Limited resuscitation with hypertonic saline, hypertonic sodium acetate, and lactated Ringer's solutions in a model of uncontrolled hemorrhage from a vascular injury

Influence of acetate containing fluid versus lactate containing fluid on acid-base status, electrolyte level, and blood lactate level in dehydrated dogs

BACKGROUND AND AIM

Acetate or lactate buffered, balanced isotonic rehydration fluids are commonly used for fluid therapy in dogs and may influence acid-base and electrolyte status. This study aimed to assess acid-base status, electrolyte levels, and lactate levels in dehydrated dogs after receiving acetate or lactate-containing intravenous rehydration fluids.

MATERIALS AND METHODS

In this prospective, randomized study, 90 dehydrated dogs were included and randomized to receive acetate [Sterofundin® ISO B. Braun Vet Care (STERO), Germany) or lactate (Ringer-Lactat-Lösung nach Hartmann B. Braun Vet Care (RL), Germany] containing intravenous fluids for rehydration. The exclusion criteria were as follows: Age <6 months, liver failure, congestive heart failure, and extreme electrolyte deviation. Physical examination, venous blood gas, and lactate levels were analyzed before and after rehydration. The two groups were compared using t-test and Chi-square test. The significance level was set at p≤0.05.

RESULTS

Post-rehydration heart rate decreased in the STERO group (p<0.001) but not in the RL group (p=0.090). Lactate levels decreased in both groups STERO (p<0.001) and in group RL (p=0.014). Sodium and chloride levels increased during rehydration in group STERO (p<0.001; p<0.001) and group RL (p=0.002; p<0.001). There was a larger decrease in lactate levels in group STERO compared to group RL (p=0.047).

CONCLUSION

Both solutions led to a mild increase in sodium and chloride levels and decreased lactate levels. The acetate-containing solution had an inferior effect on the decrease in lactate level.

Fluid management in patients undergoing cardiac surgery: effects of an acetate- versus lactate-buffered balanced infusion solution on hemodynamic stability (HEMACETAT)

BACKGROUND

Recent evidence suggests that acetate-buffered infusions result in better hemodynamic stabilization than 0.9% saline in patients undergoing major surgery. The choice of buffer in balanced crystalloid solutions may modify their hemodynamic effects. We therefore compared the inopressor requirements of Ringer's acetate and lactate for perioperative fluid management in patients undergoing cardiac surgery.

METHODS

Using a randomized controlled double-blind design, we compared Ringer's acetate (RA) to Ringer's lactate (RL) with respect to the average rate of inopressor administered until postoperative hemodynamic stabilization was achieved. Secondary outcomes were the cumulative dose of inopressors, the duration of inopressor administration, the total fluid volume administered, and the changes in acid-base homeostasis. Patients undergoing elective valvular cardiac surgery were included. Patients with severe cardiac, renal, or liver disease were excluded from the study.

RESULTS

Seventy-five patients were randomly allocated to the RA arm, 73 to the RL. The hemodynamic profiles were comparable between the groups. The groups did not differ with respect to the average rate of inopressors (RA 2.1 mcg/kg/h, IQR 0.5-8.1 vs. RL 1.7 mcg/kg/h, IQR 0.7-8.2, p = 0.989). Cumulative doses of inopressors and time on individual and combined inopressors did not differ between the groups. No differences were found in acid-base parameters and their evolution over time.

CONCLUSION

In this study, hemodynamic profiles of patients receiving Ringer's lactate and Ringer's acetate were comparable, and the evolution of acid-base parameters was similar. These study findings should be evaluated in larger, multi-center studies.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02895659 . Registered 16 September 2016.

Effects of volume and composition of the resuscitative fluids in the treatment of hemorrhagic shock

Objectives:

To evaluate the effectiveness of normal saline, hypertonic saline, and Ringer's lactate solution followed by blood infusion in ameliorating the physiological, biochemical, and organ functions following hemorrhagic shock (HS) in rats.

Materials and Methods:

Anesthetized, male Sprague-Dawley rats underwent computer-controlled HS, and were randomly divided into five groups consisting of (1) sham, (2) HS without resuscitation, (3) resuscitation with normal saline, (4) resuscitation with hypertonic saline, and (5) resuscitation with Ringer's lactate solution. All resuscitated animals were infused with subsequent infusion of shed blood. Animals were continuously monitored for physiological, hemodynamic, biochemical parameters, and organ dysfunctions.

