Comparison of bolus remifentanil versus bolus fentanyl for blunting cardiovascular intubation responses in children： a randomized, double-blind study

Background The authors found no study to compare the efficacy of bolus dose fentanyl and remifentanil blunting the cardiovascular intubation response in children, so they designed this randomized, double-blind clinical study to assess the effects of remifentanil 2 μg/kg and fentanyl 2 μg/kg by bolus injection on the cardiovascular intubation response in healthy children.Methods One hundred and two children, the American Society of Anesthesiologists （ASA） physical status 1-2 and scheduled for elective plastic surgery under general anesthesia, were randomly divided into one of two groups to receive the following treatments in a double blind manner： remifentanil 2μg/kg （Group R） and fentanyl 2 μg/kg （Group F） when anesthesia was induced with propofol and vecuronium. The orotracheal intubation was performed using a direct laryngoscope. Blood pressure （BP） and heart rate （HR） were recorded before anesthesia induction （baseline values）, immediately before intubation, at intubation and every minute for 5 minutes after intubation. The percent changes of systolic blood pressure （SBP） and HR relative to baseline values and the rate pressure product （RPP） at every observing point were calculated. The incidences of SBP and HR percent changes 〉30% of baseline values and RPP 〉22 000 during the observation were recorded.Results There were no significant differences between groups in the demographic data, baseline values of BP and HR and the intubation time. As compared to baseline values, BP, HR and RPP at intubation and their maximum values during observation increased significantly in Group F, but they all decreased significantly in Group R. BP, HR and RPP at all observed points, and their maximum values during the observation, were significantly different between groups. There were also significant differences between groups in the percent change of SBP and HR relative to baseline values at all observed points and their maximum percent changes during the observation. The incidences of SBP and HR percent increased 〉30% of the baseline values and RPP 〉22 000 during the observation, were significantly higher in Group F than in Group R, but the incidences of SBP and HR percent decreased 〉30% of baseline values were significantly lower in Group F compared with Group R.Conclusions When used as part of routine anesthesia induction with propofol and vecuronium in children, fentanyl 2 μg/kg by bolus injection fails to effectively depress the cardiovascular intubation response. Remifentanil 2 μg/kg by bolus injection can completely abolish the cardiovascular intubation response, but also cause more adverse complications of temporary siclnificant cardiovascular depression.

Comparison of Cardiovascular Parameters and Internal Training Load of Different 1-h Training Sessions in Non-elite CrossFit^(®)Athletes

Purpose The fact that CrossFit^(®)is the best-known and rapidly growing concept for high-intensity interval training(HIIT)and high-intensity functional training(HIFT)results in a continuous increase of athletes performing CrossFit^(®).In the more than 15,000 CrossFit^(®)Affiliates worldwide,the training concept is usually offered in 1-h training sessions containing the CrossFit^(®)-related workout of the day(WOD),as well as a general warm-up,movement demonstrations,and skill training.Here,we report how physiological parameters measured by heart rate(HR)values vary during four different 1-h CrossFit^(®)training sessions of non-elite athletes(n=27)in a local affiliated training center and what influencing factors may exist.Methods The duration of the 1-h training sessions were divided into a warm-up part(WU-part),a skill development part combined with strength exercises(A-part),followed by the WOD part(B-part).Results Analysis of HR values shows high training intensity(≥91%HR_(max))not throughout the duration of each training session,only during B-part.The mean HR values in B-part differ significantly compared to the remaining training parts(P<0.001)for all four training sessions.Comparison of different CrossFit^(®)experience levels revealed no significant differ-ence in acute physiological demands and training load between beginner and experienced CrossFit^(®)athletes.Conclusion Our results may suggest that practicing CrossFit^(®)in 1-h training sessions combined anaerobic and aerobic exercise intensities,with the training concept allows beginners and experienced athletes to be trained with the same cardio-vascular responses and training intensities.