Year Book: One Hundred Percent Incidence of Hemidiaphragmatic Paresis

---

Associated With Interscalene Brachial Plexus Anesthesia as Diagnosed by Ultrasonography. Urmey-WF. Talts-KH. Sharrock-NE. 1992 Year Book of Orthopedics. Article 2-42. Original Article: Anesth Analg. 1991. 72. pp 498-503. Background.--Sensory anesthesia of the fourth and fifth cervical nerves is a routine part of interscalene brachial plexus anesthesia for shoulder surgery. Interscalene blocks that produce surgical C3-C5 sensory anesthesia should cause some degree of diaphragmatic paralysis. The incidence of ipsilateral hemidiaphragmatic paresis during routine interscalene block was assessed by ultrasonography. Methods.--Thirteen healthy patients who were scheduled for elective upper extremity surgery with interscalene blocks were evaluated. Brachial plexus block was achieved with an injection of 34-52 mL of 1.5% mepivacaine with 5 microgram/mL of epinephrine and .05 mEq/mL of sodium bicarbonate. All of the patients had cervical sensory anesthesia. Ultrasonography measurements were made 2, 5, and 10 minutes after injection and hourly after surgery in 11 patients. Conclusions.--Interscalene brachial plexus block anesthesia for shoul der surgery appears to result inevitably in diaphragmatic paresis. Although this may occur without symptoms, more marked changes in ventilation may occur in patients with preexisting respiratory system pathology.