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A 2-year-old girl presents with 3 days of vomiting and diarrhoea. On examination, she is clinically dehydrated, but haemodynamically stable. Unfortunately, she fails an oral fluid challenge in the department, so she is admitted and rehydrated enterally via a nasogastric tube (NGT). The new medical student attached to the department, upset by watching a screaming child being pinned down, asks you if anything could have been done to make the procedure less distressing for the patient—she recently listened to an American podcast that recommended nebulised local anaesthetic. You realise you have become somewhat desensitised to procedural distress, feel a little guilty and wonder what evidence exists for using topical anaesthetic agents to reduce the distress associated with NGT insertion (NGTI) in children.
Structured clinical question
In a child requiring NGTI (population), does topical local anaesthesia (intervention), compared with placebo (control), reduce the pain and distress associated with insertion (outcome)?
MEDLINE, PubMed, EMBASE, CINAHL, EMCARE, AMED, HMIC and PsychINFO were searched with the following string:
(((nebulis*).ti,ab OR (nebuliz*).ti OR (topical*).ti,ab OR (aerosol*).ti,ab OR (spray*).ti,ab OR (gel*).ti,ab OR (atomi*).ti,ab OR (intranas*).ti,ab OR (jelly).ti,ab OR (applied).ti OR (applic*).ti) AND ((anesth*).ti,ab OR (anaesth*).ti,ab OR (analges*).ti OR (lidocain*).ti,ab OR (lignocain*).ti,ab OR (benzocain*).ti,ab OR (ketamin*).ti,ab OR exp “ANESTHESIA, LOCAL”/ OR exp “ANESTHETICS, LOCAL”/ OR exp “ANALGESIA”/ OR exp “PAIN”/)) AND (exp “INTUBATION, GASTROINTESTINAL”/ OR (nasogastri*).ti,ab OR (“nasogastric tube”).ti OR (NG tube).ti,ab OR (NG).ti). Only English-language articles were examined.
The last search was performed on 28 October 2019. This search retrieved 361 articles, of which two were included in this systematic review (figure 1). These two studies included a total of 136 children aged between 6 months and 5 years.
NGTI has been rated as one of the most distressing procedures performed in the paediatric emergency setting.1 One study2 showed that, although 98% of surveyed emergency doctors consider NGTI to be painful and uncomfortable, only 44% routinely use any anaesthetic agents for amelioration of discomfort. There is reasonably convincing evidence to support routine use of topical local anaesthetic (TLA) for NGTI in adults—one pooled analysis3 of 212 patients from 5 adult studies4–8 suggested that nebulised or atomised lidocaine may produce nearly 60% reduction in procedure-associated pain. A Hong Kong–based study9 of 206 adult patients described that lidocaine spray applied to the nares and pharynx may reduce patient-described pain scores by over 75%, cut the number of failed insertions from 85% to 10%, and halve the number of attempts needed to successfully pass the tube—although an identifiable smell and taste of the lidocaine may have unmasked the intervention group.
However, the evidence for use of TLA during NGTI in children is extremely limited—in this systematic search, only two randomised controlled trials (RCTs) could be identified, both from Australia (table 1). One study10 investigated the use of pre-procedural nebulised lidocaine, whereas the other11 used lidocaine nasal spray. Both studies focused on younger children (up to 5 years old), necessitating the use of observer-derived FLACC (Face, Legs, Activity, Cry, Consolability—table 2) scores as the primary outcome. Although the FLACC score has been validated12 as a tool to measure pain and distress in pre-verbal children, there is little quantitative evidence of how a change in FLACC correlates with a clinically significant difference in pain, and it does not distinguish between pain and psychological distress related to other factors such as holding and unfamiliar surroundings.
Neither of these studies showed a convincing role for the routine use of TLA prior to NGTI in young children. FLACC scores in both studies were extremely high during NGTI—with a median of 9 or above and narrow IQRs—in both study and placebo groups.
The study using nebulisation10 was terminated early due to staff concerns about the high level of distress and treatment delay associated with nebulisation itself. Therefore, it was not powered to detect the expected level of change in the primary outcome. It is possible that the trend to a lower post-procedure FLACC score in the treatment group, compared with saline placebo (3.5 vs 5.5, p=0.10), may have reached significance had the study continued. Supporting this possibility, there was a statistically significant reduction in nurses’ assessment of the overall pain of NGTI immediately post-procedure (visual analogue scale—VAS—22 mm vs 47 mm, p=0.05) and in the researcher-observed pain VAS score post-procedure (0 mm vs 23 mm, p=0.01).
