수술 후 수액, Postsurgical fluids

Crystalloids, blood products, colloid는 수술 후 환자에서 전형적으로 공급되는 수액입니다. 손실되는 체액의 유형과 양에 따라 공급되는 수액의 선택, 양, 공급 속도가 결정됩니다.

Crystalloids, blood products, and colloids are the replacement fluids typically administered to postoperative patients. It is important to consider the type and volume of fluid that was lost, which will help guide the choice of fluid, volume of fluid, and speed of fluid replacement.

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수술 후 공급되는 수액의 종류와 조성은 다음과 같습니다.

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Fluids for postoperative replacement and maintenance therapy

Solution (US trade name)	Sodium (mEq/L)	Potassium (mEq/L)	Chloride (mEq/L)	Lactate (mEq/L)	Acetate (mEq/L)	pH	Osmolarity (mOsm/L)
0.9% Sodium Chloride	154	0	154	0	0	5.5	308
Lactated Ringer's	130	4	109	28	0	6.5	273
5% Albumin (human)	130 to 160	≤2	Varies	0	0	6.9	300
Plasma-Lyte	140	5	98	0	27	7.4	294

US: United States.

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Crystalloids는 수술 후 단순 수액 공급 시 선택되는 수액입니다. Starch solutions은 수술 중 사용되더라도 수술 후 volume expansion 목적으로 일반적으로 사용되지 않습니다. 그 이유는 비정상적인 응고를 초래하여 출혈 합병증을 일으킬 수 있기 때문입니다.

Crystalloids remain the fluid of choice for simple fluid replacement following surgery. Although used intraoperatively, starch solutions are notcommonly used in postoperative surgical patients for volume expansion as they may result in abnormal coagulation, which can contribute to bleeding complications.

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Normal saline (Na = 154 mEq/L), Lactated Ringer's solution (Na = 130 mEq/L), Plasma-Lyte (Na = 140 mEq/L)는 나트륨 함량이 혈청 삼투압을 유지시키기 때문에 널리 사용되는 제제입니다. Lactated Ringer's와 normal saline의 pH는 신체 pH보다 낮아서 산-염기 이상을 초래할 수 있습니다. Lactated Ringer's solution의 lactate는 bicarbonate로 바뀌어 buffer 역할하지만 이것의 대사와 제거는 적절한 간과 콩팥 기능에 의존합니다. Plasma-Lyte가 포함하고 있는 acetate도 bicarbonate로 바뀌어 buffer 역할을 하지만 간과 콩팥 기능에 의존하지는 않습니다.

Normal saline (ie, 0.9% sodium chloride; Na = 154 mEq/L), Lactated Ringer's solution (Na = 130 mEq/L), and Plasma-Lyte (Na = 140 mEq/L) are widely used because their sodium content maintains serum osmolarity, which helps retain water in the vascular space and facilitates volume expansion. The pH of Lactated Ringer's and normal saline is below physiologic pH, which also contributes to acid-base abnormalities. The lactate in Lactated Ringer's is converted to bicarbonate, which serves as a buffer, but its metabolism and clearance depend on adequate liver and kidney function. Plasma-Lyte contains acetate, a buffer, which is quickly converted to bicarbonate in most tissues, independent of the liver and kidneys [13]. Plasma-Lyte is more expensive than normal saline or Lactated Ringer's, which limits its use.

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●Normal saline (0.9%) is particularly useful in cases of chloride and volume loss as well as alkalosis (eg, vomiting). It contains the greatest concentration of sodium, repletes chloride loss, and will reverse contraction alkalosis.

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●Normal saline (0.9%) is used in association with blood transfusion, particularly rapid transfusion, because it does not contain additives like calcium, potassium, or magnesium. Lactated Ringers and Plasma-Lyte contain these additives, which may not be compatible with all blood products and can result in red blood cell lysis, clot formation in the tubing, and electrolyte chelation.

