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.

Comparison of two topographical airway length measurements in adults.

BACKGROUND: A correct estimate of the tracheal tube insertion depth can prevent complications, including endobronchial intubation and vocal cord trauma. We evaluated a new topographical method for endotracheal tube positioning relative to the carina, using a well-known prior topographical method for comparison. METHODS: One hundred adult (male 50, female 50) patients were studied. The comparison topographic length (in cm) was measured by adding the distance between the right mouth corner and the right mandibular angle to the distance between the right mandibular angle and the center of the sternal manubrium. The new endotracheal tube insertion depth (in cm) was determined by adding the distance between the right mouth corner and the vocal cords, measured with the endotracheal tube itself, to the distance between the thyroid prominence and the manubriosternal joint, and then subtracting 4 cm. After intubation, the endotracheal tube was positioned properly at the right mouth corner and the endotracheal tube tip was evaluated using a fiberoptic bronchoscope at the carina. RESULTS: The distances from the tip of the endotracheal tube to the carina were not significantly different between the methods in the same gender. However, our method allowed endotracheal tube tip placement between 3 cm and 5 cm, above the carina more frequently than the prior method in males. CONCLUSIONS: The new topographical method can be used as a guide to positioning the endotracheal tubes.

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.

Effects of the tourniquet deflation on bispectral index during knee arthroscopic surgery under the general anesthesia.

BACKGROUND: Tourniquet deflation during lower extremity surgery affects the hemodynamics and metabolism of the patient, which can affect brain activity. This study examined the changes in brain activity during tourniquet deflation by measuring the bispectral index (BIS). METHODS: The BIS was measured during surgery in forty patients who had received knee arthroscopic surgery under general anaesthesia. The BIS was measured 5 minutes before deflation (DB5) and 5 minutes after deflation (DA5). RESULTS: The BIS at DB5 and DA5 was 50.2 +/- 9.9 and 44.4 +/- 10.4, respectively. The BIS of DA5 was significantly lower than that of DB5 (P < 0.05). CONCLUSIONS: Tourniquet deflation during lower extremity surgery decreases the BIS associated with hemodynamic and metabolic changes. However, its clinical significance in neurologically critical patients, such as geriatric or neurologically disabled patients, remains to be clarified.