The patterns of endocrine response to surgical stress during different types of anesthesia and surgery in man.

The authors studied 123 patients undergoing minor (varicectomy) or major (cholecystectomy) surgery under diethyl ether, halothane, enflurane or hydroxydione anesthesia. The goal was to investigate the effects of emotional tension, anesthesia and surgical trauma, as well as glucose load, on the patterns of endocrine response under standardized clinical settings. The endocrine response (growth hormone, cortisol, insulin) was not modified significantly by emotional stress and the anesthetics used. Only prolactin was unique in that its release was markedly stimulated by halothane anesthesia. Neither the anesthetic drugs nor both types of surgical injury led to a constant hyperglycaemic response. Minor surgery failed to stimulate secretion of the studied hormones. However, major surgery stimulated growth hormone and cortisol secretion irrespective of the anesthetic used. Insulin secretion following glucose load was enhanced disproportionately. It is concluded that growth hormone level during surgical stress is determined by the extent and severity of surgical trauma, while neither anesthesia nor emotional tension exert any pronounced stimulative effect on its release. The observed changes in blood glucose levels and the lack of a proportionate insulin secretion are due to the effect of anesthesia rather than to that of surgery.

The effects of open heart surgery on growth hormone, cortisol and insulin levels in man. Hormone levels during open heart surgery.

Plasma growth hormone, cortisol, insulin and blood glucose concentrations were measured intra- and postoperatively in ten patients who underwent open heart surgery with moderate hypothermia. Diazepam-ketamine anaesthesia for 10-20 min failed to precipitate any significant alterations in the levels of measured hormones and blood glucose. In the pre-bypass period of surgery, an increase in cortisol and a slight elevation in growth hormone levels was observed; insulin level showed no change in spite of marked hyperglycaemia. The bypass period, including hypothermia and haemodilution, was accompanied by unchanged cortisol and elevated growth hormone levels, while insulin demonstrated a slight rise which did not correspond with the degree of hyperglycaemia. The post-bypass period with rewarming the restoring spontaneous circulation was characterized by further marked increase in cortisol and growth hormone levels and, in spite of decreasing levels of blood glucose, by a paradoxical elevation in plasma insulin. It is suggested that hypothermia, haemodilution, reduced tissue perfusion affecting endocrine glands, as well as denaturation of some hormones in the oxygenator, participate in the moderate endocrine response, disproportionate to the stress of cardiopulmonary bypass surgery. The rise in hormone levels on terminating bypass seems to be dependent on the improved blood flow to endocrine glands due to recovered spontaneous circulation, rewarming and, as for insulin, presumably even on the reduced inhibitory effect of catecholamines.

In vitro study of hormone degradation by heart-lung machine with bubble oxygenator.

In the present experiment with heart-lung machine set in a closed system in vitro, the blood containing increased levels of hormones was circulated at 30 degrees C for 90 min and at 37 degrees C for 30 min; a fraction of the priming perfusate was studied in parallel at the same temperatures in an incubator. The level of growth hormone decreased gradually to a mean of 76% at 30 degrees C and no further decrease was found at 37 degrees C. The mean insulin level fell within 30 min to 32% and no substantial further changes were observed during the remaining period of study; re-warming failed to produce significant additional changes. Cortisol did not change appreciably. However, the oxygenator altered the level of catecholamines markedly. At 30 degrees C the initial level of noradrenaline fell precipitously to 9% within 30 min and this excessively low level was sustained throughout the study. Adrenaline showed even more pronounced changes. Denaturation of dopamine was less marked falling to about 70% within 30 min. The present experiment revealed that the levels of hormones respond differently to artificial oxygenation during extracorporeal circulation. Cortisol resisted degradation by the oxygenator, while growth hormone and insulin were denatured significantly. The moderate degradation of growth hormone by the machine may not play an important role during open heart surgery. However, a marked oxidation denaturation of catecholamines by 90% and 70% and denaturation of insulin by 70%, might prove relevant during surgery.

Venepuncture, catheterization and failure to position correctly during central venous cannulation.

The authors analyse the incidence of puncture, catheterization and failures of positioning in a series of 420 central venous catheterizations performed in 388 patients, using six transcutaneous approaches: supraclavicular and infraclavicular subclavian, external and internal transjugular, antecubital and brachiocephalic. Puncture failures were recorded at 7.9% per 36 failures from 456 attempts, catheterization failures at 5.8% per 26 failures from 446 attempts, and misplacements at a rate of 5.7% per 23 misplacements during 420 catheterizations. The results show that, in respect of puncture, catheterization and success of positioning, the supraclavicular subclavian approach may be recommended preferentially. The internal jugular, brachiocephalic and infraclavicular subclavian approaches are also advantageous. A high rate of failures and misplacements was recorded in the antecubital and external jugular groups. The antecubital veins, however, should be reserved for orthopnoeic sitting patients, the success rate being significantly increased if the patients are sitting.

