ヒドロキシエチルデンプン
**ヒドロキシエチルデンプン (HES)** は、主にアミロペクチンから構成されるワキシーコーンスターチ由来の合成コロイド血漿増量剤です。獣医療の救急集中治療において、循環血液量減少の治療および膠質浸透圧の維持に使用されます。 **主な臨床的特徴:** * **血管内貯留性:** 晶質液と比較して、HESはより優れ、かつ持続的な血管内血漿増量効果をもたらします。 * **毛細血管漏出症候群:** 全身性炎症を伴う患者において、血管透過性を低下させ、炎症性メディエーターを抑制するのに役立ちます。 * **分子量と置換度:** 製品は平均分子量 (MW) と置換度 (DS) によって分類されます（例: HES 450/0.7、HES 130/0.4）。MWとDSが高いほど血管内半減期は延長しますが、血液凝固異常のリスクが高まります。
作用機序: HES acts as a synthetic colloid to expand plasma volume through oncotic forces. * **Oncotic Pull:** Large HES molecules remain in the intravascular space → **increase plasma oncotic pressure** → draw fluid from the interstitial space into the blood vessels → **expand circulating blood volume**. * **Enzymatic Degradation:** To prevent rapid breakdown, the glucose units of amylopectin are substituted with hydroxyethyl ether groups. * **Metabolism:** Larger molecules are slowly degraded by **serum alpha-amylase** into smaller fragments → fragments < 50,000 Daltons are rapidly excreted by the kidneys.
動物種別の用量
- Shock bolus (resuscitation) · 5-10 mL/kg · IV · once · Administer slower than in dogs to avoid nausea/vomiting.
- Infusion · 1-2 mL/kg/hr; not to exceed 10 mL/kg in a 24 hour period · IV · CRI · 24 hours
- Emergent situations / Colloid oncotic pressure support · 10/mL/kg/day · IV · slow bolus over 15-30 minutes OR 24-hour infusion
- Shock resuscitation · 20 mL/kg · IV · bolus · Slower in the cat. Rapid administration to cats can cause nausea and vomiting.
- Adult horses - volume support · 8-10 mL/kg/day · IV · daily
- Foals - rapid volume support · 3-5 mL/kg · IV · once · In addition to crystalloids.
- Hypo-oncotic, well hydrated horses · 0.5-1 mL/kg per hour, up to 10 mL/kg/day · IV · CRI
- Volume replacement · 3-10 mL/kg · IV · once · Total daily doses of 10 mL/kg should not be exceeded due to risk for coagulopathies.
- Fluid resuscitation and management of hypoproteinemia · 8-10 mL/kg IV bolus or as a CRI at 0.5-1 mL/kg/hr (max. of 10 mL/kg/day) · IV · bolus or CRI
- Volume replacement · 10-15 mL/kg over 20-40 minutes, up to four times daily, OR 10-15 mL/kg bolus over 20-40 minutes followed by 1-2 mL/kg/hr continuous rate infusion · IV · up to q6h or CRI · Recommended maximum dose is 20 mL/kg/24 hours, though author notes exceeding this without side effects.
投与経路
禁忌
- Severe heart failure
- Severe bleeding disorders
- Oliguric or anuric renal failure
有害事象
- Coagulopathies (prolonged PT/PTT, altered Factor VIII and von Willebrand Factor)
- Nausea and vomiting (especially in cats if administered too rapidly)
- Volume overload leading to pulmonary edema
- Hypersensitivity/anaphylactic reactions (rare)
- Falsely elevated serum amylase levels
- Transient increases in indirect serum bilirubin
- Potential risk for acute kidney injury (extrapolated from human data)
薬物相互作用
- Whole Blood / Red Blood Cells · Do not administer Hextend simultaneously with blood through the same administration set due to a risk of coagulation.
モニタリング
- Fluid status (blood pressure, heart rate, capillary refill time, central venous pressure)
- Coagulation parameters (PT, PTT, platelet count), especially in high-risk patients or with high doses
- Clinical signs of pulmonary edema (respiratory rate/effort, lung auscultation)
- Blood gases
- Renal function (BUN, creatinine, urine output)
過量投与
Overdosage primarily results in **intravascular volume overload**, which can lead to pulmonary edema and congestive heart failure in susceptible patients. Treatment involves stopping the infusion, carefully monitoring fluid status, and administering diuretics (e.g., furosemide) if pulmonary edema develops.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。