Intravenous versus inhalational anesthesia for pediatric inpatient surgery - A systematic review and meta-analysis

Analysis of influencing factors and construction of prediction model for postoperative nausea and vomiting in patients undergoing laparoscopic sleeve gastrectomy: a single-center retrospective cohort study

BACKGROUND

With the increasing number of bariatric surgeries, the high incidence of postoperative nausea and vomiting (PONV) associated with this surgery has also gradually attracted attention. Among the common bariatric surgery methods, patients undergoing sleeve gastrectomy (SG) have the highest incidence of nausea and vomiting. The mechanism of occurrence of PONV is very complex. This study aims to explore the influencing factors of PONV in patients undergoing laparoscopic sleeve gastrectomy (LSG) and construct a nomogram prediction model based on these factors.

METHODS

With the approval of the Ethics Committee, the electronic medical records of patients who underwent LSG from July 2022 to May 2023 were collected retrospectively.

RESULTS

A total of 114 patients with complete medical records who underwent LSG from July 2022 to May 2023 were included in this study. Among them, 46 patients developed PONV, resulting in a PONV incidence rate of 40.4%. Multivariate logistic regression analysis revealed that female gender, the use of inhalation anesthesia, and operation time ≥ 120 min were risk factors for PONV in LSG. Additionally, the use of more than two kinds of antiemetic drugs was identified as a protective factor. Based on these factors, a nomogram model was constructed.

CONCLUSION

PONV in patients undergoing LSG is related to gender, type of anesthesia, duration of surgery, and combination therapy with antiemetic drugs. The nomogram prediction model constructed in this study demonstrates high accuracy and discrimination in predicting the occurrence of PONV in patients undergoing LSG.

Nanotherapeutics for Alleviating Anesthesia-Associated Complications

Current management of anesthesia-associated complications falls short in terms of both efficacy and safety. Nanomaterials with versatile properties and unique nano-bio interactions hold substantial promise as therapeutics for addressing these complications. This review conducts a thorough examination of the existing nanotherapeutics and highlights the strategies for developing prospective nanomedicines to mitigate anesthetics-related toxicity. Initially, general, regional, and local anesthesia along with the commonly used anesthetics and related prevalent side effects are introduced. Furthermore, employing nanotechnology to prevent and alleviate the complications of anesthetics is systematically demonstrated from three aspects, that is, developing 1) safe nano-formulization for anesthetics; 2) nano-antidotes to sequester overdosed anesthetics and alter their pharmacokinetics; 3) nanomedicines with pharmacodynamic activities to treat anesthetics toxicity. Finally, the prospects and challenges facing the clinical translation of nanotherapeutics for anesthesia-related complications are discussed. This work provides a comprehensive roadmap for developing effective nanotherapeutics to prevent and mitigate anesthesia-associated toxicity, which can potentially revolutionize the management of anesthesia complications.

Comparing Perioperative Outcomes of Total Intravenous Anesthesia (TIVA) With Volatile Anesthesia in Patients With Obesity: A Systematic Review

In this systematic review, the perioperative outcomes of total intravenous anesthesia (TIVA) and volatile anesthesia were compared in obese adults (BMI ≥ 30 kg/m²) undergoing elective surgery. The review analyzed data from 12 randomized-controlled trials involving 935 patients, sourced from PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Cochrane, Scopus, and Web of Science databases. The focus was on intraoperative vital signs, emergence time, postoperative nausea and vomiting (PONV), duration of post-anesthesia care unit (PACU) stay, and ICU admission rates. Findings showed that TIVA (using propofol) might reduce PONV, but there were no significant differences in other outcomes compared to volatile anesthesia (with desflurane as the most common agent). The review highlights the need for more research, especially comparing sevoflurane with TIVA, to establish clear clinical guidelines for anesthesia in obese patients.

Is PONV still a problem in pediatric surgery: a prospective study of what children tell us

Background

Postoperative nausea and vomiting (PONV) is an unpleasant complication after surgery that commonly co-occurs with pain. Considering the high prevalence among pediatric patients, it is important to explore the main risk factors leading to PONV in order to optimize treatment strategies. The objectives of this study are as follows: (1) to determine the prevalence of PONV on the day of surgery by conducting interviews with pediatric patients, (2) to assess PONV prevalence in the recovery room and on the ward by analyzing nursing records, and (3) to collect information on PONV risk factors on the day of surgery and the following postoperative days. We wanted to investigate real-life scenarios rather than relying on artificially designed studies.

