Dean H. Morrow

The Tracheal Bronchus: An Unusual Airway Problem

REPORT OF A CASE A 2-year-old girl was admitted to the hospital with a history of recurrent croup. The child had experienced recurrent pulmonary infections, bronchiolitis, and asthma since 2 months of age. At the time of admission, the mother described fairly characteristic croup symptoms which seemed to coincide with periods of moderate exercise. The past medical history was negative except for several hospitalizations related to the present illness. Approximately 1 year before the present admittance, cardiac catheterization had ruled out a left pulmonary arterial vascular ring.

The effect of mepivacaine, bupivacaine, and lidocaine on digitalis-induced ventricular arrhythmias.

HERAPEUTIC management of ventricular T arrhythmias is a constant challenge. As the anesthesiologist becomes increasingly involved in patient care outside the operating room and becomes more familiar with moment-to-moment electronic patient-monitoring systems, he becomes increasingly aware of the need for a better understanding of the pharmacology of antiarrhythmic drugs. Although there is no single ideal arrhythmia suppressant, drugs which fall into this category can be assessed in terms of therapeutic efficacy as compared with systemic toxicity.

Anaphylaxis: etiology and guidelines for management.

The successful management of anaphylaxis requires a thorough understanding of this syndrome and the application of various therapeutic agents. Although the mechanisms responsible for human anaphylaxis are not fully known, sufficient data and clinical experience are available to guide the anesthesiologist faced with this medical emergency.

Anesthesia and digitalis toxicity. II. Effect of norepinephrine infusion on ouabain tolerance.

N A PREVIOUS report,l we presented eviI dence indicating that the relationship between the therapeutic and toxic levels of digitalis may be significantly modified by anesthetics. These experimental studies compared the digitalis tolerance of trained awake dogs to that of dogs anesthetized with halothane, cyclopropane, or pentobarbital. The dose of ouabain required to produce multiple premature ventricular contractions was increased by halothane, decreased by cyclopropane, and unaltered by pentobarbital. The lethal dose of ouabain was higher in dogs anesthetized with halothane than in dogs anesthetized with either cyclopropane or pentobarbital.

Antiarrhythmic Anesthetic Action. II. The Effect of Methoxyflurane on Ventricular Automaticity

During the course of surgical anesthesia, the majority of patients experience some arrhythmias, virtually all of which can be attributed to changes in cardiac pacemaker automaticity and/or alterations in cardiac conduction velocity. Therefore, a better understanding of these mechanisms is of importance to anesthesiologists.Cardiac automaticity in the intact heart of dogs under methoxyflurane anesthesia was assessed by measuring changes in ventricular escape time (VET) and ventricular escape rate (VER). A slight shortening of VET was noted, while there was virtually no change from control in VER.Unexpectedly, however, a nonsinus supraventricular escape focus became prominent in many animals at a low anesthetic dose and in all animals at a higher anesthetic concentration. This effect was shown to be preventable by pretreatment with reserpine or a beta-blocking agent.It is concluded that methoxyflurane increases the automaticity of parts of the atrial conducting system, other than the sinus, either by a direct effect or by increasing the sensitivity to prevailing background adrenergic levels.

The Effect of Protein-Synthesis Inhibitors on Anesthetic Action

Dixon and Fouts‘ attributed a prolonged central nervous system effect of hexobarbital following chloramphenicol administration to a decreased rate of barbiturate detoxification by the liver, such as that produced by SKF 525A (proadifen). On the other hand, Knapp and Mejia? found that neither SKF 525A nor carbon tetrachloride prolonged the blockade produced by local anesthetics, as did systemic pretreatment with puromycin, dactinomycin, acetoxycycloheximide (AXM) , cycloheximide, and chloramphenicol. Their studies, therefore, supported the hypothesis that recovery of nerve tissue from conduction blockade may depend, at least in part, upon the neosynthesis of some neuronal protein independent of any hepatic effect.

Anesthesia and digitalis toxicity. IV. Relationship of digitalis tolerance to catecholamines during cyclopropane or halothane anesthesia.

VIDENCE has been presented1 indicating E that digitalis tolerance is decreased by cyclopropane and increased by halothane anesthesia. Since many preoperative patients receive maintenance doses of cardiac glycoside, and since it is occasionally necessary to digitalize patients acutely during anesthesia, it was considered important to establish the mechanism whereby these anesthetics modify cardiac glycoside toxicity.

Anesthesia and digitalis toxicity. 3. Effect of lidocaine on ouabain-induced ventricular tachycardia.

During the past 3 years intravenous lidomine has been employed almost exclusively in this clinic for the treatment of ventricular arrhythmias occurring during anesthesia and surgery. Preference for this particular agent has been based upon its clinical efficacy and upon the observations of Harrison and coworkers9 who demonstrated in patients that 1 to 2 mg. per kg. of lidocaine administered intravenously was as effective as procainamide in protecting the ventricle against arrhythmias, and that its antiarrhythmic properties were produced without concomitant depression of heart contractile force or systemic arterial pressure.

The Operating Room as a Physiology Laboratory

N 1903 Harvey Cushing described the clinI ical usefulness of pneumatic blood pressure measurements, and suggested that this technic be adopted as routine in the operating room. As a result of Cushing’s publication, a committee of the Department of Surgery at the Harvard Medical School was appointed to consider the merits of the RivaRocci method for blood pressure determination and its possible use in surgical diagnosis and treatment. The committee, after lengthy deliberations, decreed that . . . “the skilled finger was of much greater value clinically for the determination of the state of the circulation than any pneumatic instrument.” As a result of this report, Cushing’s proposal for using the Riva-Rocci apparatus was put aside.1 Despite this early condemnation, continued appreciation of the value of sphygnomanometry has now made such measurements routine.