Effects of dexmedetomidine as an adjuvant in thoracic paravertebral block on EC50 of propofol for successful laryngeal mask insertion: a randomized controlled trial

Dexmedetomidine as an Adjuvant in Peripheral Nerve Block

Peripheral nerve block technology is important to balanced anesthesia technology. It can effectively reduce opioid usage. It is the key to enhance clinical rehabilitation as an important part of the multimodal analgesia scheme. The emergence of ultrasound technology has accelerated peripheral nerve block technology development. It can directly observe the nerve shape, surrounding tissue, and diffusion path of drugs. It can also reduce the dosage of local anesthetics by improving positioning accuracy while enhancing the block's efficacy. Dexmedetomidine is a highly selective drug α₂-adrenergic receptor agonist. Dexmedetomidine has the characteristics of sedation, analgesia, anti-anxiety, inhibition of sympathetic activity, mild respiratory inhibition, and stable hemodynamics. Numerous studies have revealed that dexmedetomidine in peripheral nerve blocks can shorten the onset time of anesthesia and prolong the time of sensory and motor nerve blocks. Although dexmedetomidine was approved by the European Drug Administration for sedation and analgesia in 2017, it has not yet been approved by the US Food and Drug Administration (FDA). It is used as a non-label drug as an adjuvant. Therefore, the risk-benefit ratio must be evaluated when using these drugs as adjuvants. This review explains the pharmacology and mechanism of dexmedetomidine, the effect of dexmedetomidine on various peripheral nerve block as an adjuvant, and compare it with other types of adjuvants. We summarized and reviewed the application progress of dexmedetomidine as an adjuvant in nerve block and look forward to its future research direction.

A randomised trial: effects of different anesthesia methods on early perioperative pain sensitivity and cellular immune function in patients undergoing radical mastectomy

BACKGROUND

This study sought to investigate the effects of transversus thoracic muscle plane-pectoral nerves (TTP-PECS) block combined with propofol anesthesia on early perioperative pain sensitivity and cellular immune function in patients undergoing radical mastectomy.

METHODS

A total of 115 patients who underwent radical mastectomy for breast cancer at our hospital from January 2019 to January 2021 were selected as the study subjects. The patients were allocated to the control group (n=57) or observation group (n=58) using a random number method. The control group was given simple general anesthesia, and the observation group was given TTP-PECS block combined with propofol anesthesia. The recovery time, pain [visual analogue scoring (VAS)] scores, and incidences of adverse reactions were compared between the 2 groups. Hemodynamic indicators [i.e., heart rate (HR), mean arterial pressure (MAP)], stress indicators [i.e., blood glucose (GLU), epinephrine (E), cortisol (Cor)], and the cellular immune function ofthe2 groups before anesthesia (T0), at the end of operation (T1), 1day after operation (T2) and 3days after operation (T3) were recorded.

RESULTS

The spontaneous respiration recovery time, time to full wakefulness and the extubation time of the observation group were shorter than those of the control group (P<0.05). The observation group had lower VAS scores than the control group at 2, 8, 12, and 24 h after operation (P<0.05). The levels of MAP, HR, GLU, E and Cor in the observation group at T1, T2, and T3 were lower than those in the control group (P<0.05). Compared to the control group, the observation group had increased cluster of differentiation (CD)3+, CD4+, and CD4+/CD8+ cells (P<0.05), but there were no significant differences in CD8+ and natural killer (NK) cells between the 2 groups (P>0.05). The incidence of adverse reactions in the observation group was lower than that in the control group (8.62% vs. 24.56%) (P<0.05).

CONCLUSIONS

TTP-PECS block combined with propofol anesthesia can relieve pain, shorten the recovery time, stabilize the hemodynamic level, and alleviate the stress responses of patients undergoing radical mastectomy with a slight suppression of cellular immune function and high safety.

TRIAL REGISTRATION

Chinese Clinical Trial Registration Center ChiCTR2100048438.