Methods

A prospective analysis [according to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines] of PONV on the day of surgery and the following postoperative days was conducted by evaluating demographic and procedural parameters, as well as conducting interviews with the children under study. A total of 626 children and adolescents, ranging in age from 4 to 18 years, were interviewed on the ward following their surgery. The interviews were conducted using a questionnaire, as children aged 4 and above can participate in an outcome-based survey.

Results

On the day of surgery, several multivariable independent predictors were identified for PONV. The type of surgery was found to be a significant factor (p = 0.040) with the highest odds ratio (OR) in patients with procedural investigations [OR 5.9, 95% confidence interval (CI): 1.8-19.2], followed by abdominal surgery (OR 3.1, 95% CI: 0.9-11.1) when inguinal surgery was used as the reference category. In addition, the study identified several predictors, including the amount of fentanyl administered during anesthesia (µg/kg body weight) (OR 1.4, 95% CI: 1.1-1.8), intraoperative use of piritramide (OR 2.6, 95% CI: 1.5-4.4) and diclofenac (OR 2.0, 95% CI: 1. 3-3.1), opioid administration in the recovery room (OR 3.0, 95% CI: 1.9-4.7), and piritramide use on the ward (OR 4.5, 95% CI: 1.7-11.6).

Conclusions

The main risk factors for PONV include the intraoperative administration of opioids during the recovery room stay and at the ward, the intraoperative use of non-opioids (diclofenac), and the specific type of surgical procedure. Real-life data demonstrated that in clinical praxis, there is a gap between the adherence to established guidelines and the use of antiemetic prophylaxis in surgeries that are generally not associated with a high PONV prevalence. Further efforts are needed to improve the existing procedures and thus improve the overall outcome.

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

Profound trigeminocardiac reflex from lingual nerve stimulation: a case report

Trigeminocardiac reflex (TCR) is a well-known brainstem reflex that manifests as hypotension, bradycardia, dysrhythmia, and asystole when stimulation is applied to a branch of the trigeminal nerve. Most commonly associated with ophthalmic, orbital, and neurologic surgeries, mandibular division and oral cavity variants occur far less frequently. Here, we describe a case of asystolic TCR elicited by lingual nerve stimulation. This case highlights the role of specific anesthetic medications in modulating this phenomenon and reinforces the need for early recognition and clear communication in case of its occurrence. Anesthesia providers must consider discontinuing or avoiding certain medications when clinically appropriate, even during low TCR-risk procedures.

Why a Propofol Infusion Should Be the Anesthetic of Choice for Auditory Brainstem Response Testing in Children

BACKGROUND

Auditory brainstem response (ABR) testing is considered to be relatively resistant to effects of volatile anesthetics. The impact of newer anesthetics on interpretability of ABR testing is unknown. This study compared sevoflurane versus propofol anesthesia on qualitative interpretability of ABR click-testing in children.

METHODS

This prospective double-blind crossover study enrolled children (≤18 years old) receiving general anesthesia for elective ABR testing. All subjects received both sevoflurane and propofol anesthesias in the same ABR testing session. Deidentified ABR data were reviewed by 5 audiologists (blinded to anesthetic and patient) to determine threshold levels for hearing loss. The primary outcome was qualitative interpretability (false positive) of ABR click-testing.

RESULTS

Each patient was tested at 4 different intensities in each ear: generating 624 records under each anesthetic, for a total of 1248 records. A few patients were tested at 5 different intensities in a single ear accounting for the additional 11 records, yielding 1259 records. Under sevoflurane anesthesia, 21 of the same patients (37 ears) were identified with abnormal ABR levels consistent with hearing loss (one or both ears). The probability of a patient being diagnosed with hearing "loss" in one or both ears was significantly less with propofol versus sevoflurane anesthesia (mid P =.0312). If patients with bilateral loss are compared, the mid P value is 0.0098. The effect size based on patients was medium to large, with a minimum value of Cohen w = 0.320.

