Effect of Esmolol and Lidocaine on Agitation in Awake Phase of Anesthesia Among Children: A Double-Blind, Randomized Clinical Study
Introduction
Sevoflurane is a widely used anesthetic agent in pediatric anesthesia due to its rapid onset, minimal airway irritation, and hemodynamic stability. However, a significant drawback of sevoflurane is the high incidence of emergence agitation (EA) in children, ranging from 50% to 80%. Emergence agitation is characterized by restlessness, inconsolable crying, and disorientation during the transition from anesthesia to full consciousness. This phenomenon is particularly prevalent after strabismus surgery, where patients often have their eyes covered postoperatively, exacerbating anxiety and agitation.
Agitation in children not only causes distress but also delays recovery room discharge and increases the risk of injury. While several pharmacological interventions, such as midazolam and dexmedetomidine, have been explored to mitigate EA, these agents are associated with adverse effects, including delayed awakening, hypotension, and bradycardia. Lidocaine, known for its ability to reduce airway stimulation and postoperative sore throat, has shown potential in alleviating agitation. Similarly, esmolol, a short-acting beta-blocker, has been used to maintain hemodynamic stability and reduce stress during surgery. However, the combined use of esmolol and lidocaine in managing EA has not been extensively studied.
This study aimed to evaluate the efficacy of esmolol and lidocaine, individually and in combination, in reducing emergence agitation in children undergoing strabismus surgery under sevoflurane anesthesia.
Methods
This double-blind, randomized, controlled clinical trial enrolled 84 children aged 3 to 9 years with American Society of Anesthesiologists (ASA) physical status I or II, scheduled for strabismus surgery. Patients with cardiac, respiratory, or mental disorders were excluded. The participants were randomly assigned to one of three groups: a control group receiving saline, a lidocaine group receiving intravenous lidocaine 1.5 mg/kg, and an esmolol-lidocaine (EL) group receiving intravenous esmolol 0.5 mg/kg and lidocaine 1.5 mg/kg.
Anesthesia was induced with thiopental 5 mg/kg and rocuronium 0.6 mg/kg, followed by maintenance with 2% sevoflurane in a mixture of oxygen and air. Dexamethasone 0.5 mg/kg was administered before surgery to reduce inflammation. At the end of surgery, the control group received saline, the lidocaine group received lidocaine, and the EL group received both esmolol and lidocaine.
Agitation was assessed using the Objective Pain Score (OPS), Cole 5-Point Score (CPS), and Richmond Agitation Sedation Scale (RASS) at four time points: at the end of surgery, on arrival in the recovery room, and 10 and 30 minutes after arrival. The primary outcome was the severity of postoperative agitation, while secondary outcomes included vital signs, pain severity, fentanyl use, extubation time, and recovery time.
Results
The EL group demonstrated significantly lower OPS and RASS scores compared to the control and lidocaine groups during the transition from anesthesia to the recovery room. Specifically, the EL group had OPS scores of 0 (0–4) and RASS scores of -4 [(-5)–1] upon awakening, and OPS scores of 0 (0–8) and RASS scores of -1 [(-5)–3] upon arrival in the recovery room (P<0.05). No significant differences in agitation scores were observed among the groups at other time points.
The incidence of agitation, defined as an OPS score of 4 or higher, was 20% in the EL group, 63% in the lidocaine group, and 45% in the control group. The EL group showed a statistically significant reduction in agitation compared to both the control and lidocaine groups (P=0.01 and P=0.00, respectively).
Demographic data, including age, weight, sex, operation duration, anesthesia duration, extubation time, and recovery time, were comparable among the three groups. Hemodynamic parameters, such as systolic blood pressure and heart rate, were slightly lower in the EL group upon awakening but stabilized over time.
Discussion
The findings of this study suggest that the combination of esmolol and lidocaine effectively reduces emergence agitation in children undergoing strabismus surgery under sevoflurane anesthesia. The analgesic and sedative effects of esmolol, combined with lidocaine’s ability to attenuate airway stimulation, likely contributed to the observed reduction in agitation.
Lidocaine has been shown to reduce postoperative sore throat and coughing by inhibiting sensory C fibers in the airway and reducing mucosal stimulation. Esmolol, on the other hand, acts as a beta-blocker, reducing wakefulness and cortical arousal by blocking beta receptors in the reticular activating system. The synergistic effect of these two agents appears to provide a more comprehensive approach to managing agitation compared to either drug alone.
The study’s results align with previous research demonstrating the benefits of esmolol in reducing anesthetic requirements and postoperative pain. However, the use of esmolol in pediatric patients remains limited due to concerns about its safety and duration of action. The short-acting nature of esmolol may explain why its effects on agitation were observed only during the immediate postoperative period.
Limitations
This study has several limitations. First, it did not distinguish between patients with one or both eyes covered, which may have influenced the severity of agitation. Second, agitation persisting for 10 minutes after arrival in the recovery room was treated with fentanyl, potentially confounding the results. Third, the RASS, which is typically used in intensive care settings, may not fully capture the nuances of pediatric agitation. Finally, the study did not include a group receiving esmolol alone, making it difficult to isolate the individual contributions of esmolol and lidocaine.
Conclusion
The administration of esmolol and lidocaine at the end of anesthesia significantly reduces emergence agitation in children undergoing strabismus surgery under sevoflurane anesthesia. This combination therapy offers a promising approach to improving postoperative recovery and reducing the risk of complications associated with agitation. Further research is needed to explore the broader applicability of this intervention in other surgical contexts and to evaluate the safety and efficacy of esmolol in pediatric patients.
doi.org/10.1097/CM9.0000000000000141
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