Showing posts from April, 2023

Can't Catch Your Breath? Calcium Channel Blockers and Pulmonary Shunting - A Deep Dive

  Periodically, a patient on the unit on a nicardipine or clevidipine infusion develops what appears to be unexplainable hypoxia. The situations are inevitably multifactorial, but often end with a workup for pneumonia, PE, or volume overload turning up dry and a question to me about whether it could have been the nicardipine all along. Despite the frequency in which continuous infusion CCBs are used in the NeuroICU this doesn't come all that often, so my answer often boils down to "well, theoretically" - vasodilators, including CCBs and nitroprusside 1 (see also here 2 ), have been demonstrated to be capable of reversing hypoxia-induced pulmonary vasoconstriction, so it is perfectly within the realm of possibility that nicardipine could contribute to pulmonary shunting and thus new-onset hypoxia. The adverse effects are only briefly mentioned in the package inserts of either nicardipine or clevidipine, with major Phase III trials not reporting it at all. Because of t