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

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.

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.

Patients will spontaneously ventilated. Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane.

Patients will be mechanically ventilated without muscle relaxation.Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane.

Patients will be mechanically ventilated with muscle relaxation.Laryngeal mask airway will be inserted and anesthesia is maintained with sevoflurane.

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.

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.

Capnography connected to laryngeal mask airway is introduced after adequate jaw relaxation; its size is chosen according to the body weight of the child.

Sevoflurane in air/oxygen mixture of 40% will be titrated to achieve adequate depth of anesthesia to maintain immobilization of the eye.

Dynamic compliance (ml /cm H2O) will be recorded after stabilization of ventilation and at the end of surgery

The ophthalmogist will be investigated postoperatively for the quality of surgical field (0-8; 0=None, 8=total satisfaction)

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)

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.

Dias R, Dave N, Agrawal B, Baghele A. Correlation between bispectral index, end-tidal anaesthetic gas concentration and difference in inspired-end-tidal oxygen concentration as measures of anaesthetic depth in paediatric patients posted for short surgical procedures. Indian J Anaesth. 2019 Apr;63(4):277-283. doi: 10.4103/ija.IJA_653_18.

Fudickar A, Gruenewald M, Fudickar B, Hill M, Wallenfang M, Hullemann J, Voss D, Caliebe A, Roider JB, Steinfath M, Treumer F. Immobilization during anesthesia for vitrectomy using a laryngeal mask without neuromuscular blockade versus endotracheal intubation and neuromuscular blockade. Minerva Anestesiol. 2018 Jul;84(7):820-828. doi: 10.23736/S0375-9393.17.12282-0. Epub 2017 Oct 12.

Ghabach MB, El Hajj EM, El Dib RD, Rkaiby JM, Matta MS, Helou MR. Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee. Anesth Essays Res. 2017 Jan-Mar;11(1):197-200. doi: 10.4103/0259-1162.200238.

Lewis SR, Pritchard MW, Fawcett LJ, Punjasawadwong Y. Bispectral index for improving intraoperative awareness and early postoperative recovery in adults. Cochrane Database Syst Rev. 2019 Sep 26;9(9):CD003843. doi: 10.1002/14651858.CD003843.pub4.

Waldschmidt B, Gordon N. Anesthesia for pediatric ophthalmologic surgery. J AAPOS. 2019 Jun;23(3):127-131. doi: 10.1016/j.jaapos.2018.10.017. Epub 2019 Apr 14.

Singh PM, Trikha A, Sinha R, Borle A. Measurement of consumption of sevoflurane for short pediatric anesthetic procedures: Comparison between Dion's method and Dragger algorithm. J Anaesthesiol Clin Pharmacol. 2013 Oct;29(4):516-20. doi: 10.4103/0970-9185.119160.

Mason KP. Paediatric emergence delirium: a comprehensive review and interpretation of the literature. Br J Anaesth. 2017 Mar 1;118(3):335-343. doi: 10.1093/bja/aew477.