Gowning by attendants and visitors in newborn nurseries for prevention of neonatal morbidity and mortality

Webster J, Pritchard MA

Background - Methods - Results - Characteristics of Included Studies - References - Data Tables and Graphs
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Dates

Date edited: 19/05/2006
Date of last substantive update: 31/01/2003
Date of last minor update: 05/04/2006
Date next stage expected 31/05/2006
Protocol first published: Issue 2, 2002
Review first published: Issue 3, 2003

Contact reviewer

Joan Webster
Nursing Director, Research
Teaching and Research
Royal Brisbane and Royal Women's Hospital and Health Service Districts
Level 6, Ned Hanlon Building
Butterfield Street
Herston
QLD AUSTRALIA
4029
Telephone 1: +61 7 3636 8590
Telephone 2: +61 7 3636 3140
Facsimile: +61 7 3636 2123
E-mail: joan_webster@health.qld.gov.au

Contribution of reviewers

Internal sources of support

None

External sources of support

Centre for Clinical Studies - Women's and Children's Health, Mater Hospital, Sth Brisbane, Queensland, AUSTRALIA
Department of Health and Ageing, Commonwealth Government, Canberra ACT, AUSTRALIA

What's new

This review updates the existing review of "Gowning by attendants and visitors in newborn nurseries for prevention of neonatal morbidity and mortality" which was published in The Cochrane Library Issue 2, 2003 (Webster 2003).
No new trials were identified as a result of this updated search. The conclusions of the review are unchanged.

Text of review

Synopsis

Gowning by attendants and visitors in newborn nurseries for prevention of neonatal morbidity and mortality
Newborn nurseries and neonatal intensive care units often require staff and visitors to wear overgowns with the intention of preventing the spread of infection. It has also been thought that putting on an overgown will remind people to wash their hands, which is of proven importance in preventing infection. A review of the medical literature identified eight clinical trials on gowning in these settings, involving 3811 newborns. Infection rates, death rates, or the length of stay of infants were not significantly affected by wearing gowns. Only two of the trials were considered to be of good quality, and there was variation between trials regarding gowning policies. Gowning did not increase the rate of handwashing. There is no evidence to support the use of gowning by staff to prevent the spread of infection. Based on these studies, gowning may not be a cost effective policy.

Abstract

Background

Overgowns are widely used in newborn nurseries and neonatal intensive care units. It is thought that gowns may help to prevent the spread of nosocomial infection and serve as a reminder to staff and visitors to wash their hands before contact with the infant.

Objectives

The objective of this review is to assess the effects of the wearing of an overgown by attendants and visitors on the incidence of infection and death in infants in newborn nurseries.

Search strategy

The standard methods of the Cochrane Collaboration and its Neonatal Review Group were used. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - April 2006) and CINAHL (1982 - April 2006).

Selection criteria

The review includes all published trials using random or quasi-random patient allocation, in which overgowns worn by attendants or visitors were compared with no overgowns worn by attendants or visitors.

Data collection & analysis

The standard methods of the Cochrane Collaboration and its Neonatal Review Group were used. Data extraction and study quality were independently assessed by the two review authors. Missing information was sought from three authors but only one responded. Results are expressed as relative risk or mean difference with 95% confidence intervals .

Main results

Eight trials were included, reporting outcomes for 3,811 infants. Trial quality varied, with only two assessed as being of good quality. Not wearing overgowns was associated with a trend to reduction in the death rate (typical RR 0.84; 95% CI 0.70, 1.02) compared to wearing overgowns, but these results did not reach statistical significance. There was no statistically significant effect of gowning policy on incidence of systemic nosocomial infection, (typical RR 1.24; CI 0.90,1.71). The overall analysis showed no significant effects of gowning policy on the incidence of colonisation, length of hospital stay or handwashing frequency. No trials of visitor gowning were found.

Reviewers' conclusions

There is no evidence from this systematic review and meta-analysis to demonstrate that overgowns are effective in limiting death, infection or bacterial colonisation in infants admitted to newborn nurseries.

Background

Newborn infants, particularly those admitted to neonatal intensive care units, are at risk for a variety of bacterial, viral and fungal infections (Gaynes 1996). Neonatal infection carries a high risk of morbidity and mortality, especially among very low birth weight infants (Barton 1999). Reasons for higher rates of infection amongst newborns includes their lowered ability to resist disease agents (Levy 1999), exposure to endemic nursery pathogens (Foca 2000; Webster 1994), prolonged use of central venous catheters (Chathas 1990) and exposure to intrauterine infections (Seaward 1998).
Organisms introduced into the nursery may be transmitted to other infants by a variety of routes making cross infection a particular problem (Baltimore 1998). A colonised or infected infant has the potential to impact on the colonisation or infection rates in particular time periods. Handwashing is recognised as the single most effective method of reducing the transmission of microorganisms between patients (Larson 1999) and is an integral part of hospital infection control programs. Other practices, such as various barrier methods, are also used to control cross infection in hospitals. Gowning is one barrier method of infection control frequently used to restrict the transmission of infection (Cloney 1986). It is common practice for attendants and visitors to wear overgowns in some neonatal intensive care nurseries. For attendants, this is to prevent patient-to-patient transmission of microorganisms and infection; for visitors, it is to protect newborns from organisms which they may carry. Although wearing overgowns is believed to increase compliance with hand washing, one non-controlled study has not demonstrated this effect (Donowitz 1987). In recent times, cost considerations have led some institutions to abandon the use of overgowns in newborn nurseries (Thigpen 1991).
Although many centres use overgowns for attendants and visitors as a means of infection control in newborn nurseries and neonatal intensive care units, the benefits and risks of gowning remain unclear.