Results:

Non-resuscitated animals were unable to survive due to hypotension, poor oxygen metabolism, and lactic acidosis. Although these HS related parameters were corrected by all the fluids used in this study, additional blood infusion was more effective than fluid resuscitation alone. Also, hypertonic saline was more effective than Ringer's lactate solution, and normal saline was the least effective in preserving the liver and kidney functions and muscle damage.

Conclusions:

All crystalloid fluids were significantly more effective in reversing the HS outcome when used with blood infusion, but hypertonic salinewith blood was more effective in preventing the organ damage than Lactated Ringers solutions or normal saline in the treatment of HS.

Hypertonic sodium pyruvate solution is more effective than Ringer's ethyl pyruvate in the treatment of hemorrhagic shock

Hypertonic sodium pyruvate (HSP), as well as ethyl pyruvate solutions, has been proposed as resuscitative fluids in the treatment of hemorrhagic shock (HS) because of their anti-inflammatory and antioxidant properties. The effectiveness of one pyruvate preparation over the other in the treatment of HS has not been evaluated. The authors aimed to compare two pyruvate solutions for resuscitation and their mechanisms of action in rats during HS. The effects of infusion of low-volume HSP were compared against high-volume Ringer's ethyl pyruvate on hemodynamic parameters, inflammatory cascade, and regulation of stress and apoptosis-related proteins in the liver. Sprague-Dawley rats were either treated as sham animals or subjected to computer-controlled arterial hemorrhage (40 mmHg) for 60 min followed by resuscitation with isotonic sodium chloride solution, hypertonic saline, Ringer's lactate solution, Ringer's ethyl pyruvate, or HSP for 60 min. Animals were continuously monitored for hemodynamic and biochemical parameters in blood. At the end of the experiment, animals were killed, and liver samples were taken for the evaluation of inflammatory and anti-inflammatory markers and mediators of oxidative stress, liver injury, and expression of apoptotic signaling proteins. In comparison with Ringer's ethyl pyruvate, HSP administration after hemorrhage reduced liver injury, which was associated with increased levels of serum and tissue inflammatory cytokines, inflammatory mediators such as NOS and cyclooxygenase 2, lipid peroxidation, and higher hepatocellular adenosine triphosphate. Cellular apoptotic events related to the activation of caspase-3 and poly(ADP-ribose)polymerase cleavage were also decreased by sodium pyruvate. Resuscitation with small-volume HSP offers significant protection against inflammatory and oxidative stress and in preventing liver injury compared with large-volume Ringer's ethyl pyruvate.

Enhancement of cerebral blood flow using systemic hypertonic saline therapy improves outcome in patients with poor-grade spontaneous subarachnoid hemorrhage

OBJECT

Systemic administration of 23.5% hypertonic saline enhances cerebral blood flow (CBF) in patients with poor-grade spontaneous subarachnoid hemorrhage (SAH). Whether the increment of change in CBF correlates with changes in autoregulation of CBF or outcome at discharge remains unknown.

METHODS

Thirty-five patients with poor-grade spontaneous SAH received 2 ml/kg 23.5% hypertonic saline intravenously, and they underwent bedside transcranial Doppler (TCD) ultrasonography and intracranial pressure (ICP) monitoring. Seventeen of them underwent Xe-enhanced computed tomography (CT) scanning for measuring CBF. Outcome was assessed using the modified Rankin Scale (mRS) at discharge from the hospital. The data were analyzed using repeated-measurement analysis of variance and Dunnett correction. A comparison was made between patients with favorable and unfavorable outcomes using multivariate logistic regression.

RESULTS

The authors observed a maximum increase in blood pressure by 10.3% (p < 0.05) and cerebral perfusion pressure (CPP) by 21.2% (p < 0.01) at 30 minutes, followed by a maximum decrease in ICP by 93.1% (p < 0.01) at 60 minutes. Changes in ICP and CPP persisted for longer than 180 and 90 minutes, respectively. The results of TCD ultrasonography showed that the baseline autoregulation was impaired on the ipsilateral side of ruptured aneurysm, and increments in flow velocities were higher and lasted longer on the contralateral side (48.75% compared with 31.96% [p = 0.045] and 180 minutes compared with 90 minutes [p < 0.05], respectively). The autoregulation was briefly impaired on the contralateral side during the infusion. A dose-dependent effect of CBF increments on favorable outcome was seen on Xe-CT scans (mRS Score 1-3, odds ratio 1.27 per 1 ml/100 g tissue x min, p = 0.045).

CONCLUSIONS

Bolus systemic hypertonic saline therapy may be used for reversal of cerebral ischemia to normal perfusion in patients with poor-grade SAH.

