Metabolic and electrolyte disturbance after cardiac arrest: How to deal with it

The early change in pH values after out-of-hospital cardiac arrest is not associated with neurological outcome at hospital discharge

Background

The association between pH values and outcome for patients after out-of-hospital cardiac arrest (OHCA) was not fully elucidated; besides, the relationship of change in pH values and neurological outcome was unknown. The aim was to explore the association of pH values as well as change in pH values and neurological outcome for OHCA cardiac patients.

Methods

The adult patients with non-traumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, and at least two arterial blood gases analysis recorded after admission were included. The change in pH values is calculated as the difference between the second and first pH value, and divided by time interval got the rate of change in pH values. The primary outcome was modified Rankin Score (mRS), dichotomized to good (mRS 0-3) and poor (mRS 4-6) outcomes at hospital discharge. The independent relationship of the first pH value, second pH value, and changes in pH values with neurological outcome was investigated with multivariable logistic regression models, respectively.

Results

A total of 1388 adult patients were included for analysis, of which 514 (37%) had good neurological outcome. The median first pH value and second pH value after admission were 7.21 (interquartile range [IQR] 7.09-7.29) and 7.28 (IQR 7.20-7.36), respectively. The median absolute, relative change, and rate of changes in pH values were 0.08 (IQR 0.01-0.16), 1.10% (IQR 0.11-2.22%), and 0.02 (IQR 0-0.06) per hour, respectively. After adjusting for confounders, the higher first pH value (odds ratio [OR] 3.81, confidence interval [CI] 1.60-9.24, P = 0.003) and higher second pH value (OR 9.54, CI 3.45-26.87, P < 0.001) after admission were associated with good neurological outcome, respectively. The absolute (OR 1.58, CI 0.58-4.30, P = 0.368) and relative (OR 1.03, CI 0.96-1.11, P = 0.399) change as well as the rate of change (OR 0.98, CI 0.33-2.71, P = 974) in pH values were not associated with neurological outcome.

Conclusions

For OHCA patients, abnormality in pH values was very common, with a more acidic pH value indicating poor neurological outcome. However, the change in pH values was not associated with outcomes.

Ketone Bodies after Cardiac Arrest: A Narrative Review and the Rationale for Use

Cardiac arrest survivors suffer the repercussions of anoxic brain injury, a critical factor influencing long-term prognosis. This injury is characterised by profound and enduring metabolic impairment. Ketone bodies, an alternative energetic resource in physiological states such as exercise, fasting, and extended starvation, are avidly taken up and used by the brain. Both the ketogenic diet and exogenous ketone supplementation have been associated with neuroprotective effects across a spectrum of conditions. These include refractory epilepsy, neurodegenerative disorders, cognitive impairment, focal cerebral ischemia, and traumatic brain injuries. Beyond this, ketone bodies possess a plethora of attributes that appear to be particularly favourable after cardiac arrest. These encompass anti-inflammatory effects, the attenuation of oxidative stress, the improvement of mitochondrial function, a glucose-sparing effect, and the enhancement of cardiac function. The aim of this manuscript is to appraise pertinent scientific literature on the topic through a narrative review. We aim to encapsulate the existing evidence and underscore the potential therapeutic value of ketone bodies in the context of cardiac arrest to provide a rationale for their use in forthcoming translational research efforts.

Higher Prehospital Blood Glucose Levels Associated With Return of Spontaneous Circulation in Out-of-Hospital Non-traumatic Cardiac Arrests

OBJECTIVE

Cardiac arrest leads to an array of metabolic disturbances. We aimed to investigate the association between prehospital blood glucose levels (BGLs) and rates of return of spontaneous circulation (ROSC) in non-traumatic out-of-hospital cardiac arrests (OHCAs).

METHODS

A retrospective analysis of adult non-traumatic OHCAs within Kalamazoo County, MI, from January 2018 to May 2020 using the Michigan Emergency Medical Services Information System database was performed. Demographic data, Utstein variables, and BGLs (hypoglycemia < 70 mg/dL, euglycemia 70-120 mg/dL, and hyperglycemia >120 mg/dL) were abstracted. Chi-square and Wilcoxon rank sum tests were used to evaluate the relationship between BGL and ROSC.