These findings hint that LA may be effective in improving post-procedural comfort after NGTI, even if the procedure itself remains distressing. One could reasonably hypothesise, therefore, that TLA could reduce the number of young children who pull out their NGTs after insertion, requiring re-insertion or escalation to intravenous therapy—an outcome worthy of further study. Doses of up to 8 mg/kg nebulised lidocaine have been demonstrated to have a good safety profile in the context of flexible bronchoscopy for children,13 which is double that used in this study.
The remaining study11 is therefore the only sufficiently powered study testing TLA for NGTI, with 100 participants, and the method of application of local anaesthetic was chosen to minimise the distress of the TLA itself. Despite this, no effect was seen on procedural FLACC scores or parent/researcher VAS for pain and distress. Of note, FLACC scores were reasonably elevated immediately prior to NGTI during positioning, reflecting the distress associated with holding or restraint for any procedure, which may be a reason for persistent distress despite any reduction in actual pain experienced.
The lidocaine dosage used in the study may not have been optimal. The broad weight-banded dosing schedule of lidocaine used was designed for simplicity and may therefore not have had maximal anaesthetic efficacy. Some children at the heavier end of the 6–12 kg weight band will have received less than 1 mg/kg of topical lidocaine, and even the lightest baby would have received <2 mg/kg. Furthermore, the dose was divided between the two nostrils. In contrast, the British National Formulary advises use of 3 mg/kg for lidocaine spray in relation to flexible bronchoscopy.14 Previous study protocols6 15 have included pre-selection of the most patent nostril in order to maximise the anaesthetic applied to that single nostril.
It would be reasonable to consider further study of this young population using higher doses of TLA spray, with the entire dose administered to a pre-selected nostril, or consideration of LA spray to both the nose and to the pharynx, as per the protocol of previous adult studies.6 14 If a future study could more effectively target the maximal safe dose of anaesthetic to the nasopharynx, then a sufficiently clinically relevant effect might still be demonstrated for young children. It would also be worthwhile to investigate whether or not TLA can improve post-procedure tolerance and retention of NGTs in any future study.
There are no studies investigating TLA for NGTI for children between 6 and 18 years of age, which likely reflects that the paediatric indications for NGTI are largely most relevant to the younger age group (eg. hydration in bronchiolitis and gastroenteritis). However, the use of a NGT is still fairly common on paediatric wards for older children, for both medical and surgical indications. NGTI is also sometimes required during inpatient management of eating disorders. Adult studies are arguably more transferable to the adolescent and older child populations, as long as the patient has sufficient understanding of the role of local anaesthetic and the nature of its administration, and an ability to co-operate with the procedure. This is because there is little reason to suspect that local anaesthetic applied to mucous membranes would work differently in children and adults, once the correct dosage regime has been found—therefore the differences in clinical efficacy are likely to relate to whether the child finds the application of local anaesthetic, and any associated restraint, distressing because of their developmental and cognitive abilities. The adult studies did not use a weight-based dosing schedule and excluded those weighing less than 45 kg8 and 50 kg,4 so if local anaesthetic was used in this setting in older children, it would be dosed based on formulary recommendations rather than specific evidence.
Clinical Bottom Lines
Current evidence suggests that nebulised or sprayed topical local anaesthetic does not reduce the pain and distress associated with nasogastric tube insertion in children up to 5 years old, although the only adequately powered study used dosing schedules that significantly under-dosed each child (Grade Of Recommendation: Low).
Given the strong evidence for analgesic effect in adults, topical local anaesthetic (nebulised or aerosolised) can be considered in co-operative older children, particularly those weighing over 45 kg (Grade of Recommendation: Moderate).
Many thanks to Liz Callow (Cairns Library, John Radcliffe Hospital, Oxford) for her guidance in the creation of the search terms used in this systematic review.
Contributors DOM designed the systematic search terms, performed the search and subsequent paper selection, wrote the manuscript draft, and designed the figure and tables. IL identified the topic for systematic review, supervised the search strategy and paper selection, and revised the manuscript, figure and tables.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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