Practice of immersion in hot water to relieve pain in neonatology: an integrative review.

The review combined different water techniques, including hydrotherapy, sponge bath, immersion bath, swaddled bath and first bath, so the results cannot be applied as one single intervention. Hydrotherapy studies included one uncontrolled clinical trial, quasi-experimental studies and an observational study, not randomised trials, and the authors say these results need caution. Pain relief was often a secondary outcome, and some studies focused on physical manipulation or body temperature rather than pain. The review did not report whether analgesics were given at the same time, or who carried out the intervention, which could affect outcomes. One hydrotherapy study had only 15 participants and found no pain-score improvement, although heart rate, respiratory rate and salivary cortisol fell. Pain scales depend on subjective assessment by health professionals, and lack of blinding can bias results. Swaddled bath combines immersion with swaddling or restraint, so the effect of immersion alone cannot be separated. Preterm newborns are more vulnerable to immersion because it can affect thermal protection, oxygen consumption and physiological parameters. The included studies assessed pain mainly during stressful or painful procedures. Pain caused by illness, such as respiratory problems, was a gap. Single short exposures were common, but hydrotherapy may need multiple sessions, so long-term effects are unknown.

Do not conclude that hot water immersion alone is proven to relieve newborn pain. The review mixed hydrotherapy, sponge baths and swaddled baths, one study found no pain-score improvement, and swaddled baths combine immersion with restraint, so the effect of any single component cannot be separated.