Cardiac Pacemakers-Lichter et al. MEDICALJUTN-experience provides the substance for Jessen and Rosen's caution.We are grateful to Professor Nimmo, of the Department of Physics, University of Otago, and to his staff for their valuable contribution to this study. We wish to thank Mr. Colin Booth and Miss Pamela Fraser, of the Department of Surgery, University of Otago, for technical help, and Miss Nancy Bowles for secretarial assistance. REFERENCES Borrie, J., and Lichter, I. (1964). N. Z. med. 7., 63, 31. Burchell, H. B. (1961). Circulation, 24, 161. Jessen, C., and Rosen, J. (1963 J7., 1965, 1, 1518-1523 Intermittent positive-pressure respiration (I.P.P.R.) is now recognized as having an important part to play in the treatment of chest injuries (Barrett, 1960 ; Griffiths, 1960 ;Windsor and Dwyer, 1961 ; Garden and Mackenzie, 1963). Although treatment by this method gives good results, it should not be applied where a simpler method would suffice. I.P.P.R. is a severe strain on nursing staff, and because of its complexity carries a morbidity and even a mortality of its own. We have found it of practical value to consider the treatment of patients with chest injuries in three phases. (1) The emergency treatment of a number of conditions common to many chest injuries. These conditions include pain, pulmonary compression, paradoxical respiration, lung contusion, shock, and coexisting injuries. (2 shallow, and this (Ferris and Pollard, 1960) leads to a progressive fall in lung compliance owing to diffuse closure of alveoli throughout the lung substance. Pain prevents him from reversing this tendency by deep breathing.Pain can be controlled by conventional analgesics with or without antagonists and by thoracic segmental extradural block. We have used morphine alone and in combination with amiphenazole or tetrahydroaminacrine. Both these antagonists allow a larger dose of morphine to be given without respiratory depression. We have obtained good results with a combination of morphine 15 mg. and tetrahydroaminacrine 20 mg.Segmental thoracic extradural block (Simpson et al., 1961) involves the injection of local analgesic solution through a polyvinyl catheter placed in the thoracic extradural space. This provides complete relief from pain in the affected segments, and the restricted area of analgesia allows the use of small amounts of local anaesthetic solution, so that the fall in blood-pressure which accompanies an extensive extradural block is avoided. The relief from pain enables suitable patients to clear their lower airway by coughing and enables them to rest, and it improves morale. It will also, by allowing the patient to breathe more deeply and slowly, diminish the amount of paradoxical movement of a " floating " segment of chest wall. Continuous analgesia can be maintained by injections of lignocaine 1.50% through the catheter at intervals of 90 to 120 minutes, or by amethocaine (Pantocaine Plombe) at intervals of about three hours. An injection before physiotherapy allows coughing and deep breathing a...