Objectives

Primary:
To determine the effects of wearing overgowns, compared to no gowns, by attendants and visitors to newborn infants admitted to a Neonatal Intensive Care Unit or a Newborn Nursery on hospital acquired infection and death.

Secondary:
To determine the effects of wearing overgowns for subgroups of newborn infants by gestational age, by nursery type and by visitors and attendants.

Criteria for considering studies for this review

Types of studies

Randomised or quasi-randomised controlled trials in which the unit of allocation is either the individual or a cluster (such as randomisation by physician or hospital or time period).

Types of participants

Attendants of infants admitted to a neonatal intensive care or newborn nursery.
Visitors to infants admitted to a neonatal intensive care or newborn nursery.
The unit of randomization will either be the individual infant or the entire unit/service.

Types of interventions

Use of overgowns compared with no gowns by attendants and visitors in the care of newborn infants.

Types of outcome measures

Primary: • Death (before discharge from nursery) • Systemic nosocomial infection (any systemic infection identified > 48 hours after admission to the nursery) • Localised nosocomial infection (any localised infection identified > 48 hours after admission to the nursery) (Garner 1996)
Secondary:
• Nosocomial colonisation (bacterial colonisation of any site cultured, identified > 48 hours after admissions to the nursery) • Cost (directly related to laundering and replacement of gowns and time taken to 'gown') • Handwashing (frequency) • Length of stay (days)
In addition for preterm infants: • Duration of mechanical ventilation (days) • Duration of neonatal intensive care nursery stay (days) • Antibiotic use
Subgroup analyses were planned on the basis of nursery type (well baby nursery and intensive care nursery), gestational age at birth (37 or more completed weeks, < 37 to 30 completed weeks and < 30 weeks) and by visitors and attendants.

Search strategy for identification of studies

The standard search strategy of the Cochrane Neonatal Group was used. See: Cochrane Neonatal Group search strategy. The review authors conducted searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - April 2006), CINAHL (1982- April 2006), which were published in the English language, using MeSH terms infant- preterm, infant-newborn, cross infection-prevention, cross infection-control, protective clothing and text words neonat*, overgown, cover gown, infection*, intensive care unit, nurser* hospital, gown* and colonis* postpartum, handwash*. The Oxford Data Base of Perinatal Trials was searched for unpublished trials.

Methods of the review

The standard methods of the Cochrane Collaboration and its Neonatal Review Group were used. The methodological quality of each trial was independently reviewed by each review author taking account of blinding at randomisation, intervention and outcome measurement and completeness of follow-up. Additional information was sought from three trial authors.
Review authors independently assessed whether studies met the inclusion criteria, and extracted data. Results were compared and discrepancies resolved by consensus or referral to a third party.
Data from each trial were analysed using the Cochrane Neonatal Group's standard methods which include the use of relative risk for categorical data and mean difference for data measured on a continuous scale. 95% confidence intervals are presented for all measures of treatment effect. Trials which allocated clusters of patients to each intervention were not analysed using the number of clusters as the unit of analysis, as intended in the protocol, but analysed as if the allocation was by individual. This was necessary because none of the authors of these trials used the cluster as the unit of analysis. Analysing cluster trials in this way has the potential to over-estimate the effect of treatment (Mollison 2000). Consequently, for each outcome there is a meta-analysis of all trials and also of two sub-groups where appropriate, one which includes the trials which randomised the individual participant and one which includes the cluster allocated trials. For meta-analysis, we used a fixed effect model.
We assessed heterogeneity between results using the I2 statistic (Higgins 2003). This examined the percentage of total variation across studies due to heterogeneity rather than chance. We used a random effects model where the values of I2 were over 50%, indicating a high level of heterogeneity. For all other meta analyses, we used a fixed effect model.

