Evaluation of negative lowest LAP even after the ASV support
The present study revealed the ability of the ASV treatment to increase the LAP above the atmospheric pressure. On the other hand, the lowest LAP was still negative in seven patients even with ASV support. Previous reports demonstrated that OSA has been associated with an LAP decline during sleep18. Furthermore, obesity, a male gender, hypertension, diabetes mellitus, and heart failure are thought to be important risk factors for OSA19-20. However, those specific patient characteristics could not frequently be observed in patients with a negative LAP after the ASV. In the present study, there were two patients who had been diagnosed with OSA before the ablation procedure, and that might have influenced the results.
We should be aware that a negative LAP after the ASV could be provoked even in patients without OSA, obesity, or other risk factors. Complications due to massive air intrusion could be fatal, and therefore, not only the efficacy but the limitations of ASV on the LAP must be taken into consideration. If further study reveals and predicts the characteristics of the patients with a high risk of an ASV refractory negative LAP, selective and prophylactic bronchial intubation before the procedure could be effective in preventing air intrusion.