OBJECTIVE: Noninvasive positive pressure ventilation may be considered a first line intervention to treat patients with hypercapnic respiratory failure. However, CO2 rebreathing from the ventilator circuit or mask may impair CO2 elimination and load the ventilatory muscles. This study was conducted to evaluate the effect of exhalation port location and mask design on CO2 rebreathing during noninvasive positive pressure ventilation. DESIGN: Lung model evaluation. SETTING: Experimental laboratory of a large university-affiliated hospital. SUBJECTS: A dual-chamber test lung was used to simulate the ventilatory mechanics of a patient with obstructive lung disease. INTERVENTION: Hypercapnic respiratory failure (end-tidal CO2 of 75 mm Hg) and obstructive lung disease were simulated in a double-chamber lung model. A facial mask (inner volume of 165 mL) with exhalation port within the mask (Facial-MEP) or the same mask with exhalation port in the ventilator circuit (Facial-WS) and a total face mask with exhalation port within the mask (inner volume 875 mL, Total Face) were tested during continuous positive airway pressure and pressure support ventilation provided by a single-limb circuit ventilator at the same frequency and tidal volume. MEASUREMENTS AND MAIN RESULTS: A capnometer and a flow transducer were placed in the lung model upper airway to measure the volume of CO2 rebreathed and tidal volume (Vt). The inspiratory load was estimated from the pressure variation in the lung model driving chamber (PDR). Volume of CO2 rebreathed was smaller during Facial-MEP compared with the other masks in all tested conditions (p <.001). The Vt and PDR necessary to decrease end-tidal CO2 20% (from 75 to 60 mm Hg) was different among the tested masks (Facial-MEP, Vt 701 +/- 9 mL, PDR 8.1 +/- 0.1 cm H2O/sec; Facial-WS, Vt 745 +/- 9 mL, PDR 10.2 +/- 0.1 cm H2O/sec; Total Face, Vt 790 +/- 12 mL, PDR 11.4 +/- 0.2 cm H2O/sec, p <.001). CONCLUSION: Facial-MEP with its exhalation port within the mask and the smallest mask volume demonstrated less rebreathed CO2 and a lower PDR than either the Facial-WS or Total Face masks. Additional studies are necessary to confirm if mask design can clinically affect patient's inspiratory effort during noninvasive positive pressure ventilation.
OBJECTIVE: Noninvasive positive pressure ventilation may be considered a first line intervention to treat patients with hypercapnic respiratory failure. However, CO2 rebreathing from the ventilator circuit or mask may impair CO2 elimination and load the ventilatory muscles. This study was conducted to evaluate the effect of exhalation port location and mask design on CO2 rebreathing during noninvasive positive pressure ventilation. DESIGN: Lung model evaluation. SETTING: Experimental laboratory of a large university-affiliated hospital. SUBJECTS: A dual-chamber test lung was used to simulate the ventilatory mechanics of a patient with obstructive lung disease. INTERVENTION: Hypercapnic respiratory failure (end-tidal CO2 of 75 mm Hg) and obstructive lung disease were simulated in a double-chamber lung model. A facial mask (inner volume of 165 mL) with exhalation port within the mask (Facial-MEP) or the same mask with exhalation port in the ventilator circuit (Facial-WS) and a total face mask with exhalation port within the mask (inner volume 875 mL, Total Face) were tested during continuous positive airway pressure and pressure support ventilation provided by a single-limb circuit ventilator at the same frequency and tidal volume. MEASUREMENTS AND MAIN RESULTS: A capnometer and a flow transducer were placed in the lung model upper airway to measure the volume of CO2 rebreathed and tidal volume (Vt). The inspiratory load was estimated from the pressure variation in the lung model driving chamber (PDR). Volume of CO2 rebreathed was smaller during Facial-MEP compared with the other masks in all tested conditions (p <.001). The Vt and PDR necessary to decrease end-tidal CO2 20% (from 75 to 60 mm Hg) was different among the tested masks (Facial-MEP, Vt 701 +/- 9 mL, PDR 8.1 +/- 0.1 cm H2O/sec; Facial-WS, Vt 745 +/- 9 mL, PDR 10.2 +/- 0.1 cm H2O/sec; Total Face, Vt 790 +/- 12 mL, PDR 11.4 +/- 0.2 cm H2O/sec, p <.001). CONCLUSION: Facial-MEP with its exhalation port within the mask and the smallest mask volume demonstrated less rebreathed CO2 and a lower PDR than either the Facial-WS or Total Face masks. Additional studies are necessary to confirm if mask design can clinically affect patient's inspiratory effort during noninvasive positive pressure ventilation.
Authors: Carolina Fu; Pedro Caruso; Jeanette Janaina Jaber Lucatto; Guilherme Pinto de Paula Schettino; Rogério de Souza; Carlos Roberto Ribeiro Carvalho Journal: Intensive Care Med Date: 2005-10-13 Impact factor: 17.440
Authors: Antoine Cuvelier; Wilfried Pujol; Stéphanie Pramil; Luis Carlos Molano; Catherine Viacroze; Jean-François Muir Journal: Intensive Care Med Date: 2008-10-15 Impact factor: 17.440
Authors: Carmen Sílvia Valente Barbas; Alexandre Marini Isola; Augusto Manoel de Carvalho Farias; Alexandre Biasi Cavalcanti; Ana Maria Casati Gama; Antonio Carlos Magalhães Duarte; Arthur Vianna; Ary Serpa Neto; Bruno de Arruda Bravim; Bruno do Valle Pinheiro; Bruno Franco Mazza; Carlos Roberto Ribeiro de Carvalho; Carlos Toufen Júnior; Cid Marcos Nascimento David; Corine Taniguchi; Débora Dutra da Silveira Mazza; Desanka Dragosavac; Diogo Oliveira Toledo; Eduardo Leite Costa; Eliana Bernardete Caser; Eliezer Silva; Fabio Ferreira Amorim; Felipe Saddy; Filomena Regina Barbosa Gomes Galas; Gisele Sampaio Silva; Gustavo Faissol Janot de Matos; João Claudio Emmerich; Jorge Luis Dos Santos Valiatti; José Mario Meira Teles; Josué Almeida Victorino; Juliana Carvalho Ferreira; Luciana Passuello do Vale Prodomo; Ludhmila Abrahão Hajjar; Luiz Cláudio Martins; Luiz Marcelo Sá Malbouisson; Mara Ambrosina de Oliveira Vargas; Marco Antonio Soares Reis; Marcelo Brito Passos Amato; Marcelo Alcântara Holanda; Marcelo Park; Marcia Jacomelli; Marcos Tavares; Marta Cristina Paulette Damasceno; Murillo Santucci César Assunção; Moyzes Pinto Coelho Duarte Damasceno; Nazah Cherif Mohamad Youssef; Paulo José Zimmermann Teixeira; Pedro Caruso; Péricles Almeida Delfino Duarte; Octavio Messeder; Raquel Caserta Eid; Ricardo Goulart Rodrigues; Rodrigo Francisco de Jesus; Ronaldo Adib Kairalla; Sandra Justino; Sérgio Nogueira Nemer; Simone Barbosa Romero; Verônica Moreira Amado Journal: Rev Bras Ter Intensiva Date: 2014 Apr-Jun
Authors: Onnen Moerer; Peter Herrmann; José Hinz; Paolo Severgnini; Edoardo Calderini; Michael Quintel; Paolo Pelosi Journal: Crit Care Date: 2009-06-05 Impact factor: 9.097