354

Correspondence

early mobilisation, alimentation and ambulation even after operations on the chest, loin or upper abdomen. Royal Berkshire Hospital, Reading RGI 5AN

J. MACKENZIE

References [I] EASONMJ, WYATT R. Paravertebral thoracic block--a reappraisal. Anaesthesia 1979; 34: 63842. 12) CONACHER ID. Resin injection of thoracic paravertebral spaces. British Journal of Anaesthesia 1988; 61: 657-6 I .

Pattern of use of the laryngeal mask airway We recently conducted a survey of the use of the laryngeal mask airway (LMA) by 66 anaesthetists within the Cardiff teaching hospitals. Only one anaesthetist considered that the LMA had no role to play in their anaesthetic practice. The LMA was more popular with the senior registrars and registrars than with the consultants; it was also noted that the consultants more readily abandoned insertion of the LMA (8% as apposed to the registrars’ 3%). The contraindications to usage of the LMA increased in accordance with the seniority of the anaesthetist. The consultants, as a group, listed eight contradindications: a prone or head-down position, IPPV, risk of regurgitation, risk of bleeding, the use of muscle relaxants, short cases (less than 5 min in duration) and lastly those cases where high airway pressures occur. The preferred induction technique for insertion of the LMA varied considerably between grades; for example 36% of the consultants and 50% of registrars used propofol alone, whereas no senior registrar used solely propofol. An induction technique, involving a combination of fentanyl and propofol, was used by 65% of senior registrars, compared to respective figures of 32% of the consultants and 43% of the junior registrars. There was general agreement between grades about the role of the LMA in conjunction with IPPV. Equal figures

(64%) of both consultants and senior registrars would not use an LMA for prolonged IPPV. Only 27% of the consultants considered there should be a maximum time limit beyond which they would not use an LMA, compared to 55% and 50% for the senior registrars and registrars. The reported frequency of complications was not influenced by grade of operator; the most common complication was respiratory obstruction, occurring in approximately 6% of cases involving the LMA. It was noted that almost all anaesthetists removed the LMA in the operating theatre at the end of the surgical procedure rather than in the recovery room as advocated by Brain in the Intavent instruction manual [I]. The LMA has rapidly established itself in anaesthetic practice as highlighted by this survey, but it is interesting to note the differences in patterns of its use by different grades of anaesthetists. University Hospital of Wales Cardiff CF4 4XW

J.A. HUGHES P.S. GATAURE

Reference [I] BRAIN AIJ. The lntavent laryngeal mask instruction manual.

Berkshire: Lucas Graphics, 1991.

The laryngeal mask airway in recovery We were interested to read Dr Davies’ letter, ‘A false compatibility’ (Anaesthesia 1991; 46: 991), especially in the context of the editorial in the same issue on supplementary oxygen [I]. We are sure that many anaesthetists share our view, that it was only a matter of time before a misconnection such as this was reported. Sadly, despite the availability of suitable T-piece systems for the delivery of supplementary oxygen to the laryngeal mask airway [2], this problem of connection to the high pressure oxygen supply is bound to recur. Brain has stated recently that ‘Adequate anaesthesia during surgery and avoidance of disturbing the patient during recovery are certainly fundamental to smooth, uneventful use of the laryngeal mask’ [3]. We suggest that misconnection and the problems associated with disturbance of the patient emerging from anaesthesia with the laryngeal mask in position could be completely avoided by removal of the laryngeal mask in the operating theatre by the anaesthetist whilst the patient is still anaesthetised. We consider this to be the safest

approach and feel that delegation of the responsibility for care and removal of the laryngeal mask airway to anyone other than an anaesthetist should only be contemplated after careful consideration of the risks and benefits. We have yet to find a good indication in the routine case for leaving the laryngeal mask airway in place during recovery. University Department of Anaesthesia. Leicester Royal Injrmary, Leicester LEI 5 W W .

R.J. ERSKINE P.G. RABEY

References [ I ] NEWTONN1. Supplementary oxygen-potential for disaster. Anaesthesia 1991; 46: 905-6. APL. Postoperative oxygen via the laryngeal mask [2] GWDWIN airway. Anaesthesia 1991; 46: 700. [3] BRAIN AIJ. The laryngeal mask and the oesophagus. Anaesthesia I99 I: 46: 701-2.

Defective feed mount I would like to report a potentially serious hazard when using a feed mount attached to the common gas outlet of an anaesthetic machine. Figure 1 shows this set-up as used in our department to supply a variety of ventilators. On

transferring the second patient of a cardiac operating list into the operating theatre, ventilation was controlled artificially using a Servo 900D ventilator which had been used without problems on the first patient of the day.

Pattern of use of the laryngeal mask airway.

354 Correspondence early mobilisation, alimentation and ambulation even after operations on the chest, loin or upper abdomen. Royal Berkshire Hospit...
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