Agreement of measured and calculated serum osmolality during the infusion of mannitol or hypertonic saline in patients after craniotomy: a prospective, double-blinded, randomised controlled trial

Comparison of 4.54% hypertonic saline and 20% mannitol for brain relaxation during auditory brainstem implantation in pediatric patients: a single-center retrospective observational cohort study

BACKGROUND

Mannitol is frequently utilized to achieve intracranial brain relaxation during the retrosigmoid approach for auditory brainstem implantation (ABI). Hypertonic saline (HS) is an alternative for reducing intracranial pressure; however, its application during ABI surgery remains under-investigated. We aimed to compare the efficacy and safety between HS and mannitol for maintaining brain relaxation.

METHODS

This single-center retrospective cohort study included pediatric patients undergoing ABI surgery from September 2020 to January 2022 who received only 4.54% HS or 20% mannitol for brain relaxation. The analysis involved initial doses, subsequent doses, and dosing intervals of the two hyperosmolar solutions, as well as the time elapsed from meningeal opening to the first ABI electrode placement attempt. Additionally, the analysis encompassed electrolyte testing, hemodynamic variables, urine output, blood transfusion, second surgeries, adverse events, intensive care unit length of stay, and 30-day mortality.

RESULTS

We analyzed 68 consecutive pediatric patients; 26 and 42 in the HS and mannitol groups, respectively. The HS group exhibited a reduced rate of supplementary use (7.7% vs. 31%) and lower total urine volume. Perioperative outcomes, mortality, and length of intensive care unit stay did not exhibit significant between-group differences, despite transient increases in blood sodium and chloride observed within 2 h after HS infusion.

CONCLUSIONS

In pediatric ABI surgery, as an osmotherapy for cerebral relaxation, 4.54% HS demonstrated a lower likelihood of necessitating additional supplementation than 20% mannitol. Furthermore, the diuretic effect of HS was weak and the increase in electrolyte levels during surgery was temporary and slight.

Hypertonic Saline Solution Versus Mannitol for Brain Relaxation During Craniotomies: A Systematic Review and Updated Meta-Analysis

BACKGROUND AND OBJECTIVES

The preferred osmotic agent used for brain relaxation during craniotomies remains unclear, either mannitol (MAN) or hypertonic saline (HTS). Hence, we sought to compare these solutions in this population.

METHODS

MEDLINE, Embase, and Cochrane databases were systematically searched until August 02, 2023. Data were examined using the Mantel-Haenszel method and 95% CIs. Heterogeneity was assessed using I2 statistics. Meta-regression analysis was conducted to evaluate a possible link between Brain Relaxation Score and tumor volume. R, version 4.2.3, was used for statistical analysis.

RESULTS

A total of 16 randomized controlled trials and 1031 patients were included, of whom 631 (61%) underwent surgery for supratentorial tumor resection. Compared with MAN, HTS achieved better rates of brain relaxation (80% vs 71%; odds ratio [OR] 1.68; 95% CI 1.22-2.33; P = .001; I2 = 0%), which was also demonstrated in the subgroup analysis of patients with supratentorial brain tumor (78% vs 65%; OR 2.02; 95% CI 1.36-2.99; P = .0005; I2 = 0%); a minor number of patients requiring a second dose of osmotic agent (14% vs 28%; OR 0.43; 95% CI 0.27-0.69; P = .0003; I2 = 0%); a lower fluid intake (mean difference -475.9341 mL; 95% CI -818.8952 to -132.9730; P = .007; I2 = 88%); and lower urine output (mean difference -462.0941 mL; 95% CI -585.3020 to -338.8862; P = <.001; I2 = 96%). Hospital length of stay and focal neurological deficits did not reach a statistically significant difference between groups.

CONCLUSION

In this updated meta-analysis, consistent results suggest that HTS is associated with more beneficial outcomes than MAN in patients undergoing craniotomy.

