Autonomic function tests consist of a battery of testing involving continuous beat-to-beat blood pressure monitoring and electrocardiographic monitoring during head-up tilt, a series of breathing maneuvers, Valsalva maneuvers, and quantitative sudomotor testing . Valid test results require a relaxed environment where the patient feels at ease, a condition that may be more difficult to achieve if the patient perceives a risk of becoming infected during the visit.
Visits should be scheduled to reduce patient volume in common waiting areas and patients should be advised, where possible, to bring only one additional support person or caregiver (if allowed by institutional policy). Where possible, to limit the face-to-face in office contact time, ancillary information to the testing may be collected with hybrid visits. For example, a brief focused clinical history, questionnaires, and medication reconciliation can be performed in a prior telemedicine virtual visit so that the in-office time is restricted to only autonomic testing procedures. Modifications to patient waiting areas and staff rooms to ensure proper social distancing may be necessary.
Hand sanitizer should be available on check-in. Patients should have undergone the institution-approved clinical COVID screening prior to entering the lab. The number of staff present in the room during autonomic testing should be kept to a minimum.
Patients should wear masks and not remove them while sitting in waiting areas, and when being taken to the examination or testing room. Masks should be worn during all parts of autonomic testing as appropriate and where the mask does not interfere with performance or interpretation of the test. Patients should wear masks during sudomotor testing without affecting the test results. Patients should wear masks during the breathing tests and the head-up tilt table test, if they are tolerated; if there is concern that the masks alter the breathing and secondarily the heart rate and blood pressure responses, it would be appropriate to remove the mask for those tests. During the head-up tilt table test, nausea and dyspnea can occur; if there is concern that masking may worsen nausea or dyspnea or otherwise influence the test results, it would be appropriate to remove the mask during tilt.
A proper Valsalva maneuver test would not be possible with the patient wearing a mask. For the Valsalva maneuver, the mouthpiece must be replaced between patients. A disposable viral filter should be used in between the mouthpiece and the pressure tubing. The increased airflow resistance introduced by an effective filter will not compromise the test result, since increased intrathoracic pressure, not exhaled pressure, is the stimulus for the hemodynamic response. The patient should be instructed to position the mouthpiece themselves and to hold it in place during maneuver, and ideally, staff should maintain a 2-m distance from the patient as they forcefully exhale.
If filters cannot be used, then the tubing will need to be replaced between patients, or cleaned if it is not disposable. If cleaning tubing or other parts, a cleaning solution with antiviral properties should be used that follows vendors’ specifications for cleaning procedures and solutions. Cleaned parts should be dried before reconnection to avoid the risk of damaging the sensor in the data acquisition system. Cleansed parts can be air-dried, if a source of flowing air (not breath-blowing) is available, to help with drying.