Atelectasis during anaesthesia and in the postoperative period

Area of Science:

• Anesthesiology
• Pulmonary Medicine
• Radiology

Background:

• Anesthesia and surgery can lead to changes in lung tissue.
• Dependent lung densities are observed during anesthesia.

Purpose of the Study:

• To investigate the development and persistence of lung densities during and after anesthesia.
• To compare lung changes between different anesthesia types and ventilation methods.

Main Methods:

• Computerized tomography (CT) scans of lung tissue were obtained during anesthesia and postoperatively.
• Patients received either intravenous (thiopentone) or inhalational (halothane) anesthesia.
• Lung densities were assessed during spontaneous and mechanical ventilation, and at 1 and 24 hours postoperatively.

Main Results:

• All patients developed dependent, crest-shaped lung densities within 5-10 minutes of anesthesia.
• These densities occupied 3.4% of the lung volume in the basal region.
• No significant differences were found between anesthesia types or ventilation methods.
• Densities persisted in 90% of patients at 1 hour and 50% at 24 hours postoperatively.

Conclusions:

• Anesthesia rapidly induces compression atelectasis, likely due to diaphragmatic relaxation.
• These lung densities are a common finding during and after anesthesia.
• Persistent atelectasis may contribute to postoperative pulmonary complications.