Description of studies

Twelve studies were identified, of which four were excluded for the reasons given in the Table, Characteristics of Excluded Studies. Eight studies were considered eligible for inclusion in the review. See Table, Characteristics of Included Studies.
Three of the studies randomised by individual infants. Each of these was conducted in a well baby, full-term nursery (Forfar 1958; Birenbaum 1990; Rush 1990). In two of these studies, rooming in was practiced and infants spent only short periods of time in the nursery (Birenbaum 1990; Rush 1990) . Methods used in the three studies were similar with staff and visitors in the control arm using gowns and those in the experimental arm not wearing gowns. In both groups, infection control precautions, such as handwashing before entering the nursery and before and after handling infants, were observed.
Five studies used cluster allocation by alternating blocks of time for the gown and no-gown periods, in either neonatal intensive care or special care nurseries (Silverman 1967; Evans 1971; Agbayani 1981; Pelke 1994; Tan 1995). In the gowning time periods, gowns were worn by all staff and visitors on entering the nursery and for all infant contacts. In the no-gown time periods, there were between study variations in how 'gowning' was defined. In the earlier studies (Silverman 1967; Evans 1971; Agbayani 1981), gowns were not worn when entering the nursery but they were worn if the incubator hood was opened or when an infant was being held. In the two later studies (Pelke 1994; Tan 1995), gowns were not used at all during the no-gown periods. In the Tan 1995 trial, gowns were defined as a plastic apron.
Alternate time periods used in each study were two or three-month blocks, and the length of studies varied between eight to 25 months. One study attempted to eliminate exposure effects from one time period to another by excluding infants who were admitted in the last 10 days of each two month interval (Agbayani 1981). Adjustment for seasonal biases was made in a further study where the gowning period was extended for one month at the end of the first 12 months to ensure a different distribution of gowning periods in the second year (Silverman 1967). One study provided evidence of community follow-up to establish if any infections had occurred after hospital discharge (Birenbaum 1990).
Each infant was allocated to the gowning and no-gowning groups according to the gowning policy in place during the month the infant was admitted, and outcomes for that infant were attributed to the gowning policy as allocated on admission.
Evans 1971 and Agbayani 1981 reported nasal and umbilical colonisation rates by day of life for the gown and no-gown groups (Evans 1971 on days 2, 4, 6, 8, 10, 14 and 21 and Agbayani 1981 on days 1, 2, 4, 7, 10, 21 and 28). We chose day four results for the meta-analysis to ensure that colonisation was nosocomial (i.e. acquired more than 48 hours after admission) and to maximise the number included in the sample (i.e. it was not until day 10 when similar days were again used for reporting and by this time, many of the infants had been discharged). Groin swabs were also analysed using day four results (Agbayani 1981).
Effect by visitors and attendants
None of the studies reported on independent effects of wearing gowns by either visitors or attendants. All of the included studies focused on comparisons when both the visitors and attendants wore or did not wear gowns.

Methodological quality of included studies

See: Table, Characteristics of Included Studies
Concealment of allocation
There was adequate concealment of allocation in two of the trials (Birenbaum 1990; Rush 1990), each randomising the individual patient. One used shuffled sealed envelopes (Birenbaum 1990) and the second used consecutively numbered sealed envelopes that contained a folded card with the group allocation (Rush 1990). No information was provided for the allocation technique used by Forfar 1958, but it is stated that infants were randomly assigned to one of two full term nurseries. None of the trials using cluster allocation used randomly allocated periods for the intervention; all use pre-determined two or three month blocks.
Blinding
Blinding of the intervention was not possible. Blinding of outcome assessment was reported in only one study (Rush 1990).
Completeness of follow-up
In the Birenbaum 1990 study, there was no indication of how many infants were randomised on admission to either the gown or no-gown groups. Infants were excluded if they did not have nose and umbilical cultures taken within six hours of delivery or if they did not have cultures taken before discharge. This makes the possibility of attrition bias likely. Rush 1990 enrolled 234 infants in the no-gown group and 239 infants in the gown group. Length of stay was the only outcome calculated using these numbers. Infection and colonisation data were reported on 222 infants and 230 infants respectively. In the Forfar 1958 trial, follow-up data are complete for infection but not for colonisation. There were also incomplete colonisation data in the Evans 1971; Agbayani 1981; and the Pelke 1994 trials.

Results

See: List of comparisons
Eight studies met the inclusion criteria and reported on 3,811 infants who were cared for by attendants who wore or did not wear gowns.

PRIMARY OUTCOMES
Death before discharge (Table 01.01)
The death rate was reported in all the cluster allocation trials, each conducted in intensive care settings (Silverman 1967; Evans 1971; Agbayani 1981; Tan 1995; Pelke 1994). None of the trials found a statistically significant effect on death. The meta-analysis was confined to four trials (Silverman 1967; Evans 1971; Agbayani 1981; Tan 1995). Overall, not wearing a gown was associated with a trend towards reduction in death rate, [typical RR 0.84 (95% CI 0.70, 1.02)]; typical RD -0.03 (95% CI -0.05, 0.00)], but these results did not reach statistical significance. The death rate as reported by Pelke 1994 was similar between groups (0.44 per 100 patient days in the no gown periods and 0.51 per 100 patient days in the gown periods), but due to the way in which they were reported, these data could not be included in the meta-analysis.

Systemic nosocomial infection (Table 01.02)
Five cluster allocation trials reported information on systemic infection (septicaemia, meningitis, necrotizing enterocolitis, pneumonia), (Silverman 1967; Evans 1971; Agbayani 1981; Pelke 1994; Tan 1995). One of these (Silverman 1967), reported only meningitis or septicaemia confirmed by postmortem examination. None of the trials found a statistically significant effect on the incidence of systemic nosocomial infection. The meta-analysis, confined to four trials not including Pelke 1994, found no significant effect on systemic nosocomial infection, [typical RR 0.95 (95% CI 0.40, 2.23)]. Substantial heterogeneity was found in this comparison (I2= 57.1%) so a random effects model ws used for the meta-analysis. Pelke 1994 also provided data for systemic infections (no gowning period 1.38 infections per 100 patient days; gowning period 1.21 infections per 100 patient days); the difference was not statistically significant. Due to the way in which they were reported, the data of Pelke 1994 could not be included in the meta-analysis.

