High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease

Background: The physiological effects of high-flow nasal cannula O2therapy (HFNC) have been evaluated mainly in patients with hypoxemic respiratory failure. In this study, we compared the effects of HFNC and conventional low-flow O2therapy on the neuroventilatory drive and work of breathing postextubation in patients with a background of chronic obstructive pulmonary disease (COPD) who had received mechanical ventilation for hypercapnic respiratory failure. Methods: This was a single center, unblinded, cross-over study on 14 postextubation COPD patients who were recovering from an episode of acute hypercapnic respiratory failure of various etiologies. After extubation, each patient received two 1-h periods of HFNC (HFNC1 and HFNC2) alternated with 1 h of conventional low-flow O2therapy via a face mask. The inspiratory fraction of oxygen was titrated to achieve an arterial O2saturation target of 88-92%. Gas exchange, breathing pattern, neuroventilatory drive (electrical diaphragmatic activity (EAdi)) and work of breathing (inspiratory trans-diaphragmatic pressure-time product per minute (PTPDI/min)) were recorded. Results: EAdi peak increased from a mean (±SD) of 15.4 ± 6.4 to 23.6 ± 10.5 μV switching from HFNC1 to conventional O2, and then returned to 15.2 ± 6.4 μV during HFNC2 (conventional O2: p<0.05 versus HFNC1 and HFNC2). Similarly, the PTPDI/minincreased from 135 ± 60 to 211 ± 70 cmH2O/s/min, and then decreased again during HFNC2 to 132 ± 56 (conventional O2: p<0.05 versus HFNC1 and HFNC2). Conclusions: In patients with COPD, the application of HFNC postextubation significantly decreased the neuroventilatory drive and work of breathing compared with conventional O2therapy

High-flow oxygen therapy in tracheostomized patients at high risk of weaning failure

Purpose: High-flow oxygen therapy delivered through nasal cannulae improves oxygenation and decreases work of breathing in critically ill patients. Little is known of the physiological effects of high-flow oxygen therapy applied to the tracheostomy cannula (T-HF). In this study, we compared the effects of T-HF or conventional low-flow oxygen therapy (conventional O2) on neuro-ventilatory drive, work of breathing, respiratory rate (RR) and gas exchange, in a mixed population of tracheostomized patients at high risk of weaning failure. Methods: This was a single-center, unblinded, cross-over study on fourteen patients. After disconnection from the ventilator, each patient received two 1-h periods of T-HF (T-HF1 and T-HF2) alternated with 1 h of conventional O2. The inspiratory oxygen fraction was titrated to achieve an arterial O2 saturation target of 94–98% (88–92% in COPD patients). We recorded neuro-ventilatory drive (electrical diaphragmatic activity, EAdi), work of breathing (inspiratory muscular pressure–time product per breath and per minute, PTPmusc/b and PTPmusc/min, respectively) respiratory rate and arterial blood gases. Results: The EAdipeak remained unchanged (mean ± SD) in the T-HF1, conventional O2 and T-HF2 study periods (8.8 ± 4.3 μV vs 8.9 ± 4.8 μV vs 9.0 ± 4.1 μV, respectively, p = 0.99). Similarly, PTPmusc/b and PTPmusc/min, RR and gas exchange remained unchanged. Conclusions: In tracheostomized patients at high risk of weaning failure from mechanical ventilation, T-HF did not improve neuro-ventilatory drive, work of breathing, respiratory rate and gas exchange compared with conventional O2 after disconnection from the ventilator. The present findings might suggest that physiological effects of high-flow therapy through tracheostomy substantially differ from nasal high flow

Additional file 3: of High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease

Independent sample t tests. Comparison between patients admitted for hypercapnic respiratory failure due to an exacerbation of COPD and patients with a background of COPD but whose hypercapnic respiratory failure was due to other precipitating causes in terms of EAdi parameters or work of breathing during each experimental condition. (DOCX 60 kb

Polymyxin-B hemoperfusion in septic patients: analysis of a multicenter registry

Background: In 2010, the EUPHAS 2 collaborative group created a registry with the purpose of recording data from critically ill patients suffering from severe sepsis and septic shock treated with polymyxin-B hemoperfusion (PMX-HP) for endotoxin removal. The aim of the registry was to verify the application of PMX-HP in the daily clinical practice. Methods: The EUPHAS 2 registry involved 57 centers between January 2010 and December 2014, collecting retrospective data of 357 patients (297 in Europe and 60 in Asia) suffering from severe sepsis and septic shock caused by proved or suspected infection related to Gram negative bacteria. All patients received atleast one cycle of extracorporeal endotoxin removal by PMX-HP. Results: Septic shock was diagnosed in 305 (85.4 %) patients. The most common source of infection was abdominal (44.0 %) followed by pulmonary (17.6 %). Gram negative bacteria represented 60.6 % of the pathogens responsible of infection. After 72 h from the first cycle of PMX-HP, some of the SOFA score components significantly improved with respect to baseline: cardiovascular (2.16 \ub1 1.77 from 3.32 \ub1 1.29, p < 0.0001), respiratory (1.95 \ub1 0.95 from 2.40 \ub1 1.06, p < 0.001) and renal (1.84 \ub1 1.77 from 2.23 \ub1 1.62, p = 0.013). Overall 28-day survival rate was 54.5 % (60.4 % in abdominal and 47.5 % in pulmonary infection). Patients with abdominal infection treated with PMX-HP within 24 h from the diagnosis of septic shock had a 28-day survival rate of 64.5 %. Patients showing a significantly cardiovascular improvement after PMX-HP had a 28-survival rate of 75 % in comparison to the 39 % of patients who did not (p < 0.001). Cox regression analysis found the variation of cardiovascular, respiratory and coagulation SOFA to be independent covariates for 28-day survival. In European patients were observed a higher 28-day (58.8 vs. 34.5 %, p = 0.003), ICU (59 vs. 36.7 %, p = 0.006) and hospital survival rate (53.2 vs. 35 %, p = 0.02) than in Asian patients. However, the two populations were highly heterogeneous in terms of source of infection and severity scores at admission. Conclusion: The EUPHAS 2 is the largest registry conducted outside Japan on the clinical use of PMX-HP in septic patients. Data analysis confirmed the feasibility of PMX-HP to treat septic patients in daily clinical practice, showing clinical benefits associated with endotoxin removal without significant adverse events related to the extracorporeal technique