Perioperative effects of various anesthetic adjuvants with TIVA guided by bispectral index

Background

This prospective, randomized, double blinded, controlled study was designed to compare effects of intravenous co-administration of clonidine, magnesium, or ketamine on anesthetic consumption, intraoperative hemodynamics, postoperative analgesia and recovery indices during Bispectral Index (BIS) guided total intravenous anesthesia (TIVA).

Methods

After ethical committee approval and written informed consent, 120 adult patients ASA I and II scheduled for open cholecystectomy were randomly assigned to one of 4 equal groups. Group CL received clonidine 3 µg/kg and maintained by 2 µg/kg/h. Group MG received magnesium sulphate 50 mg/kg and maintained by 8 mg/kg/h. Group KET received racemic ketamine 0.4 mg/kg and maintained by 0.2 mg/kg/h. Control group (CT) received the same volume of isotonic saline. Anesthesia was induced and maintained by fentanyl, propofol and rocuronium. Propofol infusion was adjusted to keep the BIS value between 45-55. Intraoperative hemodynamics, induction time, anesthetic consumption, recovery indices, and PACU discharge were recorded.

Results

Induction time, propofol requirements for induction and maintenance of anesthesia, intraoperative fentanyl and hemodynamic values were significantly lower with Groups CL and MG compared to Groups KET and CT (P < 0.05). Patients in Group MG showed significantly lower muscle relaxant consumption, delayed recovery and PACU discharge than other groups (P < 0.05). First, analgesic requirement was significantly longer and total postoperative analgesic consumption was significantly lower in the adjuvant groups versus Group CT (P < 0.05).

Conclusions

Clonidine, magnesium, and ketamine can be useful adjuvant agents to BIS-guided TIVA. Pharmacokinetic studies of such drug combinations were recommended to investigate their interaction.

In vivo effects of different anesthetic agents on apoptosis

Background

This study was designed to measure in vivo effects of propofol, isoflurane and sevoflurane on apoptosis by measuring caspase-3 and tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) blood level as apoptotic markers.

Methods

After obtaining ethical committee approval and informed written consents, sixty adult patients ASA I scheduled for open cholecystectomy participated in this study. They were randomally allocated into one of three equal groups to receive propofol infusion, low-flow isoflurane or sevoflurane for maintenance of anesthesia. Venous blood samples were collected preoperatively, immediately postoperative and after 24 hours to measure hemoglobin, hematocrit, creatinine, liver enzymes, serum TRAIL and caspase-3 levels.

Results

There was no significant difference in hematological markers and serum creatinine. Liver enzymes showed significant postoperative rise (P < 0.05). In Propofol group, TRAIL and caspase-3 levels were significantly elevated immediately postoperative then decreased significantly after 24-hours (P < 0.05). In Isoflurane group, immediate postoperative level of TRAIL was significantly higher than 24 hours reading and significantly lower than its level in Propofol group at the same timing meanwhile caspase-3 levels were comparable at different timings. In Sevoflurane group, TRAIL and caspase-3 levels increased significantly in both postoperative samples than preoperative level and than those of Isoflurane and Propofol groups after 24 hours concerning TRAIL (P & 0.05).

Conclusions

This study concluded that isoflurane is superior and sevoflurane is the least effective among the three anesthetics in protection against apoptosis. This study neither proved nor excluded propofol-induced apoptosis. Further studies are required during lengthy procedure and in compromised patients.

A non opioid fast track anesthetic regimen for colonic resection

Fast-tracking implies a preoperative patient care paradigm that reduces time to recovery and discharge. The current study adopted fast-track anesthetic techniques, comparing outcome of a multimodal non-opioid and another opioid regimen, on recovery profiles after colonic surgery, with standard anesthetic practice. Seventy five ASA II colectomy patients were randomly assigned to one of three groups. Control group for conventional general anesthetic technique and two fast-track anesthesia groups using combined light general anesthesia and epidural techniques. Epidural maintenance was by infusion cocktail of bupivacaine-fentanyl in opioid-based group, while in non-opioid group by bupivacaine-ketamine which were both continued postoperatively for pain in lower doses and concentrations. Postoperative analgesia in control group was achieved by morphine. Supplemental ketorolac and acetaminophen were added only to non-opioid group. Early and intermediate recovery profiles were compared among the three groups together with recorded side effects. All patients in fast-track groups had significant shorter times to: awakening, extubation, orientation, both PACU arrival and discharge, hospital stay with a significant lower mean VAS for pain at rest, and rescue analgesia, compared to control group. Control group had a significant higher rate of postoperative nausea & vomiting, drowsiness and pruritus. Non-opioid fast-track regimen had a significant shorter PACU and hospital stay with lower side-effects rate than opioid one. Fast-track anesthesia enhanced recovery profile. Non-opioid regimen was superior to opioid-based, having a better recovery profile and a lower rate of side-effects.

