Sedation of children undergoing magnetic resonance imaging
Manchester, UK
* E-mail: o.dearlove{at}man.ac.uk
Editor—We were interested to read the correspondence between Allen1 and Sury and colleagues2 on paediatric sedation, having reported a series in 1999. Changes in our sedation regime3 were introduced in 2000. We have since tracked our results for sedation to facilitate MRI scanning in children. In the last five years from 2002 to 2006, we have performed 4165 sedations and 478 general anaesthetics for MRI scan (the general anaesthesia group being a mixture of those who failed sedation and those referred for general anaesthesia directly).
Our sedation technique can be summed up as oral chloral hydrate 100 mg kg–1 to a maximum of 2 g, with or without rectal paraldehyde 0.3 ml kg–1 for children weighing <20 kg, and oral quinalbarbitone (secobarbital) 10 mg kg–1 to a maximum of 200 mg for those weighing >20 kg.4
We have had five critical incidents compared with the nil critical incidents of Sury and colleagues,2 and this may reflect a different population undergoing sedation for MRI in the North West. Most of these were airway-led, as predicted by Cote and colleagues.5 This means that the critical incidents were, if not avoidable, then treatable by standard means. During this time, we had one critical incident in the general anaesthetic group. This was a failure to anaesthetize.
Our series is large, and critical incidents are to be expected. The correspondence1 sums up the current tensions in providing a service for sedation of children. Various points arise from it. The demand for sedation in a hospital is huge, and there is little interest in anaesthetists who like to anaesthetize rather than sedate or supervise. In order to show safety, it is necessary to perform very large numbers of procedures and audit them as we have done. If ‘safe’ means zero critical incidents, then there will be a pressure to under report. ‘Safe’ we think is a situation where random events are treated by trained personnel in a timely fashion and without an adverse outcome.
Sury and colleagues6 refer to the use of melatonin, which did not contribute to sedation. The failure rate was 30% in Wassmer's series7 and we would rate this as so high as to make it impractical. Our failure rate was 11%, 478 of 4165 patients.
Sury suggests that there is a widely held view by anaesthetists that anaesthesia is safer than sedation for MRI in children. MRI in children tends to be a standard non-painful procedure. Many sedations are performed by nurses under supervision, and most anaesthetics are performed by anaesthetists. We do not know how safe sedation services in the UK are, as results are underreported. Clearly, if we do a lot, we should be reporting our results.
We found that there was a group of children for whom it was safer to anaesthetize than sedate—children with mucopolysaccharidosis. Nonetheless, the waiting times for scan become quickly unmanageable if too many well-children are referred directly for general anaesthesia. Secondly, Malik and colleagues4 have reported a series of children who were assessed for stridor under general anaesthesia and then sedated for MRI scanning, who are included in this series.
Guaranteeing a scan after a single visit to hospital is possible, and general anaesthesia will figure greatly in this system. This is the one that Allen1 describes. We find that one session is suitable for around 150 scans yr–1. And so if one needs a thousand scans under sedation, to do it in this fashion would require 10 sessions—or the whole week. It is difficult to scale up a service to 10 times the volume.
A sedation service has to be safe; however, safety is open to interpretation and the service must also be available. Allen's series of 200 children, although admirable, does not show this. The demand for sedation is such that if there is no anaesthetist to provide it or supervise it, the sedation will still go ahead, but provided by someone else without anaesthetic skills. Cote and colleagues5 have reported a long series showing how things can go wrong and how most critical incidents were airway led. Anaesthetists are well placed to treat those incidents that are most likely to occur during sedation, which are airway problems. Safe sedation services provide a challenge for the anaesthetist, a challenge to which we must rise.
References
1 Allen JG. (2006) Sedation of children undergoing magnetic resonance imaging. Br J Anaesth 97:898–9.
2 Sury MRJ, Hatch DJ, Deeley T, et al. (1999) Development of a nurse led sedation service for paediatric magnetic resonance imaging. Lancet 353:1667–71.[CrossRef][Web of Science][Medline]
3 Keengwe IN, Hegde S, Dearlove O, et al. (1999) Structured sedation programme for magnetic resonance imaging examination in children. Anaesthesia 54:1069–72.[CrossRef][Web of Science][Medline]
4 Malik TH, Bruce IA, Kaushik V. (2006) The role of MRI in the assessment of suspected extrinsic tracheobronchial compression due to vascular anomalies. Arch Dis Child 91:52–5.
5 Cote CJ, Notterman DA, Karl HW, et al. (2000) Adverse sedation events in pediatrics. A critical incident analysis of contributing factors. Pediatrics 105:805–15.
6 Sury M and Fairweather K. (2006) Effects of melatonin on children undergoing sedation. Br J Anaesth 97:220–5.
7 Wassmer E, Fogarty M, Page A, et al. (2001) Melatonin as a sedation for diagnostic procedures MRI and EEG. Dev Med Child Neurol 43:136.[Web of Science][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A.-M. Machata, H. Willschke, B. Kabon, S. C. Kettner, and P. Marhofer Propofol-based sedation regimen for infants and children undergoing ambulatory magnetic resonance imaging Br. J. Anaesth., August 1, 2008; 101(2): 239 - 243. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||