Localised nosocomial infection (Table 01.03)
Four studies were identified that evaluated localised nosocomial infection. Two were trials that randomised the individual patient (Forfar 1958; Rush 1990). These showed no statistically significant effect, [typical RR 1.17 (95% CI 0.74, 1.86)]. Two were cluster allocation trials (Evans 1971; Agbayani 1981). These also showed no significant effect on localised nosocomial infection, typical RR 1.29 (95% CI 0.84, 2.00). The overall estimate for the four studies showed no significant effect, [typical RR 1.24 (95% CI 0.90, 1.71)].
SECONDARY OUTCOMES
Colonisation
The methods used to collect and process swabs were similar, but the days on which swabs were taken varied between studies. Two of the trials limited their investigation to staphylococcal carriage (Forfar 1958; Rush 1990) and one to methicillin resistant Staphylococcus aureus carriage (MRSA) (Tan 1995). In the Tan 1995 study, the site of colonisation was not noted but carriage rates were similar between groups (no-gown group 4/1002 MRSA positive swabs, gown group 6/904 MRSA positive swabs).
Nasal colonisation (Table 01.04)
Nasal colonisation data was compared in six of the eight included studies. Three trials that randomised the individual patient (Forfar 1958; Birenbaum 1990; Rush 1990) found no significant differences in nasal colonisation rates, [typical RR 1.02 (95% CI 0.89, 1.18)]. There was also no significant effect seen in the two cluster trials (Evans 1971; Agbayani 1981), typical RR 0.91(95% CI 0.77, 1.07). When the results of all five trials were combined in an overall meta-analysis, there was no significant effect, [typical RR 0.98 (95% CI 0.88, 1.09)]. In the Pelke 1994 trial the number of swabs taken was used as the denominator with no indication of how many infants were swabbed. There were no significant differences in the rate of positive cultures between the no-gowning and gowning periods (no-gown group 179/375 positive swabs; gown group 208/351 positive swabs).
Umbilical colonisation (Table 01.05)
Six trials provided data on umbilical colonisation. Those randomising by individual (Forfar 1958; Birenbaum 1990; Rush 1990) showed no significant effect on this outcome [typical RR 1.03 (95% CI 0.93, 1.14)]. Results from two of the cluster allocation trials (Agbayani 1981; Evans 1971) also showed no significant difference on this outcome [typical RR 0.96 (95% CI 0.82, 1.12)]. When results from the five trials were combined, the result was not significant, [typical RR 1.01 (95% CI 0.93, 1.10)]. The other cluster allocation trial, Pelke 1994, reported similar proportions of positive cultures among the total cultures taken (no-gown group 92/213 positive swabs; gown group 86/167 positive swabs).

Eye colonisation (Table 01.06)
One study using random allocation by individual (Forfar 1958) collected data on eye colonisation. No significant difference was found between the no-gowned and gowned groups [RR 0.97 (95% CI 0.90, 1.05)].
Groin colonisation (Table 01.07)
One of the trials that randomised by individual, reported collected data on groin colonisation (Birenbaum 1990). Gowning policy did not significantly effect this outcome [RR 1.05 (95% CI 0.69, 1.57)].
Stool colonisation
In one study (Pelke 1994) there was a significant difference in the rate of stool colonisation between the no-gown (84/372) and the gown groups (48/346). A total of 718 cultures were taken from 230 infants, so it is unknown how many repeat cultures were taken from each infant with a positive culture result.
Cost
The cost of wearing gowns was estimated in three of the trials. Forfar 1958 included an estimate of the annual cost of gowning (nursing time, cost of gown laundering and maintenance) and calculated that the cost of time alone was equivalent to employing more than one full time equivalent nurse for one year. Tan 1995 compared the cost of gowns used in the no-gowning period with those used in the gowning period. During the gowning period, the average number of gowns used was 312 per day compared with 177 per day in the no-gowning periods. Gowns were defined as plastic aprons and cost Singapore $0.05 each. This resulted in a cost difference of S$1,696 per annum. Rush 1990 concluded that the projected annual cost savings associated with discontinuing gowns would be approximately $US 8,000 per annum.
Handwashing
One cluster allocation trial compared handwashing frequency between the no-gowning and gowning time periods (Pelke 1994). Direct observation at an infant's bedside three times weekly for 30 minutes was used to collect data. A sample of 87 contacts were observed in the no-gowning period and 34 infant contacts during the gowning period. The rate of hand wash compliance was similar in the two groups (no gowning 60%, gowning 62%, p = 0.84).
Length of hospital stay (Table 01.08)
Length of hospital stay in a well baby nursery was measured in three trials randomising the individual (Forfar 1958; Birenbaum 1990; Rush 1990). In the Rush 1990 study, hospital stay was similar in both groups, [MD 0.40 days (CI -5.82, 6.62)]. The number of in-patient days did not differ significantly in either the Forfar 1958 trial (no gown 9.0 days, gown 8.5 days) or the Birenbaum 1990 trial (no gown 2.81 days, gown 2.84 days). Standard deviations were unavailable for these two studies, preventing inclusion of these data in the outcome table.
ADDITIONAL OUTCOMES FOR PRETERM INFANTS
Duration of mechanical ventilation (Table 01.09)
One cluster allocation trial included results on the duration of mechanical ventilation (Tan 1995). The number of ventilator days was similar for infants admitted during the no-gowning and gowning time periods, [MD 5.00 days, (95% CI -11.09, 21.09)].
Duration of neonatal intensive care nursery stay
Pelke 1994 measured length of stay in a neonatal nursery environment. The mean length of stay between the no-gown and gown groups was not statistically different (no-gowning periods: mean number of days = 15; gowning periods: mean number of days = 20).
Antibiotic use in preterm infants
None of the trials provided data for this outcome
OTHER OUTCOMES

