Hoarseness is a common complication after tracheal intubation and prolonged hoarseness may be very limiting for a patient. This study was designed to examine the duration of hoarseness after tracheal intubation and to identify risk factors that may increase the duration of hoarseness. We prospectively studied 3093 adult patients (aged 18–77 yr), over a 3 yr period who required tracheal intubation. Postoperative hoarseness was assessed on the day of operation and on postoperative days 1, 3, and 7 by standardized interview by the resident anaesthetist managing the patient. If postoperative hoarseness was still present on postoperative day 7, the patient was followed up until complete resolution. We evaluated age, gender, weight, Cormack grades, duration of intubation, and the anaesthetic agents used as factors affecting the duration of hoarseness after tracheal intubation. Hoarseness was observed in 49% of patients on the day of surgery and in 29%, 11%, and 0.8% on 1, 3, and 7 postoperative days, respectively. Multiple regression analysis showed that patient age and duration of intubation, but not gender, weight, Cormack grades, or the agents used, were significant predictors of increased duration of hoarseness after tracheal intubation. We found three patients with arytenoid cartilage dislocation (0.097%) in our study population. The age of the patient and duration of intubation were significant factors in the duration of hoarseness after tracheal intubation. In addition, the incidence of arytenoid cartilage dislocation was 0.097%.

The authors investigated myocardial epinephrine sensitization by subanesthetic concentrations of halothane. The dose-response relationship for the action of halothane was examined with etomidate plus varying subanesthetic concentrations of halothane in dogs. The arrhythmogenic threshold of epinephrine was decreased in a dose-dependent manner at end-tidal concentrations of halothane between 0.1 and 0.3%. At end-tidal halothane is greater than 0.3%, and no further reduction of arrhythmogenic threshold of epinephrine occurred. The plasma concentrations of epinephrine producing four or more premature ventricular contractions in 15 s were 201.3 +/- 34.3, 98.1 +/- 13.9, 60.3 +/- 8.63, 57.9 +/- 12.8, 54.5 +/- 8.61, and 53.9 +/- 4.86 ng/ml (mean +/- SEM), at 0, 0.1, 0.3, 0.5, 1.0, and 1.5% of halothane at end-tidal concentrations, respectively. The results suggest that in the presence of etomidate, halothane produces myocardial sensitization to epinephrine at subanesthetic concentrations as low as 0.1%. Increasing halothane to 0.3% produces a further reduction in the arrhythmogenic dose of epinephrine.

Objectives: It has been reported that the effect of intrathecally administered α2 adrenergic receptor (α2 AR) agonists is enhanced in mice that are chronically tolerant to systemic morphine. However, contributory factors have not been identified. Here we examined whether repeated systemic morphine affected the analgesic potency of intrathecal dexmedetomidine and the expression of subtype A, B and C α2 AR (α2A, α2B and α2C AR) in the dorsal root ganglion and dorsal horn in mice.Methods: After subcutaneous injection of morphine or saline for two weeks, dexmedetomidine was administered intrathecally to evaluate its antinociceptive effect. Also, the α2 AR subtypes and µ-opioid receptor mRNA expression in lumbar dorsal root ganglion was quantified using PCR, and α2A and α2C AR in lumbar dorsal root ganglion and dorsal horn were examined by immunohistochemistry.Key findings: Daily morphine enhanced the antinociceptive effect of intrathecal dexmedetomidine, increased all the α2 AR subtypes but decreased the µ-opioid receptor mRNA expression in dorsal root ganglion and increased immunoreactivity of α2A and α2C AR in dorsal root ganglion and dorsal horn.Conclusions: These results suggest that systemic daily morphine enhances the analgesic effect of intrathecal dexmedetomidine via up-regulation of the α2A, α2B and α2C AR in lumbar dorsal root ganglion and dorsal horn.

Background: Arytenoid cartilage dislocation/subluxation is one of the rare complications following tracheal intubation, and there have been no reports about risk factors leading this complication. From our clinical experience, we have an impression that patients undergoing cardiovascular operations tend to be associated with this complication. Aims: We designed a large retrospective study to reveal the incidence and risk factors predicting the occurrence and to examine whether our impression is true. Settings and Designs: This was a retrospective study. Methods: We retrospectively studied 19,437 adult patients who were intubated by an anesthesiologist in our operation theater from 2002 to 2008. The tracheal intubation was performed by a resident anesthesiologist managing the patients. Only patients whose postoperative voice was disturbed more than 7 days were referred to the Department of Otorhinolaryngology-Head and Neck Surgery and examined using laryngostroboscopy by a laryngologist to diagnose arytenoid cartilage dislocation/subluxation. We evaluated age, sex, weight, height, duration of intubation, difficult intubation, and major cardiovascular operation as risk factors to lead this complication. Statistical Analysis: The data were analyzed by logistic regression analysis to assess factors for arytenoid cartilage dislocation/subluxation after univariate analyses using logistic regression analysis. Results: Our analysis indicated that difficult intubation (odds ratio: 12.1, P = 0.018) and cardiovascular operation (odds ratio: 9.9, P < 0.001) were significant risk factors of arytenoid cartilage dislocation/subluxation. Conclusion: The present study demonstrated that major cardiovascular operation is one of the significant risk factors leading this complication.