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Effects of lidocaine on the central nervous system
470
INTERNATIONAL ABSTRACTSOF PEDIATRIC SURGERY
from 30 per cent to 60 per cent. When higher oxygen concentrations are required, the ventilator should be driven by oxygen.--John ]. Downes. EFFECTS OF LIDOQAINEON THE CENTRAL NERVOUS SYSTEM. I. H. Wagman, R. H. De Jong and D. A. Prince. Anesthesiology 28:155-169, January-February 1967. Studies of evoked potentials in cats and rabbits as well as changes in cortical activity indicate that intravenous lidocaine has diffuse effects on the central nervous system due primarily to an activating effect of lidoeaine on the amygdaloid nuclear complex. Factors affecting the threshold dosage of lidocaine necessary to produce a convulsion include animal species, basal anesthetics and transient hypotension. The threshold was also dependent on the Paco2 with a lower dose of lidocaine needed to produce a generalized electrical seizure in the presence of an elevated Paco2. This latter effect may be related to increases in cerebral blood flow, thus allowing more lidocaine to reach the brain per unit time, and to the direct excitation of the amygdaloid nucleus by carbon dioxide itself.--1ohn I. Downes. SUCCINYLCItOLINE DANGER IN THE BUI~NED PATIENT. H. D. Tolmie, T. H. ]oyce and G. D. Mitchell. Anesthesiology 28:467-470, MarchApril 1967. The increased incidence of cardiac arrest during anesthesia induction in the severely burned patient has been attributed to the vagal effects of succinylcholine, fluid depletion, acidosis and potassium efl]ux. A 19 year old marine sustained a 35 per cent third degree burn, requiring repeated administration of anesthesia for dressing changes and debridement. The first 10 anesthetics proceeded without event. The eleventh anesthetic induction, administered on the thirty-first pos~-burn day, consisted of thiopental, nitrous oxide-oxygen and 60 mg. succinylcholine intravenously. Following tracheal intubation cardiac arrest occurred. External cardiac massage, 1O0 per cent oxygen and intravenous sodium bicarbonate effected the return of normal circulation. Five days later, the same anesthetic technique was employed. Following succinylcholine, the T-waves became peaked and widened, and ventricular fibrillation followed. Resuscitation was quickly effective. At a subsequent induction of anesthesia, 40 rag. of succinylcholine was injected intravenously and elicited similar T-wave changes and a 9 second period of ventricular tachyeardia.
Serum potassium levels ranged from 6.5 to 8.5 m E q - L at 2 to 6 minutes after the intravenous succinylcholine. One subsequent anesthetic was carried out with the same fundamental technique except that gallamine, 100 rag. was employed as the muscle relaxant. Electrocardiogram showed no change whatever and the anesthesia proceeded without complications. It is concluded that severely burned patients may have an extraordinary release of potassium into the circulation after succinylcholine injection intravenously. Thus, gallamine would be a preferable muscle relaxant to facilitate tracheal intubation in such patients.--John 1. Downes. 1)ROLONGED NASOTRACHEAL ~NTUBATION IN INFANTS AND CHILDREN. W. G. Markham, M. 1. A. Blackwood and A. W. Conn. Canad, Anaesthetists Soc. J. 14:11-21, January 1967. A total of 156 children were intubated for 24 hours or longer, with 74 long-time survivors. The longest period that a tube was left in place was 43 days. Subglottic stenosis, however, subsequently developed in this patient. The longest period of intubatiou without complication was 28 days in an infant with tetanus. The smallest patient treated with prolonged intubation (4 days) weighed 1.5 kg. The authors conclude that infants and children can be more effectively ventilated using nasotracheal tubes than with untufted tracheostomy tubes.--Colin C. Ferguson. INTEGUMENT AND CONNECTIVE TISSUES LEVITATION IN THE TREATMENT OF LAacE-Am~A BUaNS. 1. T. Scale~, L. A. Hopkins, M. Bloch, A. G. Towers, and I. F. K. Muir. Lancet 1:1235, 1967. Scales and his co-workers present modifications of the bed used for levitation (the support of a body without visible means) which was demonstrated at the Second International Congress for Research in Burns, in Edinburgh, in 1965. Patients can be supported on an air cushion bed using pressures less than those which would obtain if supported in the normal way on buttocks and shoulders. The principle is based on the air seals for use on Hovercraft. The present bed, Mark F5b, has a flexible top with self-inflating pockets. It is essentially a plenum chamber with an outlet which is self-adjusting in 3 phases. After trials with volunteers, 2 patients were treated,
