Dexmedetomidine-induced hemodynamic instability in patients undergoing orthopedic upper limb surgery under brachial plexus block: a retrospective study

Predictors for Dexmedetomidine Requirement for Sedation under Regional Anesthesia

(1) Background: This prospective observational study aimed to investigate the predictors affecting DMT requirements for sedation during regional anesthesia. (2) Method: A total of 108 patients who received regional anesthesia with intravenous DMT administration for orthopedic upper- or lower-extremity surgery were enrolled. Following successful regional anesthesia, DMT was administered at a rate of 4 µg/kg/h until reaching loss of consciousness (LOC). The administered dose of DMT per body weight until LOC (DMTLOC; µg/kg) was evaluated. The infusion was maintained at a rate of 0.2-0.7 µg/kg/h during the surgery. At the end of surgery, the elapsed time to a BIS value of 90 (TBIS90; s) was recorded. Linear regression models were used to identify potential predictors of DMTLOC and TBIS90. (3) Results: One hundred patients were analyzed. There were negative relationships between DMTLOC and age (r = -0.297, p = 0.003) and DMTLOC and body mass index (BMI) (r = -0.425, p < 0.001), respectively. Multiple linear regression models revealed that both increasing age and BMI were significantly related to DMTLOC (r2 = 0.259, p < 0.001), but those variables showed no association with TBIS90. (4) Conclusions: The results of this study suggest that initial loading of DMT should be carefully titrated to minimize risk in elderly and obese surgical populations.

Monitored Anesthesia Care in Minimally Invasive Spine Surgery-A Retrospective Case Series Study

Background and Objectives: Minimally invasive spine surgery (MISS) under monitored anesthesia care (MAC) has emerged as a treatment modality for spinal radiculopathy. It is essential to secure the airway and guarantee spontaneous respiration without endotracheal intubation during MISS in a prone position. Materials and Methods: To evaluate the feasibility and safety of MAC with dexmedetomidine during MISS, we retrospectively reviewed clinical cases. A retrospective review of medical records was conducted between September 2015 and June 2016. A total of 17 patients undergoing MISS were included. Vital signs were analyzed every 15 min. The depth of sedation was assessed using the bispectral index (BIS) and the frequency of rescue sedatives. Adverse events during anesthesia, including bradycardia, hypotension, respiratory depression, postoperative nausea, and vomiting, were evaluated. Results: All cases were completed without the occurrence of airway-related complications. None of the patients needed conversion to general anesthesia. The median maintenance dosage of dexmedetomidine for adequate sedation was 0.40 (IQR 0.40-0.60) mcg/kg/hr with a median loading dose of 0.70 (IQR 0.67-0.82) mcg/kg. The mean BIS during the main procedure was 76.46 ± 10.75. Rescue sedatives were administered in four cases (23.6%) with a mean of 1.5 mg intravenous midazolam. After dexmedetomidine administration, hypotension and bradycardia developed in six (35.3%) and three (17.6%) of the seventeen patients, respectively. Conclusions: MAC using dexmedetomidine is a feasible anesthetic method for MISS in a prone position. Hypotension and bradycardia should be monitored carefully during dexmedetomidine administration.

Perioperative Hypotension in Patients Undergoing Orthopedic Upper Extremity Surgery with Dexmedetomidine Sedation: A Retrospective Study

(1) Background: limited data exist regarding the occurrence of hypotension associated with dexmedetomidine use and its risk factors in the context of intraoperative sedation for patients receiving peripheral nerve blocks. (2) Method: This single-center retrospective study assessed the incidence of hypotension in patients undergoing orthopedic upper extremity surgery with brachial plexus blockade. Patients were classified into three groups: group N (non-sedated), group M (midazolam), and group D (dexmedetomidine), based on their primary intraoperative sedative use. The primary outcome was the incidence of perioperative hypotension, defined as systolic blood pressure (SBP) < 90 mmHg or mean blood pressure (MBP) < 60 mmHg, at a minimum of two recorded time points during the intraoperative period and post-anesthesia care unit stay. Multivariable logistic models for the occurrence of hypotension were constructed for the entire cohort and group D. (3) Results: A total of 2152 cases (group N = 445, group M = 678, group D = 1029) were included in the analysis. The odds ratio for the occurrence of hypotension in group D was 5.68 (95% CI, 2.86 to 11.28) compared with group N. Concurrent use of a beta blocker, longer duration of surgery, and lower preoperative SBP and higher preoperative heart rate were identified as significant risk factors. (4) Conclusions: the increased risk of hypotension and the associated factors should be taken into account before using dexmedetomidine in these cases.

