Comparison of Dexmedetomidine, Lidocaine, and Fentanyl in Attenuation Hemodynamic Response of Laryngoscopy and Intubation in Patients Undergoing Cardiac Surgery

Noradrenergic suppression to reduce electroencephalographic arousal after intubation: a randomised, placebo-controlled trial

Background

Intraoperative awareness, without explicit recall, occurs after induction of anaesthesia in approximately 10% of persons under 40 yr of age. Most anaesthetic agents minimally suppress the noradrenergic system. We hypothesised that addition of dexmedetomidine, which suppresses noradrenergic activity, may reduce encephalographic (EEG) arousal in response to tracheal intubation; such an effect would lay the foundation for future studies of dexmedetomidine in reducing intraoperative awareness.

Methods

A single-site randomised, placebo-controlled trial with sex-based stratification was conducted. Participants, aged 18-40 yr old, undergoing intubation for general anaesthesia were eligible for recruitment and randomly allocated to receive dexmedetomidine or placebo. Dexmedetomidine (0.5 μg kg-1) was given as a 5-min loading dose before induction. Bispectral index (BIS) values were collected during the induction phase of anaesthesia and the isolated forearm technique was used to assess patients' responsiveness before and after tracheal intubation. The primary outcome was the effect of dexmedetomidine on changes in BIS from pre-to postintubation.

Results

A total of 51 patients were recruited and included in the primary analysis. We did not observe an effect of dexmedetomidine on changes in BIS after tracheal intubation (mean difference -1.13, 95% confidence interval [CI] -4.87 to 2.62; p=0.556). Dexmedetomidine reduced the estimated plasma propofol concentration at loss of responsiveness (difference [dexmedetomidine - placebo]: -1.06 μg ml-1, 95% CI -1.66 to -0.46; p<0.001) and before intubation (difference [dexmedetomidine - placebo]: -1.84 μg ml-1, 95% CI -2.79 to -0.90; p<0.001). There was one patient in the placebo group who gave positive responses in the isolated forearm test before and after tracheal intubation.

Conclusions

Dexmedetomidine demonstrated an anaesthetic-sparing effect at induction of anaesthesia but did not prevent EEG arousal after tracheal intubation, as defined by an increase in the BIS value.

Clinical Trial Registration

Australia and New Zealand Clinical Trials Registry (Trial ID: ACTRN12622000754741).

Effect of Vitamin C Infusion on Cerebral Oximetry During General Anesthesia for Carotid Endarterectomy in Diabetic Patients

Background

There is conflicting information about the effect of vitamin C on brain oxygenation during anesthesia.

Objectives

The current study was designed and performed to assess the effect of vitamin C infusion and brain oxygenation with cerebral oximetry on improving brain perfusion during general anesthesia in vascular surgery of diabetic patients.

Methods

This randomized clinical trial was performed on patients candidates for endarterectomy under general anesthesia and referred to Taleghani Hospital in Tehran, Iran, during 2019 - 2020. Considering inclusion criteria, the patients were divided into placebo and intervention groups. The patients in the placebo group received 500 mL of isotonic saline. In the intervention group, the patients received 1 g of vitamin C diluted in 500 mL of isotonic saline by infusion half an hour before anesthesia induction. Patients' oxygen levels were continuously measured by a cerebral oximetry sensor. The patients were put in a supine position for 10 minutes before and after anesthesia. At the end of the surgery, the indicators considered in the study were evaluated.

Results

No considerable difference was observed between systolic and diastolic blood pressure, heart rate, mean arterial pressure, partial pressure of carbon dioxide, oxygen saturation, regional oxygen saturation, supercritical carbon dioxide, and end-tidal carbon dioxide in total and between the two groups in the three stages before and after anesthesia induction and at the end of surgery (P > 0.05). Additionally, there was no significant difference between blood sugar (BS) levels in the study groups (P > 0.05) but in BS levels at three stages before and after anesthesia induction and at the end of the surgery, with a significant difference (P < 0.05).

Conclusions

The amount of perfusion in the two groups and, therefore, in total at the three stages before and after anesthesia induction and at the end of surgery is not different.

Comparison of Fentanyl and Dexmedetomidine in Preventing an Increase in Heart Rate During Intubation Among Patients Undergoing General Anesthesia: A Meta-Analysis

General anesthesia induction, tracheal intubation, extubation, and laryngoscopy are associated with specific hemodynamic changes. Tracheal intubation and laryngoscopy are related to sympathetic stimulation and lead to hypertension and tachycardia. Recent studies have shown that dexmedetomidine is safe and effective as it does not depress respiratory function. This meta-analysis aims to compare the efficacy of dexmedetomidine and fentanyl in preventing an increase in heart rate (HR) during intubation among patients undergoing general anesthesia. A systematic literature search was done using PubMed, Cochrane Library, and Embase to assess studies comparing the efficacy of dexmedetomidine and fentanyl in preventing an increase in HR during intubation. A meta-analysis was done utilizing a random-effects model, and mean differences of HR were determined between fentanyl and dexmedetomidine at baseline, one minute, five minutes, and 10 minutes of intubation. In this meta-analysis, eight randomized control trials were included, involving 548 patients (274 in the fentanyl group and 274 in the dexmedetomidine group). The findings showed that significant difference of HR was significantly lower in the dexmedetomidine group than the fentanyl group at one minute of intubation (mean difference = -8.46; P-value = 0.003), at five minutes of intubation (mean difference = -7.51; P-value = 0.001), and at 10 minutes of intubation (mean difference = -5.15; P-value = 0.030). In the current meta-analysis, dexmedetomidine was better than fentanyl in preventing tachycardia following endotracheal intubation. HR was significantly lower at one minute, five minutes, and 10 minutes after intubation in the dexmedetomidine group compared to the fentanyl group.

Laser Therapy in Lumbar Disc Surgery - A Narrative Review

Introduction: Low back pain is one of the most chronic debilitating conditions involving considerable loss of cash, work, and quality time. Lasers are utilized in different fields of drugs, providing unique advantages. They are useful and advantageous in treating lumbar disc disease. In this research, an attempt is made to examine the role and importance of different lasers in lumbar disc surgeries. Methods: We conducted studies about laser therapy in lumbar disc surgery. Our primary search began with reviewing English-language citations from PubMed and Scopus between 1990 and 2019 using the keywords: (laser therapy) OR (lumbar disc AND disc surgery). The initial search yielded 97 articles. However, about 49 articles were selected and used in the present study. Results: Based on the present study, it can be found that there are several methods of using lasers to treat lumbar disc surgery. These methods all have their strengths and weaknesses. Conclusion: The development of laser lumbar disc surgery can be very helpful due to the reduction of surgical risks and the length of the patients' hospital stay. However, the choice of method used for this type of surgery should be made according to the patient's condition and based on the opinion of the treating physician.