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Clinical Guidelines (Nursing)

Environmental humidity for premature neonates

  • Introduction

    Infants born at <30 weeks gestation have an immature epidermis and stratum corneum and are at an increased risk of transepidermal water loss (TEWL).  The use of environmental humidity assists to reduce TEWL and in turn supports temperature regulation, fluid and electrolyte management and skin integrity.


    The aim of this guideline is to provide all clinical staff with the criteria, settings and weaning regime required for the provision of environmental humidity for preterm infants.  Correct management of environmental humidity assists to improve skin integrity, thermoregulation and fluid and electrolyte balance. 

    Definition of terms

    • Environmental humidity: The concentration of water vapour in the air surrounding the neonate.
    • Transepidermal water loss (TEWL): The evaporative loss of water from the immature epidermal layer of the premature infant’s skin. 
    • Hybrid: A hybrid cot operates as an incubator, with the ability to raise the hood and function as an open-system radiant warmer. This cot is beneficial for premature infants who are best suited to being nursed in an incubator, where there is indication for frequent access or surgery that necessitates an ability to provide open-system care.
    • Incubator: Incubators are utilised to provide a controlled, enclosed heated environment to ensure neutral thermoregulation is provided, enabling the infant to be nursed unwrapped. 
    • Servo Control: Heat output is automatically and constantly adjusted according to the programmed set skin temperature, which is continuously measured from the skin temperature probe. This is the preferred mode of applying thermoregulatory assistance to most neonates, but requires close monitoring and assessment of probe site.
    • Radiant Warmer: Radiant warmers are an open care cot system designed to provide thermal stability to infants while allowing for continuous direct observation and accessibility. As this is not an enclosed system the temperature will fluctuate depending on the surrounding environment.


    All neonates <30 weeks gestation AND <2 weeks of age should be nursed in an incubator with environmental humidity and servo control thermoregulation functions.    

    • Four hourly axillary temperatures 
    • On commencing environmental humidity, perform hourly until stable
    • Increase frequency if outside of normothermia
    • An accurate fluid balance should be monitored and recorded.




    Environmental humidity should be delivered via an incubator, and commenced as soon as practical following admission.  The water reservoir within the incubator should be filled with sterile water to prevent bacterial colonisation, and regularly checked and refilled as required.  Gradual weaning should occur with staged reductions in the humidity percentage after 7 days of life as long as this is clinically appropriate. 

    Hybrid Incubator (Baby Leo)

    A water bag needs to be attached to the humidification system with the connection kit via the leur lock on the rear sensor wall.  On the babyLeo, humidity therapy control should be set manually in the therapy bar (see table below). 

    Radiant Warmer

    While it is possible to provide a degree of humidification while nursed on a radiant warmer, there is a significant increase in TEWL.  Furthermore, this method poses potential problems regarding an accumulation of carbon dioxide for non-ventilated infants.  If patient requires surgery, the humidity can be turned off and the hood in the hybrid warmer can be lifted up. 


    How to set up humidity in an incubator How to set up humidity on Babyleo 


    The impact of TEWL and serum sodium levels should be regularly assessed, by testing for hypernatraemia as an indicator of excessive TEWL or water deficit, this signifies a necessity for higher humidification percentages in the incubator.  

    Day of Life Environmental Humidity (%)
    1-7 80%
    8 75%
    9 70%
    10 65%
    11 60%
    12 55%
    13 50%
    14 45%
    15 CEASE


    After successful staged reductions, environmental humidity can then be ceased after 2 weeks of life, as the epidermis will then have matured to act as an effective barrier.  The table below demonstrates the commencing and weaning process for humidification.   

    It is important to note that the duration and percentage of environmental humidity may vary and depends on the neonate’s gestational age, serum sodium levels, fluid balance and skin condition – all of which should be discussed and assessed during the medical ward round. Weaning humidity should only continue when clinically indicated as appropriate. 


