Bedside breath tests in children with abdominal pain: a prospective pilot feasibility study

Background: There is no definitive method of accurately diagnosing appendicitis before surgery. We evaluated the feasibility of collecting breath samples in children with abdominal pain and gathered preliminary data on the accuracy of breath tests. Methods: We conducted a prospective pilot study at a large tertiary referral paediatric hospital in the UK. We recruited 50 participants with suspected appendicitis, aged between 5 and 15 years. Five had primary diagnosis of appendicitis. The primary outcome was the number of breath samples collected. We also measured the number of samples processed within 2 h and had CO2 ≥ 3.5%. Usability was assessed by patient-reported pain pre- and post-sampling and user-reported sampling difficulty. Logistic regression analysis was used to predict appendicitis and evaluated using the area under the receiver operator characteristic curve (AUROC). Results: Samples were collected from all participants. Of the 45 samples, 36 were processed within 2 h. Of the 49 samples, 19 had %CO2 ≥ 3.5%. No difference in patient-reported pain was observed (p = 0.24). Sampling difficulty was associated with patient age (p = 0.004). The logistic regression model had AUROC = 0.86. Conclusions: Breath tests are feasible and acceptable to patients presenting with abdominal pain in clinical settings. We demonstrated adequate data collection with no evidence of harm to patients. The AUROC was better than a random classifier; more specific sensors are likely to improve diagnostic performance. Trial registration: ClinicalTrials.gov, NCT03248102. Registered 14 Aug 2017

Abdominal pain and two x-rays: spot the difference

We present two patients with air found in the right upper quadrant on standard abdominal x-ray. One was diagnosed with pneumobilia and underwent elective surgery for a bilioenteric fistula. The other was diagnosed with portal vein gas and underwent an emergency exploratory laparotomy at which a superior mesenteric artery embolism was found. The differential diagnostic criteria for pneumobilia and portal vein gas are described. If portal venous gas is found on x-ray in patients with abdominal pain, it is recommended that management is aggressive, meaning an emergency exploratory laparotomy, because mortality in such cases is approximately 75%. </jats:p