Awake craniotomy for brain tumor resection is becoming a standard of care for lesions residing within or in close proximity to regions presumed to have language or sensorimotor function. Evidence shows an improved outcome including greater extent of resection, fewer late neurological deficits, shorter hospital stay, and longer survival after awake brain tumor resection compared with surgery under general anesthesia. The surgeon's ability to maximize tumor resection within the constraint of preserving neurological function by intraoperative stimulation mapping in an awake patient is credited for this advantageous result. It is possible that the care provided by anesthesiologists, especially the avoidance of certain components of general endotracheal anesthesia, may also be important in the outcome of awake brain tumor resection. We present our interpretation of the evidence that we believe substantiates this proposition. However, due to the lack of direct evidence based on randomized-controlled trials and the heterogeneity of anesthetic techniques used for awake craniotomy, our perspective is largely speculative and hypothesis generating that needs to be validated or refuted by future quality research.

Introduction

Mentorship in medicine is associated with increased career satisfaction and personal development. Despite these benefits, little is known about mentorship in anesthesiology training programs. Our objectives were to determine (1) the prevalence of formal mentorship programs among anesthesiology training programs in Canada, (2) the prevalence of informal and formal mentorship among anesthesiology residents in Canada, and (3) the predictors of having an identified mentor among anesthesiology residents in Canada.

Methods

We conducted a cross-sectional web-based survey of residents and program directors from Canadian anesthesiology residency programs. Program directors were questioned about formal mentorship programs, and residents were asked to provide demographic data and information about their mentorship relationships. We analyzed the relationship between resident characteristics and mentorship.

Results

Our survey response rates were 76% and 39% for the Program Director Survey and the Resident Survey, respectively. Formal mentorship programs were present in 54% of residency training programs, and 94% of residents agreed that mentorship was important. Seventy-four percent of residents identified at least one mentor, although 42% of these residents did not interact regularly with their mentor. Mentors and mentees were more likely to be of the same gender. If a formal mentorship program was present, residents were more likely to identify a mentor (82 vs 17%) and interact regularly with their mentor (70 vs 46%).

Conclusions

Formal mentorship programs were present in half of anesthesiology training programs. Although 74% of the residents identified a mentor, 42% did not interact regularly with their mentor. The presence of a formal mentorship program was positively associated with mentorship.

Background

We hypothesized that the addition of dexmedetomidine in a clinically relevant dose to propofol-remifentanil anesthesia regimen does not exert an adverse effect on motor-evoked potentials (MEP) and somatosensory-evoked potentials (SSEP) in adult patients undergoing thoracic spinal cord tumor resection.

Methods

Seventy-one adult patients were randomized into three groups. Propofol group (n = 25): propofol-remifentanil regimenand the dosage was adjusted to maintain the bispectral index (BIS) between 40 and 50. DP adjusted group (n = 23): Dexmedetomidine (0.5 μg/kg loading dose infused over 10 min followed by a constant infusion of 0.5 μg/kg/h) was added to the propofol-remifentanil regimen and propofol was adjusted to maintain BIS between 40 and 50. DP unadjusted group (n = 23): Dexmedetomidine (administer as DP adjusted group) was added to the propofol-remifentanil regimen and propofol was not adjusted. All patients received MEP, SSEP and BIS monitoring.

Results

There were no significant changes in the amplitude and latency of MEP and SSEP among different groups (P > 0.05). The estimated propofol plasma concentration in DP adjusted group (2.7 ± 0.3 μg/ml) was significantly lower than in propofol group (3.1 ± 0.2 μg/ml) and DP unadjusted group (3.1 ± 0.2 μg/ml) (P = 0.000). BIS in DP unadjusted group (35 ± 5) was significantly lower than in propofol group (44 ± 3) (P = 0.000).

Conclusions

The addition of dexmedetomidine to propofol-remifentanil regimen does not exert an adverse effect on MEP and SSEP monitoring in adult patients undergoing thoracic spinal cord tumor resection.

Trial registration

The study was registered with the Chinese Clinical Trial Registry on January 31st, 2014. The reference number was ChiCTR-TRC-14004229.

