Euthyroid sick syndrome in paediatric and adult patients requiring extracorporeal circulatory support and the role of thyroid hormone supplementation: a review

Indications for Intravenous T3 and T4

Therapy with thyroid hormones normally is restricted to substitution therapy of patients with primary or secondary hypothyroidism. Typically, thyroid hormones are given orally. There are few indications for intravenous use of thyroid hormones. Indications for parenteral application are insufficient resorption of oral medications due to alterations of the gastrointestinal tract, partial or total loss of consciousness, sedation in the intensive care unit or shock. In almost all cases, levothyroxine is the therapy of choice including congenital hypothyroidism. In preterm infants with an altered thyroid hormone status, studies with thyroid hormones including intravenous liothyronine showed a normalisation of T3 levels and in some cases an amelioration of parameters of ventilation. A benefit for mortality or later morbidity could not be seen. Effects on neurological improvements later in life are under discussion. Decreased thyroid hormone levels are often found after cardiac surgery in infants and adults. Intravenous therapy with thyroid hormones improves the cardiac index, but in all other parameters investigated, no substantial effect on morbidity and mortality could be demonstrated. Oral liothyronine therapy in these situations was equivalent to an intravenous route of application. In myxoedema coma, intravenous levothyroxine is given for 3 to 10 days until the patient can take oral medication and normal resorption in the gastrointestinal tract is achieved by restoring at least peripheral euthyroidism. Intravenous levothyroxine is the standard in treating patients with myxoedema coma. A protective effect on the heart of i.v. levothyroxine in brain-dead organ donors may be possible.

Thyroid hormone levels paradox in acute ischemic stroke

Objective

Accumulating evidence has suggested that thyroid hormone levels affect the prognosis of acute ischemic stroke (AIS), but the results have been inconsistent.

Methods

Basic data, neural scale scores, thyroid hormone levels, and other laboratory examination data of AIS patients were collected. The patients were divided into excellent and poor prognosis group at discharge and 90 days after discharge. Logistic regression models were applied to evaluate the relationship between thyroid hormone levels and prognosis. A subgroup analysis was performed based on stroke severity.

Results

A number of 441 AIS patients were included in this study. Those in the poor prognosis group were older, with higher blood sugar levels, higher free thyroxine (FT4) levels, and severe stroke (all p < 0.05) at baseline. Free thyroxine (FT4) showed a predictive value (all p < 0.05) for prognosis in the model adjusted for age, gender, systolic pressure, and glucose level. However, after adjustment for types and severity of stroke, FT4 showed insignificant associations. In the severe subgroup at discharge, the change in FT4 was statistically significant (p = 0.015), odds ratio (95% confidence interval) = 1.394 (1.068-1.820) but not in the other subgroups.

Conclusions

High-normal FT4 serum levels in patients with severe stroke receiving conservative medical treatment at admission may indicate a worse short-term prognosis.

Predictors of Low Cardiac Output Syndrome in Infants After Open-Heart Surgery

OBJECTIVE

To evaluate the predictors of low cardiac output syndrome (LCOS) in infants with congenital heart disease (CHD) after cardiopulmonary bypass (CPB).

STUDY DESIGN

A total of 217 infants were enrolled and classified according to whether they developed LCOS after cardiac surgery. Each infant's preoperative and intraoperative clinical variables were collected.

RESULTS

The incidence of LCOS was 28.11% in our study. The univariate analysis showed that the LCOS group was younger than the non-LCOS group (25.69 ± 25.01 days vs. 44.45 ± 26.97 days, P < 0.001), with a higher proportion of neonates (60.7 vs. 27.6%, P < 0.001) and a higher proportion of patients with a RACHS-1 score ≥4 (50.8 vs. 17.9%, P < 0.001). A lower weight (3.70 ± 0.74 vs. 4.23 ± 1.10 kg, P = 0.001), longer ACC time (61.96 ± 21.44 min vs. 41.06 ± 18.37 min, P < 0.001) and longer CPB time (131.54 ± 67.21 min vs. 95.78 ± 62.67 min, P < 0.001) were found in the LCOS group. The levels of free triiodothyronine (FT3) (4.55 ± 1.29 pmol/L vs. 5.18 ± 1.42 pmol/L, P = 0.003) and total triiodothyronine (TT3) (1.80 ± 0.56 nmol/L vs. 1.98 ± 0.54 nmol/L, P = 0.026) were also lower in the LCOS group. The multivariate binary logistic regression analysis and receiver operating characteristic (ROC) indicated that the ACC time, FT3 level and body weight were independent predictors of LCOS.

CONCLUSIONS

In our patient population, we first propose that preoperative FT3 can predict the occurrence of postoperative LCOS. ACC time, FT3 level and body weight are independent predictors of LCOS and maybe helpful in reducing the incidence of postoperative LCOS in the future.