L. Bubb, K. Gillespie, R. Goel, J. Keough

Alder Hey Children's NHS Foundation Trust, UK


Alder Hey provides cleft surgery to paediatric patients as part of the Northwest, Isle of Man and North Wales Cleft Lip and Palate Network.

Children routinely receive paracetamol as part of their anaesthetic with the route of administration at the discretion of the anaesthetist; an oral dose pre-operatively or either a rectal or intravenous (IV) dose intra-operatively.  Given recent shortages of IV paracetamol preparations necessitating increased use of enteral doses, we were keen to see whether this impacted the post-operative course for our cleft patients.  This was part of a wider evaluation  of anaesthesia for cleft procedures at Alder Hey.


We retrospectively audited the electronic records of 112 children undergoing cleft surgery at Alder Hey in 2023.  Data on anaesthetic technique including route of paracetamol administration and a range of outcome measures, including the time to first oral intake, length of hospital stay and post-operative morphine and antiemetic requirements was collected.


64 patients undergoing cleft surgery procedures received their perioperative paracetamol as an IV dose and 48 received it enterally (11 orally and 37 rectally).  Most individual procedures had insufficient numbers for subgroup analysis, however we were able to analyses those undergoing cleft palate surgery (n=40), of whom 21 received an enteral dose (all rectal) and 19 received IV.

Across all procedures, there was a statistically significant increase in  post-operative day (POD) 1 morphine requirements and total post-operative morphine dosing.  There were no significant differences in any other assessed outcome measures including POD 0 morphine requirements.

Within the cleft subgroup analysis there were no significant differences in any of the assessed outcome measures we assessed.


Given that the plasma half-life of paracetamol ranges is 1.9-2.5 hours1, the increase in POD 1 and total dose of morphine following enteral paracetamol are interesting findings. One potential explanation is a delay in patients receiving their second dose of paracetamol following a rectal dose due to unfamiliarity with safe dosing intervals when the rectal route is used.

Furthermore, the population covers a diverse group of procedures and patients and hence there are likely to be confounders which could contribute to this association, such as adjuvant analgesic drug use  and choice of TIVA or volatile anaesthetic technique.  There was also a small increase in POD 1 morphine requirements in the cleft palate subgroup, however this was not statistically significant.

In conclusion, recognising this is a small single-centre study, our results suggest that in our institution IV paracetamol may reduce post-operative opioid requirements compared to enteral Paracetamol. However, there are no major differences in other outcomes including time to first intake and length of stay.


  1. Forrest JA, Clements JA, Prescott LF. Clinical pharmacokinetics of paracetamol. Clin Pharmacokinet. 1982;7: 93-107.
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