How does hextend work
Colloid solutions broadly partitioned into synthetic fluids such as hetastarch and natural such as albumin exert a high oncotic pressure and thus expand volume via oncotic drag. What is the medical use of Hetastarch? Hetastarch is used to treat or prevent hypovolemia decreased blood plasma volume, also called "shock" that may occur as a result of serious injury, surgery, severe blood loss, burns, or other trauma.
Is blood a colloid? Colloids contain larger insoluble molecules, such as gelatin; blood itself is a colloid. Is Gelofusine a colloid? As a result, it causes an increase in blood volume, blood flow, cardiac output, and oxygen transportation. What is a colloid in medicine? What is a synthetic colloid?
Natural colloids include blood products plasma, whole blood and albumin solutions. Synthetic colloids include hydroxyethyl starch HES solutions as well as the less commonly used dextrans or gelatins.
Artificial colloids were created as an alternate resuscitation fluid to albumin. Is plasma a colloid solution? What is a crystalloid solution? A crystalloid fluid is an aqueous solution of mineral salts and other small, water-soluble molecules.
Most commercially available crystalloid solutions are isotonic to human plasma. With an guage catheter, the user could expect a minimum infusion time for Hextend of just less than 5 minutes with optimal conditions and no pressure infusion. While the infusion of Hextend will be slower than its potential maximum flow rate, it would be given far earlier in the course of casualty treatment than it would generally.
As long as Hextend remains the recommended fluid for resuscitation, this method should become the standard means by which TXA and Hextend are given on the battlefield.
That instrument was used by Trissel et al as a secondary means to assess subvisual precipitate. It should be noted that in the original study, no medication without a visible precipitate was positive on this additional screening. However, the authors recommend additional independent verification of these results before any change in clinical practice.
Finally, a limitation that also applied to all previous similar research on this topic is that physical compatibility does not necessarily correlate to chemical stability. However, it is considered rare for such a concern to manifest in the short time these agents would be in contact in vitro, and is not typically evaluated. To conclude, there was no demonstrated evidence of incompatibility by either visual inspection or with a basic turbidimeter between Hextend and TXA.
With replication of this experiment, the authors strongly urge the elimination of the current caveat against coadministration. Further, the authors recommend that the standard method of TXA administration on the battlefield be changed to simultaneous coadministration using the piggyback infusion method. The authors would like to thank the U. Army Special Operations Command Surgeon's office for their encouragement. Butler FK Fluid resuscitation in tactical combat casualty care: brief history and current status.
J Trauma ; 70 : S11 — 2. Google Scholar. Food and Drug Administration: FDA Safety Communication Boxed Warning on increased mortality and severe renal injury, and additional warning on risk of bleeding, for use of hydroxyethyl starch solutions in some settings. J Spec Oper Med ; 14 3 : 13 — CRASH-2 trial collaborators Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage CRASH-2 : a randomised, placebo-controlled trial.
Lancet ; : Arch Surg ; : — 9. Int J Pharm Compd ; 5 1 : 69 — J Thorac Cardiovasc Surg ; : — J Trauma Acute Care Surg ; 74 3 : — 9 ; discussion — Ann Card Anaesth ; 15 2 : — Int J Clin Exp Med ; 8 4 : — J Spec Oper Med. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.
Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Oxford Academic. Ahmad H. Yassin, DO. Donald E. Cite Cite Nicholas M. Select Format Select format. Also included is an order of precedence for resuscitation fluid options.
Hetastarch is retained as the preferred option over crystalloids when blood products are not available because of its smaller volume and the potential for long evacuations in the military setting. The single major cause of death over 6 h in this group is haemorrhage either as a primary insult or secondary to trauma induced coagulopathy. Fluid resuscitation of the right type and in the right dose reduces mortality and morbidity [ 2 ].
The concept of fluid resuscitation for haemorrhagic shock has changed from large volume crystalloid resuscitation, to small volume colloid resuscitation and use of blood or blood products at the earliest—even as a primary resuscitative fluid and early use of anti-fibrinolytic such as tranaxemic acid all of which form a part of damage control resuscitation [ 3 ]. Damage control resuscitation DCR comprises of hypotensive resuscitation and haemostatic resuscitation which aims to achieve the following:.
A restricted increase in intravascular volume targeting a systolic blood pressure SBP up to 90 mmHg improvement of mental status or a weakly palpable radial pulse as a surrogate marker so as to minimizes adverse effects of edema and prevent dilutional coagulopathy caused by large volume crystalloid resuscitation, reduce the incidence of a re-bleed due to clot dislodgement which increasingly occurs over systolic blood pressures of 90 mm Hg while maintaining perfusion to vital organs.
This commentary reviews the available fluids used in resuscitation and correct recommendations in vogue in management of combat casualties. Crystalloids in a ratio of 3 ml of crystalloid for every ml of shed blood are used commonly as the first line of fluid in haemmorghic shock. Crystalloids however, have no role in DCR as short term increase in intravascular volume are negated by risk of pulmonary oedema, displacement of forming clots at sites of vascular injury, abdominal compartment syndrome, acidosis, worsening of cerebral oedema, and dilutional coagulopathy [ 4 ].