CONCLUSIONS

Sevoflurane produced more false positives for hearing loss and suggested more severe hearing loss than propofol. False-positive ABR tests, produced by certain anesthetic agents, can have significant life-long impact and negative psychosocial and developmental implications. Use of the intravenous anesthetic propofol is superior to sevoflurane for ABR testing in children.

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.

[Inhalational anesthetics]

Inhalational anesthetics have been used for induction and maintenance of general anesthesia for more than 150 years. All of the currently used inhalational anesthetics are chlorinated and fluorinated derivatives of ether. Dosing is carried out using the minimal alveolar concentration (MAC) concept. The pharmacokinetic properties of the various inhalational anesthetics are governed by the specific distribution coefficients. Mechanisms of action include specific modulations of various receptors of the central nervous system as well as an unspecific interaction with the cell membrane. Organ toxicity of modern inhalational anesthetics is considered to be minimal. The role of inhalational anesthetics in the context of postoperative nausea and vomiting (PONV) has been reassessed in recent years. The superiority of inhalational anesthetics over intravenous hypnotics with respect to intraoperative awareness is undisputed. The organ protective mechanism of preconditioning is an exclusive property of inhalational anesthetics among all the currently available hypnotics.

Effect of general inhalational anesthesia on intraocular pressure measurements in normal and glaucomatous children

PURPOSE

To investigate the agreement between the intraocular pressure (IOP) measurements in the awake condition and under different stages of general inhalational anesthesia using sevoflurane in both glaucomatous and normal children.

METHODS

A prospective study was performed on 43 glaucomatous children and 30 age-matched controls. Baseline IOP of one eye was measured immediately before general anesthesia using Perkins tonometer and then re-measured under light, intermediate, and deep anesthesia, and then after intubation. Depth of anesthesia was determined using bispectral index pediatric sensor. The agreement between the IOP measurements before and during different stages of anesthesia was analyzed using Bland-Altman plots. Systematic and proportionate deviations between the IOP measurements were analyzed.

RESULTS

The mean age was 58.6 ± 41.99 months. The mean IOP was significantly lower at all stages of anesthesia in both groups. The coefficient of variation was over 20% in all measurements under anesthesia. For all IOP measurements during anesthesia, the limits of agreement were > 7 mmHg difference in the control group and > 20 mmHg in the glaucomatous group. The best agreement was with the IOP measurement after intubation (mean limit of agreement of -1.4 mmHg, 1.96 s range, -8.8-6 mm Hg) in the control group and with the IOP measurement under intermediate anesthesia (mean limit of agreement of -4.2 mmHg, 1.96 s range, -15.1-6.8 mm Hg) in the glaucomatous group.

CONCLUSIONS

Inhalational anesthesia has variable effects on IOP measurement at all stages of anesthesia. Caution should be taken when extrapolating the true IOP from these measurements.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Penehyclidine mitigates postoperative nausea and vomiting and intraoperative oculocardiac reflex in patients undergoing strabismus surgery: a prospective, randomized, double-blind comparison

Background

Postoperative nausea and vomiting (PONV) is one of the most frequent complications following strabismus surgery. Penehyclidine, an anticholinergic agent, is widely used as premedication. This study investigated the effect of preoperative penehyclidine on PONV in patients undergoing strabismus surgery.

Methods

In this prospective, randomized, double-blind study, patients scheduled for strabismus surgery under general anesthesia were randomly assigned to either penehyclidine (n = 114) or normal saline (n = 104) group. Penehyclidine was administrated immediately after anesthesia induction, and normal saline was substituted as control. PONV was investigated from 0 to 48 h after surgery. Intraoperative oculocardiac reflex (OCR) was also recorded.

Results

Compared with normal saline, penehyclidine significantly reduced PONV incidence (30.7% vs. 54.8%, P < 0.01) and mitigated PONV severity as indicated by severity scoring (P < 0.01). Compared with normal saline, penehyclidine also significantly reduced OCR incidence (57.9% vs. 77.9%, P < 0.01) and mitigated OCR severity, as indicated by the requirement for atropine rescue (77.3% vs. 90.1%, P < 0.05) and the maximum decrease of heart rate during OCR (23.1 ± 9.4 bpm vs. 27.3 ± 12.4 bpm, P < 0.05). The recovery course did not differ between groups.

