the Efficacy and Performance of the Pediatric I-gel Mask Clinical Trial
Official title:
Application of I-gel Laryngeal Mask Airway in Infants and Children Undergoing Surgical Procedures
Background The laryngeal mask airway (LMA) is a supraglottic airway device ,which is commonly
used to manage children's airways, because it is typically easy to use and can avoid problems
specific to tracheal intubation. Since the LMA was introduced into clinical practice in 1988
, various types of LMAs have been developed, the safety and efficacy of which have been
established in both adults and children.The paediatric i-gel is a relatively new and
disposable supraglottic airway device for children, which is made of a soft gel-like
elastomer with a non-inflatable cuff and a channel for gastric catheter placement . It does
not require cuff inflation ,reducing the complications associated with compression trauma and
high cuff pressure . Medical-grade thermoplastic elastomer creates a more intimate interface
for interacting with supraglottic tissue. The usage of i-gel mask is more common in adults
,though a large scale study focusing on children is lacking.
Objectives:
To evaluate the efficacy and performance of the pediatric i-gel mask
Methods:
From November 2018 to March 2019, subjects are selected from patients who undergo elective
surgery at Xi'an Children's Hospital, within the age of 0 to 108 months old, with an American
Society of Anesthesiologists physical status I or II .They were assigned into four groups
according to their weight. Four groups are : 2-5 kg (group 1#), 5.1-12.0 kg (group 1.5#),
10-25kg (group 2#) 25-35kg(group 2.5#). The primary outcome is the clinical performance of
the airways: the rate of insertion at first attempt,the ease of insertion,the insertion
time,the oropharyngeal leak pressure(OLP),the fibreoptic view and the ease of gastric tube
insertion. The secondary outcome is the frequency of other perioperative complications as
listed in the detail information section.
methods This is a prospective, randomized, parallel-group, single sample study ,which was
approved by the Ethics Committee of Children's Hospital affiliated to Xi'an Jiaotong
University.The experiment is expected to be completed between December 2018 and March 2019 in
Xi'an children's Hospital, signed consent will be obtained from the parents or the guardian
of the child participating in the study.The inclusion criteria are: children aged between 0
to 108 months, Weighed between 2 to 35 kg,with an American Standards Association (ASA
)physical status Ι or Ⅱ, who are scheduled for elective surgery shorter than four hours under
general anesthesia . In addition,the operation of supraglottic airway devices needs to be
seamless during perioperative period. Children with below condition will be excluded form the
experiment:a suspected difficult airway, a history of upper respiratory tract infection two
weeks before operation ,being at risk of aspiration (such as non-fasting status ,
gastroesophageal reflux disease and hiatus hernia),lung diseases, limited head-neck
movements, and those refusing to participate.The children with symptoms bradycardia and
conduction block shown on EEG are also excluded from this experiment.The children were
assigned into four groups based on their weights : size 1 for 2-5kg ,size 1.5 for 5-12 kg,
size 2 for 10-25 kg, size 2.5 for 25-35 kg . The required device is prepared according to the
child's weight and using the the manufacturer's guidelines . The children's group allocation
were operated by a researcher who do not participate in post anesthesia care unit or outcome
assessment. All children involved in the experiment, the children's parents, and the data
analyzer are blind to the device used. In preparation for surgery,children are fasted 8h from
solid food with fat content, 6h from semi-solid food and liquid food ,4h for breast milk and
2 h for clear water .Premedication is provided about 20 minutes before entering the operating
room, by which children receive intranasal dexmedetomidine 1.5ug/kg, so that children can
enter the operating room quietly. On arrival in the operating room, children were monitored
using pulse oximetry, electrocardiography, non-invasive blood pressure, and capnography.
General anaesthesia was induced with 100% oxygen 2-4 Liter(L)/min. Injection atropine
0.01mg/kg、fentanyl 2 μg/kg 、 propofol 2mg/kg 、vecuronium bromide 0.1 mg/kg intravenously (IV)
in turn.After loss of consciousness, children are promptly positioned supine with an adequate
sized roll underneath the neck to establish optimal position.Achieving appropriate anesthesia
depth,children are randomised to have inserted i-gel ,The jaw thrust maneuver are used to
confirm anesthesia depth whether it is suitable for placing the laryngeal mask and
facilitating its placement. We do not administer neuromuscular blocking during intraoperative
period. Two anesthesiologists came to the hospital for working at least one year and
experienced in inserting supraglottic airway devices in at least 200 pediatric patients. The
device was inserted according to the manufacturer's recommendations .Device insertion was
considered successful by observing bilateral chest wall movement,as well as a stable
square-wave capnogram trace ,the lung breath sound with no audible leak .Three failed
insertion attempts are considered failed insertion of the device, and patients were withdrawn
from the study.Tracheal intubation was considered after failure of three times of laryngeal
mask airway placement.
