A 53-year-old lady from Kathmandu presented with complaints of pain and swelling over the left arm following fall on the ground. She also complained of on and off productive mucoid cough since last six months. There is no history of chronic obstructive pulmonary disease, pulmonary tuberculosis, hypertension, diabetes mellitus, or any other illness. She also had swelling over the left chest which was diagnosed based on tissue biopsy as small round-cell tumor of the chest wall. She had also undergone chemotherapy with dexamethasone one month prior to injury. She had a history of on and off backache in the thoracolumbar area, nonradiating, intermittent, relieved by analgesics, and aggravated by mild exercise but with no history of trauma. She was also a known case of somatoform disorder under clonazepam.
On examination, her vitals were stable, and other systemic examination was within normal limit. Airway examination showed short neck and Mallampati of grade III. Local examination revealed swelling and tenderness over the left midarm. Her initial laboratory investigations showed increased total count with neutrophilic predominance and thrombophilia. Serum calcium was normal, but serum phosphorous was low (1.5 mg/dl). Her serum creatinine was raised to 7.5 mg/dl with blood urea of 106 mg/dl. Urinary Bence Jones protein was positive. Immunochemistry revealed high beta 2 microglobulin (13616 ng/ml), high alpha 1 and 2 globulin (0.56 g/dl and 1.08 g/dl, respectively), and low serum albumin (3.09 gm/dl). Noncontrast computed tomography showed multiple lytic lesions in the body of thoracic vertebra with a collapse of D8 vertebra. She was hence diagnosed as multiple myeloma, admitted to the hospital, and optimized. On preanesthesia evaluation, the total count was high (16,400/mm3); hemoglobin, 8.3 gm%; thrombophilia, 5,98,000/mm3; and prothrombin time 12.4 seconds with international normalized ratio of 1.00. Her acute kidney injury (blood urea 50 mg/dl and creatinine 1.6 mg/dl) was resolving few days after admission. Serum sodium was 137 meq/L, and potassium was low (2.4 meq/L). SPO2 was 86-90% with PO2 of 66.2 mm Hg in room air. Liver functions were normal except for high lactate dehydrogenase (427 IU/L). Echocardiography revealed normal cardiac function with no underlying structural abnormality and ejection fraction of 60%. X-ray revealed fracture shaft of humerus with multiple lytic lesions (Figure 1). Preliminary diagnosis of American Society of Anesthesiologist (ASA) Physical Status Grade III with left pathological humerus fracture with multiple myeloma with chest wall metastasis with resolving acute kidney injury with somatoform disorder with probable difficult airway was made. She was then planned for open reduction and internal fixation with PHILOS plating. Challenges of increased risk for perioperative bleeding, chest infections, postoperative mechanical ventilation, deep vein thrombosis, and local anesthesia toxicity were anticipated. Therefore, we planned her under regional anesthesia with IBPB under ultrasound guidance with sedation. Even with IBPB, the risk of neurological sequelae particularly phrenic nerve blockade leading to respiratory compromise in the patient was possible. Possibility of requirement of general anesthesia (GA) and postoperative mechanical ventilation was also discussed. Written informed consent with the patient party was taken. On the day of surgery, in the operation theatre, a monitor was attached, and baseline vitals were taken. Ceftriaxone 1 g injection was given intravenously as prophylactic antibiotic. Preliminary scan was done to visualize brachial plexus in the interscalene groove (Figure 2) with ultrasound (Samsung My SONO U6) with linear probe. Location of the phrenic nerve was scanned between the anterior scalene and sternocleidomastoid muscle. Using the in-plane technique and taking care of asepsis, ultrasound compatible needle (PAJUNK, SONOPLEX STIM, 20G x 150 mm) was used to infiltrate the three trunks, mostly superior and middle trunk and lower trunk the least (Figure 3), with total 20 ml local anesthetic (Two 10 ml syringe each containing 5 ml of 1% lignocaine with adrenaline (1 : 100000) and 5 ml of 0.25% bupivacaine plain after dilution). At the time of injection and spread of local anesthetics, caution was taken to visualize the tip of the needle below the superior trunk in the interscalene groove and away from the plane of anterior scalene and sternocleidomastoid to avoid phrenic nerve blockade (Figure 3). At the same time, extra care was taken to use as minimum injection pressure as possible while injecting 5 ml aliquots of local anesthesia. Sensory block was ensured with the pinprick method in the related dermatome. Motor block for radial, ulnar, and median was also present, with minimum handgrip. Clinically, respiratory movement was symmetrical bilaterally and adequate to maintain the oxygen saturation. However we did not measure the diaphragmatic excursion on the blockade side or did any pre- and postspirometry tests to notice the changes. Dyspnea, hoarseness of voice, hiccups, or features of Horner's syndrome were not noted. The patient was sedated using propofol injection at a rate of 50 mcg/kg/min via an infusion pump, and supplemental oxygen was given via facemask at 5 L/min. Fentanyl 50 mcg injection was also given intravenously prior to block to ensure proper pain management. Her vitals remained stable throughout the intraoperative period of 3 hours, and her urine output was maintained 1 ml/h (total 150 ml). Postoperative pain catheter was not placed due to lack of equipment, inadequate training, untrained nursing staff, and risk of high dose of local anesthetics aggravating kidney injury in the postoperative period due to prolonged infusion. In the postoperative ward, pain was managed using multimodal approach with paracetamol 1 g injection every 6 hours and fentanyl infusion at 20 mcg/h. Supplemental oxygen was continued for another 6 h postoperatively at the rate of 2 L/min via nasal prongs, and incentive spirometry was advised. Her Numeric Rating Pain (NRS) scale remained less than 4 out of total 10 mm throughout the first operative day. Complaints of dyspnea, hoarseness, hiccups, and signs of Horner's Syndrome were also not present during the same period. On the second postoperative day, paracetamol was continued with fentanyl as per required basis. Her NRS rating was 2 to 3 and was ambulating comfortably. She had early enteral feeding, mobilization with good compliance on incentive spirometry on the first postoperative day with no issues of postoperative nausea and vomiting. She was discharged on the 5th postoperative day with no issues of wound infections, and her renal function stayed with the normal limits.