Pursed lips breathing improves ventilation in myotonic muscular dystrophy.

OBJECTIVE: To determine the effects of pursed lips breathing on ventilation, chest wall mechanics, and abdominal muscle recruitment in myotonic muscular dystrophy (MMD). DESIGN: Before-after trial. SETTING: University hospital pulmonary function laboratory. PARTICIPANTS: Eleven subjects with MMD and 13 normal controls. INTERVENTION: Pursed lips breathing. OUTCOME MEASURES: Electromyographic (EMG) activity of the transversus abdominis, external oblique, internal oblique, and rectus abdominis was recorded with simultaneous measures of gastric pressure, abdominal plethysmography, and oxygen saturation. Self-reported sensations of dyspnea, respiratory effort, and fatigue were recorded at the end of each trial. RESULTS: Pursed lips breathing and deep breathing led to increased tidal volume, increased minute ventilation, increased oxygen saturation, reduced respiratory rate, and reduced endexpiratory lung volume. Dyspnea, respiratory effort, and fatigue increased slightly with pursed lips breathing. EMG activity of the transversus abdominis and internal oblique muscles increased in MMD only and was associated with an increase in gastric pressure. CONCLUSIONS: Pursed lips breathing and deep breathing are effective and easily employed strategies that significantly improve tidal volume and oxygen saturation in subjects with MMD. Abdominal muscle recruitment does not explain the ventilatory improvements, but reduced end-expiratory lung volume may increase the elastic recoil of the chest wall. Further clinical studies are needed to ascertain if the ventilatory improvements with pursed lips breathing and deep breathing improve pulmonary outcomes in MMD.

Relationship between subjective fatigue and physiological variables in patients with chronic obstructive pulmonary disease.

Patients with chronic illnesses, such as chronic obstructive pulmonary disease (COPD), report an increase in the perception of fatigue in the clinical setting. Subjective fatigue associated with physiological factors has not been reported. The purpose of this study was to determine the relationship between subjective fatigue and pulmonary function, respiratory and peripheral muscle force and exercise capacity in patients with COPD. Nineteen patients with COPD participated in the study [mean (SD) FEV1 38% (17%) predicted]. Fatigue was measured with the Multidimensional Fatigue Inventory 20 (MFI-20) that includes the following subscale dimensions: general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue. The following physical variables were measured: forced expiratory volume in 1 s (FEV1), vital capacity (VC), maximal inspiratory peak pressure (PImax), symptom-limited bicycle exercise capacity (maximum workload) and maximal voluntary isometric muscle force of both left and right quadriceps (Qu), hamstrings (Ha), biceps (Bi) and triceps (Tr). The MFI-20 fatigue dimensions, reduced activity and reduced Motivation, are significantly correlated with FEV1 (% predicted) (r = -0.62, r = -0.55 respectively). No significant correlation was found between the dimensions of fatigue and maximum workload. In contrast the fatigue dimension, physical fatigue, shows significant correlations with seven of eight muscle forces measured (Qu left r = -0.49, right r = -0.54; Ha left r = -0.49, right r-0.38; Tr left r = -0.61, right r = -0.45; Bi left r = -0.46, right r = -0.48). Data from this study show that activity and physical dimensions of subjective fatigue are related to pulmonary function and skeletal muscle force in COPD patients. Interventions to improve skeletal muscle force might improve subjective fatigue in patients with COPD.

Respiratory muscle function in patients with chronic obstructive pulmonary disease.

Respiratory muscle (RM) dysfunction is a progressive process, including both RM weakness and fatigue, that may advance to the point of respiratory failure. It occurs as a result of increased RM workloads, altered length-tension relationship of respiratory muscles, malnourished states, and altered cellular environment in chronic obstructive pulmonary disease (COPD). Consideration of multiple patient factors is necessary when identifying patient risk for RM dysfunction and designing plans of care. This article discusses the RM pump, including its measurement, in patients with COPD.

Functional status instruments: outcome measure in the evaluation of patients with chronic obstructive pulmonary disease.

