Physiology of respiratory system related to anesthesia.

All inhalational anesthetic agents depress respiratory function. They also depend largely on the respiratory system to facilitate an induction and emergence from anesthesia. The other anesthetic agents, such as intravenous agents, also depress respiration. Much of the morbidity and mortality that occurs in the perioperative period can be attributed to an alteration in lung mechanics and dysfunctions in airway dynamics. In fact, it is postulated that 70% to 80% of the morbidity and mortality occurring in the perioperative period is associated with some form of respiratory dysfunction. Consequently, a detailed discussion of the many facets of respiratory anatomy and physiology will be presented. If the CRNA incorporates this information into anesthesia practice, care of the surgical patient will be enhanced.

Pathophysiology of the respiratory system related to anesthesia.

The pathophysiology of the respiratory system can be viewed by simply evaluating the status of a functional residual capacity (FRC). More specifically, patients with airways that are characterized as extremely compliant or "floppy" will have an increased FRC, which is the hallmark of chronic obstructive pulmonary disease. Patients with noncompliant, "stiff" lungs suffer from a form of restrictive disease with a resultant reduction in the FRC. Hence, the implications for anesthesia care focus on the FRC; that is, raising the FRC in the restrictive disease patient and normalizing or preventing further increase in the FRC in the patient with chronic obstructive pulmonary disease.

The pharmacology of respiratory disorders related to anesthesia.

The pharmacology of disorders of the respiratory system focuses on one major parameter--bronchodilatation. Drugs are rated as effective purely on how well they reverse brochoconstriction. Patients' conditions are considered reversible if there is a 20% increase in flow rates after a bronchodilator is administered. This article evaluates many of the drugs used in the treatment of reactive airway diseases such as asthma. Particular emphasis is placed on the anesthetic drugs used during the perioperative period.

Anesthesia care of the patient with reactive airways disease.

The clinical characteristics of reactive airways disease have been recognized for centuries. Any bronchospastic respiratory disease process that has a degree of reversibility can be considered a reactive airways disease. More specifically, any of the chronic obstructive pulmonary disease components--asthma, emphysema, and chronic bronchitis--that are reversible can be considered a form of reactive airways disease. Asthma is the prototypical reactive airways disease. Accounts of asthmatic symptoms have appeared in the medical literature from the time of Hippocrates. In fact, the word asthma is derived from the Greek word "asthma," which means panting. Certainly, the anesthetic management of a patient with asthma can be challenging for the anesthetist. Serious complications, of which 75% are pulmonary, can occur both during and after surgery.

Comparison of two instructional methods on the levels of physiologic and psychologic stress as measured by blood cortisol and the State-Trait Anxiety Inventory.

This study was designed to determine whether a systematic or nonsystematic instructional strategy affected the levels of physiologic and psychologic stress as measured by blood cortisol levels and the State-Trait Anxiety Inventory (STAI) in students in the postsecondary educational setting. A convenience sample consisting of 43 subjects was randomly assigned to either a systematic or nonsystematic teaching group. The blood cortisol and STAI were measured 1 and 2 weeks before the treatment and following the treatment on the day of the study. Results of the study demonstrated that there were differential posttreatment increases in the amount of physiologic stress, as measured by blood cortisol levels produced by either instructional method. However, between the control measurement 1 week before the treatment and the posttreatment measurement, there were no effects observed for the psychologic STAI measures for either group. Accounting for the circadian rhythm effect of cortisol, there was a significant "buffering effect" in stress experienced by the subjects in the systematic teaching group. More specifically, the nonsystematic teaching group experienced a 55.42% rate increase in cortisol compared to a 10.74% rate increase for the systematic teaching group which was statistically significant. The systematic teaching method may be more effective in preventing physiologic stress in the educational setting and possibly in the clinical practice of anesthesia nursing. Additionally, the results suggested that the STAI may be inappropriate when used as an index of stress in certain educational settings.