Effect of intrapleural povidone-iodine lavage on thyroid hormones in thoracic surgery

Povidone-iodine (PI) is an effective disinfectant used in many surgical operations. It is known that PI is absorbed by the skin after application. Absorption is even greater in infants, as their skin is thinner and more permeable. Iodine absorption in the orbita, neck and during abdominal surgery has been previously investigated, but such a study has not been performed for the pleura, which has a greater area and capacity for absorption. In this study, we investigated the effect of intraoperative povidone-iodine lavage on thyroid hormones during thoracic surgery.

Fifty patients without any thyroid pathology scheduled for thoracotomy were divided into 2 groups. Group A (n = 25) was given intraoperative saline lavage, while group B (n = 25) had povidone-iodine lavage. Levels of free T3 (FT3), free T4 (FT4) and thyroid-stimulating hormone (TSH) measured 1 day preoperatively and 1 day postoperatively were analyzed.

There was a statistically meaningful change in FT3 levels ( P = 0.033) between groups, but the measured changes in FT4 and TSH levels were not statistically significant ( P = 0.98 and P = 0.71, respectively). FT3 scores for group A were decreased postoperatively compared to the scores for group B, but all results were in normal ranges. In group A, the changes between preoperative and postoperative levels of FT3 and FT4 were statistically significant, while changes in TSH levels were not. In group B, changes in FT4 levels were statistically significant and changes in FT3 and TSH levels were not.

The scores show that the iodine absorbed by the pleura during intraoperative povidone-iodine lavage has an effect on thyroid function. Intrapleural PI lavage results in changes to some thyroid hormone levels due to pleural absorption. Thus, intrapleural PI lavage should be used with care.