Kazuyuki Tabira

Effect of modulated-frequency and modulated-intensity transcutaneous electrical nerve stimulation after abdominal surgery: a randomized controlled trial.

Purpose:This study aimed to evaluate the effectiveness of transcutaneous electrical nerve stimulation (TENS) for treatment of postoperative pain and pulmonary functions (vital capacity [VC]; cough peak flow, [CPF]) in patients who underwent abdominal surgery. Materials and Methods:Forty-eight patients were randomly allocated to receive TENS, placebo TENS, or no TENS (control) 1 hour a day for 3 days postoperatively. A 0-100 visual analog scale was used to assess pain at preintervention, mid-intervention, and postintervention on the third postoperative day. Pulmonary functions (VC, CPF) were evaluated by spirometer at preoperation (baseline) and at preintervention, mid-intervention, and postintervention on the third postoperative day. One-way analysis of variance was used to assess differences between groups at baseline. Mann-Whitney test was used to compare the control group with the placebo-TENS and TENS group, at each assessment timepoint. Two-way analysis of variance and Bonferroni post hoc test assessed the difference between the 2 (placebo-TENS×TENS) groups. A value of P<0.01 was considered statistically significant. Results:The baselines were not significantly different between any groups. The TENS group had significant reductions in postoperative pain compared with the placebo group (P<0.01) and control group (P<0.01). There was also improvement in pulmonary functions (VC, CPF) at mid-TENS and post-TENS, but not in the placebo-TENS (P<0.01) or control groups (P<0.01). Conclusions:TENS is a valuable treatment to alleviate postoperative pain and improve pulmonary functions (ie, VC, CPF) in patients following abdominal surgery.

The relationship between skeletal muscle oxygenation and systemic oxygen uptake during exercise in subjects with COPD: a preliminary study.

BACKGROUND: Muscle oxygenation correlates with systemic oxygen uptake (V̇O2) in normal subjects; however, whether this relationship exists in COPD patients remains unclear. The purpose of this study was to investigate the influence of skeletal muscle oxygenation on V̇O2 during exercise in patients with COPD. METHODS: Eight subjects performed an incremental cycle ergometer exercise test. We measured ventilation and pulmonary gas exchange with a metabolic measurement system. We also continuously monitored SpO2, and measured tissue oxygen saturation (StO2) in the vastus lateralis with continuous-wave near-infrared spectroscopy. We calculated the muscle oxygen extraction rate (MOER) based on SpO2 and StO2. In addition, we calculated Pearson correlation coefficients to examine the relationships between the V̇O2 obtained during exercise testing and the mean values of SpO2, StO2, heart rate (HR), and MOER for each 30-second interval of the tests. Finally, we analyzed the relationships between the peak V̇O2 and the slopes of HR/V̇O2, SpO2/V̇O2, StO2/V̇O2, and MOER/V̇O2. RESULTS: With the increasing exercise intensity, many subjects showed a gradual decrease in StO2 and SpO2, but a gradual increase in HR and MOER. V̇O2 was negatively correlated with StO2 and SpO2, and was positively correlated with HR and MOER. However, peak V̇O2 was not correlated with any of the slopes. CONCLUSIONS: V̇O2 is highly influenced by oxygen utilization in exercising muscles, as well as by blood oxygenation levels and cardiac function. However, the impact of skeletal muscle utilization during exercise on peak V̇O2 varied greatly among the subjects.

Influence of mild hypoxia on cardiorespiratory responses and muscle oxygenation during incremental exercise

pressure of arterial oxygen and has an influence on ventilatory, circulatory and metabolic processes during exercise; measuring the gas exchange has been used to study cardiorespiratory response under hypoxic conditions. Recently, muscle metabolism and oxygenation, as well as arterial oxygenation and cardiorespiratory action, are seen as being limited in healthy subjects under hypoxic conditions, and also under conditions of pulmonary patient induced hypoxemia. To assess muscle metabolism, muscle biopsy during resting and phosphorus magnetic resonance spectroscopy during exercise are often used and to assess muscle Introduction oxygenation; using arterial and venous blood sampling. However, this requires invasive techniques, which limits its application to physiological and clinical measurements. Recently, measurements using near infrared spectroscopy (NIRS) have made it possible to noninvasively measure in vivo changes in tissue of both oxygenated and deoxygenated hemoglobin and myoglobin. Although several incremental exercise experiments in hypoxic conditions have been reported5-7, 9, 10, 13, 15-17) , few investigations have been done in respect to the relationship between cardiorespiratory responses and oxygenation in exercising muscle during mild hypoxia. The purpose of this study was to determine the relationships among gas exchange responses, blood lactate concentrations, and NIRS responses during Influence of mild hypoxia on cardiorespiratory responses and muscle oxygenation during incremental exercise