Use of Nuclear Magnetic Resonance Spectroscopy to Assess Renal Dysfunction After Hypertonic-Hyperoncotic Resuscitation in Rats

BACKGROUND

The aim of this study was to evaluate the renal tolerance of a hypertonic-hyperoncotic solution (HHS) administration during uncontrolled hemorrhagic shock (UHS).

METHODS

UHS was produced in rats by a preliminary bleed followed by tail amputation. Hydroxyethylstarch (HHS) 200/0.5 6% in NaCl 7.2% was administered to the HHS groups (n = 20) and normal saline (NS) to the NS group (n = 20). Infusion rates were adjusted to prevent mean arterial pressure (MAP) from falling either below 40 mm Hg in the HHS40 (n = 10) and NS40 groups (n = 10), or below 80 mm Hg in the HHS80 (n = 10) and NS80 groups (n = 10). Data obtained were compared with a sham group and a no resuscitation (NR) group. Nephrotoxicity was evaluated by nuclear magnetic resonance analysis in urine samples.

RESULTS

Survival was 60% in the NS40 group and 40% in the NS80 group, 70% in the HHS40 group, and 60% in the HHS80 group (p = not significant). Within and between target groups of 40 mm Hg MAP and 80 mm Hg MAP, there was no significant difference in survival. The mean values of renal metabolites to creatinine (ct) ratios were not significantly different among the six groups. Principal component analysis showed that the HHS80 group was characterized by an increase in allantoin/ct and urea/ct ratios demonstrating acute renal dysfunction and failure of nitrogen metabolism.

CONCLUSION

In prolonged UHS, an infusion of HHS may not increase the rate of survival. HHS infusion in normotensive resuscitation appears to be associated with renal toxicity.

Timing of Fluid Resuscitation Shapes the Hemodynamic Response to Uncontrolled Hemorrhage: Analysis Using Dynamic Modeling

BACKGROUND

Timing of fluid resuscitation with respect to intrinsic hemostasis is an unexplored aspect of uncontrolled hemorrhage, because most animal models do not allow direct monitoring of blood loss. The aim of this study was to define how timing of crystalloid administration affects the bleeding patient's hemodynamic response to fluids, using a computer model of blood volume changes during uncontrolled hemorrhage.

METHODS

A multi-compartment lumped-parameter deterministic model of intravascular volume changes in a bleeding adult patient was developed and implemented. The model incorporates empirical mathematical descriptions of intrinsic hemostasis and rebleeding.

RESULTS

The predicted hemodynamic response to uncontrolled hemorrhage closely corresponds to that seen in animal studies. A 2-L crystalloid bolus given during ongoing hemorrhage increases blood loss by 4 to 29%, an effect that is inversely related to the initial bleeding rate. A similar bolus given after intrinsic hemostasis may trigger rebleeding if given when the hemostatic clot is mechanically vulnerable. This period of clot vulnerability (ranging from 0-34 minutes) changes with both the initial bleeding rate and the rate of fluid administration.

CONCLUSIONS

The timing of crystalloid administration with respect to intrinsic hemostasis shapes the bleeding patient's hemodynamic response. An early bolus delays hemostasis and increases blood loss, while a late bolus may trigger rebleeding. These observations provide valuable insight into the hemodynamic response to fluid resuscitation.

DO PLASMA SUBSTITUTES HAVE ADDITIONAL PROPERTIES BEYOND CORRECTING VOLUME DEFICITS?

The best strategy for volume therapy has been the focus of debate and there are still no unique accepted guidelines. There is increasing evidence that some plasma substitutes possess additional effects on organ perfusion, microcirculation, tissue oxygenation, inflammation, endothelial activation, capillary leakage, and tissue edema that are beyond their volume replacing properties. Whether the different plasma substitutes differ with regard this additional effects was reviewed. The additional effects of plasma substitutes have mostly been studied experimentally or in animals, much less results are available in humans. The results are not uniform ranging from beneficial to even detrimental effects of a certain volume replacement strategy. Some important results from the literature are not reflected in the actual recommendations for treating volume deficits in the critically ill: although crystalloids have been shown to have considerable negative effects on microcirculation, organ perfusion, tissue oxygenation, and endothelial integrity, they are still often recommended as first choice volume replacement strategy. In several experimental studies hypertonic solutions have been shown to have various beneficial effects, they have not been, however, translated into humans. In future, the choice of the ideal volume replacement regimen should not only be focused on its volume restoring properties, but additional effects (e.g. on organ perfusion on, tissue oxygenation, inflammation, endothelial activation, capillary leakage) should also be taken into account when treating hypovolemia in the critically ill.

