Pneumothorax in mechanically ventilated patients: diagnosis and aggressive treatment

2021-08-01 11:38 PM

Pneumothorax is a very dangerous, potentially fatal, complication in patients on artificial ventilation

Pneumothorax is a potentially fatal complication associated with mechanical ventilation. Most patients with ventilator-associated pneumothorax have underlying lung disease; Pneumothorax is rare in intubated patients with normal lungs. Tension pneumothorax is more common in mechanically ventilated patients and prompt recognition and treatment is critical to minimizing morbidity and mortality. The underlying lung disease is associated with ventilator-associated pneumothorax with pneumothorax occurring most commonly during the early stages of mechanical ventilation. The diagnosis of pneumothorax in critical illness is established from the patient history, physical examination, and radiographs, although the appearance of a pneumothorax on supine radiographs may differ from its appearance on radiographs. routine optics. For this reason,

Pneumothorax is a very dangerous complication in patients with artificial ventilation.

Patients most at risk for this complication are:

Patients with obstructive airway disease: severe asthma attack, chronic obstructive pulmonary disease.

Patients with ARDS, acute lung injury (ALI).

Cases that are not the above diseases but the ventilator parameters are set improperly, causing excessive tidal volume increase also have the risk of developing pneumothorax.

Definite diagnosis

Clinical symptoms

The patient's dyspnea increased rapidly.

Peak airway pressure increases, anti-machine.

Unilateral chest tightness, poor mobility, reduced or absent alveolar murmur, internal percussion.

Accompanying subcutaneous emphysema may be detected.

Cyanosis, increased blood pressure (severe respiratory failure) or low (critical respiratory failure), tachycardia.

Subclinical symptoms

Hypoxemia: SpO 2 drops, blood gas test has decreased PaO 2 , SaO 2 decreased.

Chest X-ray allows the diagnosis of pneumothorax, requiring bedside imaging. However, many cases are too urgent to wait for an X-ray diagnosis.

Differential diagnosis

Differential diagnosis from other causes of rapidly worsening respiratory failure in mechanically ventilated patients such as airway obstruction, ventilator failure. III.

Treatment

Pleural drainage

When clinical signs suggest pneumothorax, thoracentesis should be performed immediately if the patient has severe respiratory distress. At that time, pleural puncture also has diagnostic value because it is impossible to wait for a chest X-ray to make a diagnosis.

Minimal pleural opacification is required quickly, placing a tube with a large enough aperture (24-32F) into the pleural space for continuous air suction.

Negative pressure is usually adjusted between -15 and -30cm of water. When the suction pressure is strong enough and the tube aperture is large enough, the pneumothorax will disappear gradually. Conversely, if the pneumothorax does not decrease, or even increases and subcutaneous emphysema occurs, a stronger suction pressure should be adjusted or a larger aperture tube should be considered.

When the pleura is empty, the lungs are well dilated, turn off the suction machine and monitor if the air continues to come out.

Remove the drain if after 12-24 hours there is absolutely no sign of air in the pleura (air does not come out through the drain, X-ray shows that there is no air in the pleura).

Reset machine parameters

Decreased tidal volume (Vt), decreased PEEP level.

Increase FiO 2 to keep SpO 2 satisfactory (try to keep SpO 2 from 92% or more).

The patient should be allowed to breathe in a controlled manner, not using support/control. Give the patient sedation so that the patient can breathe on the machine. Use muscle relaxants if sedation is not enough to help the patient breathe completely on the machine.

Adjust Vt to keep plateau pressure < 35cm water.

Monitoring and prevent disease

Monitoring

Monitoring the pleural drainage tube:

Make sure the tube is well ventilated, monitor the status of air and fluid out through the drain. If the tube is clogged, it should be replaced immediately.

Monitor for infection at the drainage site.

Monitoring progress of pneumothorax:

If the condition does not improve, the ventilator setting and drain status should be reviewed. Increase suction pressure or replace drain if necessary.

Monitoring for respiratory failure:

Pneumothorax will complicate the patient's respiratory failure and increase the risk of death.

Preventive

Use alveolar hypoventilation (Vt < 8 ml/kg or less) when mechanically ventilated high-risk patients.

Keep plateau pressure < 35cm water during mechanical ventilation. Many studies have found plateau pressure > 35cm water to be a predictor of the occurrence of pneumothorax in mechanically ventilated patients. Therefore, plateau pressure must be measured periodically in all mechanically ventilated patients, especially in patients at risk of pneumothorax.