Mechanical ventilation of the lungs is one of the most widespread methods of treatment of patients in intensive care units and resuscitation. This method is capable to provide to the patient as replacement of function of external respiration at its full stop, and support of spontaneous ventilation of the patient if this function at it is kept.
During the development artificial ventilation of the lungs underwent a set of changes and took place a way from simple volume support of breath to the difficult highly intellectual modes which are capable to define independently extent of necessary respiratory support and to provide it to the patient.
In process of development of mechanical ventilation of the lungs also the relation of specialists to this method changed. If in the beginning idea of artificial ventilation was based that it certainly is useful, then further, in process of accumulation of clinical experience, there were more and more data on negative impact of IVL on function of lungs and also about the various complications accompanying this type of treatment. For this reason now idea of so-called protective artificial ventilation of the lungs, that is the technique providing protection of the patient in the course of carrying out to it respiratory therapy was created.
Speaking actually about a patronage, it should be noted that it is first of all about protection of healthy or rather healthy part of lungs, that is that their part which or is not involved in pathological process, or is involved in it in insignificant degree. This protection means protection of healthy or rather healthy part of lungs from the damaging action of the most mechanical ventilation. Purpose of protective IVL: minimization of risk of small ventilating damages. At the correct carrying out protective IVL increases survival of the patients who are on mechanical ventilation.
If to speak about a pathophysiology of the small damages caused by ventilation, then it is about a mechanical trauma, a biotrauma and shunting of a blood-groove owing to it. It is well-known that mechanical ventilation by receipt from the outside of respiratory mix in lungs of the patient is not physiologic as at the same time pressure increases in respiratory tracts and conditions for development of a barotrauma and a volyumotravma are created. Patholologically the changed part of lungs usually has lower extensibility that leads to restretching of healthier sites in the course of carrying out ventilation. Also in the course of carrying out IVL conditions for forming of atelectases are quite often created. All this leads to a so-called biotrauma. The mechanical injury of lungs together with a biotrauma and shunting of a blood-groove leads to increase of an anoxemia that in turn leads to increase of a syndrome of multiorgan insufficiency.
There are several ways of reduction of risk of the caused ventilyation of small damages. First, this restriction of respiratory volume to necessary figures and also restriction of pressure on a breath up to the safe sizes. Secondly, this use of positive pressure at the end of an exhalation (PEEP) and also if necessary recruitment maneuver. Thirdly, this ensuring ventilation and perfusion of various sites of lungs, that is use of a pron-position.
The basic principles of protective IVL consist in the following. Use restriction of respiratory volume to 5–7 ml/kg of ideal body weight. Use restriction of pressure on a breath: Pplat less than 30 cm w.g., ∆P (Pplat — PEEP) less than 15 cm w.g. Besides, use prevention of an atelektotravma — positive pressure at the end of an exhalation (PEEP). Besides, sufficient time of a breath and exhalation, sufficient oxygenation and a permissive hypercapnia matter (only if there are no contraindications). Avoid a hyperoxia — oxygen concentration on a breath has to make no more than 60% whenever possible. It is known that excessively high concentration of oxygen on a breath renders negative effect.
The concept of ultraprotective IVL was developed for treatment acute respiratory a distress syndrome: respiratory volume is 3-3.5 ml/kg, qualitative sedation of the patient, extracorporal removal of carbon dioxide, regulation of PEEP and FiO2 for achievement of necessary oxygenation and also EKMO at an anoxemia, refractory to other methods.
Now are developed and various modes continue to be developed for protective ventilation of the lungs. Besides, high-quality monitoring of breath, a hemodynamics and other parameters of the patient for timely reaction and fast assessment of the situation is of great importance.