Effect of beach chair position on bispectral index values during arthroscopic shoulder surgery.

BACKGROUND: Bispectral index (BIS) monitoring reduces the cases of intraoperative awareness. Several factors can alter BIS readings without affecting the depth of anesthesia. We conducted a study to assess the impact of beach chair position (sitting position) on BIS readings. METHODS: General anesthesia was administered to 30 patients undergoing arthroscopic shoulder surgery. Patients were kept in neutral position (supine) for 10 minutes and BIS readings, mean arterial blood pressure, heart rate, end-tidal carbon dioxide, and end-tidal sevoflurane were recorded. Patients were then shifted to beach chair position. After 15 minutes, data were recorded. RESULTS: A significant decrease in BIS values (P < 0.01) associated with a position change from neutral position to beach chair position was evident. CONCLUSIONS: BIS values are significantly decreased in the beach chair position compared with the neutral position and might affect interpretation of the depth of anesthesia.

An estimation of right- and left-sided central venous catheter insertion depth using measurement of surface landmarks along the course of central veins.

BACKGROUND: In this study we sought to determine whether the topographical measurement along the course of the central veins can estimate the approximate insertion depths of central venous catheters (CVC). METHODS: Two hundred central venous catheterizations were performed via the right and left internal jugular vein (IJV) or subclavian vein (SCV). The anterior approach, using the sternocleidomastoid muscle as a landmark, was used for IJV catheterization and the infraclavicular approach for SCV. Topographical measurement was performed by placing the catheter with its own curvature over the draped skin starting from the insertion point of the needle through the ipsilateral clavicular notch, and to the insertion point of the second right costal cartilage to the manubriosternal joint. The CVC was inserted and secured to a depth determined topographically. The distance between the CVC tip and the carina and the angle of the left-sided CVC tip to the vertical were measured on the postoperative chest radiograph. RESULTS: The mean (SD) tip position of 50 CVCs placed via the right IJV was 0.1 (1.1) cm above the carina; right SCV, 0.0 (0.9) cm; left IJV, 0.3 (1.0) cm above the carina, and left SCV, 0.2 (0.9) cm below the carina. CVC locations could be predicted with a margin of error between 2.2 cm below the carina and 2.3 cm above the carina in 95% of patients. There were steeper (≥ 40°) angles to the vertical in the left-sided CVCs whose tips were above the carina (17 out of 54) than below the carina (2 out of 46). CONCLUSIONS: The approximate insertion depth of a CVC can be estimated using measurement of surface landmarks along the pathway of central veins.

Effects of esomeprazole premedication on gastric pH during laparoscopic surgery.

BACKGROUND: The use of CO2 for pneumoperitoneum during laparoscopic surgery provokes a decrement in the gastric pH. Since the incidence rate of PONV increases after laparoscopic surgery, the possibility of lung aspiration of gastric juice with a low pH during a postanesthetic emergence may increase and this could be fatal for the patient. We conducted this study to determine the effects of esomeprazole premedication on inhibiting the decrement of the gastric pH during laparoscopic surgery. METHODS: 40 adult patients with no underlying diseases were chosen and 20 patients each were grouped as C (the control group) and E (the esomeprazole group). In both group, 0.2 mg glycopyrrolate was given intramuscularly 30 minutes prior to the surgery. In group E, esomeprazole was given orally 2 hours prior to the surgery. The pH, PaCO2, and PETCO2 were measured via pH probe, an ABGA and an capnogram at preinsufflation and 15, 30 and 60 minutes after the CO2 insufflation and right before CO2 exhaustion (predeflation). RESULTS: Comparing the measurements of the gastric pH between group E and group C, all the results showed a significant increase in group E (P < 0.05). The difference of the PaCO2 and PETCO2 in the two groups was not significance. CONCLUSIONS: In contrast to the decrease in the gastric pH as the PaCO2 and PETCO2 increased in group C, the gastric pH in group E remained high until the end of the surgery despite the increase in the PaCO2 and PETCO2. Esomeprazole premedication seem to have an effect for inhibiting the gastric pH decrement regardless of the increase in the PaCO2 and PETCO2 during laparoscopic surgery.