European Journal of Cardiovascular Medicine

Direct laryngoscopy and tracheal intubation is associated with a rise in the hemodynamic responses as well as intraocular pressure.¹ Pediatric airway is different from adult and the complications associated with laryngoscopy and intubation is higher. The use of supraglottic airway devices to maintain airway have been very effective in reducing the pressor response associated with tracheal intubation.^2,3 I-gel is a second generation supraglottic airway device made of a soft gel-like thermoplastic elastomer with a non-inflatable cuff. I-gel has got a channel for gastric suction catheter placement and its design is compatible with the anatomical structures so that it causes minimal pharyngeal tissue compression.⁴ The ease of insertion, lack of high cuff pressure and gastric suction channel makes I-gel superior to other cuffed supraglottic airway devices in pediatric age group.⁵ Many studies suggest the safe and effective use of I-gel in pediatric patients and it does not differ from laryngeal mask airway in terms of airway leak pressure.^6,7,8 Avoiding a sharp rise in intraocular pressure and hemodynamic response during airway management would be beneficial in pediatric ophthalmology surgical procedures including cataract surgeries, glaucoma surgeries, penetrating eye injuries and other high risk cases. The objectives of our study was to compare the change in intraocular pressure, heart rate and blood pressure associated with endotracheal intubation and I-gel insertion in pediatric patients and to assess any adverse events associated with use of I-gel in paediatric age group. The null hypothesis was that there is no difference in change in intraocular pressure or hemodynamic responses associated with tracheal intubation and I-gel insertion in pediatric age group

The study was a prospective randomized controll trial. It was a comparative study with 60 pediatric patients of age group 2-12 yrs, undergoing strabismus surgery. The study duration was six months. Inclusion criterias were ASA physical status I/ II, Age group 2- 12yrs, Both males and females were included in the study. Exclusion criteria were Patients with difficult airway, Patients with a history of allergy to multiple drugs, Cases of intubation following failure of I-gel insertion, patients with history of raised ICP. Patients were randomized into groups A and B of 30 each by a sealed envelope method. Group A patients airway was managed by I-gel supraglottic device and group B by tracheal intubation. The variables assessed were Intraocular pressure (IOP) of both eyes, Heart rate, Systolic blood pressure (Non-invasive blood pressure), Mean arterial pressure (Non-invasive blood pressure), Breath holding on extubation. The instrument used fo the study was Perkins applanation tonometer for measuring IOP.

Procedure:

After getting institutional ethical committee approval 60 patients of age group 2-12 years undergoing elective strabismus surgery were randomly divided into two groups. A thorough pre-anesthetic evaluation and blood investigations including hemoglobin, total count and screening for HIV, HBsAg and HCV was conducted. Six hours fasting for light meal or formula feeds, 4 hours for breast milk and 2 hours for clear fluids was mandatory. All patients were premedicated with oral midazolam 0.5mg/kg and prilocaine 2.5% w/w + lignocaine 2.5% w/w gel over dorsal aspect of both hands one hour prior to shifting to operating room. In the operating room patients were monitored with multipara monitor and baseline heart rate (HR), systolic blood pressure(SBP), mean arterial pressure(MAP) continuous ECG and SpO2 were recorded. All patients received a standardized general anesthetic. An intravenous (IV) access was established. Anaesthesia was induced with injection propofol 2.5 mg/kg slow IV. Inj. Fentanyl 1 mcg/kg is given intravenously followed by inj. Atracurium 0.5mg /kg. IOP is measured by ophthalmology resident who was blinded to the study prior to intubation or I-gel insertion. In group A airway was managed by I-gel Airway device and in group B by endotracheal intubation. IOP was again measured immediately following airway securement and at 5 minutes. Residual neuromuscular blockade was reversed by neostigmine 50µg/kg and glycopyrrolate 10µg/kg, once the patients started spontaneous breaths. When the spontaneous respirations were adequate suction of the throat was done and tracheal extubation/ I-gel removal was performed. The occurrence of coughing or gagging, breath holding, laryngospasm and bronchospasm during and after extubation was noted.

