Fluid therapy for the traumatized patient

Abstract

Objective: To review the rationale behind and experiences with traditional and newly evolving concepts of fluid therapy in the traumatized patient, and to review conventional and novel fluid preparations for use in trauma resuscitation. Data sources: Human and veterinary clinical and research studies. Human data synthesis: Current treatment guidelines recommend aggressive fluid resuscitation with lactated ringers solution (LRS) or saline as optimum management of hemorrhagic shock in trauma, regardless of whether bleeding is controlled or not. The rationale behind this strategy is to restore intravascular volume as rapidly as possible to ensure adequate vital organ perfusion. Recently, this strategy has been challenged, especially in patients with uncontrolled hemorrhage, as neither laboratory evidence nor clinical trials support this practice. Current research indicates that vigorous fluid infusion may exacerbate bleeding and cause severe hemodilution, both impairing resuscitation outcome. As a result, a new line of thinking is emerging that balances the risks and benefits of intravenous volume infusion by offering the clinician alternative treatment strategies and emphasizes continuous endpoint‐oriented monitoring. ‘Hypotensive’ or ‘hypovolemic’ resuscitation techniques as well as initial volume replacement with fluids other than LRS or saline (e.g., hypertonic saline [HTS], HTS with dextran 70 [HTS‐D]) have been introduced in human medical practice as additional options for treatment of victims of trauma under certain circumstances. Clinical studies evaluating the use of hemoglobin‐based oxygen carriers (HBOCs) in the trauma setting are underway and may soon lead to an expansion of the fluid arsenal available to the clinician for treatment of trauma patients. Veterinary data synthesis: Based on available animal data, neither strict guidelines nor a clear fluid preference for resuscitation of traumatic shock have been defined. Although systematic clinical trials are missing, combinations of crystalloid and colloid (natural or artificial) appear to be as effective for resuscitation as crystalloid alone. Judicious use of an HBOC (e.g., Oxyglobin®) as a substitute for blood/red blood cells may be recommended in situations where whole blood or pRBCs are not or not yet available. Conclusions: The search for optimal methods of fluid resuscitation in trauma is ongoing. At this point the best solution is a differentiated approach to fluid therapy, one that tailors type and volume of resuscitation solution(s) used to the type and severity of injury in an individual patient and uses monitoring of perfusion and oxygenation parameters to guide resuscitation. Crystalloid fluids are effective for resuscitation but may need to be combined with or replaced by colloidal fluids in certain clinical situations.

Comparison of the effects of 7.2% hypertonic saline and 20% mannitol on whole blood coagulation and platelet function in dogs with suspected intracranial hypertension - a pilot study

“…Similarly, in vitro studies in dogs demonstrated that both mannitol and HTS have negative effects on coagulation in a dose-dependent fashion, although in vivo studies in dogs in a clinical setting are lacking [16, 17]. As a result, current guidelines for osmotherapy in dogs with ICH are largely extrapolated from experimental data and human literature [18, 19]. …”

Hypotension

“…[12][13][14] It is also important to recognize that once a "reasonable" amount has been administered but the hypotension has not resolved, additional fluids are unlikely to provide benefit and may be harmful. This includes causes of absolute (e.g., hemorrhage) or relative (e.g., obstruction or vasodilation) hypovolemia and typically not primary causes of cardiac dysfunction.…”

Choque circulatório em equinos

“…A própria definição do choque circulatório, como uma redução crítica na perfusão tecidual por anormalidade do sistema circulatório, já se transforma em instrumento operacional para elaboração do seu tratamento, não existindo nenhum agente isolado capaz de revertê-lo (MARSON et al, 1998;DRIESSEN;BRAINARD, 2006). Dessa forma, o tratamento do choque circulatório é meramente de suporte.…”

“…As soluções cristalóides contêm um ânion tamponante, seja o acetato ou o lactato. Aparentemente, as soluções contendo acetato são mais adequadas para o restabelecimento da volemia nos estados de choque, pois a capacidade do organismo metabolizar lactato pode estar diminuída nos estados de choque, independente da causa (HJELMQVIST, 2000;DRIESSEN;BRAINARD, 2006). O volume de fluido a ser administrado é estimado com base no déficit para reposição, requerimentos de manutenção e perdas futuras antecipadas.…”

“…Como a salina hipertônica é um potente expansor plasmático, ela deve ser administrada com cuidado. Rápidas velocidades de infusão podem causar hipertensão, bradicardia e potencialmente agravar o estado de choque circulatório (DRIESSEN; BRAINARD, 2006). Outras complicações relatadas na literatura incluem elevação da concentração sérica de Na + , Cl -e da osmolalidade, além de diminuição na concentração de HCO 3 -e K + .…”