Insertion time was measured from the moment a device was picked up until confirmation of the
first wave on a capnogram，The ease of device placement was assessed using a subjective
grading score of 1-4 (1: no resistance, 2: mild resistance, 3: moderate resistance, 4:
inability to place the device) by the anesthesiologist. We also record the manipulations for
improving device position, such as adjusting the insertion depth, conducting a jaw thrust
maneuver, or flexion/extension of the head.
Oropharyngeal leak pressure and fiberoptic view through the device were assessed.
Oropharyngeal leak pressure was determined by closing the adjustable pressure-limiting valve
to 30 centimeter water column(cmH 2 O) at the fresh gas flow rate of 3 L/min, switching the
mechanical ventilation to manual ventilation, and reading the airway pressure on the monitor
in the anesthesia machine which an audible leak on auscultation over neck was defined as OLP.
The OLP was not allowed to exceed 30 cmH 2 O to avoid barotrauma, If mean airway pressure is
higher than OLP or insufficient ventilation (lesser than 5 ml/kg) occurred during the airway
maintenance, proper manipulations (pushing or pulling of device, extension or flexion of the
head, jaw thrust) were performed. If appropriate manipulation does not solve the problem, the
device should be removed and endotracheal intubation be performed. The anatomical position of
the LMA in relation to the glottis was evaluated by placing a fiberoptic bronchoscope through
the device .The fiberoptic view is classified into four grades by observing the fiberoptic
views (grade 1: vocal cords not visible, grade 2: vocal cords and anterior epiglottis
visible, grade 3: vocal cords and posterior epiglottis visible, grade 4: only vocal cords
visible). The 8-12 French size gastric tubes are used for those groups. A well-lubricated
gastric tube is prepared before inserted into the stomach through gastric port of airway
device. The assessment of correct placement is through detection of injected air by
epigastric auscultation or by aspiration of gastric content .A grading
scale(1:easy,2:difficult,3：failure) is used for assessing the ease of gastric tube
insertion.Easy is defined as placing the tube successfully in the first attempt,difficult is
defined as placing the tube successfully within two attempts, failure is defined as inability
to establish correct placement within three placements.Anesthesia was maintained using 2%~3%
sevoflurane and remifentanil 0.2~0.4ug/kg•min.1 ug/kg fentanyl is added again before the skin
incision and suture. At the end of surgery, the anesthetics are terminated. The patient was
then moved to the postanesthesia care unit (PACU).We recorded heart rate, mean blood
pressure, oxygen saturation, peak inspiratory pressure and complications during the induction
and maintenance of anesthesia. At the conclusion of the surgery, when the tidal volume is >6
ml/kg or end-tidal carbon dioxide(CO2) is less than 50 mmHg,we can stop the mechanical
ventilation and keep the patient's spontaneous respiration. The LMA is removed when evidence
of adequate emergence including spontaneous eye opening, grimacing using forehead and/or
eyebrow, and purposeful movement. In addition,we also observed the complication such as
coughing, bronchospasm, laryngospasm, desaturation (SpO 2 < 90%), regurgitation, aspiration,
sore throat, blood-on LMA, postoperative nausea and vomiting (PONV), breath-holding and teeth
or lip injury during anesthesia maintenance and emergence . A blinded investigator assessed
all patients in the PACU and conducted a ward visit or telephone interview 24 h after the end
of surgery. In our study, the primary outcome is oropharyngeal leak pressure，the secondary
outcome are the rate of successful insertion at first attempt, fiberoptic view，insertion
time，ease of insertion，ease of gastric tube insertion。 We recorded complications including
coughing, breath-holding, desaturation, laryngospasm or bronchospasm，blood-on LMA, sore
throat, postoperative nausea and vomiting (PONV), regurgitation, aspiration, teeth or lip
injury.
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