Comparación de dos piezas bucales en la medición de PImáx y PEmáx en sujetos adultos / Comparison of two mouthpieces in the measurement of MIP and MEP in adults

Objetivos: Comparar y establecer el grado de acuerdo entre los valores de Presión Inspiratoria máxima (PImáx) y Presión Espiratoria máxima (PEmáx) medidos con pipeta bucal y boquilla de buceo, en adultos. El objetivo secundario fue evaluar el grado de acuerdo entre los valores calculados con las ecuaciones de Evans y Whitelaw y los valores máximos obtenidos con cada interfaz. Materiales y método: Se llevó a cabo un estudio observacional, descriptivo, prospectivo y transversal. Se realizó un muestreo consecutivo no probabilístico de sujetos argentinos entre 18 y 69 años de edad. Se midieron PImáx y PEmáx utilizando un sistema de válvulas unidireccionales y un manovacuómetro aneroide, con boquilla de buceo y pipeta bucal. Resultados: Se incluyeron 240 sujetos que completaron la totalidad de las mediciones con ambas interfaces. Los valores de PEmáx con pipeta bucal fueron mayores que los obtenidos con boquilla de buceo (p < 0.01), con un Coeficiente de Correlación Intraclase (ICC sigla en inglés) entre ambas de 0.80 (IC 95% 0.74-0.84). Para PImáx no hubo diferencias entre ambas interfaces, con un ICC de 0.88 (IC 95% 0.85-0.91). Los ICC para las ecuaciones de Evans y Whitelaw y los máximos valores alcanzados por los sujetos fueron de -0.15 a 0.09 mostraron un grado de acuerdo pobre. Conclusión: Los valores de PEmáx con pipeta bucal fueron mayores que los obtenidos con la boquilla de buceo. No se detectaron diferencias entre ambas interfaces para PImáx. En la población estudiada las fórmulas de Evans y Whitelaw no fueron exitosas en la predicción de presiones máximas.

Objectives: To compare and establish the degree of agreement between the values of Maximal Inspiratory Pressure (MIP) and Maximal Expiratory Pressure (MEP) measured with a plastic mouthpiece and a scuba type mouthpiece in adults. The secondary objective was to evaluate the degree of agreement between the values calculated with Evans and Whitelaw equation and the maximal values attained with each mouthpiece. Methods: We conducted an analytical observational transversal study. Sampling was non-probabilistic, of Argentinian subjects aged between 18 and 69 years old. We measured MIP and MEP with an unidirectional valves system and an aneroid manovacuometer, with a plastic mouthpiece and a scuba type mouthpiece. Results: 240 subjects were included and completed all the measurements with both mouthpieces. MEP values were higher when measured with a plastic mouthpiece than with the scuba type (p < 0.01), with an Intraclass Correlation Coefficient (ICC) between both of 0.80 (CI 95% 0.74-0.84). There were no differences in MIP between both mouthpieces, with an ICC of 0.88 (CI 95% 0.85-0.91). The ICC between Evans and Whitelaw predictive values and the maximal values attained by the subjects varied from -0.15 to 0.09, showing a poor degree of agreement. Conclusion: MEP values attained with a plastic mouthpiece are greater than those attained with a scuba type mouthpiece. There are no differences between both mouthpieces for MIP. Evans and Whitelaw equations are not successful in predicting maximal pressures in the population here studied.

Acute effects of different inspiratory resistive loading on heart rate variability in healthy elderly patients

BACKGROUND: The cardiovascular system is noticeably affected by respiration. However, whether different inspiratory resistive loading intensities can influence autonomic heart rate (HR) modulation remains unclear. OBJECTIVE: The objective was to investigate HR modulation at three different inspiratory resistive loading intensities in healthy elderly men. METHOD: This was a prospective, randomized, double-blind study that evaluated 25 healthy elderly men. Cardiac autonomic modulation was assessed using heart rate variability (HRV) indices. All of the volunteers underwent maximal inspiratory pressure (MIP) measurements according to standardized pulmonary function measurements. Three randomly-applied inspiratory resistive loading (30, 60 and 80% of MIP) intensities were then applied using an inspiratory resistance device (POWERbreathe, Southam, UK), during which the volunteers were asked to inhale for 2 seconds and exhale for 3 seconds and complete 12 breaths per minute. Each effort level was performed for 4 minutes, and HR and the distance between 2 subsequent R waves of electrocardiogram (R-R intervals) were collected at rest and at each intensity for further HRV analysis. RESULTS : The parasympathetic HRV (rMSSD, SD1 and HF) indices demonstrated lower values at 80% (rMSSD: 19±2 ms, SD1: 13±2 ms and HF: 228±61 ms2) than at 30% MIP (rMSSD: 25±3 ms, SD1: 18±2 ms and HF: 447±95 ms2; p<0.05). CONCLUSIONS: Lower inspiratory resistive loading intensities promoted a marked and positive improvement of parasympathetic sinus node modulation. .

The Relationships of Coughing to the Respiratory Muscle Strength and Pulmonary Compliance in Tetraplegic Patients

OBJECTIVE: To analyze the factors influencing the capacity of cough, the relationships between maximal respiratory pressure, lung compliance, capacity of cough, and assisted cough techniques were evaluated in tetraplegics. METHOD: The vital capacity (VC) in seated and supine position, maximum insufflation capacity (MIC), maximum inspiratory (MIP) and expiratory (MEP) pressure in seated position were measured. Unassisted and assisted peak cough flow (PCF) at two different conditions (a volume assisted method by the mechanical insufflation [PCFmic] and the manual assistance by abdominal compression [MPCF]) were evaluated in 44 tetraplegic patients. RESULTS: The mean value of VC in supine was greater than that of seated position (p<0.01). The MICs of the subjects were significantly higher than VCs in a same position (<0.01). Both volume and manual assisted method showed significantly higher PCF than unassisted PCF (p<0.01). MIP (r=0.53) correlated with UPCF as well as MEP (r=0.68), although MEP was better correlated with UPCF. CONCLUSION: Generally the therapists apply manual pressure only to increase capacity of cough, which assist the expulsive phase. The results of this study showed that both inspiratory and expulsive phases should be assisted to enhance the effectiveness of cough.