Water precautions for prevention of infection in children with ventilation tubes (grommets)

For the current issue of the Journal, we asked Drs. Adrian James and Gordon Tsang to comment on and put into context the recent Cochrane Review on Water Precautions for Prevention of Infection in Children with Ventilation Tubes (grommets).

BACKGROUND

Following middle ear ventilation tube (tympanostomy tube or grommet) insertion, most surgeons advise that a child’s ears should be kept dry during the immediate postoperative period. Following the initial period, some surgeons will permit swimming or bathing, whereas other surgeons will recommend ongoing water precautions. A large number of studies have been conducted to explore the association between water exposure and ear infections in children with ventilation tubes, however a range of differing conclusions exist regarding the need for water precautions and there is wide variation in clinical practice.

OBJECTIVES

To assess the effectiveness of water precautions for the prevention of ear infections in children with ventilation tubes (grommets), at any time while the tubes are in place.

Search methods

The Cochrane ENT Trials Search Co-ordinator searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2015, Issue 8); PubMed; EMBASE; CINAHL; Web of Science; Clinicaltrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was September 1, 2015.

Selection criteria

Randomized controlled trials recruiting children (0 to 17 years) with ventilation tubes and assessing the effect of water precautions while the tubes are in place. We considered all forms of water precautions, including behavioural (i.e., avoidance or swimming/bathing restrictions) and mechanical (ear plugs/moulds or hats/bands).

Data collection and analysis

We used the standard methodological procedures expected by Cochrane. Our primary outcome measures were episodes of otorrhoea and adverse effects; secondary outcomes were antimicrobial prescriptions for ear infections, ventilation tube extrusion, surgical intervention to remove ventilation tubes and hearing outcomes.

MAIN RESULTS

Two randomized controlled trials recruiting a total of 413 patients met the criteria for inclusion in our review; one study had a low risk of bias and the other study had a high risk of bias.

Ear plugs versus control

One study recruited 201 children (aged 6 months to 6 years) who underwent myringotomy and ventilation tube insertion. The study compared an intervention group who were instructed to swim and bathe with ear plugs with a control group; the participants were followed up at 1-month intervals for 1 year. This study, with low risk of bias, showed that the use of ear plugs results in a small but statistically significant reduction in the rate of otorrhoea from 1.2 episodes to 0.84 episodes in the year of follow-up (mean difference (MD) −0.36 episodes per year, 95% confidence interval (CI) −0.45 to −0.27). There was no significant difference in ventilation tube extrusion or hearing outcomes between the two study arms. No child required surgical intervention to remove ventilation tubes and no adverse events were reported.

Water avoidance versus control

Another study recruited 212 children (aged 3 months to 12 years) who underwent myringotomy and ventilation tube insertion. The study compared an intervention group who were instructed not to swim or submerge their heads while bathing with a control group; the participants were followed up at 3-month intervals for 1 year. This study, with high risk of bias, did not show any evidence of a reduction or increase in the rate of otorrhoea (1.17 episodes per year in both groups; MD 0 episodes, 95% CI −0.14 to 0.14). No other outcomes were reported for this study and no adverse events were reported.

Quality of evidence

The overall quality (GRADE) of the body of evidence for the effect of ear plugs on the rate of otorrhoea and the effect of water avoidance on the rate of otorrhoea are low and very low, respectively.

AUTHORS’ CONCLUSIONS

The baseline rate of ventilation tube otorrhoea and the morbidity associated with it is usually low and therefore careful prior consideration must be given to the efficacy, costs and burdens of any intervention aimed at reducing this rate.

While there is some evidence to suggest that wearing ear plugs reduces the rate of otorrhoea in children with ventilation tubes, clinicians and parents should understand that the absolute reduction in the number of episodes of otorrhoea appears to be very small and is unlikely to be clinically significant. Based on the data available, an average child would have to wear ear plugs for 2.8 years to prevent one episode of otorrhoea.

