Comparison of Dexmedetomidine Versus Fentanyl-Based Anesthetic Protocols Under Patient State Index Guidance in Patients Undergoing Elective Neurosurgical Procedures with Intraoperative Neurophysiological Monitoring.

Objectives The study was designed to elucidate the effects of dexmedetomidine as an anesthetic adjunct to propofol in total intravenous anesthesia (TIVA) on anesthetic dose reduction, the quality of intraoperative neurophysiological monitoring (IONM) recordings, analgesic requirements, and recovery parameters in patients undergoing neurosurgical procedures with neurophysiological monitoring. Methods A total of 54 patients for elective neurosurgical procedures with IONM were randomized to group D (dexmedetomidine) and group F (fentanyl). A loading dose of the study drug of 1µg/kg followed by 0.5 µg/kg/h infusion was used in two groups. Propofol-based TIVA with a Schneider target-controlled infusion model was used for induction and maintenance with effect site concentration of 4-5 and 2.5-4 µg/mL, respectively, titrated to a Patient State Index (PSI) of 25-40. Baseline IONM recordings were obtained after induction. The mean propofol consumption, number of patient movements, quality of IONM recordings, number of fentanyl boluses, hemodynamic characteristics, and recovery parameters were recorded. Results The mean propofol consumption was significantly lower in group D when compared to group F (101.4 ± 13.5 µg/kg/min vs 148.0 ± 29.8 µg/kg/min). Baseline IONM recordings were acquired in all patients without any difficulty. The two groups were comparable with respect to the number of additional boluses of fentanyl, patient movements, and recovery characteristics. Conclusion Dexmedetomidine as an adjuvant to propofol in TIVA reduces the requirement of the latter, without affecting the IONM recordings. The addition of dexmedetomidine also ensures stable hemodynamics and decreases the requirement of opioids with similar recovery characteristics.

Comparison of two techniques of goal directed fluid therapy in elective neurosurgical patients - a randomized controlled study.

BACKGROUND: Goal directed fluid therapy (GDFT) may be a rational approach to adopt in neurosurgical patients, in whom intravascular volume optimization is of utmost importance. Most of the parameters used to guide GDFT are derived invasively. We postulated that the total volume of intraoperative intravenous fluid administered during elective craniotomy for supratentorial brain tumours would be comparable between two groups receiving GDFT guided either by the non-invasively derived plethysmography variability index (PVI) or by stroke volume variation (SVV). METHODS: 60 ASA category 1, 2 and 3 patients between 18 and 70 years of age were randomized to receive intraoperative fluid guided either by SVV (SVV group; n = 31) or PVI (PVI group; n = 29). The total volume of fluid administered intraoperatively was recorded. Serum creatinine was measured before the surgery, at the end of the surgery, 24 h after surgery and on the fifth post-operative day. Arterial cannulation was performed before induction in all patients. Serum lactate was measured before induction, once in 2 h intraoperatively, at the end of the surgery and 24 h after the surgery. Brain relaxation score was assessed by the surgeon during dural opening and dural closure. Patients were followed up till discharge or death. The duration of mechanical ventilation and the duration of hospital stay was noted for all patients. RESULTS: The volume of fluid given intraoperatively was significantly higher in the SVV group (p = 0.005). The two groups were comparable with respect to serum lactate and serum creatinine measured at pre-determined time intervals. Brain relaxation score was also comparable between the groups. SVV and PVI displayed moderate to strong correlation intraoperatively. The duration of mechanical ventilation and the length of the hospital stay were comparable between the two groups. CONCLUSIONS: PVI and SVV are equally effective in guiding GDFT in adults undergoing elective craniotomy for supratentorial brain tumours.

Clinical utility of ultrasonography, pulse oximetry and arterial line derived hemodynamic parameters for predicting post-induction hypotension in patients undergoing elective craniotomy for excision of brain tumors - A prospective observational study.

