OXYGEN AND AIR: Further Studies in Mice with Oxygen and Air as the Anaesthetic Vehicles with Halothane

A further study has been made to test the sensitivity of miceto halothane anaesthesia when the anaesthetic vehicle was 100per cent oxygen or air. This study showed that the mice anaesthetizedwith halothane in 100 per cent oxygen for 120 minutes toleratedsignificantly higher concentrations of halothane than thoseanaesthetized with halothane in air.     

PUPILLARY AND CIRCULATORY CHANGES AT THE TERMINATION OF RELAXANT ANAESTHESIA

Observations have been made of pupil size, as affected by intravenouslyadministered atropine and neostigmine, and by extubation, duringreversal of curarization. Pulse rate and blood pressure changeswere also recorded. Some degree of mydriasis was observed in70 per cent of patients after atropine, in 86 per cent afterneostigmine, and in 55 per cent at extubation. Pulse rate increasedin 88 per cent after atropine and decreased in 86 per cent afterneostigmine. Blood pressure rose in 70 per cent after atropineand in 58 per cent after neostigmine. Extubation caused no consistentpulse and blood pressure changes. It was considered that thepupillary changes noted would not be deleterious in intra-ocularsurgery     

MOBILIZATION OF PHILADELPHIA-NEGATIVE PERIPHERAL BLOOD MONONUCLEAR CELLS IN CHRONIC MYELOID LEUKAEMIA USING HYDROXYUREA AND G-CSF (FILGRASTIM)

A relatively simple and non-toxic out-patient-based regimen for the mobilization of Philadelphia-negative (Ph − ve) mononuclear cells in chronic myeloid leukaemia (CML) was evaluated in 10 patients, nine in stable chronic phase and one in accelerated phase. They received oral hydroxyurea at a mean dose of 3.5 g/m² daily for 7 d, followed by 300 μg of G-CSF daily until the last day of harvesting. In the nine chronic-phase patients the mean number of days from the end of hydroxyurea to the commencement of harvesting was 14.5 (range 10–18). The patient in accelerated phase recovered and was harvested after 6 d. The mean number of aphereses performed was 3.4. Adequate numbers of stem cells were obtained in 9/10 patients judged by our usual criteria. Side-effects were mild in comparison to published intravenous schedules. No patients lost their hair. Five (50%) patients required admission with neutropenic fever which responded to antibiotics in all cases. Four (40%) patients developed a transient rash and four (40%) experienced mild oral mucositis. This level of toxicity enabled half of the patients to be treated entirely on an out-patient basis. The harvest products were analysed for cells belonging to the leukaemic clone by conventional cytogenetics, FISH and PCR. All were PCR positive. The mean Ph positivities by cytogenetics and FISH were comparable at 18.1% and 15% respectively. Half the patients had >% normal metaphases. We conclude that this approach is comparable in efficacy to published intravenous regimens and significantly less toxic. It can be safely used at diagnosis before interferon therapy commences.     

THE EFFECTS OF VARIOUS OXYGEN CONCENTRATIONS IN THE ANAESTHETIC VEHICLE ON INDUCTION TIMES AND SURVIVAL TIMES WITH HALOTHANE ANAESTHESIA

Studies were made to test the effects in mice exposed to halothaneof various percentages of oxygen in the anaesthetic vehiclewere on induction and survival times. Over all, increaing oxygenconcentrations in the vechicle were associated with longer inductiontimes with 4 per cent and 10 per cent halothane and with longersurvival times with 10 per cent halothane. It is not possiblefrom the results to define accurately the respective roles whichhaemoglobin, oxygen saturation, and the carriage of oxygen insolution in the plasma, play in prolonging induction and survivaltimes.     

OXYGEN AND ANAEMIA: THEIR EFFECTS IN MICE, ON INDUCTION TIME AND SURVIVAL TIME WITH HALOTHANE ANAESTHESIA

This paper reports the results of five studies on female miceto investigate the effects of halothane anaesthesia in air and100 per cent oxygen on induction time, survival time and sensitivityto halothane, in bled and unbled mice. Studies on the effectof anaemia on induction time and survival time showed that reductionsof haemoglobin content significantly reduced induction timesin mice anaesthetized with 10 per cent halothane in air and100 per cent oxygen (2 1./min), but did not significandy affectthe survival times in the same groups of mice. The use of 100per cent oxygen instead of air as the anaesthetic vehicle causeda highly significant increase in induction times and survivaltimes in both bled and unbled mice. Toxicity studies to determinethe halothane concentrations required to kill 50 per cent and99 per cent of mice in 30 minutes were used to confirm the resultsof the above survival studies. One study showed that in unbledmice, the mice were significantly more sensitive to halothane/airanaesthesia than to halothane/100 per cent oxygen anaesthesia.Other studies showed that a mean haemoglobin reduction of 31per cent did not significandy affect the mouse sensitivity tohalothane/100 per cent oxygen anaesthesia, but a reduction of45 per cent significantly increased the sensitivity of the bledmice to halothane/100 per cent oxygen. Body weight was shownto have a highly significant effect on induction time and survivaltime with 10 per cent halothane/100 per cent oxygen, but a non-significanteffect with 10 per cent halothane/air.     

CT/1341: A Steroid Anæsthetic Induction Agent

A study has been made on 100 patients of the steroid anæsthetic agent CT/1341. This drug is shown to be a satisfactory induction agent, which is relatively trouble-free and has good patient acceptance.