The effects of external diaphragmatic pacing on diaphragm function and weaning outcomes of critically ill patients with mechanical ventilation: a prospective randomized study

BACKGROUND: Diaphragmatic pacing can improve diaphragm function, which is beneficial for the prognosis of patients treated with prolonged mechanical ventilation (MV). While most previous studies have focused on the role of implanted diaphragm pacing (IDP), our study is the first to examine the effects of external diaphragmatic pacing (EDP) in mechanically ventilated patients. Specifically, the effect of EDP on diaphragm function, the success rate of weaning, the duration of MV (DMV), and the intensive care unit (ICU) length of stay (ILOS) were assessed. METHODS: From September 2019 to December 2020, a total of 51 mechanically ventilated patients in the ICU of the Sun Yat-sen Memorial Hospital, Sun Yat-sen University were enrolled and randomly divided into an EDP group of 27 patients and a control group of 24 patients. The control group received routine treatment, and the EDP group received EDP treatment in addition to routine treatment. The diaphragm excursion (DE), diaphragm thickening fraction (DTF), DMV, ILOS, and average survival time were recorded to evaluate efficacy. RESULTS: Patients treated with EDP had increased DE [exp(B) =1.86, 95% CI: 1.39 to 2.50, P<0.001] and DTF [exp(B) =1.35, 95% CI: 1.05 to 1.76, P=0.022], shortened weaning time (P=0.026) and prolonged average survival time (P<0.001) compared to patients who did not receive EDP therapy. Especially in cases with difficult weaning, the improvement of DE and DTF in the EDP treatment group was more obvious than that in the control group (P=0.013 and P=0.032). Moreover, the DTF upon attempted spontaneous breathing trial (SBT) was negatively correlated with the fraction of inspired oxygen (FiO(2)) [r=−0.54; 95% confidence interval (CI): −0.77 to −0.19; P=0.004], the arterial partial pressure of oxygen (PaO(2)) (r=−0.58; 95% CI: −0.79 to −0.25; P=0.001), the PaO(2)/FiO(2) ratio (r=−0.52; 95% CI: −0.75 to −0.16; P=0.006), and the serum lactate concentration (Lac) (r=−0.39; 95% CI: −0.68 to 0.003; P=0.046). CONCLUSIONS: EDP treatment can effectively reduce the DMV and prolong the average survival time of mechanically ventilated patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1900024096.