Interleaved Propofol-Ketamine Maintains DBS Physiology and Hemodynamic Stability: A Double-Blind Randomized Controlled Trial

BACKGROUND

The gold standard anesthesia for deep brain stimulation (DBS) surgery is the "awake" approach, using local anesthesia alone. Although it offers high-quality microelectrode recordings and therapeutic-window assessment, it potentially causes patients extreme stress and might result in suboptimal surgical outcomes. General anesthesia or deep sedation is an alternative, but may reduce physiological testing reliability and lead localization accuracy.

OBJECTIVES

The aim is to investigate a novel anesthesia regimen of ketamine-induced conscious sedation for the physiological testing phase of DBS surgery.

METHODS

Parkinson's patients undergoing subthalamic DBS surgery were randomly divided into experimental and control groups. During physiological testing, the groups received 0.25 mg/kg/h ketamine infusion and normal saline, respectively. Both groups had moderate propofol sedation before and after physiological testing. The primary outcome was recording quality. Secondary outcomes included hemodynamic stability, lead accuracy, motor and cognitive outcome, patient satisfaction, and adverse events.

RESULTS

Thirty patients, 15 from each group, were included. Intraoperatively, the electrophysiological signature and lead localization were similar under ketamine and saline. Tremor amplitude was slightly lower under ketamine. Postoperatively, patients in the ketamine group reported significantly higher satisfaction with anesthesia. The improvement in Unified Parkinson's disease rating scale part-III was similar between the groups. No negative effects of ketamine on hemodynamic stability or cognition were reported perioperatively.

CONCLUSIONS

Ketamine-induced conscious sedation provided high quality microelectrode recordings comparable with awake conditions. Additionally, it seems to allow superior patient satisfaction and hemodynamic stability, while maintaining similar post-operative outcomes. Therefore, it holds promise as a novel alternative anesthetic regimen for DBS. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cerebral blood flow autoregulation assessment by correlation analysis between mean arterial blood pressure and transcranial doppler sonography or near infrared spectroscopy is different: A pilot study

PURPOSE

Recently, cerebral autoregulation indices based on moving correlation indices between mean arterial pressure (MAP) and cerebral oximetry (NIRS, ORx) or transcranial Doppler (TCD)-derived middle cerebral artery flow velocity (Mx) have been introduced to clinical practice. In a pilot study, we aimed to evaluate the validity of these indices using incremental lower body negative pressure (LBNP) until presyncope representing beginning cerebral hypoperfusion as well as lower body positive pressure (LBPP) with added mild hypoxia to induce cerebral hyperperfusion in healthy subjects.

METHODS

Five male subjects received continuous hemodynamic, TCD and NIRS monitoring. Decreasing levels of LBNP were applied in 5-minute steps until subjects reached presyncope. Increasing levels of LBPP were applied stepwise up to 20 or 25 mmHg. Normobaric hypoxia was added until an oxygen saturation of 84% was reached. This was continued for 10 minutes. ORx and Mx indices were calculated using previously described methods.

RESULTS

Both Indices showed an increase > 0.3 indicating impaired cerebral autoregulation during presyncope. However, there was no significant difference in Mx at presyncope compared to baseline (p = 0.168). Mean arterial pressure and cardiac output decreased only in presyncope, while stroke volume was decreased at the last pressure level. Neither Mx nor ORx showed significant changes during LBPP or hypoxia. Agreement between Mx and ORx was poor during the LBNP and LBPP experiments (R2 = 0.001, p = 0.3339).

CONCLUSION

Mx and ORx represent impaired cerebral autoregulation, but in Mx this may not be distinguished sufficiently from baseline. LBPP and hypoxia are insufficient to reach the upper limit of cerebral autoregulation as indicated by Mx and ORx.

Influence of Intraoperative Nociception during Hip or Knee Arthroplasty with Supplementary Regional Anaesthesia on Postoperative Pain and Opioid Consumption

