Impact of perioperative lidocaine infusion and bis monitorization on remifentanil dosage in hypotensive anesthesia.

BACKGROUND: Combination of local and regional anesthetic agents are widely used in emergency and surgical setting and the interaction between the medications used in general anesthesia and these local and/or regional anesthetic becomes a growing concern in current patient management system. The interaction between general anesthetic agents and the local anesthetic agents given epidurally, spinally, intravenously or intramuscularly and the effects of BIS monitorisation on combined propofol-remifentanil anesthesia are examined in several studies. In literature, there is no research investigating the effect of lidocaine infusion on remifentanil and anesthetic dosage used in hypotensive anesthesia. The aim of this study is to examine this effect. PATIENTS AND METHODS: We studied 39, ASA I-II patients undergoing elective transsphenoidal endoscopic hypophyseal adenoma excision procedure. After preoperative examination and informed consent of the patient, monitorisation with non invasive blood pressure measurement, electrocardiography, pulse oxymeter and Bispectral Index (BIS) was performed. 0.9% NaCl infusion was started via a 20 G route. Lidocaine (1%) was given as 1.5 mg.kg^-1 hour-1 infusion after 1.5 mg.kg^-1 bolus dosage given in 10 minutes. Lidocaine infusion was started at the same time with anesthesia induction and was stopped after surgery. 0.9% NaCl was given as bolus dosage and as infusion in control group. Induction was maintained via propofol (1%) with 10 mg (1 ml) doses given in 5 seconds and it was applied in every 15 seconds until BIS < 45'. During maintenance of anesthesia desflurane-remifentaniloxygen (50%)-air (50%) mixture was used. Desflurane was titrated by BIS measurement between 40 and 50¹². Remifentanil infusion was started after propofol induction with 0.1 µg.kg^-1.min^-1 dosage and it was titrated between 0.1-0.5 µg.kg^-1.min^-1 levels. For intubation, rocuronium with 0.8 mg kg^-1 dosage was given during induction. After the surgical procedure, it was antagonised with neostigmine and atropine. For postoperative analgesia 1 g paracetamole was given IV after the surgery within 15 minutes and it was reapplied with 1 gr doses in every 6 hours. After extubation, the pain of the patients was examined at 15. minute at the recovery room with VRS (VRS; 0-no pain, 1-slight pain, 2-moderate pain, 3-severe pain). If VRS was greater than 2, 50 mg dolantine was given IM. For prevention of nausea and vomitting, 8 mg ondansetron was given IV. Perioperative total doses of remifentanil, desflurane (ml) (anesthesia machine records) and lidocaine (mg) were recorded after the surgery. Perioperative hemodynamic parameters (systolic, diastolic, mean blood pressures, heart rates) were recorded after monitorisation (basal), after intubation, after the start of the surgery and after extubation. RESULTS: There were no statistically significant difference between two groups with respect to patient characteristics (age, gender, weight, length, Basal Mass Index = BMI) (p > 0.05). The duration of anesthesia and surgery were also not different statistically (p > 0.05). There were no statistically significant difference between two groups with respect to remifentanil dose (p > 0.05).There were no statistically significant difference between two groups with respect to eye opening and extubation times (p > 0.05). When usage rates and amounts of dolantine, paracetamole and novalgine were compared, we found no statistically significant difference between two groups (p > 0.05). Basal mean arterial blood pressure measurements of the patients and mean arterial blood pressure measurements of the patients after induction, after intubation, 1 minute, 5 minutes, 10 minutes, 15 minutes after discharge of surgery and after extubation showed no statistically significant difference (p > 0.05). Basal heart rate measurements and the heart rates after induction, after intubation, 1 minute, 5 minutes, 10 minutes, 15 minutes after discharge of surgery and after extubation showed no statistically significant difference (p > 0.05). Basal BIS measurements and BIS measurements after induction, after intubation, 1 minute, 5 minutes, 10 minutes, 15 minutes after discharge of surgery and after extubation showed no statistically significant difference (p > 0.05). CONCLUSIONS: We found no statistically significant difference between two groups about different parameters. But new investigations with different local anesthetic agents may show sigificant difference and usage of these local anesthetic agents may be advised. [ABSTRACT FROM AUTHOR]