Anaesthetic management of tracheal surgery using the neodymium-yttrium-aluminium-garnet laser.

A new technique for the management of tracheal or bronchial lesions (tumours or stenosis) using the NdYAG laser and bronchoscopy, was used in 55 patients without complications. The anesthetic problems are discussed. In some circumstances the procedure may be performed using sedation and topical anaesthesia. In most, general anaesthesia was used, controlled ventilation being achieved through the bronchoscope using a modification of the Sander's injector with mixture of 50% nitrogen and oxygen to avoid the risk of fire.

[Trans-sphenoidal pituitary resections. Various problems in anesthesia and resuscitation. Study in 1,193 cases (author's transl)]. / La chirurgie trans-sphénoïdale. Problèmes posés à l'anesthésiste-réanimateur. A propos de 1193 cas.

In the present study based on 1,193 cases of trans-sphenoidal pituitary resections, the various problems involved in anaesthesia and pre and post-operative care are discussed. The anaesthetic complications are few and should be avoided through adequate preparation and supervision. The procedure is a short one (75 +/- 16 minutes) and blood loss minimal. The patients are usually young (42 +/- 4 years old), in good condition (90% were in ASA group I or II). The pre and post-operative management must follow some well defined principles, based on hormonal substitution and diagnosis and early treatment of a possible diabetes insipidus.

[Air embolism in neurosurgery. General data (author's transl)]. / Embolies gazeuses en neurochirurgie. Données générales.

Air embolism in neurosurgery, in the sitting position, are not rare. They depend on the type of surgery (more frequent in operations on the posterior fossa), on the mode of ventilation, and most of all on the criteria for detection (clinical, electrocardiographic, ultrasonic, capnographic of haemodynamia). They depend as well upon the degree of tilt, of intrathoracic and intracardiac pressures (right auricle) and of the gas mixture administered (nitrous oxide increases their size owing to its poor blood solubility). The way of entry is venous, but it is certain that they can pass into the systemic circulation (their passage through the lungs is debated). According to their size, the speed of injection and the subject's previous condition they may affect: --the lungs: precapillary pulmonary artery hypertension, and even pulmonary oedema, --the heart, mainly through the fall of venous return, --the brain anoxia, followed by cerebral oedema, leading to early neurologic disturbances and possibly severe sequellae. Those symptoms are due to the gas embolism itself, but also to microthrombi of fibrin and disturbances of vascular membrane permeability.

[Anaesthesia in microsurgery of the larynx using a carbon dioxide laser, based on 665 cases (author's transl)]. / L'anesthésie pour la microchirurgie laryngée sous laser. A propos de 665 cas.

The authors describe their experience and emphasize the risk of ignition should inflammable gases be used less the cuff should burst, and its prevention by resorting to intravenous anaesthetic agents, and ventilating the patient with air or enriched air. They describe as well their experience with the Carden tube with jet ventilation with air.

[Pharmacology of nitroglycerin (author's transl)]. / Pharmacologie de la nitroglycérine.

Nitroglycerin is a vasodilating agent by virtue of its actions on vascular smooth muscle fibers. It may be administered intravenously (using either 5 p. cent dextrose, or propylene-glycol solvant), sublingually, orally or by topical administration. It is rapidly metabolized, principally by liver. Its is not toxic. The vasodilatation that is produced is both arterial and venous and is dose-related in dog (1 microgram to 100 micrograms/kg/min). However, resistance and tachphylaxis may occur. Its principal use is for angor treatment, but it has been used for the treatment of arteriopathy of the lower limbs, biliar hypertony and arterial hypertension. It has been recently administered for the treatment of acute phase of myocardial infarction and during pre, per- and post-operative periods in cardiac surgery, neurosurgery and hip surgery, as myocardial protector or anti-hypertensive agent or hypotensive agent. The absence of toxicity and the rapid reversibility of its cardio-vascular effects which are similar to the effects of sodium nitroprusside are important reasons for its use in anesthesia and cardiac intensive care.

[Clinical use of nitroglycerin as an hypotensive agent during general anesthesia (author's transl)]. / La nitroglycérine intraveineuse en solution aqueuse. Utilisation comme agent hypotenseur per-opératoire. Etude préliminaire sur 22 cas.

Nitroglycerine has a direct vasodilating action on both venous and arterial smooth muscle fibers. On account of this, it has been used as hypotensive agent, in aqueous solution, on 22 surgical patients, 10 of them in neurosurgery. The total doses used were 0.76 +/- 0.12 mg/kg during 94 +/- 30 minutes (rate = 8.1 microgram/kg/min). Nitroglycerine induces a rapid onset of hypotension (3 to 4 min), spontaneously reversible in 27 +/- 8 minutes after the arrest of the infusion. The mean drop in mean arterial blood pressure achieved has been 34 p. cent. It is accompanied by a 67 +/- 9 p. cent fall of filling pressures and a fall 13 +/- 4 p. cent of cardiac index, without modification of the heart rate. Tachyphylaxis was noted 15 +/- 6 minutes following nitroglycerine infusion at rate lower than 2 microgram/kg/min, but not when the rate was above 10 microgram/kg/min. Therefore, if the drug is used to achieve controlled hypotension, high doses are necessary. No signs of toxicity were noted. In 4 cases, other hypotensive agents had been used to bring the mean arterial blood pressure below 50 Torr, which could not be achieved with nitroglycerine alone.

[Nitroglycerin and amyl nitrite action on common bile duct during operation for vesicular lithiasis (author's transl)]. / Effects des dérivés nitrés sur le tonus des voies biliaires au cours de la chirurgie de la lithiase vésiculaire.

Eight patients undergoing cholecystectomy received a single injection of nitroglycerin (0,9 mg) and 8 received amyl nitrite, during a cholangio-kinesimetry. The maximum fall in common bile duct pressure was similar in both group; 3.2 +/- 0.3 torr after nitroglycerin (NTG),3.8 +/- 0.6 torr after amyl nitrite (AN). NTG caused a more persistent lowering of pressure than AN; 614 +/- 42 seconds/343 +/- 27 seconds (p < 0.001). This study showed that it is possible to produce a relaxation of biliary tract muscle fibres with an injection of nitroglycerin and then replace amyl nitrite during anesthesia.

Anaesthesia for microsurgery of the larynx using a carbon dioxide laser.

Microsurgery of the larynx using the carbon dioxide laser is becoming popular and provides many advantages. The anaesthetic management described here has proved successful in clinical use. Anaesthesia is induced with thiopentone and maintained by nitrous oxide and oxygen with or without halothane. Muscle relaxation is maintained using a continuous infusion of suxamethonium. Emphasis is laid on the need to protect the tracheal tube against the fire risk from the laser beam.

Cardiac arrhythmia induced by pneumoencephalography.

Cardiovascular collapse associated with pneumoencephalography (PNE) has been reported but there has been no prospective study of its nature and cause. We have recorded prospectively the e.c.g. of 82 unselected patients, with no cardiovascular or metabolic disease, undergoing PNE under general anaesthesia. The frequency of arrhythmia following air injection was 60%; bradycardia 22%; ventricular ectopic beats 26%; nodal rhythm or sinus tachycardia 11%. Cardiovascular collapse occurred in three patients; two with "torsades de pointes" and one with bigeminy and q.r.s. block. Arrhythmia was more frequent in patients with a pituitary tumour and intracranial hypertension (91%). Eight postoperative control PNE examinations were uneventful. Three of four patients with frontal lobe tumours and four of seven with posterior fossa tumours exhibited arrhythmia.