant points emerged from the clinical data. Therewas a high frequency of colonic involvement (57 per cent), andalso a very high proportion of patients (48 per cent) with systemiccomplications, the commonest systemic complications being iritis(19 per cent) and sacro-ileitis (15 per cent). Nearly three-quarters(71 per cent) of the patients had been operated on at some timeand 57 per cent had had one or more bowel resections. Localcomplications had occurred in 52 per cent of patients. Biochemical liver dysfunction was common, occurring in 26 (26per cent) patients, the BSP being the test most frequently abnormal.Two patients with established chronic liver disease had considerablebiochemical liver dysfunction, but about half the patients withlesser pathological changes in the liver had no biochemicalliver dysfunction. Of the 39 patients who underwent liver biopsy, 19 (19 per cent)had pathological changes in the liver, the commonest changesfound being pericholangitis (8 per cent), focal necrosis (6per cent), and fatty change (4 per cent). Only two patientshad chronic liver disease, one patient having chronic activehepatitis and the other portal cirrhosis associated with haemosiderosis. Culture of liver tissue for bacteria or L forms was uniformlynegative. Immuno-logical studies proved unrewarding in relationto liver disease and dysfunction in patients with Crohn's disease.However, two significant differences did emerge in comparingthe results of the immunological tests in ulcerative colitiswith those in Crohn's disease. Positive immunofluorescence teststo human colon were found in 12·7 per cent of patientswith ulcerative colitis, compared with only 2·3 per centof patients with Crohn's disease. There was also a significantdifference in IgM levels, with low values of IgM more frequentin Crohn's disease and high values more frequent in ulcerativecolitis; further research will be necessary to determine theunderlying reasons for this difference. The finding that the hepatic changes in Crohn's disease areremarkably similar to those in ulcerative colitis, both in frequencyand in type, leads to several possible explanations. First,ulcerative colitis and Crohn's disease may be different manifestationsof a single disease. Secondly, the liver disease and the otherremote complications, which are also similar in Crohn's diseaseand ulcerative colitis, may be a consequence of chronic inflammatorydisease of the intestine, irrespective of its exact nature.Thirdly, ulcerative colitis and Crohn's disease may both begeneralized diseases in which the brunt falls upon the intestinaltract. The aetiology of the hepatic lesions remains obscure but somedeductions can be drawn from the present data. From clinicalconsiderations, the overt liver disease appears to behave likea viral hepatitis which has become chronic. There is no evidenceto support the view that homologous serum hepatitis from bloodtransfusion is the significant factor. Drugs do not appear tobe of any great relevance. Immunological relationships are essentiallynegative. Portal bacteraemia appears to be an unlikely causeof the overt chronic liver disease encountered in the presentstudy.     

Use of Testosterone and Busulfan in the Treatment of Myelofibrosis with Myeloid Metaplasia

Clinical, hematologic, and isotope data from 10 patients with myelofibrosiswith myeloid metaplasia, before and after treatment with testosterone andbusulfan, are presented. Of the 10 patients treated with testosterone, fiveshowed a good response, three a slight response, and two, no response. Thebest therapeutic responses were seen in five women who either had a previoussplenectomy or in whom the spleen was not massively enlarged. Of the fivepatients treated with bulsufan only, one beneficial response was observed.The indications for and the consequences of the use of these drugs are discussed.

Submitted on May 14, 1963 Accepted on October 5, 1963     

Identifying the End of Ventricular Activation:

Late Potentials: Epicardial and Body Surface. Introduction: Identification of the end of the QRS is perhaps the single most important feature obtained from the high resolution signal-averaged electrocardiogram (SAECG). This point relies on computer algorithms to select a point ahove the noise levels. Prior studies to suhstantiate this approach using eleetrograms for comparison have demonstrated many examples of the hody surface recordings failing to detect the full extent of the late potentials.
Methods and Results: An animal model that generates late potentials was used in conjunction with epicardial cardiac mapping system to systematically examine the rea.sons for these failures. In I I of 13 dogs we found a concordance hetween the signal-averaged recordings and Ihe epicardial recordings within 5 msec. The two discordant studies were attrihuted to a failure of epicardial mapping to record all late potential sources. Also, a means of accurately comparing measurements from the two recording technologies was required in this study as well as a new definition for identifying the end of activation currents in epicardial eleetrograms.
Conclusion: To achieve these results required approaches different from those used in the clinical setting to record the SAECG. These include: (1) the analysis of individual XYZ leads as opposed to the vector magnitude derived from these leads; (2) visual identification of very low level signals, as automatic algorithms often fail to detect low level signals: and (3) the use of finite impulse response digital filters instead of the bidirectional Butterworth filter.     

Rupture of the oesophagus during cricoid pressure

Rupture of the oesophagus occurred during the application of cricoid pressure at induction of anaesthesia when the patient vomited. The patient, who was bleeding from a gastric ulcer, was found to have a lower oesophageal tear which, although repaired at operation, resulted in a fatal mediastinitis.     

Nephrotoxic and Ototoxic Effects of Hydroxygentamicin in Cats

Nephrotoxic and Ototoxic Effects of Hydroxygentamicin in Cats.Slighter, R. G, FABIAN, R. J., DONIKIAN, M. R., RENCH, R. D.,NEIDL, M. J., AND BOSHART, C. R. (1984). Fundam. Appl. Toxicoi.4, 568–576. Hydroxygentamicin, an aminoglycoside antibiotic,was administered subcutaneously to cats in doses up to 160 mgbase/kg daily for 10 to 13 weeks. Gentamtcin and a vehide solutionwere tested as positive and negative control, respectively;in one test netilmicin was also included for comparative purposes.Several parameters, including serum urea nitrogen, serum creatinine,organ/body weight ratios, serum and tissue concentrations ofthe antibiotics, and renal pathology, were determined to ascertainthe nephrotoxic potential of the three ami-noglycosides. Inaddition, observations for the onset of ataxia and impairmentof righting reflex were made during the course of the studiesto compare the vestibular ototoxic effects of the three antibiotics.Although serum urea nitrogen and serum creatinine values increasedmarkedly in those cats which eventually died or were sacrificedmoribund, these parameters in survivors were slightly but notsignificantly higher than controls. -Serum concentrations ofthe drugs were proportional to the doses administered, but renalconcentrations were approximately two and five times as highfor netilmicin and gentamicin, respectively, as they were forequivalent doses of hydroxygentamicin. The morphological changesobserved in the kidney of cats given 60 mg base/kg of hydroxygentamicinwere slightly less than those seen in cats administered 10 mgbase/ kg of gentamicin; similarly, kidney changes in cats givennetilmicin were observed approximately twice as frequently asthey were in those receiving equivalent doses of hydroxygentamicin.The nephrotoxic effects of aminoglycoside antibiotics were directlyrelated to renal drug concentration and not to serum concentration,which was a function of dose. The reason for the lower incidenceof vestibular ototoxic effects with hydroxygentamicin than withgentamicin was not as readily apparent. Vestibular damage resultingfrom netilmicin administration was restricted to ataxia; thelack of righting reflex impairment in all five cats was notcharacteristic of the pattern of vestibular ototoxicity associatedwitn aminoglycoside therapy.