Sore throat after operation: influence of tracheal intubation, intracuff pressure and type of cuff

One hundred and eighty-four patients were studied to elucidate the contribution of intracuff pressure and cuff type to the occurrence of sore throat and hoarseness after operation. The patients were allocated to one of the following groups: A = mask only; B = reusable Rüsch tube with intermittent cuff volume adjustment; C = reusable Rüsch tube without cuff volume adjustment; D = disposable Portex Blue Line tube with intermittent cuff volume adjustment; E = disposable Shiley Low Pressure tube with intermittent cuff volume adjustment. Nitrous oxide was a component of anaesthesia in all patients. Moderate or severe symptoms were recorded in 30-33% of the patients in groups C, D and E, contrasting with group B, in which these sequelae were seen in only 10% of patients (P less than 0.025). All sequelae occurred less frequently in group A than in any of the other groups (P less than 0.025). Women were more likely to develop sore throat after intubation than were men (P less than 0.01). A possible relationship between differences in cuff-trachea contact area is postulated.

Thiopental-nitrous oxide- halothane anesthesia and repeated succinylcholine: comparison of preoperative glycopyrrolate and atropine administration

The effects of glycopyrrolate and atropine given prior to thiopental-N2O-halothane anesthesia on bradyarrhythmias associated with the administration of succinylcholine were studied and compared. Sixty healthy adult patients were allocated at random to one of three groups. Three minutes before induction of anesthesia with thiopental (4 to 5 mg/kg) one group received glycopyrrolate, 0.0045 mg/kg IV, the second group, glycopyrrolate, 0.008 mg/kg IV, and the third group, atropine, 0.009 mg/kg IV. Succinylcholine, 1 mg/kg of body weight, was given 1 minute and 6 minutes after the conclusion of the thiopental injection. ECG monitoring was continuous, and serum K+ levels as well as PaO2 and paCO2 were repeatedly measured. In all three groups patients were adequately and equally protected against serious bradyarrhythmias following the second dose of succinylcholine by atropine and glycopyrrolate in the doses used.

Effects of nitrous oxide on systolic time intervals

The effects of inhalation of oxygen, nitrous oxide/oxygen and nitrous oxide/nitrogen/oxygen on systolic time intervals (PEP (pre-ejection period) and LVET (left ventricular ejection time) were investigated in eight healthy persons. Nitrous oxide 40%, administered with oxygen or oxygen/nitrogen, prolonged PEP significantly by 25% and 22%, respectively. Inhalation of oxygen also prolonged PEP but to a significantly minor degree. LVET, heart rate and MAP were unchanged during the experiments. Derivatives from the systolic time intervals, i.e. PEP/LVET, I/PEP2 and ejection fraction changed significantly in the nitrous oxide groups. It is concluded that nitrous oxide depresses cardiac performance, to some degree, even when administered at a rather low concentration.

Effects on muscarinic receptors of various agents in reversal of neuro-muscular blockade: a study evaluating atropine, glycopyrron, neostigmine and pyridostigmine

The effects were studied of various drug combinations, recommended for use in reversal of neuromuscular blockade, on heart rate and salivary secretions in 80 healthy patients anaesthetized with nitrous oxide-oxygen-halothane and relaxed with d-tubocurarine. The drug combinations were mixtures of atropine 1 mg--neostigmine 2.5 mg, atropine 1 mg--pyridostigmine 15 mg, glycopyrron 0.5 mg--neostigmine 2.5 mg, and glycopyrron 0.5 mg--pyridostigmine 15 mg, respectively. It was found that administration of the atropine-containing mixtures induced more pronounced initial increases and delayed decreases in heart rate than the mixtures containing glycopyrron. Pyridostigmine-containing mixtures elicited a somewhat more pronounced initial increase in heart rate than neostigmine-containing mixtures, but a less pronounced and delayed decrease in heart rate. Supraventricular arrhythmias occurred less frequently in the pyridostigmine groups than in the neostigmine groups. No such difference was found between the atropine and glycopyrron groups. Glycopyrron caused a more intense dryness of the mouth than atropine. A differential attitude towards the use of drugs for reversal of neuromuscular blockade, based on the cardiovascular state of the particular patient, might be recommendable.