Conclusions

Penehyclidine administrated after anesthesia induction significantly reduced the incidence of PONV and alleviated intraoperative OCR in patients undergoing strabismus surgery.

Trial registration

ClinicalTrials.gov (NCT04054479). Retrospectively registered August 13, 2019.

Postoperative Nausea and Vomiting in Pediatric Patients

Postoperative nausea and vomiting (PONV), postoperative vomiting (POV), post-discharge nausea and vomiting (PDNV), and opioid-induced nausea and vomiting (OINV) continue to be causes of pediatric morbidity, delay in discharge, and unplanned hospital admission. Research on the pathophysiology, risk assessment, and therapy for PDNV, OINV and pain therapy options in children has received increased attention. Multimodal pain management with the use of perioperative regional and opioid-sparing analgesia has helped decrease nausea and vomiting. Two common emetogenic surgical procedures in children are adenotonsillectomy and strabismus repair. Although PONV risk factors differ between adults and children, the approach to decrease baseline risk is similar. As PONV and POV are frequent in children, antiemetic prophylaxis should be considered for those at risk. A multimodal approach for antiemetic and pain therapy involves preoperative risk evaluation and stratification, antiemetic prophylaxis, and pain management with opioid-sparing medications and regional anesthesia. Useful antiemetics include dexamethasone and serotonin 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron. Multimodal combination prophylactic therapy using two or three antiemetics from different drug classes and propofol total intravenous anesthesia should be considered for children at high PONV risk. "Enhanced recovery after surgery" protocols include a multimodal approach with preoperative preparation, adequate intravenous fluid hydration, opioid-sparing analgesia, and prophylactic antiemetics. PONV guidelines and management algorithms help provide effective postoperative care for pediatric patients.

The Impact of Re-Operation, Relatives and Race on the Oculocardiac Reflex During Strabismus Surgery

Purpose

The oculocardiac reflex (OCR) is a trigeminovagal bradycardia elicited by tension on an extraocular muscle (EOM). Using three decades of observational data, we investigated whether or not individual strabismus patients are prone to oculocardiac reflex.

Patients and Methods

All patients undergoing strabismus surgery from 1992 to 2019 had deliberate 10-second, 200-gram square-wave tension on extraocular rectus muscles with anesthetic variables recorded. OCR was defined as the maximally tension-altered heart rate as a percent of stable baseline heart rate.

Results

OCR was compared in 2532 original cases with 323 re-operations. The 169 cases that used anticholinergics (99% OCR) were excluded from the analysis. The median OCR, a 15% drop, was found to be 85% (95% CI 39%, 102%,; range 5–151%). Factors that showed a significant effect on the OCR were the type of EOM with lateral rectus least (Kruskal–Wallis X²(3)=8, p<0.05), and adults had less OCR compared to the children (X²(2)=105, p<0.01). Factors that showed an augmenting effect on the OCR were peri-operative opioids (X²(6)=62, p<0.01) and Caucasian race (X²(4)=12, p<0.02). Gender and iris color were not found to have an impact on OCR. Re-operations and first-degree relatives did not differ from age-matched controls, but EOM- and opioid-adjusted re-operations correlated with their initial cases (r=0.37).

Conclusion

We confirmed the previously published blocking effect of atropine, augmenting impact of opioids, and an inverse relationship of age on OCR. There was a weak proclivity for individuals to be prone to OCR. We found an impact of race with Caucasians having more OCR.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/QQ9RJ41sHFI

Intravenous cannula placement in children for induction of general anesthesia: Prospective audit and identification of success factors

BACKGROUND

Approaches to pediatric induction of anesthesia vary widely. While oral sedative premedication and inhalational induction are common, total intravenous anesthesia is becoming increasingly popular. Total intravenous anesthesia without anxiolytic premedication, which is the most commonly used technique in our hospital, requires intravenous (IV) cannula placement in an awake child.

AIMS

To quantify the success rate of IV cannula placement in 1 or 2 attempts and to identify success factors and barriers.

