Tuesday, April 2, 2013

Emergency Therapy For Acute Respiratory Failure

Respiratory Failure (RF)
   Is  the pathological  state, at which breathing organs are unable to provide adequate saturation of organism by oxygen and destroy  carbon dioxide.

 Anatomic and physiological   features of respiratory organs
1.  High metabolism, greater necessities in oxygen, however less compensating possibilities of organs of breathing;
2. Uncomplete differentiation of tissues;
3. Narrow respiratory tracts;
4. Undevelopment of additional cavities of nose, absence of lower nasal passage;
5. Propensity to the edema of mucous - through large amount of   vessels (ventilation failure);
6. The features of larynx structure (tender of cartilaginous ring, narrow upper space, expressed submucous tissue) ® croup.

•Tender trachea, bronchial tubes, little amount of   elastic tissues ® narrowing of respiratory road ® swollen mucus, hypersecretion of bronchial glands ® obstructions (hypoventilation -emphysema);
Undevelopment of cilia epithelium ® propensity to violation of evacuation function of respiratory tract;
•Lungs sanguineous, small elastic and many connective tissue  ® restrictive RF (exudation, аtelectasis, emphysema);
•Horizontal placing of ribs, low retractive ability of diaphragm ® diminish of   the excursion of lungs.

                                    Etiology of RF
                      The reasons leading to the development of acute respiratory failure are a lot. The most frequent causes of respiratory failure are listed below.
                                     1. Obstructive type
a) Obstruction of the upper respiratory tract may occur when there are abnormalities of development (atresia choanae, Pierre Robin syndrome, stenosis of the larynx above the vocal cords), aspiration of gastric contents, or foreign body, infections (epiglottitis), allergic laryngism, the tissue changes (tumor, cyst, hypertrophy of tonsils).
b) Obstruction of the lower airways may occur when there are abnormalities of development (bronhomalacia, lobar Emphysema), aspiration (in the presence of traheoezophageal fistula, infections (mumps, bronchiolitis, pneumonia), inflammation, bronchospasm (asthma, bronchopulmonary dysplasia), as well as foreign bodies.
                        2. Restrictive violations

a) With the defeat of the parenchyma of the lungs. Hypoplasia of lung, RDS, pneumothorax, hemorrhage, pulmonary edema and pleurisy.
b) With the defeat of the chest wall. Diaphragmatic hernia, absence of ribs, hypoplasia and aplasia of the sternum, chest deformity (rickets), abdominal distension, kyphoscoliosis, trauma restricted mobility of the chest, severe myasthenia pseudoparalitic, muscular dystrophy, and obesity.
                                 3. Diseases that lead to inadequate gas alveoli and
                                                        capillaries exchanges

a) Diseases of the violations of diffusion. Diffuse type of RF: lung edema, interstitial fibrosis, collagenosis, pneumonia (Pneumocystis carinii), desquamative interstitial pneumonia.
b) Diseases due to inhibition of the respiratory center (Ventilation type of RF). Traumatic brain injury, CNS infection, overdose of sedatives; severe asphyxia and tetanus.
                      4. Other situations that contribute to the development of the
                          acute respiratory distress
a) An increase in hydrostatic pressure.
b) Congestive heart failure.
c) The excess of fluid injected.
d) Intestinal obstruction.
e) Chronic broncho-pulmonary diseases

Etiologic classification of respiratory insufficiency

1. RF related to the obstruction of respiratory tracts (larynx-, bronchiolo-, bronchospasm, foreing body);
2. RF as a result of violation of diffusion of gases through an alveolar-capillary membrane (pneumonias, chronic diseases of lungs);
3. RF related to the damage of respiratory system (trauma of thorax, pneumo- thorax);
4. RF of central genesis - arises up at the damage of cerebrum (edema of brain, meningitis, cranial-cerebral trauma);
5. RF conditioned by violation of neuro-muscular conductivity (poliomyelitis, myasthenia)

                                   Clinic of respiratory insufficiency

1. Disturbances of function of the external breathing: shortness of breath, difficulty of breathing, prolonged exhalation, participation of auxiliary muscles, nod motions by a head, blowing of nostrils, violation of rhythm of breathing (bradypnoe, pathological type of breathing);
      2. Signs of hypercapnia, hypoxia: tachycardia, decreased arterial pressure, pallor of skin, acrocyanosis, cyanosys, excitation or oppression of child;
     3. Signs of tissue hypoxia: pallor -gray color of skin, bradycardia, decreased arterial pressure and comma.
                      Clinical manifestations are divided into 3 groups.
                       1. Pulmonary symptoms
a) In infants and children with acute respiratory failure - tachypnea, violations of the depth and rhythm of respiratory movements, retraction of the intercostal spaces, the expansion of nostrils, cyanosis, sweating.
b) possible shortness of breath and wheezing.
                      2. Neurological symptoms.
As a result of increased sensitivity of the brain to hypoxemia there is developing headache, anxiety, irritability, convulsions, and sometimes coma.
                     3. Symptoms of the cardiovascular system.
 There are bradycardia and hypotension. Severe and /or prolonged
 respiratory failure can lead to heart  failure and pulmonary edema.
Clinical classification of respiratory insufficiency