    Within the flowsheets of EMR, within the observation section, the following should be documented:

    • Hourly set and actual environmental humidity levels (%)
    • Hourly set and actual servo control temperature as well as documentation about location of servo probe
    • Four hourly axillary temperatures 
      • On commencing environmental humidity, perform hourly until stable
      • Increase frequency if outside of normothermia
      • Accurate fluid balance should also be recorded within the flowsheets

    Nursing Care 

    • Once humidification has been ceased, change the incubator or hybrid cot, to prevent microbial build up. 
    • If using and incubator, remove the water and the humidity chamber should be sent to CSSD. The heater unit is to be processed by the Butterfly Ward PSA's (with care taken when removing the heater unit as it may still be hot). 
    • Cleaning staff need to know whether humidification has been run when using the hybrid cot. Nursing staff should put a sign on the incubator when moving to the cleaning room so that additional cleaning can be undertaken appropriately
    • Take care to circumvent excess rain-out by wiping the inside of the incubator with a dry cloth.
    • On the hybrid cots there is a clear view button which can be utilised to reduce condensation on the inside of the hood.
    • Nursing staff should take care to check the position of the probe site at the start of the shift, change the position once per shift, and check for pressure areas. This will ensure that servo control runs without causing problems with temperature instability due to incorrect or invalid temperatures being monitored. 

    Special Considerations

    • Minimise the opening of doors so that humidity inside incubator remains constant.
    • The hybrid cots have an “air curtain” to minimise heat lost while portholes open, although 
    • It is still important to consider clustering cares and minimal handling for all preterm infants
    • Change the incubator weekly.  Document this date both within EMR, and by placing a sign on the cot. 

    Family Care

    • The requirement of environmental humidity in care of a neonate who is haemodynamically stable does not exclude them from participating in skin-to-skin care (SSC). The potential increase in TEWL during SSC is minimal and transpires to negligible clinical importance.
    • Ensure families understand the rationale for environmental humidity and facilitate and encourage interaction with their newborn where able.



    • Allwood, M (2011), ‘Skin Care Guidelines for Infants Aged 23-30 Weeks’ Gestation: a Review of the Literature’, Neonatal Paediatric and Child Health Nursing, 14(1): 20-27.
    • Argen, J, Sjors, G & Sedin, G (2006), ‘Ambient Humidity Influences the Rate of Skin Barrier Maturation in Extremely Preterm Infants’, The Journal of Pediatrics, 148(5): 613-617.
    • Deguines C, et al., 2012, ‘Variations in incubator temperature and humidity management: a survey of current practice’, Acta Paediatrics; 101:230-235.
    • Fanaroff, A.A. Fanaroff, J.M. (2013). Klaus & Fanaroff’s Care of the High-Risk Neonate. (6th ed). Philadelphia: Elsevier Saunders. 
    • Eastern Regional Neonatal Benchmarking Group. Humidity for infants < 30 weeks gestation. Clinical Guideline. February 2006 
    • Fidler, H. (2011). Incubator Humidity. Advances in Neonatal Care, 11(3), pp.197-199.
    • Flenady, V & Woodgate, PG (2009), ‘Radiant Warmers versus Incubators for Regulating Body Temperature in Newborn Infants (Review)’, The Cochrane Collaboration, Wiley Publishers.
    • Gomella, T & Cunningham, M (2013), ‘Management of the Extremely Low Birthweight Infant during the First Week of Life’, (pp163-174), Neonatology: Management, Procedures, On-Call Problems, Diseases and Drugs, 7th edition, McGraw-Hill Education, USA.
    • Mercy Hospital for Women Clinical Guideline (2019), ‘Incubator Humidification for Neonates Procedure’. 
    • Royal Women’s Hospital Clinical Guideline (17th May, 2016), ‘Ambient Humidity in NICU’. 
    • Sinclair, L & Sinn, J (2009), ‘Higher versus Lower Humidity for the Prevention of Morbidity and Mortality in Preterm Infants in Incubators’, Intervention Protocol, Cochrane Neonatal Group.
    • Sherman, T., Greenspan, J., St. Clair, N., Touch, S. and Shaffer, T. (2006). Optimizing the Neonatal Thermal Environment. Neonatal Network, 25(4), pp.251-260.
    • Wada, M., Kusuda, S., Takahashi, N. and Nishida, H. (2008). Fluid and electrolyte balance in extremely preterm infants <24 weeks of gestation in the first week of life. Pediatrics International, 50(3), pp.331-336.

    Evidence table

    Environmental humidity for premature neonates evidence table

    Please remember to read the disclaimer

    The development of this nursing guideline was coordinated by Emily Dam, RN/RM, Butterfly Ward, and approved by the Nursing Clinical Effectiveness Committee. Updated May 2020.