Inability to elicit vagal responses from the acid-infused esophagus of pigs.

Acid application in the esophagus and esophageal distension were undertaken in pigs. One group (n = 9) had operatively induced esophagitis. The other group (n = 7) was normal. We found no discrepancy between the groups neither in inspiratory pressure nor in expiratory PCO2 nor in plasma concentrations of pancreatic polypeptide. The results indicate inability to elicit vagal responses from the acid-infused esophagus of pigs.

The incidence of cardiac arrhythmias and arterial hypotension subsequent to standardized surgical stimuli in patients undergoing thoracotomy. With reference to enflurane and halothane.

A main factor which might cause cardiac arrhythmias and arterial hypotension during thoracic operations is surgical manipulation around the pericardium and the lung hilus. Halothane and enflurane were compared as to the occurrence of arrhythmias and hypotension caused by standardized surgical stimulation. Twenty-eight patients scheduled for thoracotomy were studied. The patients were selected in randomized order, and the anaesthetic agent in use was unknown to the surgeon. ECG, intra-arterial blood pressure and central venous pressure were recorded continuously. Six patients in the halothane group (n = 14) and nine patients in the enflurane group (n = 14) developed premature atrial contractions and nodal rhythm, while nine patients in the halothane group and five in the enflurane group developed a fall in systolic blood pressure of more than 20 mmHg (2.7 kPa). No statistically significant difference in the occurrence of cardiac arrhythmias and hypotension was found between the two anaesthetic groups.

Cerebral blood flow during early cardiopulmonary bypass in man. Effect of procaine in cardioplegic solutions.

Cerebral blood flow (CBF), plasma procaine concentrations, and somatosensory evoked potentials (SSEP) were recorded in 2 groups of patients in whom either a high-procaine cardioplegic solution (Bretschneider's n = 29), or a low-procaine cardioplegic solution (St. Thomas', n = 13) was used. In the Bretschneider's group, marked changes in CBF occurred (p less than 0.001). Mean CBF was 27 (range 18 to 51) ml/(100 g X min) between sternotomy and the onset of extracorporeal circulation (ECC). A mean of 6 minutes after the onset of ECC, and before the administration of Bretschneider's cardioplegic solution, CBF increased to 39 ml/(100 g X min). After administration of the cardioplegic solution, CBF decreased significantly within the first 15 minutes, and then gradually increased to a mean of 68 (range 43 to 108) ml/(100 g X min). Cerebral blood flow was 45 ml/(100 g X min) just after ECC was stopped. Marked plasma procaine concentrations, up to 100 mg/l, were reached just after the infusion of Bretschneider's solution. The flow was significantly reduced (p less than 0.015) in patients with plasma procaine greater than or equal to 10 mg/l, when compared to patients with plasma procaine values less than 10 mg/l. In the St. Thomas' cardioplegic solution group the same reduction in CBF did not occur (p less than 0.02). Despite the depressant effect of procaine on CBF in the Bretschneider group, a consistent brain hyperperfusion was observed in all patients during hypothermic ECC if their blood pressure was sufficient to produce hyperemia. In rats (n = 6), during normothermia without extracorporeal circulation, the effect of procaine was much more pronounced. The CBF fell from a mean resting level of 108 ml/(100 g X min) to 68 and 54 ml/(100 g X min) after 15 and 35 minutes, respectively, of continuous infusion of Bretschneider's solution. The flow returned to the resting level about 40 minutes after termination of the infusion.

The effect of intranasally administered nitroglycerin on the blood pressure response to laryngoscopy and intubation in patients undergoing coronary artery by-pass surgery.

The effect of intranasally administered nitroglycerin (NTG) on the cardiovascular response to laryngoscopy and intubation was studied. Thirty patients scheduled to undergo coronary artery by-pass surgery under thiopentone, enflurane and pancuronium anaesthesia were randomly divided into three groups. Group I received lignocaine 1.5 mg/kg i.v. prior to laryngoscopy and intubation (control group). Group II received lignocaine 1.5 mg/kg i.v. and in addition 2 mg nitroglycerin (NTG) was given intranasally. Group III received only 2 mg NTG intranasally. In Group I laryngoscopy and intubation caused a significant increase in mean arterial pressure (MAP) (P less than 0.01), heart rate (HR) (P less than 0.01) and rate pressure product (RPP) (P less than 0.01) compared to preoxygenation values. In Group II and III MAP and RPP remained unchanged, whereas HR increased (P less than 0.01 and P less than 0.01 respectively). It can be concluded that intranasally administered NTG effectively attenuates the pressor response to laryngoscopy and intubation in patients presenting for coronary artery by-pass surgery and that it is more effective and convenient method than intravenous lignocaine.

