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Updated: Jun 26, 2026
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Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention
Published on: October 16, 2013
Hypotension and pulmonary atelectasis during general anaesthesia: a randomised crossover laboratory study
Erland Östberg1, Cecilia Wassberg2, Mark Lubberink3
1Department of Anaesthesia and Intensive Care, Västmanland Hospital Västerås, Sweden; Centre for Clinical Research Västmanland, Department of Surgical Sciences, Uppsala University, Sweden.
British Journal of Anaesthesia
|June 24, 2026
Summary
Hypotension during general anesthesia increases lung atelectasis. This study in pigs shows that low blood pressure causes more atelectasis and alters blood flow distribution, suggesting a new risk factor.
Area of Science:
- Anesthesiology and critical care medicine
- Pulmonary physiology
- Medical imaging
Background:
- Atelectasis is a common complication during general anesthesia, leading to postoperative pulmonary issues.
- Existing preventive strategies are insufficient, indicating other contributing factors may exist.
- This study investigates the role of hypotension in anesthesia-induced atelectasis.
Purpose of the Study:
- To test the hypothesis that hypotension contributes to atelectasis formation during general anesthesia.
- To quantify the effect of induced hypotension on atelectasis volume.
- To assess changes in pulmonary blood flow distribution and oxygen saturation under hypotensive conditions.
Main Methods:
- A randomized, evaluator-blinded crossover study was performed on 12 anesthetized, mechanically ventilated pigs.
- Profound hypotension was induced using nitroprusside and compared to normotension during simulated anesthesia induction.
- Total atelectasis volume was measured by computed tomography; pulmonary blood flow distribution was assessed using [15O]-water positron emission tomography.
Main Results:
- Atelectasis volume was significantly greater during induced hypotension (median MAP 46 mmHg) compared to normotension (median MAP 85 mmHg) in 11 of 12 pigs (P<0.001).
- Hypotension caused a redistribution of pulmonary blood flow towards dorsal lung regions (182% vs. 129% of total flow).
- Mixed venous oxygen saturation decreased during hypotension (43% vs. 48% with normotension).
Conclusions:
- Profound hypotension significantly increased atelectasis in an experimental anesthesia induction model.
- Findings suggest hypotension contributes to atelectasis via pulmonary blood flow redistribution and reduced oxygen saturation in dorsal lung regions.
- Hypotension during general anesthesia induction may be an unrecognized risk factor for pulmonary atelectasis.
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