Acta anaesthesiologica Taiwanica : official journal of the Taiwan Society of Anesthesiologists最新文献

Pregnancy can be rarely complicated with cerebral angioma. Such patients can pose a problem to the anesthesiologist and can present for caesarean section (CS). The main anesthetic challenge is prevention of rupture of angioma and subsequent bleed due to intraoperative surge of blood pressure. Both general anesthesia and regional anesthesia have been used in such patients. Spinal anesthesia has the advantage of safety, less hypertensive surge, and better analgesia as well as less blood loss. We hereby present successful anesthetic management of such a case presented for emergency CS done under spinal anesthesia.

Objectives

Dexmedetomidine, an α2 agonist, has been evaluated for its hypnotic, analgesic, and anxiolytic properties in the intraoperative period and critical care setting. However, data on the effect of dexmedetomidine on attenuation of pressor response to direct laryngoscopy and tracheal intubation are limited. We studied the effect of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg on hemodynamic responses to tracheal intubation, and dose requirements of anesthetics for induction and their adverse effects.

Methods

Eighty adult patients scheduled for elective surgery under general anesthesia requiring tracheal intubation were included. Patients were randomized into two groups: dexmedetomidine and placebo (n = 40 each). The study drug was administered intravenously over a period of 10 minutes prior to induction. Direct laryngoscopy and endotracheal intubation were performed. Hemodynamic parameters, the total dose of propofol, and adverse effects were recorded during induction and postintubation periods for 15 minutes.

Results

The maximum percentage increase in the heart rate after intubation was 19.6% less in the dexmedetomidine group than that in the placebo group (12.96% vs. 32.57%). The maximum percentage increases in systolic blood pressure, diastolic blood pressure, and mean blood pressure after intubation were significantly lower in the dexmedetomidine group than in the placebo group (12.38% vs. 45.63%, 19.36% vs. 60.36%, and 15.34% vs. 50.33%, respectively). There was a significant reduction of the mean total dose of propofol required for induction, 1.04 mg/kg in the dexmedetomidine group versus 2.01 mg/kg in the placebo group (p < 0.001). No serious side effects or adverse reactions were observed in either group.

Conclusion

Administration of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg resulted in significant attenuation of the rise in the heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure, until 5 minutes postintubation. It significantly reduced the dose requirements of propofol for induction and caused minimal side effects.

Objective

Endoscopic retrograde cholangiopancreatography (ERCP) is a procedure used for diagnostic and therapeutic purposes. Most of the patients may feel pain, anxiety, and discomfort during this procedure, so conscious sedation is usually used during ERCP. General anesthesia would be considered if conscious sedation fails to achieve the requirement of the endoscopists. Several studies showed that propofol-based sedation could provide a better recovery profile. However, propofol has a narrow therapeutic window and complications may occur beyond this window. The present study aimed to find out the complications and the associated risk factors during ERCP procedure under propofol-based deep sedation.

Methods

We retrospectively reviewed data from anesthetic and procedure records of the patients who underwent ERCP under propofol-based deep sedation from January 2006 to July 2010 at Far Eastern Memorial Hospital, Taipei, Taiwan. All propofol-based deep sedations were conducted by anesthesiologists. The incidence of complications was determined and the independent risk factors identified by the multivariable logistic regression model.

Result

Propofol-based deep sedation was provided for 552 patients who received ERCP procedure. The majority of the patients were male, the mean age was 60 ± 16 years and American Society of Anesthesiologists physical status II–III. Almost 30% of patients experienced hypotension during the procedure, although no mortality or morbidity was associated with this complication. Sex, age, anesthetic time, American Society of Anesthesiologists status, hypertension, and arrhythmia were significantly different (p < 0.05) between patients with hypotension and without hypotension during the procedure. Multivariable logistic regression identified sex and age to be the independent predictors of hypotension.

Conclusion

Hypotension was the most frequent anesthetic complication during procedure under propofol-based deep sedation, but this method was safe and effective under appropriate monitoring. Age is the strongest predictor of hypotension and therefore propofol-based deep sedation should be conducted with caution in the elderly.