Titrated hypertonic/hyperoncotic solution for hypotensive fluid resuscitation during uncontrolled hemorrhagic shock in rats

BACKGROUND

In volume- or pressure-controlled hemorrhagic shock (HS) a bolus intravenous infusion of hypertonic/hyperoncotic solution (HHS) proved beneficial compared to isotonic crystalloid solutions. During uncontrolled HS in animals, however, HHS by bolus increased blood pressure unpredictably, and increased blood loss and mortality. We hypothesized that a titrated i.v. infusion of HHS, compared to titrated lactated Ringer's solution (LR), for hypotensive fluid resuscitation during uncontrolled HS reduces fluid requirement, does not increase blood loss, and improves survival.

METHODS

We used our three-phased uncontrolled HS outcome model in rats. HS phase I began with blood withdrawal of 3 ml/100g over 15 min, followed by tail amputation. Then, hydroxyethyl starch 10% in NaCl 7.2% was given i.v. to the HHS group (n=10) and LR to the control group (n=10), both titrated to prevent mean arterial pressure (MAP) from falling below 40 mmHg during HS time 20-90 min. At HS 90 min, resuscitation phase II of 180 min began with hemostasis, return of all the blood initially shed, plus fluids i.v. as needed to maintain normotension (MAP>or=70 mmHg). Liver dysoxia was monitored as increase in liver surface pCO2 during phases I and II. Observation phase III was to 72 h.

RESULTS

During HS, preventing a decrease in MAP below 40 mmHg required HHS 4.9+/-0.6 ml/kg (all data mean+/-S.E.M.), compared to LR 62.2+/-16.6 ml/kg (P<0.001), with no group difference in MAP. Uncontrolled blood loss during HS from the tail stump was 13.3+/-1.9 ml/kg with HHS infusion, versus 12.6+/-2.5 ml/kg with LR infusion (P=0.73). Serum sodium concentrations were moderately elevated at the end of HS in the HHS group (149+/-3 mmol/l) versus the LR group (139+/-1 mmol/l) (P=0.001), and remained elevated throughout. Liver pCO2 increased during HS in both groups equally (P<0.001 versus baseline), and tended to return to baseline levels at the end of HS. Blood gas and lactate values throughout did not differ between groups. During HS, 2 of 10 rats in the HHS group versus 0 of 10 in the LR group died (P=0.47). There was no difference between HHS and LR groups in survival rates to 72 h (3 of 10 in the HHS group versus 2 of 10 in the LR group) (P=1.0). Survival times, by life table analysis, were not different (P=0.75).

CONCLUSION

In prolonged uncontrolled HS, a titrated i.v. infusion of HHS can maintain controlled hypotension with only one-tenth of the volume of LR required, without increasing blood loss. This titrated HHS strategy may not increase the chance of long-term survival.

A Hemoglobin Based Oxygen Carrier, Bovine Polymerized Hemoglobin (HBOC-201) versus Hetastarch (HEX) in an Uncontrolled Liver Injury Hemorrhagic Shock Swine Model with Delayed Evacuation

BACKGROUND

As HBOC-201 improves outcome in animals with hemorrhagic shock (HS), we compared HBOC-201 and HEX (used by U.S. military special operations forces) in a swine model of delayed evacuation and uncontrolled HS.

METHODS

Twenty-four Yucatan pigs underwent a grade III liver injury and were resuscitated with HBOC-201, HEX, or no fluid (NON). Additional infusions were given for hypotension or tachycardia. After 4 hours, the liver was repaired; IV fluids and blood transfusions were administered. Pigs were monitored for 72 hours.

RESULTS

Survival was 7/8, 1/8, and 1/8 in HBOC-201-, HEX-, and NON-resuscitated pigs, respectively. Compared with HEX, HBOC-201 pigs had higher systemic and pulmonary artery pressures and had comparable cardiac outputs, but were less tachycardic. Transcutaneous tissue oxygenation was restored more rapidly in HBOC-201 pigs, there was a trend to lower lactic acid, and base deficit was less. HBOC-201 pigs had lower fluid requirements, higher urine output, and lower blood loss than HEX pigs.

CONCLUSIONS

Despite evidence of vasoactivity, HBOC-201 more effectively stabilized tissue oxygenation, reversed anaerobic metabolism, decreased bleeding, and increased survival in comparison with HEX. If confirmed in clinical trials, these data suggest that for the resuscitation of combat casualties with delayed evacuation and uncontrolled HS due to solid organ injury, HBOC-201 is a superior low-volume resuscitative fluid.

