Reproducibility of Ultrasound Blood Flow Measurement of the Superior Mesenteric Artery Before and After Exercise

Abstract

This study examines the reproducibility of gastro-intestinal blood flow measurements in the superior mesenteric artery (SMA) both before and immediately after exercise with Doppler ultrasound measurements. Twelve well-trained males (mean +/- SD: age 25.9 +/- 3.8 yr; VO2max 4.8 +/- 0.91 x min(-1)) were measured twice (trial 1 and 2) with a 1 week interval before and immediately after 1 hr cycling at 70% VO2max. Duplex scanning was performed with the athletes in supine position immediately after transition from a chair (before exercise) or bicycle (after exercise). The variability of three measurements before exercise was studied within both trials (short-term reproducibility) and the mean pre-exercise values were compared between the trials (long-term reproducibility). In addition, post-exercise measurements were compared in the same way. Reproducibility was tested using the coefficient of variation and Cronbach's alpha. Mean pre-exercise blood flow was 424 +/- 66 ml/min (n = 12) in trial 1 and 375 +/- 38 ml/min (n = 11) in trial 2. Immediately after exercise blood flow had decreased by 49% to 214 +/- 36 ml/min (p <0.01) in trial 1 and by 38% to 234 +/- 36 ml/min (p < 0.01) in trial 2. Blood flow before and after exercise was not significantly different between trials (paired t-test) and therefore reproducible at the group level. Before exercise a good to fair reproducibility was observed both at the short-term (Cronbach's alpha: 0.88 in trial 1, 0.73 in trial 2, n = 11), and at the long-term (alpha = 0.80, n= 11). In contrast, long-term reproducibility immediately after exercise was poor (alpha = -0.99, n = 8 and alpha = 0.36, n = 7 after the first and second cycling period, respectively). In conclusion, duplex scanning of SMA after a sitting-supine transition in well-trained subjects is not a reproducible method at the individual level for intestinal blood flow measurements immediately after exercise.

Prevalence of Diarrhea and Enteropathogens in Racing Sled Dogs

“…Proposed etiologies for gastrointestinal dysfunction associated with running include gastrointestinal ischemia, the actions of GI hormones and neuropeptides released during exercise, endotoxemia, mechanical stimulation or trauma to the bowel, and exercise induced alterations of colonic motility 26,28,29 . Exercise, even at moderate intensity, can significantly reduce splanchnic blood flow, which may have consequences for mucosal integrity and intestinal contractility 30,31 . A recent study demonstrated mucosal destruction and altered intestinal contractility in a murine model of repetitive treadmill running 32 .…”

Systematic review: the impact of exercise on mesenteric blood flow and its implication for preoperative rehabilitation

“…Duration of exercise was indeed more prolonged in these studies, ranging from 12 to 30 min. Two studies also used direct measurement of the SMA to provide flow rates [38, 39]. The reproducibility of Eriksen’s findings has not been established in a study using similar duration, intensity and type of exercise.…”

Triggering for Submaximal Exercise Level in Gastric Exercise Tonometry: Serial Lactate, Heart Rate, or Respiratory Quotient?

“…Although data on the splanchnic vascular responses to maximal exercise have not been established, ischemia has been established frequently in these circumstances [3, 7]. In a study on splanchnic blood flow in trained volunteers, mean superior mesenteric artery blood flow fell by 38–49% after a 10-min exercise test at 70% of maximal workload [8]. It has been shown that the flow reduction in the celiac artery exceeds that of the superior mesenteric artery but still does not exceed about 50% [9].…”