Advances in Anesthesia for Shoulder Surgery: A Comprehensive Review of Dexmedetomidine-Enhanced Interscalene Brachial Plexus Block

Surgical procedures on the shoulder pose distinctive challenges in managing pain during the perioperative period, underscoring the importance of exploring innovative anesthesia techniques. This comprehensive review article delves into integrating dexmedetomidine, an alpha-2 adrenergic agonist, within interscalene brachial plexus blocks for shoulder surgery. The review initiates by underscoring the pivotal role of effective anesthesia in shoulder surgery and elucidates the rationale behind investigating dexmedetomidine as an adjunct. It meticulously examines the anatomy and physiology of the brachial plexus, emphasizing its critical significance in shoulder surgery. Furthermore, the article expounds on dexmedetomidine's mechanisms of action and pharmacokinetics, encompassing its safety profile and potential side effects. The conventional interscalene brachial plexus block techniques, along with their limitations and challenges, are discussed, laying the foundation for the integration of dexmedetomidine. The review subsequently delves into exploring the role of dexmedetomidine in regional anesthesia, covering previous studies, mechanisms of action, and the potential advantages of incorporating it into nerve blocks. The review's core concentrates on the practical application of dexmedetomidine-enhanced interscalene brachial plexus blocks. This includes discussions on administration techniques, dosage guidelines, and compelling evidence supporting its utilization. Clinical scenarios where this approach proves most advantageous are thoroughly explored, comparing its effectiveness with traditional techniques in terms of pain control and patient outcomes. A comprehensive examination of relevant clinical trials and case studies highlights the evidence supporting its efficacy. The review also underscores safety considerations associated with dexmedetomidine. It proposes strategies for mitigating risks to ensure patient safety. Insights into future directions and research are provided, encompassing ongoing studies, areas necessitating further investigation, and potential refinements in technique. Finally, the article summarizes key findings, emphasizing the practicality of dexmedetomidine-enhanced interscalene brachial plexus blocks in shoulder surgery and its far-reaching implications for clinical practice and patient care.

Opioid-sparing anesthesia with dexmedetomidine provides stable hemodynamic and short hospital stay in non-intubated video-assisted thoracoscopic surgery: a propensity score matching cohort study

OBJECTIVES

Dexmedetomidine is an alpha-2 agonist with anti-anxiety, sedative, and analgesic effects and causes a lesser degree of respiratory depression. We hypothesized that the use of dexmedetomidine in non-intubated video-assisted thoracic surgery (VATS) may reduce opioid-related complications such as postoperative nausea and vomiting (PONV), dyspnea, constipation, dizziness, skin itching, and cause minimal respiratory depression, and stable hemodynamic status.

METHODS

Patients who underwent non-intubated VATS lung wedge resection with propofol combined with dexmedetomidine (group D) or alfentanil (group O) between December 2016 and May 2022 were enrolled in this retrospective propensity score matching cohort study. Intraoperative vital signs, arterial blood gas data, perioperative results and treatment outcomes were analyzed. Of 100 patients included in the study (group D, 50 and group O, 50 patients), group D had a significantly lower degree of decrement in the heart rate and the blood pressure than group O. Intraoperative one-lung arterial blood gas revealed lower pH and significant ETCO₂. The common opioid-related side effects, including PONV, dyspnea, constipation, dizziness, and skin itching, all of which occurred more frequently in group O than in group D. Patients in group O had significantly longer postoperative hospital stay and total hospital stay than group D, which might be due to opioid-related side effects postoperatively.

CONCLUSIONS

The application of dexmedetomidine in non-intubated VATS resulted in a significant reduction in perioperative opioid-related complications and maintenance with acceptable hemodynamic performance. These clinical outcomes found in our retrospective study may enhance patient satisfaction and shorten the hospital stay.

Comparison of the efficacy of two doses of dexmedetomidine as an adjunct to levobupivacaine in infraclavicular brachial plexus block: prospective double-blinded randomized controlled trial

Background

This prospective, double-blind, randomized, controlled trial compared the efficacy of two dexmedetomidine doses (50 and 100-μg) combined with levobupivacaine on sensory block duration in infraclavicular brachial plexus block. We hypothesized that perineural dexmedetomidine would extend sensory block duration dose-dependently.

Methods

The study included 60 patients aged 20 to 60 years of both sex with an ASA I/II undergoing forearm and hand surgery. The patients were randomly assigned into three equal groups (n = 20) for ultrasound-guided infraclavicular brachial plexus block. The L group received 35-mL 0.5% levobupivacaine plus normal saline, the LD50 group received 35-mL 0.5% levobupivacaine plus 50-μg dexmedetomidine, and the LD100 group received 35-mL 0.5% levobupivacaine plus 100-μg dexmedetomidine. Patients were investigated for onset and duration of sensory blockade, time to first postoperative rescue analgesia, and the total 24-h postoperative morphine requirement.

Results

The LD100 group had a longer sensory block duration (15.55 ± 1.1 h; 95% confidence interval (CI), 15.04–16.06) than the LD50 group (12.8 ± 1.2 h; 95% CI, 12.24–13.36 h) (p < 0.001) or the L group (9.95 ± 1.05 h; 95% CI, 9.46–10.44 h) (p < 0.001). The LD100 group took longer to request postoperative rescue analgesia and required fewer postoperative morphine doses than the LD50 and L groups (P < 0.001).

Conclusions

Sensory block duration was longer with perineural 100-μg dexmedetomidine as an adjunct to levobupivacaine than with 50-μg dexmedetomidine.

Trial registration

This study was approved by the Ethics Committee of Aswan University Hospital (approval number: aswu/125/4/17) (date of registration: 04/04/2017). Furthermore, the trial was retrospectively registered at ClinicalTrial.gov (NCT04729868) with a verification date of January 2021.