[en] Background. Peak cough flow (PCF) it's the parameter that most correlates with the ability to cough and the effectiveness of it to eliminate airway secretions in patients with respiratory muscle weakness. The literature describes mainly two instruments, which are the pneumotachometer and the peak expiratory flow meter (PEF), combined with two interfaces, a mouthpiece and a mask. Objetive. The objective of this study is to compare both instruments and interfaces in the measurement of PFT to determine if there are statistically significant differences, in addition to analyzing which are the sociodemographic, anthropometric, spirometric and physical activity variables that have the greatest influence on PFT. Methods. Cross-sectional study on 31 healthy adults in which PFT is measured using two measuring instruments (pneumotachometer and PEF meter) combined with two different interfaces (mouthpiece and mask). Outcomes The values of the PFT with pneumotachometer (PFTpn) were 510.42±114.89 L/min with mask (PFTpnm) and 488.23 ± 104.47 L/min with mouthpiece (PFTpnb). The PFT values with PEF meter (PFTm) were 544.03 ± 116.04 L/min with mask (PFTmm) and 56613±132.00 L/min with mouthpiece (PFTmb). The differences were statistically significant in the comparison of measuring instrument and in the comparison of interfaces only when they are connected to a pneumotachograph. Conclusions There are statistically significant differences in the comparison of the instruments, favorable to the PEF meter. In the comparison of interfaces, statistically significant differences only occur when they are connected to the pneumotachograph, registering higher values with the mouthpiece. The variables in our study that had a relationship with the PFT have been weight, height, FVC, VEMS and PEF.

[gl] Introdución. O pico fluxo de tose (PFT) é o parámetro que máis se correlaciona coa capacidade tusigena e a eficacia da mesma para eliminar as secrecions da vía aérea en pacientes con debilidade dos músculos respiratorios. A literatura describe para a súa medición principalmente dous instrumentos, o pneumotacógrafo e o medidor do pico fluxo espiratorio (PEF), combinadas con dúas interfaces, unha boquilla e unha máscara. Obxectivo. O obxectivo deste estudo é comparar tanto os instrumentos como as interfaces na medición do PFT para determinar se existen diferenzas estatisticamente significativas, ademais de analizar cales son as variables sociodemográficas, antropométricas, espirométricas e de actividade física que maior influencia teñen sobre o PFT. Material e método Estudo descritivo observacional de corte transversal sobre 31 adultos sans nos que se mide o PFT empregando dous instrumentos de medida (pneumotacógrafo e medidor do PEF) combinados con dúas interfaces diferentes (boquilla e máscara). Resultados. Os valores do PFT con pneumotacógrafo ( PFTpn) foron 510,42±114,89 L/min con máscara ( PFTpnm) e 488,23±104,47 L/min con boquilla ( PFTpnb). Os valores do PFT con medidor do PEF (PFTm) foron 544,03±116,04 L/min con máscara (PFTmm) e 566,13±132,00 L/min con boquilla (PFTmb). As diferenzas foron estadísticamernte significativas na comparación do instrumento de medición e na comparación da interface cando se conectou a un pneumotacógrafo. Conclusións Existen diferenzas estatisticamente significativas na comparación dos instrumentos, a favor do medidor do PEF. Na comparación das interfaces, as diferenzas estatisticamente significativas só se dan entre a boquilla e a máscara, cando se conectan cun pneumotacógrafo, rexistrando maiores valores a favor da boquilla. As variables recollidas no noso estudo que gardaron unha relación co PFT foron o peso, a talla, o CVF, o VEMS e o PEF.