Radha Arunkumar

Non-invasive anesthesia for children undergoing proton radiation therapy

BACKGROUND Proton therapy is a newer modality of radiotherapy during which anesthesiologists face specific challenges related to the setup and duration of treatment sessions. PURPOSE Describe our anesthesia practice for children treated in a standalone proton therapy center, and report on complications encountered during anesthesia. MATERIALS AND METHODS A retrospective review of anesthetic records for patients ⩽18years of age treated with proton therapy at our institution between January 2006 and April 2013 was performed. RESULTS A total of 9328 anesthetics were administered to 340 children with a median age of 3.6years (range, 0.4-14.2). The median daily anesthesia time was 47min (range, 15-79). The average time between start of anesthesia to the start of radiotherapy was 7.2min (range, 1-83min). All patients received Total Intravenous Anesthesia (TIVA) with spontaneous ventilation, with 96.7% receiving supplemental oxygen by non-invasive methods. None required daily endotracheal intubation. Two episodes of bradycardia, and one episode each of; seizure, laryngospasm and bronchospasm were identified for a cumulative incidence of 0.05%. CONCLUSIONS In this large series of children undergoing proton therapy at a freestanding center, TIVA without daily endotracheal intubation provided a safe, efficient, and less invasive option of anesthetic care.

Anaesthetic techniques for unique cancer surgery procedures

Recent advances in cancer therapy have seen increased combinations of different treatment modalities as well as novel approaches that affect anaesthetic care. Increasingly, surgery is being combined with chemotherapy and radiation therapy. Moreover, minimally invasive procedures are gaining popularity and more targeted therapies are being used. These events have created a demand for new anaesthetic techniques from anaesthesiologists in order to provide safe patient care. This article will discuss anaesthetic considerations for proton therapy, hyperthermic intracavitary chemotherapy, limb perfusion, radiosurgery, robotic surgery and intra-operative radiation therapy and high-dose brachytherapy.

Enhanced recovery after surgery for oncological craniotomies

Enhanced recovery after surgery (ERAS) initiatives in the fields of gastrointestinal and pelvic surgery have contributed to improved postoperative functional status for patients and decreased length of stay. A similar comprehensive protocol is lacking for patients undergoing craniotomy for tumor resection. A literature search was performed using PubMed. These references were reviewed with a preference for recent high quality studies. Cohort and retrospective studies were also included if higher levels of evidence were lacking. A literature search was conducted for scalp blocks and minimally invasive craniotomies. Papers were scored using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria for evidence level and recommendation grade. Seventeen ERAS items were reviewed and recommendations made. The current body of evidence is insufficient to create a standardized protocol for craniotomy and tumor resection. However, this initial review of the literature supports pursuing future research initiatives that explore modalities to improve functional recovery and decrease length of stay in craniotomy patients.

Preoperative statin use is not associated with improvement in survival after glioblastoma surgery

Cohort studies have suggested that the use of statins is associated with decreased risk of glioma formation and mortality. Here, a cohort of patients with glioblastoma multiforme (GBM) was analyzed to further investigate associations between preoperative use of statins and recurrence, and progression free and overall survival. Patients who had surgery for GBM (N=284) were followed up for a median of 18.1months. Seventy-eight patients were taking statins preoperatively while the rest were not. Cox proportional hazards models adjusted for several covariates of interest were applied before and after propensity score matching. Compared with statin users, those not taking the lipid-lowering drugs had similar progression free survival before (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.70-1.26; p=0.68) and after propensity score matching (HR 0.95, 95% CI 0.67-1.35; p=0.68). Mortality was similar between both groups of patients before (HR 0.94, 95% CI 0.70-1.22; p= 0.73) and after propensity score matching (HR 1.13, 95% CI 0.78-1.64; p=0.49). Age and dexamethasone use were independent prognostic factors of survival. Contrary to previously published evidence, this study could not find an association between preoperative statin use and longer survival in GBM patients. Due to the small number of patients and retrospective nature of the study, further work is needed to understand the role of perioperative statins in GBM patients.

Association Between Perioperative Hyperglycemia and Survival in Patients With Glioblastoma.

Background: Several studies have examined the association between hyperglycemia in the first 10 to 12 weeks following surgery and postoperative survival in glioblastoma multiforme (GBM) patients. We hypothesize that episodes of hyperglycemia before, during and/or following surgery for primary GBM are independent predictors of disease progression and mortality. Materials and Methods: A total of 162 adult patients were included in the analysis. All patients received adjuvant temozolamide. The progression free survival (PFS) and overall survival (OS) rates at 1 and 5 years were analyzed using different glycemic cutoff values. Multivariate analyses were conducted to test the association between preoperative, intraoperative and postoperative hyperglycemia with PFS and OS. Results: Kaplan-Meier curves revealed a trend toward increased PFS and OS with lower glucose concentrations with the exception of glucose concentrations >180 mg/dL in the intraoperative/postoperative day 0 time period. Univariate analysis of blood glucose levels did not demonstrate a statistically significant effect on PFS in any time period, however hyperglycemia was statistically significant for OS in the preoperative time period. Although, multivariate analysis showed no statistically significant association with hyperglycemia on PFS, a statistically significant decrease in OS was seen for plasma glucose concentrations >112 mg/dL (P=0.01) and >180 mg/dL (P=0.01) in the preoperative period. There was a decreasing effect on OS with blood glucose concentrations greater than the median in multiple time periods (P=0.02). Conclusions: Preoperative hyperglycemia is associated with poor OS after GBM surgery.

