The Acute Respiratory Distress Syndrome (ARDS) — acute diffusion inflammatory damage of lungs in response to the pulmonary or extra pulmonary infectious or noninfectious damage leading to increase in permeability of vessels of lungs, increase in mass of lungs, decrease in aeration of pulmonary fabric and the expressed anoxemia.
Mark out the following characteristics of ORDS:
Disturbance of permeability of pulmonary capillaries for water and protein.
Formation of infiltrates in roots of lungs on both sides.
Increase in resistance of pulmonary capillaries.
Decrease in extensibility (komplayens) in lungs.
Decrease in the functional residual lung volume (FOEL).
Staging of a current: an exudation phase (the first several day), a proliferation phase, a fibrosis phase (develops not at all patients).
Now as diagnostic criterion instead of Murray's Scale (1988) use the Berlin criteria of ORDS (2012). The term "Acute Injury of Lungs" (Acute Lung Injury, ALI) is not used any more.
If to tell about treatment acute respiratory a distress syndrome, then in it is possible to talk about the following directions:
Treatment of a basic disease: (antibioticotherapia of sepsis, surgical sanitation of the center of an infection, treatment of shock, etc.).
"Protective ventilation of the lungs" ("pulmonary and protective ventilation"): low respiratory volume of Vt, minimal inspiratory pressure of Pin.
The maneuver "opening of lungs" / "recruitment of alveoluses" / PEEP (diffusion ORDS) is used.
Position of the patient on a stomach was widely used (pron-position).
Control of a water balance, optimization of warm emission.
At inefficiency of treatment inhalation of nitrogen oxide and extracorporal membrane oxygenation (EKMO) can be used.
Respiratory therapy is the cornerstone of treatment of ORDS. IVL has to pursue the aim of protection of lungs (pulmonary and protective ventilation). Its basic principles: to provide a necessary minimum of oxygenation, having as much as possible limited at the same time the damages caused by IVL and to reach optimum compromise between recruitment of the perfused alveoluses and reinflating of the ventilated zones.
The IVL initial parameters at ORDS:
Pressure in respiratory tracts (Pplat) ≤ 30 cm vodn. article;
The respiratory volume (Vt) is about 6 ml/kg of "ideal body weight" (IBW);
IVL purposes at ORDS:
SpO2 = 88–95%, PaO2 = 55–80 mm Hg. at minimum possible FiO2 values;
rn arterial blood = 7.3-7.45.
Before each increase in FiO2, it is necessary to optimize the IVL parameters (to pick up optimum PEEP and a ratio a breath/exhalation of I: E), as high FiO2 (> 60%) is followed by the increased risk of development of atelectases in the patient.
The strategy of "protection of lungs" at ORDS
IVL mode: compulsory ventilation with control on pressure (PCV) with the descending form of a stream curve which means that the inspiratory stream decreases in process of filling of lungs pressure did not grow in respiratory tracts.
Other possible modes:
Two-phase ventilation with positive pressure in respiratory tracts: BIPAP improves ventilation of underlying areas (due to inclusion in work of a diaphragm), without worsening a hemodynamics, and allows to reduce sedation.
Compulsory ventilation with control on volume (at careful control of Pplat).
At the patient with an immunodeficiency in not hard cases noninvasive ventilation is possible (for reduction of risk of the complications caused by a trachea intubation).
Minimum possible pressure in respiratory tracts is used: target indicator of Pin (Pcontrol + PEEP) or Pplat <30 cm vodn. the article (it is better <than 26 cm vodn. article).
Ventilation with a low respiratory volume (Vt = 6 ml/kg of "the ideal body weight").
It is considered that when carrying out MVL at patients with ORDS the risk of a barotrauma increases by 1.3 times by each ml/kg of respiratory volume of Vt> 6 ml/kg. With a growth of Pin> 30 cm vodn. stations against the background of MVL with Vt = 6 ml/kg establish the respiratory volume of Vt at the level of 4 ml/kg of ideal body weight, at the same time development of a hypercapnia is possible.
Restriction of cycles of opening and closing of alveoluses by means of adequate positive pressure at the end of an exhalation (PEEP ≥ 10 cm vodn. article). Widely use so-called recruitment maneuver.
It is important to provide synchronization of the patient with a respirator. Do not recommend to carry out compulsory IVL with use of deep sedation or relaxation without special indications.