AIM AND OBJECTIVES

Aim:

To study effectiveness of Apnoeic oxygenation with low-flow oxygen cannula during intubation in paediatric patients with difficult airway due to large head size caused by Hydrocephalus.

 Primary Objective:

1.     The primary outcome was the incidence of hypoxemia during intubation attempts i.e. fall in  oxygen saturation (SpO₂) to ≤95%.

 Secondary Objectives:

1.     Elapsed time for pulse-oximetry (SpO₂) falling from 100% to 95%.

2.     Incidence of need of restarting face mask ventilation again to prevent hypoxia.

3.     Difficulty during face mask ventilation with nasal cannula in situ.

4.     Head and chest circumference ratio

5.     Other complications

MATERIAL AND METHODS

Study Setting:

This prospective randomized controlled trial will include patients below 1 years, American Society of Anaesthesiologists (ASA) physical status 1 to 3, who will undergo elective or emergency VP shunt surgery under general anaesthesia.

Study Design: 

Prospective single-blind randomized controlled trial

Study Duration:

–     One year

Sample collection –

–     Total 74 cases (37 in each group)

Inclusion Criteria:

–     Known case of Hydrocephalous

–     Age below 1 year

–     Elective or Emergency surgery under general anaesthesia

Exclusion Criteria:

–     Patient not giving consent

–     Difficult airway other than hydrocephalus

Study groups:

Participants will be randomized in to two groups-

1.     Group A- (Apnoeic Oxygenation Group): This group will receive oxygen flow at 5 liter per minute via regular nasal cannula along with face mask ventilation during induction.

2.     Group B- (Conventional induction group): This group will receive only face mask ventilation during induction.

Methodology

Study subjects will be randomized to either the Group-A (Apnoeic Oxygenation Group) or Group-B(Conventional induction group) in 1:1 ratio allocation using computer-generated block size of four randomization by an independent statistician. The random allocation sequence will be kept separately in sealed opaque envelopes with sequential numbers. Blinding is not possible in this study because a nasal cannula will be used for the intervention which will be visible to all.

Upon arrival in the OR, standard monitoring will be applied prior to induction. All participants will be administered with 100% oxygen 5 liters per minute (LPM) using a tight-fitting facemask connected to the Ayes t-piece. Rapid sequence induction of anesthesia will be conducted with fentanyl 2.0mcg/kg and thiopental 5 mg/kg followed by either succinylcholine 1.5 mg/kg or atrauronium0.7 mg/kg. The choice of rapidonset muscle relaxant will be according to anesthesiologist discretion. After induction ventilation will be done via tight-fitting facemask till muscle relaxation was expected to be fully achieved. In the Apnoeic Oxygenation group, a nasal cannula with no oxygen flow will be applied prior to preoxygenation with facemask. Apnoeic Oxygenation will be initiated at 5 l/ min at the end of ventilation with ayres t-piece after muscle relaxant is achieved. In the classical group, a nasal cannula will be not applied, and intubation will be performed without Apnoeic Oxygenation. We will monitor and record any drop in SpO₂ until it reaches the primary endpoint. The primary endpoint is defined as hypoxemia (SpO2 decreased to 95%) or successful intubation. Study participants will be intubated by 3^rd year post graduate or or senior anesthesia residents. In case of desaturation, the procedure will be discontinued as soon as the SpO₂ reached 95%. Rescue procedure comprised jaw thrust and positive pressure ventilation via facemask. Intubation will be then reperformed after the SpO2 increased to 100%.

We will record incidence of hypoxemia during intubation, elapsed time for pulse-oximetry (SpO₂) falling from 100% to 95%, incidence of need of restarting face mask ventilation again to prevent hypoxia, and difficulty during face mask ventilation. We will also record complication like; bradycardia, hypotension, airway injury, and pulmonary aspiration. Sign of regurgitation of gastric content will be recorded.

Statistical analysis:

Data will be entered in Microsoft excel and analyzed using statistical software SPSS version25( Chicago, IL,  USA). Student’s t test will be used to analyze parametric data, while the Mann-Whitney U test will be applied to non-parametric data and Fisher’s test to categorical data. P values < 0.05 will be considered statistically significant.

Sample size

In  previous study, the changes in the median time to desaturation (sec) in Apneic oxygenationwas (29.5 sec) and in conventional induction group was (35.0 sec) and the average population variance (σ2) was 8.43.

2 (Zα/₂ + Z _[1-β])² × σ²

n=

      (μ1�’μ2)²

2 (1.96 + 0.84)² ×8.43

n=

    (35.0-29.5)²

n=36.78

In this study we will enroll 37 patients in each group. Assuming 0.05 level significance (Z_α/2 =1.96), and 80% power (Z _[1-β])=0.84) was 36.84 in each group.

Aroonpruksakul N, Sangsungnern P, Kiatchai T. Apneic oxygenation with low-flow oxygen cannula for rapid sequence induction and intubation in pediatric patients: a randomized-controlled trial. TranslPediatr. 2022 Apr;11(4):427-437. 

REFERENCES

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2.     Tan Z, Lee SY. Pulmonary aspiration under GA: a 13-year audit in a tertiary pediatric unit.PaediatrAnaesth 2016;26:547-52. 1

3.     Aroonpruksakul N, Sangsungnern P, Kiatchai T. Apneic oxygenation with low-flow oxygen cannula for rapid sequence induction and intubation in pediatric patients: a randomized-controlled trial. TranslPediatr. 2022 Apr;11(4):427-437.

4.     Vagyannavar R, Bharti V, Hashim M. Difficult Airway in a Case of Gross Hydrocephalus for Shunt Surgery. Anesth Essays Res. 2017 Oct-Dec;11(4):1109-1111

5.     Napolitano N, Laverriere EK, Craig N, et al. Apneic Oxygenation As a Quality Improvement Intervention in an Academic PICU. PediatrCrit Care Med 2019;20:e531-7. 10.1097/PCC.0000000000002123

6.     Scott A, Chua O, Mitchell W, Vlok R, Melhuish T, White L. Apneic Oxygenation for Pediatric Endotracheal Intubation: A Narrative Review. J Pediatr Intensive Care. 2019 Sep;8(3):117-121.

7.     Soneru CN, Hurt HF, Petersen TR, et al. Apneic nasal oxygenation and safe apnea time during pediatric intubations by learners. PaediatrAnaesth 2019;29:628-34. 10.1111/pan.136451