Cerebral ischemia is the pathophysiological condition in which the oxygenated cerebral blood flow is less than what is needed to meet cerebral metabolic demand. It is one of the most debilitating complications in the perioperative period and has serious clinical sequelae. The monitoring and prevention of intraoperative cerebral ischemia are crucial because an anesthetized patient in the operating room cannot be neurologically assessed. In this paper, we provide an overview of the definition, etiology, risk factors, and prevention of cerebral ischemia during surgery.

Purpose

Perioperative stroke is associated with significant morbidity and mortality yet patients may not be aware of their risk or receive appropriate counselling. Our objectives were to 1) compare patient's perceived vs calculated risk of stroke; 2) determine level of worry; and 3) assess prior discussion about perioperative stroke risk amongst elective patients undergoing non-cardiac, non-neurologic surgery.

Methods

Over a consecutive four-week period, surveys were distributed at two pre-anesthetic clinics to adult patients scheduled for non-cardiac, non-neurologic surgery. The survey included questions about demographics, perioperative stroke risk factors, patient perception of their quantitative and qualitative stroke risk, level of worry about stroke, and risk discussions. We identified independent predictors of risk underestimation amongst medium- and high-risk patients.

Results

Six hundred patients completed the survey (response rate 78%). Of these, 479, 104, and 15 patients were classified as low-, medium-, and high-risk, respectively (with two patients missing this data point). Most medium- (86%) and high-risk (80%) patients did not identify their elevated risk. Amongst medium- and high-risk patients, independent predictors of risk underestimation were lower education and absence of kidney disease. Medium- and high-risk patients were more worried than low-risk patients about perioperative stroke (median [interquartile range] visual analogue scale score 2 [0.5-4] vs 1 [0-2], P = 0.001). Fewer than half of patients had discussed perioperative stroke previously (40%, 23%, and 12% of high-, medium-, and low-risk patients, respectively).

Conclusions

Patients at higher risk of stroke frequently underestimate their risk of perioperative stroke. The majority of patients had not discussed perioperative stroke prior to anesthetic consultation.

Background

Midazolam has been found to exacerbate or unmask limb motor dysfunction in patients with brain tumors. This study aimed to determine whether the exacerbated upper limb motor-sensory deficits are mediated through benzodiazepine sites by demonstrating reversibility by flumazenil in patients with gliomas in eloquent areas.

Methods

This was an interventional, parallel assignment, nonrandomized trial. Study subjects were admitted in the operating room. Patients with supratentorial eloquent area gliomas and volunteers of similar age without neurologic disease were sedated with midazolam, but still responsive and cooperative. Motor and sensory functions for upper extremities were evaluated by the Nine-Hole Peg Test before and after midazolam, as well as after flumazenil reversal.

Results

Thirty-two cases were included: 15 in the glioma group and 17 in the control group. The total dose of midazolam and flumazenil were comparable between the groups. In the glioma group, the times to task completion after midazolam in the contralateral hand (P = 0.001) and ipsilateral hand (P = 0.002) were 26.5 (95% CI, 11.3 to 41.7) and 13.7 (95% CI, 5.0 to 22.4) seconds slower than baseline, respectively. After flumazenil reversal, the contralateral hand (P = 0.99) and ipsilateral hand (P = 0.187) performed 1.2 (95% CI, -3.3 to 5.8) and 1.5 (95% CI, -0.5 to 3.5) seconds slower than baseline, respectively. In the control group, the dominant (P < 0.001) and nondominant hand (P = 0.006) were 2.9 (95% CI, 1.4 to 4.3) and 1.7 (95% CI, 0.5 to 2.9) seconds slower than baseline, respectively. After flumazenil, the dominant hand (P = 0.99) and nondominant hand (P = 0.019) performed 0.2 (95% CI, -0.7 to 1.0) and 1.3 (95% CI, -0.2 to 2.4) seconds faster than baseline, respectively.

Conclusions

In patients with eloquent area gliomas, mild sedation with midazolam induced motor coordination deficits in upper limbs. This deficit was almost completely reversed by the benzodiazepine antagonist flumazenil, suggesting that this is a reversible abnormality linked to occupation of the receptor by midazolam.