Nursery traffic
In a cluster allocation trial, Pelke 1994 used two 15-minute observation periods to monitor the number of people entering the nursery. The patterns of traffic were identical during the no-gown and gown periods with an average of 10 entries during each 15-minute observation period.
Post discharge follow-up
In the Birenbaum 1990 study, 83 from the no-gown group and 81 infants in the gown group were able to be followed up 4 weeks after discharge. Within this time, one infant from the no-gowning group was treated for conjunctivitis and one infant from the gowning group required hospitalisation for a viral infection.
SUBGROUP ANALYSIS
Effect by nursery type
All of the trials that randomised the individual patient were conducted in well-baby nurseries and all of the cluster allocation trials were undertaken in neonatal intensive care units. Thus, the analyses, sub-categories for trials randomising the individual are synonymous with well-baby nurseries and sub-categories for cluster allocation trials are synonymous with neonatal intensive care units.
Effect by gestational age at birth
We intended to investigate the effects of wearing gowns for subgroups of newborn infants by gestational age; however, none of the trials reported outcomes specifically by gestational age so this analysis could not be done.

Effect by visitors and attendants
There were no eligible studies reporting the independent effect of visitors or attendants wearing gowns on the study outcomes.

Discussion

Since overgowns are widely used in neonatal units, it was surprising that the evidence supporting their efficacy was limited. Of the eight studies meeting our inclusion criteria, three used the individual as the unit of allocation, but one of these did not describe the method used for allocation concealment. The nature of the study prevented blinding of the intervention and there was limited reporting of blinding of outcome assessment. Five of the studies had incomplete follow-up data on one or more of the outcomes (Forfar 1958; Evans 1971; Agbayani 1981; Rush 1990; Pelke 1994) and there was evidence of post-randomisation exclusions in one of the trials (Birenbaum 1990). Sample size calculations were absent in all but one study (Rush 1990).
Among the five cluster allocation trials there were a number of methodological variations that made comparisons difficult. In one study, colonisation rates were reported as outcomes per swab rather than per infant, leading to non-independence of multiple measures of the same outcome in the same patient. Similarly, the day on which swabs were routinely taken varied between studies. Rates of colonisation tend to increase with length of hospital stay, so comparing data on this outcome was not feasible unless swabs had been collected on the same postnatal day. Other data were reported as a rate per 100 days making it impossible to combine these results with other outcome data to estimate an overall effect. In addition, although techniques are now available for analysing cluster allocated studies, results were all analysed as if allocation was by individual, ignoring the cluster design and creating a potential to over-estimate the intervention effect. However, based on the consistency of findings between studies, the method of analysis is unlikely to have changed the primary results of this review.
There was little evidence in this review of either harm or benefit of overgown use when outcomes such as systemic infection, localised infection or colonisation were compared. The only important outcome that showed a strong trend in either direction was death before discharge, where the trend was towards a lower death rate among infants nursed in the non-gowning periods. The two studies contributing to the trend were conducted over 30 years ago when death rates in neonatal intensive care units were very high (Silverman 1967; Evans 1971). Both of the studies used a cluster design and analysed results as though allocation was by individual, which may have tended to overestimate treatment effect. In addition, overgowns were worn by attendants and visitors whenever incubator lids were open or if the infant was removed from the cot, making it unlikely that gowning could account for the observed differences. In the most recent and largest trial, no deaths were reported in either the gowning or no-gowning periods (Tan 1995). The one result that showed a significant difference when overgowns were worn or not worn by visitors and attendants was stool colonisation, with a reduction during gown periods. This result was flawed by the study methodology, where there was evidence of repeat measures on the same infant.
Other outcomes such as handwashing frequency, length of hospital stay, duration of mechanical ventilation and traffic in and out of the nursery were not significantly affected by overgown use. Based on these results and considering the costs associated with gowning, hospital personnel may wish to review their policies.
Heterogeneity effected one comparison, systemic infection. This may be explained by some of the issues outlined above, or because there was some variation in outcome when the older studies were compared with more recent investigations.
All the NICU studies included in this review used cluster allocation rather than allocating individual patients to the experimental and control groups. Allocation by cluster might be seen as a strength of study design for this question. It mirrors the way the intervention is offered in practice, and minimises contamination of the experimental and control groups. Secondary cases (of colonisation, infection, death) are included in the measure of effect. If a favoured policy is identified in such a study, the application of that result in practice would be to use the favoured policy in all babies, thus mimicking a cluster allocation design. However, future trials which use cluster allocation should use truly random methods for allocating by cluster, and should analyse the data taking into account the clustering of allocation.

