Levobupivacaine versus racemic bupivacaine for extradural anesthesia for cesarean delivery.

BACKGROUND AND OBJECTIVES: Bupivacaine is available as a racemic mixture of dextrobupivacaine and levobupivacaine. Many studies show that dextrobupivacaine has a greater inherent central nervous system and cardiovascular toxicity than levobupivacaine. The aim of the present study was to investigate the clinical efficacy and safety of levobupivacaine compared with racemic bupivacaine for extradural anesthesia. METERIAL AND METHOD: The authors studied 61 patients undergoing elective cesarean delivery who received either 0.5% levobupivacaine (n = 31) or 0.5% bupivacaine (n = 30) extradurally, in a randomized, double blind study. RESULTS: The 2 groups were similar in terms of time to block suitable for surgery, duration of sensory block, time to T10 regression, time to onset and offset of motor block, verbal numeric pain scores at abdominal opening and at child birth. Mean (SD) dose of 0.5% levobupivacaine and 0.5% bupivacaine were 19.3 (4.6) ml and 17.3 (3.8) ml respectively, p = 0.069. CONCLUSION: Levobupivacaine produces an extradural block that is similar to bupivacaine, and is an alternative to bupivacaine for cesarean delivery patients.

Depth of endotracheal tubes in Thai adult patients.

OBJECTIVE: To predict the proper depth of placement of endotracheal tubes, oral and nasal. MATERIAL AND METHOD: This was a prospective study of 100 patients who underwent general anesthesia with oral endotracheal intubation. The cuff of the endotracheal tube was placed 2 cm below the vocal cords. The positions of the endotracheal tube tip and the airway distances of the patients were measured by fiberoptic bronchoscope; OC = the distance from the right upper canine to the vocal cords, NC = the distance from the right external naris to the vocal cords and T = the distance from the vocal cords to the carina. The correlation between the airway distances and patient's factors were analyzed. The proper depth of placement of the endotracheal tube was calculated with the formula OTT = OC + T-2, nasal endotracheal tube NTT = NC + T-2. RESULTS: The mean distance from the endotracheal tube tip to the carina was 3.0 +/- 1.48 cm (ranged 0.7 - 7.5 cm). The distance from the endotracheal tube tip to the carina of 86 from 100 patients was more than 2 cm. The mean OC was 9.79 +/- 1.27 cm. The mean NC was 15.00 +/- 0.84 cm. The mean T were 13.03 +/- 1.48 cm in males and 11.63 +/- 1.25 cm in females and it also related to the height of the person (Pearson correlation = 0.557, p value < 0.05). These distances did not relate to gender. CONCLUSION: The predicted formula of the depth of the endotracheal tube as "Chula formula"; OTT = 4 + (Ht/10) cm (The distance from the right upper canine to the point which is 2 cm above the carina) NTT = 9 + (Ht/10) cm (The distance from the right external naris to the point which is 2 cm above the carina).