During the entire respiratory cycle in the pleural cavity is retained negative pressure compared with atmospheric nym. The negative pressure is the result of natural hydrochloric lung capacity falls down, and the chest – extension ryatsya. Lung volume at rest, or functional residual capacity (FRC) is a volume in which the outward movement of the chest is equal but opposite to the direction of movement of light inside. In fig. 41 IU is 36% of the lung capacity (VC).
Alveolar pressure is always greater than intrapleural pressure . Therefore, if there is communication between the alveoli and the pleural cavity, air will be directed from the alveoli into the pleural space until a pressure gradient exists or the defect is eliminated.
The effect of pneumothorax on the volume of hemithorax and lung is shown in Fig. 41. This example shows that in plevu tral space has become so much air that the outlet pressure in the pleural cavity increased from -5 to -2,5 cm of water. Art. The volume of the lung on the exhale (point B) decreased from 36 to 11% of the VC, while the volume of gemithorax on the exhale (point B) increased from 36 to 44% of the VC. The total volume of pneumothorax is 33% of vital capacity, of which 25% reflect a decrease Ob EMA lung, and 8% – increase hemithorax .
The main manifestation of pneumothorax is the reduction of VC and Rao2 . Healthy people tolerate well enough
reduction of PE. However, if the lung function was broken on to the occurrence of pneumothorax, the decrease in VC mo Jette lead to respiratory failure with aleeolyarnoy hypoventilation and respiratory acidosis.
The majority of patients with pneumothorax, a decrease Paog and increased alveolar-arterial kitty lorodnoy difference (AAKR). In one of the series of observations in 9 (75%) of the 12 patients with Pao2 was below 80 mm Hg. Art., and 2 – below 55 mm Hg. Art. [11.In the same group at the 10 (83%) of 12 pain GOVERNMENTAL increase AAKR observed. Patients with extensive pneumothorax showed a more significant decrease in Pao2 . In experimental pneumothorax created on conscious dogs which are in the standing position, ny the introduction into the pleural cavity of N2 in an amount of 50 ml / kg, the average Pao2 decreased from 86 to 51 mm . The decrease in PaO2, probably a result of the WHO penetration anatomical shunts and areas with low ventilyatsionno- perfusion indicators in partially atelectised lung. When Norris with colleagues gave their 12 patients with 100% oxygen, the average anatomical shunt them was 10%. A more extensive pnevmotorak se were more prominent shunts. Pneumothorax, for Nima less than 25% of the hemithorax , not associated with increased graft.
In an animal experiment, Moran et al . It showed that the relative perfusion lung pneumothorax not less nyalas, but there was a decrease of ventilation ipsilateral lung, leading to a decrease in ventilyatsionno- perfusion indicators on the side of the pneumothorax. Anthonisen reported that the pneumothorax is observed in the lungs uniform obturation airway at low lung volumes, and likely obstruction of the respiratory tract is the main cause for Rushen ventilation during spontaneous pneumothorax [13J.
As a result of the treatment of pneumothorax Pao2 generally improves camping. In a pilot study Moran and coworkers . [12J averages PaO2 artificial pneumothorax CNI huddled from 86 to 51 mm Hg. Art., but after removing the air, they immediately returned to their original value. Patients normalization Pao2 occurs over a longer ne IRS. After 30-90 min after the removal of air from the pleural hydrochloric cavity in three patients whose primary anatomical shunt exceed 20%, its decrease was observed by more than 10%, but nevertheless, in all patients the shunt was more than 5% . In 3 other patients with anatomical shunts from 10 to 20% were observed changes in the grafts after the removal of a cart of spirit . The timing of the onset of improvement may be related to the duration of pneumothorax.
Pathophysiological features intense pnevmoto Rax will be discussed in subsequent sections of this chapter.
The main symptoms of primary spontaneous pneumothorax are chest pain and shortness of breath. In a group of 39 pain GOVERNMENTAL surveyed Vail and co-workers . , all patients observed were given or chest pain, or shortness of breath. Both symptoms were reported in 25 (64%) patients. Seremetis  notes that chest pains were observed in 140 (90%) of the 155 patients examined by him. Chest pain usual but begin suddenly and are located on the side of pnevmoto Rax. In rare cases, the patient does not feel pain and no shortness of breath. The observations Seremetis 5 (3%) pain GOVERNMENTAL complained only on general malaise. Cases of Horner’s syndrome was reported as a rare complication of spon tannogo pneumothorax and, probably, the emergence of this syndrome is the result of stretching the sympathetic ganglion by changing the position of the mediastinum .
Primary spontaneous pneumothorax usually develops when the patient is at rest. According O’Nara and Seremetis , only 24 (9%) of 258 cases pneumo thorax evolved during significant load. Many pain nye with spontaneous pneumothorax do not seek copper Qing help immediately after the onset of symptoms. ML Noah of a series of observations in 18% of patients with symptoms had been present for a week or more before they applied for copper Qinghelp , in another paper, it was reported that 46% of patients went to a doctor more than 2 days after the onset of symptoms . If the symptoms are observed more than 3 days, do not produce drainage via naso- sa in connection with a high probability of developing lung edema (see. The last section of this chapter).
Physical changes. Characterized by moderate tachycardia. If the pulse rate exceeds 140 beats or hypotension observed or cyanosis, pneumonia should be suspected stressful motoraks (cm. Below section on intense pneumonia motoraksu). Examination of the chest shows that the party lo localization of pneumothorax increased in volume compared with the opposite side and less mobile during respiratory tion Act. Tactile determined voice tremor from absent,percussion giperrezonantna , respiratory sounds on the affected side reduced or nonexistent. Contralateral tracheal dislocation is possible. With right pneumatic motorakse lower edge hepatic dullness can be CME Shchen down.
ECG changes. In patients with spontaneous pnevmotorak catfish can be observed due to their ECG changes. The examination 7 patients with left-sided spontaneous pneumothorax Walston and coworkers .  found a shift of electrical axis of the heart to the right, reducing the voltage tooth tsa R, amplitude reduction QRS and inversion tooth T in the precordial leads. These changes should not be confused with the manifestations of acute subendocardial myocardial myo infarction.
Young people of high growth and asthenic teloslozhe Nia presumptive diagnosis can be made on the OS Considerations history and physical examination of the patient. Confirmed given dia prognosis radiographically . The dubious GOVERNMENTAL cases, the diagnosis can help Roentgen gram in side view in the supine position and, with full exhalation. In 10-20% of patients have concomitant Pleven -sectoral effusion, usually small, radiographically defined trolled in a horizontal liquid level .