Balanced Fluid Versus Saline-Based Fluid in Post-operative Severe Traumatic Brain Injury Patients: Acid Base and Electrolytes Assessment

Background: Normal saline (NS) is a common fluid of choice in neurosurgery and neurointensive care unit (ICU), but it does not contain other electrolytes and has the potential to cause hyperchloremic metabolic acidosis with prolonged infusion. These problems may be reduced with the availability of balanced fluid (BF), which becomes a more physiological isotonic solution with the presence of complete electrolyte content. This study aimed to compare the changes in electrolytes and acid–base between NS and BF (Sterofundin® ISO) therapy for post-operative severe traumatic brain injury (TBI) patients in neuro-ICU. Methods: Sixty-six severe TBI patients who required emergency craniotomy or craniectomy and were planned for post-operative ventilation were randomised into NS (n = 33) and BF therapy groups (n = 33). The calculation of maintenance fluid given was based on the Holliday-Segar method. The electrolytes and acid–base parameters were assessed at an 8 h interval for 24 h. The data were analysed using repeated measures ANOVA. Results: The NS group showed a significant lower base excess (-3.20 versus -1.35, P = 0.049), lower bicarbonate level (22.03 versus 23.48 mmol/L, P = 0.031), and more hyperchloremia (115.12 versus 111.74 mmol/L, P < 0.001) and hypokalemia (3.36 versus 3.70 mmol/L, P < 0.001) than the BF group at 24 h of therapy. The BF group showed a significantly higher level of calcium (1.97 versus 1.79 mmol/L, P = 0.003) and magnesium (0.94 versus 0.80 mmol/L, P < 0.001) than the NS group at 24 h of fluid therapy. No significant differences were found in pH, pCO2, lactate, and sodium level. Conclusion: BF therapy showed better effects in maintaining higher electrolyte parameters and reducing the trend toward hyperchloremic metabolic acidosis than the NS therapy during prolonged fluid therapy for postoperative TBI patients.

Acidosis hiperclorémica: mito y realidad / Hyperchloremic acidosis

La acidosis metabólica es una alteración ácido-base frecuentemente observada en pacientes críticos. Aunque en situaciones extremas este desorden en sí mismo es amenazante para la vida, la presencia de una acidosis metabólica leve no siempre es nociva y puede ser un reflejo de la adaptación fisiológica del organismo a la injuria aguda. Diferentes autores han documentado el desarrollo de acidosis metabólica hiperclorémica asociada al aporte de grandes cantidades de solución salina 0,9 por ciento. Algunos consideran que se trata de una condición benigna y autolimitada, mientras otros sostienen que la acidosis hiperclorémica puede deteriorar la perfusión renal y esplácnica, sin embargo su relevancia clínica real es aún incierta. En un afán de evitar la aparición de acidosis hiperclorémica y sus potenciales efectos adversos, se han desarrollado cristaloides y coloides en formulaciones modificadas para que se asemejen más a la composición del plasma. En este artículo de revisión analizaremo slos mecanismos de producción de la acidosis metabólica hiperclorémica en base al abordaje físico-químico de Stewart; la evidencia existente sobre el impacto de este trastorno sobre las variables de desenlace de los pacientes críticos, y el rol clínico de las nuevas “soluciones balanceadas”.

Metabolic acidosis is an acid-base alteration frequently observed in critically ill patients. Even in extreme situations this disorder in itself is life threatening, the presence of a mild metabolic acidosis is not always harmful and may be the result of physiological adaptation of the organism to acute injury. Several authors have documented the development of hyperchloremic metabolic acidosis associated with the infusion of large amounts of 0.9 percent normal saline. Some consider this to be a benign and transient, while others argue that hyperchloremic acidosis can impair renal and splanchnic perfusion, but her real clinical relevance remains uncertain. In an effort to prevent the development of hyperchloremic acidosis and its potential adverse effects have been development formulations of crystalloid and colloid modified to more closely resemble the composition of the plasma. In this review article will discuss the mechanism of production of hyperchloremic metabolic acidosis by the physicochemical approach Stewart, the existing evidence on the impact of this disorder on the outcome variables in critically ill patients, and clinical role of new “balanced solutions”.