James O. Elam

Simplified airway management during anesthesia or resuscitation. A binasal pharyngeal system.

HE QUESTION: “Should most patients T given a general anesthetic for elective surgery be subjected to routine tracheal intubation?’ stirs controversy among surgeons and anesthesiologists. Intubation has become so well accepted as a simple and safe routine that the other alternative of airway management, a mask with oropharyngeal airway, appears to be used with decreasing frequency. Yet the significant incidence of sore throats following tracheal intubation is usually accepted with the argument that the prevention of hypoxia, hypercapnia, or aspiration outweighs this relatively short discomfort.

Prisms and fiber optics for laryngoscopy.

IRECT laryngoscopy, involving peroral D insertion of a straight or curved larynoscope blade, lifting the base of the tongue, raising the epiglottis sufficiently, and viewing the glottis, is a simple atraumatic procedure in most normal patients. However, in perhaps 5 percent of adults, this maneuver may be traumatic, due to a variety of anatomic features such as obesity, macroglossus, micrognathism, postirradiation distortion, and acute edema. In some patients, laryngscopy is actually impossible, even by a skilled practitioner. Therefore, several workers have attempted to lessen these difficulties and the associated trauma incident to line-of-sight viewing of the larynx by indirect laryngoscopy (prism or mirror) , l “blind” methods of intubation,‘ and the substitution of other methods of airway management, such as binasal pharyngeal procedures. ,4 The earliest report of indirect viewing of the glottis by a Iaryngeal mirror was described by Garcia in 1855. Prisms of glass were used for indirect viewing by MacKenziez in 1865 and by Janeway6 in 1913. In 1968, Huffmani applied a prism to the curved laryngoscope of Macintosh.x

Use of double nasopharyngeal airways in anesthesia.

An improved method of airway management employing two nasopharyngeal airways (fig. 1) has recently been reported from these departments.3 The binasopharyng a l airway (BNPA) , offering less resistance than a single NPA, also provides the means to connect to any breathing circuit just as a mask or endotracheal tube does. In contrast to the nasal mask long employed in dentistry, the BNPA prevents airway obstruction by the tongue. In a number of situations in which general anesthesia is indicated, the use of a mask is not feasible and intubation of the trachea is undesirable. This report summarizes evaluation, at the University of California, Los Angeles, of the use of the BNPA for such procedures.

A volumetric system for monitoring minimal respiration in man.

A microvolumetric noninvasive sensor is described for the monitoring of minimal respiration in adults, children, and infants. The monitor, designated a diaphragm sensor, has been applied since 1965 in the clinical management of optimal ventilation and relaxant drug administration. As an inspiratory monitor in the curarized patient, the sensor responds quantitatively to persisting spontaneous tidal volumes of 1 ml. or more. This minimal respiration is observed between controlled lung inflations. The monitor also indicates small outboard circuit leaks and responds to cardiac pulsations when respiratory deflections disappear after succinylcholine administration or hyperventilation. Applications include easy maintenance of ventilation near or below the patients carbon dioxide (CO2) apneic threshold despite curarization and the assessment of diaphragm paralysis when the CO2 drive is maintained slightly above threshold. In continuous routine use, the diaphragm sensor provides the anesthesiologist with a quantitative monitor of persisting spontaneous respiratory activity.

Catheter subarachnoid block for labor and delivery: a differential segmental technic employing hyperbaric lidocaine.

SERIES of spinal blocks was performed A recently for labor and delivery following discovery that remarkably low doses of hyperbaric lidocaine result in total doses which are a small fraction of those required for conventional midspinal, peridural, caudal, paraoervical, and pudendal blocks. The degree of sympathetic blockade encountered was insignificant, an important consideration in any regional method for the parturient.

CARBON DIOXIDE HOMEOSTASIS DURING ANESTHESIA. IV. AN EVALUATION OF THE PARTIAL REBREATHING SYSTEM

SUMMARY Complete removal of carbon dioxide from the bag in the partial rebreathing system is not obtained by inflow rates equal to the patients minute ventilation. Inflow rates comparable to the minute ventilation as measured before rebreathing, resulted in inspired concentrations between 1.2 and 4.2 per cent, averaging 2.0 per cent. The degree of carbon dioxide rebreathing produced by this system was greater with ether anesthesia than with opiate depression. In all patients, use of the method evoked increase in ventilation. Inflow rates of 15 LPM are not sufficient to prevent accumulation of carbon dioxide in all patients, and the commonly used inflow rate of 10 LPM may result in concentrations above 4 per cent of inspired carbon dioxide in spite of excessive hyperventilation.

The expired air ventilator

From the Department of Medicine, University of Buffalo School of Medicine, and the Department of Anestbesiology, Roswell Park Memorial Institute, Buffalo, New York. Tbis study was supported in part by funds provided under Contracts DA-49-oo7-MD-209 and DA-pg-oo7-MD-507 witb the Division of Research and Development, Ofice of the Surgeon General, Department of the Army, and by tbe Dent Family Foundation.