Background and Objectives: Early postoperative mobilization is central for postoperative outcomes after lower extremity joint replacement surgery. By providing adequate pain control, regional anaesthesia plays an important role for postoperative mobilization. It was the objective of this study to investigate the use of the nociception level index (NOL) to determine the effect of regional anaesthesia in hip or knee arthroplasty patients undergoing general anaesthesia with additional peripheral nerve block. Materials and Methods: Patients received general anaesthesia, and continuous NOL monitoring was established before anaesthesia induction. Depending on the type of surgery, regional anaesthesia was performed with a Fascia Iliaca Block or an Adductor Canal Block. Results: For the final analysis, 35 patients remained, 18 with hip and 17 with knee arthroplasty. We found no significant difference in postoperative pain between hip or knee arthroplasty groups. NOL increase at the time of skin incision was the only parameter associated with postoperative pain measured using a numerical rating scale (NRS > 3) after 24 h in movement (-12.3 vs. +119%, p = 0.005). There was no association with intraoperative NOL values and postoperative opioid consumption, nor was there an association between secondary parameters (bispectral index, heart rate) and postoperative pain levels. Conclusions: Intraoperative NOL changes may indicate regional anaesthesia effectiveness and could be associated with postoperative pain levels. This remains to be confirmed in a larger study.

Pupillary Pain Index Predicts Postoperative Pain but Not the Effect of Peripheral Regional Anaesthesia in Patients Undergoing Total Hip or Total Knee Arthroplasty: An Observational Study

Background and Objectives: The pupillary pain index (PPI) allows the evaluation of intraoperative nociception by measuring pupillary reaction after a localized electrical stimulus. It was the objective of this observational cohort study to investigate the pupillary pain index (PPI) as a method to evaluate the fascia iliaca block (FIB) or adductor canal block (ACB) sensory areas during general anaesthesia in orthopaedic patients with lower-extremity joint replacement surgery. Materials and Methods: Orthopaedic patients undergoing hip or knee arthroplasty were included. After anaesthesia induction, patients received an ultrasound-guided single-shot FIB or ACB with 30 mL and 20 mL of 0.375% ropivacaine, respectively. Anaesthesia was maintained with isoflurane or propofol/remifentanil. The first PPI measurements were performed after anaesthesia induction and before block insertion, the second at the end of surgery. Pupillometry scores were evaluated in the area of the femoral or saphenous nerve (target) and C3 dermatome (control). Primary outcomes were differences between PPIs before and after peripheral block insertion as well as the relationship between PPIs and postoperative pain scores; secondary outcomes were the relationship between PPIs and opioid requirements after surgery. Results: PPI decreased significantly from the first to the second measurement (4.17 ± 2.7 vs. 1.6 ± 1.2, p < 0.001 for target; 4.46 ± 2.7 vs. 2.17 ± 2.1, p < 0.001 for control). Control and target measurements did not show significant differences. A linear regression analysis showed that early postoperative pain scores could be predicted with intraoperative piritramide with improved prediction after adding PPI scores, PCA opioids and surgery type. Forty-eight-hour pain scores at rest and in movement were correlated with intraoperative piritramide and control PPI after the PNB in movement and with second-postoperative-day opioids and target PPI scores before block insertion, respectively. Conclusions: While the effect of an FIB and ACB could not be shown with PPI postoperative pain scores due to a large effect of opioids, perioperative PPI was shown to be associated with postoperative pain. These results suggest that preoperative PPI may be used to predict postoperative pain.

The Impact of a 22-Month Multistep Implementation Program on Speaking-Up Behavior in an Academic Anesthesia Department

BACKGROUND

Speaking-up is a method of assertive communication that increases patient safety but often encounters barriers. Numerous studies describe programs introducing speaking-up with varying success; the common denominator seems to be the need for a multimodal and sustained approach to achieve the required change in behavior and culture for safer health care.

METHODS

Before implementing a 22-month multistep program for establishing and strengthening speaking-up at our institution, we assessed perceived safety culture using the "Safety Attitudes Questionnaire." After program completion, participants completed parts of the same Safety Attitudes Questionnaire relevant to speaking-up, and preresult and postresult were compared. In addition, levels of speaking-up and assertive communication were compared with a Swiss benchmark using results from the "Speaking-up About Patient Safety Questionnaire."

RESULTS

Safety Attitudes Questionnaire scores were significantly higher after program completion in 2 of 3 answered questions (median [first quartile, third quartile), 5.0 [4.0, 5.0] versus 4.0 [4.0, 5.0], P = 0.0002, and 5.0 [4.0, 5.0] versus 4.0 [4.0, 4.0] P = 0.002; n = 34). Our composite score on the Speaking-up About Patient Safety Questionnaire was significantly higher (mean ± SD, 5.9 ± 0.7 versus 5.2 ± 1.0; P < 0.001) than the benchmark (n = 65).

CONCLUSIONS

A long-term multimodal program for speaking-up was successfully implemented. Attitude and climate toward safety generally improved, and postprogram perceived levels of assertive communication and speaking-up were higher than the benchmark. These results support current opinion that multimodal programs and continued effort are required, but that speaking-up can indeed be strengthened.

