Zinc lozenges help soothe postoperative sore throat after endotracheal intubation, a study has confirmed.
“Zinc does help and has no adverse side effects,” said Lydia Grondin, MD, associate professor of anesthesiology at the University of Vermont College of Medicine, in Burlington.
Zinc, which is involved in processes such as growth and tissue repair, is an effective antioxidant that protects sulfhydryl groups against oxidation and inhibits production of reactive oxygen. Since oral zinc sulfate has been shown to prevent oral mucositis, xerostomia, and pain associated with chemotherapy, Dr. Grondin wondered whether lozenges would help postoperative sore throat as well.
“Zinc is everywhere right now,” she said. “Could it help our patients?”
In the randomized, double-blind, placebo-controlled study, 79 patients were assigned to receive either placebo lozenges or 40-mg zinc lozenges at 30 minutes before an operation. They were asked about the severity of sore throat, rated on a 4-point scale—at zero, two, four and 24 hours after surgery—with a primary focus on four hours after surgery.
Dr. Grondin presented the research as one of the four top poster presentations at the 2016 joint meeting of the Society for Ambulatory Anesthesia and the American Society of Anesthesiologists. The presentation (poster 47) was given the meeting’s second-place Excellence and Innovation Award.
Directly after surgery, the incidence of sore throat was 0% in the zinc group and 24% in the control group (Figure 1). The highest rate of postoperative sore throat occurred two hours after surgery, at 10% in the zinc group and 34% in the control group. By postoperative hour 4, the incidence declined to 7% in the zinc group and 29% in the control group. By 24 hours after surgery, the incidence was 13% in the zinc group and 24% in the control group, which was not statistically significant.
Incidences of mild, moderate and severe sore throat were all lower in the zinc group than the placebo group.
Of note, patient weight, surgery duration and Cormack-Lehane classification were associated with an increased incidence of sore throat. Initial cuff pressure on the endotracheal tube and succinylcholine for intubation were associated with increased severity of sore throat.
“If a patient presents for intubation with a history of sore throat after intubation or they expect it may be a more difficult intubation, a preoperative zinc lozenge may be beneficial in preventing a sore throat in those situations,” Dr. Grondin said.
In the future, Dr. Grondin also would like to examine whether zinc would be helpful in treating a sore throat in the PACU.
“Based on personal experience, taking a zinc lozenge after endotracheal intubation does help,” she said. “It kicks in pretty quickly and seems to help with cellular healing.”