Hypertonic Saline vs. Mannitol in Management of Elevated Intracranial Pressure in Children: A Meta-Analysis

OBJECTIVE

To compare the efficacy and safety of two hyperosmolar agents (hypertonic saline vs. mannitol) used for the reduction of elevated intracranial pressure (ICP) in children.

METHODS

A meta-analysis of randomized controlled trials (RCTs) was conducted and GRADE system (Grading of Recommendations, Assessment, Development and Evaluation) of evidence was applied. Relevant databases were searched till 31st May 2022. Primary outcome was mortality rate.

RESULTS

Of 720 citations retrieved, 4 RCTs were included in the meta-analysis (n = 365, male = 61%). Traumatic and non-traumatic cases of elevated ICP were included. There was no significant difference in the mortality rate between the two groups [relative risk (RR), 1.09; (95% confidence interval (CI), 0.74 to 1.6)]. No significant difference was found for any of the secondary outcomes, except serum osmolality (being significantly higher in mannitol group). Adverse events like shock and dehydration were significantly higher in the mannitol group, and hypernatremia in the hypertonic saline group. The evidence generated for primary outcome was of "low certainty", and for secondary outcomes, it varied from "very-low to moderate certainty".

CONCLUSIONS

There is no significant difference between hypertonic saline and mannitol used for the reduction of elevated ICP in children. The evidence generated for primary outcome (mortality rate) was of "low certainty", and for secondary outcomes, it varied from "very-low to moderate certainty". More data from high-quality RCTs are needed to guide any recommendation.

A teaspoon of sugar and a pinch of salt: Reviewing hyperosmolar therapy

ABSTRACT

The traditional hyperosmolar agents used to treat patients with elevated intracranial pressure are mannitol and hypertonic sodium chloride solution. This article focuses on some of the pros and cons of these treatments for managing cerebral edema.

Retrospective evaluation of the association between hyponatremia and neurological dysfunction in hospitalized foals (2012-2016): 109 cases

OBJECTIVE

Hyponatremia and rapid correction of hyponatremia can lead to neurological abnormalities. The objective of the study was to determine whether plasma sodium concentrations (Na⁺ ) and speed of correction of hyponatremia are significantly associated with neurological abnormalities in foals.

DESIGN

Retrospective cohort study 2012 to 2016.

SETTING

Equine hospital.

ANIMALS

One hundred and nine foals <6 months old with hyponatremia (Na⁺ concentration ≤125 mmol/L).

INTERVENTIONS

Case records were reviewed for any foal with hyponatremia. Clinicopathological findings, presence or absence of neurological signs on the day of the lowest Na⁺ concentration measured and the following 5 days, diagnosis and outcome were recorded, and changes in Na⁺ concentration per hour were calculated for up to 5 subsequent days. Logistic regression was used to assess the association between presence or absence of neurological signs, Na⁺ concentration, other known risk factors for neurological dysfunction in foals, and possible confounders.

MEASUREMENTS AND MAIN RESULTS

In the final multivariable model, only Na⁺ (odds ratio [OR]: 0.86; 95% CI 0.79-0.95; P = 0.002) and BUN concentrations (OR: 1.04; 95% CI: 1.02-1.06; P = 0.001) were significantly associated with neurological signs. Changes in Na⁺ concentrations per hour were not associated with neurological signs on any day after the lowest Na⁺ concentration had been measured (P = 0.18-0.82), and development of new neurological signs following correction of hyponatremia was not reported in any foal.

CONCLUSIONS

Na⁺ concentrations were associated with the development of neurological signs in hyponatremic foals. Increased BUN concentrations might contribute to neurological dysfunction, but further studies are necessary to confirm or refute these findings.

Analyzing the efficacy of frequent sodium checks during hypertonic saline infusion after elective brain tumor surgery

OBJECTIVE

To assess the utility of frequent sodium checks (every 6h) in patients receiving hypertonic saline (HS) after elective brain tumor surgeries.

PATIENTS AND METHODS

A single-institution retrospective review of patients having undergone elective craniotomies for brain tumors and treated with postoperative continuous intravenous infusions of 3% HS was performed. Changes in serum sodium values were analyzed at different time points. The rates of <12.5, 25, and 50cc/h infusions were also examined. Healthcare cost analysis was performed by extrapolating our cohort to the total number of craniotomies performed in the United States.

