Internet-Based Resources Frequently Provide Inaccurate and Out-of-Date Recommendations on Preoperative Fasting: A Systematic Review.

Roughead, T. et al. Anesthesia & Analgesia. Published online: September 16 2016


Preoperative fasting is important to avoid morbidity and surgery delays, yet recommendations available on the Internet may be inaccurate. Our objectives were to describe the characteristics and recommendations of Internet resources on preoperative fasting and assess the quality and readability of these websites.

We searched the Internet for common search terms on preoperative fasting using Google(R) search engines from 4 English-speaking countries (Canada, the United States, Australia, and the United Kingdom). We screened the first 30 websites from each search and extracted data from unique websites that provided recommendations on preoperative fasting. Website quality was assessed using validated tools (JAMA Benchmark criteria, DISCERN score, and Health on the Net Foundation code [HONcode] certification). Readability was scored using the Flesch Reading Ease score and Flesch-Kincaid Grade Level.

A total of 87 websites were included in the analysis. A total of 48 websites (55%) provided at least 1 recommendation that contradicted established guidelines. Websites from health care institutions were most likely to make inaccurate recommendations (61%). Only 17% of websites encouraged preoperative hydration. Quality and readability were poor, with a median JAMA Benchmark score of 1 (interquartile range 0-3), mean DISCERN score 39.8 (SD 12.5), mean reading ease score 49 (SD 15), and mean grade level of 10.6 (SD 2.7). HONcode certification was infrequent (10%). Anesthesia society websites and scientific articles had higher DISCERN scores but worse readability compared with websites from health care institutions.

Online fasting recommendations are frequently inconsistent with current guidelines, particularly among health care institution websites. The poor quality and readability of Internet resources on preoperative fasting may confuse patients.

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Black or white coffee before anaesthesia?: A randomised crossover trial

Larsen, B. et al. European Journal of Anaesthesiology. June 2016. 33 (6). pp. 457–462

Image source: kate mccarthy // CC BY-ND 2.0

Background: In current preoperative fasting guidelines, coffee with milk is still regarded by many as solid food. Evidence on the consequences for gastric volume of adding milk to coffee 2 h before anaesthesia is still weak.

Objectives: The aim of this study was to compare the gastric volume by MRI in healthy volunteers after drinking coffee with and without added milk.

Design: A randomised crossover trial where all participants were exposed to three coffee and milk mixtures performed as a noninferiority study with a predefined noninferiority limit of 12 ml.

Setting: Department of Day Surgery and Department of Radiology, Aarhus University Hospital, Aarhus, Denmark. The study was conducted between August 2013 and February 2014.

Participants: Total 32 healthy volunteers, aged 18 to 71 years.

Interventions: The participants fasted for 6 h for solid food, and 2 h before the MRI examination of gastric volume, each participant ingested one of three coffee mixtures: 175 ml coffee, including either 0 or 20 or 50% full fat milk. Each participant was studied by MRI three times separated by a minimum time interval of 2 days. The order of coffee mixture ingested was determined by random allocation.

Main Outcome Measure: Gastric volume as measured by MRI.

Results: The mean gastric volume for black coffee was 27.8 ml, for coffee with 20% milk 17.9 ml and for coffee with 50% milk 20.6 ml. Compared to black coffee, the gastric volume for 20% milk was significantly decreased with a difference of −10.0 ml (95% confidence interval, −18.2, −1.8), and for 50% milk it was insignificantly decreased, −7.2 ml (95% confidence interval, −17.4, +2.9). The upper confidence interval for the difference in gastric volume between the ‘no milk added’ group and each ‘milk added’ group did not reach the noninferiority limit of 12 ml.

Conclusion: The study provides evidence that adding up to 50% full fat milk to coffee leads to no or only a minimal increase of the gastric volume 2 h later. The results support a liberalisation of policy on the addition of milk to hot drinks before planned anaesthesia.

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