BACKGROUND Enteral nutrition is essential in the treatment of critically ill patients. Current methods to monitor enteral nutrition such as aspiration of residual volume may be inaccurate. Gastric ultrasonography estimates total gastric fluid volume using the Perlas model, but this model is validated for clear fluids only, and its accuracy for measuring thick fluids is unknown. OBJECTIVES The primary aim of this study was to evaluate the Perlas model for gastric volume estimation of enteral nutrition, a thick fluid product. DESIGN A single-centre, single blinded, randomised controlled study. SETTING Single university hospital, from May to July 2019. PARTICIPANTS Seventy-two healthy fasted volunteers were randomly allocated to different fluid volume groups. INTERVENTION Participants randomly ingested predetermined volumes between 50 and 400 ml of a feeding-drink (Nutricia Nutridrink). Following a standardised gastric ultrasound scanning protocol, a blinded sonographer measured the antral cross-sectional area in the supine and right-lateral decubitus positions. MAIN OUTCOME MEASURES Measurements were performed at baseline, 5 min postingestion and 20 min postingestion. Gastric volumes were predicted using the previously established Perlas model and compared with total gastric fluid volumes after ingestion of the study drink. RESULTS The Perlas model underestimated the volume of thick gastric fluid and yielded a suboptimal fit for our data. However, antral cross-sectional area and total gastric thick fluid volumes were significantly correlated (Pearson's correlation coefficient 0.73, P < 0.01). A new model was fitted to predict gastric volumes of thick fluids, using the antral cross-sectional area (cm2) in the right-lateral decubitus position: Volume (ml) = 79.38 + 13.32 x right-lateral cross-sectional area. CONCLUSION The Perlas model for clear gastric fluid volume estimation is suboptimal for thick fluid volume assessment and an alternative model is presented. CLINICAL TRIAL REGISTRATION Netherlands Trial Register Trial NL7677, Registration date: 16 April 2019; https://www.trialregister.nl/trial/7677.

Background Humanitarian healthcare workers are indispensable for treating weapon-wounded patients in armed conflict, and the international humanitarian community should ensure adequate preparedness for this task. This study aims to assess deployed humanitarian healthcare workers’ self-perceived preparedness, training requirements and mental support needs. Methods Medical professionals deployed with the International Committee of the Red Cross (ICRC) between October 2018 and June 2020 were invited to participate in this longitudinal questionnaire. Two separate questionnaires were conducted pre- and post-deployment to assess respondents’ self-perceived preparedness, preparation efforts, deployment experiences and deployment influence on personal and professional development. Results Response rates for the pre- and post-deployment questionnaires were 52.5% (114/217) and 26.7% (58/217), respectively. Eighty-five respondents (85/114; 74.6%) reported feeling sufficiently prepared to treat adult trauma patients, reflected by predeployment ratings of 3 or higher on a scale from 1 (low) to 5 (high). Significantly lower ratings were found among nurses compared to physicians. Work experience in a high-volume trauma centre before deployment was associated with a greater feeling of preparedness (mean rank 46.98 vs. 36.89; p = 0.045). Topics most frequently requested to be included in future training were neurosurgery, maxillofacial surgery, reconstructive surgery, ultrasound, tropical diseases, triage, burns and newborn noncommunicable disease management. Moreover, 51.7% (30/58) of the respondents regarded the availability of a mental health professional during deployment as helpful to deal with stress. Conclusion Overall, deployed ICRC medical personnel felt sufficiently prepared for their missions, although nurses reported lower preparedness levels than physicians. Recommendations were made concerning topics to be covered in future training and additional preparation strategies to gain relevant clinical experience. Future preparatory efforts should focus on all medical professions, and their training needs should be continuously monitored to ensure the alignment of preparation strategies with preparation needs.