Surgical, infectious and thromboembolic complications of central venous catheterization.

The authors have analysed the incidence of specific complications in a series of 420 intracaval catheters placed in 388 patients, using six transcutaneous puncture techniques: supraclavicular and infraclavicular subclavian, external and internal jugular, antecubital and brachiocephalic approaches. Strict and moderate criteria were used to evaluate the frequency of complications. Using strict criteria, the lowest rate of surgical complications (5%) was found with the antecubital and external jugular approach, followed by infraclavicular (6.7%) and supraclavicular (9.3%) subclavian techniques; the highest rate was seen with internal jugular (10%) and brachiocephalic (15%) routes. As to inflammatory and infectious complications, the sequence was as follows: brachiocephalic (2.5%), infraclavicular (4.4%) and supraclavicular (5.3%) subclavian, and internal jugular (7%) veins; a 10% incidence was associated with external jugular and antecubital techniques. Manifest thromboembolic complications were observed only in the brachiocephalic and antecubital groups (2.5% and 10%, respectively), the overall incidence of pulmonary embolism being 0.2%. None of the approaches used can be recommended as an exclusive method of choice. The risks of central venous catheterization should be minimalized by adherence to strict principles of placing as well as care of the indwelling intravenous catheters.

Alpha-adrenergic control of growth hormone release during surgical stress in man.

The mechanisms involved in the initial release of growth hormone (GH) during cholecystectomy have been studied after the administration of phentolamine in saline and in isotonic glucose, and after the administration of 10% glucose. Infusion of these substances was started 10 min before and terminated 30 min after skin incision. The serum GH levels 30 min after skin incision in a nontreated control group were raised to 14.4 +/- 1.0 ng/ml. The alpha-adrenergic blockade by phentolamine (20 mg during 40 min) regardless of whether administered in saline or in isotonic glucose inhibited GH response to surgery (4.3 +/- 2.1 ng/ml, or 2.2 +/- 0.4 ng/ml). The administration of 10% glucose (40 g during 40 min) led to a diminished response in some, but not in all the patients (6.2 +/- 1.2 ng/ml). It is concluded that the alpha-adrenergic mechanism participates in GH response to surgery.

Inadvertent thoracic duct catheterization during transjugular central venous cannulation. A case report.

An aberrant placement of a central venous catheter into the upper part of the thoracic duct with loop formation in the left innominate vein was observed on catheterizing via the left internal jugular vein. The misplacement, which did not have any deleterious effects, was caused by the atypical insertion site of the thoracic duct at the dorsocaudal wall of the left innominate vein and, possibly, by its incompetent closing valve. The stiffness of the nylon catheter used may also have been a contributory factor. The possible causes of this complication of central venous catheterization are discussed. The preferential use of the right internal jugular vein is stressed.

Misplacement and loop formation of central venous catheters.

Exact placement is an essential prerequisite for long-term use of a central venous catheter. Reported data show an extremely wide range of catheteral misplacements: from less than 1% to more than 60%. Some approaches appear to be less advantageous than others, but the highest rates of misplacement occur in the cubital, external jugular and saphenous veins. A series is presented of 378 radiographically controlled central venous catheters analysed for aberrant placement and loop formation. The total occurrence of faulty positioning and coiling reached 5.3%, while the respective incidences were 30% for the external jugular vein, 5.7% for the internal jugular vein, 5.5% for the infraclavicular technique of subclavian venepuncture, 5.3% for the innominate vein and 1.4% for the supraclavicular approach of subclavian venepuncture. The total frequency for pure loop formation was 2.9%. The authors discuss numerous reported data on catheter malpositioning, according to the specific techniques used, and compare them with thier own results. The relatively low incidence in the present series is possibly due to the high proportion of cases where the supraclavicular subclavian approach was used, the omission of the sphrenous/femoral and cubital techniques, and to pre-determining the length of the inserted catheteral segments.

Respiratory failure as a seizure phenomenon. A case report.

Recurrent acute respiratory failure in an epileptic subject is described. The first episode of respiratory failure occurred while the patient was having frequent epileptic fits and was probably secondary to cerebral oedema with temporal herniation. The second occurred suddenly after 27 days during which the patient had been free from seizures. It is suggested that this episode of acute respiratory failure was the result of an epileptic seizure without any motor symptoms.