Continuous monitoring of depth of sedation by EEG spectral analysis in patients requiring mechanical ventilation

Twenty-three patients undergoing intensive therapy had continuousEEG recording in an attempt to assess depth of sedation usingspectral analysis. Median power frequency (MPF) and spectraledge frequency (SEF) were calculated and correlated with theclinical sedation score and blood concentration of sedativedrug. Fifteen patients received isoflurane and eight midazolam.There was no correlation between MPF or SEF and sedation scoreor blood concentration of drug. These results suggest that nosimple measure of the EEG is likely to correlate with depthof sedation in critically ill patients.     

Chrome congestive heart failure: Radiofrequency ablation of accessory pathways: implications of accumulated experience and time dedicated to procedures

Previous reports on radiofrequency ablation of accessory pathwayshave shown that the experience of the operator is of crucialimportance in reducing fluoroscopy time and achieving highersuccess rates. However, a detailed analysis of this importantissue has not been previously attempted We analysed 71 consecutive ablation procedures undertaken atSt George's Hospital by the same electrophysiology group andalways with the same first operator. Of all procedures, 66 (916%)were successful, as judged by abolition of accessory pathwayconduction without recurrence within the next 24 h. Failuresincluded two out of 38 left-sided pathway procedures (5·3%),one out of 11 intermediate septal (9·1%) and four outof 22 right-sided pathway procedures (18·2%). These differencewere not statistically significant. Average procedure and screeningtimes for all procedures were 162·9±86·0min and 56·8±48·2 mm respectively, whereasthe median of the number of discharges was 12, ranging fromone to 51. There was no significant difference between pathwaygroups or between concealed and non-concealed pathways in respectto procedure and screening time or number of discharges. Therewas a significant tendency towards decreased procedure and screeningtimes with accwnulating experience and this was similar forall pathway groups. There was also a tendency towards improvedcwnulative success rates with time dedicated to procedures. We conclude that a certain amount of ablation experience isrequired, even by experienced electrophysiologists, before arelatively high success rate without long radiation exposurecan be achieved, regardless of the location or the mode of conductionof the pathway. Success rates increase with procedure time,suggesting that early abandonment of the procedure may resultin higher failure rates in diffcult cases.     

Use of the rocking bed in the treatment of neurogenic respiratory insufficiency

We describe 53 patients who received ventilatory support witha rocking bed. Diagnoses included previous poliomyelitis (30),muscular dystrophy (12), motor neurone disease (4), adult-onsetacid maltose deficiency (4) and a miscellaneous group (3). Patientspresented with respiratory insufficiency characterized by diaphragmweakness, progressive nocturnal hypoventilation and/or acuteor chronic respiratory failure. Domiciliary rocking beds wereused by 43 patients for a mean of 16.0 years (range 1 monthto 35 years). Most patients were able to breathe adequatelyby day when sitting or standing, but needed assistance by rockingbed for 6–11 h when lying down for sleep. The rockingbed was well-tolerated, and associated with both symptomaticrelief and amelioration of arterial blood gas abnormalities.Seventeen of these 43 patients discontinued its use, eitherbecause of discomfort (9) or increasing respiratory insufficiency(8). The rocking bed is a valuable adjunct in the managementof the respiratory insufficiency associated with neuro-musculardisease.     

Effect of low glycogen on glycogen synthase in human muscle during and after exercise

Subjects cycled at a work load calculated to elicit 75% of maximal oxygen uptake on two occasions: the first to fatigue (34.5 ± 5.3 min; mean ± SE), and the second at the same workload and for the same duration as the first. Biopsies were obtained from the quadriceps femoris muscle before and immediately after exercise, and 5 min post-exercise. Before the first experiment, muscle glycogen was lowered by a combination of exercise and diet, and before the second, experiment muscle glycogen was elevated. In the low glycogen condition (LG), muscle glycogen decreased from 169 ± 15 mmol glucosyl units kg^-1dry wt at to rest to 13 ± 6 after exercise. In the high glycogen condition (HG) glycogen decreased from 706 ± 52 at rest to 405 ± 68 after exercise. Glycogen synthase fractional activity (GSF) was always higher during the LG treatment. During exercise in the HG condition, those subjects who cycled for < 35 min (n= 3) had GSF values in muscle which were lower than at rest, whereas those subjects who cycled for > 35 min (n= 4) had values which were similar to or higher than at rest. Thus the change in GSF in muscle during HG was positively related to the exercise duration (r= 0.94; y = 254–17x + 0.3x²; P < 0.001) and negatively related to the glycogen content at the end of exercise (r=–0.82; y= 516–2x + 0.001x²; P < 0.05). During LG exercise GSF remained constant. GSF increased markedly after 5 min post-exercise in both HG and LG conditions. cAMP dependent protein kinase activity increased similarly during both LG and HG exercise and reverted to the preexercise values 5 min post-exercise. It is concluded that muscle contraction decreases GSF, but low glycogen levels can attenuate or abolish the decrease in GSF. The rapid increase of GSF during recovery from exercise does not require glycogen depletion during the exercise.     

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.