Hydroxyzine Dihydrochloride Premedication is a Necessity for Strabismus Surgery
Condition: Strabismus; Reflex, Oculocardiac; Hydroxyzine; Bradycardia Sinus
MeSH terms: Strabismus; Bradycardia
Study type: Observational [Patient Registry]

Summary: 
      Oculocardiac reflex (OCR) is usually happening in pediatric strabismus surgery and observed
      just when the surgent pulls the ocular muscles. The reflex is one of the trigemino-vagal
      reflexes, and causes bradycardia, arrhythmia, and even cardiac arrest during eye surgery.

      Premedication for relaxation with drugs like hydroxyzine dihydrochloride or midazolam before
      surgery of the pediatric population is often used in Turkey, although it is not recommended
      in foreign countries. Some recent studies showed that when midazolam and hydroxyzine
      dihydrochloride used together not only, they lessen agitation before surgery but also they
      prevent emergence agitation.

      The primary aim of this prospective observational study is to show the effect of hydroxyzine
      dihydrochloride on preventing the pediatric patient from Oculocardiac reflex related to
      strabismus surgery.
    

Detailed description: 
      Strabismus surgery is a frequently performed surgery in the Turkish population from one year
      of age to adults. Oculocardiac reflex(OCR) is the most recent complication happens during the
      operation, and it occurs approximately 20% to 80% according to its definition, in strabismus
      surgery.

      OCR is defined as the presence of dysrhythmia or a sudden heart rate decreased by 20% after
      traction on the extraocular muscles. OCR is one of the trigemino-vagal reflexes and causes
      bradycardia, arrhythmia and even cardiac arrest during eye surgery. To prevent patients from
      this complication the operator and anesthesiologist must cooperate during the operation
      because the first treatment is to stop traction of the muscle, the second one is to use
      atropine after diagnosing bradycardia.

      Oculocardiac reflex related trials were done for decades; searching for how and when it
      happens, which ocular muscles are related mostly, or which patients are at risk of OCR( age,
      heart rate related) are the most researched ones. According to our knowledge, there is no
      research about a premedication to prevent OCR during strabismus surgery.

      Before this study has planned by the investigator, the investigator had seen many OCR
      occurrence related to strabismus surgery, treated either with pausing the surgery or with
      atropin intravenous utilization in other clinics. After started working in this university
      hospital the investigator recognized those pediatric patients whom premedicated do not need
      to treat in the strabismus surgery because the OCR incidence was decreased dramatically. The
      investigator has planned this observational research at Yeditepe University Hospital because
      in this hospital pediatric patients receive variable oral premedication for sedation before
      surgery and for the prevention of emerging agitation. In Yeditepe University Hospital oral
      premedication( with variable drugs and variable doses) is nearly always ordered by
      anesthesiologists unless there is a comorbidity or allergy anamnesis related to the drugs
      planning to use.

      This current study is planned as observational. The investigator does not allow to give any
      orders about premedications or treatments before or during strabismus surgery. The Induction
      and the maintenance of anesthesia are also variable because there is no intervening to the
      anesthetist who performs anesthesia. The anesthetist who orders the premedication and
      performs anesthesia during strabismus surgery is not related to the trial and do not know the
      aim of the trial.

      The investigator is informed about the surgery on the day of the operation. The investigator
      and the patient's encounter before the study are about having the written consent form after
      explanation of the study. The only time to discriminate the patient from the study, by the
      anamnesis of the patient that is taken (about any comorbidities) during the encounter,
      according to the trials eligibility criteria if the patient and the patient has approved for
      including the trial. The investigator has even no permission to access the demographic data
      of the patient from the clinical papers which nurses have prepared because the investigator
      is not the anesthesiologist of the patient. Therefore the demographic data of the patient and
      the premedication performed to the patient is recorded after the operation retrospectively as
      the ethical committee approved. So, this current trial is not randomized, and there is no
      placebo group also, as a control group which is needed for an interventional one. Patients
      included to this trial were grouped after the end of the operation according to the
      premedication utilized, while the patient is awake in the service room after the operation,
      by having permission to access the demographic data and the premedication that had utilized
      before operation retrospectively.

      The prospective part of this study is planned to perform in the operation theatre
      observationally without knowing which premedication is utilized to the patient. In the
      operation theatre, the investigator observes the patient coming to the operation theatre and
      records the patients Ramsey Sedation Score before the operation starts. The heart rate 1, the
      heart rate 2 and the heart rate 3 data are planned to be recorded from the EKG monitorisation
      of the patient; in cooperation with the operator( the operator warns the investigator before
      the traction of the orbital muscle and informs about the name of the orbital muscle.). The
      investigator calculates the difference between the heart rate3 and heart rate2 and records if
      OCR occurred or not. If OCR occurred, the investigator observes and records how it is treated
      by the anesthesiologist in the operation theatre and the orbital muscle name which OCR
      occurred during its traction. The investigator is also not allowed to order any treatment
      about OCR during the operation. Because it is hard to plan this kind of an observational
      study the investigator had two years of paperwork to explain the planning of this
      observational study to be approved from both "Yeditepe University Clinical Trials Ethical
      Committee," and from "The Turkish Ministry of health, Turkish Medicines and Medical Devices
      Agency." A medical doctor from another clinic is charged with the monitorisation of this
      clinical trial by the ethical committee of the Yeditepe University whose identity is not
      known by the investigator.

      The primary aim of this prospective observational trial is to compare three different
      premedication methods observationally, to see if there is any difference in the OCR
      occurrence in strabismus surgery. The secondary aim is to compare the Ramsey Sedation Scores
      of the patients before surgery, the heart rates during the operation and their effect on OCR.

      The hypothesis is that; the pediatric patients premedicated with hydroxyzine dihydrochloride
      would be prevented from OCR during strabismus surgery because of the drug's side-effect of
      tachycardia while they are sedated before surgery as a positive effect.
    

Intervention name(s): Midazolam; Hydroxyzine Dihydrochloride
Intervention type(s): Drug; Drug
Intervention description(s): Demizolam 15mg/ml ampules, given orally with cherry juice; Atarax 2mg/ml syrup, given orally
Other intervention name(s): Dormicum,8699505751689,N05CD08; Demizolam,8699769750077,N05CD08; Zolamide,8680184750025,N05CD08; ATARAX 200 ml syrup,8699624570062,N05BB01; VALIDOL,8699705590019,N05BB01
Intervention MeSH terms: Midazolam; Hydroxyzine
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Pediatric patients aged between 1 to 10 years who are diagnosed as strabismus or esotropia,
        and scheduled for strabismus surgery.
      
Keywords: Strabismus surgery; Oculocardiac reflex; Hydroxyzine dihydrochloride; Midazolam; Premedication; The Ramsay Scale