The use of isoflurane and desflurane as inhalational agents for glioblastoma surgery. A survival analysis.

BACKGROUND Several studies have examined the impact of anesthetics on cancer recurrence. Isoflurane but not desflurane has protumoral effects. We hypothesize the use of isoflurane but not desflurane during surgery for primary GBM is an independent predictor of disease progression and mortality. METHODS 378 adult patients were included in the study. The progression free survival (PFS) and overall survival (OS) rates at 1 and 5years were compared in patients who had either desflurane or isoflurane alone or in combination with propofol infusion. Multivariate analyses were conducted to test the association between preoperative, intraoperative and postoperative hyperglycemia with PFS and OS. RESULTS Kaplan-Meier curves demonstrated similar survival in patients who had either desflurane or isoflurane. The use of a propofol infusion during surgery did not affect survival. Univariate analysis demonstrated that age, body mass index and the adjusted Charlson comorbidity score were associated with reduced survival. The multivariate analysis confirmed that age and BMI but not the type volatile anesthetic use were independent prognostic factors for PFS (HR, 95%CI: 1.07, 0.85-1.37, 9=0.531) and OS (HR, 95%CI: 1.13, 0.86-1.48, p=0.531). CONCLUSION The use of isoflurane or desflurane during GBM surgery is not associated with reduced PFS or OS.

A multi-institutional pilot survey of anesthesia practices during proton radiation therapy

BACKGROUND AND PURPOSE Physicians responsible for anesthesia and/or sedation (A/S) at emerging proton radiation therapy centers (PTCs) seek information about practices at established centers. We conducted a survey of A/S practices at established PTCs to provide this information for physicians at new PTCs. METHODS AND MATERIALS A web-based survey was sent to physicians responsible for A/S at 37 established PTCs. Questions were based on practice patterns and the preferred method of A/S delivery during proton-radiation therapy. One representative per institution was surveyed. RESULTS A response rate of 38%, with a combined case load of more than 15,000 anesthetics per year was obtained. Children younger than 4 years old often (72%) required A/S. The most favored A/S techniques involved total intravenous anesthesia with propofol and an unprotected airway (57%) or general anesthesia with sevoflurane and a laryngeal mask airway (36%). It was notable that 21% of facilities did not have dedicated recovery rooms. Also, anesthesia gas evacuation outlets were absent at 43% of treatment rooms. CONCLUSIONS A/S is commonly delivered to patients undergoing proton radiation therapy, most often with total intravenous anesthesia. To avert potential obstacles to the safe delivery of care, anesthesiologists at emerging centers are encouraged to participate throughout the design and planning phases of new PTCs.

Intraoperative serum lactate is not a predictor of survival after glioblastoma surgery

BACKGROUND Cancer cells can produce lactate in high concentrations. Two previous studies examined the clinical relevance of serum lactate as a biomarker in patients with brain tumors. Patients with high-grade tumors have higher serum concentrations of lactate than those with low-grade tumors. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB). METHODS This was a retrospective study. Demographic, lactate concentrations and imaging data from 275 adult patients with primary GB was included in the analysis. The progression free survival (PFS) and overall survival (OS) rates were compared in patients who had above and below the median concentrations of lactate. We also investigated the correlation between lactate concentrations and tumor volume. Multivariate analyses were conducted to test the association lactate, tumor volume and demographic variables with PFS and OS. RESULTS The median serum concentration of lactate was 2.3mmol/L. A weak correlation was found between lactate concentrations and tumor volume. Kaplan-Meier curves demonstrated similar survival in patients with higher or lower than 2.3mmol/L of lactate. The multivariate analysis indicated that the intraoperative levels of lactate were not independently associated with changes in survival. On another hand, a preoperative T1 volume was an independent predictor PFS (HR 95%CI: 1.41, 1.02-1.82, p=0.006) and OS (HR 95%CI: 1.47, 1.11-1.96, p=0.006). CONCLUSION This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery. To date, there are no clinically available serum biomarkers to determine prognosis in patients with high-grade gliomas. These tumors may produce high levels of lactic acid. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB). In this study, we collected perioperative and survival data from 275 adult patients with primary high-grade gliomas to determine whether intraoperative serum acid lactic concentrations can serve as a marker of prognosis. The median serum concentration of lactate was 2.3mmol/L. Our analysis indicated the intraoperative levels of lactate were not independently associated with changes in survival. This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery.

Fasting Guidelines: Do They Need to Be Different?

The purpose of fasting guidelines is to reduce the incidence of aspiration during induction and maintenance of anesthesia. Although the traditional dogma of ‘nothing by mouth for 8 hours’ has been accepted for years, there is a lack of scientific evidence in support of this practice. Furthermore, preoperative fasting has been shown to be associated with some unintended unfavorable metabolic and psychological consequences. As a result, patients may be better served if fasting guidelines were approached from a patient and/or procedure specific perspective. Differences in fasting recommendations may therefore have to be accepted as the norm, rather than an exception.

Preoperative assessment: General principles

The number of diagnostic and interventional procedures performed outside the operating room (OR) has increased dramatically over the last several years. There are multiple challenges involved in anesthesia provided to patients outside the OR. With improvements in technology for interventional procedures outside the OR, older, younger and sicker patients who may be inoperable are scheduled for these procedures. Appropriate preoperative assessment and optimization of medical status are important aspects of our practice. Safe patient care can be enhanced by adequate patient assessment in the preoperative period, appropriate patient selection and use of targeted interventions to improve outcomes.