Comparison of General and Local Anesthesia for Deep Brain Stimulator Insertion: A Systematic Review.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN-DBS) has become a standard treatment for many patients with Parkinson's disease (PD). The reported clinical outcome measures for procedures done under general anesthesia (GA) compared to traditional local anesthetic (LA) technique are quite heterogeneous and difficult to compare. The aim of this systematic review and metaanalysis was to determine whether the clinical outcome after STN-DBS insertion under GA is comparable to that under LA in patients with Parkinson's disease. METHODS: The databases of Medline Embase, Cochrane library and Pubmed were searched for eligible studies (human trials, English language, published between 1946 and January of 2016). The primary outcome of this study was to assess the postoperative improvement in the symptoms, evaluated using either Unified Parkinson's Disease Rating Scale (UPDRS) scores or levodopa equivalent dosage (LEDD) requirement. RESULTS: The literature searches yielded 395 citations and six retrospective cohort studies with a sample size of 455 (194 in GA and 261 in LA) were included in the analysis. Regarding the clinical outcomes, there were no significant differences in the postoperative Unified Parkinson's disease rating scale and levodopa equivalent drug dosage between the GA and the LA groups. Similarly, the adverse events and target accuracy were also comparable between the groups. CONCLUSIONS: This systematic review and meta-analysis shows that currently there is no good quality data to suggest equivalence of GA to LA during STN-DBS insertion in patients with PD, with some factors trending towards LA. There is a need for a prospective randomized control trial to validate our results.

Intracarotid Etomidate Decreases the Interhemispheric Synchronization in Electroencephalogram (EEG) During the Wada Test.

BACKGROUND: The Wada test is a diagnostic method to anesthetize 1 cerebral hemisphere and assess the language and memory functions of awake contralateral hemisphere before temporal lobectomy in patients with epilepsy. The effects of an ipsilateral injection of etomidate on the functional properties of contralateral hemisphere are not known. Our aim was to characterize the electroencephalographic (EEG) effects after intracarotid injection of etomidate and to determine the changes in synchronization between the ipsilateral and contralateral hemispheres. MATERIALS AND METHODS: We retrospectively analyzed EEG data from 15 patients who underwent Wada test with etomidate. Continuous EEG data from 4 electrodes (2 anterior [F3, F4] and 2 posterior [P3, P4]) were analyzed. After artifact rejection, we measured the amplitudes of delta (1 to 4 Hz) and alpha (7 to 13 Hz) waves and the changes in the interhemispheric synchronization before, during, and after etomidate injection. RESULTS: Ipsilateral injection of etomidate causes EEG changes in both hemispheres with increased amplitude of delta waves anteriorly and the alpha waves posteriorly. However this effect of etomidate is not uniform. Although there was a decrease in the interhemispheric synchronization of delta waves, there was no change in the synchronization of the alpha waves. CONCLUSIONS: Our study showed that the EEG effects of intracarotid ipsilateral injection of etomidate is not uniform in both hemispheres. Decrease in the interhemispheric synchronization of delta waves might serve as an indicator of ipsilateral effect of etomidate on the brain. Additional studies are needed to confirm our findings.

Neutrophil Lymphocyte Ratio as a predictor of systemic inflammation - A cross-sectional study in a pre-admission setting.

BACKGROUND: Neutrophil:lymphocyte ratio (NLR)  is an emerging biomarker that is used to predict postoperative mortality and morbidity in cardiac and cancer surgeries. The association of this biomarker with systemic illness and its usefulness in risk assessment of preoperative patients has not been fully elucidated. OBJECTIVES: To determine the prevalence of elevated NLR in preoperative patients and to examine the relationship between elevated NLR and the presence of systemic illnesses as well as anaesthesia risk indices such as American Society of Anesthesia (ASA) and the revised cardiac risk index (RCRI) scores.   DESIGN: Cross-sectional study Setting: Anaesthesia pre-admission clinic, Toronto Western Hospital, Toronto, Canada Patients: We evaluated 1117 pre-operative patients seen at an anesthesia preadmission clinic. RESULTS: NLR was elevated (>3.3) in 26.6% of target population. In multivariate analysis, congestive cardiac failure, diabetes mellitus and malignancy were independent risk factors predicting raised NLR. After regression analysis, a relationship between NLR and ASA score (Odds Ratio 1.78; 95% CI: 1.42-2.24) and revised cardiac risk index (RCRI, odds ratio 1.33; 95% CI: 1.09-1.64, p-value: 0.0063) was observed. CONCLUSIONS:  NLR was elevated (> 3.3) in 26.6% of patients. Congestive cardiac failure and malignancy were two constant predictors of elevated NLR at >3.3 and > 4.5. There was a strong association between NLR and anesthesia risk scoring tools of ASA and RCRI.

Effect of superficial cervical plexus block on postoperative quality of recovery after anterior cervical discectomy and fusion: a randomized controlled trial.

