Impact of a bicarbonated saline solution on early resuscitation after major burns

Patient-centred outcomes are under-reported in the critical care burns literature: a systematic review

BACKGROUND

Developments in the care of critically ill patients with severe burns have led to improved hospital survival, but long-term recovery may be impaired. The extent to which patient-centred outcomes are assessed and reported in studies in this population is unclear.

METHODS

We conducted a systematic review to assess the outcomes reported in studies involving critically ill burns patients. Randomised controlled trials (RCTs) and cohort studies on the topics of fluid resuscitation, analgesia, haemodynamic monitoring, ventilation strategies, transfusion targets, enteral nutrition and timing of surgery were included. We assessed the outcomes reported and then classified these according to two suggested core outcome sets.

RESULTS

A comprehensive search returned 6154 studies; 98 papers met inclusion criteria. There were 66 RCTs, 19 clinical studies with concurrent controls and 13 interventional studies without concurrent controls. Outcome reporting was inconsistent across studies. Pain, reported using the visual analogue scale, fluid volume administered and mortality were the only outcomes measured in more than three studies. Sixty-six studies (67%) had surrogate primary outcomes. Follow-up was poor, with median longest follow-up across all studies 5 days (IQR 3-28). When compared to the suggested OMERACT core outcome set, 53% of papers reported on mortality, 28% reported on life impact, 30% reported resource/economic outcomes and 95% reported on pathophysiological manifestations. Burns-specific Falder outcome reporting was globally poor, with only 4.3% of outcomes being reported across the 98 papers.

CONCLUSION

There are deficiencies in the reporting of outcomes in the literature pertaining to the intensive care management of patients with severe burns, both with regard to the consistency of outcomes as well as a lack of focus on patient-centred outcomes. Long-term outcomes are infrequently reported. The development and validation of a core outcome dataset for severe burns would improve the quality of reporting.

Chloride Content of Fluids Used for Large-Volume Resuscitation Is Associated With Reduced Survival

OBJECTIVE

We sought to investigate if the chloride content of fluids used in resuscitation was associated with short- and long-term outcomes.

DESIGN

We identified patients who received large-volume fluid resuscitation, defined as greater than 60 mL/kg over a 24-hour period. Chloride load was determined for each patient based on the chloride ion concentration of the fluids they received during large-volume fluid resuscitation multiplied by the volume of fluids. We compared the development of hyperchloremic acidosis, acute kidney injury, and survival among those with higher and lower chloride loads.

SETTING

University Medical Center.

PATIENTS

Patients admitted to ICUs from 2000 to 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 4,710 patients receiving large-volume fluid resuscitation, hyperchloremic acidosis was documented in 523 (11%). Crude rates of hyperchloremic acidosis, acute kidney injury, and hospital mortality all increased significantly as chloride load increased (p < 0.001). However, chloride load was no longer associated with hyperchloremic acidosis or acute kidney injury after controlling for total fluids, age, and baseline severity. Conversely, each 100 mEq increase in chloride load was associated with a 5.5% increase in the hazard of death even after controlling for total fluid volume, age, and severity (p = 0.0015) over 1 year.

CONCLUSIONS

Chloride load is associated with significant adverse effects on survival out to 1 year even after controlling for total fluid load, age, and baseline severity of illness. However, the relationship between chloride load and development of hyperchloremic acidosis or acute kidney injury is less clear, and further research is needed to elucidate the mechanisms underlying the adverse effects of chloride load on survival.

Meta-analysis of high- versus low-chloride content in perioperative and critical care fluid resuscitation

Background

The objective of this systematic review and meta-analysis was to assess the relationship between the chloride content of intravenous resuscitation fluids and patient outcomes in the perioperative or intensive care setting.

Methods

Systematic searches were performed of PubMed/MEDLINE, Embase and Cochrane Library (CENTRAL) databases in accordance with PRISMA guidelines. Randomized clinical trials, controlled clinical trials and observational studies were included if they compared outcomes in acutely ill or surgical patients receiving either high-chloride (ion concentration greater than 111 mmol/l up to and including 154 mmol/l) or lower-chloride (concentration 111 mmol/l or less) crystalloids for resuscitation. Endpoints examined were mortality, measures of kidney function, serum chloride, hyperchloraemia/metabolic acidosis, blood transfusion volume, mechanical ventilation time, and length of hospital and intensive care unit stay. Risk ratios (RRs), mean differences (MDs) or standardized mean differences (SMDs) and confidence intervals were calculated using fixed-effect modelling.

Results

The search identified 21 studies involving 6253 patients. High-chloride fluids did not affect mortality but were associated with a significantly higher risk of acute kidney injury (RR 1·64, 95 per cent c.i. 1·27 to 2·13; P < 0·001) and hyperchloraemia/metabolic acidosis (RR 2·87, 1·95 to 4·21; P < 0·001). High-chloride fluids were also associated with greater serum chloride (MD 3·70 (95 per cent c.i. 3·36 to 4·04) mmol/l; P < 0·001), blood transfusion volume (SMD 0·35, 0·07 to 0·63; P = 0·014) and mechanical ventilation time (SMD 0·15, 0·08 to 0·23; P < 0·001). Sensitivity analyses excluding heavily weighted studies resulted in non-statistically significant effects for acute kidney injury and mechanical ventilation time.