The purpose of this article is to review the instruments developed to measure functional status in patients with chronic obstructive pulmonary disease. Because the ability to carry out day-to-day activities is of primary importance to patients with chronic obstructive pulmonary disease, it is necessary for clinicians to understand which instruments provide the best measures of patient activity levels. Furthermore, as a critical outcome in managed care services, pulmonary critical pathways, and patient disability, the measurement of functional status in clinical practice assumes greater relevance. Functional status instruments in this review will refer to questionnaires measuring the day-to-day activities of patients. Questionnaires reviewed will include those that provide measures of general health status with activity-specific items, as well as questionnaires specifically designed to evaluate patients with pulmonary disease. The psychometric strengths, reliability and validity, and clinical utility of the instruments will be presented.

Respiratory responses to unsupported arm lifts paced during expiration.

Unsupported arm exercise endurance is reduced in both normal subjects and patients with chronic obstructive pulmonary disease in association with an increase in dyspnea and alterations in the pattern of respiratory muscle recruitment. Some report greater difficulty carrying out arm activity paced during the expiratory phase of respiration rather than during inspiration. The purpose of this study was to determine the effect of unsupported arm exercise lifts paced in phase with expiration (EUAL) on (a) diaphragm recruitment measured as the electromyographic amplitude (EMG-DI), (b) the pattern of thoracoabdominal motion measured with inductive plethysmography, and (c) the sensation of dyspnea measured with a 100 mm visual analog scale. Data were collected from 18 normal adult subjects at baseline and during EUAL. When compared with rest, EUAL resulted in significant increases in mean inspiratory and expiratory diaphragm EMG amplitudes, dyssynchronous thoracoabdominal motion, and dyspnea intensity. These changes in diaphragm recruitment and thoracoabdominal motion may in part explain reports of increased dyspnea intensity with unsupported arm exercise.

Instrument development in the measurement of unsupported arm exercise endurance in normal adult subjects.

Many daily activities, from basic grooming to employment tasks, require adequate unsupported arm endurance (UAE). We developed an electromechanical device to measure UAE endurance. The purpose of this study was to standardize the instrument for two rates of arm motion, moderate and slow, in 18 normal adult subjects (FEVI = 3.7L +/- .78, FVC = 4.2L +/- .74, FEV1/FVC = 1.1 +/- .08). Exercise endurance limits, and the following metabolic, ventilatory, and sensation responses were determined at rest prior to exercise and at end-exercise limits for both rates of UAE:minute ventilation (Ve), tidal volume (VT), respiratory rate (RR), duty cycle (Ti/Ttot), oxygen uptake (VO2), carbon dioxide production (VCO2), inspiratory flow (VT/Ti), heart rate (HR), and visual analog scale measurements (VAS) of dyspnea (D), respiratory effort (RE), and arm fatigue (AF). Significance increases from baseline rest were shown at the endurance limits for both rates of UAE in: VO2, VCO2, Ve, VT, RR, VT/Ti, HR, VAS-D, VAS-RE, and VAS-AF. There were no changes in Ti/Ttot and SaO2 with UAE. Peak VO2, RR, Ve, VT/Ti, and VAS-D with moderate exercise were significantly greater than slow UAE; and there was a trend increase in peak HR for moderate as opposed to slow rate UAE. Despite these differences, the endurance time between the two rates of UAE were similar. These data provide standards against which UAE in COPD can be evaluated.

Standardization of a device to measure unsupported arm exercise endurance in chronic obstructive pulmonary disease.

The purpose of this study was to compare respiratory responses with moderate and slow rates of unsupported arm exercise (UAE) with a newly developed electromechanical device. Twenty-one patients with chronic obstructive pulmonary disease (COPD) were studied. Exercise endurance limits, metabolic, ventilatory and sensation outcomes were determined at rest prior to exercise and at end-exercise endurance limits. Increases from baseline rest for both exercise rates were observed in: oxygen uptake, carbon dioxide production, inspiratory flow, minute ventilation, respiratory rate, dyspnea, respiratory effort, and arm fatigue. Endurance limits were similar for both rates of UAE. These data provide standards against which UAE in COPD can be evaluated.

Dyspnea-limited response in chronic obstructive pulmonary disease: reduced unsupported arm activities.

Dyspnea, the sensation of uncomfortable breathing, is the primary activity-limiting symptom leading to reduced functional ability in chronic obstructive pulmonary disease (COPD). Patients with severe COPD report a marked increase in the sensation of dyspnea with routine tasks that require arm use, especially activities necessitating unsupported arm elevation. Dyspnea is associated with alterations in respiratory muscle function, such as an increase in muscle force requirement, a reduction in respiratory muscle strength and endurance, and an increase in the recruitment of the rib cage and accessory muscles. Unsupported arm exercise (UAE) further compromises respiratory muscle capacity for ventilation because it requires the muscles' concomitant recruitment in the maintenance of chest wall stabilization. This article presents respiratory muscle mechanisms leading to reduced UAE, methods of measuring unsupported arm endurance, and treatment strategies to improve unsupported arm activity endurance in patients with COPD.

