Development of an enhanced recovery protocol after laser ablation surgery protocol: a preliminary analysis.

Background: Enhanced recovery after surgery (ERAS) programs are a model of care that aim to improve patient outcomes, reduce complications, and facilitate recovery while reducing healthcare-associated costs and admission length. While such programs have been developed in other surgical subspecialties, there have yet to be guidelines published specifically for laser interstitial thermal therapy (LITT). Here we describe the first multidisciplinary ERAS preliminary protocol for LITT for the treatment of brain tumors. Methods: Between the years 2013 and 2021, 184 adult patients consecutively treated with LITT at our single institution were retrospectively analyzed. During this time, a series of pre, intra, and postoperative adjustments were made to the admission course and surgical/anesthesia workflow with the goal of improving recovery and admission length. Results: The mean age at surgery was 60.7 years with a median preoperative Karnofsky performance score of 90 ± 13. Lesions were most commonly metastases (50%) and high-grade gliomas (37%). The mean length of stay was 2.4 days, with the average patient being discharged 1.2 days after surgery. There was an overall readmission rate of 8.7% with a LITT-specific readmission rate of 2.2%. Three of 184 patients required repeat intervention in the perioperative period, and there was one perioperative mortality. Conclusions: This preliminary study shows the proposed LITT ERAS protocol to be a safe means of discharging patients on postoperative day 1 while preserving outcomes. Although future prospective work is needed to validate this protocol, results show the ERAS approach to be promising for LITT.

Prevalence of discordant elevations of state entropy and bispectral index in patients at amnestic sevoflurane concentrations: a historical cohort study.

BACKGROUND: Processed electroencephalogram (EEG) monitors help assess the hypnotic state during general anesthesia or sedation. Maintaining the bispectral index (BIS) or state entropy (SE) between 40 and 60 has been recommended to mitigate anesthesia awareness. Nonetheless, SEs > 70 were frequently observed at end-tidal sevoflurane concentrations unlikely to allow awareness. We sought to determine the prevalence of elevated discordant measurements during BIS and SE monitoring. METHODS: Electronic data collected over 11 months at two academic hospitals were retrospectively reviewed. At the hospital using SE, all cases were included with patients ≥ 18 yr and sevoflurane administered for at least 30 min during surgery. A cohort of cases propensity matched by age and American Society of Anesthesiologist Physical Status were selected from the hospital using BIS. Elevated discordant EEG indices were defined as values > 70 occurring during stable end-tidal sevoflurane concentrations > 1.5%. The odds ratio (OR) based on the probability of a case having at least one elevated discordant SE or BIS lasting ≥ two minutes (primary endpoint) was calculated. RESULTS: At each hospital, 3,690 cases were studied. The mean (95% confidence interval [CI]) incidence of cases with at least one interval of an elevated discordant EEG index lasting at least two minutes was 3.6% (2.8% to 4.4%) for SE compared with 0.24% (0.17% to 0.27%) for BIS (pooled OR, 17.0; 95% CI, 8.3 to 34.7; P < 0.001). CONCLUSIONS: The prevalence of an elevated discordant EEG index is much greater with SE than with BIS. Elevated index values occurring at anesthetic concentrations well above the awareness threshold need to be assessed to determine if they indicate an inadequate depth of anesthesia requiring treatment or if they simply reflect the underlying monitoring algorithm.

Perioperative use of bispectral (BIS) monitor for a pressure ulcer patient with locked-in syndrome (LIS).

The bispectral (BIS) monitor uses brain electroencephalographic data to measure the depth of sedation and pharmacological response during anaesthetic procedures. In this case, the BIS monitor was used for another purpose, to demonstrate postoperatively to the nursing staff that a patient with history of locked-in syndrome (LIS), who underwent pressure ulcer debridement, had periods of wakefulness and apparent sensation, even with his eyes closed. Furthermore, as patients with LIS can feel pain, despite being unable to move, local block or general anaesthesia should be provided for sharp surgical debridement and other painful procedures. This use of the BIS has shown that as a general rule, the staff should treat the patient as though he might be awake and sensate even if he does not open his eyes or move his limbs. The goal of this study was to continuously monitor pain level and communicate these findings to the entire wound team, i.e. anaesthesiologists, surgeons and nurses.

