Comparison between intranasal dexmedetomidine and intranasal ketamine as premedication for procedural sedation in children undergoing MRI; a double blind, randomized, placebo controlled trial.

Introduction and Background:xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /

Sedation is frequently required for children, 1-10 years of age, undergoing magnetic resonance imaging (MRI) to allay anxiety and ensure complete immobility.[1] Different agents have been tried as premedication to render the anaesthesiologist, a calm, comparatively cooperative child for IV cannulation and further procedure.[2] Intranasal route, for premedication, is atraumatic, painless and highly vascular, for rapid absorption and action of drugs. We study and compare the effectiveness of intranasal dexmedetomidine and intranasal ketamine in children undergoing MRI under sedation.

Magnitude:

Children presenting to the MRI suite are frequently anxious and fearful. They do not understand the need of undergoing the diagnostic procedure, and are afraid of lying down, immobile, in a dimly-lit, noisy tunnel. These children require intravenous (IV) cannulation for administrating sedatives, and also to inject contrast agents. Securing a peripheral venous access is difficult in this setting. The children are frequently fearful, anxious and combative. Painful IV cannulation, with the use of restraints, may have long-term psychological consequences in the children, making them afraid of subsequent contacts with health care professionals.[3, 4] Children with psychological, developmental, or behavioural disorders, who most often undergo diagnostic MRI scans, may be combative or aggressive from the outset and require deeper levels of sedation or restraint. Commonly, the procedure has to be carried out in the MRI waiting hall or reception area, in the presence of the child’s parents and other patients. This further adds to the stress of the child and the anesthesiologist.

Rationale of the study:Intranasal administration is relatively easy and convenient, it also reduces first pass metabolism and has been used successfully for dexmedetomidine, ketamine, fentanyl, and midazolam premedication.[5] Previous studies have used dexmedetomidine intranasally in a dose ranging from 1µg/kg to 5µg/kg.[6, 7] However, no study has compared intranasal dexmedetomidine with the intranasal administration of any other drug.

We aim to study and compare the effects of intranasal dexmedetomidine and intranasal ketamine with intranasal placebo (saline) and the assess the satisfaction of the anaesthesiologist, the radiologist and the child’s parents, attained with the use of intranasal drugs.

Material and Methods:

Design of Study: Randomized, Double Blind, Placebo controlled study.

Place of Study: MRI suite, SGPGIMS, Lucknow.

Inclusion Criterion: Age 1-10 years

Undergoing elective MRI under Monitored Anaesthesia Care

Exclusion Criterion: Consent not given

Patients with heart and lung disease

Patients with expected difficult airway

Emergency procedure.

Patients requiring airway intervention or general anaesthesia.

Patients with history of allergy to the drugs to be used.

Preprocedure Requirements: Valid informed consent.

 Procedural Details

1.      Explanation and Consent of the patient for inclusion into the study.

2.      Patients will be randomized by computer generated table and divided into three groups of 45 patients each.

3.      Previous studies have shown that the onset time of adequate sedation after intranasal DXM is 45 minutes with peak effect at 60-90 minutes. The onset of action for intranasal ketamine is within 5-10 minuteswith an duration of action of around 60 minutes.[8-10] For the purpose of blinding, we need to administer the drugs twice to each child as described below.

4.      An independent investigator, not involved with observation or providing anesthesia to the child, will prepare two tuberculin syringes, containing the study drug and diluted to 1ml, for each child and labelled them S1 and S2. The contents of the syringes were as follows:

Group D: S1 will contain DXM (1µg/kg prepared from parenteral preparation of DXM 100 µg/ml) and S2 will be saline.

Group K: S1 will be saline while S2 will contain ketamine (5mg/kg prepared from ketamine 50mg/ml).

Group S: Both S1 and S2 will be plain saline.

5.      The blinded anaesthesiologist, conducting the case, will administer the drugs intranasally into both the nostrils of the child, after explaining the procedure to the child and his parents.S1 will be given 1 hour and S2 will be given 30 minutes before the procedure.

6.      IV access will be obtained 30 minutes after S2. The anaesthesiologist will score the ease of IV cannulation at three stages (when the child’s hands are held, when he is approached with the needle and when skin puncture is done) according to the score used by Beebe et al.[11]

7.      The child will be administered IV midazolam (0.03mg/kg) and glycopyrollate (40µg/kg) after IV access is secured.

8.      The child will be transferred to the MRI table and sedated with 1mg/kg of propofol. After the child is immobile, the procedure will be started.

9.      Monitoring will include SPO2, ETCO2, NIBP. Oxygen supplementation will be by nasal prongs at 2-4litres/minute.

10.  At the end of the procedure, the time to awakening and fitness to discharge will be noted. The child will be observed for 3 hours post procedure and discharged after appropriate advice.

11.   Measurements:

a.       Child’s anxiety at presentation to the MRI suite and his acceptance of intranasal drugs (Annexure 1 and 2).

b.      Hemodynamic parameters at the time of premedication, start of the procedure, every 5 minutes during the procedure and every 15 minutes for 3 hours after the completion of the procedure.

c.       Anaesthesiologist assessment of the ease of cannulation (Annexure 3).

d.      Total Dose of Propofol required for the procedure.

e.       Time till awakening and fitness to discharge (Annexure 4).

f.       The anaesthesiologist, radiologist and parent satisfaction on a scale of 1-5.

g.      Complications during and after the procedure; Hypotension (decrease by 20% from baseline or systolic blood pressure <90 mmHg), bradycardia (decrease in heart rate by 20% from baseline or heart rate <50 beats/min), as well as oxygen desaturation (SpO2 <90%) and upper airway obstruction.

