1. Subcutaneous Emphysema During Laparoscopy Tiffany Thornton, MD and Quinlan Amos, MD Department of Anesthesiology, University of Arizona Health Science Center, Tucson, AZ INTRODUCTION: Since the advent of laparoscopy, an increasing number of various laparoscopic procedures have been performed. Laparoscopy offers multiple benefits for patients, yet provides unique challenges for the anesthesiologist. CASE REPORT: The patient is a 48-year-old female who presented for a laparoscopic gastrojejunostomy due to malnutrition. Past surgical history included at least six prior abdominal surgeries. Induction and intubation were uneventful. The surgeons placed a Hasson port and two trochars and proceeded laparoscopically. Approximately 1.5 hours after induction, the patient’s ETCO2 increased from 30s to 50s-60s despite an increase in minute ventilation. Simultaneously, pulse increased from 60s to 100s and blood pressure increased. There was no change in pulse oximetry. Temperature remained around 36.5  C. Breath sounds were decreased on the left and left breast was noted to be tense. Peak pressures began increasing despite adequate relaxation and depth of anesthesia. Forty minutes later, the right breast was tense along with crepitus at the temporal area. ETCO2 continued rising, reaching a peak of 73 mm Hg. Differential diagnosis included pneumothorax, CO2 pulmonary embolus, malignant hyperthermia and subcutaneous emphysema. At this point the surgeons were asked to hold insufflation temporarily and subsequently decrease insufflation pressures. Chest radiograph in the OR prior to extubation showed extensive subcutaneous emphysema as well as pneumomediastinum. No definite pneumothorax was identified. The patient was successfully extubated and transported to PACU. On POD 2, the patient continued to have pain, particularly in her shoulder, but showed improvement in subcutaneous emphysema. DISCUSSION: Symptoms of hypercarbia include hypertension and tachycardia, which is related to release of epinephrine and norepinephrine. Treatment of hypercarbia involves increasing minute ventilation. Maintaining normocarbia may require an increase in minute ventilation by 20-30%. A reduction in insufflation pressure is also helpful in the management of hypercarbia during a laparoscopic case. Elevated ETCO2 typically returns to baseline levels within 10 minutes of terminating insufflation. Subcutaneous emphysema develops during laparoscopy from insufflated gas being driven by the insufflating pressure at the trochar insertion site to subcutaneous tissue planes. Risk factors for subcutaneous emphysema include ETCO2 > 50, operative time > 200 min and use of 6 or more REFERENCES: Gottlieb A, et al. Massive subcutaneous emphysema and severe hypercarbia in a patient during endoscopic transcervical parathyroidectomy using carbon dioxide insufflation. Anesthesia and Analgesia. 1997;May 84(5):1154-6 Murdock CM et al. Risk factors for hypercariba, subcutaneous emphysema, pneumothorax and pneumediastinum during laparoscopy. Obstetrics and Gynecology. 2000;May84(5):704-709 Pearce DJ. Respiratory acidosis and subcutaneous emphysema during laparoscopic cholecystectomy. Canadian Journal of Anesthesia. 1994 April;41(4):314-6 Wahba RW et al. Acute ventilatory complications during laparoscopic upper abdominal surgery. Canadian Journal of Anesthesia. 1996 Jan;43(1):77-83 surgical ports. Subcutaneous emphysema usually becomes evident approximately 45 minutes after the start of the procedure. Development of subcutaneous emphysema warrants further investigation to determine if pneumothorax or pneumomediastinum is present, particularly if the surgery is a laparoscopy involving the chest. If there is concern for pneumothorax along with respiratory distress or low oxyhemoglobin concentration at the end of the surgery, a chest radiograph prior to extubation is indicated. Subcutaneous emphysema may also herald a pneumothorax. Resolution of subcutaneous emphysema typically occurs within 1-2 days.