Dataset Information

Anesthetic Impacts on the Oculocardiac Reflex: Evidence from a Large, Observational Study.

ABSTRACT:

Background

The oculocardiac reflex (OCR) is a sudden vagal bradycardia that can be elicited by traction on an extraocular muscle. Bradycardia is highly variable from case to case necessitating a large sample size to observe small to moderate impact on OCR. While the surgeon's tissue manipulation has immediate impact on OCR and individual patients may have some proclivity to OCR, we sought to characterize the impact on OCR by the anesthesiologist.

Methods

From 1992 to 2019, during routine, community outpatient general anesthetic strabismus surgery, oculocardiac reflex was prospectively observed utilizing a uniform 10-second, 200 gram square wave tension on each extraocular muscle. Anesthetic parameters were recorded and analyzed with double-cohort design and non-parametric statistics and correlations. We define %OCR as the maximally tension-altered heart rate and a percent of stable pre-tension heart rate.

Results

The median (IQR) confidence intervals OCR for 2527 initial cases was 89% (67% to 97%) without anticholinergic, and 99% (95% to 100%) in 165 patients with anticholinergic. OCR was 81% (62% to 96%) in 1034 with opioids and to 75% (60% to 95%) in 59 with dexmedetomidine and in 189 with IV dexamethasone to 72% (56% to 92%) There was a significant (p<0.01 Kruskal-Wallis) impact on OCR by various opioids, muscle relaxants and inhalational agents. Linear regression showed significant inhibitory impact on OCR by increased inhalational agent depth and by lower exhaled CO₂.

Conclusion

The anesthesiologist can block OCR with sufficient anticholinergics, deeper inhalational agents and robust ventilation, and can augment OCR with opioids, dexmedetomidine and apparently also with dexamethasone.

Clinical trials registry

NCT04353960.

SUBMITTER: Arnold RW

PROVIDER: S-EPMC7944370 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Publications

Anesthetic Impacts on the Oculocardiac Reflex: Evidence from a Large, Observational Study.

Arnold Robert W RW Jansen Stephen S Seelig Joseph C JC Glasionov Mikhail M Biggs Russell E RE Beerle Brion B

Clinical ophthalmology (Auckland, N.Z.) 20210305

<h4>Background</h4>The oculocardiac reflex (OCR) is a sudden vagal bradycardia that can be elicited by traction on an extraocular muscle. Bradycardia is highly variable from case to case necessitating a large sample size to observe small to moderate impact on OCR. While the surgeon's tissue manipulation has immediate impact on OCR and individual patients may have some proclivity to OCR, we sought to characterize the impact on OCR by the anesthesiologist.<h4>Methods</h4>From 1992 to 2019, during ...[more]

PMID: 33716499

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Project description:IntroductionOphthalmic surgery is assumed to be safe, but some operations require general anaesthesia which is associated with a number of potential complications. In addition, adverse cardiovascular symptoms, such as severe slowing of the heart rate and, in some cases, cardiac arrest may occur due to the surgical technique. The aim of this study was to determine whether it is possible to predict the occurrence of oculocardiac reflex (OCR) based on heart rate variability (HRV) analysis for autonomic nervous system (ANS) activity assessment measured prior to the induction of anaesthesia and immediately before eyeball traction.MethodsFifty-two adults of both sexes (age range 18-65 years) with American Society of Anesthesiologists (ASA) physical status class 1 and 2 were enrolled in this study. All patients had underwent episcleral buckling under general anaesthesia. High-frequency (HF) changes in HRV are thought to reflect parasympathetic impulse transmission, whereas low-frequency (LF) changes reflect both sympathetic and parasympathetic activity. However, in practice, LF changes can be considered to reflect sympathetic changes. Thus, the LF/HF ratio reflects the actual balance between sympathetic and parasympathetic activity. Based on that, frequency domain HRV parameters from 5-min Holter electrocardiogram recordings before anaesthesia induction and before eyeball traction were used for the analysis. The statistical analysis also included patient age, sex, ASA status and preanaesthesia and premanoeuvre heart rate and blood pressure.ResultsData from 42 patients were analysed. Oculocardiac reflex was observed in 32 patients (76.2%). No difference was found in the analysed parameters between patients with and without oculocardiac reflex. There was no relationship between the incidence of the OCR and the analysed parameters.ConclusionThe prediction of OCR based on initial ANS tone was not possible, and the initial heart rate, blood pressure, age, sex, and ASA status were not helpful for the identification of patients at risk of this reflex.Trial registrationClinicalTrials.gov identifier no.: NCT01714362.