Haemodynamic effects of intravenous procaine as a supplement to general anaesthesia in patients with valvular heart disease.

The effect of intravenous procaine, 2 mg/kg/min, on the cardiovascular function of nine patients scheduled for cardiac valve replacement was studied under enflurane-pancuronium anaesthesia. Procaine infusion was started after intubation during steady-state anaesthesia, and continued until start of cardiopulmonary by-pass. Systemic vascular resistance decreased steadily from 198.2 +/- 28.7 to 133.0 +/- 17.2 kPa X s/l (P less than 0.05). A simultaneous decline in mean arterial pressure from 10.13 +/- 0.68 to 7.47 +/- 0.48 kPa was observed (P less than 0.01). Cardiac index, heart rate, central venous pressure, pulmonary arterial mean pressure and pulmonary capillary wedge pressure were all unaffected by procaine as well as by surgical stimulation. It is concluded that continuous procaine infusion as an adjuvant to general anaesthesia effectively abolishes the hypertensive and tachycardiac response to surgical stimulation. The limiting factor in the amount of infused procaine appears to be the hypotension caused by vasodilation, not myocardial depression or convulsions.

Haemodynamic effects of calcium chloride administered intravenously to patients with and without cardiac disease during neurolept anaesthesia.

During neurolept anaesthesia, calcium chloride (15 mg/kg) was administered intravenously to two different groups of patients undergoing vascular surgery on the abdominal aorta. The patients in group I all suffered from cardiac disease and were treated with digoxin, while the patients in group II had no cardiac symptoms. Cardiovascular measurements were made during steady-state anaesthesia. In group I, CaCl2 increased cardiac index (CI) significantly while systemic vascular resistance index (SVRI) remained unchanged. Mean arterial pressure (MAP) increased. In group II, both MAP and SVRI increased while CI remained unchanged. No significant changes in heart rate were observed and no arrhythmias occurred. It is concluded that CaCl2 administered intravenously is an effective means of improving cardiac function when it is depressed by anaesthesia, underlying cardiac disease, or both.

Moderate hypotensive anaesthesia for reduction of blood loss during total hip replacement.

Thirty-two consecutive patients scheduled for total hip replacement were randomly allocated to receive either neurolept anaesthesia or halothane anaesthesia. In the halothane group, systolic blood pressure was reduced to 10.69-13.33 kPa in normotensive patients, and to 13.33-16.0 kPa in hypertensive patients by adjusting the inspired halothane concentration and using supplementary fentanyl when necessary. In the neurolept group, no attempt was made to reduce blood pressure below the level achieved with adequate anaesthetic doses of fentanyl and droperidol. The average peroperative blood loss in the halothane group was 809 ml (range 250-1700 ml); this was significantly lower than in the neurolept anaesthesia group in which an average blood loss of 1909 ml (range 600-4900 ml) occurred. Moderate hypotensive halothane anaesthesia is recommended as an anaesthetic technique for total hip replacement.

Cardiovascular effects of etomidate used for induction and in combination with fentanyl-pancuronium for maintenance of anaesthesia in patients with valvular heart disease.

The effects of induction of anaesthesia by etomidate 3 mg kg-1 followed by continuous infusion of etomidate 2 mg min-1, fentanyl 0.01 mg.kg-1 and pancuronium 0.1 mg.kg-1 were studied in ten patients with valvular heart disease. No haemodynamic changes were seen injection of etomidate, but after fentanyl was given there was a significant decline in cardiac index (10%), in mean arterial systemic pressure (20%), in systemic vascular resistance (14%), in left ventricular minute work index (27%) and in right ventricular minute work index (21%) compared to the control values. After supplementing with pancuronium, no further significant changes were seen. There was no significant change in the pulmonary vascular resistance during the whole study. In conclusion, it appears that etomidate is a safe intravenous agent, and is worth further study, in particular in patients with minimal cardiac reserve requiring high inspired oxygen tension.