Reviewers' conclusions

Implications for practice

This systematic review does not provide evidence that overgowns are effective in limiting infant colonisation, infection or death in newborn nurseries. Nor does gowning appear to impact on handwashing frequency. The costs associated with gowning are considerable.

Implications for research

In light of changes in hospital practices (such as rooming in, shortened length of stay and widespread discontinuation of overgown use) since many of the included studies were conducted, further investigations of the effect of overgowns on infection or colonisation rates in well-baby newborn nurseries appear to be unwarranted as their results would not be applicable to current practice.
The question of gowning in neonatal intensive care settings has not been tested using a randomised controlled design. Future investigations in this area should focus on important outcomes such as death and systemic infection using high quality randomised controlled designs of sufficient size to yield a conclusive result. Future studies that use cluster allocation should use truly random rather than quasi-random methods for allocating by cluster, and should analyse the data using methods which take into account the cluster design.

Acknowledgements

Potential conflict of interest

None

Characteristics of included studies

|Study |Methods |Participants |Interventions |Outcomes |Notes |Allocation |
| | | | | | |concealment |
|Agbayani 1981|Single centre |A total of 724 outborn |No gown: |1) Death before |This trail was |C |
| |cluster-allocation|(123) and inborn (601) |Hands and forearms |discharge |analysed as if | |
| |trial. |term and preterm |were washed with |2) Systemic |allocation was | |
| |Blinding of |infants. |povidone-iodine for|nosocomial |by individual. | |
| |randomisation: No.|A subgroup of 273 |two minutes. |infection, defined |It was unclear | |
| |Allocation |newborns who met the |Jewelry was removed|by documented |how all | |
| |occurred using a |following inclusion |from wrists and |sepsis, meningitis |infections were| |
| |pre-established |criteria were swabbed |fingers. Nurses |and necrotising |diagnosed. | |
| |list of 6 |for the presence of |wore scrub gowns. |enterocolitis. |Pathology | |
| |alternate 2 month |colonising bacteria. |Street clothes were|3) Localised |results were | |
| |blocks of gowning |Inclusion criteria: |worn by physicians,|nosocomial |available for | |
| |and modified |admitted to the NICU |other staff and |infection, defined |systemic | |
| |gowning over a |between Monday and |visitors. |as conjunctivitis, |infections but | |
| |12-month period. |Thursday who were less |Gown: |pustules and |not for | |
| |Blinding of |than 12 hours old and |As for no gown |abscesses. |localised | |
| |intervention: No. |who had negative blood |periods but gowns |4) Colonisation |infections. | |
| |Blinding of |cultures on admission. |were donned before |(prevalence of |Death, systemic| |
| |outcome |Infants who were |entering the |bacteria from the |and localised | |
| |assessment: |enrolled in the last 10|nursery. In both |nares, umbilicus |infection was | |
| |Unknown. |days of each two month |gown and no gown |and groin) amongst |reported for | |
| |Completeness of |interval were excluded.|groups, gowns were |the subgroup at 7 |the whole | |
| |follow-up: | |worn by anyone |different time |sample. | |
| |Complete for | |holding an infant. |points from day 1 |Colonisation | |
| |primary outcomes. | |Anterior nares, |to day 28. |data was | |
| |Incomplete for | |umbilicus and groin| |available for a| |
| |subgroup of 273 | |were swabbed on | |subgroup of 273| |
| |infants. | |admission to the | |infants. | |
| | | |nursery and on days| | | |
| | | |2,4,7,10,14,21 and | | | |
| | | |28 only among the | | | |
| | | |subgroup of | | | |
| | | |infants. | | | |
|Birenbaum |Single centre |Drawn from 1218 |No gown: |1) Nasal |Strong |A |
|1990 |randomised |deliveries with no |Attendants and |colonisation on |possibility of | |
| |controlled trial. |indication of how many |visitors washed |admission and on |post-randomised| |
| |Blinding of |were randomised. Study |their hands before |discharge |exclusions | |
| |randomisation: |outcomes were reported |entering the |2) Umbilical |(infants who | |
| |Yes. |for 202 infants. |nursery or mothers |colonisation on |did not have | |
| |Group assignment |Inclusion criteria: |room. Gowns were |admission and on |initial | |
| |from shuffled |(for 202 infants) |not worn when |discharge |cultures within| |
| |sealed envelopes |Admission to a |handling the |Any organic growth |6 hours of | |
| |that designated |combination of newborn |infant. |was considered to |delivery and | |
| |the gowning or no |nursery and rooming in |Gown: As for no |be a positive nose |those who did | |
| |gowning group. |care. |gowns except a gown|or umbilical |not have 4 | |
| |Blinding of |Exclusion criteria: |was worn for all |culture. |cultures | |
| |intervention: |Infants with mothers |infant related | |performed). | |