Changes in myocardial performance induced by pancuronium and gallamine in hypercapnic and hypocapnic dogs

Changes in myocardial performance after administration of gallamine 1.5 mg kg-1 and pancuronium 0.1 mg kg-1 were investigated in hypercapnic (PaCO2 = 7.08 kPa) and hypocapnic (PaCO2 = 2.74 kPa) dogs anaesthetized with thiopentone, nitrous oxide and halothane. Administration of pancuronium during hypocapnia caused a decrease of 25% in dP/dt max (corrected for changes in preload, afterload and heart rate). This change was not seen during hypercapnia, probably because of the associated sympathetic stimulation. By contrast, gallamine was without effect on dP/dt max in both groups. The increase in heart rate and cardiac output caused by the atropine-like action of both groups. The increase in heart rate and cardiac output caused by the atropine-like action of these relaxant drugs differed in the hypercapnic and hypocapnic group of dogs, with the more pronounced response in the latter group. The duration of the chronotropic changes was the same in both groups.

Some aspects of ocular function after precurarization

Small doses of nondepolarizing relaxants are often recommended as prior medication to suxamethonium in order to avoid or attenuate the side effects elicited by the latter drug. After D-tubocurarine (0.05 mg/kg b.w. and 0.075 mg/kg b.w.) in unmedicated volunteers, a dose-dependent recession of the monocular near point of accomodation was recorded. This recession, which parallelled the decrease in grip strength, was 4 cm and 9 cm, respectively. The same doses evoked an exophoria of 14 and 17 prism diopters, respectively. Intraocular pressure was significantly lowered by D-tubocurarine 0.05 mg/kg b.w., from 2.01 kPa (15.1 mmHg) to 1.64 kPa (12.3 mmHg), and by pancuronium 0.015 mg/kg b.w. from 1.90 kPa (14.3 mmHg) to 1.44 kPa (10.8 mmHg). The decreases lasted for 7 min. Gallamine 0.3 mg/kg b.w. also decreased intraocular pressure, but to a lesser degree, and with statistical significance only during the fourth minute after administration. Relaxation of extraocular muscles may change the slightly ovoid shape of the eyeball into a more spherical one, thereby inducing a fall in intraocular pressure and a recession of the near point of accommodation.

Effects of precurarization on the heart measured by systolic time intervals

The effects of precurarization, with or without prior atropine medication, on heart rate, systolic time intervals (preejection period (PEP) and left ventricular ejection time (LVET)) and derivatives from these were studied in 80 healthy patients before minor surgery. Atropine (0.5-0.7 mg i.v.) exerted a vagolytic action with no changes in systolic time intervals. D-tubocurarine (0.5 mg/kg b.w.) did not affect heart rate or systolic time intervals. Both gallamine (0.3 mg/kg b.w.) and pancuronium (0.015 mg/kg b.w.) increased heart rate due to the inherent vagolytic effect. Furthermore, a short-lasting decrease in PEP and an increase in LVET were demonstrated. Consequently, a fall in PEP/LVET and a rise in 1/PEP2 were induced, indicating an increase in cardiac pump performance. These changes were blocked by prior atropine medication, a result which is not easily explainable. Possible clinical implications are discussed.

Cleaning hydrophilic contact lenses: an overview

The composition of the major, critical component of the amorphous deposits forming on hydrophilic lenses during wear was identified and reported by Karageozian as basically proteinaceous in nature. The research surrounding the identification has produced animal and laboratory models for testing the parameteres involved in the protein deposition, as well as in its removal. A standardized system for classifying the protein deposits during and after formation, along with the experimental animal and laboratory models allows a relatively complete development of the predictive tests required for a compound or a product intended for use as a cleaner of hydrophilic lenses. These predictive tests have been run on several available cleaning systems as well as on a new one; the results indicate clearly that, unlike the available systems, the new system will safely remove deposits from hydrophilic lenses. The laboratory predictive test results have been borne out by clinical trial; the clinical results indicate the suitability of the new formulation and the predictive capability of the test models developed.