RESULTS

No significant differences among sodium values checked between 0 to 4, 4-6, 6-8, 8-10, and >10h were observed (P=.64). In addition, no differences in serum sodium values among the rates of <12.5, 25, and 50cc/h were found (P=.30). No patients developed symptoms of acute hypernatremia.

CONCLUSIONS

Serum sodium values did not significantly change more than 10h after infusion of HS. Further studies are needed to determine the optimal frequency of routine sodium checks to increase the quality of care and decrease healthcare costs.

Hypertonic salt solution for peri-operative fluid management

BACKGROUND

Fluid excess may place people undergoing surgery at risk for various complications. Hypertonic salt solution (HS) maintains intravascular volume with less intravenous fluid than isotonic salt (IS) solutions, but may increase serum sodium. This review was published in 2010 and updated in 2016.

OBJECTIVES

To determine the benefits and harms of HS versus IS solutions administered for fluid resuscitation to people undergoing surgery.

SEARCH METHODS

In this updated review we have searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4, 2016); MEDLINE (January 1966 to April 2016); EMBASE (January 1980 to April 2016); LILACS (January 1982 to April 2016) and CINAHL (January 1982 to April 2016) without language restrictions. We conducted the original search on April 30th, 2007, and reran it on April 8th, 2016.

SELECTION CRITERIA

We have included randomized clinical trials (RCTs) comparing HS to IS in people undergoing surgery, irrespective of blinding, language, and publication status.

DATA COLLECTION AND ANALYSIS

Two independent review authors read studies that met our selection criteria. We collected study information and data using a data collection sheet with predefined parameters. We have assessed the impact of HS administration on mortality, organ failure, fluid balance, serum sodium, serum osmolarity, diuresis and physiologic measures of cardiovascular function. We have pooled the data using the mean difference (MD) for continuous outcomes. We evaluated heterogeneity between studies by I² percentage. We consider studies with an I² of 0% to 30% to have no or little heterogeneity, 30% to 60% as having moderate heterogeneity, and more than 60% as having high heterogeneity. In studies with low heterogeneity we have used a fixed-effect model, and a random-effects model for studies with moderate to high heterogeneity.

MAIN RESULTS

We have included 18 studies with 1087 participants of whom 545 received HS compared to 542 who received IS. All participants were over 18 years of age and all trials excluded high-risk patients (ASA IV). All trials assessed haematological parameters peri-operatively and up to three days post-operatively.There were three (< 1%) deaths reported in the IS group and four (< 1%) in the HS group, as assessed at 90 days in one study. There were no reports of serious adverse events. Most participants were in a positive fluid balance postoperatively (4.4 L IS and 2.5 L HS), with the excess significantly less in HS participants (MD -1.92 L, 95% confidence interval (CI) -2.61 to -1.22 L; P < 0.00001). IS participants received a mean volume of 2.4 L and HS participants received 1.49 L, significantly less fluid than IS-treated participants (MD -0.91 L, 95% CI -1.24 to -0.59 L; P < 0.00001). The maximum average serum sodium ranged between 138.5 and 159 in HS groups compared to between 136 and 143 meq/L in the IS groups. The maximum serum sodium was significantly higher in HS participants (MD 7.73, 95% CI 5.84 to 9.62; P < 0.00001), although the level remained within normal limits (136 to 146 meq/L).A high degree of heterogeneity appeared to be related to considerable differences in the dose of HS between studies. The quality of the evidence for the outcomes reported ranged from high to very low. The risk of bias for many of the studies could not be determined for performance and detection bias, criteria that we assess as likely to impact the study outcomes.

AUTHORS' CONCLUSIONS

HS reduces the volume of intravenous fluid required to maintain people undergoing surgery but transiently increases serum sodium. It is not known if HS affects survival and morbidity, but this should be examined in randomized controlled trials that are designed and powered to test these outcomes.