| |No |determined to be |procedures. | | | |
| |Blinding of |clinically unwell (e.g.|Routines in the | | | |
| |outcome assessment|defined by fever |nursery remained | | | |
| |: |chorioamnionitis and |unchanged. Four | | | |
| |Unknown. |premature or prolonged |swabs were taken | | | |
| |Completeness of |rupture of membranes), |from infants, two | | | |
| |follow-up: |infant requiring |within 6 hours of | | | |
| |Unknown. |intensive or |admission (nose and| | | |
| | |intermediate care, |umbilicus) and two | | | |
| | |infants for whom |on discharge. | | | |
| | |admission cultures were| | | | |
| | |not obtained within 6 | | | | |
| | |hours of delivery, and | | | | |
| | |infants who did not | | | | |
| | |have all admission and | | | | |
| | |discharge cultures | | | | |
| | |performed. | | | | |
|Evans 1971 |Single centre |604 preterm infants |No gown: Visitors |1) Death |This trial was |C |
| |cluster-allocation|admitted to the |and attendants did |2) Systemic |analysed as if | |
| |trial. |premature nursery. |not cover their |infection |allocation was | |
| |Blinding of |Inclusions: |outer clothing and |(pneumonia, |by individual. | |
| |randomisation: No.|Infants nursed in |nor did they wash |meningitis, sepsis)|The study was | |
| | |incubators |their hands before |3) Localised |interrupted in | |
| |Allocation was by |Exclusions: |entering the room. |infection |September, | |
| |alternating 2 or 3|Infants who were |Nurses wore the |(pyodermia, |during a | |
| |month periods (5 |severely ill (no |white uniforms used|conjunctivitis and |nongowning | |
| |separate gowning |definition provided). |to travel to the |diarrhea) |period, because| |
| |periods totalling | |hospital. Those |4) Colonisation of |of transfer of | |
| |11 months and 4 | |handling newborn |the nares and |the nursery to | |
| |separate | |infants through |umbilicus were |a new building.| |
| |non-gowning | |ports did not wear |reported at 7 time |It was unclear | |
| |periods totalling | |gowns but scrubbed |points from day 1 |how all | |
| |10 months). One | |for 3 minutes with |to 21 but were |infections were| |
| |month was excluded| |an antiseptic soap.|tabulated by day of|diagnosed. | |
| |from the study | |When infants were |life acquired and |Pathology | |
| |Blinding of | |removed from an |by species. No |results were | |
| |intervention: No | |isolette, or when a|overall prevalence |available for | |
| |Blinding of | |hood was opened, |by group was |systemic | |
| |outcome | |all persons in the |reported. |infections but | |
| |assessment: | |room wore a gown. | |not for | |
| |Unknown | |Gown: Attendants | |localised | |
| |Completeness of | |and visitors | |infections. | |
| |follow-up: unknown| |removed their outer| | | |
| | | |jackets, washed | | | |
| | | |their hands for 3 | | | |
| | | |minutes and donned | | | |
| | | |a gown before | | | |
| | | |entering the room. | | | |
| | | |Nurses changed into| | | |
| | | |scrub gowns at the | | | |
| | | |beginning of their | | | |
| | | |shift. | | | |
| | | |Both anterior nares| | | |
| | | |and the umbilicus | | | |
| | | |were swabbed 4 to 5| | | |
| | | |mornings weekly | | | |
| | | |until the infant | | | |
| | | |was transferred | | | |
| | | |from an incubator | | | |
| | | |to an open crib. | | | |
|Forfar 1958 |Single centre |167 infants admitted to|No gowns: |1) Localised |Infections were|B |
| |randomised |either of two newborn |No gowns or masks |nosocomial |assessed | |
| |controlled trial. |nurseries without |were worn by |infection, |clinically. If | |
| |Blinding of |rooming in facilities. |attendants or |diagnosed |possible, a | |
| |randomisation: |Inclusion criteria: |visitors. |clinically . |swab was taken | |
| |Unknown. |none documented. |Gown: Attendants |2) Nasal |from an | |
| |Infants were |Exclusion criteria: |and visitors |colonisation |infected lesion| |
| |allocated at |none documented. |observed a strict |3) Umbilical |but pathology | |
| |random to one of | |gowning and masking|colonisation |results were | |
| |two nurseries. No | |regime before |4) Eye colonisation|not reported. | |
| |description of the| |entering the |5) Length of stay | | |
| |process of random | |nursery. In |6) Nursing time | | |
| |allocation was | |addition, a |7) Cost | | |
| |documented. | |'personalised' | | | |
| |Blinding of | |gown, one for each | | | |
| |intervention: No | |baby was donned | | | |
| |Blinding of | |over the first | | | |
| |outcome | |gown, when handling| | | |
| |assessment: | |that infant. Gowns | | | |
| |Unknown. | |were changed every | | | |
| |Completeness of | |24 hours or when | | | |
| |follow-up: | |soiled. Staff were | | | |
| |Localised | |common to both | | | |
| |infection , yes. | |nurseries. | | | |
| |Colonisation, no | |For each baby, an | | | |
| | | |eye swab was taken | | | |
| | | |on the fourth day, | | | |
| | | |a nasal swab on the| | | |
| | | |eighth day and an | | | |
| | | |umbilical swab at | | | |
| | | |the time of | | | |
