Oculocardiac reflex and oculorespiratory reflex during strabismus surgery under general anesthesia using the laryngeal mask airway with maintenance of spontaneous respiration: A retrospective study

Application of combined anesthesia with spontaneous breathing in the surgery of intertrochanteric fracture of femur in elderly patients

OBJECTIVES

This study aims to investigate the feasibility and safety of combined anesthesia with spontaneous breathing in the operation of intertrochanteric fracture of femur in the elderly.

PATIENTS AND METHODS

Between January 2020 and January 2023, a total of 141 elderly patients (45 males, 96 females; mean age: 72.5±6.8 years; range, 65 to 87 years) who underwent proximal femoral nail anti-rotation (PFNA) surgery for intertrochanteric fracture of femur were included in this single-blind, prospective, randomized-controlled study. The patients were randomly divided into three groups. Group A (experimental group) was a general anesthesia with laryngeal mask airway (LMA) group preserving spontaneous breathing, Group B (control group 1) was a general anesthesia with LMA group for mechanical ventilation, and Group C (control group 2) was a tracheal intubation anesthesia group for mechanical ventilation. The differences of related indexes among the three groups were compared.

RESULTS

The mean onset time of anesthesia (6.23±1.45 vs. 12.78±2.78 vs. 13.73±2.43 min), postoperative recovery time of consciousness (8.13±0.83 vs. 11.34±0.89 vs. 12.45±0.86 min), and postoperative complete awakening time (10.45±2.34 vs. 18.87±2.56 vs. 19.62±2.93 min) were significantly shorter in Group A than in Groups B and C (p<0.05). The duration of analgesic effect was longer in Group A than in Groups B and C (p<0.05). After anesthesia, the Ramsay Sedation Scale and Visual Analog Scale (VAS) scores were significantly lower in Group A than the other groups (p<0.05). The mean Mini-Mental State Examination (MMS) scores were significantly higher in Group A than in Groups B and C (p<0.05). Hemodynamic parameters showed that blood pressure, heart rate, cardiac output, and cardiac index (CI) levels were significantly higher in Group A than the other groups (p<0.05).

CONCLUSION

Our study results indicate that combined anesthesia preserving spontaneous breathing is safe and feasible in the operation of intertrochanteric fracture of femur in the elderly, with faster anesthesia recovery than the mechanical ventilation group.

The role of surgical factors eliciting oculocardiac reflex of patients undergoing orbital tumor surgery: a retrospective study

PURPOSE

Orbital tumors are an interdisciplinary disease, and surgery is one of the main treatment methods. The oculocardiac reflex (OCR) is a condition of surgery for orbital tumors. The aim of this study was to investigate whether there is an association between many surgical factors and the incidence of OCR in orbital tumor surgery.

METHODS

Comparisons were made between patients with and without OCR using the Mann-Whitney test, Fisher's exact test, and Chi-square test. When comparing multiple groups (groups > 2), to explain which two groups had differences, post hoc testing was used for analysis, and the differences between groups were judged according to the adjusted standardized residuals.

RESULTS

The results showed that the incidence of intraoperative OCR was different based on the different exposed operative field locations (p = 0.021). The OCR incidence in those with lesions involving the orbital apex and lesions adhering to extraocular muscles was higher than that of others (p < 0.001 and p = 0.003). In addition, multivariate logistic regression analysis revealed that orbital apex involvement and extraocular muscle adhesion were highly associated with a higher incidence of OCR (p < 0.001 and p = 0.013), while the operative field located in the lateral-superior orbit was highly associated with a lower incidence of OCR (p = 0.029).

CONCLUSION

In orbital tumor surgery under general anesthesia, lesions involving the orbital apex and lesion adhesion to the extraocular muscles were independent risk factors for OCR, and an operative field located in the lateral-superior orbit was a protective factor for OCR.

Prediction of the Occurrence of the Oculocardiac Reflex Based on the Assessment of Heart Rate Variability. An Observational Study

Introduction

Ophthalmic 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.

Methods

Fifty-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.

Results

Data 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.

Conclusion

The 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 registration

ClinicalTrials.gov identifier no.: NCT01714362

The Oculocardiac Reflex: A Review

BACKGROUND

A typical oculocardiac reflex (OCR) is a moderate trigemino-vagal bradycardia elicited by tension on an extraocular muscle (EOM) during strabismus surgery; however, many other orbital stimuli can elicit cardiac slowing including retinopathy of prematurity examination.

METHODS

World literature related to trigeminovagal and oculocardiac reflex covering over 15,000 patients including 51 randomized clinical trials and case reports are analyzed and reviewed. Under an ongoing observational trial in Alaska, anesthetic, patient and surgical influences on routine strabismus surgery using prospective, uniform EOM tension are compared seeking sufficient sample size to characterize this individually widely variable cardiac response.

RESULTS

With adequate sample size, and emphasizing clinical studies controlling type of EOM, muscle tension amount and duration, anticholinergic and opioid medications, the following augment OCR; rapid-acting opioids and dexmedetomidine while OCR is reduced in older patients, the right eye, less EOM tension, deeper inhaled agents, hypocarbia, anticholinergic medications and orbital block. In re-operations, the former are relatively poor predictors of subsequent OCR.

CONCLUSION

Profound bradycardia can occur in almost 10% of strabismus surgery cases without anticholinergic preventive measures, but reliable prediction of OCR remains elusive. With foreknowledge and careful anesthetic monitoring of the patient before EOM manipulation, residual adverse sequelae from OCR are fortunately very rare. Despite well over a century of experience, the teleology for this occasionally dramatic cardiac response to eye surgery is still not known.