右旋糖酐 70
**右旋糖酐 70 (Dextran 70)** 是一種高分子量合成膠體，主要用於**低血容性休克**的輔助治療。 * **臨床作用：** 它是一種成本相對較低的血漿體積擴充劑。雖然現代獸醫學中更常使用**羥乙基澱粉 (Hetastarch)**，但右旋糖酐 70 仍是快速擴充血管內體積的有效選擇。 * **成分：** 它是一種平均分子量為 70,000 道爾頓的支鏈多醣。 * **臨床要點：** 由於其分子較大，它在血管內停留的時間比晶體輸液（如乳酸林格氏液或生理食鹽水）更長，因此對於頭部外傷、肺挫傷或閉合性體腔出血的重症病患進行小體積復甦非常有效。
作用機制: **Dextran 70** exerts its effects through oncotic pull: * Acts as an artificial colloid → increases intravascular **colloid osmotic pressure (COP)**. * The high COP → draws fluid from the interstitial spaces into the vascular system. * This fluid shift → rapidly increases circulating blood volume → improves venous return, cardiac output, and systemic perfusion. * *Note:* Dextran 70 has a colloid osmotic pressure of 62 mmHg, which is significantly higher than normal canine plasma (approx. 20 mmHg).
各物種劑量
- Small volume resuscitation (hypovolemic shock, head injury, pulmonary contusions, oliguric renal failure) · 2-5 mL/kg over 1-5 minutes (after initial isotonic crystalloids 5-10 mL/kg). Repeat as needed until end-point of resuscitation is reached. · IV · As needed · Acute resuscitation · Reassess perfusion parameters between boluses.
- Volume expansion / Augment colloid oncotic pressure · 10 mL/kg/day; when acute resuscitation is required. May be given as a slow bolus over 30 minutes to an hour. May also be given as a constant rate infusion. · IV · q24h or CRI · As needed · Reduces the volume of crystalloids infused, thereby reducing hemodilution.
- Dehydration secondary to diarrhea (Calves) · 4-5 mL/kg over 4-5 minutes of a 6% dextran 70 in 7.2% NaCl solution. Follow immediately by oral administration of isotonic electrolyte solution. · IV · Once · One time only · To prepare: add 31.6 g NaCl to 60 mL syringe, draw 60 mL of 6% dextran 70 in 0.9% NaCl, dissolve, and filter through 0.22 micron filter. Give ONE TIME ONLY to avoid hypernatremia.
- Small volume resuscitation (hypovolemic shock, head injury, pulmonary contusions, oliguric renal failure) · 5 mL/kg over 1-5 minutes (after initial isotonic crystalloids 10-15 mL/kg). Repeat as needed until end-point of resuscitation is reached. · IV · As needed · Acute resuscitation · Reassess perfusion parameters between boluses.
- Volume expansion / Augment colloid oncotic pressure · 20 mL/kg/day; when acute resuscitation is required, may be given as a slow bolus over 30 minutes to an hour. May also be given as a constant rate infusion. · IV · q24h or CRI · As needed · Reduces the volume of crystalloids infused, thereby reducing hemodilution.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Preexisting severe coagulopathies
- Severe heart failure (due to risk of circulatory overload)
- Severe renal failure (oliguric/anuric, unless closely monitored)
- Intramuscular (IM) administration
不良反應
- Increased bleeding times (decreased von Willebrand's factor and factor VIII activity)
- Anaphylactoid reactions (rare in dogs, but higher incidence than hetastarch)
- Acute renal failure (rare)
- Volume overload / circulatory overload
- Gastrointestinal effects (nausea, vomiting, abdominal pain - reported in humans)
監測
- Perfusion parameters (heart rate, blood pressure, capillary refill time, mucous membrane color)
- Signs of fluid/circulatory overload (respiratory rate/effort, lung sounds)
- Coagulation status / bleeding times (if prolonged use or high doses)
- Renal function and urine output
過量
**Volume Overload:** Overdosage primarily results in circulatory/fluid overload. The drug must be dosed and monitored carefully. Treatment is supportive, potentially requiring diuretics (e.g., furosemide) if severe pulmonary edema or volume overload occurs.
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