Hyponatremia and perioperative complications in patients with head and neck squamous cell carcinoma

Background. Recent studies suggest that hyponatremia is associated with perioperative morbidity and mortality after general surgical procedures, as well as mortality among medical inpatients. We investigated the association of hyponatremia with perioperative complications in patients undergoing surgical resection of head and neck squamous cell carcinoma (HNSCC). Methods. All patients with pathologically confirmed HNSCC undergoing either primary or salvage surgical resection from March 1, 2013, until May 31, 2014, at a single tertiary care academic center were included in this retrospective review. The primary outcome was 30-day mortality. Secondary outcomes included postoperative complications (respiratory, cardiac, renal, and wound), hospital and intensive care unit (ICU) length of stay, and need for blood transfusion. Results. Two hundred fourteen surgical patients with HNSCC were identified for analysis. Patient ages ranged from 22 to 100 years (mean, 67 years). One hundred thirty-eight men and 76 women were included. Primary tumor sites were oral cavity (47.7%), oropharynx (18.7%), larynx (12.6%), salivary glands (7.9%), cutaneous (7.5%), sinonasal (2.8%), and hypopharynx (2.3%). Surgical resections were balanced between primary (48.1%) and salvage (51.9%). Thirty-five patients (16.4%) carried a presurgical diagnosis of diabetes. Fifteen patients (7.0%) demonstrated preoperative hyponatremia, and 46 (24.9%) had postoperative hyponatremia. Within the primary outcome measure, no difference in mortality was identified. Complications were noted in 58 patients (27.1%), and were more frequent in hyponatremic patients, both preoperatively and postoperatively (60.0% and 41.3%, respectively). Binomial logistic regression demonstrated risk of complications significantly associated with preoperative hyponatremia (odds ratio [OR]=4.374; 95% confidence interval [CI]=1.231-15.545; p=.023), increasing age (OR=1.385; 95% CI=1.032-1.857; p=.030), and increasing length of surgery (OR=1.234; 95% CI=1.046-1.455; p=.013). Postoperative hyponatremia was associated with increased hospital length of stay (p=.034). Conclusion. Hyponatremia is a frequent electrolyte abnormality in patients with HNSCC. Both preoperative and postoperative hyponatremia are associated with perioperative morbidity, thus meriting intensive postoperative medical monitoring and treatment. Additional investigation is warranted to identify the pathophysiologic mechanisms behind this association. (C) 2015 Wiley Periodicals, Inc.