Comparison of automatic versus constant CPAP in
elderly patients after major abdominal surgery:
a randomized noninferiority trial

Nguyen Dang Thu; Nguyen Thi Thuy; Le Sau Nguyen; Cong Quyet Thang; Nguyen Ngoc Thach; Nguyen Trung Kien

doi:10.1016/j.bjane.2025.844642

Original Investigation

Comparison of automatic versus constant CPAP in elderly patients after major abdominal surgery: a randomized noninferiority trial

Comparação entre CPAP automático e constante em pacientes idosos após cirurgia abdominal de grande porte: ensaio clínico randomizado de não inferioridade

Nguyen Dang Thu, Nguyen Thi Thuy, Le Sau Nguyen, Cong Quyet Thang, Nguyen Ngoc Thach, Nguyen Trung Kien

http://dx.doi.org/10.1016/j.bjane.2025.844642 Braz J Anesthesiol, vol.75, n5, 844642, 2025

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Abstract

Background

Geriatric patients undergoing major open abdominal surgery are at high risk for postoperative pulmonary complications and hypoxemia. Continuous Positive Airway Pressure (CPAP) after surgery may improve postoperative lung function. This randomized controlled trial compared two CPAP techniques ‒ automatic via nasal mask and constant via facial mask ‒ regarding pulmonary function and patient tolerance.

Methods

Sixty patients (≥ 60 years) were randomized (1:1) to receive either automatic CPAP (2 −10 cm H2O) via a nasal mask (Group A) or constant CPAP (7.5 cm H2O) via a facial mask (Group C) upon arrival in the post-anesthesia care unit. Oxygenation (PaO2, PaO₂/FiO₂, SpO2) and spirometry (FVC, FEV1, PEF) were assessed preoperatively, postoperatively, and one hour after treatment. Comfort scores (0−10, with 0 indicating the best comfort) and complications were recorded.

Results

PaO₂/FiO₂ improvement was lower in Group A (32.6 § 26.3 mmHg) than in Group C (52.9 § 40.1 mmHg; p = 0.023). FVC improvement was also lower in Group A (3.7% § 4.0%) than in Group C (6.7% § 4.9%; p = 0.012). However, Group A had better tolerance, with lower comfort scores (2 [2−3] vs. 3 [2−4], p = 0.002). Pulmonary function benefits were more pronounced in patients over 70 and those undergoing upper abdominal surgery

Conclusion

Both CPAP techniques prevent pulmonary decline in geriatric patients post-surgery. While automatic CPAP provides better comfort, constant CPAP improves oxygenation. Although our findings are short-term, they suggest that CPAP mode selection should be tailored based on patient-specific needs.

Keywords

Continuous positive airway pressure; Elderly; Laparotomy; Patient comfort; Pulmonary function tests

Resumo

Introdução

Pacientes geriátricos submetidos a cirurgia abdominal aberta de grande porte apresentam alto risco de complicações pulmonares pós-operatórias e hipóxia. O uso de Pressão Positiva Contínua nas Vias Aéreas (CPAP) após a cirurgia pode melhorar a função pulmonar no pós-operatório. Este ensaio clínico randomizado controlado comparou duas técnicas de CPAP — automática, por meio de máscara nasal, e constante, por meio de máscara facial — quanto à função pulmonar e à tolerância do paciente.

Métodos

Sessenta pacientes (≥ 60 anos) foram randomizados (1:1) para receber CPAP automático (2–10 cm H₂O) por máscara nasal (Grupo A) ou CPAP constante (7,5 cm H₂O) por máscara facial (Grupo C) ao chegarem à unidade de cuidados pós-anestésicos. A oxigenação (PaO₂, PaO₂/FiO₂, SpO₂) e a espirometria (FVC, FEV₁, PEF) foram avaliadas no pré-operatório, no pós-operatório e uma hora após o tratamento. Os escores de conforto (0–10, sendo 0 o melhor conforto) e as complicações foram registrados.

Resultados

A melhora da relação PaO₂/FiO₂ foi menor no Grupo A (32,6 ± 26,3 mmHg) do que no Grupo C (52,9 ± 40,1 mmHg; p = 0,023). A melhora da FVC também foi menor no Grupo A (3,7% ± 4,0%) do que no Grupo C (6,7% ± 4,9%; p = 0,012). No entanto, o Grupo A apresentou melhor tolerância, com escores de conforto mais baixos (2 [2–3] vs. 3 [2–4], p = 0,002). Os benefícios na função pulmonar foram mais pronunciados em pacientes com mais de 70 anos e naqueles submetidos a cirurgia abdominal superior.

Conclusão

Ambas as técnicas de CPAP previnem o declínio pulmonar em pacientes geriátricos no pós-operatório. Embora o CPAP automático proporcione maior conforto, o CPAP constante melhora a oxigenação. Apesar de nossos achados serem de curto prazo, eles sugerem que a escolha do modo de CPAP deve ser individualizada de acordo com as necessidades específicas de cada paciente.

Palavras-chave

Pressão Positiva Contínua nas Vias Aéreas; Idosos; Laparotomia; Conforto do paciente; Testes de função pulmonar

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Submitted date:
09/01/2025

Accepted date:
03/05/2025