In fact there is Level B clinical evidence that large volume crystalloid resuscitation reduces survival [ 5 ]. If the only available fluid is crystalloid then, ringer lactate is preferred over NS because it does not produce the hyperchloremic acidosis and the concern of lactate in RL causing acidosis is some what unfounded [ 6 ].
Plasma-lyte A if available offers some benefit over RL [neutral ph of 7. RL is more acidic, slightly hypotonic and contains calcium which may cause blood to coagulate if used with packed red blood cells PRBC or whole blood].
Hypertonic saline dextran HSD and hypertonic saline HS improve hemodynamic and metabolic responses, modulate immune function and reduce brain oedema in a number of experimental injury models. However a cochrane study concluded that there is no evidence that hypertonic crystalloids are better than near isotonic crystalloids for fluid resuscitation in trauma [ 7 ].
Colloids [Gelatins, various Hydroxy ethyl starches HES and albumin] are more effective than crystalloids for expanding the plasma volume because they contain large, poorly diffusible solute molecules that create an osmotic pressure to keep water in the vascular space with less extravasation of fluid into the lung than RL with a resulting improvement in oxygenation [ 8 ].
The smaller volume of colloids required for an equivalent and extended expansion of the intravascular space as compared to crystalloids offers a logistical advantage.
However their propensity to cause renal damage is still controversial with some studies reporting no renal damage [ 7 ] while others did [ 9 ]. The FIRST trial reported that hydroxyl ethyl starch improves the renal function and lactate clearance when used for resuscitation in patients of penetrating trauma [ 9 ].
There is Level B evidence that Hextend used in two aliquots of ml each to supplement fluid resuscitation in trauma patients is safe and does not result in a coagulopathy [ 11 , 12 , 13 ]. The warning noted an increased risk in mortality and renal replacement therapy associated with the use of these products as used to treat critically ill patients [ 14 ].
However this communication did not mention the use of these products in the prehospital resuscitation of trauma patients, nor did it address the known increase in mortality and fluid overload complications resulting from the alternative use of large volume crystalloids in such patients Use of albumin for resuscitation in patients with associated traumatic brain injury TBI resulted in increased mortality [ 15 ].
This fact precludes its use in combat casualty care as haemorrhagic shock and TBI often co-exist. Resuscitation with whole blood, component therapy and plasma in that order best fulfil the criteria of DCR as they contribute to haemostasis in varying degrees while increasing the intravascular volume. There is some debate on the ability of Warm fresh whole blood and stored whole blood in correcting coagulopathies.
Certain authors advocate fresh warm whole blood FWWB to more efficient than component therapy or stored whole blood in correcting coagulopathy as it has fresher RBC and better functioning and concentration of platelets and plasma [ 16 ].
The amount of fresh warm whole blood transfused is independently associated with improved h and day survival and the amount of stored red blood cells transfused is independently associated with decreased h and day survival for patients with traumatic injuries that require massive transfusion [ 17 ].
However few recent studies and reports have shown the efficacy of stored whole blood to be as good as FWWB [ 18 , 19 ]. The use of FWWB in combat casualty care may be warranted stored whole blood or PRBC at the level of the field surgical centre FSC since the supply of the latter is likely to be small and component therapy is unavailable.
In addition all military personnel should be tested for HIV and immunized against Hepatitis B prior to deployment. The two available brands currently available and are been used extensively in combat operations are LyoPlas and LyoPhil. DP offers the opportunity for both volume replacement and replacement of lost clotting factors and has a good safety record [ 20 ].
Thirty-eight percentage of combat casualties who require a transfusion have a coagulopathy [ 21 ] which increases mortality by three to sixfold [ 22 ] and plasma administration reduces the coagulopathy. LyoPlas also enables rapid treatment of coagulopathies without the need for complex logistics or thawing. Over , units have been transfused to date with no reports of major adverse complications to include viral transmission. The frequency of transfusion reactions approximates that of FFP.
Presently this product is not available in India. All efforts should be made to ensure the availability of this wonderful resuscitative option for the Armed Forces. Thus the preferred fluids for DCR in haemorrhagic shock in order of preference are as under in order of preference:. Combat casualties are initially managed in an austere environment and choice of fluid will very often be confounded by logistical issues. None the less all efforts should be made to ensure availability of blood, blood products and lyophilized plasma as far forward as possible to ensure best possible care to combat casualties.
Early use of tourniquets, active and passive warming devices and early use of tranaxemic acid [ 22 ] when indicated play an important role in salvaging combat casualties suffering from haemorrhagic shock. Fluid resuscitation strategies for combat casualties need to be urgently refined to keep pace with current recommendation.
Large volume crystalloid resuscitation which is still in vogue in the most situations in combat need to be replaced with low volume colloid resuscitation and one of plasma or FWWB as forward in the field as possible to satisfy the arms of DCR namely the hypotensive resuscitation and haemostatic concerns.
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