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●Normal saline (0.9%) is used for head-injured patients, in whom hypernatremia is preferable to hyponatremia or lowering the serum osmolarity. The brain does not tolerate edema well; maintaining a normal (or elevated) sodium ensures that cerebral edema is minimized.

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●Lactated Ringer's and Plasma-Lyte should be avoided in patients with hyperkalemia as they both contain potassium. Similarly, in patients with poor renal function, these choices are typically avoided in order to avoid hyperkalemia.

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●Large volumes of normal saline are undesirable as they will result in hyperchloremic acidosis and renal vasoconstriction . However, in some cases of renal and/or liver dysfunction, a provider may have no other choice but to use 0.9% saline. A chloride-restrictive approach may reduce the incidence of acute kidney injury.

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●For patients with bicarbonate loss (eg, pancreatic fistula, bladder-drained pancreas transplant), bicarbonate replacement therapy may be administered intravenously in a continuous fashion. Sodium bicarbonate is commonly added to replacement fluids in increments of 50 mEq/L. The fluid vehicle is chosen to achieve the desired fluid sodium. For example, 150 mEq/L of sodium bicarbonate will provide 150 mEq of sodium per liter, which is nearly equivalent to 0.9% saline (154 mEq/L). As such, it is mixed in sterile water or 5% dextrose in water to avoid further sodium administration.

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●Hypertonic saline (3% sodium chloride) is being used for the resuscitation of trauma patients whose abdomens are maintained open with a temporary abdominal closure device. In this highly selective population, volume overload results in delayed primary fascial abdominal closure and complications of open abdomen (eg, enteroatmospheric fistula). Inspired by a promising early report, similar encouraging reports have suggested that the complications associated with hypertonic saline resuscitation (hyperchloremia, hypernatremia, hyperosmolar acidosis) are well tolerated in this patient population [21]. Although this is not the standard of care, it remains a promising alternative to standard resuscitation and is supported by one systematic review.

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Colloid solutions can also be used for volume expansion. The main colloid used in postoperative patients is albumin, most commonly in the setting of severe malnutrition or liver failure. It may maintain oncotic pressure better than crystalloid. However, the effects of albumin are short-lived since it remains in the vascular space only for hours. The critical care literature suggests that there is no benefit to using albumin. A systematic review and meta-analysis from 1998 reported that albumin did not reduce mortality when compared with crystalloid. Later trials have also not demonstrated any benefit with respect to perioperative mortality with the use of albumin. Caution is advised with the use of large volumes of albumin; hyperoncotic albumin resuscitation was associated with increased risk of death in an international prospective study. Similarly, the use of albumin in neurologic injury is associated with increased mortality, likely due to the secondary increase in intracranial pressure that results . Other colloid solutions include gelatins, dextrans, and starches. The use of these agents in postoperative patients is very limited as their rheologic and anticoagulant effects are typically unwelcome. Similarly, they can incite anaphylactic reactions. In a Cochrane review of surgical and critically-ill patients, no colloid was found to be superior in efficacy or safety.

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The best volume expanders in postoperative patients are blood products, particularly red blood cells and plasma. The risks associated with blood transfusion include transfusion-associated infection, lung injury, multiorgan failure, and systemic inflammatory response syndrome (SIRS). Thus, transfusion is limited to patients with accepted indications such as those undergoing resuscitation for ongoing large-volume bleeding, symptomatic anemia related to acute blood loss, and reversal of coagulopathy or thrombocytopenia that places the patient at increased risk for postoperative hemorrhage. For large-volume blood loss, the American College of Surgeon (ACS) Advanced Trauma Life Support (ATLS) protocol (10th edition) mandates an initial one-liter rapid infusion of warmed isotonic fluid followed by blood products. Although massive transfusion protocols vary widely in the United States, most trauma centers now use a balanced transfusion (1:1:1 ratio for plasma:platelets:red blood cells). In the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) study, a balanced transfusion was superior in achieving hemostasis and preventing death in trauma patients.

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REF. UpToDate 2019.08.13