INTERNATIONAL ABSTRACTSOF PEDIATRIC SURGERY
from 30 per cent to 60 per cent. When higher oxygen concentrations are required, the ventilator should be driven by oxygen.--John ]. Downes. EFFECTS OF LIDOQAINEON THE CENTRAL NERVOUS SYSTEM. I. H. Wagman, R. H. De Jong and D. A. Prince. Anesthesiology 28:155-169, January-February 1967. Studies of evoked potentials in cats and rabbits as well as changes in cortical activity indicate that intravenous lidocaine has diffuse effects on the central nervous system due primarily to an activating effect of lidoeaine on the amygdaloid nuclear complex. Factors affecting the threshold dosage of lidocaine necessary to produce a convulsion include animal species, basal anesthetics and transient hypotension. The threshold was also dependent on the Paco2 with a lower dose of lidocaine needed to produce a generalized electrical seizure in the presence of an elevated Paco2. This latter effect may be related to increases in cerebral blood flow, thus allowing more lidocaine to reach the brain per unit time, and to the direct excitation of the amygdaloid nucleus by carbon dioxide itself.--1ohn I. Downes. SUCCINYLCItOLINE DANGER IN THE BUI~NED PATIENT. H. D. Tolmie, T. H. ]oyce and G. D. Mitchell. Anesthesiology 28:467-470, MarchApril 1967. The increased incidence of cardiac arrest during anesthesia induction in the severely burned patient has been attributed to the vagal effects of succinylcholine, fluid depletion, acidosis and potassium efl]ux. A 19 year old marine sustained a 35 per cent third degree burn, requiring repeated administration of anesthesia for dressing changes and debridement. The first 10 anesthetics proceeded without event. The eleventh anesthetic induction, administered on the thirty-first pos~-burn day, consisted of thiopental, nitrous oxide-oxygen and 60 mg. succinylcholine intravenously. Following tracheal intubation cardiac arrest occurred. External cardiac massage, 1O0 per cent oxygen and intravenous sodium bicarbonate effected the return of normal circulation. Five days later, the same anesthetic technique was employed. Following succinylcholine, the T-waves became peaked and widened, and ventricular fibrillation followed. Resuscitation was quickly effective. At a subsequent induction of anesthesia, 40 rag. of succinylcholine was injected intravenously and elicited similar T-wave changes and a 9 second period of ventricular tachyeardia.
Serum potassium levels ranged from 6.5 to 8.5 m E q - L at 2 to 6 minutes after the intravenous succinylcholine. One subsequent anesthetic was carried out with the same fundamental technique except that gallamine, 100 rag. was employed as the muscle relaxant. Electrocardiogram showed no change whatever and the anesthesia proceeded without complications. It is concluded that severely burned patients may have an extraordinary release of potassium into the circulation after succinylcholine injection intravenously. Thus, gallamine would be a preferable muscle relaxant to facilitate tracheal intubation in such patients.--John 1. Downes. 1)ROLONGED NASOTRACHEAL ~NTUBATION IN INFANTS AND CHILDREN. W. G. Markham, M. 1. A. Blackwood and A. W. Conn. Canad, Anaesthetists Soc. J. 14:11-21, January 1967. A total of 156 children were intubated for 24 hours or longer, with 74 long-time survivors. The longest period that a tube was left in place was 43 days. Subglottic stenosis, however, subsequently developed in this patient. The longest period of intubatiou without complication was 28 days in an infant with tetanus. The smallest patient treated with prolonged intubation (4 days) weighed 1.5 kg. The authors conclude that infants and children can be more effectively ventilated using nasotracheal tubes than with untufted tracheostomy tubes.--Colin C. Ferguson. INTEGUMENT AND CONNECTIVE TISSUES LEVITATION IN THE TREATMENT OF LAacE-Am~A BUaNS. 1. T. Scale~, L. A. Hopkins, M. Bloch, A. G. Towers, and I. F. K. Muir. Lancet 1:1235, 1967. Scales and his co-workers present modifications of the bed used for levitation (the support of a body without visible means) which was demonstrated at the Second International Congress for Research in Burns, in Edinburgh, in 1965. Patients can be supported on an air cushion bed using pressures less than those which would obtain if supported in the normal way on buttocks and shoulders. The principle is based on the air seals for use on Hovercraft. The present bed, Mark F5b, has a flexible top with self-inflating pockets. It is essentially a plenum chamber with an outlet which is self-adjusting in 3 phases. After trials with volunteers, 2 patients were treated,