Effect of thermal helium oxygen mixture оn сentral hemodynamics and oxygen transport in patients with acute hypercapnic respiratory failure with chronic obstructive pulmonary disease

The aim of this study is to assessment of the rapid effects of t-He/O2 in comparison with the effective level of high-flow oxygen therapy (HPO) on the main indicators of oxygen transport, central and pulmonary hemodynamics in patients with chronic obstructive pulmonary disease (COPD) with hypercapnic acute respiratory failure.Methods. A total of 33 (29 male, 4 female) patients were included in a randomized, comparative study with exacerbation of COPD and acute respiratory failure, admitted to the department of anesthesiology and intensive care of D.D.Pletnev City Teaching Hospital, Moscow Healthcare Department, between March and May 2017. Patients were divided into two groups: the 1st group – 18 patients (15 male, 3 female) receiving t-He/O2 (He – 70%, O2 – 30% at a temperature of 70 °C; the 2nd group – 15 patients (14 male, 1 female) receiving high-flow oxygen therapy with FiO2 – 30% through a Venturi mask for the treatment of ODN against the background of basic therapy of the underlying disease, according to the recommendations of GOLD 2016. Assessment of oxygen transport, central and pulmonary hemodynamics was carried out through the definition of indicators: saturation of hemoglobin of arterial blood with oxygen (SaO2), saturation of venous blood hemoglobin with oxygen (SvO2), partial pressure of arterial blood oxygen (РaO2), partial pressure of arterial blood carbon dioxide (РaCO2), partial pressure of mixed venous blood oxygen (РvO2), partial pressure of mixed venous blood carbon dioxide (РvCO2),mean pulmonary artery pressure (MPAP), cardiac output (SV), heart index (CI), pulmonary vascular resistance (RVRI), impact volume index (SVI), pulmonary vascular resistance index (RVRI), left ventricular shock index (LVSW), right ventricular shock index (RVSW), system speed of oxygen delivery (DO2), the coeffiCIent of extraction of oxygen (ExO2), shunt fractions (venous mixing) (Qs / Qt)).Results. Short-term inhalation with a thermal helium-oxygen mixture in patients with COPD with hypercapnic acute respiratory failure is accompanied by an increase in SaO2 94,1 (92,8; 97,5) initially 86,1 (85,9; 88,1), РаО2 (78,1 (74,8; 80,1) initially 55,2 (52,5; 65,3)), decline РаСО2 (57,4 (54,2; 66.4) initially 65,4 (58,1; 67,2)). Thermal helium-oxygen mixture leads to stabilization of hemodynamics, improving the work of the right and left heart: decline MPAP 28,2 (24,3; 32,8) initially 43,3 (40,1; 49,5), RVRI (285,3 (258,4; 362,7) initially 592,1 (498,2; 623,5)), RVSW (16,2 (14,1; 21,4) initially 25,8 (21,8; 32)), HR 91,1 (86,4; 98,7) initially 115 ((105; 118) to increase LVSW (58,2 (49,8; 62,4) initially 35,5 (28,9; 42,1)), SVI 36,2 (31,8; 42,1) initially 31,5 (28,4; 36,2). Elimination of arterial hypoxemia and a positive effect on hemodynamics ensures adequate oxygen transport to tissues, which is expressed in the normalization of DO2 values DO2 (980,4 (858,45; 1208) initially 280,3 (270,34; 387,4)) и ExO2 (27,8 (25,6; 34,5) initially 32,1 (30,7; 39,8) and decline Qs/Qt. (28,7 (18,6; 35,4) initially 42,8 (39,2; 49,1).Conclusion. Short-term therapy of patients with COPD with hypercapnic acute respiratory failure using the t-He/O2 method, in comparison with high-flow oxygen therapy, improves blood oxygenation and hemodynamics. Elimination of arterial hypoxemia and a positive effect on hemodynamics made it possible to ensure adequate oxygen transport to tissues, which was expressed in the normalization of transport values, oxygen delivery, and a decrease in the shunt fraction.

How should we monitor patients with acute respiratory failure treated with noninvasive ventilation?

Noninvasive ventilation (NIV) is currently one of the most commonly used support methods in hypoxaemic and hypercapnic acute respiratory failure (ARF). With advancing technology and increasing experience, not only are indications for NIV getting broader, but more severe patients are treated with NIV. Depending on disease type and clinical status, NIV can be applied both in the general ward and in high-dependency/intensive care unit settings with different environmental opportunities. However, it is important to remember that patients with ARF are always very fragile with possible high mortality risk. The delay in recognition of unresponsiveness to NIV, progression of respiratory failure or new-onset complications may result in devastating and fatal outcomes. Therefore, it is crucial to understand that timely action taken according to monitoring variables is one of the key elements for NIV success. The purpose of this review is to outline basic and advanced monitoring techniques for NIV during an ARF episode.