Nitroglycerin to Facilitate Radial Arterial Catheter Insertion in Children

Study Overview
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Brief Summary
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Local nitroglycerin (NTG) was successfully used as a vasodilator to facilitate cannulation of the radial artery. NTG was used in adults by topical application as well as subcutaneous infiltration. Subcutaneous infiltration of NTG resulted in significant vasodilatation, improved palpability of the radial artery, reduced the number of punctures and the time needed for cannulation in adults. Topical NTG was reported to increase radial artery diameter in healthy volunteers without reduction in arterial blood pressure. In pediatric population, there no sufficient evidence for the effectiveness of NTG in improving radial artery cannulation. In a case report on two neonates, topical nitroderm ointment successfully reversed tissue ischemia secondary to radial artery cannulation The aim of this work is to evaluate the use of topical NTG (patch) for increasing the diameter of radial artery, improving the cannulation success, and decreasing catheter-related ischemic complications.

Detailed Description
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A written informed consent will be obtained from patient's parents or guardians. Randomization will be obtained using computer-generated sequence. Concealment will be obtained using opaque envelopes. On arrival to the preparing room, patients will be randomized into one of the two groups: - NTG group or, Control group Ultrasound examination: The diameter of radial artery will be measured using a linear, high frequency probe (12 mHz) of Simens machine. Measurement will be obtained in the short axis plane at the point with maximal pulsation. The point will be marked to guide the post-intervention examination. The operator will be an experienced single operator blinded to the study group. Measurements will be obtained in both limbs at baseline (before application of NTG patch application,30 minutes,60minutes after NTG application After induction of anesthesia, radial artery will be punctured by 22-g catheter by an experienced anesthetist

Official Title
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Topical Nitroglycerin to Facilitate Radial Arterial Catheter Insertion in Children: a Randomized Controlled Study

Conditions
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Radial Artery Canulation

Intervention / Treatment
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* Drug: NTG patch
* Other: gauze cover


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: children aged between 2 and 5 years scheduled for cardiac surgery Exclusion Criteria: Systolic blood pressure less than 90 mmHg, previous radial artery puncture abnormal Allen's test hypercoagulable states coagulopathy previous vascular complications

Ages Eligible for Study
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Minimum Age: 2 Years
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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: NTG group<br>In this group, nitroglycerin patch will be applied near the radial artery pulsation covered with a gauze. | Drug: NTG patch<br>* A half-NTG patch (dose calculated at 5-12.5 mcg/kg/hr) will be applied to patients at the site of radial pulsation one hour before induction of anesthesia. The NTG patch will be applied to the right upper in half of the patients and will be applied to the left upper limb in the other half<br>Other: gauze cover<br>* A gauze will be applied near the radial artery pulsation to ensure blinding<br>|
| Placebo Comparator: Control group<br>In this group, no patch as applied to the patient. However, a gauze will be applied to confirm blinding | Other: gauze cover<br>* A gauze will be applied near the radial artery pulsation to ensure blinding<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in The diameter of radial artery | mm | 1 minutes before intervention then 30 and 60-minutes after the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| palpability of radial pulse after NTG patch application | Grade 0: palpability did not change after NTG, grade 1: palpability improved after NTG, grade 2: palpability became bounding after NTG | 1 minutes before intervention then 30 and 60-minutes after the intervention | 
| Number of arterial punctures | number | 30 minutes | 
| successful cannulation confirmed | incidence | 30 minutes | 
| successful first-puncture cannulation | incidence | 30 minutes | 
| postoperative ischemic complications | incidence | 24 hours post intervention | 
| systolic blood pressure | mmHg | 1 minute before the intervention, every 5 minutes for 1 hour |