The effect of general anesthetic agents on intraocular pressure.

General anesthetics may have diverse effects on intraocular pressure, possibly leading to serious complications such as vitreous loss and iris prolapse. Clinical and research findings on the effects of depolarizing and nondepolarizing agents are discussed, and methods of avoiding or counteracting adverse reactions are summarized.

[Hemodynamic effects of vecuronium in man]. / Effets hémodynamiques du vécuronium chez l'homme.

The cardiovascular effects of vecuronium (Organon NC 45 or Norcuron) in man were determined through different protocols using continuous recording of heart rate, arterial blood pressure and parameters obtained by a Swan-Ganz catheter. In healthy anaesthetized patients (n = 23), the effects of a dose of 0.1 mg X kg-1 pancuronium (group A) were compared to those of two doses of vecuronium: 0.1 mg X kg-1 (group B) and 0.3 mg X kg-1 (group C). Pancuronium induced an increase in heart rate (+12%), arterial pressure (+16%) and cardiac index (+8%). No change occurred with vecuronium. In patients under mechanical ventilation in an intensive care unit, we compared the effects of pancuronium 0.1 mg X kg-1 (group D; n = 10), d-tubocurarine (group E; n = 11), vecuronium 0.1 mg X kg-1 (group F; n = 9) and 0.3 mg X kg-1 (group G; n = 10). Pancuronium induced an increase in heart rate (+12%), arterial pressure (+8%) and cardiac index (+9%). d-Tubocurarine induced an increase in heart rate (+6%), a decrease in arterial pressure (-24%) and cardiac index (-17%). No change was observed after vecuronium 0.1 mg X kg-1. After vecuronium 0.3 mg X kg-1, the changes were minimal: a slight decrease in arterial pressure (-5%), a very slight (+3%) and transient (3 min) increase in heart rate were observed. The doses were approximately equipotent in groups A, B and C, whereas the dose of 0.3 mg X kg-1 in group G is about 10 times the 90% effective dose of vecuronium. In geriatric patients with per- or postoperative circulatory deficiency (group H; n = 10, mean age 83 yr), no hemodynamic side effects were observed. Vecuronium seems to be a non-depolarizing neuromuscular blocking agent devoid of cardiovascular side-effects at the generally usual doses.

Dual action of pancuronium on succinylcholine block.

The effects of pretreatment with both sub-paralyzing and paralyzing doses of pancuronium and d-tubocurarine, on the onset and duration of succinylcholine-induced neuromuscular blockade were evaluated and compared in 225 patients. D-tubocurarine antagonized both onset and duration of succinylcholine block, while pancuronium produced a dual effect, antagonizing the onset and potentiating the duration of succinylcholine block. Pretreatment with d-tubocurarine (0.07 mg/kg, 0.3 mg/kg and 0.6 mg/kg) increased the time to onset of succinylcholine paralysis from 28 to 118%, and decreased the duration from 16 to 37%. Pancuronium (0.02 mg/kg, 0.04 mg/kg and 0.08 mg/kg) also antagonized the onset of succinylcholine paralysis with increases of 32 to 114%, but potentiated its duration from 30 to 103% compared with succinylcholine alone in the same patients. Although pancuronium markedly inhibited serum cholinesterase in vitro (I50=5 X 10(-7) mol) there was only a 10% inhibition of cholinesterase in vivo after pancuronium 0.08 mg/kg.

Prolonged curarisation following renal transplantation. A retrospective study.

A retrospective study of postoperative respiratory morbidity in 247 patients requiring renal transplantation between 1955 and 1973 showed that 7 patients required postoperative controlled ventilation for up to 6 days. The nondepolarising relaxants tubocurarine and pancuronium were used in only 65 patients, but all 7 cases of respiratory failure occurred in this group. This suggests that the use of these drugsin anephric patients is potentially hazardous so far as postoperative respiratory insufficiency is concerned.

Adverse effects of pancuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting.

Using a randomized double-blind protocol, the authors prospectively compared three nondepolarizing muscle relaxants with respect to their influence on hemodynamics and on the electrocardiogram. Thirty-three patients undergoing elective coronary artery bypass grafting (CABG) with high-dose (100 micrograms/kg) fentanyl anesthesia were studied. Patients received 1.5 X ED95 of either pancuronium (n = 12), metocurine (n = 9), or a metocurine-pancuronium combination (4:1 ratio by weight) (n = 12) for muscle relaxation. Heart rate and rate pressure product (RPP) were significantly higher postinduction in the pancuronium group. Myocardial ischemia, indicated by new ECG ST-segment depression occurred significantly more frequently, and exclusively, in the pancuronium group. The authors' data suggest that since pancuronium is associated with tachycardia and an increased incidence of myocardial ischemia, it is best avoided in patients with severe coronary artery disease undergoing CABG with high-dose fentanyl. Either metocurine or the metocurine-pancuronium combination provides greater hemodynamic stability, without precipitating myocardial ischemia, and can be safely and effectively substituted for pancuronium.

Anaphylactoid reactions during anaesthesia. Seven years' experience of intradermal testing.

Sixty one patients who had suffered intra-operative anaphylactoid reactions were studied. Intradermal testing identified the causative agent in 84% of cases and, in 75% of these, muscle relaxants were responsible. Predisposing factors in patients sensitive to muscle relaxants were: female sex, previous allergy and atopy. The incidence of previous exposure was considerably higher than that reported in the literature. Pancuronium is suggested to be the least likely currently available agent to provoke a major anaphylactoid reaction.

