Comparative physiological study of arbutamine with exercise in humans.

Pharmacological stress testing may be used in the diagnosis of coronary artery disease when there are contra-indications to the use of conventional exercise protocols. The responses to such testing using arbutamine and to conventional treadmill exercise were compared in eight patients. Respiratory gas analysis and cardiovascular observations were performed during both tests. For an equivalent increment in heart rate, both protocols increased systolic blood pressure and serum lactate. Minute ventilation and oxygen consumption also rose during both protocols, but much more so with exercise. The end-tidal partial pressure of CO(2) [35.1 (S.D. 3. 1) to 30.8 (6.6) mmHg] and the dead space/tidal volume ratio (V(D)/V(T)) [0.37 (0.09) to 0.33 (0.08)] fell significantly during arbutamine infusion, but the respiratory exchange ratio did not change during either protocol. Oxygen pulse, a marker of stroke volume, did not change significantly after arbutamine, but rose markedly after exercise [arbutamine, 3.9 (1.1) to 3.37 (0.7) ml. min(-1).beat(-1); exercise, 4.7 (1.4) to 16.1 (4.6) ml.min(-1). beat(-1) (P<0.0001 compared with baseline); difference between peak responses: P<0.0001]. We conclude that arbutamine simulates some of the physiological responses to exercise, although a number of these responses are less marked than during conventional exercise, in particular cardiac output (oxygen pulse). An increase in ventilation is produced, possibly due to direct stimulation of arterial chemoreceptors. These data suggest that the main action of arbutamine is to increase central drive rather than to establish peripheral demand.

Exhaled nitric oxide during incremental and constant workload exercise in chronic cardiac failure.

BACKGROUND: Nitric oxide (NO) is present in exhaled breath and produced by the pulmonary vascular endothelium as a potent vasodilator. Exercise is normally associated with pulmonary vasodilatation and a decrease in pulmonary vascular resistance to accommodate the increase in cardiac output. If production of NO is impaired in patients with chronic congestive cardiac failure (CCF), this might contribute to their exercise intolerance. PATIENTS AND METHODS: We quantified NO production (V NO) in 12 patients with chronic stable CCF and 12 controls, at rest and during incremental cardiopulmonary exercise on a treadmill, and at a later date during constant workload exercise. RESULTS: Patients had reduced V NO compared with controls during incremental exercise [381 (180) vs. 777 (275) nL min-1; mean (SD); P < 0.0001] but at constant workload V NO was similar between the two groups [353 (124) vs. 389 (189) nL min-1; P = 0.25]. Plasma levels of nitrate, the stable end-product of NO production, were significantly higher in patients [resting value 46.1 (21.6) vs. 23.0 (10.0) microM; P = 0.004] and were not influenced by exercise. CONCLUSION: Impaired NO-mediated pulmonary vasodilatation does not appear to contribute to exercise limitation in CCF. Alternatively, the lower NO production observed during maximal exercise in the patient group compared with controls may reflect a reduced incremental response of a system that is already abnormally activated in heart failure.

Cost-effective anesthesia: desflurane versus propofol in outpatient surgery.

This study compared the costs of desflurane and propofol as maintenance anesthetic agents in outpatient surgery. Recovery time and related drug expenses were included in the cost comparison. Fifty-three ASA physical status I and II patients were randomly assigned to receive a maintenance anesthetic of either desflurane with 50% nitrous oxide or propofol with 50% nitrous oxide. All patients received a propofol induction and were administered narcotics, sedatives, muscle relaxants, reversal agents, and antiemetics as determined necessary by the anesthesia provider. The mean propofol cost was $31.88 +/- 14.44, whereas, the mean desflurane cost was $12.99 +/- 7.61 (P < .05). The mean cost of all medications, anesthetics, and ancillary agents included was $57.97 +/- 20.22 for the propofol group and $34.86 +/- 14.13 for the desflurane group (P < .05). Of the desflurane patients, 41% experienced nausea compared to 12% of the propofol patients (P < .05). There was no significant difference between the recovery times of the two groups. Desflurane was more cost-effective than propofol. Although desflurane patients experienced more nausea, this did not affect their discharge time.

Results of a survey of nurse anesthesia education programs: diversity, growth and regionalization.

This survey was conducted in June of 1990. Questionnaires were sent to and data obtained from all civilian and military nurse anesthesia education programs. Programs were asked to provide the following information: type of conducting institution; the party responsible for the administrative costs of the program; name and location of the program's academic affiliation; the name, location, type and purpose of all clinical affiliations/sites; and distance from the conducting institution to the academic affiliation and to each clinical site. The conducting entities for civilian programs were as follows: hospital or medical center, 43 programs; academic institution, 15 programs; joint arrangement between a hospital and an academic institution, 10 programs; freestanding, 4 programs; other, 7 programs. For purposes of this survey, each branch of the military was considered to have a single program with multiple clinical sites. Two military programs identified their conducting entity as a joint arrangement between the respective branch of the military and an academic institution. The third program identified itself as freestanding with an academic affiliation. In all but seven programs, the administrative costs of the program are the responsibility of the conducting institution. The majority of programs (74%) have an academic affiliation and 68% of programs offer a graduate degree. Eighty percent of programs with an academic affiliation are located within 50 miles of the academic site. The greatest distance between a program and its academic affiliation is 350 miles. Programs reported having from 1-13 clinical sites (mean = 3.6 sites/program). Military programs, freestanding programs and programs conducted by an academic institution have the highest mean number of sites per program.(ABSTRACT TRUNCATED AT 250 WORDS)

Postoperative respiratory complications in non-idiopathic scoliosis.

The medical records of 303 patients undergoing fusions for scoliosis correction were retrospectively reviewed. The frequency and type of postoperative respiratory complications were compared in idiopathic versus non-idiopathic scoliosis patients in relation to age, type of spinal fusion procedure, pulmonary function test (PFT) results and preoperative diagnoses. The following factors were found to increase the incidence of problems in the postoperative period: a non-idiopathic type of scoliosis, mental retardation, anterior spinal fusion procedures, age of 20 or more years, a relative arterial hypoxemia and an obstructive component to the PFT's. Topics for further investigation are suggested.