Isoproterenol infusion increases level of consciousness during catheter ablation of atrial fibrillation.

INTRODUCTION: The objective of this study was to determine the effects of isoproterenol infusion on level of consciousness during ablation using total intravenous anesthesia. METHODS AND RESULTS: Seven patients undergoing total intravenous anesthesia for atrial fibrillation ablation were monitored for level of consciousness using bispectral EEG levels (BIS). Isoproterenol infusion was performed after the ablation during anesthesia. BIS levels prior to, during, and post-isoproterenol infusion were recorded and correlated to isoproterenol infusion doses. In all patients, BIS levels significantly increased during isoproterenol infusion (median BIS prior to infusion, 46; during infusion, 64 (p < 0.02)). With a subsequent increase in anesthetic medication, BIS levels could again be reduced. CONCLUSION: Isoproterenol infusion alters consciousness level during total intravenous anesthesia for atrial fibrillation ablation. BIS monitoring is a novel way to modulate anesthesia during ablation to potentially optimize patient comfort and ablation success.

The effect of dexmedetomidine on perioperative hemodynamics in patients undergoing craniotomy.

BACKGROUND: The perioperative course of patients undergoing intracranial surgery is frequently complicated by hypertensive episodes. Dexmedetomidine (DEX), an alpha-2 adrenoreceptor agonist, is gaining popularity in neuroanesthesia, because its sympatholytic and antinociceptive properties may improve hemodynamic stability at critical moments of surgery. We designed this study to assess the efficacy of DEX in controlling hypertensive responses in patients undergoing intracranial surgery. METHODS: Patients scheduled for elective craniotomy were randomly assigned to receive either sevoflurane-opioid or sevoflurane-opioid-DEX anesthesia. Bispectral index was used to maintain a similar level of hypnosis in both groups (40-50). Opioids, sevoflurane, and vasoactive medications were titrated in a routine manner, at the discretion of the blinded anesthesiologist managing the case, to maintain systolic blood pressure (SBP) targeted within 90-130 mm Hg and heart rate (HR) between 50 and 90 bpm. Hemodynamic variables were continuously recorded and stored on a computer for analysis. Efficacy of the anesthetic technique in controlling SBP or HR is inversely proportional to the area under the curve (AUC) outside the targeted range. Areas under the curves above and below targeted ranges for SBP-time (AUCsbp mm Hg*min/h) and HR-time (bpm*min/h) were compared. Coefficient of variation was used to assess hemodynamic stability. RESULTS: Seventy-two patients were recruited for the study. Computerized records of 56 patients only were analyzed because of technical problems with data collection in 14 cases. AUCsbp for above the targeted range was significantly lower for patients in the DEX group (P=0.044). The coefficient of variation for SBP or HR did not differ between groups. A significantly smaller proportion of patients in the DEX group required treatment with antihypertensive medications (12 of 28, 42% vs 24 of 28, 86%, P=0.0008). The DEX group required fewer opioids in the intraoperative period, but there were no differences in the use of sevoflurane. In the postanesthesia care unit, patients in the DEX group had fewer hypertensive episodes (1.25+/-1.55 vs 2.50+/-2.00, P=0.0114) and were discharged earlier (91+/-17 vs 130+/-27 min, P<0.0001). There were no differences in the requirement for postoperative opioids or antiemetics. CONCLUSIONS: By using indices, which assess a global hemodynamic stability of the anesthetic, we determined that intraoperative DEX infusion was effective for blunting the increases in SBP perioperatively. The use of DEX did not increase the incidence of hypotension or bradycardia, common side effects of the drug.

On the use of multivariable piecewise-linear models for predicting human response to anesthesia.

The standard modeling paradigm used to describe the relationship between input anesthetic agents and output patient endpoint variables are single-input single-output pharmacokinetic-pharmacodynamic (PK-PD) compartment models. In this paper, we propose the use of multivariable piecewise-linear models to describe the relations between inputs that include anesthesia, surgical stimuli and disturbances to a variety of patient output variables. Subspace identification methods are applied to clinical data to construct the models. A comparison of predicted and measured responses is completed, which includes predictions from PK-PD models, and piecewise-linear time-invariant models.