Diaphragmatic Dysfunction After Supraclavicular Brachial Plexus Block

This study will be an observational trial to assess the onset time and incidence of hemidiaphragmatic paresis in patients who undergo the double injection ultrasound-guided supraclavicular block. Diaphragmatic dysfunction will be determined by intercostal diaphragm thickening measured using ultrasound. The available image will be saved.

Patients having below the elbow surgery will be be approached by someone from the research team for consent and possible inclusion in the study. This will be done in the anesthesia preoperative assessment clinic, or in the pre-op area on the day of surgery (if a patient was not seen in clinic).

A baseline ultrasonographic diaphragmatic assessment will be completed. Study participants will then receive supraclavicular brachial plexus block as per standard of care. Ultrasonographic diaphragmatic assessment and dyspnea score (using modified Borg dyspnea scale) will be performed every 5 minutes for 30 minutes, or until the patient is transferred to the operating room, whatever comes first. Patients will also undergo an ultrasonographic diaphragmatic assessment and dyspnea score in the recovery room after their surgery.

Inclusion criteria

• Patients presenting for unilateral upper extremity surgery below the level of the elbow (the forearm or hand) who are having a double injection regional block for anesthesia
• 18 years old and over
• Weight 50kg or greater
• English speaking
• American Society of Anesthesiologists physical status 1-3

Exclusion criteria

• Known Chronic Obstructive Pulmonary Disease
• Pregnancy
• Any significant neurologic dysfunction, or inability to visualize the diaphragm during baseline sonographic assessment