The very ink with which history is written is merely fluid prejudice. – Mark Twain
Ashok V, Bala I, Bharti N, Jain D, Samujh R. Effects of intraoperative liberal fluid therapy on postoperative nausea and vomiting in children—A randomized controlled trial. Pediatr Anesth. 2017;27:810-815. https://doi.org/10.1111/pan.13179
- Does intraoperative liberal fluid therapy with crystalloids affect post-operative nausea and vomiting (PONV) in children undergoing lower abdominal and penile surgery?
- Single centre, randomised trial
- Double blind computer generated randomisation to “restricted group” or “liberal group”
- Blinding of patients, parents, surgeons, Post- Anaesthesia Care Unit nurses and post-operative investigator
- Powered at 80% with sided alpha significance of 0.05
- Sample size calculated at 67 patients per group
- 150 patients enrolled to account for dropouts
- Single hospital in India
- Age 3-7 years
- ASA 1 or 2
- Elective lower abdominal and penile surgery of <60 minutes scheduled duration
- Antiemetic therapy within 24 hours before surgery
- Cardiovascular and renal disease
- Past history of PONV in patient, sibling and/or parent
- History of motion sickness,
- Obesity (BMI >30)
- Developmental delay
- Children whose parents could not be contacted by telephone
- Contraindication to caudal block
- 150 patients assessed for eligibility, nil excluded – 75 randomised and allocated to each group
- 145 patients completed study (3 lost to follow up in group 1, 2 lost to follow up in group 2)
- Baseline characteristics comparable between groups: age, weight, male:female, type and duration of surgery; heart rate, oxygen saturation and mean arterial pressure (data not provided).
Intervention and Control
- Restricted group – 10 ml/kg/hr dextrose-free Ringer’s lactate
- Liberal group – 30 ml/kg/hr dextrose-free Ringer’s lactate
Management common to both groups
- Premedication with oral midazolam
- Gas induction of sevoflurane in oxygen, maintenance of sevoflurane in 60% nitrous oxide in oxygen
- Caudal block with 0.75 ml/kg 0.25% plain bupivacaine
- IV fluid via infusion pump administered by non-blinded anaesthetist
- No intraoperative opioids, antiemetics or muscle relaxants
- Paracetamol IV at skin closure
- Ondansetron given at first episode of PONV
- Primary efficacy endpoint: no nausea or vomiting with no administration of any antiemetic medication during the 24 hours postoperatively
- All episodes of nausea, retching and emesis during 24 hours postoperatively
- Time to child asking for oral fluids
- Post-operative pain assessed using FLACC (face, legs, activity, cry, consolability) pain scale
- Parental satisfaction: 0-10: (0=completely unsatisfied; 10=completely satisfied)
- PONV was significantly less in liberal group [n= 20 (27.4%)] compared to the restricted group [n=33 (45.8%)]
(relative risk 0.59, 95% CI: 0.37-0.93, P=.021)
- Adjusted odds ratio of PONV liberal vs restricted group 2.24 (95% CI: 1.12-4.48, P=.022) after regression analysis
- NNT = 5.4
- Secondary findings
- Less thirst
- Overall better patient satisfaction
- Lower rates of antiemetic administration
No difference in analgesic requirement
- No evidence of adverse events including fluid overload and no significant difference in post-operative admission rates.
- The administration of 30 ml;/kg/hr intravenous fluid intraoperatively significantly reduces the incidence of PONV in children undergoing lower abdominal and penile surgeries.
- Children who received liberal fluids also had less thirst postoperatively, greater parental satisfaction with management of PONV symptoms
- Appropriate methodology for study question
- Successful randomisation with comparable groups
- Actual administered volume of fluids given to each group not defined
- In patients without risk factors for PONV undergoing short duration lower abdominal and penile surgery (<60 minutes) liberal fluid administration reduced post-operative nausea and vomiting when no prophylactic antiemetics were used, and reduced post-operative thirst.
- These findings are in keeping with other studies of the effect of fluid regimens upon PONV.
- Low NNT for benefit with low risks of harm due to the intervention.
- Non-administration of prophylactic anti-emetics is not routine practice in our institution.