Objective

Transversus abdominis plane (TAP) block is a recently introduced regional anesthesia technique that is used for postoperative pain reduction in some abdominal surgeries. The present study evaluated the efficacy of the TAP block on the post laparoscopic cholecystectomy pain intensity and analgesic consumption.

Methods

Fifty-four patients were enrolled in three groups: TAP block with normal saline (Group 1, n = 18); TAP block with bupivacaine (Group 2, n = 18); and TAP block with bupivacaine plus sufentanil (Group 3, n = 18). The time to the first fentanyl request, fentanyl consumption in the 24 hours following surgery, and postoperative pain intensity at 30 minutes, 1 hour, 6 hours, 12 hours, and 24 hours following discharge for recovery were measured and recorded.

Results

The total amount of 24-hour fentanyl consumption was higher in Group 1 (877.8 ± 338.8 μg) than either Group 2 (566.7 ± 367.8 μg) or Group 3 (555.5 ± 356.8 μg; p = 0.03). Postoperative pain score was higher in Group 1 than intervention groups (p = 0.006); however, there was no significant difference in intervention groups. The time to the first fentanyl request in Group 1 (79.44 ± 42.2) was significantly lower than Group 3 (206.38 ± 112.7; p = 0.001).

Conclusion

The present study demonstrated that bilateral TAP block with 0.5% bupivacaine reduces post laparoscopic cholecystectomy pain intensity and fentanyl request and prolongs time to the first analgesic request. Adding sufentanil to the block solution reduced neither pain intensity nor fentanyl further consumption.

Drug interaction is fundamental in performing anesthesia. A response surface model (RSM) is a very useful tool for investigating drug interactions. The methodology appeared many decades ago, but did not receive attention in the field of anesthesia until the 1990s. Drug investigations typically start with pharmacokinetics, but it is the effects on the body clinical anesthesiologists really care about. Typically, drug interactions are divided into additive, synergistic, or infra-additive. Traditional isobolographic analysis or concentration-effect curve shifts are limited to a single endpoint. Response surface holds the complete package of isobolograms and concentration effect curves in one equation for a given endpoint, e.g., loss of response to laryngoscopy. As a pharmacodynamic tool, RSM helps anesthesiologists guide their drug therapy by navigating the surface. We reviewed the most commonly used models: (1) the Greco model; (2) Reduced Greco model; (3) Minto model; and (4) the Hierarchy models. Each one has its unique concept and strengths. These models served as groundwork for researchers to modify the formula to fit their drug of interest. RSM usually work with two drugs, but three-drug models can be constructed at the expense of greatly increasing the complexity. A wide range of clinical applications are made possible with the help of pharmacokinetic simulation. Pharmacokinetic-pharmcodynamic modeling using the RSMs gives anesthesiologists the versatility to work with precision and safe drug interactions. Currently, RSMs have been used for predicting patient responses, estimating wake up time, pinpointing the optimal drug concentration, guide therapy with respect to patient's well-being, and aid in procedures that require rapid patient arousal such as awake craniotomy or Stagnara wake-up test. There is no other model that is universally better than the others. Researches are encouraged to find the best fitting model for different occasions with an objective measure.

Limiting the intracuff pressure of a laryngeal mask airway (LMA) to <60 cmH₂O is recommended in clinical practice. This report aimed to assess the efficacy of a modified syringe technique to adjust the intracuff pressure of an LMA. In a preclinical study, commercially available 20-mL syringes were attached to the pilot balloon of LMAs with different preset intracuff pressures (40 cmH₂O, 50 cmH₂O, 60 cmH₂O, 70 cmH₂O, 80 cmH₂O, 100 cmH₂O, and 120 cmH₂O). After attachment, the syringe plunger was allowed to passively rebound. If no rebound of the plunger was observed after attachment, 1 mL of air was withdrawn and the plunger was allowed to passively rebound again. This technique allowed the plunger to overcome static friction and avoid excessive deflation of the LMA cuffs. The intracuff pressure was measured using a manometer after the plunger ceased moving. In the preclinical study, the intracuff pressure was always less than or close to 60 cmH₂O after adjustment using this modified syringe technique. After evaluating the performance and characteristics of the syringe in the preclinical study, we concluded that the modified syringe technique may be useful for adjusting LMA intracuff pressure effectively.