Postoperative Nausea and Vomit in Strabismus Surgery
Condition: Strabismus
MeSH terms: Strabismus; Nausea; Postoperative Nausea and Vomiting
Study type: Observational

Summary: 
      Postoperative nausea and vomiting (PONV) is a major concern in paediatric inpatient surgery
      and may increase patient discomfort, delay patient discharge, and increase the cost of
      patient care. The incidence of PONV after strabismus surgery is relatively high, compared
      with other inpatient surgeries, particularly in children. Oculocardiac reflex (OCR) is a
      phenomenon defined by bradycardia or dysrhythmia during strabismus surgery. Oculocardiac
      reflex is commonly caused by the traction on the extraocular muscle (EOM), which, through the
      ophthalmic branch of trigeminal nerve, stimulates the vagal center. The afferent arm of the
      reflex is the ophthalmic branch of the trigeminal nerve, and the efferent arm is the vagus
      nerve, which diminishes sinoatrial node impulses and leads to bradycardia.While there is a
      general consensus regarding the role of unmodifiable risk factors for PONV, including the
      number of muscle and the occurrence of Oculocardiac reflex or not, the role of modifiable
      risk factors, such as duration of surgery and anesthesia and perioperatively administered
      medications, is still disputed. In the present study, the investigators evaluated whether
      these factors may be associated with postoperative nausea and vomiting after paediatric
      strabismus surgery while controlling for a range of covariates.
    

Detailed description: 
      The primary outcome was incidence of PONV that occurred within 3 days after the operation.
      The investigators defined PONV as a presence of either nausea or vomiting. In study hospital,
      it was routine for nurses to assess and record nausea and vomiting every 8 hours for all
      postoperative patients during postoperative 3 days. Accordingly, the investigators
      retrospectively collected the presence of PONV from electrical medical records. If patients
      had discharged hospital within postoperative 3 days, the incidence of PONV was assessed
      solely during hospital stay. The data, collected included information regarding age at
      surgery, gender, and type of strabismus. During strabismus surgery, the number and sequence
      of the operated muscles, HR before traction of the EOM (baseline HR), maximum decreased HR
      after traction of the EOM, HR at maximum recovery from decreased HR and maintained during
      traction of the EOM (adrenergic HR), and HR at the cutting of the muscle, were collected.
      Oculocardiac reflex was defined as a decrease in HR greater than or equal to 20% rather than
      maximum at first traction of the muscle.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        All patients aged from 2-14 years who underwent strabismus surgery under general anesthesia
        between January 2018 and November 2018 were included in this study. -
      
Keywords: Postoperative nausea and vomiting; strabismus surgery; oculocardiac reflex