Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2001
Comparative StudyThe in vitro effects of remifentanil, sufentanil, fentanyl, and alfentanil on isolated human right atria.
Because some clinical studies have suggested that opioids used in anesthesia may have different deleterious hemodynamic effects, we compared the direct myocardial effects of cumulative concentrations of remifentanil, sufentanil, fentanyl, and alfentanil on inotropic and lusitropic variables of isolated human myocardium in vitro. Human right atrial trabeculae, obtained from patients scheduled for coronary bypass surgery or aortic valve replacement, were suspended vertically in an oxygenated (95% oxygen/5% CO(2)) Tyrode's modified solution ([Ca(2+)](o) = 2.0 mM, 37 degrees C, pH 7.40, stimulation frequency 1 Hz). The effects of cumulative concentrations (10(-11), 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) M) of remifentanil (n = 8), sufentanil (n = 8), fentanyl (n = 8), and alfentanil (n = 8) on inotropic and lusitropic variables of isometric twitches were measured. ⋯ Alfentanil induced a dose-dependent decrease in active isometric force and peak of the positive force derivative. This effect was abolished in the presence of [Ca(2+)](o) = 4.0 mM. None of these opioids altered lusitropic variables.
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Anesthesia and analgesia · Sep 2001
Learning endotracheal intubation in a clinical skills learning center: a quantitative study.
This study aimed to develop statistical models describing the learning of endotracheal intubation (ETI). We collected data from 100 subjects undergoing ETI training with intubatable medical models and manikins (airway trainers). Trainees initially viewed a video about ETI and an instructor demonstrated the technique. ⋯ Trainees became familiar with an airway trainer after multiple trials, as demonstrated by a 50% decrease in the odds of successful ETI when starting on a new trainer. The learning model indicated that a trainee learns about as much from 1 successful ETI as from 12 (95% confidence interval, 2-23) failed trials. The results demonstrate the feasibility of statistical modeling of the learning of ETI and provide insight into the learning process.
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Anesthesia and analgesia · Sep 2001
Case ReportsOpioid overdose in a patient using a fentanyl patch during treatment with a warming blanket.
This case describes the narcotic overdose associated with the use of a fentanyl transdermal patch in a patient being rewarmed with an external warming blanket during surgery. The clinical manifestation and the presumed pharmacokinetic mechanism responsible for the fentanyl overdose are discussed.
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Anesthesia and analgesia · Sep 2001
The efficacy of epinephrine or vasopressin for resuscitation during epidural anesthesia.
Cardiopulmonary resuscitation (CPR) during epidural anesthesia is considered difficult because of diminished coronary perfusion pressure. The efficacy of epinephrine and vasopressin in this setting is unknown. Therefore, we designed this study to assess the effects of epinephrine versus vasopressin on coronary perfusion pressure in a porcine model with and without epidural anesthesia and subsequent cardiac arrest. ⋯ After return of spontaneous circulation, bradycardia required treatment in animals receiving vasopressin, especially with epidural anesthesia. Systemic acidosis was increased in animals receiving epinephrine than vasopressin, regardless of presence or absence of epidural anesthesia. We conclude that vasopressin may be a more desirable vasopressor for resuscitation during epidural block because the response to a single dose is longer lasting, and acidosis after multiple doses is less severe compared with epinephrine.
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Anesthesia and analgesia · Sep 2001
The relationship between pneumatic tourniquet time and the amount of pulmonary emboli in patients undergoing knee arthroscopic surgeries.
Near-fatal pulmonary embolism can occur immediately after tourniquet release after orthopedic surgeries. In this study, we determined the relationship between tourniquet time and the occurrence of pulmonary emboli in 30 patients undergoing arthroscopic knee surgeries, by using transesophageal echocardiography. The right atrium (RA) was continuously monitored by transesophageal echocardiography, and the number of emboli present was assessed with the following formula: Amount of emboli = 100 x [(total embolic area in the RA after tourniquet release) - (total area of emboli or artifact in the RA before tourniquet release)]/(RA area). ⋯ The peak amount of emboli appeared approximately 50 s after tourniquet release. In addition, there was a significant correlation between amount of emboli (Ae [%]) and tourniquet time (Ttq [min]): (Ae = 0.1 x Ttq - 1.0, r = 0.795, P < 0.01). This study suggests that acute pulmonary embolism may occur within 1 min of tourniquet release and that the number of emboli is dependent on Ttq.