Supplemental Material 1 – Diagnosis and Resolution of PPOI
Diagnosis of PPOI
A definition of PPOI was recently proposed based on systematic review and global survey,
and was adopted for this study.1 PPOI was defined as occurring if patients met 2 or more of
the following 5 criteria on or after Day 4 post-operatively:

Nausea OR vomiting over the preceding 12 hours.
Nausea was graded as either mild, moderate or severe, or on a 0-10 Likert
scale (1-3 corresponding to mild; 4-7 moderate; and 8-10 severe). Patients
with nausea of moderate or severe intensity, or greater than 4/10 on a scale,
were classified as meeting this criterion.

Inability to tolerate a solid or semi-solid oral diet over the preceding two
mealtimes.
Patients were deemed to have met this criterion if they consumed less than
25% of their self-reported pre-operative meal quantity.

Abdominal distension.
This was clinician-defined as increased abdominal girth (from when patients
were examined pre-operatively) with tympany on percussion, and was graded
as mild, moderate or severe. Those identified as having moderate or severe
distension met this criterion.

Absence of flatus AND stool over the preceding 24 hours.
In patients with ileostomy or colostomy this was defined as the absence of air
or bowel contents in the stoma bag.

Radiologic evidence of ileus on abdominal plain film or CT over the preceding
24 hours.
Patients were deemed to have met this criterion if two or all three of the
following features were noted – gastric distension, presence of air-fluid levels,
and dilated small or large bowel loops without a transition point.
Resolution of PPOI
PPOI was defined as having resolved when all 4 of the following criteria were met:

Absence of nausea AND vomiting for 12 hours with nasogastric tube (NGT)
spigotted or removed.
‘Absence’ of nausea included that of mild intensity or ≤3/10 on a Likert scale.

Ability to tolerate a solid or semi-solid oral diet at the preceding mealtime.
More than 25% of self-reported pre-operative meal quantity was to have been
consumed to meet this criterion.

Absence of abdominal distension.
‘Absence’ of distension included those with clinician-determined mild
distension as described above.

Passage of flatus OR stool over the preceding 24 hours.
In participants with a stoma this was defined as the presence of air or bowel
contents in the stoma bag.
Supplemental Material 2 – Standardised management guidelines for PPOI
The clinical management of trial participants conformed to standardised evidence-based
recommendations as follows.2
A NGT was inserted if vomiting was a feature. This was initially set to free drainage, and
then spigotted with 6-hourly aspirates when output was less than 600mls/24 hours. When
output fell below 300ml/24 hours the NGT was removed.
Electrolytes (specifically sodium, potassium, magnesium and calcium) were monitored and
corrected on a daily basis.
Analgesia prescription was reviewed with weaning of opiates and progressive substitution
with regular paracetamol, regular tramadol and regular or as-required non-steroidal
inflammatory drugs. Opiates were reserved for breakthrough pain only.
Maintenance fluid therapy of Dextrose 4% and Saline 0.18% with KCl was prescribed at
1ml/kg/hr. NGT losses or vomits greater than 500mls were replaced ml for ml with 0.9%
Saline + 30mmol KCl at a maximum infusion rate of 330ml/hr. Fluid therapy in participants
with clinical dehydration, acute renal impairment, fluid overload or haemodynamic instability
was left to the discretion of the surgical team.
If feasible, patients were asked to ambulate at least three times a day with assistance as
necessary.
Parenteral nutrition (PN) was commenced if patients were unable to sustain adequate oral
intake for more than 7 days, or after 5 days if nutritionally deplete. PN was discontinued
when participants were tolerating an oral diet. The PN prescription was determined by the
nutritional support team.
Nursing and medical staff were made aware of the presence of these guidelines via formal
interactive ward-based teaching sessions and one-on-one reminders to involved personnel.
Additionally, a single-page summary of guidelines was placed in the clinical notes folder of
participants upon recruitment.
References
1.
2.
Vather R, Trivedi S, Bissett I. Defining postoperative ileus: results of a systematic review and
global survey. J Gastrointestin Surg 2013; 17:962-972.
Vather R, Bissett I. Management of prolonged post‐operative ileus: evidence‐based
recommendations. Aust N Z J Surg 2013; 83:319-324.