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The oculorespiratory reflex revisited
Insights
The oculorespiratory reflex (ORR) consistently occurred during strabismus surgery in children, causing respiratory changes. Controlled ventilation is recommended to prevent potential complications like hypercapnia and hypoxemia.
Area of Science:
- Anesthesiology
- Pediatric Surgery
- Respiratory Physiology
Background:
- The oculorespiratory reflex (ORR) is a known physiological response.
- Strabismus surgery involves eye muscle manipulation, a potential trigger for ORR.
- Monitoring respiratory parameters is crucial during pediatric anesthesia.
Purpose of the Study:
- To investigate the incidence and characteristics of the oculorespiratory reflex (ORR) during strabismus surgery in children.
- To assess the impact of ORR on respiratory parameters.
- To evaluate the effectiveness of atropine in modulating the ORR.
Main Methods:
- Continuous monitoring of intratracheal pressure and capnography in eight children (5-14 years) undergoing strabismus surgery.
- Evoking the ORR through traction on extrinsic eye muscles.
- Administering intravenous atropine to assess its effect on ORR incidence.
Main Results:
- The oculorespiratory reflex (ORR) was observed in 100% of patients, manifesting as slowed or shallow breathing.
- One patient experienced a 20-second apneic episode requiring manual ventilation.
- Atropine reduced the incidence of oculocardiac reflex (OCR) but not the ORR.
Conclusions:
- Oculorespiratory reflex (ORR) is a consistent finding during strabismus surgery in children.
- ORR can lead to respiratory compromise, including hypercapnia and hypoxemia.
- Controlled ventilation is recommended during eye muscle traction in strabismus surgery to mitigate risks.
Abstract:
Continuous measurement of the intratracheal pressure and capnography are very simple and accessible methods for the detection and recording of the oculorespiratory reflex (ORR). Eight healthy children (five to 14 years old) undergoing strabismus surgery under halothane-nitrous oxide anaesthesia with spontaneous ventilation were studied. The ORR was evoked by traction on the extrinsic muscles of the eye (four medial recti and four lateral recti). Slowing of the respiratory rate and/or shallow respiratory movements were observed in each patient. One patient developed apnoea of 20 seconds duration which forced the use of manually controlled ventilation. Intravenous atropine (0.01 mg.kg-1) reduced the incidence of positive OCR (to 37.5 per cent) but did not diminish the incidence of the ORR (100 per cent). Since the ORR may lead to hypercapnia and hypoxaemia, controlled ventilation is recommended for patients undergoing strabismus surgery at least immediately before and during the muscular traction. It is now clear that the ORR may be evoked by traction on the extrinsic muscles of the eye, may produce hypercapnia and hypoxaemia and so, may aggravate the consequences of the OCR.