Asleep DBS under ketamine sedation: Proof of concept

BACKGROUND

Deep brain stimulation (DBS) is commonly and safely performed for selective Parkinson's disease patients. Many centers perform DBS lead positioning exclusively under local anesthesia, to optimize brain microelectrode recordings (MER) and testing of stimulation-related therapeutic and side effects. These measures enable physiological identification of the DBS borders and subdomains based on electrophysiological properties like firing rates and patterns, intra-operative evaluation of therapeutic window, and improvement of lead placement accuracy. Nevertheless, due to the challenges of awake surgery, some centers use sedation or general anesthesia, despite the distortion of discharge properties and interference with clinical testing, resulting in potential impact on surgical outcomes. Thus, there is a need for a novel anesthesia regimen that enables sedation without compromising intra-operative monitoring.

OBJECTIVE

This open-label study investigates the use of low-dose ketamine for conscious sedation during microelectrode recordings and lead positioning in subthalamic nucleus (STN) DBS for Parkinson's disease patients.

METHODS

Three anesthetic regimens were retrospectively compared in 38 surgeries (74 MER trajectories, 5962 recording sites) across three DBS centers: 1) Interleaved propofol-ketamine (PK), 2) Interleaved propofol-awake (PA), and 3) Fully awake (AA).

RESULTS

All anesthesia regimens achieved satisfactory MER. Detection of STN borders and subdomains by expert electrophysiologist was similar between the groups. Electrophysiological signature of the STN under ketamine was not inferior to either control group. All patients completed stimulation testing.

CONCLUSIONS

This study supports a low-dose ketamine anesthesia regimen for DBS which allows microelectrode recordings and stimulation testing that are not inferior to those conducted under awake and propofol-awake regimens and may optimize patient experience. A prospective double-blind study that would also compare patients' satisfaction level and clinical outcome should be performed to confirm these findings.

The relationship between resited epidural catheters after secondary epidural catheter failure and vaginal delivery: A retrospective case-control study

BACKGROUND

There are cases where epidural analgesia is initially effective but subsequently fails and needs to be resited. We evaluated the rate of normal vaginal delivery and operative delivery among parturients who had resited epidurals compared to parturients with epidurals that were not resited.

METHODS

A retrospective electronic medical review of parturients with a singleton gestation attempting normal vaginal delivery under epidural analgesia between the years 2012-2016 was conducted. Resited epidurals were defined as epidurals that were considered effective but subsequently removed and reinserted. For each resited epidural, two previous and two consecutive deliveries of parturients with normally functioning epidural catheter inserted by the same anesthesiologist were matched controls (non-resited epidurals).

RESULTS

There were 35,984 attempted vaginal deliveries with 118 resited epidurals and 472 non-resited epidurals. When adjusted for nulliparity, oxytocin administration, sex and weight of the baby, and maternal BMI, labor epidural catheter replacement was not associated with need for instrumental or caesarean delivery, (OR 1.5, 95% CI 0.91-2.49, P = .11).

CONCLUSIONS

Need for labor epidural catheter replacement does not appear to be associated with need for operative delivery based on this single-centre cohort analysis.

The effect of preoperative anxiety on phenylephrine dose during cesarean delivery: An open controlled one-arm clinical trial

BACKGROUND

We performed an open controlled one-arm clinical trial to assess whether preoperative anxiety influences phenylephrine dosage required to maintain normotension during cesarean section under spinal anesthesia.

METHODS

Ninety-four parturients undergoing elective cesarean delivery under spinal anesthesia were included. Anxiety levels were measured using a verbal numerical scale anxiety score (0-10). Phenylephrine infusion to prevent hypotension was adjusted by a standard algorithm. The primary outcome was total phenylephrine dose. Linear uni- and multivariate regressions were performed to assess the relationship between preoperative anxiety and the outcome. P < .05 was considered statistically significant.

RESULTS

We found no association between preoperative anxiety and phenylephrine dosage (R²  = 0.05). Taking the number of attempts for spinal anesthesia and surgical time into account did not lead to a significant improvement of the regression model.

CONCLUSION

In conclusion, we did not find a large independent effect of preoperative anxiety on phenylephrine dose required to maintain normotension in our cohort. We believe that spinal hypotension and phenylephrine dose requirement are multifactorial and anxiety is only one of the factors in this complex interaction.