Relation of precurarization to suxamethonium to provide ease of intubation and to prevent post-suxamethonium muscle pains.

Tubocurarine 0.05 and 0.07 mg.kg-1, gallamine 0.1 and 0.2 mg.kg-1 and pancuronium 0.01 and 0.02 mg.kg-1 given three minutes before suxamethonium 1.0, 1.5 and 2 mg.kg-1 in groups of 10 patients each (total 210 patients) to compare ease of tracheal intubation and incidence of post-suxamethonium muscle pain. These were compared with a control group of suxamethonium 1.0, 1.5 and 2 mg.kg-1 given alone after thiopentone 5 mg.kg-1. On analysis, tubocurarine 0.07 mg.kg-1 and suxamethonium 2 mg.kg-1 was the ideal combination with the best intubation conditions and the lowest incidence of post-suxamethonium muscle pains. The second best combination was gallamine 0.2 mg.kg-1 and suxamethonium 2 mg.kg-1. Pancuronium 0.01 mg.kg-1 and 0.02 mg.kg-1 in combination with suxamethonium 2 mg.kg-1 were satisfactory, although less efficient than the combination with either tubocurarine or gallamine.

Ketamine-pancuronium-narcotic technic for cardiovascular surgery in infants--a comparative study.

Ketamine, pancuronium, and alphaprodine were used as the primary anesthetic agents in 71 infants requiring cardiovascular operations during a recent 1-year period. This group of patients was compared with a similar group anesthetized 3 years before with d-tubocurarine, halothane, and/or N20-O2. Stability of the circulatory system was well maintained with ketamine-pancuronium-narcotic (KPN) during the induction period. However, once surgical dissection of the heart and great vessels began, hypotension/bradycardia, ventricular fibrillation, and 48-hour mortality were similar for the two groups. Therefore, using these criteria for analysis, the KPN technic, in spite of claims for its minimal adverse effect on the cardiovascular system, did not prove superior to the halothane-N2O-O2-curare technic.

[L-tubocurarine and pancuronium bromide in open heart surgery]. / La d-tubocurarina e il bromuro di pancuronio in cardiochirurgia a cuore aperto

Comparison is made between 45 cases treated with d-tubocurarine and 60 with pancuronium bromide in open-heart surgery. Pancuronium displayed unmistakable advantages in the form of a more potent action, rapid commencement and long duration, dose flexibility and an almost complete absence of undesirable side-effects. In addition, it offered stability with respect to the cardiovascular system and enabled risk-free, deep muscle relaxation to be achieved even in subjects with complex cardiopathies, such as those with pulmonary hypertension, extreme hypoplasia or aplasia of the trunk of the pulmonary artery and patent ductus arteriosus, for whom a very high operative mortality risk exists when even minimal changes in cardiovascular parameters occur.

Comparison of muscle relaxants in clinical use.

A prospective clinical comparison of d-tubocurarine, alcuronium, gallamine and pancuronium was performed in 400 surgical patients. Various parameters usually followed during clinical anaesthesia were recorded from the beginning of, to the recovery from anaesthesia. Endotracheal intubation was performed with or without suxamethonium. Intubation was always possible in 1-3 min when different muscle relaxants were used in the following initial doses: d-tubocurarine 0.4 mg/kg, alcuronium 0.3 mg/kg, gallamine 1.8 mg/kg, and suxamethonium 0.8 mg/kg. However, there was a statistically significant inferiority of the d-tubocurarine and gallamine groups. The use of suxamethonium seemed to shorten the duration of the initial dose of the nondepolarising agents and also to increase especially the dose of gallamine when calculated as mg/kg/h. It should be mentioned that the non-depolarising agents were given soon after suxamethonium without waiting for the return of spontaneous respiration. Pancuronium and alcuronium caused least changes in the cardiovascular parameters. Erythematous skin reactions were seen mostly after the use of d-tubocurarine and suxamethonium. This could depend on histamine liberating potency of these muscle relaxants.

Cardiovascular effects of nondepolarizing relaxants employed for pretreatment prior to succinylcholine.

A pregnant woman with severe pre-eclampsia experienced a hypertensive crisis following a pretreatment dose (20 mg) of gallamine. That episode initiated a study to determine the cardiovascular effects of non-depolarizing muscle relaxants in 58 nonobese, ASA physical status I and II adults. Subjects were assigned randomly to one of five treatment groups as follows: gallamine (0.29 mg X kg-1), d-tubocurarine (0.04 mg X kg-1), metocurine (0.014 mg X kg-1), pancuronium (0.007 mg X kg-1), or normal saline (control). Baseline measurements of systolic, diastolic, mean arterial pressure, heart rate (HR) and rate pressure product (calculated RPP) were recorded at one-minute intervals while electrocardiogram, lead II, was recorded continuously. Statistically significant increases occurred in HR at minutes 2, 3 and 4; RPP at minutes 3 and 4; and per cent change in HR at minutes 2, 3 and 4 following gallamine pretreatment. The rise in RPP was predominantly due to the elevation in HR. These results suggest that even modest doses of gallamine should be avoided in clinical situations where lability of cardiovascular dynamics can be anticipated.