High frequency ventilation through a small catheter for laser surgery of laryngotracheal and bronchial disorders.

One-lung and two-lung high frequency ventilation (HFV) through a 2-mm internal diameter catheter was evaluated in 22 patients during endoscopic laser excision of stenotic lesions of larynx, trachea, and bronchi. High frequency ventilation at 80 to 250 breaths per minute using air during two-lung HFV and using air-oxygen at an inspired oxygen concentration of 25% during one-lung HFV maintained adequate alveolar ventilation and oxygenation in all patients. The use of HFV through a catheter allowed continuous control of ventilation and provided maximal surgical exposure for endoscopic laser surgery. The continuous outflow of HFV gases through the endoscope also prevented lung contamination with blood and debris. The potential of HFV polyvinylchloride catheter ignition by laser was also evaluated in the laboratory during continuous flow of air-oxygen and oxygen-nitrous oxide. The laser ignited polyvinylchloride tubes in all the mixtures of oxygen and nitrous oxide within 3 to 7 seconds. Oxygen at 30% mixed with nitrogen 70% was safe and all such tubes were not ignited by the laser. The ability of HFV to provide adequate oxygenation during endoscopic laser surgery using air-oxygen at an FiO2 below 30% also avoids the hazard of catheter and airway fire.

Continuous epidural infusion of morphine for treatment of pain after thoracic surgery: a new technique.

We evaluated postoperative pain relief and the incidence of side effects of three methods of thoracic epidural analgesia. Ninety patients, divided into three equal groups, received postoperative analgesia after thoracic surgery either as intermittent epidural injections of bupivacaine (25 mg/5 ml, 0.5% solution) as needed, or, intermittent epidural injections of morphine (5 mg/5 ml of normal saline, 0.1% solution) as needed, or continuous epidural infusion of morphine (0.1 mg, in 1 ml of normal saline) per hour supplemented with intravenous morphine (2 mg) upon request. Pain relief was evaluated by each patient on a pain scale visual analogue and by pain relief questionnaire for a period of 72 hr. Postoperative pain relief was achieved equally with these three methods of epidural analgesia in all patients with no significant difference between groups. Intermittent epidural injection of bupivacaine relieved pain for 4.9 +/- 1.9 (SD) hr/injection and was associated with urinary retention in all patients, with numbness and weakness of the hands in 12 patients, and with severe hypotension in 7 patients. Intermittent epidural injection of morphine relieved pain for 5.8 +/- 2.3 hr/injection and was associated with urinary retention in all patients, with pruritus in 12 patients, and with central narcosis and respiratory depression in 8 patients. Continuous epidural infusion of morphine with occasional intravenous morphine (2 mg) supplementation also effectively relieved postoperative pain and was associated with minimal systemic side effects. One patient complained of pruritus, and two patients developed urinary retention.(ABSTRACT TRUNCATED AT 250 WORDS)

High-frequency ventilation with an uncuffed endobronchial tube. A new technique for one-lung anesthesia.

Conventional one-lung intermittent positive-pressure ventilation (OL-IPPV) has been a valuable technique during anesthesia for intrathoracic operations. OL-IPPV has been associated with a high incidence of hypoxemia, as a result of the associated intrapulmonary shunt of 21% to 65% of cardiac output. The administration of OL-IPPV requires the use of a large cuffed endobronchial double-lumen tube. These tubes can be difficult to position properly and have been associated with malfunction, trauma, and tracheobronchial rupture. In an effort to avoid the problems associated with conventional OL-IPPV, we have developed a new technique of modified one-lung high-frequency ventilation (MOL-HFV). MOL-HFV is based on the administration of high-frequency ventilation (HFV) through a small uncuffed endobronchial tube. MOL-HFV was studied in 26 patients during a variety of intrathoracic surgical procedures, and it was compared to one-lung high-frequency ventilation (OL-HFV) and OL-IPPV in each patient. After the chest was opened, each patient received a sequence of OL-IPPV, OL-HFV, and MOL-HFV. Arterial PO2 was measured and intrapulmonary shunting was calculated after 30 minutes of each type of ventilation. This study showed that arterial PO2 was significantly higher during MOL-HFV (mean 379 mm Hg) than during OL-HFV (mean 235 mm HG) or OL-IPPV (mean 141 mm Hg). This was the result of a significantly lower intrapulmonary shunt during MOL-HFV (19%). We conclude that MOL-HFV through a small uncuffed endobronchial tube provides better oxygenation, optimal surgical access, and avoids the problems associated with the use of double-lumen tubes.