Macintosh laryngoscope vs. Pentax-AWS video laryngoscope: comparison of efficacy and cardiovascular responses to tracheal intubation in major burn patients.

BACKGROUND: Patients with major burns accompanied with airway edema need more attention for airway management. Although the Pentax-AWS has an advantage in managing endotracheal intubation more easily, its usefulness cannot be assured if it does not maintain hemodynamic stability in burn patients. The aim of this study was to compare cardiovascular responses and general efficacy of the Pentax-AWS and Macintosh laryngoscopes in burn patients. METHODS: American Society of Anesthesiologists physical status 2 or 3 adult patients with major burn injury were randomly assigned to group P (AWS, n = 50) or group M (Macintosh, n = 50). Fifty-nine patients assigned to the Macintosh group and no patient to AWS group were excluded because of failure to first intubation. Hemodynamic data at baseline, just before and after intubation as well as 3, 5 and 10 minutes after intubation and grade of sore throat were recorded in two groups. Intubation time, success rate of intubation, number of intubation attempts and the percentage of glottic opening (POGO) scores were also observed and analyzed in all patients. RESULTS: A statistically significant increase in heart rate just after laryngoscopy was seen in group M. The success rate of the first attempt in group P (100%) was greater than with the group M (46%). POGO scores were higher in group P (97 ± 4%) than in group M (48 ± 29%) CONCLUSIONS: The use of Pentax-AWS offers a reduced degree of heart rate elevation compared with the Macintosh laryngoscope and better intubation environments in major burn patients.

The BIS and hemodynamic changes in major burn patients according to a slow infusion of propofol for induction.

BACKGROUND: Many pathophysiologic alterations in patients with major burns can cause changes in the response of propofol. The aim of this study is to determine the appropriate induction dose of propofol using a slow infusion rate for major burn patients to obtain desirable sedation and hypnotic conditions with minimal hemodynamic changes. METHODS: 45 adults with major burns and who were electively scheduled for escharectomy less than a week after injury were recruited. For induction with propofol, the patients were randomly allocated to one of two groups (group 1: 1.5 mg/kg, n = 20 and group 2: 2.0 mg/kg, n = 25). The infusion rate was 20 mg/kg/hr. The systolic and diastolic blood pressure (SBP, DBP), the heart rate, the bispectral index and the modified observers' assessment of the alertness/sedation scale (OAA/S) were measured before the induction and after the propofol infusion, as well as immediately, 3 and 5 minutes after intubation. RESULTS: The SBP and DBP were significantly decreased after the propofol infusion in both group, but there were no significant differences between the two groups. The BIS values after the propofol infusion and intubation were 44.2 ± 16.1 and 43.5 ± 13.8 in group 1, and 45.6 ± 10.3 and 46.5 ± 11.4 in group 2, respectively, and there were no differences between the 2 groups. CONCLUSIONS: When propofol is administrated to major burn patients, an induction dose of 1.5 mg/kg is appropriate and a slow infusion rate of 20 mg/kg/hr is safe for maintaining the desired hypnotic conditions and this dose and rate cause no significant hemodynamic problems.

Cardiovascular crisis after small dose local infiltration of epinephrine in patient with asymptomatic subarachnoid hemorrhage -A case report-.

The infiltration of dilute epinephrine solution has been used for many years to provide hemostasis. However, epinephrine has adverse cardiovascular effects, such as arrhythmia, pulmonary edema, and even cardiac arrest. We have experienced epinephrine-induced cardiovascular crisis, with severe hypertension, tachycardia, and cardiac arrest after subcutaneous infiltration of a 2% lidocaine and 1 : 200,000 epinephrine solution in a patient with an asymptomatic subarachnoid hemorrhage. We provided successfully advanced cardiac life support in the operating room and cardioverted the patient back into a sinus rhythm with no untoward effects. The patient recovered without any apparent sequelae after intensive care.

Remifentanil for postoperative patient-controlled analgesia after laparoscopic-assisted vaginal hysterectomy: dose-finding study.

