Impact of Different Modes of Ventilation With Laryngeal Mask Airway on Pediatric Cataract Surgery

Study Overview
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Brief Summary
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This study will be conducted to evaluate effects of different modes of ventilation on pediatric cataract surgery aiming to a peri-operative stable anesthesia, better surgical satisfaction and post operative recovery. It is hypothesized that controlled ventilation without muscle relaxation will be advantageous to other modes in providing adequate surgical satisfaction with considerable depth of anesthesia and better recovery profile.

Detailed Description
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Anesthetic management in pediatric cataract surgery constitutes a special challenge. Any eye movements can lead to an unsatisfactory surgical field and increase the risk of ophthalmological complications. Achieving adequate ventilation of children is considered another challenge due to huge variability in size and lung maturity. Spontaneous breathing is a popular mode of ventilation with several beneficial effects. Controlled ventilation without muscle relaxation using laryngeal mask airway is attractive option because the side effects of muscle relaxants are avoided. Therefore, this study will be conducted to evaluate effects of different modes of ventilation on pediatric cataract surgery aiming to a peri-operative stable anesthesia, better surgical satisfaction and post-operative recovery. This prospective, randomized, comparative clinical study will include 150 children who will be scheduled for elective cataract surgery under general anesthesia in Mansoura ophthalmology center over one year. Informed written consent will be obtained from parents of all subjects in the study after ensuring confidentiality.The study protocol will be explained to parents of all patients in the study who will be kept fasting prior to surgery. Patients will be randomly assigned to three equal groups according to computer-generated table of random numbers using the permuted block randomization method. In the first group, spontaneous ventilation will be maintained with pressure support; while in the two other groups, mechanical ventilation will be applied with pressure controlled modes. The collected data will be coded, processed, and analyzed using SPSS program. All data will be considered statistically significant if P value is ≤ 0.05.

Official Title
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Impact of Different Modes of Ventilation With Laryngeal Mask Airway on Pediatric Cataract Surgery

Conditions
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Ventilation, Laryngeal Mask Airway, Cataract Surgery

Intervention / Treatment
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* Procedure: Pressure Support Ventilation
* Procedure: Unparalyzed Pressure Control Ventilation
* Procedure: Paralyzed Pressure Control Ventilation
* Device: Laryngeal Mask Airway
* Drug: Sevoflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiology (ASA) I and II patients. Scheduled for elective cataract surgery. Exclusion Criteria: Parental refusal of consent. Contraindication to use of supraglottic airway device as gastroesophageal reflux and oropharyngeal pathology. Hyperactive airway disease or respiratory diseases. Children with developmental delays, mental or neurological disorders. Bleeding or coagulation diathesis. History of known sensitivity to the used anesthetics. Previous surgery in the same eye.

Ages Eligible for Study
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Minimum Age: 1 Year
Maximum Age: 5 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Spontaneous Ventilation<br>Patients will spontaneously ventilated. Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane. | Procedure: Pressure Support Ventilation<br>* Ventilator will be adjusted to administer pressure at 10 cmH2O.<br>* Other names: Assisted Ventilation;Device: Laryngeal Mask Airway<br>* Capnography connected to laryngeal mask airway is introduced after adequate jaw relaxation; its size is chosen according to the body weight of the child.<br>* Other names: Supraglottic Airway Device;Drug: Sevoflurane<br>* Sevoflurane in air/oxygen mixture of 40% will be titrated to achieve adequate depth of anesthesia to maintain immobilization of the eye.<br>* Other names: Inhalational Anesthesia;|
| Active Comparator: Unparalyzed Controlled Ventilation<br>Patients will be mechanically ventilated without muscle relaxation.Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane. | Procedure: Unparalyzed Pressure Control Ventilation<br>* Pressure controlled ventilation mode will be applied to obtain a volume of 8 ml/kg up to 20 cmH2O. The set respiratory rate will be 15 breaths/min then it is adjusted to achieve the end tidal CO2 levels between 35 and 40 mmHg as measured by capnography.<br>* Other names: Positive pressure Ventilation;Device: Laryngeal Mask Airway<br>* Capnography connected to laryngeal mask airway is introduced after adequate jaw relaxation; its size is chosen according to the body weight of the child.<br>* Other names: Supraglottic Airway Device;Drug: Sevoflurane<br>* Sevoflurane in air/oxygen mixture of 40% will be titrated to achieve adequate depth of anesthesia to maintain immobilization of the eye.<br>* Other names: Inhalational Anesthesia;|
| Active Comparator: Paralyzed Controlled Ventilation<br>Patients will be mechanically ventilated with muscle relaxation.Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane. | Procedure: Paralyzed Pressure Control Ventilation<br>* Pressure controlled ventilation mode will be applied to obtain a volume of 8 ml/kg up to 20 cmH2O. The set respiratory rate will be 15 breaths/min then it is adjusted to achieve the end tidal CO2 levels between 35 and 40 mmHg as measured by capnography. Also, neuromuscular blockade will be achieved.<br>* Other names: Positive pressure Ventilation;Device: Laryngeal Mask Airway<br>* Capnography connected to laryngeal mask airway is introduced after adequate jaw relaxation; its size is chosen according to the body weight of the child.<br>* Other names: Supraglottic Airway Device;Drug: Sevoflurane<br>* Sevoflurane in air/oxygen mixture of 40% will be titrated to achieve adequate depth of anesthesia to maintain immobilization of the eye.<br>* Other names: Inhalational Anesthesia;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of eye movements | Incidence any upward or downward deviation of the vision axis during surgery will be recorded | Up to the end of the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in intraocular pressure | Intraocular pressure will be measured (mmHg) in the non-operative eye using Schioetz-Tonometer | Up to the end of the surgery | 
| Changes in bispectral index | Bispectral index values (0-100) will be recorded every five minutes until the end of the surgery | Up to the end of the surgery | 
| Amount of consumption of sevoflurane | Sevoflurane consumption in milliliters will be measured and recorded | Up to the end of the surgery | 
| Changes in dynamic compliance | Dynamic compliance (ml /cm H2O) will be recorded after stabilization of ventilation and at the end of surgery | Up to the end of the surgery | 
| Changes in heart rate | Heart rate (beat/min) will be recorded at five-minute intervals until the end of the surgery | Up to the end of the surgery | 
| Changes in mean arterial blood pressure | Blood pressure (mmHg) will be recorded at five-minute intervals until the end of the surgery | Up to the end of the surgery | 
| Value of surgeon satisfaction from the procedure | The ophthalmogist will be investigated postoperatively for the quality of surgical field (0-8; 0=None, 8=total satisfaction) | After the end of the surgery | 
| Improvement in postoperative emergence agitation scale | Agitation will be assessed using the 5- step Cravero scale (1-5) every five minutes from awakening and for 30 minutes. (1:Obtunded with no response to stimulation, 2:Asleep but responsive to movement or stimulation, 3:Awake and responsive, 4:Crying, 5:Thrashing behaviour that requires restraint) | Up to 30 minutes after surgery |