PURPOSE: Spine surgeries are increasingly being performed as a day or short-stay surgery programs. Peripheral nerve block provide site-specific pain relief with few side effects, thereby reducing surgical stress and enhancing quality of recovery. The aim of our study was to determine the effect of a superficial cervical plexus block (SCPB) on postoperative quality of recovery and analgesia in patients undergoing elective anterior cervical discectomy and fusion (ACDF). METHODS: After Research Ethics Board approval, we enrolled adults (> 18 yr) scheduled for elective single- or two-level ACDF in this randomized double-blind clinical trial. Participants were randomized to receive either a SCPB (0.25% bupivacaine, 10 mL) or No Block. The primary outcome measure was the quality of recovery at 24 hr, measured using the 40-item quality of recovery questionnaire (QoR-40). In addition, comparisons between groups were also made for postoperative opioid consumption and discharge times. RESULTS: Forty-six patients were randomized to receive either a SCPB block (n = 23) or No Block (n = 23). Median [interquartile range] aggregated global QoR-40 scores at 24 hr were significantly greater in the SCPB group, indicating good quality of recovery compared with the No Block group (179 [116-195] vs 157 [97-196], respectively; median difference, 22; 95% confidence interval [CI], 7 to 34; P = 0.002]. There were no differences between the SCPB and the No Block group with regard to mean (standard deviation) postoperative opioid consumption at 24 hr [22.9 (13.6) mg vs 24.6 (9.5) mg, respectively; mean difference 1.7; 95% CI, -5.2 to 8.7; P = 0.620] and the number of patients discharged within 24 hr (15 vs 12, respectively; P = 0.550). CONCLUSION: We showed that preoperative SCPB is an effective strategy for improving the early quality of recovery in patients undergoing single- or two-level ACDF. Nevertheless, there was no impact on opioid consumption or discharge times. This trial was registered at www.clinicaltrials.gov (NCT01662219).

Cerebrovascular reactivity to carbon dioxide under anesthesia: a qualitative systematic review.

INTRODUCTION: Controlling the arterial carbon dioxide tension (PaCO2) to reduce the cerebral blood flow (CBF) and the intracranial pressure is a common practice in neuroanesthesia. A change in CBF in response to change in PaCO2 is termed as cerebrovascular reactivity to carbon dioxide (CVR-CO2). Studies have shown that, both inhalational and intravenous anesthetic agents have variable effects on CVR-CO2 and the effect of anesthetic agents on CVR also varies with many physiological and pathologic conditions. The objectives of this review were to evaluate the effect of anesthetic agents on the CVR-CO2 in adults and to determine how this response is modified by other physiological and pathologic factors. METHODS: We conducted a systematic search of the databases of Medline, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews using related term components for both CVR-CO2 and anesthesia. Our primary outcome of this review was to determine whether the CVR-CO2 is maintained under anesthesia. The other endpoints of this review are to determine the effect of other factors (age, sex, medical comorbidities, and cerebrovascular pathology) on the CVR-CO2 under anesthesia. Because of the methodological heterogeneity in the primary studies, quantitative analysis of the data was not possible, and therefore, we have summarized the data qualitatively. RESULTS: Our search strategy yielded 1356 citations. After excluding nonpertinent papers, 38 studies were included for the systematic review. Nineteen randomized controlled trials and 19 observational studies met inclusion criteria and a total of 793 patients were studied. Transcranial Doppler was the most commonly used method for measuring CBF and changing the respiratory rate and/or minute ventilation were the most commonly used method to change the CO2 tension. CVR-CO2 is maintained with both inhalational and intravenous anesthetic agents within the range of concentrations used in clinical anesthesia. At doses leading to a broadly equivalent depth of anesthesia, the reactivity value was highest with isoflurane and the least with propofol. Individual agents differ in their degree of reactivity to hypercapnic and hypocapnic stimuli. CVR-CO2 is impaired in elderly patients when compared with young patients with both sevoflurane and propofol anesthesia. In patients with medical comorbidities, the CVR-CO2 impairment under anesthesia was associated with the severity of the underlying diseases and not the anesthetic agents. CONCLUSIONS: Our systematic review showed that within the clinical anesthesia concentrations, CVR-CO2 is maintained under both propofol and inhalational agents. However, most of the information available is from non-neurosurgical patients and these studies also suffer from significant methodological heterogeneity. Therefore, we were limited by the amount and the quality of data available for this review.

Comparison of propofol and volatile agents for maintenance of anesthesia during elective craniotomy procedures: systematic review and meta-analysis.

BACKGROUND: Both propofol and volatile anesthetics are commonly used for maintenance of anesthesia in patients undergoing neurosurgical procedures. The effects of these two classes of drugs on cerebral hemodynamics have been compared in many clinical trials The objectives of this review were to evaluate the cerebral hemodynamic effects, operative conditions, recovery profiles, postoperative complications, and neurological outcomes of propofol-based vs volatile-based anesthesia for craniotomy. METHODS: MEDLINE®, EMBASE™, Cochrane, and other relevant databases were searched for randomized controlled trials that compared propofol-maintained anesthesia with volatile-maintained anesthesia in adult patients undergoing elective craniotomy. The primary outcome measure was the intraoperative brain relaxation score. Secondary outcome measures included intraoperative cerebral hemodynamics (intracranial pressure [ICP], cerebral perfusion pressure [CPP]), cardiovascular changes, recovery profiles, postoperative complications, and clinical outcomes (neurological morbidity, mortality, quality of life). A meta-analysis was conducted using a random effects model to compare the outcomes of the two anesthetic techniques. RESULTS: Fourteen studies (1,819 patients) met inclusion criteria and were analyzed. Brain relaxation scores were similar between the two groups after dural opening; however, ICP was lower (weighted mean difference of -5.2 mmHg; 95% confidence interval -6.81 to -3.6) and CPP was higher (weighted mean difference of 16.3 mmHg; 95% confidence interval 12.2 to 20.46) in patients receiving propofol-maintained anesthesia. Postoperative complications and recovery profiles were similar between the two groups, except for postoperative nausea and vomiting being less frequent with propofol-maintained anesthesia. There were inadequate data to perform a meta-analysis on clinical outcome. CONCLUSION: Propofol-maintained and volatile-maintained anesthesia were associated with similar brain relaxation scores, although mean ICP values were lower and CPP values higher with propofol-maintained anesthesia. There are inadequate data to compare clinically significant outcomes such as neurological morbidity or mortality.