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FORREST1 and other workers have shown that interesting data regarding bacterial metabolism can be obtained by microcalorimetry of growing cultures. In our investigations into the use of microcalorimetry as a means of differentiating one microbial species from another, we have obtained characteristic profiles for different members of the family Enterobacteriaceae by observing the heat produced during their growth in liquid media. The microcalorimeter (Instrumentation Laboratory, Inc.) used is of an experimental design operating at 37° C and having a response time of approximately 10 min. The long term baseline stability is 2% full scale or 0.8 µcal s−1 ml.−1 over a 14 h measuring period. The profiles are recorded on a conventional 10 inch strip chart recorder with a paper feed of 1 inch h−1. The inocula for the temperature equilibrated test vessel consisted of approximately 500 cells obtained by dilution of a logarithmically growing broth culture.

Summary In a double-blind controlled trial of male patients undergoing transurethral resection of the prostate, oral lorazepam was assessed against a placebo. The same anaesthetist performed all spinal blocks and made all assessments. The patients who received lorazepam had substantial amnesia for the operation and were drowsier, but remained cooperative during the procedure. Patient anxiety as assessed by the anaesthetist and as recalled by the patient was decreased, although anxiety assessment by linear analogue was the same for both groups. Lorazepam significantly increased the patient acceptability of spinal anaesthesia.

Eighty patients undergoing coronary artery surgery were randomly allocated to receive either 0, 2, 5, 10 or 15 jig/kg of fentanyl with induction of anaesthesia. Heart rate and blood pressure were measured before induction, after induction, and after intubation. The effects of fentanyl dose on both heart rate and mean arterial pressure (MAP) were evaluated in terms of both the mean and group responses. At all doses of fentanyl, mean heart rate increased after induction and rose further on intubation. The mean increase after induction was minimal at doses of 5 μg/kg and greater. The increase in heart rate after intubation was more difficult to block but with a fentanyl dose of 15 μg/kg, 87% of patients had heart rates below 100 bpm. As a group, the percentage of patients in whom the postintubation heart rate remained below 100 bpm increased progressively with the fentanyl dose. In contrast, mean MAP fell at all dose levels after induction, the mean fall being about 30 mmHg at 5 μg/kg and greater. Mean MAP exceeded pre-induction values after intubation with 0 and 2 μg/kg, and progressive attenuation of the MAP rise was found as the dose of fentanyl increased. The percentage of patients who did not exceed their preinduction MAP rose progressively with increasing dose of fentanyl with an ED50 of 3.7 μg/kg. If a minimal fall in mean MAP after induction with no rise above preinduction MAP is the sole criterion, a fentanyl dose of about 3 μg/kg is recommended. If heart rate is to be kept below 100 bpm, a dose of at least 10 μg/kg should be used. However, this dose or greater will cause the MAP to fall in some patients to less than 70 mmHg. The choice of the most appropriate dose depends on the anaesthetist's view of the relative importance of avoiding tachycardia or hypotension in the patient with coronary artery disease.

The ability of cricoid pressure to prevent inflation of the stomach during mask ventilation of a patient was studied. Fifty patients were randomly allocated to either have or not have cricoid pressure applied during a three-minute period of standardised mask ventilation. Patients who had had cricoid pressure applied had less gas in the stomach after mask ventilation (P< 0.001). However, in a subgroup of patients considered difficult to ventilate, cricoid pressure seemed less successful in preventing gastric inflation. Cricoid pressure is a useful technique for reducing gastric inflation during mask ventilation, particularly in patients who are relatively easy to ventilate.

Changes in mean arterial pressure (MAP) and plasma catecholamine concentrations in response to endotracheal intubation were examined in 8 patients who had received d-tubocurarine and 10 who had received suxamethonium. MAP fell after induction of anaesthesia and administration of the relaxant by a mean of 11 mmHg in those who had received suxamethonium and 19 mmHg in those who had received d-tubocurarine (p The results suggest that the fall in MAP after administration of d-tubocurarine does not attenuate the pressor response associated with intubation.

You have given publicity to various communications on the subject of the Albert or Gresham University; may we therefore request that you will extend a like favour to us, and insert a brief statement from one of the Colleges for Women, deeply interested in everything affecting higher education in and for London?

To the Editor:— It is to be hoped human drug trials, present and future, will be viewed with a more critical eye than has been the case in the past. I am writing regarding "A Controlled Double-Blind Study of Trimethobenzamide, Prochlorperazine and Pacebo" ( 196 :796, 1966), by Dr. Philip Bardfeld. The author found "no significant differences between saline and the trimethobenzamide," but made a strong statistical point about "the difference between the prochlorperazine and the placebo." I feel that any impression given by the author that prochlorperazine was almost significantly better than placebo should be corrected. The author's calculation of chi-square is in error, leading as it does to a P value between 0.07 and 0.08. This error arises from a failure to make a continuity correction which is necessary in 2 × 2 chi-square tables. Rather than the author's 3.25, the correct chi-square value is 2.37 which corresponds to