Background: Hypotension, which is a common adverse effect of induction of anesthesia, may be especially detrimental in neurosurgical patients. Hence, it is important to investigate hemodynamic parameters which may be useful in identifying patients at risk of hypotension, following induction. Our study was designed to assess the utility of parameters derived from ultrasonography, pulse oximeter and arterial line for predicting post-induction hypotension. Methods: The study was designed as a prospective, observational trial. Written informed consent was obtained from 100 American Society of Anesthesiologists (ASA) 1 and 2 patients, between 18-60 years of age, scheduled for elective craniotomy for brain tumors. Arterial cannula was inserted before induction of anesthesia and connected to Vigileo cardiac output monitor. Baseline stroke volume variation (SVV), stroke volume (SV), cardiac index (Ci), cardiac output (CO) and pulse pressure variation (PPV) were recorded. Plethysmography variability index (PVI) and perfusion index (PI) were obtained from the Masimo rainbow SET® Radical-7® pulse oximeter. Ultrasonographic assessment of the inferior vena cava (IVC) was performed before induction of anesthesia and again within 15 min after induction. Maximum and minimum IVC diameters (dIVCmax and dIVCmin) and collapsibility index (CI) were measured. All the other aforementioned parameters were recorded every minute starting at induction, until the 15th minute following induction. Results: PI, CI and dIVCmax were found to have the largest AUCROC for the prediction of post-induction hypotension (AUCROC 0.852, 0.823 and 0.781 respectively). Multiple logistic regression analysis revealed CI to be the most significant independent factor for the prediction of post-induction hypotension. Conclusion: Non-invasively derived hemodynamic parameters like dIVCmax, CI and PI were more accurate for the prediction of post-induction hypotension, compared to invasively derived parameters.

Effect of General Anesthetics on Caspase-3 Levels in Patients With Aneurysmal Subarachnoid Hemorrhage: A Preliminary Study.

BACKGROUND: General anesthesia has been associated with neuronal apoptosis and activation of caspases. Apoptosis is a crucial factor in early brain injury following aneurysmal subarachnoid hemorrhage (aSAH). We conducted a double-blind, prospective, randomized pilot study to evaluate the effect of 4 anesthetic agents on cerebrospinal fluid (CSF) and serum caspase-3 levels in aSAH patients. MATERIALS AND METHODS: A total of 44 good-grade aSAH patients with preoperative lumbar drain scheduled for surgical clipping or endovascular coiling were randomized to receive maintenance of anesthesia with propofol, isoflurane, sevoflurane, or desflurane. Caspase-3 levels were measured in CSF and serum samples collected at baseline, 1 hour after induction, and 1 hour after cessation of anesthesia. RESULTS: Compared with baseline, there was a decrease in CSF caspase-3 levels and an increase in serum caspase-3 levels 1 hour after exposure to all 4 anesthetic agents; levels returned to baseline values after cessation of anesthesia. Median CSF caspase-3 levels at baseline, 1 hour after anesthesia exposure, and 1 hour after cessation of anesthesia were 0.0679, 0.0004, and 0.0689 ng/mL, respectively (P<0.05). Median serum caspase-3 levels at baseline, 1 hour after anesthesia exposure, and 1-hour after cessation of anesthesia were 0.0028, 0.0682, and 0.0044 ng/mL, respectively (P<0.05). CONCLUSIONS: Propofol, isoflurane, sevoflurane, or desflurane have similar effects on CSF and serum caspase-3. The reduction of intraoperative CSF caspase-3 levels suggests a possible role for general anesthesia in neuroresuscitation by slowing the neuronal apoptotic pathway.

Pre-emptive multimodal analgesic regimen reduces post-operative epidural demand boluses in traumatic shaft of femur fracture - A randomised controlled trial.

BACKGROUND AND AIMS: The efficacy of preemptive multimodal analgesia in post-traumatic patients has not been elucidated. Our aim was to evaluate the efficacy of preemptive MMA regimen in reducing the epidural demand boluses in the first 48 hours following the traumatic shaft of femur fractures. METHODS: Patients scheduled for traumatic femur fracture surgery were randomised (n = 135) into two groups in this double blind, placebo controlled trial. Patients received either (Preemptive multimodal group) intravenous acetaminophen 1 gm, diclofenac 75 mg, morphine 3 mg, 75 mg Pregabalin (per oral) or a placebo 30 minutes pre-operatively. Intra-operatively, all patients were managed with spinal and epidural anaesthesia. Post-operatively, patients received patient-controlled epidural analgesia (PCEA) programmed to deliver a bolus of 5 ml of 0.2% Ropivacaine with 2 µg/ml of Fentanyl with lockout interval time of 15 min. Primary outcome was number of PCEA boluses received post-operatively over 48 h. Secondary outcomes measures were time to receive first epidural bolus, postoperative VAS scores and episodes of post-operative nausea, vomiting and sedation. Total number of PCEA bolus doses over 48 hours and VAS scores were analysed using Mann-Whitney test. RESULTS: Significant reduction in median number of demand boluses were observed in preemptive multimodal group (3 [2-4]) compared to placebo group (5 [4-7]); P = 0.00. Time to first rescue epidural bolus was significantly greater in preemptive multimodal group than placebo group. CONCLUSION: The use of preemptive MMA regimen reduced the requirement of demand epidural bolus doses.