Different strategies for lung recruitment in intensive care unit
Alaa Mohammed Ali Etman;
Abstract
The lungs are composed of an external serous coat, a sub serous areolar tissue and the pulmonary substance or parenchyma. The serous coat is the pulmonary pleura; it is thin, transparent, and invests the entire organ as far as the root. The sub serous areolar tissue contains a large proportion of elastic fibers; it invests the entire surface of the lung, and extends inward between the lobules.
The parenchyma is composed of secondary lobules which, although closely connected together by an interlobular areolar tissue, are quite distinct from one another. The secondary lobules vary in size; those on the surface are large, of pyramidal form, the base turned toward the surface; those in the interior smaller, and of various forms. Each secondary lobule is composed of several primary lobules, the anatomical units of the lung.The primary lobule consists of an alveolar duct, the air spaces connected with it and their blood vessels, lymphatic and nerves.
Atelectasis comes from the Greek words atlas and ektasis with the literal meaning “incomplete expansion”. It pertains to collapse, either complete or partial, of the lung, which may subsequently cause decreased volume and diminished gas exchange and can be divided physiologically into obstructive and nonobstructive causes.
Obstructive atelectasis Follows obstruction of a bronchus, the blood circulating in the alveolar-capillary membrane absorbs the gas from alveoli. This process can lead to retraction of the lung and an airless state within those alveoli in a few hours. The loss of contact between the visceral and parietal pleurae is the primary cause of non-obstructive atelectasis. A pleural effusion or pneumothorax causes relaxation or passive atelectasis.
Recruitment maneuver (RM) denotes the dynamic process of an intentional transient increase in transpulmonary pressure (PL) aimed at opening unstable airless alveoli, which has also been termed alveolar recruitment maneuver (AR).
RMs have probably long been used mostly to improve oxygenation, which is a good thing if this improvement results from or is associated with lung recruitment. However, the global effect of RM is actually a balance between positive effects (reduction in VILI, improvement in oxygenation) and negative effects (increase in VILI, hemodynamics impairment). From this balance, one can expect favorable or poor outcome of the patient.
The parenchyma is composed of secondary lobules which, although closely connected together by an interlobular areolar tissue, are quite distinct from one another. The secondary lobules vary in size; those on the surface are large, of pyramidal form, the base turned toward the surface; those in the interior smaller, and of various forms. Each secondary lobule is composed of several primary lobules, the anatomical units of the lung.The primary lobule consists of an alveolar duct, the air spaces connected with it and their blood vessels, lymphatic and nerves.
Atelectasis comes from the Greek words atlas and ektasis with the literal meaning “incomplete expansion”. It pertains to collapse, either complete or partial, of the lung, which may subsequently cause decreased volume and diminished gas exchange and can be divided physiologically into obstructive and nonobstructive causes.
Obstructive atelectasis Follows obstruction of a bronchus, the blood circulating in the alveolar-capillary membrane absorbs the gas from alveoli. This process can lead to retraction of the lung and an airless state within those alveoli in a few hours. The loss of contact between the visceral and parietal pleurae is the primary cause of non-obstructive atelectasis. A pleural effusion or pneumothorax causes relaxation or passive atelectasis.
Recruitment maneuver (RM) denotes the dynamic process of an intentional transient increase in transpulmonary pressure (PL) aimed at opening unstable airless alveoli, which has also been termed alveolar recruitment maneuver (AR).
RMs have probably long been used mostly to improve oxygenation, which is a good thing if this improvement results from or is associated with lung recruitment. However, the global effect of RM is actually a balance between positive effects (reduction in VILI, improvement in oxygenation) and negative effects (increase in VILI, hemodynamics impairment). From this balance, one can expect favorable or poor outcome of the patient.
Other data
| Title | Different strategies for lung recruitment in intensive care unit | Other Titles | الإستراتيجيـات المختلفـة لتطويـع الرئــة فى وحدة العناية المركزة | Authors | Alaa Mohammed Ali Etman | Issue Date | 2016 |
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