Anaesthesia, 1975, Volume 30, pages 685-692
Correspondence* The Editor would be grateful ifcorrespondentswould double-space their copy and use the format in which letters are customarily printed in Anaesthesia. Deaths due to local analgesia in dentistry
685
J. Antonio Aldrete, MD, M S & Ramesh Narang, D S c Blood transfusion A. F. M. Little, MB, FFARCS & R. E. Loder, MA, MB, FFARCS, The Editor
686
Limitations of electrocardioscopy Mordechai Manoach, PhD, & Sidney Gassner, M D P.J. M. Brock, MB, FFARCS, DRCOG & J. B. Bowes, MB, FFARCS
688
Continuous, positive airway pressure (CPAP) M. Heifetz, M D & Fabio Zueibil, M D
689
Metoclopramide and oral premedication E. N. S. Fry, MB, FFARCS, DA
690
Adverse reactions to intravenous anaesthetics J. Watkins, PhD, BSc, J. A. Thornton, MD, FFARCS & R. S. J. Clarke MD, PhD, FFARCS
69 1
Confirming the position of an endotracheal tube J. C. Stoddart, MD, FFARCS
69 1
Flunitrazepam in dental outpatients W. N. Rollason, MB, FFARCS
692
A simple method of recording the ventilator history of a patient Alan Gilston, MB, FFARCS
692
Deaths due to Local Analgesia in Dentistry We have read with great interest Dr P. J. Tomlin’s paper on ‘Death in outpatient dental practice’ and the correspondence which it provoked (Anaesthesia, 1974,29,551 and 30,96 & 239). Dr Tomlin suggested that the deaths of cases S1 and S3 (which followed local analgesia alone) might have been due to coronary insufficiency, ventricular failure or acute sensitivity to lignocaine. We would like to offer an alternative explanation for these two catastrophes. We agree with Dr Bromage (Anaesthesia,30, 239) that allergic reactions to lignocaine are extremely rare. We have studied more than 90 patients alleged to be allergic to lignocaine and have encountered only 2 possible cases both of which are dubious since their symptoms
* Correspondence should be addressed to the Editor of Anaesthesia, Association of Anaesthetists of Great Britain & Ireland, Tavistock House South, Tavistock Square, London, WClH 9JP, England. The section is compiled by Dr Richard H. Ellis, Consultant Anaesthetist, St Bartholomew’s Hospital, London. 685
686
Correspondence
(itching and erythema at the site of injection) do not necessarily represent antigen-antibody reactions.’ Convulsions resulting from anoxia may have led to the deaths but there was no apparent reason for a healthy patient to suddenly suffer coronary insufficiency and ventricular failure. Dr Bromage’s hypothesis of subperineural spread is feasible but would probably result in complete anaesthesia or total spinal anaesthesia which eventually causes respiratory paralysis and hypoxia. This topic has been of interest to us in our attempts to explain the adverse reactions which follow the injection of very small volumes of local anaesthetic agents into the head and neck. We have conducted a series of observations on the basis of which we would like to propose an alternative explanation for the deaths of Cases S1 and S3 in Dr Tomlin’s series. This is the reversal of carotid blood flow caused by the injection of very small volumes (usually 1.8 rnl) of 2% lignocaine into a branch of the external carotid artery. The injection is made under high pressure with a dental syringe and a reverse flow phenomenon occurs as a result of which the local anaesthetic may enter the internal carotid artery. Thus even small volumes of local anaesthetic agents may produce toxic reactions, including convulsions and apnoea, which are similar to those seen when larger volumes are injected into interstitial tissues or blood vessels. In our study using rhesus monkeys the centripetal injection of 3 ml of contrast medium into the mandibular artery resulted in an easily visible cerebral arteriogramZwhich suggests that reverse carotid flow may well occur in the circumstances described above. Since aspiration of blood may occur in 3-4% of all dental injection3 we propose the inadvertent intraarterial injection of lignocaine as a possible cause of death in the 2 patients. The incidence of intravascular injections is unknown since negative aspiration tests for blood do not necessarily eliminate the hazard of intravascular (commonly intra-arterial) i n j e ~ t i o n . ~ We feel that great caution should be exercised during local anaesthetic injections in the head and neck. Careful aspiration tests should be made before the injection begins and after each 0.5 ml is injected and the needle should probably be moved slightly during the p r o c e d ~ r e . ~ We certainly agree with D r Tomlin’s statement that further investigations are needed to determine the frequency of and circumstances in which intravascular injections of local anaesthetics occur in dentistry. The redesigning of needle tips may prevent this complication. Departments of Anesthesiology and Oral Surgery, University of Louisville Schools of Medicine and Dentistry, Louisville, Kentucky 40202, U.S.A.
J. ANTONIO ALDRETE RAMESH NARANG
References 1. ALDRETE, J.A. & O’HIGGINS, J.W. (1971) Evaluation of patients with history of allergy to local anaesthetic drugs. Southern Medical Journal, 64, 11%. 2. ALDRETE, J.A., NARANG, R., LIEM,S., SADA,T. & MILLER, G.P. (1975) Untoward reaction to local anaesthetics via reverse intracarotid flow. Journal of Dental Research, 54, 145. 3. BARTLETT, F.Z. (1972) Clinical observations on the effects of injection of local anesthetics preceded by aspiration. Oral Surgery, oral medicine and oral pathology, 33, 520. 4. MOORE,D.C. (1955) Complications of Regional Anesthesia, 1st edn, p. 14. Charles C. Thomas,
Illinois.