Increase in extracellular potassium in the brain during circulatory arrest: effects of hypothermia, lidocaine, and thiopental.

The effect of temperature (37 degrees C, 28 degrees C, and 18 degrees C), 160 mg/kg lidocaine, and 40 mg/kg thiopental on the efflux of cellular potassium in the cerebral cortex during complete global ischemia was examined. Cerebral ischemia was induced in dogs on cardiopulmonary bypass circulation by stopping the pump. Potassium concentration was measured on the brain surface by a valino-mycine-membrane electrode, which in its response corresponded well to an inserted microelectrode. Hypothermia reduced the ischemic potassium efflux rate to about 50 per cent at 28 degrees C, and about 25 per cent at 18 degrees C. At all temperature levels lidocaine caused an additional reduction in the potassium efflux rate of about 50 per cent, probably by reducing membrane ion permeability in accordance with its local anesthetic action. Thiopental had no effect on the potassium efflux during ischemia. This study opens the possibility that lidocaine, like hypothermia, may provide protection of the ischemic brain.

Cardiovascular effects of pancuronium in patients anaesthetized with enflurane and fluroxene.

The effects of pancuronium on the blood pressure and pulse rate were investigated in patients anaesthetized with either fluroxene or ethrane prior to the surgical procedure. At surgical levels of fluroxene anaesthesia, pancuronium increased the blood pressure and pulse rate significantly. In the patients anaesthetized with ethrane, the blood pressure did not change and the pulse rate rose only temporarily and to a less significant level. Analysis of the changes in pulse rate shows that the greater increase produced by fluroxene was due in part to the initial bradycardic effect of this anaesthetic. However the consistent elevation of blood pressure in this group can only be explained by sympathetic stimulation produced by fluroxene and unmasked by pancuronium. Previous administration of atropine suppresses the effect of pancuronium regardless of the anaesthetic in use.

The cardiovascular effects of pancuronium during halothane and cyclopropane anaesthesia.

The effect of pancuronium 0.1 mg/kg i.v. on heart rate (HR) and mean arterial blood pressure were investigated in two groups of eight patients, each receiving inhalational anaesthesia with either halothane or cyclopropane. A more pronounced effect on HR in the cyclopropane group with a mean increase of 104% occurred. The mean increase in the halothane group was 54%. There was a statistically significant difference (P less than 0.05) between the HR increases The vagolytic effect of pancuronium and the influence of halothane and cyclopropane on the autonomic nervous system are discussed.

The cardiovascular effects of ketamine used for induction of anaesthesia in patients with valvular heart disease.

The effects of induction of anaesthesia by ketamine 2 mg.kg-1 were studied in six patients with valvular heart disease before tracheal intubation and operation. Cardiac index was unaffected because a mean decrease in stroke index was compensated for a mean increase in heart rate. A significant increase was found in mean arterial pressure, pulmonary arterial mean pressure, pulmonary capillary wedge pressure and central venous pressure. Systemic vascular resistance increased, but not significantly, whereas pulmonary vascular resistance increased significantly by more than 150 per cent. Right ventricular minute work index increased in all patients, and the increase was as much as 400 per cent. Left ventricular minute work index increased in four of the six patients, but the magnitude of the increase was not so marked. It is therefore concluded that ketamine causes pronounced pulmonary vasoconstriction and an undesirable strain on the myocardium. Such effects could prove deleterious in patients with limited functional reserve of the right ventricle.

Cardiovascular haemodynamics after induction of anaesthesia with althesin in patients with valvular heart disease.

The haemodynamic effects of the induction of anaesthesia with Althesin 0.1 ml.kg-1 were studied in eight patients with valvular heart disease before tracheal intubation and surgery. A 20 per cent reduction in stroke index was compensated for by an increase in heart rate of similar magnitude. Cardiac index, mean arterial, pulmonary arterial, central venous and pulmonary capillary wedge pressures and systemic vascular resistance were unaffected. Pulmonary vascular resistance declined by nearly 30 per cent. It is therefore conclude that Althesin causes only minimal cardiovascular depression in patients with valvular heart disease.

