Bispectral index in calves anesthetized with xylazine, midazolam, ketamine, isoflurane and subjected to continuous rate infusion of lidocaine

Correlation between bispectral index value and modified Glasgow Coma Scale score in dogs with altered level of consciousness

OBJECTIVE

This study aims to identify the correlation between bispectral index (BIS) value and modified Glasgow Coma Scale (MGCS) score in dogs with altered level of consciousness (ALOC).

DESIGN

This prospective, observational, clinical study was conducted from February 2016 to March 2017, and follow-up was conducted until the death of dogs or their discharge from the hospital.

SETTING

This study was performed at the Small Animal Teaching Hospital.

ANIMALS

A total of 31 client-owned dogs (males, 20; females, 11) with ALOC and MGCS score <18 with no restrictions for age, breed, sex, and body weight were included. Dogs that received neuromuscular blocking agents before MGCS score evaluation were excluded.

INTERVENTIONS

BIS values were measured using the Covidien BIS Loc 2 Channel OEM module and a pediatric 4 sensor with a bifrontal application pattern.

MEASUREMENTS AND MAIN RESULTS

Minimal databases of initial neurological assessment, blood profiles, and chest and skull radiographs were developed. In addition, MGCS scores and BIS values were recorded. The mean BIS values for mild, moderate, and severe brain injuries were 89.14 ± 6.52, 77.21 ± 9.82, and 50.58 ± 27.04, respectively. Correlation analysis revealed a significantly positive relationship between BIS values and MGCS scores (r = 0.75; P < 0.001).

CONCLUSIONS

The significant correlation observed between MGCS scores and BIS values in dogs with ALOC demonstrated the usefulness of BIS as an alternative to MGCS for monitoring consciousness in patients with ALOC caused by traumatic brain injury, encephalitis, etc.

Effect of ketamine combined with lidocaine in pediatric anesthesia

Background

We conducted a randomized clinical trial to determine whether adjunctive lidocaine diminishes the incidence of adverse effects in pediatric patients sedated with ketamine.

Methods

This case‐control study involved 586 consecutive pediatric patients necessitating anesthesia. Then systolic blood pressure, heart rate, respiratory rate, and blood oxygen saturation were observed. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen (BUN), and creatinine (Cr) levels were tested. General dose of ketamine, the time of onset and duration of anesthesia and postoperative recovery, anesthesia effect, and adverse reaction were subsequently compared. High‐performance liquid chromatography was employed to detect ketamine concentration at different time points after administration, and the postoperative cognition function was further evaluated.

Results

Intra‐ and post‐operation, the rising degree of ALT, AST, BUN, and Cr in patients treated with ketamine was higher than those in patients treated with the ketamine‐lidocaine complex. General dose of ketamine, the time of onset and duration of anesthesia, postoperative recovery time, and the incidence rate of adverse reaction in patients treated with ketamine‐lidocaine complex were lower, but the concentration of ketamine was higher compared to the patients treated with ketamine. In patients treated with the ketamine‐lidocaine complex, elimination half‐life of ketamine was prolonged, the area under curve was increased, and the plasma clearance rate was decreased relative to those with ketamine alone.

Conclusions

Ketamine combined with lidocaine may be beneficial in shortening the onset of anesthesia, promoting postoperative awake, prolonging elimination half‐life, increasing area under curve, and decreasing plasma clearance rate and incidence of adverse reactions.

Continuous infusion of propofol in calves: bispectral index and hemodynamic effects

OBJECTIVE

To assess the bispectral index (BIS) and the hemodynamic effects of propofol administered by continuous infusion at different rates in calves.

STUDY DESIGN

Experimental crossover study.

ANIMALS

Eight intact male Dutch calves, aged 6-12 months and weighing 84-124 kg.

METHODS

The calves were anesthetized with propofol (5 mg kg(-1) ) intravenously (IV), and after endotracheal intubation, positioned in right lateral recumbency and allowed to breathe ambient air. Anesthesia was maintained by continuous infusion of propofol, administered IV with an infusion pump at 0.6 mg kg(-1)  minute(-1) (treatment G6) or 0.8 mg kg(-1)  minute(-1) IV (treatment G8), for 60 minutes. The eight animals were anesthetized twice, 1 week apart. The following hemodynamic variables and BIS were assessed before the induction of anesthesia (baseline) and 15, 30, 45, and 60 minutes after beginning the infusion of propofol: heart rate, systolic, diastolic and mean arterial pressures, cardiac output, mean pulmonary artery pressure, cardiac index, stroke index, pulmonary vascular resistance index, and systemic vascular resistance index, BIS, electromyography, and signal quality index.

RESULTS

The continuous infusions of propofol at different rates did not alter BIS variables during the infusion time between dose rates, and no clinically significant hemodynamic changes were observed.

CONCLUSIONS AND CLINICAL RELEVANCE

A continuous infusion of propofol at 0.6 or 0.8 mg kg(-1)  minute(-1) caused minimal hemodynamic changes without clinical relevance in calves. BIS could not be reliably used to discriminate the anesthetic depth during the two propofol infusion rates.