The Early Systemic and Gastrointestinal Oxygenation Effects of Hemorrhagic Shock Resuscitation with Hypertonic Saline and Hypertonic Saline 6% Dextran-70: A Comparative Study in Dogs

The smaller volemic state from hypertonic (7.5%) saline (HS) solution administration in hemorrhagic shock can determine lesser systemic oxygen delivery and tissue oxygenation than conventional plasma expanders. In a model of hemorrhagic shock in dogs, we studied the systemic and gastrointestinal oxygenation effects of HS and hyperoncotic (6%) dextran-70 in combination with HS (HSD) solutions in comparison with lactated Ringer's (LR) and (6%) hydroxyethyl starch (HES) solutions. Forty-eight mongrel dogs were anesthetized, mechanically ventilated, and subjected to splenectomy. A gastric air tonometer was placed in the stomach for intramucosal gastric CO(2) (Pgco(2)) determination and for the calculation of intramucosal pH (pHi): The dogs were hemorrhaged (42% of blood volume) to hold mean arterial blood pressure at 40-50 mm Hg over 30 min and were then resuscitated with LR (n = 12) in a 3:1 relation to removed blood volume; HS (n = 12), 6 mL/kg; HSD (n = 12), 6 mL/kg; and HES (mean molecular weight, 200 kDa; degree of substitution, 0.5) (n = 12) in a 1:1 relation to the removed blood volume. Hemodynamic, systemic, and gastric oxygenation variables were measured at baseline, after 30 min of hemorrhage, and 5, 60, and 120 min after intravascular fluid resuscitation. After fluid resuscitation, HS showed significantly lower arterial pH and mixed venous Po(2) and higher systemic oxygen uptake index and systemic oxygenation extraction than LR and HES (P < 0.05), whereas HSD showed significantly lower arterial pH than LR and HES (P < 0.05). Only HS and HSD did not return arterial pH and pHi to control levels (P < 0.05). In conclusion, all solutions improved systemic and gastrointestinal oxygenation after hemorrhagic shock in dogs. However, the HS solution showed the worst response in comparison to LR and HES solutions in relation to systemic oxygenation, whereas HSD showed intermediate values. HS and HSD solutions did not return regional oxygenation to control values.

Haemodynamic and volumetric monitoring during haemorrhagic shock in swine

Various studies have been performed concerning haemodynamics in the shock state. The aim of this study was to examine if a haemodynamic approach based on volumetric indices can offer a new method of evaluation. Volumetric measurements of ventricular filling and cardiac function were compared with classical haemodynamic variables during induced haemorrhagic shock in swine. Twelve hybrid swine were anaesthetized and underwent arteriectomy to induce haemorrhagic shock. Blood was collected in ACD treated bags and reinfused via the same vein after a shock period of 90 min. Haemodynamic and volume measurements were evaluated. Seven swine survived to complete the protocol and reached the final experimental time (90 min after reinfusion), while the remaining five died 1 h after reinfusion. Concerning the haemodynamics, afterload changes characterized the haemorrhagic shock period, while blood volume distribution dictated ventricular filling and ventricular kinetics during the post-reinfusion period. Systemic vascular resistance was different in the two groups. This study suggests that blood volumetric evaluations can offer better comparative data than pulmonary catheterisation for a precise assessment of cardiac output. Preload values have turned out to be of greater relevance than traditional pressure variables.

Resuscitation from traumatic shock

Shock is the body's response to decreased cellular perfusion. It can begin with hemorrhage, mechanical obstruction of the circulation, cardiac dysfunction, central nervous system injury, or sepsis. Once triggered, shock is perpetuated by the release of toxic compounds from ischemic cells. The treatment of shock consists of the removal or correction of the triggering pathology, followed by resuscitation back to the normal state. Clinical research in shock resuscitation in the past year has focused on recognizing the presence of shock in patients at risk, particularly those with normal vital signs but ongoing, occult hypoperfusion. In the laboratory, the emphasis has been on minimizing the initial hemorrhagic insult, minimizing the release of toxins from ischemic cells, and blocking the response to the toxins that are released.

End-points of resuscitation how much is enough?

Fluid resuscitation after traumatic hemorrhage has historically been instituted as soon after injury as possible. Patients suffering from hemorrhagic shock may receive several liters of crystalloid, in addition to colloid solutions, in an attempt to normalize blood pressure, heart rate, urine output, and mental status, which are the traditional end-points of resuscitation. Current theory and recent investigations have questioned this dogma. Resuscitation goals may be different between when the patient is actively hemorrhaging, and once bleeding has been controlled. Newer markers of tissue and organ system perfusion may allow a more precise determination of adequate resuscitation.