BACKGROUND: There is still a controversy about the best method for preoperative skin preparation (skin cleaning). The main antiseptic solution used in the cardiac surgery room is Povidone Iodine (PI), which is used to prepare the area to be operated on.
This study aimed to determine the urinary iodine level in children (newborns, infants, and toddlers) undergoing open and closed heart surgery, in whom preoperative skin preparation was performed using PI solution.
METHOD: This study was conducted over eight years on a total of 212 children who underwent cardiac surgery. A form was developed for each patient in which all their details, condition, and type of surgery were recorded. A urine sample was taken after the patients were anesthetized and before they were painted with PI through the urinary catheter that had to be attached to them for the cardiac surgery. The patients were then prepped with PI and draped and the surgery was performed. Afterwards, the second and third urine samples were taken 24 and 48 hours after the surgery from the urine collection bag. The samples were transferred to polyethylene tubes with screw caps in a cold box at -20 °C and sent to the iodine reference laboratory of the Endocrinology Research Center of Shahid Beheshti University. The samples were measured using the kinetic colorimetric reaction proposed by Sandell and Kolthoff after the acid digestion of urine.
RESULTS: A total of 212 patients (newborns, infants, toddlers) who underwent (open and closed) cardiac surgery entered the study, including 104 (49.1%) males and 108 (50.9%) females. The patients ranged in age from 1 day to 14 years (mean = 168 months). The urinary iodine level was 40.6±21.9 μgr/dl in the first stage (pre-surgery),204.1±92.5 μgr/dl in the second stage (24 hours post-surgery), and 130.3±56.2μgr/dl in the third stage (48 hours post-surgery).
Urinary iodine levels increased dramatically after PI use, and the second-stage urinary iodine changes (24 hours post-surgery) were in the excessive range according to the WHO classification, and they decreased gradually over the next 24 hours, but did not reach normal levels until 48 hours post-surgery. The difference between the samples was significant (P<0.05)
The samples were also separately analyzed by age group (groupA:0-2 years and group B: 2-14 years), which showed that transcutaneous iodine absorption and urinary iodine excretion were high in both age group.
CONCLUSION: In children, transcutaneous iodine absorption following preoperative skin preparation with PI (for cardiac surgery) is so high that its urinary excretion reaches an excessive level 24 hours after surgery and remains higher than normal until 48 hours’ post-surgery. Furthermore, the transcutaneous absorption of iodine is similar in the 0-2 and 2-14-year-old age groups, and the iodine level following its transcutaneous absorption is excessive in both age groups.