Journal of cardiothoracic anesthesia
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J Cardiothorac Anesth · Oct 1989
Continuous oxygen insufflation in addition to IPPV causes air trapping in a mechanical lung model.
It has previously been reported that continuous insufflation of either supracarinal or subcarinal oxygen in addition to intermittent positive-pressure ventilation (IPPV) in patients under general anesthesia, and in critically ill patients in the intensive care unit, causes increased proximal airway pressure, decreased systemic blood pressure, and decreased cardiac output. The investigators hypothesized that these deleterious hemodynamic effects were due to intrapulmonary air trapping, resulting in an increased distal intrapulmonary pressure and volume. The purpose of this study was to test this hypothesis in an appropriate mechanical lung model. ⋯ With each insufflation catheter system (sequences 3, 4, and 5), each incremental increase in insufflation flow rate resulted in significant increases in lung pressure and volume. Increasing expiratory times (sequences 6 and 7 compared with 3, 4, and 5) decreased lung pressure and volume. Increasing the airway diameter (sequence 8) had only slight effect on lung pressure and volume.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Cardiothorac Anesth · Oct 1989
Bilateral intrapleural regional analgesia for postoperative pain control: a dose-finding study.
Postoperative pain management for major abdominal or thoracoabdominal procedures requires bilateral multisegmental intercostal nerve blocks or epidural analgesia. This study was undertaken to examine the possible role of bilateral intrapleural regional analgesia (BIRA) and to select the proper dose for this new technique. Bilateral intrapleural catheters were inserted after surgery, using a Mancao dual-cannula system. ⋯ Patients in groups I and II received narcotic medication whenever they felt pain or discomfort. The duration of BIRA was considered to be from the injection of the drug until the time a narcotic was administered to the patient. Demographic variables, changes in BP and heart rate after surgery, frequency of narcotic administration during the first four postoperative days, and postoperative hospital stay were compared in groups I and II.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Cardiothorac Anesth · Oct 1989
The influence of fresh gas flow and inspiratory/expiratory ratio on tidal volume and arterial CO2 tension in mechanically ventilated surgical patients.
The relative importance of fresh gas flow and inspiratory/expiratory ratio in determining delivered tidal volume and PaCO2 was studied in anesthetized adult patients ventilated with a fixed ventilator bellows volume. The fresh gas flows studied were 2, 6, and 10 L/min, and inspiratory/expiratory ratio was either 1:2 or 1:4.5. Bellows volume and respiratory rate were held constant throughout the study. ⋯ These data demonstrate that altering either fresh gas flow or inspiratory/expiratory ratio can produce clinically significant perturbations in PaCO2 and tidal volume during anesthesia. These perturbations occur even if bellows volume is held constant. Furthermore, changes in inspiratory/expiratory ratio will affect these parameters to a greater degree as fresh gas flow is increased.
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J Cardiothorac Anesth · Oct 1989
Anesthetic management of abdominal aortic surgery: a retrospective review of perioperative complications.
The incidence of perioperative complications was retrospectively reviewed in 103 patients who underwent replacement of the abdominal aorta from 1981 to 1987. Eighty-nine of the patients had associated systemic diseases, with hypertension being the most frequent (63%). Ischemic heart disease and cerebrovascular disease had an incidence of 12% and 13%, respectively. ⋯ Deterioration in renal function occurred in 6 patients, but with no difference between groups. There were three perioperative deaths (2.9%), with two of them resulting from cerebrovascular accidents in patients with a history of cerebrovascular disease. The overall morbidity and mortality were independent of the anesthetic technique.
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J Cardiothorac Anesth · Oct 1989
The mechanism of nitrous oxide-induced changes in pulmonary vascular resistance in a dog model of left atrial outflow obstruction.
Nitrous oxide has been reported to increase pulmonary vascular resistance (PVR) in patients with pulmonary hypertension secondary to mitral stenosis. Additional data suggest this response involves sympathetic stimulation because the increase in PVR can be prevented by alpha-adrenergic and ganglionic blockade. Whether or not active pulmonary vasoconstriction occurs remains unclear. ⋯ The inspired gas was then changed to 67% N2O and 33% O2 for 10 minutes, and then returned to the N2/O2 mixture. Once baselines had been reestablished (about 10 minutes), phentolamine, 0.75 mg/kg, was administered, and the response to 10 minutes of N2O again observed. N2O did not change vascular resistance in the isolated lobe, but increased intact-lung PVR.(ABSTRACT TRUNCATED AT 250 WORDS)