Hypertonic Sodium Lactate to Alleviate Functional Deficits Following Diffuse Traumatic Brain Injury: An Osmotic or a Lactate-Related Effect?

BACKGROUND: There has been growing interest in the use of hypertonic sodium lactate (HSL) solution following traumatic brain injury (TBI) in humans. However, little is known about the effects of HSL on functional deficits with respect to the hyperosmotic nature of HSL. METHODS: We have compared the effects of HSL solution and isotonic saline solution using sensorimotor and cognitive tests for 14 days post-trauma in animals. Thirty minutes after trauma (impact-acceleration model), anesthetized rats were randomly allocated to receive a 2-h infusion of isotonic saline solution (TBI-saline group) or HSL (TBI-HSL group) (n = 10 rats per group). In another series of experiments using a similar protocol, the effects of equiosmolar doses of HSL and hypertonic saline solution (HSS) were compared in TBI rats (n = 10 rats per group). Blood lactate and ion concentrations were measured during the 2-h infusions. RESULTS: Compared to the TBI-saline group, the TBI-HSL group had a reduced latency to complete the adhesive removal test: 6 s (5-9) (median [25-75th centiles]) versus 13 s (8-17) on day 7, and 5 s (5-9) versus 11 s (8-26) on day 14 (P < 0.05), respectively, and a shorter delay to complete the radial arm maze test on day 7: 99 s (73-134) versus 176 s (127-300), respectively (P < 0.05). However, no differences were found between the TBI-HSL and TBI-HSS groups in neurocognitive tests performance. Compared to the TBI-saline group, the HSL and HSS groups had higher serum osmolality: 318 mOsm/Kg (315-321) and 315 mOsm/Kg (313-316) versus 307 mOsm/Kg (305-309), respectively (P < 0.05), and the HSL group had a higher serum lactate concentration: 6.4 mmol/L (5.3-7.2) versus 1.5 mmol/L (1.1-1.9) and 1.6 mmol/L (1.5-1.7), respectively (P < 0.05). CONCLUSIONS: These results indicate that improvements in cognitive and sensorimotor tests with HSL infusion post-TBI could be related to elevation of serum osmolality, not to exogenous administration of lactate.

Preoperative fibrinogen level and postcardiac surgery morbidity and mortality rates.

Background: High preoperative fibrinogen levels are associated with reduced bleeding rates after cardiac surgery. Fibrinogen is directly involved in inflammatory processes and is a cardiovascular risk factors. Whether high fibrinogen levels before cardiac surgery are a risk factor for mortality or morbidity remains unclear. Aims: This study aimed to examine the association between preoperative fibrinogen levels and mortality and morbidity rates after cardiac surgery. Settings and Design: This is a single-center retrospective study. Material and Methods: Patients (n = 1628) were divided into high (HFGr) and normal (NFGr) fibrinogen level groups, based on the cutoff value of 3.3 g/L, derived from the receiver operating characteristic (ROC) curve analysis. The primary outcome was the 30-day mortality rate. The rates of postoperative complications, including postoperative bleeding and transfusion rates, were examined. Statistical Analysis: Between-group comparisons were performed with the Mann-Whitney U test and Chi-squared test, as suitable. Model discriminative power was examined with the area under the ROC curve. Results: The HFGr and NFGr included 1103 and 525 patients, respectively. Mortality rate was higher in the HFGr than in the NFGr (2.7% vs. 1.1%, P = 0.04). The 12-h bleeding volume (280 mL [195-400] vs. 305 mL [225-435], P = 0.0003) and 24-h bleeding volume values (400 mL [300-550] vs. 450 mL [340-620], P < 0.0001) were lower in the HFGr than in the NFGr. However, the rate of red blood cell transfusion during hospitalization was higher in the HFGr than in the NFGr (21.7% vs. 5.9%, P = 0.0103). Major complications were more frequent in the HFGr than in the NFGr. Conclusion: High fibrinogen levels were associated with reduced postoperative bleeding volume and increased mortality and morbidity rates.