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Thyroid hormone supplementation for the prevention of morbidity and mortality in infants undergoing cardiac surgery

  • Review
  • Intervention

Authors


Abstract

Background

Paediatric studies have demonstrated that cardiopulmonary bypass is associated with a decline in thyroid hormone levels. Adult patients who undergo open heart surgery and receive triiodothyronine supplementation have demonstrated a dose-dependent increase in cardiac output which has been associated with an improved clinical outcome. Thyroid hormone supplementation in infants may also reduce postoperative morbidity and mortality.

Objectives

To determine if perioperative thyroid hormone supplementation or replacement in infants undergoing cardiac surgery on cardiopulmonary bypass improves postoperative and longer term morbidity and mortality.

Search methods

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of The Oxford Database of Perinatal Trials, MEDLINE (1966 - October 2007), EMBASE (1980 - October 2007), CINAHL (1982 - October 2007), The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2007), previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants and journal handsearching in the English language.

Selection criteria

All trials using random allocation to perioperative thyroid hormone therapy (supplementation or replacement) compared to control (placebo or no therapy) in infants (birth to one year of age) undergoing cardiac surgery requiring cardiopulmonary bypass. Thyroid hormone therapy must be triiodothyronine.

Data collection and analysis

Primary clinical outcomes included measures of postoperative morbidity and mortality. The standard methods of the Cochrane Neonatal Review Group were used in the assessment of trial quality. Treatment effects were expressed using relative risk (RR) and mean difference (MD).

Main results

Three small studies were identified that tested perioperative thyroid hormone supplementation or replacement in infants aged less than one year undergoing cardiac surgery (Mackie 2005; Portman 2000; Chowdhury 2001). In the Chowdhury 2001 study, a subgroup of nine neonates was eligible for this review.

No deaths occurred during the studies. Chowdhury 2001 and Mackie 2005 found no significant effect of perioperative thyroid hormone supplementation in neonates on either length of hospital stay or duration of mechanical ventilation. Portman 2000 found no significant difference in dopamine requirements for the treatment versus control groups for the first 24 hours postoperatively and in Mackie 2005 for up to five days, while in the Chowdhury neonatal subgroup, inotrope requirements were significantly lower in the treatment group. Portman 2000 reported significant differences between the two groups at one and 24 hours postoperatively for free T3 and at one hour postoperatively for total T3 levels. Total T4 levels showed no significant difference between groups, either pre-cardiopulmonary bypass or up to 72 hours postoperatively. In Mackie 2005, total and free T3 levels were significantly higher in the T3 group at 24, 48 and 72 postoperative hours but were similar between groups immediately before and after CPB and at seven postoperative days. The study drug was ceased 33 hours prematurely in one subject in Mackie 2005 due to a seven minute episode of ectopic atrial tachycardia.

Authors' conclusions

At present, there is a lack of evidence concerning the effects of triiodothyronine supplementation in infants undergoing cardiac surgery. Further randomised controlled trials which include sufficiently large subject numbers in a variety of different age strata (neonates, infants and older children) need to be undertaken.

摘要

背景

補充甲狀腺賀爾蒙用於預防嬰兒心臟手術之罹病率及致死率

在兒科研究中已證明體外循環與甲狀腺賀爾蒙下降有關.接受開心手術之成人病患使用三碘甲狀腺素補充,會出現與劑量相關之心輸出量增加並有較好的臨床結果.補充甲狀腺賀爾蒙於嬰兒可能也會減少術後罹病率跟致死率.

目標

研究嬰兒在接受體外循環下的心臟手術時,甲狀腺賀爾蒙補充或替代性使用,是否可改善術後及長期的致病率和致死率.

搜尋策略

使用the Cochrane Neonatal Review Group 的標準搜尋方法.搜尋包括The Oxford Database of Perinatal Trials, MEDLINE (1966 – 2003 十二月), EMBASE (1980 – 2003 十二月), CINAHL (1982 – 2003 十二月), The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003), 以前的回顧(包含交互引用文獻,摘要,會議,研討會摘要,專家資訊和手動搜尋英文期刊)。

選擇標準

所有採隨機分派至手術期甲狀腺賀爾蒙療法 (補充或替代品) 或對照組 (安慰劑或沒有治療), 對象為接受體外循環下心臟手術的嬰兒 (1歲以下). 甲狀腺賀爾蒙必須使用三碘甲狀腺素.

資料收集與分析

主要臨床結果包含術後罹病率和死亡率.使用the Cochrane Neonatal Review Group 的標準方法評估試驗品質.以相對風險(RR)和平均差(MD)表示治療療效

主要結論

找到2個非常小型的試驗,比較手術期甲狀腺賀爾蒙補充或替代品,對象為接受心臟手術的嬰兒 (1歲以下). (Chowdhury 2001; Portman 2000). Chowdhury 2001的研究中, 9名新生兒的次樣本可納入本回顧.兩試驗中都沒有死亡案例. Chowdhury 2001發現手術期甲狀腺賀爾蒙補充,對新生兒的住院期長短和人工機械通氣治療時間長短都沒有顯著效果. Portman 2000結果顯示:術後24小時內,治療組與對照組多巴氨需求量沒有顯著差異, 但是Chowdhury 的新生兒研究對象中,治療組的強心藥物需求顯著下降. Portman 2000 指出術後1和24小時,兩組游離T3有顯著差異,而術後1小時,兩組總T3有顯著差異. 兩組體外循環手術前和術後72小時內的總T4則都沒有顯著差異

作者結論

目前缺少證據證明三碘甲狀腺素補充品對接受心臟手術之嬰兒有療效.需進行更多隨機對照試驗,有夠大的樣本數並含蓋各年齡層 (新生兒,嬰兒,再大一點的小孩)

翻譯人

本摘要由成功大學附設醫院尹子真翻譯。

此翻譯計畫由臺灣國家衛生研究院 (National Health Research Institutes, Taiwan) 統籌。

總結

目前缺少證據來倡導使用三碘甲狀腺素補充品來預防接受體外循環之嬰兒於術後的得病率和死亡率.甲狀腺賀爾蒙是細胞代謝和維持血流穩定的必需品.體外循環後會有暫時性後天低甲狀腺素的狀況發生,被認為跟心輸出量降低,左心功能不全,血管阻力上升和通氣受損有關.補充甲狀腺賀爾蒙被認為可能可改進術後狀態.考量利敝之下,本回顧突顯以三碘甲狀腺素對接受體外循環手術之嬰兒做補充治療是缺乏證據的

Plain language summary

Thyroid hormone supplementation for the prevention of morbidity and mortality in infants undergoing cardiac surgery

There is insufficient evidence to advocate the use of triiodothyronine supplementation for the prevention of postoperative morbidity and mortality in infants who undergo cardiopulmonary bypass.Thyroid hormones are integral in cellular metabolism and haemodynamic stability. A transient acquired hypothyroidism occurs after cardiopulmonary bypass and is thought to be associated with low cardiac output, left ventricular dysfunction, increased vascular resistance and impaired ventilatory drives. Thyroid hormone supplementation has been postulated as a possible therapeutic option to improve postoperative outcome measures. This review highlights the lack of evidence concerning the benefits and harms of triiodothyronine supplementation in infants who undergo cardiopulmonary bypass.