| | | |separation of the | | | |
| | | |cord. Swabs were | | | |
| | | |taken from infected| | | |
| | | |lesions if | | | |
| | | |possible. | | | |
| | | |Microbiological | | | |
| | | |examination was | | | |
| | | |limited to | | | |
| | | |staphylococcal | | | |
| | | |positive species. | | | |
|Pelke 1994 |Single centre |313 term and preterm |No gown: Nursing |1) Neonatal |This trial was |C |
| |cluster-allocation|infants admitted to the|staff wore scrub |mortality |analysed as if | |
| |trial: |Neonatal Intensive Care|suits, which were |2) Nasopharyngeal |allocation was | |
| |Blinding of |Unit |home -laundered and|colonisation |by individual. | |
| |randomisation: No.|Inclusion/exclusion |worn to the |3) Umbilical |Infection rates| |
| |Allocation was by |criteria: |hospital from home.|colonisation |and mortality | |
| |alternate 2-month |None documented |Other visitors and |3) Stool |were reported | |
| |gowning and no |A subgroup of 230 |staff wore their |colonisation |as 'rate per | |
| |gowning cycles (4 |infants (those who had |street clothes when|4) RSV |100 days'. | |
| |cycles over a |cultures taken) were |entering the NICU. |5) NEC |Information | |
| |period of 8 |studied. |Residents were the |6) Length of stay |about the | |
| |months). One | |only group who |7) Traffic flow |numerator and | |
| |entire 4 month | |continued to wear |8) Handwashing |denominator | |
| |period was | |hospital-laundered |compliance |were requested | |
| |repeated to | |scrubs and they | |but the author | |
| |eliminate the | |wore an over-gown | |could not | |
| |potential for | |when leaving the | |provide these | |
| |seasonal variables| |area. Gowns were | |details. | |
| |and outbreaks. | |available for | | | |
| |Blinding of | |parents to use when| | | |
| |intervention: No | |holding their | | | |
| |Blinding of | |infants but these | | | |
| |outcome | |were not used. | | | |
| |assessment: | |Gown: | | | |
| |Unknown | |Nursery staff | | | |
| |Completeness of | |changed into scrub | | | |
| |follow-up: | |dresses or suits | | | |
| |Unclear. The | |and covered these | | | |
| |number of cultures| |with a gown if they| | | |
| |exceeded the | |left the area. | | | |
| |number of infants | |Other visitors or | | | |
| |but it was unclear| |staff wore gowns | | | |
| |if all infants | |over their street | | | |
| |were swabbed. | |clothes when | | | |
| | | |entering the NICU. | | | |
| | | |Infants had | | | |
| | | |nasopharyngeal (or | | | |
| | | |tracheal aspirate | | | |
| | | |if intubated), | | | |
| | | |umbilical and | | | |
| | | |rectal or stool | | | |
| | | |swab taken weekly. | | | |
| | | |Nursery traffic was| | | |
| | | |monitored by | | | |
| | | |tallying the number| | | |
| | | |of people who | | | |
| | | |entered the NICU | | | |
| | | |during two | | | |
| | | |15-minute periods | | | |
| | | |per day on two days| | | |
| | | |per week. | | | |
| | | |Handwashing | | | |
| | | |compliance was | | | |
| | | |studied by 30 | | | |
| | | |minutes observation| | | |
| | | |by one infants | | | |
| | | |bedside three times| | | |
| | | |weekly. Bedside | | | |
| | | |areas were rotated | | | |
| | | |each week. | | | |
|Rush 1990 |Single centre |473 infants. Sample |No gown: |1) Nasal | |A |
| |randomised |drawn from 1130 infants|No cover gowns were|colonisation | | |
| |controlled trial: |consecutively admitted |worn by staff or |2) Umbilical | | |
| |Blinding of |to a newborn nursery. |visitors during any|colonisation | | |
| |randomisation: |Inclusions: >2500 |infant contact. |3) Colonisation of | | |
| |Yes, by sealed |grams, at least 37 |Gown: |nose and umbilicus | | |
| |envelope. |weeks gestation and |Staff and visitors |Clarification was | | |
| |Blinding of |Apgar at 5 minutes > 7 |wore cover gowns |requested and | | |
| |Intervention: No |at 5 minutes. |for all infant |received for | | |
| |Blinding of |Exclusions: infants |contact. In both |whether (i) all | | |
| |outcome: yes |initially admitted to |groups, staff |staff followed the | | |
| |Complete follow- |the NICU. |members, parents |protocol (ii) how | | |
| |up: No, due to | |and visitors |infections were | | |
| |culture reports | |continued to be |diagnosed and when,| | |
| |missing or | |advised to wash |(iv) clarification | | |
| |research staff | |their hands |of Table 2 and (v) | | |
| |unavailable to | |carefully before |how cost of gowns | | |
| |abstract data | |providing patient |was estimated | | |
| | | |care. | | | |
| | | |Nasal & umbilical | | | |
| | | |swabs were taken by| | | |
| | | |nursing staff on | | | |
| | | |the 3rd postnatal | | | |
| | | |day or before | | | |
| | | |discharge, | | | |
| | | |whichever was the | | | |
| | | |sooner. | | | |
|Silverman |Single centre |745 high risk infants |No gown: |1) Death |This trial was |C |
|1967 |cluster-allocation|admitted to the special|Outer coats were |2) Systemic |analysed as if | |
| |trial: |care nursery. Inclusion|not removed, nor |infection (included|allocation was | |
| |Blinding of |criteria: birthweight