The demographics of the two groups were age comparable. The mean age of group A was 5.77±2.69 and group B was 6.30±2.67 (p = 0.443) and mean weight was 21.47±9.87 in group A and 22.53±8.68 in group B (p = 0.658). Two groups were also gender matched with 17(56.7%) males & 13(43.3%) females in group A and 12(40%) males & 18(60%) females in group B. The baseline haemodynamic parameters were comparable between the groups.  Baseline heart rate (HR) in group A was 83.30±12.96 and in group B was 83.83±8.74 (p = 0.852). HR increased in both groups immediately following airway intervention and was found to be higher at 5 minutes after intervention. The HR immediately after airway intervention was 94.50±12.66 in group A and 101.33±14.07 in group B which was statistically not significant (p=0.053). The HR at 5minutes following intervention in group A was 87.23±14.89 and in group B 89.23±13.40 (p = 0.587). The baseline mean arterial pressure (MAP) was 58.57±6.26 in group A and 58.60±7.27 in group B which was comparable. Immediately after airway intervention there was significant rise in MAP in both groups. The increase in MAP in group B (71.17±7.76) was significantly higher compared to group A (63.27±6.92) with a p value <0.001.

The MAP decreased towards baseline at five minutes in both groups but group B had a higher MAP (61.67±5.59) compared to group A (59.30±7.43) with a p value of 0.169. Baseline intraocular pressure (IOP) in the right eye was 10.37±1.73 in group A and 10.23±2.22 in group B which was comparable. Immediately after airway intervention there was a rise in IOP measured in right eye in both groups. IOP in right eye increased to 10.87±1.87 from baseline (p = 0.117) in group A and to 13.47±2.66 in group B (p<0.001). The values were statistically significant between the two groups (p<0.001).

At 5 minutes IOP returned towards baseline with a reading of 10.20±1.69 in group A and 11.33±2.20

in group B which was statistically significant between the groups (p =0.029)

Similarly, the baseline IOP was comparable in the left eye also with a reading 10.30±1.56 in group A and 10.30±2.81 in group B (p = 1.000). A rise in IOP was noted in left eye soon after airway intervention in group A (10.88±1.96) as well as group B (13.47±3.64) with a p value of 0.001 which was statistically significant between the groups.

At 5 minutes of intervention the IOP remained higher in group B (11.30±2.07) compared to group A (10.23±1.79) with a p value of 0.037.

Coughing and gagging was noticed during extubation in 1(3.3%) case in group A and 7(23.3%) cases in group B with a p value < 0.05 and breath holding was noticed in 3 cases in group B and no cases in group A (p = 0.237). Aspiration was not reported in any of the cases.

Statistical Methods: Descriptive and inferential statistical analysis has been carried out in the present study. Results on continuous measurements are presented on Mean ± SD (Min-Max) and results on categorical measurements are presented in Number (%). Significance is assessed at 5% level of significance. The following assumptions on data is made 1. dependent variables should be normally distributed 2. samples drawn from the population should be random, cases of the samples should be independent.

Student t test (two tailed, independent) has been used to find the significance of study parameters on continuous scale between two groups (Inter group analysis) on metric parameters. Leven`s test for homogeneity of variance has been performed to assess the homogeneity of variance. Student t test (two tailed, dependent) has been used to find the significance of study parameters on continuous scale with in each group.  Chi-square/ Fisher Exact test has been used to find the significance of study parameters on categorical scale between two or more groups, non-parametric setting for qualitative data analysis. Fisher Exact test used when cell samples are very small.

Statistical software: The Statistical software namely SPSS 22.0, and R environment ver.3.2.2 were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc.

I gel supragottic airway device is increasingly being used in pediatric general anaesthesia as an alternative to endotracheal intubation. We noticed a rise in heart rate (HR) following the airway management in both study groups but was found to be statistically not significant. A significant rise in mean arterial pressure (MAP) was observed in patients with endotracheal intubation. Previous studies have shown better hemodynamic stability in terms of  HR and MAP in adult patients.¹³ Overall haemodynamic stability was found to be better with I gel insertion compared to endotracheal intubation. Intra ocular pressure (IOP) was measured by Perkins tonometer. There was significant increase in the IOP measured in both eyes immediately following tracheal intubation whereas modest change was noticed in study group where I-gel airway device was used. The IOP levels between the two groups were also statistically significant. Our observation is in accordance with findings of Ismail SA et al ¹³ in adult patients who suggested I-gel device provides better stability of IOP. The raised IOP was found to persist even after 5 minutes of intervention in kids who were intubated. The IOP in I-gel group was found to be close to baseline at 5 minutes after insertion. This clearly shows the advantage of using I-gel supraglottic device over tracheal intubation and will be helpful in patients with clinical conditions where a rise in IOP is not desirable during general anaesthesia. Alparslan Sahin et al⁹ found that I-gel airway device insertion with sevoflurane or desflurane inhalation anesthetics seemed not to cause any rise in IOP in pediatric strabismus surgery.

I-gel is a safe and effective airway management device which provides better haemodynamic stability and stable intra ocular pressure in general anaesthesia for pediatric strabismus surgeries

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