Conclusion

A weak but significant association between higher chloride content fluids and unfavourable outcomes was found, but mortality was unaffected by chloride content.

Association between intravenous chloride load during resuscitation and in-hospital mortality among patients with SIRS

PURPOSE

Recent data suggest that both elevated serum chloride levels and volume overload may be harmful during fluid resuscitation. The purpose of this study was to examine the relationship between the intravenous chloride load and in-hospital mortality among patients with systemic inflammatory response syndrome (SIRS), with and without adjustment for the crystalloid volume administered.

METHODS

We conducted a retrospective analysis of 109,836 patients ≥ 18 years old that met criteria for SIRS and received fluid resuscitation with crystalloids. We examined the association between changes in serum chloride concentration, the administered chloride load and fluid volume, and the 'volume-adjusted chloride load' and in-hospital mortality.

RESULTS

In general, increases in the serum chloride concentration were associated with increased mortality. Mortality was lowest (3.7%) among patients with minimal increases in serum chloride concentration (0-10 mmol/L) and when the total administered chloride load was low (3.5% among patients receiving 100-200 mmol; P < 0.05 versus patients receiving ≥ 500 mmol). After controlling for crystalloid fluid volume, mortality was lowest (2.6%) when the volume-adjusted chloride load was 105-115 mmol/L. With adjustment for severity of illness, the odds of mortality increased (1.094, 95% CI 1.062, 1.127) with increasing volume-adjusted chloride load (≥ 105 mmol/L).

CONCLUSIONS

Among patients with SIRS, a fluid resuscitation strategy employing lower chloride loads was associated with lower in-hospital mortality. This association was independent of the total fluid volume administered and remained significant after adjustment for severity of illness, supporting the hypothesis that crystalloids with lower chloride content may be preferable for managing patients with SIRS.

Burn resuscitation

Current guidelines outlining the resuscitation of severely burned patients, in the United States, were developed over 30 years ago. Unfortunately, clinical burn resuscitation has not advanced significantly since that time despite ongoing research efforts. Many formulas exist and have been developed with the intention of providing appropriate, more precise fluid resuscitation with decreased morbidity as compared to the current standards, such as the Parkland and modified Brooke formulas. The aim of this review was to outline the evolution of burn resuscitation, while closely analyzing current worldwide guidelines, adjuncts to resuscitation, as well as addressing future goals.

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.

The effects of saline or albumin resuscitation on acid-base status and serum electrolytes*

OBJECTIVE

To test whether fluid resuscitation with normal saline or 4% albumin is associated with differential changes in acid-base status and serum electrolytes.

DESIGN

Nested cohort study.

SETTING

Three general intensive care units.

PATIENTS

Six hundred and ninety-one critically ill patients.

INTERVENTIONS

Randomization of patients to receive blinded solutions of either 4% human albumin or normal saline for fluid resuscitation.

MEASUREMENTS AND MAIN RESULTS

Albumin was given to 339 patients and saline to 352. At baseline, both groups had a similar serum bicarbonate, albumin, and base excess levels. After randomization, bicarbonate and base excess increased significantly and similarly over time (p < .0001). On multivariate analysis, fluid resuscitation with albumin predicted a smaller increase in pH (p = .0051), bicarbonate (p = .034), and base excess (p = .015). The amount of fluid was an independent predictor of pH (p < .0001), serum chloride (p < .0001), calcium (p = .0001), bicarbonate (p = .0002), and base excess (p < .0001) on the first day of treatment. In patients who received >3 L of fluids in the first 24 hrs, albumin administration was associated with a significantly greater increase in serum chloride (p = .0026). Acute Physiology and Chronic Health Evaluation II score and the presence of sepsis also independently predicted changes in several electrolytes and acid-base variables.

CONCLUSIONS

When comparing albumin and saline, the choice and amount of resuscitation fluid are independent predictors of acid-base status and serum electrolytes. When large volumes are given, albumin administration leads to a higher chloride concentration. However, overall differences between the types of fluid are minor, whereas the volume of fluid administered is a much stronger predictor of such changes, which are also influenced by illness severity and the passage of time.

Resuscitation, anaesthesia and analgesia of the burned patient

Burns resuscitation has evolved over the past few decades towards more evidence-based management. It has been shown that patients with major burns (i.e. involving more than 30% of the body surface) benefit from invasive monitoring, and physiological variable targeted resuscitation using vasoactive agents for cardiovascular support. The invasive approach results in a reduction of mortality rates. Since the introduction of the Parkland formula in 1968, there has been a trend towards the administration of fluid resuscitation far in excess of the volume predicted with this formula. This has led to an increase in complication rates, with more pulmonary oedema, and the appearance of abdominal compartment syndrome. Hypertonic saline solutions, whether with dextran or not, have shown no advantage over the classic Ringer's lactate solution. The colloid controversy has reached burns resuscitation, with the demonstration that the liberal use of albumin is associated with higher mortality rates. Fresh frozen plasma should only be used for specific coagulation disorders. On the other hand, artificial colloids, particularly gelatine, remain a useful tool in patients with major burns and haemodynamic instability, particularly, and can be given as early as 6 h after injury. Considering the actual evidence, using inotropes and vasopressors to reach supranormal haemodynamic endpoints seems preferable to delivering unrestricted amounts of fluid.