12.  Rescue

a.       Inadequate sedation/ movement will be treated with 0.5 mg/kg boluses of Propofol to maintain stable sedation level.

b.      Hypotension will be treated with Inj Mephentermine in titrated boluses.

c.       In case of desaturation, the child will be taken out of the MRI console and the airway managed appropriately by the anaesthesiologist performing the case.

d.      Bradycardia will be treated with Inj Atropine.

13.  Analysis of data collected by an independent investigator blinded as to the premedication provided.

14.  Appropriate statistical tests will be applied to study the effects of the different interventions.

 References

1.      Koroglu A, Teksan H, Sagir O, Yucel A, Toprak HI, Ersoy OM. A Comparison of the Sedative, Hemodynamic, and Respiratory Effects of Dexmedetomidine and Propofol inChildren Undergoing Magnetic Resonance Imaging. Anesth Analg 2006;103:63–7.

2.      Machata AM, Willschke H, Kabon B, Kettner SC, Marhofer P. Propofol-based sedation regimen for infants and children undergoing ambulatory magnetic resonance imaging. [Br J Anaesth.](http://www.ncbi.nlm.nih.gov/pubmed?term=(Propofol-based%20sedation%20regimen%20for%20infants%20and%20children%20undergoing%20ambulatory%20magnetic%20resonance%20imaging%20A.-M.%20Machata*%2C%20H.%20Willschke%2C%20B.%20Kabon%2C%20S.%20C.%20Kettner%20and%20P.%20Marhofer%20British%20Journal%20of%20Anaesthesia%20101%20(2)%3A%20239%E2%80%9343%20(2008).%20 "British journal of anaesthesia.") 2008 Aug;101(2):239-43.

3.      Dahlquist LM, Gil KM, Armstrong FD, DeLawyer DD, Greene P, Wuori D. Preparing children for medical examinations: the importance of previous medical experience. Health Psychol. 1986;5(3):249-59.

4.      Kleiber C, Sorenson M, Whiteside K, Gronstal BA, Tannous R. Topical anesthetics for intravenous insertion in children: a randomized equivalency study. Pediatrics. 2002 Oct;110(4):758-61.

5.      Warrington SE, Kuhn RJ. Use of intranasal medications in pediatric patients. Orthopedics. 2011 Jun;34(6):456.

6.      Yuen VM, Hui TW, Irwin MG, Yuen MK. A comparison of intranasal dexmedetomidine and oral midazolam for premedication in pediatric anesthesia: a double-blinded randomized controlled trial. Anesth Analg. "Anesthesia and analgesia.") 2008 Jun;106(6):1715-21.

7.      Ghali AM, Mahfouz AK, Al-Bahrani M. Preanesthetic medication in children: A comparison of intranasal dexmedetomidine versus oral midazolam. Saudi J Anaesth. 2011 Oct;5(4):387-91.

8.      Yuen VM, Hui TW, Irwin MG, Yao TJ, Wong GL, Yuen MK. Optimal timing for the administration of intranasal dexmedetomidine for premedication in children. Anaesthesia. 2010 Sep;65(9):922-9.

9.      Iirola T, Vilo S, Manner T, Aantaa R, Lahtinen M, Scheinin M, Olkkola KT. Bioavailability of dexmedetomidine after intranasal administration. Eur J Clin Pharmacol. 2011 Aug;67(8):825-31.

10.      Malinovsky JM, Servin F, Cozian A, Lepage JY, Pinaud M. Ketamine and norketamine plasma concentrations after i.v., nasal and rectal administration in children. Br J Anaesth. 1996 Aug;77(2):203-7.

11.      Beebe DS, Belani KG, Chang PN, Hesse PS, Schuh JS, Liao JC, Palahniuk RJ. Effectiveness of preoperative sedation with rectal midazolam, ketamine, or their combination in young children. Anesth Analg. 1992 Dec;75(6):880-4.

Annexure 1

Presedation Behaviour

xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /1= calm,cooperative

2=anxious,reassurable

3=anxious and not reassurable

4=crying or resisting

  Annexure 2

Acceptance of Intranasal drugs

1= no defense action

2= defense action/weeping

3= refusing vehemently

    Annexure 3

Venipuncture score

When hand is held

Fights with success -      1

Fights without success -2

Minor resistance         - 3

No reaction                  - 4

When approached with needle

Fights with success -      1

Fights without success -2

Minor resistance         - 3

No reaction                  - 4

When skin puncture is done

Fights with success -      1

Fights without success -2

Minor resistance         - 3

No reaction                  - 4

  Annexure 4

Recommended Discharge Criteria

1. Cardiovascular function and airway patency are satisfactory and stable.
2. The patient is easily arousable, and protective reflexes are intact.
3. The patient can talk (if age appropriate).
4. The patient can sit up unaided (if age appropriate).
5. For a very young or handicapped child incapable of the usually expected responses, the presedation level of responsiveness or a level as close as possible to the normal level for that child should be achieved.
6. The state of hydration is adequate.