Thyroid hormone dose escalation in hypothyroid patients undergoing general anaesthesia and major surgical procedures and it’s impact on clinical outcome

Abstract

Background: Surgical stress in patients undergoing general anaesthesia has been associated with the changes in thyroid function tests, and patients may suffer from a state of low T3 syndrome without pre-existing hypothalamic-pituitary and thyroid gland dysfunction (sick euthyroid syndrome) which can lead to delayed recovery from general anaesthesia.

Objectives: To assess the effect of increasing dose of thyroid hormone on the perioperative outcome of patients with known hypothyroidism undergoing major surgical procedures under general anaesthesia

Study design: Randomized case-control study.

Participants: 66 patients including 14 males and 52 females.

Methodology: Patients were assigned into 3 groups

Group 1: Hypothyroid patients who received twice the usual dose of thyroid hormone before surgery

Group 2: Hypothyroid patients who received the usual dose of thyroid hormone before surgery.

Group 3: Euthyroid patients who did not receive thyroid hormone

The patient groups were compared on the basis of different parameters like pre-operative, intraoperative and postoperative hemodynamics, thyroid function tests, Modified Aldrete score, Wrench shivering score, extubation quality scale, recovery from anaesthesia, consciousness level etc.

Results: In our study, we found that patients who received an escalated dose of thyroid hormone showed better results in terms of thyroid function test. They had less postoperative shivering as compared to other groups (p value < 0.05). Their extubation quality was better than the other two groups. They also had better Modified Aldrete score (p value < 0.05) and better consciousness level as compared to the other two groups.

Conclusions: We conclude that there is a great benefit in supplementing hypothyroid patients with an escalated dose of thyroid hormone preoperatively.

Implications: Preoperative thyroid hormone dose escalation can prove beneficial in preventing sick euthyroid syndrome in patients undergoing major surgical procedures under general anaesthesia however more studies in future are warranted before it can be universally accepted.