Perception of auditory stimuli during general anesthesia and its effects on patient outcomes: a systematic review and meta-analysis.

PURPOSE: Interest in implicit memory formation and unconscious auditory stimulus perception during general anesthesia has resurfaced as perioperative music has been reported to produce beneficial effects. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating explicit and implicit memory formation during general anesthesia and its effects on postoperative patient outcomes and recovery. SOURCE: We performed a systematic literature search of Embase, Ovid Medline, and Cochrane Central from inception date until 15 October 2020. Eligible for inclusion were RCTs investigating intraoperative auditory stimulation in adult surgical patients under general anesthesia in which patients, healthcare staff, and outcome assessors were all blinded. We used random effects models for meta-analyses. This study adhered to the PRISMA guidelines and was registered in PROSPERO (CRD42020178087). PRINCIPAL FINDINGS: Fifty-three (4,200 patients) of 5,859 identified articles were included. There was evidence of implicit memory formation in seven out of 17 studies (41%) when assessed using perceptual priming tasks. Mixed results were observed on postoperative behavioural and motor response after intraoperative suggestions. Intraoperative music significantly reduced postoperative pain (standardized mean difference [SMD], -0.84; 95% confidence interval [CI], -1.1 to -0.57; P < 0.001; I2 = 0; n = 226) and opioid requirements (SMD, -0.29; 95% CI, -0.57 to -0.015; P = 0.039; I2 = 36; n = 336), while positive therapeutic suggestions did not. CONCLUSION: The results of this systematic review and meta-analysis show that intraoperative auditory stimuli can be perceived and processed during clinically adequate, general anesthesia irrespective of surgical procedure severity, leading to implicit memory formation without explicit awareness. Intraoperative music can exert significant beneficial effects on postoperative pain and opioid requirements. Whether the employed intraoperative anesthesia regimen is of influence is not yet clear.

RéSUMé: OBJECTIF: L'intérêt pour la création de mémoire implicite et la perception inconsciente de stimuli auditifs pendant l'anesthésie générale a refait surface depuis qu'il a été rapporté que l'audition de musique périopératoire produisait des effets bénéfiques. Nous avons mené une revue systématique et une méta-analyse des études randomisées contrôlées (ERC) évaluant la création de mémoire explicite et implicite pendant l'anesthésie générale et ses effets sur les devenirs postopératoires et le rétablissement des patients. SOURCES: Nous avons effectué une recherche documentaire systématique dans les bases de données Embase, Ovid Medline et Cochrane Central depuis leur date de création jusqu'au 15 octobre 2020. Étaient admissibles à l'inclusion les ERC évaluant la stimulation auditive peropératoire chez les patients chirurgicaux adultes sous anesthésie générale, dans lesquelles les patients, le personnel de soins de santé et les évaluateurs des devenirs étaient tous en aveugle. Nous avons utilisé des modèles à effets aléatoires pour les méta-analyses. Cette étude a respecté les lignes directrices PRISMA et a été enregistrée dans le registre PROSPERO (CRD42020178087). CONSTATATIONS PRINCIPALES: Cinquante-trois des 5859 articles identifiés (4200 patients) ont été inclus. Sept études sur 17 (41 %) comportaient des données probantes concernant la création de mémoire implicite lorsqu'elle était évaluée à l'aide de tâches d'amorçage perceptif. Des résultats mitigés ont été observés sur la réponse comportementale et motrice postopératoire après des suggestions peropératoires. La musique peropératoire a considérablement réduit la douleur postopératoire (différence moyenne standardisée [DMS], -0,84; intervalle de confiance [IC] de 95 %, -1,1 à -0,57; P < 0,001; I2 = 0; n = 226) et les besoins en opioïdes (DMS, -0,29; IC 95 %, -0,57 à -0,015; P = 0,039; I2 = 36; n = 336), mais pas les suggestions thérapeutiques positives. CONCLUSION: Les résultats de cette revue systématique et méta-analyse montrent que les stimuli auditifs peropératoires peuvent être perçus et traités pendant une anesthésie générale cliniquement adéquate, indépendamment de la gravité de l'intervention chirurgicale, menant à la création de mémoire implicite sans conscience explicite. La musique peropératoire peut avoir des effets bénéfiques significatifs sur la douleur postopératoire et les besoins en opioïdes. Il n'est pas encore possible de déterminer si le type d'anesthésie peropératoire utilisé a une influence.

The effect of preferred music on mental workload and laparoscopic surgical performance in a simulated setting (OPTIMISE): a randomized controlled crossover study.

BACKGROUND: Worldwide, music is commonly played in the operation room. The effect of music on surgical performance reportedly has varying results, while its effect on mental workload and key surgical stressor domains has only sparingly been investigated. Therefore, the aim is to assess the effect of recorded preferred music versus operating room noise on laparoscopic task performance and mental workload in a simulated setting. METHODS: A four-sequence, four-period, two-treatment, randomized controlled crossover study design was used. Medical students, novices to laparoscopy, were eligible for inclusion. Participants were randomly allocated to one of four sequences, which decided the exposure order to music and operation room noise during the four periods. Laparoscopic task performance was assessed through motion analysis with a laparoscopic box simulator. Each period consisted of ten alternating peg transfer tasks. To account for the learning curve, a preparation phase was employed. Mental workload was assessed using the Surgery Task Load Index. This study was registered with the Netherlands Trial Register (NL7961). RESULTS: From October 29, 2019 until March 12, 2020, 107 participants completed the study, with 97 included for analyzation. Laparoscopic task performance increased significantly during the preparation phase. No significant beneficial effect of music versus operating room noise was observed on time to task completion, path length, speed, or motion smoothness. Music significantly decreased mental workload, reflected by a lower score of the total weighted Surgery Task Load Index in all but one of the six workload dimensions. CONCLUSION: Music significantly reduced mental workload overall and of several previously identified key surgical stressor domains, and its use in the operating room is reportedly viewed favorably. Music did not significantly improve laparoscopic task performance of novice laparoscopists in a simulated setting. Although varying results have been reported previously, it seems that surgical experience and task demand are more determinative.