Cardiovascular haemodynamics during enflurane-pancuronium anaesthesia in patients with valvular heart disease.

The effects of enflurane-pancuronium anaesthesia on cardiovascular haemodynamics were studied before operation in six patients with valvular heart disease. A ten per cent decline in cardiac index and a 20 per cent decline in stroke volume were the only changes observed. Mean arterial, pulmonary arterial, contral venous, and pulmonary capillary wedge pressures were unaffected, as were systemic vascular resistance and pulmonary vascular resistance. The authors therefore conclude that enflurane-pancuronium anaesthesia causes only minimal cardiovascular depression in patients with valvular heart disease.

Intravenous lidocaine as a suppressant of persistent cough caused by bronchoscopy.

The effect of intravenous lidocaine in the treatment of persistent cough occurring after diagnostic bronchoscopies performed under general anaesthesia was investigated in a controlled clinical trial. The study comprised 28 adults patients, all of whom had regained consciousness after anaesthesia. Fifteen patients were treated with lidocaine (1.05 mg/kg body weight) and 13 patients with placebo (saline). In each patient the intravenously injected dose was repeated once after 5 min. In 11 of the 15 patients (73%) who received lidocaine coughing ceased, while it continued in all 13 patients in the placebo group. The difference is highly significant (P less than 0.001). None of the patients developed side effects such as hypotension, arrhythmias, central nervous system symptoms or respiratory depression after injection of lidocaine. It is therefore concluded that intravenous lidocaine in man is a safe and useful cough-suppressant.

The effect of propanidid on systemic vascular resistance in man.

We have studied the peripheral vascular effect in man of propanidid 6 mg/kg, administered as a bolus injection during cardiopulmonary by-pass with the aorta cross-clamped and at constant perfusion flow. Ten measurements in eight patients were performed. A decrease was found in systemic vascular resistance: from 150.7 +/- 16.3 to 99.5 +/- 10.1 kPa x s/1. No venous pooling occurred. It is concluded that, in man, propanidid causes a vasodilation which must contribute to the hypotension it causes.

Percutaneous catheterization of the internal jugular vein.

Two techniques for catheterization of the internal jugular vein are described in detail. In a group of 108 adults and 54 children, catheterization of the internal jugular vein was attempted 168 times. Failure to achieve catheterization occurred 12 times. The success rate for the first 50 patients was 86%, but it increased with experience, and was nearly 96% for the remaining patients. Almost 90% of catherizations were achieved on the first or second attempt. The success rate was understandably lower in the children's group. Catheter malpositioning occurred infrequently (six times) and was most common in the children's group. There were few complications, although two were of a serious nature. The techniques described are straightforward, easy to master and perform, and are recommended as useful additions to the anaesthetist's clinical armamentarium.

Haemodynamic effects of enflurane in patients with valvular heart disease.

In eight patients undergoing cardiac surgery for aortic and/or mitral valvular disease, mean arterial blood pressure (MAP), central venous pressure (CVP), cardiac index (CI), stroke index (SI), pulmonary capillary wedge pressure (PCWP), and pulmonary arterial mean pressure (PAMP) were measured after premedications with diazepam-scopolamine (I), after breathing 100% oxygen (II), and on controlled respiration (III) after induction of anaesthesia with enflurane-O2, and endotracheal intubation facilitated by succinylcholine. All measurements were done prior to surgery. Enflurane anaesthesia was found not to affect cardiac index. The average SI decreased by 27%, but was compensated for by an average increase in heart rate (HR) of 33%. The average systemic vascular resistance (SVR) decreased by 14%. All other measured parameters were found to be unaffected by enflurane-O2 anaesthesia. It is concluded that the cardiovascular stability observed in healthy young normals during enflurane anaesthesia is preserved in patients with moderate to severe heart failure, making enflurane an anaesthetic agent well suited for patients with cardiac disease.

Heart rate changes caused by enflurane and halothane anaesthesia in man.

Changes in heart rate and arterial pressure caused by enflurane and halothane anaesthesia were investigated in patients premedicated with diazepam and scopolamine. Enflurane caused a significant (12%) increase in heart rate and depression of arterial pressure (23%). Halothane depressed heart rate significantly (14%), whereas arterial pressure was unaffected. The authors conclude that enflurane possesses a positive chronotropic effect.