Blood Transfusion The need for blood in major trauma Your editorial on blood transfusion (Anaesthesia, 1975, 30, 149) may unintentionally do a great disservice to patients involved in major accidents. You rightly call for thought before blood transfusion is given during elective operations but I think you should have emphasised
Correspondence* The Editor would be grateful ifcorrespondentswould double-space their copy and use the format in which letters are customarily printed in Anaesthesia. Deaths due to local analgesia in dentistry
685
J. Antonio Aldrete, MD, M S & Ramesh Narang, D S c Blood transfusion A. F. M. Little, MB, FFARCS & R. E. Loder, MA, MB, FFARCS, The Editor
686
Limitations of electrocardioscopy Mordechai Manoach, PhD, & Sidney Gassner, M D P.J. M. Brock, MB, FFARCS, DRCOG & J. B. Bowes, MB, FFARCS
688
Continuous, positive airway pressure (CPAP) M. Heifetz, M D & Fabio Zueibil, M D
689
Metoclopramide and oral premedication E. N. S. Fry, MB, FFARCS, DA
690
Adverse reactions to intravenous anaesthetics J. Watkins, PhD, BSc, J. A. Thornton, MD, FFARCS & R. S. J. Clarke MD, PhD, FFARCS
69 1
Confirming the position of an endotracheal tube J. C. Stoddart, MD, FFARCS
69 1
Flunitrazepam in dental outpatients W. N. Rollason, MB, FFARCS
692
A simple method of recording the ventilator history of a patient Alan Gilston, MB, FFARCS
692
Deaths due to Local Analgesia in Dentistry We have read with great interest Dr P. J. Tomlin’s paper on ‘Death in outpatient dental practice’ and the correspondence which it provoked (Anaesthesia, 1974,29,551 and 30,96 & 239). Dr Tomlin suggested that the deaths of cases S1 and S3 (which followed local analgesia alone) might have been due to coronary insufficiency, ventricular failure or acute sensitivity to lignocaine. We would like to offer an alternative explanation for these two catastrophes. We agree with Dr Bromage (Anaesthesia,30, 239) that allergic reactions to lignocaine are extremely rare. We have studied more than 90 patients alleged to be allergic to lignocaine and have encountered only 2 possible cases both of which are dubious since their symptoms
* Correspondence should be addressed to the Editor of Anaesthesia, Association of Anaesthetists of Great Britain & Ireland, Tavistock House South, Tavistock Square, London, WClH 9JP, England. The section is compiled by Dr Richard H. Ellis, Consultant Anaesthetist, St Bartholomew’s Hospital, London. 685
686
Correspondence
(itching and erythema at the site of injection) do not necessarily represent antigen-antibody reactions.’ Convulsions resulting from anoxia may have led to the deaths but there was no apparent reason for a healthy patient to suddenly suffer coronary insufficiency and ventricular failure. Dr Bromage’s hypothesis of subperineural spread is feasible but would probably result in complete anaesthesia or total spinal anaesthesia which eventually causes respiratory paralysis and hypoxia. This topic has been of interest to us in our attempts to explain the adverse reactions which follow the injection of very small volumes of local anaesthetic agents into the head and neck. We have conducted a series of observations on the basis of which we would like to propose an alternative explanation for the deaths of Cases S1 and S3 in Dr Tomlin’s series. This is the reversal of carotid blood flow caused by the injection of very small volumes (usually 1.8 rnl) of 2% lignocaine into a branch of the external carotid artery. The injection is made under high pressure with a dental syringe and a reverse flow phenomenon occurs as a result of which the local anaesthetic may enter the internal carotid artery. Thus even small volumes of local anaesthetic agents may produce toxic reactions, including convulsions and apnoea, which are similar to those seen when larger volumes are injected into interstitial tissues or blood vessels. In our study using rhesus monkeys the centripetal injection of 3 ml of contrast medium into the mandibular artery resulted in an easily visible cerebral arteriogramZwhich suggests that reverse carotid flow may well occur in the circumstances described above. Since aspiration of blood may occur in 3-4% of all dental injection3 we propose the inadvertent intraarterial injection of lignocaine as a possible cause of death in the 2 patients. The incidence of intravascular injections is unknown since negative aspiration tests for blood do not necessarily eliminate the hazard of intravascular (commonly intra-arterial) i n j e ~ t i o n . ~ We feel that great caution should be exercised during local anaesthetic injections in the head and neck. Careful aspiration tests should be made before the injection begins and after each 0.5 ml is injected and the needle should probably be moved slightly during the p r o c e d ~ r e . ~ We certainly agree with D r Tomlin’s statement that further investigations are needed to determine the frequency of and circumstances in which intravascular injections of local anaesthetics occur in dentistry. The redesigning of needle tips may prevent this complication. Departments of Anesthesiology and Oral Surgery, University of Louisville Schools of Medicine and Dentistry, Louisville, Kentucky 40202, U.S.A.
J. ANTONIO ALDRETE RAMESH NARANG
References 1. ALDRETE, J.A. & O’HIGGINS, J.W. (1971) Evaluation of patients with history of allergy to local anaesthetic drugs. Southern Medical Journal, 64, 11%. 2. ALDRETE, J.A., NARANG, R., LIEM,S., SADA,T. & MILLER, G.P. (1975) Untoward reaction to local anaesthetics via reverse intracarotid flow. Journal of Dental Research, 54, 145. 3. BARTLETT, F.Z. (1972) Clinical observations on the effects of injection of local anesthetics preceded by aspiration. Oral Surgery, oral medicine and oral pathology, 33, 520. 4. MOORE,D.C. (1955) Complications of Regional Anesthesia, 1st edn, p. 14. Charles C. Thomas,
Illinois.
Blood Transfusion The need for blood in major trauma Your editorial on blood transfusion (Anaesthesia, 1975, 30, 149) may unintentionally do a great disservice to patients involved in major accidents. You rightly call for thought before blood transfusion is given during elective operations but I think you should have emphasised