Project description:BackgroundThe oculocardiac reflex (OCR), bradycardia that occurs during strabismus surgery is a type of trigemino-cardiac reflex (TCR) is blocked by anticholinergics and enhanced by opioids and dexmedetomidine. Two recent studies suggest that deeper inhalational anesthesia monitored by BIS protects against OCR; we wondered if our data correlated similarly.MethodsIn an ongoing, prospective study of OCR/TCR elicited by 10-s, 200 g square-wave traction on extraocular muscles (EOM) from 2009 to 2013, anesthetic depth was estimated in cohorts using either BIS or Narcotrend monitors. The depth of anesthesia was deliberately varied between first and second EOM tested.ResultsFrom 1992 through 2013, 2833 cases of OCR during strabismus surgery were monitored. Excluding re-operations and cases with anticholinergic, OCR from first EOM traction averaged - 20.2 ± 21.8% (S.D.) with a range from - 95 to + 25% in patients aged 0.2 to 90 (median 6.5) years. We did not find correlation between %OCR and brain wave for 97 patients with BIS monitoring and 91 with Narcotrend. With intra-patient controls between first and second muscle, the difference in brain wave did not correlate with difference in %OCR for BIS (r = 0.0002, 95% C. I -0.0002, 0.002, p = 0.30) or for Narcotrend (r = - 0.001, 95% C. I -0.004, 0.001, p = 0.32). Secondary multi-variable analysis demonstrated significant association on %OCR particularly with BIS monitor, opioid, propofol and nitrous oxide concentration in the second EOM tensioned. Sevoflurane concentration correlated better with BIS monitor in second and third EOM tension. %OCR correlated with younger age (p < 0.01). OCR with rapid onset was more profound than those with gradual onset (difference in means 18, 95% C. I 10, 26%).ConclusionsWe were unable to confirm a direct correlation between brain wave monitor and OCR when using multifactorial anesthetic agents. The discrepency with other studies probably reflects direct impact of inhalational agent concentration and less deliberate quantification of EOM tension. We found no level of BIS or Entropy EEG monitoring that uniformly prevents OCR.Trial registryNCT03663413.Datahttp://www.abcd-vision.org/OCR/OCR%20Brainwave%20de-identified.pdf .

Project description:Surgery patients in Japan undergo routine spirometry testing prior to general anesthesia. The use of a flow sensor during general anesthesia has recently become common. However, it is not certain whether the information derived from flow-volume curves is being adequately used for mechanical ventilation management during general anesthesia. So far, there have been no attempts to calculate airway resistance using flow-volume curves. Therefore, we performed a prospective, observational study to investigate the relationship between pre-anesthetic and intra-anesthetic airway resistance in patients scheduled for surgery under general anesthesia. We calculated pre-anesthetic and intra-anesthetic airway resistance in each patient, based on the slopes of flow-volume curves obtained prior to and during general anesthesia. We also calculated endotracheal tube resistance to correct the intra-anesthetic airway resistance values calculated. A total of 526 patients were included in the study, and 98 patients had a forced expiratory volume in the first second/forced vital capacity ratio of < 70%. Pre-anesthetic airway resistance was significantly higher in patients with airflow obstruction than in those without airflow obstruction (p < 0.001), whereas no significant difference in intra-anesthetic airway resistance was found between patients with and without airflow obstruction during mechanical ventilation (p = 0.48). Pre-anesthetic and intra-anesthetic airway resistance values were closer to each other in patients without airflow obstruction, with a mean difference < 1.0 cmH2O L-1s-1, than in those with airflow obstruction, although these respiratory parameters were significantly different (p < 0.001). Intra-anesthetic airway resistance was not related to the FEV1/FVC ratio, regardless of the degree to which the FEV1/FVC ratio reflected pre-anesthetic airway resistance. As compared with patients with airflow obstruction, the mean difference between pre-anesthetic and intra-anesthetic airway resistance was small in patients without airflow obstruction.

Project description:BackgroundPain detection and treatment is a major challenge in the care of critically ill patients, rendered more complex by the need to take into consideration the risk of insufficient or excessive analgesia. The nociceptive flexion reflex threshold (NFRT) has become the established basis for measuring the level of analgesia in the perioperative context. However, it remains unclear whether NFRT measurement can be usefully applied to mechanically ventilated, analgosedated critically ill patients who are unable to communicate. Therefore, the aim of the present study was to investigate whether there is an association between the NFRT measurement and the Behavioral Pain Scale (BPS) in critically ill, analgosedated, and mechanically ventilated patients and whether the NFRT measurement can also detect potential excessive analgesia.MethodsThis prospective, observational, randomized single-center pilot study included patients admitted to the surgical Intensive Care Unit of University Hospital Ulm, Germany, all of whom were analgosedated and intubated. Major exclusion criteria were defined as the need for the administration of neuromuscular blocking agents or neurological diseases associated with peripheral nerve conduction restriction. Initial NFRT and BPS measurements were conducted within 12 h after admission. A structured pain assessment was performed at least twice daily until extubation throughout the observation period thereafter (Group A: BPS + NFRT, Group B: BPS).Results114 patients were included in the study. NFRT is associated negatively with BPS. NFRT was almost twice as high in patients with a Richmond Agitation Sedation Scale (RASS) score of -5 than in patients with a RASS score ≥ -4 (RASS -5 - NFRT: 59.40 vs. RASS -4 - NFRT: 29.00, p < 0.001).ConclusionsNFRT measurement is associated negatively with the BPS in critically ill patients. NFRT measurement provides guidance for the evaluation of nociceptive processes in patients with RASS scores ≤ -4, in whom analgesia level is often difficult to assess. However, in order to identify excessive analgesia and derive therapeutic consequences, it is necessary to gradually decrease analgesics and sedatives until a stimulus threshold is reached at which the patient does not feel pain.Trial registrationRetrospectively registered in the German Clinical Trials Register, registration number DRKS00021149, date of registration: March 26, 2020. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00021149 .

Dataset Information

Anesthetic Impacts on the Oculocardiac Reflex: Evidence from a Large, Observational Study.

Background

Methods

Results

Conclusion

Clinical trials registry

Publications

Anesthetic Impacts on the Oculocardiac Reflex: Evidence from a Large, Observational Study.

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