The pattern of respiratory muscle recruitment during pursed-lip breathing.

Data from the present study indicate a change in the pattern of chest wall muscle recruitment and improved ventilation with pursed-lip breathing (PLB) in COPD. Pursed lip breathing led to increased rib cage and accessory muscle recruitment during inspiration and expiration, increased abdominal muscle recruitment during expiration, decreased duty cycle of the inspiratory muscles and respiratory rate, and improved SaO2. In addition, PLB resulted in no change in pressure across the diaphragm and a less fatiguing breathing pattern of the diaphragm. Changes in chest wall muscle recruitment and respiratory temporal parameters concomitant with the increased SaO2 indicate a mechanism of improving ventilation with PLB while protecting the diaphragm from fatigue in COPD. Alterations in the pattern of respiratory muscle recruitment with PLB may be associated also with the amelioration of dyspnea. Further investigation is necessary to explore the relationship between the pattern of respiratory muscle recruitment during PLB and dyspnea.

Physiological nursing research in dyspnea: a paradigm shift and a metaparadigm exemplar.

Dyspnea, the primary activity-limiting symptom in chronic obstructive pulmonary disease, is associated with respiratory muscle mechanisms. This leads to a paradigm shift from pulmonary processes to respiratory muscle function. Within the context of an integrative metaparadigm, basic and clinical nursing science are developed: to better understand physiological processes associated with dyspnea as presented in three physiological models of dyspnea, to identify respiratory muscle mechanisms associated with current treatment strategies for dyspnea, to eventuate clinical assessments of exercise endurance, and to generate treatment strategies in the promotion of positive life processes. The basic knowledge developed within this program provides a foundation for the generation of strategies to assess patients, to promote normal functioning of life processes, and to enhance positive coping with responses to illness. Thus, this research program provides a model for the development of substantive physiological and clinical knowledge for nursing practice.

Correlations between dyspnea, diaphragm and sternomastoid recruitment during inspiratory resistance breathing in normal subjects.

The purpose of this study was to determine the relationship between recruitment of the DI and SM muscles measured as EMG signal amplitudes, the pattern of respiratory muscle recruitment measured with inductive plethysmography, and the intensity of the sensation of dyspnea, measured with 100 mm VAS. Eighteen normal subjects between the ages of 33 and 47 breathed under two conditions: normal controlled breathing and breathing against an inspiratory resistance at 60 percent of their maximal inspiratory pressure (MIP). The PM, RR, duty cycle (TI/TTOT, and VT were held constant. During resistance breathing, VAS dyspnea was increased when EMG-DI decreased; EMG-SM increased in association with the sensation of dyspnea. During inspiratory resistance breathing, dyspnea markedly increased and rib cage and accessory muscle recruitment was the predominant pattern of breathing. These data suggest that dyspnea may be associated with the recruitment of the accessory respiratory muscles rather than the recruitment of the diaphragm.

Prevention and treatment of pulmonary complications in patients after surgery of the upper abdomen.

Pulmonary complications are the leading cause of morbidity and death during the postoperative period in patients who have undergone upper abdominal surgery. Significant pulmonary mechanical alterations, such as reductions in VC, TV, and FRC and an increase in CV, are noted postoperatively in this patient population. Preexisting patient conditions, postoperative treatments, and certain respiratory maneuvers may increase the patient's risk in the development of postoperative pulmonary complications. Current research unanimously advocates sustained maximal inspiration, the normal physiologic sigh maneuver, as the best method of prevention and treatment of this problem. Commonly utilized maneuvers, such as blowing into a rubber glove or bag, blow bottles, and the like, should be avoided in all situations. A guide for preoperative and postoperative pulmonary assessment and care based on current research is included. After consideration of the data in addition to personal clinical experience, I conclude that to prevent pulmonary complications in patients after upper abdominal surgery, as well as in all hospitalized patients, sustained maximal inspiration, preferably with an incentive spirometer, and conscientious nurse supervision and coaching is the method of choice.