  I   stage: the shortness of breath in rest is absent, perioral cyanosys, which increases at loading, PS: BR – 3,5-2,5: 1; РаО2 – 80-65 mm Hg
The ІІ stage: is   the shortness of breath in rests, perioral cyanosys, acrocyanosis permanent, participation of auxiliary musculature in the act of breathing, PS: BR – 2-1,5: 1
 РаО2 – 64-51mmHg
The ІІІ stage: is the expressed shortness of breath in rest, the unrhythmical breathing (paradoxical breathing), generalized cyanosys is permanent, does not disappear at breathing by oxygen;
 РаО2 – 50 and ¯

                   Respiratory failure in acute pneumonia is 3 degrees.
      At I degree respiratory insufficiency is compensated by hyperventilation, there are no breathing disorders. At II degree there are the clinical and laboratory signs of disorders of external respiration, hemodynamics, but they are subcompensated. At III degree decompensation is diagnosed, both external and internal respiration.

Spirography determines the speed and volume of breath

Clinical features of RDS in newborn

1.Tachypnoe (BR > 60),  bradypnoe (BR <35);
2. Cyanosys;
3. Retractions (drawing in of pliable places of chest);
4. Blowing of wings of nose;
5. Grants (expiration moan);
6. Disturbance of rhythm or breathing;
7. Reduced activity.

                           Treatment of respiratory failure

           The treatment depends on the leading pathological process, as well as the degree of hypoxemia, pCO2 and pH. For the recovery there is necessary to liquidate respiratory failure (removal of foreign body, the causes of the collapse of the lung: pneumothorax, lobar emphysema, diaphragmatic hernia).

             1. Oxygenation should begin only after the removal of the contents of the airways and should be performed using mixtures containing a minimum amount of oxygen that allows to maintain an adequate level of arterial pO2 (> 60 mmHg). The use of excessive concentrations of O2, may provoke pulmonary edema, atelectasis, or lead to retinopathy in preterm infants. If resistant to treatment forms of hypoxemia are present it needs intubation for ensuring long-term positive pressure in the lungs.
               2. Liquidation of  the disorders in the lungs involves the removal of bronchial secretion, the appointment of bronchodilators, intubation, or connecting to a respiration apparatus.
                      a) Endotracheal or nasotraheal intubation is enough to eliminate
                       obstruction of the upper respiratory tract.
                       The correct location of the tube should be monitored auscultation
                       or X-ray.
                      b) Increasing the humidity of air reduces the viscosity of bronchial
               3. Intubation and ventilation with positive pressure is needed in patients
                          with elevated values of pCO2, accompanied by respiratory acidosis.


A - Basic:
1.      Pediatrics. Textbook. / O. V. Tiazhka, T. V. Pochinok, A. N. Antoshkina et al. / edited by O. TiazhkaVinnytsia : Nova Knyha Publishers, 2011 – 584 pp. : il.
2.      ISBN 978-966-382-355-3Nelson Textbook of Pediatrics, 19th Edition Kliegman, Behrman. Published by Jenson & Stanton, 2011, 2608.  ISBN: 978-080-892-420-3.
3.      Illustrated Textbook of Paediatrics, 4th Edition.  Published by  Lissauer & Clayden, 2012, 552 p. ISBN: 978-072-343-566-2.
4.      Denial Bernstein. Pediatrics for medical Students. – Second edition, 2012. – 650 p.
B - Additional: 1.http://intranet.tdmu.edu.ua/data/kafedra/internal/pediatria2/classes_stud/шпитальна%20педіатрія/6%20курс/English/Theme%2001%20Differential%20diagnosis%20of%20pneumonia%20in%20children.htm
2. http://www.merckmanuals.com/professional/index.html
3. Lichtenstein, et al. Pediatric Pneumonia. Emergency medicine clinics of north America.  2010.
4. Barson.  Clinical manifestations and diagnosis of community-aquired pneumonia in children. UpToDate.com., 2009.

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