Does Cerebral Monitoring Improve Ophthalmic Surgical Operating Conditions During Propofol-Induced Sedation?

Abstract

Sudden movements from over-sedation during ophthalmic surgery can be detrimental to the eye. Bispectral index (BIS) and middle-latency auditory-evoked potentials (Alaris AEP index, AAI) were reported to be accurate indicators for the level of sedation and loss of consciousness. We assessed these monitors during sedation with special emphasis on preventing over-sedation. One-hundred patients scheduled for elective eye surgery were sedated with target-controlled propofol infusion and randomly allocated to BIS-guided, AAI-guided, BIS/AAI-guided, or clinically guided groups (n = 25 each). The initial target concentration was 0.5 microg x mL(-1) in patients >70 yr and 1.0 microg x mL(-1) in all other patients. The concentration was increased every 3 min by 0.1 or 0.2 microg x mL(-1), respectively until the patient had reached a BIS value of 75 (range 70-90) or an AAI of 40 (range 35-60). The surgeon who was blinded to group allocation assessed treatment quality after the procedure. Sedation was converted into general anesthesia in four patients because of excessive head movements. BIS was out of range 7% of the time vs 58% for AAI. No significant differences in treatment quality were observed among the four groups. We conclude that propofol sedation, guided by BIS or AAI monitoring, did not enhance ophthalmic surgical operating conditions over sedation guided by clinical observation only.

Patient-controlled sedation vs. anaesthetic nurse-controlled sedation for cataract surgery in elderly patients

“…Janzen et al (8) reported that two of their 20 patients using propofol PCS showed significant head movement, probably attributable to disorientation during emergence from sedation. Oei-Lim et al (19) also reported that the sedation was converted to general anaesthesia in four of 100 patients because of their excessive head movements while using bispectral index (BIS)-guided target-controlled infusion of propofol. However, no patient in our study showed significant head movement.…”

“…The major difference might lie in the dosage of propofol used. We used a bolus demand dose of 10 mg of propofol compared with 0.25 or 0.5 mg/kg in a study of Janzen et al (8) and the total dose used was about 1 mg/kg/h compared with 2.5-2.9 mg/kg/h in a study of Oei-Lim et al (19). Pac-Soo et al (20) also studied the PCS for cataract surgery with a smaller bolus dose (3.3 mg) of propofol but when similar amounts used (about 1 mg/kg/h) as ours, satisfactory decrease of anxiety without significant complications was reported.…”

Effects of A-Line Autoregression Index (AAI) Monitoring on Recovery After Sevoflurane Anesthesia for Bariatric Surgery

“…Previous studies on the efficacy of AAI in lean subjects yielded to conflicting results. AAI monitoring failed to impact emergence from anesthesia for knee arthroscopy [12], eye surgery [13], or superficial surgery [14]. In contrast, AAI monitoring reduced volatile gas consumption and recovery times after a 2-h volatile anesthesia for gynecological laparoscopic surgery or for major abdominal surgery [7][8][9][10].…”

“…AAI, however, is not sensitive to opioids nitrous oxide or ketamine [6] so that AAI indexes better a hypnotic-based anesthetic technique (i.e., low-dose analgesic plus high-dose volatile anesthetic) rather than a more analgesic-based anesthesia (i.e., remifentanil combined with low-dose hypnotic) [5,6]. In non-obese patients, AAI monitoring effectively reduced anesthetic consumption and recovery times [7][8][9][10][11], although positive findings have not been confirmed in all studies [12][13][14]. AAI may provide more consistent advantages in obese than in lean patients because of difficulty in drug dosing in the former [1][2][3][4][5].…”

Effectiveness and safety of intravenous dexmedetomidine sedation for ophthalmic surgery under regional anesthesia

“…2,4,5 On the other hand, deep sedation tapering can be challenging when dexmedetomidine is employed along with other traditional sedatives. 23 In keeping with previous studies, 17,20,24 we chose a low infusion rate of dexmedetomidine, both for the loading dose (1.2 μg/kg/h) and the maintenance dose (0.3 μg/kg/h).…”