Hepatocellular integrity during sevoflurane anesthesia with induced hypotension

The effect of sevoflurane anesthesia with or without induced hypotension on hepatocellular integrity was studied. Forty adult consented patients scheduled for various urological procedures were allocated randomly to either NTG group (nitroglycerin-induced hypotension) or a control group of twenty patients each. Anesthesia was induced and maintained by fentanyl, sevoflurane & vecuronium in both groups. In NTG group, nitro-glycerin infusion was adjusted to maintain mean arterial pressure (MAP) of 50-65 mm Hg. Specific and sensitive hepatic biomarkers; alpha (alpha) and pi (pi) glutathione S-transferases (GST) and hyaluronic acid (HA), also traditional liver enzymes; aspartate (AST) and alanine (ALT) aminotransferases were measured at: TO (pre-induction), T1, T2, T3 (15, 30 & 60 minutes after MAP stabilization respectively) and T4 (24 hours after anesthesia end). Plasma alpha-GST significantly increased at T3 in control group (p < 0.05) and in NTG group (p < 0.01) compared to TO in same group. In NTG group, hyaluronic acid con-centrations was significantly increased at T1, T2 (p < 0.05) and T3 (p < 0.01) from T0. Compared to control group, alpha- GST & HA concentrations showed significant increases in NTG group at T3 with p < 0.05 then returned back to normal range at T4. But, pi-GST, AST and ALT showed no significant changes throughout the study in both groups.

Effects of different dose regimens of magnesium on pharmacodynamics and anesthetic requirements of balanced general anesthesia

The present double- blind, randomized, placebo-controlled study was designed to assess the effect of two different dose regimens of magnesium sulphate (MgSO4) administration on intraoperative propofol and vecuronium requirements and postoperative fentanyl consumption in patients undergoing hernioraphy. Sixty patients were allocated to three equal groups; two magnesium groups and control group. Magnesium groups received 50 mg kg(-1) of magnesium preoperatively followed by intravenous infusion of magnesium 8 mg kg(-1) h(-1) (Mg1 G) or 16 mg kg(-1) h(-1) (Mg2 G). Patients in control group received the same volume of isotonic solution. Anesthesia was induced and maintained with propofol, fentanyl, and vecuronium. Magnesium Gs required significantly lower propofol (121.0 +/- 4.5, 117.4 +/- 6.3 microg kg(-1) min. (-1) in Mg1 & Mg2 Gs respectively vs. 153.8 +/- 8.4 microg kg(-1) min. (-1) in control G), and vecuronium requirements (0.097 +/- 0.008, 0.0921 +/- 0.006 mg kg(-1) h(-1) in Mg1 & Mg2 Gs respectively vs. 0.124 +/- 0.01 mg kg(-1) h(-1) in control G). Magnesium significantly shortened the onset time of vecuronium (154.0 +/- 25.9, 162.0 +/- 22.4 sec. in Mg1 & Mg2 Gs respectively vs. 227.4 +/- 10.9 sec. in control), prolonged its clinical duration (44.7 +/- 3.2, 46.4 +/- 5.1 min. in Mg1 & Mg2 Gs respectively vs. 26.0 +/- 3.9 min. in control) and prolonged its recovery index which was significantly longest in Mg2 G (25.4 +/- 1.9 min.) compared to Mg1 G (20.1 +/- 2.1 min.) and control (15.3 +/- 1.4 min.). Fentanyl consumption on the first postoperative day was significantly higher in control (1.52 +/- 0.08 microg kg(-1)) than in magnesium Gs (0.96 +/- 0.07, 0.91 +/- 0.08 microg kg(-1) in Mg1 & Mg2 Gs respectively). Postoperative sedation score showed significantly the highest value in Mg2 G compared to Mg1 and control Gs. Mean arterial blood pressure and heart rate were lower in magnesium groups with lowest value in Mg2 G. It is concluded that magnesium 50 mg kg(-1) bolus followed by 8 mg kg(-1) h(-1) leads to significant reductions in intraoperative propofol and vecuronium and postoperative fentanyl consumption. Doubling magnesium infusion rate added minimal benefits on the expense of haemodynamic consequences and delayed recovery.

Role of cholinesterase activity on pharmacodynamics of mivacurium preceded by pancuronium in elderly and young adults

Mivacurium- pancuronium combination proved to be more potent than either drug given alone. The goal of this study was to evaluate the safety and efficacy of this combination in elderly group and its correlation to plasma butyryl cholinesterase (Bche) activity. Forty patients, ASA I or II scheduled for elective open cholecystectomy were allocated into two groups of twenty patients each: young group (18- 55 years) and elderly group (60-75 years). Anesthesia was induced with midazolam, fentanyl, and propofol then maintained with isoflurane and opioid supplementation. Neuromuscular blockade (NMB) was monitored by train-of-four (TOF) stimulation of the ulnar nerve. After calibration, NMB was achieved by 16 microg kg(-1) pancuronium followed by 32 microg kg(-1) mivacurium. The following parameters were recorded: The onset time, clinical duration, recovery index and the total dose of mivacurium and pancuronium together with hemodynamic data. Three blood samples for Bche activity were collected: before pancuronium injection, 3 min. and 30 min. afterwards in both groups. The onset time and the recovery index of NMB were comparable in both groups. The duration of action was significantly prolonged in elderly group (49.8 +/- 10.48 min.) compared to young one (37.13 +/- 7.81 min.). The total dose of mivacurium was significantly less in the elderly group (22.56 +/- 2.39 microg kg(-1) hr(-1)) when compared to the young group (25.78 +/- 3.05 microg kg(-1) hr(-1)). For all patients, the preoperative Bche activity was within the normal range. After pancuronium injecttion, it showed a significant reduction in both groups at three and thirty minutes except a non significant value in young at thirty minutes. This reduction showed a significantly higher percent change in the elderly group (30.37 +/- 22.01) than the young group (8.60 +/- 19.19) at thirty minutes. There were significant intra operative variations in the percent changes of hemodynamic data compared to the preoperative values, yet, still within the clinically acceptable range. So, the use of a small dose of pancuronium followed by a small dose of mivacurium with a ratio of 1:2 can produce synergism without affecting either the recovery profile of mivacurium or the clinical hemodynamic stability even in the elderly group.