The impact of venous occlusion per se on forearm muscle blood flow: implications for the near‐infrared spectroscopy venous occlusion technique

Abstract

The purpose of this study was to examine the effect of venous occlusion per se on forearm muscle blood flow, as determined by the near-infrared spectroscopy (NIRS) venous occlusion technique (NIRS-VOT). NIRS data were obtained from the flexor digitorum superficialis (FDS) muscle on the dominant arm of 16 young, ostensibly healthy participants (14 men and two women; 30 ± 6 year; 73 ± 7 kg). Participants completed a series of five venous occlusion trials while seated at rest, and a series of 12 venous occlusion trials during a reactive hyperaemia induced by 5 min of forearm arterial occlusion. The NIRS-VOT was used to assess FDS muscle blood flow (Q˙mus), beat-by-beat, over the first four cardiac beats during venous occlusions. Q˙mus was also reported as a cumulative value, wherein the first two, first three and first four cardiac beats were used to calculate muscle blood flow. We observed that Q˙mus was highest when calculated over the first cardiac beat during venous occlusions performed at rest and throughout reactive hyperaemia (P<0·05). Moreover, the inclusion of more than one cardiac beat in the calculation of Q˙mus underestimated muscle blood flows, irrespective of the prevailing level of arterial inflow. These findings support the idea that venous occlusion per se affects the measurement of Q˙mus via the NIRS-VOT. Accordingly, it is recommended that Q˙mus is determined over the first cardiac beat when using the NIRS-VOT to assess microvascular blood flow of human forearm muscles.

Reliability of muscle blood flow and oxygen consumption response from exercise using near‐infrared spectroscopy

“…). As a consequence, inclusion of more than one cardiac beat has been shown to underestimate mBF (Cross & Sabapathy, ; see Fig. B and C ).…”

“…After cuff inflation, there is a rapid, progressive fall in the rate of [tHb] (especially during exercise), probably attributable to an increase in venous back-pressure, diminishing the arteriovenous pressure gradient and stimulating the venoarterial reflex, causing vasoconstriction of precapillary vessels (Rathbun et al 2008). As a consequence, inclusion of more than one cardiac beat has been shown to underestimate mBF (Cross & Sabapathy, 2017;see Fig. 1B and C).…”

“…Estimates of mBF were assessed as the [tHb] signal during VO, analysed using simple linear regression as previously described (Van Beekvelt et al 2001;Cross & Sabapathy, 2017). Briefly, a tourniquet (Hokanson SC 10D; D. E. Hokanson, Inc., Bellevue, WA, USA) was placed as high as possible around the proximal thigh, minimizing patient discomfort and avoiding artefact motion in the NIRS signal.…”

“…Combining NIRS with rapid venous (VO) and arterial (AO) occlusions to estimate mBF and , respectively, has been validated in the forearm (Van Beekvelt et al . ; Cross & Sabapathy, ), calf (Casavola et al . ) and vastus lateralis (VL; Quaresima et al .…”

“…Given that NIRS measures changes in vessels only smaller than 1-2 mm in diameter, it is ideal for assessing local skeletal muscle microcirculation (Mancini et al 1994). Combining NIRS with rapid venous (VO) and arterial (AO) occlusions to estimate mBF and mV O 2 , respectively, has been validated in the forearm (Van Beekvelt et al 2001;Cross & Sabapathy, 2017), calf (Casavola et al 2000) and vastus lateralis (VL; Quaresima et al 2004). However, this technique has been limited to rest and maximal isometric exercise states, and no protocol has been developed to assess reliably both the mBF and mV O 2 responses to specific steady-state exercise.…”