METHODS

With ethical approval and written informed consent from participating anesthesiologists, a prospective audit of IV cannulation was undertaken over a 1-month period. The attending anesthesiologist captured basic demographics, IV insertion characteristics, setting, distraction techniques, the behavior of the child, number of attempts, and success/failure. A logistic regression model for successful IV cannulation was created. Anesthesiologists and procedural suite nurses participated in semi-structured interviews to identify success factors, barriers, and teaching approaches.

RESULTS

Data from 984 cases were analyzed. IV induction was planned in 562 cases, and IV cannulation was successful in 90% of these patients. Anxiolytic premedication was given in 6% of cases. Observations indicated that 64% of children were pain- and reaction-free, and 90% experienced minimal or no reaction. Predictors for success included older child's age and child behavior at first encounter. Qualitative interview data from 13 participants suggested success factors included effective distraction, preparing the family for IV induction, parental presence, support of the operating room team, effective use of local analgesic cream, adapting the approach to the individual child, and the anesthesiologist's efficiency. Barriers included needle phobia, uncooperative child, anxious parents, ineffective use of analgesic cream, and unfavorable anatomy. Distraction techniques varied by age and developmental stage of the child.

CONCLUSIONS

Cannulation for planned IV induction is feasible for most children, enabling increased use of total intravenous anesthesia as an institutional anesthetic strategy.

General Anesthesia Maintained with Sevoflurane versus Propofol in Pediatric Surgery Shorter Than 1 Hour: A Randomized Single-Blind Study

Background

Sevoflurane was compared with propofol for general anesthesia maintenance in pediatric operations lasting less than 1 hour in terms of anesthetic effect and postoperative recovery.

Material/Methods

Children scheduled for inguinal hernia repair or hydrocele testis repair were randomly assigned to receive general anesthesia maintained with either sevoflurane (n=43) or propofol (n=43). The ilioinguinal nerve was blocked with 1% lidocaine (7 mg/kg) after intravenous administration of ketamine (2 mg/kg). At the end of the surgery in patients receiving sevoflurane, sevoflurane was stopped and a bolus of propofol of 1 mg/kg was administered.

Results

Sevoflurane was associated with significantly less use of ketamine (35.1±10.6 mg) than was propofol (59.0±28.0 mg; P<0.001). In addition, sevoflurane was associated with a significantly shorter time in the post-anesthesia care unit (52.1±9.0 min) than was propofol (68.8±15.3 min; P<0.001). Propofol was associated with a significantly higher incidence of intraoperative body movement (33.3%) than was sevoflurane (13.5%; P=0.045). However, the 2 groups showed no important differences in other adverse events such as hypoxia, emergence agitation, and additional use of propofol.

Conclusions

In pediatric surgery lasting less than 1 hour, anesthesia maintained with sevoflurane was associated with significantly less use of ketamine, shorter postoperative recovery time, and less intraoperative body movement than was propofol.

Propofol use in newborns and children: is it safe? A systematic review

OBJECTIVES

To determine the main indications and assess the most common adverse events with the administration of hypnotic propofol in most pediatric clinical scenarios.

SOURCES

A systematic review of PubMed, SciELO, Cochrane, and EMBASE was performed, using filters such as a maximum of five years post-publication, and/or references or articles of importance, with emphasis on clinical trials using propofol. All articles of major relevance were blind-reviewed by both authors according to the PRISMA statement, looking for possible bias and limitations or the quality of the articles.

SUMMARY OF THE FINDINGS

Through the search criterion applied, 417 articles were found, and their abstracts evaluated. A total of 69 papers were thoroughly studied. Articles about propofol use in children are increasing, including in neonates, with the majority being cohort studies and clinical trials in two main scenarios: upper digestive endoscopy and magnetic resonance imaging. A huge list of adverse events has been published, but most articles considered them of low risk.

CONCLUSIONS

Propofol is a hypnotic drug with a safe profile of efficacy and adverse events. Indeed, when administered by non-anesthesiologists, quick access to emergency care must be provided, especially in airway events. The use of propofol in other scenarios must be better studied, aiming to reduce the limitations of its administration by general pediatricians.

The oculocardiac reflex and depth of anesthesia measured by brain wave

Background

The 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.

Methods

In 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.

Results

From 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%).

Conclusions

We 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 registry

NCT03663413.

Data: http://www.abcd-vision.org/OCR/OCR%20Brainwave%20de-identified.pdf.