A Study On The Effects Of Different Loads Of Inspiratory Muscle Training On Cardiopulmonary Function In Patients With Chronic Heart Failure

Objective:This study aimed to investigate the effect of different load intensity training on cardiopulmonary function in patients with chronic heart failure(CHF)through rehabilitation treatment with different load inspiratory muscle training.The changes in inspiratory muscle function,cardiac circulation function,pulmonary function,and exercise tolerance were observed before and after treatment to investigate the effect of inspiratory muscle training in delaying the occurrence of impaired cardiopulmonary function in patients with chronic heart failure.This study used two different load inspiratory muscle training programs to improve cardiopulmonary function.By evaluating the effectiveness of exercise intervention on preventing inspiratory muscle weakness in patients with heart failure,and provide a theoretical and practical basis for the subsequent study of the inspiratory muscle training program in patients with chronic heart failure.Methods:This study used a randomized controlled trial method.39 patients with chronic heart failure who met the inclusion criteria were enrolled from October 2019 to December 2020 and included in the study.The patients were divided into non-training control group and 30%PImax medium-intensity group(n=3)and 60%PImax high intensity group(n=2).There was no statistical difference in the general data and baseline data among the three groups.Finally,33 patients completed the trial,and 6dropped out(3 in the control group,1 in the medium intensity group,and 2 in the high-intensity group).The control group only received conventional drug treatment and general nursing;the moderate-intensity group was given intervention with a total time of 1 hour,including three stages:warming up,breathing training,and collating exercise in addition to conventional drug treatment and general nursing.The specific training time is(1)Warm-up:a series of cycle training instruments are used to perform flexion and extension,adduction and abduction of the shoulder,elbow,and hip and knee joints for 10 min;(2)Respiratory training:conventional respiratory training and inspiratory muscle training for 40 min(including the rest time during training),of which conventional respiratory training includes abdominal breathing method,flute breathing method,diaphragmatic resistance training,thoracic relaxation method for 20 min;Power Breathe?K5(UK)training system is used for inspiratory muscle training with30%PImax intensity for 20 min;(3)collation training is performed with resonance therapy instrument for 10 min;the high-intensity group has the same intervention as the medium-intensity group except that the inspiratory muscle training intensity is 60%PImax.The training frequency was 5 days per week,once a day for 1 hour.The intervention lasted for a total of 6 weeks.Meassurement:Inspiratory muscle function parameters(maximum inspiratory pressure(MIP),muscle strength index(S-index),and peak inspiratory flow rate(PIF))were collected at enrollment and after 6 weeks of intervention using the Power Breathe?K5(UK)test system;cardiopulmonary exercise testing and training system produced by Schiller,Switzerland,was used in combination with a power bicycle for cardiac circulatory function(resting heart rate(HRrest),peak heart rate(HRpeak),peak oxygen pulse(VO₂rest/HR),systolic blood pressure(SBP),diastolic blood pressure(DBP)),pulmonary function(vital capacity(VC),carbon dioxide ventilation equivalent slope(VE/VCO₂slop),maximum ventilation(MVV),forced vital capacity(FVC),forced expiratory volume in 1 second(FEV1),rate in 1second(FEV1/FVC)),exercise tolerance(exercise time,peak oxygen uptake(VO₂peak),peak kilogram oxygen uptake(VO₂peak/kg),anaerobic threshold oxygen consumption(VE/VCO₂slop),and METs)were collected.Statistical analysis:T-test,ANOVA,Rank-sum test and Chi-square analysis were used to analyze the effect before and after the intervention,ANOVA was used to analyze the differences between groups.Tukey's method was used for post-test if the differences between groups were significant,and P<0.05 was considered statistically significant.Results:1.There were significant differences in the improvement of MIP,S-index,and PIF in patients with chronic heart failure after 6 weeks of high-intensity inspiratory muscle training compared with those before training,but there was no difference in the control group before and after intervention.2.There were significant differences in the improvement of SBP after 6 weeks of high-intensity inspiratory muscle training compared with that before training in patients with chronic heart failure.There were significant differences in the improvement of VO₂peak/HR after high-intensity inspiratory muscle training.There was no significant difference in the control group before and after intervention.3.There were significant differences in the improvement of VC,VE/VCO₂slop,MVV,FVC,FEV1,and FEV1/FVC between the high-intensity group and the control group after 6 weeks of high-intensity inspiratory muscle training,but there was no significant difference in the improvement of VC and FEV1 between the high-intensity group and the control group before and after intervention.4.There were significant differences in the improvement of exercise time,VO₂peak/kg,VO₂AT,and METs between the high-intensity and control groups after 6 weeks of high-intensity inspiratory muscle training in patients with chronic conditions heart failure.There were significant differences in the improvement of VO₂peak after high-intensity training.There were significant differences in the improvement of exercise time and METs between the high-intensity group and the control group.There were significant differences in the improvement of METs between the high-intensity and medium intensity groups.The control group did not differ before and after the intervention.Conclusion:For patients with chronic stable heart failure,the application of inspiratory muscle training is safe and effective,whether 30%PImax medium intensity or 60%PImax high-intensity inspiratory muscle training will improve the cardiopulmonary function of patients after 6 weeks,including MIP,S-index,PIF,SBP,VC,VE/VCO₂slop,MVV,FVC,FEV1,FEV1/FVC.The improvement of VC,FEV1,METs and exercise time in high intensity group was better than that in control group after training.Compare with medium-intensity group,improvement of VO₂peak/HR,VO₂peak and METs was better in the high-intensity group.The effects of HRrest,HRpeak and DBP on chronic heart failure were not significant.Medium intensity inspiratory muscle training had no significant effect on VO₂peak/HR and VO₂peak in patients with chronic heart failure.