According to research in the British Medical Journal the range of 'interventions' includes puncturing the skin to put in and take out tubes and drains, inserting catheters and removing large dressings.
In some cases, 'minor surgery' involving restitching surgical wounds or cutting out a piece of muscle tissue for analysis has also been undertaken without anaesthetic.
David Southall, professor of paediatrics at North Staffordshire Hospital, who led the research, said some of the children behaved as if they had been assaulted. 'You see a state of frozen watchfulness on their faces when doctors or nurses approach, which we recognise from children we know have been assaulted by their parents.'
He added: 'Babies and children under five are unable to express pain as adults or older children can. They can't say 'I want you to stop.' ' And some problems were practical. 'A toddler has pudgy hands. Trying to find a vein to insert a small tube can take 10 attempts.'
In the study at Royal Brompton Hospital, south-west London, about a third of the procedures witnessed were done without a pain reliever or sedative being given earlier. One child who had been in hospital for nearly a year, and also had severe learning difficulties, underwent 159 interventions likely to have been painful.
Nurses in the paediatric intensive care unit were asked to record every invasive procedure on babies aged, on average, one year and one month, and in hospital for more than three days. In all, 181 procedures were recorded on 55 babies - but case notes showed another 318 had been carried out.
Nurses' notes disclosed 49 per cent of the babies showed an 'adverse response'. Of those given no extra pain relief, 36 out of 50 grimaced or cried. Procedures took an average of five minutes, and a parent or relative was present for only 36 interventions.Reuse content