Some evidence suggests that advising children to avoid swimming or head immersion during bathing does not affect rates of otorrhoea, although good quality data are lacking in this area. Currently, consensus guidelines therefore recommend against the routine use of water precautions on the basis that the limited clinical benefit is outweighed by the associated cost, inconvenience and anxiety.

Future high-quality studies could be undertaken but may not be thought necessary. It is uncertain whether further trials in this area would change the findings of this review or have an impact on practice. Any future high-quality research should focus on determining whether particular groups of children benefit more from water precautions than others, as well as on developing clinical guidelines and their implementation.

The full text of the Cochrane Review is available in The Cochrane Library: Moualed D, Masterson L, Kumar S, Donnelly N. Water precautions for prevention of infection in children with ventilation tubes (grommets). Cochrane Database of Systematic Reviews 2016, Issue 1. Art. No.: CD010375. DOI: 10.1002/14651858.CD010375.pub2.

EXPERT COMMENTARY

It has long been argued that water precautions are unnecessary after myringotomy and ventilation tube (VT) insertion (1) yet many practitioners continue to recommend water avoidance (2). One might imagine that there is little to be lost by advising water avoidance after VT and, consistent with this expectation, no serious adverse effects were reported in this review. However a limitation of randomized controlled trials, and even systematic reviews, is that they are rarely powered to capture rare outcomes. At an anecdotal level, I have long been influenced by a sad case described many years ago of a child who drowned after falling into a canal having been advised not to learn to swim because of tympanostomy tubes. But how much should an anecdote like this influence practice? A counter consideration is that chronically infected ears pose a life-threatening risk from intracranial infection, so taking measures to prevent infection might seem worthwhile. But extraordinarily rare consequences of VT such as these arguably need not influence our recommendations for care. The more everyday question is what causes greater social inconvenience to the child and caregivers: restrictions imposed by water precautions or the chance of an unpleasantly discharging ear.

Using the highest standards of evidence retrieval and analysis, this Cochrane review provides a useful answer to our question. Although the two studies included are rated as having a low quality of evidence using the GRADE system, this is not surprising as some degree of bias is inherent to the question: the child and caregivers are necessarily aware of their allocation to intervention or control so a fully blinded study is not possible. It is perhaps not realistic to expect evidence of a higher quality to address this topic, and as the reviewers suggest, further randomized studies are probably not justifiable.

In our department, we accept and use the guidance which can be concluded from this review, i.e., that water precautions are generally not worthwhile after tube insertion, even though the population of children we treat is skewed towards those with complex systemic disorders or craniofacial anomalies that might be considered to have greater risk of complications. One would imagine that water precautions may be more worthwhile in a child with recurrent tube otorrhoea, as often occurs with primary ciliary dyskinesia, especially if patients notice it after water entry but we have no data to suggest that this is really the case. Our advice is usually qualified to some degree, pointing out the greater risks of infection from unsanitized water or swimming underwater. But it is time consuming to educate parents fully on the relevant facts: soapy water with a lower surface tension penetrates the lumen of a tube more easily (3), as does water depth of >60 cm (4); swimming pool water has a lower bacterial concentration than sea, river or lake water; hot tubes contain pseudomonas if not adequately maintained—which can cause otorrhoea from otitis externa even without VT; absence of any water precautions may lead to only one infection every 2.8 years. In practice, it is much quicker and simpler for a busy physician to recommend complete water precautions after tube insertion for every patient. But this is probably not fair on the child or caregivers. Full instructions can be provided on an information sheet and the cost of protective equipment avoided. When it does occur, tube otorrhoea can usually be controlled readily with antibiotic ear drops (5). Furthermore, encouragement to learn to swim provides an important public health message (6). Is it not reasonable to allow the child with VT to learn to swim unimpeded when the risk of infection is so low, and would that not be easier without hearing impairment from ear plugs?