BACKGROUND: This randomized, double-blinded clinical study was designed to compare the efficacy and safety of three regimens of intravenous (IV) patient-controlled analgesia (PCA) with remifentanil for postoperative analgesia after laparoscopic-assisted vaginal hysterectomy during the first 24 postoperative hours. METHODS: Thirty-four patients were randomly allocated into three groups. The first group received IV remifentanil PCA at a basal rate of 0.02 microgram/kg/min, a bolus of 0.3 microgram/kg, and a lockout time of 15 min. The second group received IV-PCA at a basal rate of 0.025 microgram/kg/min, a bolus of 0.375 microgram/kg, and a lockout time of 15 min. The third group received IV-PCA at a basal rate of 0.03 microgram/kg/min, a bolus of 0.45 microgram/kg, and a lockout time of 15 min. Age, weight, height, and duration of surgery and anesthesia were recorded. Heart rate, systolic and diastolic blood pressure (BP) and oxygen saturation by pulse oxymetry were recorded in the recovery room as a base line after the operation. Heart rate, systolic and diastolic BP, sedation score, visual analogue scale (VAS), and postoperative nausea and vomiting (PONV) scores were recorded at 1 h, 3 h, 6 h, 12 h, and 24 h after the initiation of IV-PCA. RESULTS: Thirty two patients were evaluated. The VAS in group 1 at 1, 3 and 6 hours after surgery was significantly higher than in other groups (P < 0.05). There were no clinically relevant differences between the groups in PONV, sedation scores, or hemodynamic parameters. CONCLUSIONS: This study suggests that IV remifentanil PCA with at a basal rate of 0.025 microgramram/kg/min (group 2) provided efficacious analgesia after laparoscopic-assisted vaginal hysterectomy. Special attention must be given to respiratory depression during establishment of PCA with remifentanil.

Tracheal intubation without the use of muscle relaxant in severe burn patients using propofol and varying doses of remifentanil.

BACKGROUND: Severe burn patients often have a difficult airway. Tracheal intubation can be conducted safely in patients in a stable hemodynamic condition using a propofol in conjunction with remifentanil without employing muscle relaxant. However, no studies have been conducted to date to evaluate intubation of severe burn patients. Therefore, this study was conducted to evaluate the condition of tracheal intubation with propofol and varying doses of remifentanil without muscle relaxants in severe burn patients. METHODS: Eighty severe burn patients were divided into four groups at random. Anesthesia was intravenously induced by continuous infusion of propofol (4 microgram/ml of effect site concentration)and slowly injected remifentanil. Groups 1, 2, 3, and 4 received 1, 1.5, 2, and 2.5 microgram/kg of remifentanil, respectively. Ninety seconds after the administration of remifentanil, tracheal intubation was attempted. We used a scoring system in which jaw relaxation, the state when laryngoscopy was inserted, vocal cord opening, cough, limb movement, and difficulty with laryngoscopy were divided into < or = 2 (acceptable) or > or = 3 (not acceptable). In addition, the hemodynamic changes were measured at baseline, before intubation, and 1, 2, 3, 4, and 5 min after intubation. RESULTS: Clinically acceptable intubating conditions were observed in 35%, 40%, 55%, and 70% of the patients in groups 1-4, respectively. The mean arterial pressure and heart rate decreased immediately before intubation in all groups. One patient was treated for bradycardia however, no patients manifested hypotension. CONCLUSIONS: Propofol and slowly injected remifentanil (2.5 microgram/kg) without muscle relaxant can provide clinically acceptable intubating conditions and stable hemodynamic conditions in major burn patients. However, further studies should be conducted to evaluate the effects of increased doses of remifentanil.

Prediction of difficult intubation in patients with postburn sternomental contractures: modified onah class.

BACKGROUND: Postburn sternomental contractures cause various changes in mouth, oral cavity, pharynx, larynx and related structures. Although there are many methods to predict difficult intubation, the modified Mallampati test (mMT) and the El-Ganzouri multivariate risk index (EGRI) are popular tests. The authors wanted to compare modified Onah class with these 2 tests and also explored the possibility that Onah class could be an adequate independent predictor for difficult intubation. METHODS: One hundred and nine patients, aged 18 to 60 years of age, scheduled for elective surgery for reconstruction of postburn sternomental contractures were divided according to the modified Onah class. We made assessments prior to general anesthesia with respect to mouth opening, thyromental distance, mMT, neck movement, ability to prognath, body weight, and history of difficult tracheal intubation. The accuracy, specificity, positive and negative predictive values were calculated from the data of the 3 tests, and as the 3 tests were compared with patient's laryngoscopic view grade according to Cormack and Lehane criteria by using the Chi-square test. RESULTS: The incidence of Cormack and Lehane grade III, IV was 39.4%. Onah class showed significantly higher accuracy, specificity, and positive predictive value than mMT and EGRI. There were significant correlations between modified Onah class 2b, 3 and the Cormack and Lehane grade III, IV. CONCLUSIONS: Application of modified Onah class for preoperative prediction of the degree of difficulty with laryngeal visualization can reduce the frequency of both an unanticipated failure to visualize laryngeal structures as well as potential unnecessary interventions related to over-prediction of airway difficulty in patients with postburn sternomental contractures.