Impact of clear fluid fasting on pulmonary aspiration in children undergoing general anesthesia: Results of the German prospective multicenter observational (NiKs) study.

BACKGROUND: A preliminary national audit of real fasting times including 3324 children showed that the fasting times for clear fluids and light meals were frequently shorter than recommended in current guidelines, but the sample size was too small for subgroup analyses. AIMS: Therefore, the primary aim of this extended study with more participating centers and a larger sample size was to determine whether shortened fasting times for clear fluids or light meals have an impact on the incidence of regurgitation or pulmonary aspiration during general anesthesia in children. The secondary aim was to evaluate the impact of age, emergent status, ASA classification, induction method, airway management or surgical procedure. METHODS: After the Ethics Committee's approval, at least more than 10 000 children in total were planned to be enrolled for this analysis. Patient demographics, real fasting times, anesthetic and surgical procedures, and occurrence of target adverse events defined as regurgitation or pulmonary aspiration were documented using a standardized case report form. RESULTS: At fifteen pediatric centers, 12 093 children scheduled for surgery or interventional procedures were included between October 2018 and December 2019. Fasting times were shorter than recommended in current guidelines for large meals in 2.5%, for light meals in 22.4%, for formula milk in 5.3%, for breastmilk in 10.9%, and for clear fluids in 39.2%. Thirty-one cases (0.26%) of regurgitation, ten cases (0.08%) of suspected pulmonary aspiration, and four cases (0.03%) of confirmed pulmonary aspiration were reported, and all of them recovered quickly without any consequences. Fasting times for clear fluids shortened from 2 hours to 1 hour did not affect the incidence of adverse events (upper limit 95% CI 0.08%). The sample size of the cohort with fasting times for light meals shorter than 6 hours was too small for a subgroup analysis. An age between one and 3 years (odds ratio 2.7,95% CI 1.3 to 5.8%; P < .01) and emergent procedures (odds ratio 2.8,95% CI 1.4 to 5.7;P < .01) increased the incidence of adverse events, whereas ASA classification, induction method, or surgical procedure had no influence. The clear fluid fasting times were shortest under 6/4/0 as compared to 6/4/1 and 6/4/2 fasting regimens, all with an incidence of 0.3% for adverse events. CONCLUSION: This study shows that a clear fluid fasting time shortened from 2 hours to 1 hour does not affect the incidence of regurgitation or pulmonary aspiration, that an age between one and 3 years and emergent status increase the incidence of regurgitation or pulmonary aspiration, and that pulmonary aspiration followed by postoperative respiratory distress is rare and usually shows a quick recovery.

Real fasting times and incidence of pulmonary aspiration in children: Results of a German prospective multicenter observational study.

BACKGROUND: Prolonged fasting before anesthesia is still common in children. Shortened fasting times may improve the metabolic and hemodynamic condition during induction of anesthesia and the perioperative experience for parents and children and simplify perioperative management. As a consequence, some centers in Germany have reduced fasting requirements, but the national guidelines are still unchanged. AIMS: This prospective multicenter observational study was initiated by the Scientific Working Group for Pediatric Anesthesia of the German Society of Anesthesiology and Intensive Care Medicine to evaluate real fasting times and the incidence of pulmonary aspiration before a possible revision of national fasting guidelines. METHODS: After the Ethics Committee's approval, at least 3000 children were planned to be enrolled for this analysis. Patient demographics, real fasting times, anesthetic and surgical procedures and occurrence of regurgitation or pulmonary aspiration were documented using a standardized case report form. Results were presented as median [interquartile range] (range) or incidence (percentage). RESULTS: At ten pediatric centers, 3324 children were included between October 2018 and May 2019. The real fasting times for large meals were 14 [12.2-15.6] (0.5-24) hours, for light meals 9 [5.6-13.3] (0.25-28.3) hours, for formula milk 5.8 [4.5-7.4] (0.9-24) hours, for breast milk 4.8 [4.2-6.3] (1.3-25.3) hours and for clear fluids 2.7 [1.5-6] (0.03-22.8) hours. Prolonged fasting (deviation from guideline >2 hours) was reported for large meals in 88.3%, for light meals in 54.7%, for formula milk in 44.4%, for breast milk in 25.8% and for clear fluids in 34.2%. Eleven cases (0.33%) of regurgitation, four cases (0.12%) of suspected pulmonary aspiration and two cases (0.06%) of confirmed pulmonary aspiration were reported; all of them could be extubated after the end of the procedure and recovered without any incidents. CONCLUSION: This study shows that prolonged fasting is still common in pediatric anesthesia in Germany that pulmonary aspiration with postoperative respiratory distress is rare and that improvements to current local fasting regimens and national fasting guidelines are urgently needed.

Fibre type related changes in the metabolic profile and fibre diameter of human vastus medialis muscle after anterior cruciate ligament rupture.

Vastus medialis muscles of patients with chronic anterior instability of the knee after anterior cruciate ligament rupture were analysed to investigate changes in defined muscle fibres of the diseased leg in comparison to the healthy leg of the same patient. Metabolic and morphological parameters were obtained by cytophotometrical measurements of the activities of succinate dehydrogenase (a marker of oxidative metabolism) and glycerol-3-phosphate dehydrogenase (a marker of glycolytic metabolism) of slow-oxidative (SO), fast-oxidative glycolytic (FOG) and fast-glycolytic (FG) fibre types in serial sections and by measuring the minimal fibre diameters of type I (slow) and type II (fast) fibres. We found decreased glycolytic activity and a shift to more oxidative metabolism in each fibre type suggesting diminished fast force and shift to endurance force development. The latter was interpreted as a sign of active compensation for the knee instability. Significantly decreased minimal fibre diameters to 85.9% in type I fibres, and to 88.7% in type II fibres of the diseased muscle were measured, indicating the fibre atrophy. Our findings suggest that the atrophied muscle fibres of the affected vastus medialis muscle adapt to the altered conditions by changing their metabolic profile. Muscle fibres of different types were found to be affected similarly.