RESULTS

In total, 314 patients met the inclusion criteria. The mean age was 62.9 years. ROSC was achieved in 147 (46.8%) patients. Fifty (15.9%), 75 (23.9%), and 189 (60.2%) patients were hypoglycemic, euglycemic, and hyperglycemic, respectively. An association was found between the glycemic group and ROSC (P < .0001), with an estimated odds of ROSC being 77% lower (95% confidence interval, 46%-90%) for hypoglycemic than euglycemic or hyperglycemic patients. The point difference between median ROSC-yes BGL (median [interquartile range] = 160 mg/dL [110-225 mg/dL]) was 33 mg/dL (95% CI, 13-51 mg/dL) greater than the ROSC-no group (median [interquartile range] = 127 mg/dL [75-190 mg/dL], P = .001).

CONCLUSION

Non-traumatic OHCA patients achieving ROSC had a significantly higher prehospital BGL than the ROSC-no group. Further study is warranted to investigate the role intra-arrest BGL may have as a prognostic marker for ROSC.

Massive Transfusion Increases Serum Magnesium Concentration

(1) Background: The massive transfusion of packed red blood cells (RBCs) is a lifesaving procedure, but it is associated with complications, e.g., dysmagnesemia. Since magnesium is an intracellular ion, the transfused RBCs can significantly influence the magnesium concentration in the recipient's blood. (2) Methods: A retrospective study was performed among 49 patients hospitalized in the Central Clinical Hospital of the Medical University of Warsaw who received a massive blood transfusion (≥4 units/h). Data on laboratory results and patient history were collected from the hospital database. The intracellular RBCs magnesium concentration was measured in 231 samples using the colorimetric method. (3) Results: There were statistically significant changes in the mean serum magnesium concentration preoperatively and 24 h postoperatively (0.87 ± 0.13 vs. 1.03 ± 0.14, p < 0.00001) and 48 h postoperatively (0.87 ± 0.13 vs. 1.06 ± 0.15, p < 0.00001). Patients who died had significantly higher serum magnesium concentrations (p < 0.05). The median intracellular magnesium concentration in RBCs was 0.91 (0.55-1.8) mmol/L, which is below the reference values of 1.65-2.65 mmol/L. (4) Conclusions: Transfused RBCs significantly increased the serum magnesium concentration 24 h and 48 h postoperatively. It could be a result of mild hemolysis, as the median intracellular magnesium concentration in RBCs was below the reference values.

Thrombotic Microangiopathy Score as a New Predictor of Neurologic Outcomes in Patients after Out-of-Hospital Cardiac Arrest

PURPOSE

Given the morphological characteristics of schistocytes, thrombotic microangiopathy (TMA) score can be beneficial as it can be automatically and accurately measured. This study aimed to investigate whether serial TMA scores until 48 h post admission are associated with clinical outcomes in patients undergoing targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA).

MATERIALS AND METHODS

We retrospectively evaluated a cohort of 185 patients using a prospective registry. We analyzed TMA scores at admission and after 12, 24, and 48 hours. The primary outcome measures were poor neurological outcome at discharge and 30-day mortality.

RESULTS

Increased TMA scores at all measured time points were independent predictors of poor neurological outcomes and 30-day mortality, with TMA score at time-12 showing the strongest correlation [odds ratio (OR), 3.008; 95% confidence interval (CI), 1.707-5.300; p<0.001 and hazard ratio (HR), 1.517; 95% CI, 1.196-1.925; p<0.001]. Specifically, a TMA score ≥2 at time-12 was closely associated with an increased predictability of poor neurological outcomes (OR, 6.302; 95% CI, 2.841-13.976; p<0.001) and 30-day mortality (HR, 2.656; 95% CI, 1.675-4.211; p<0.001).

CONCLUSION

Increased TMA scores predicted neurological outcomes and 30-day mortality in patients undergoing TTM after OHCA. In addition to the benefit of being serially measured using an automated hematology analyzer, TMA score may be a helpful tool for rapid risk stratification and identification of the need for intensive care in patients with return of spontaneous circulation after OHCA.

Electrolyte profiles with induced hypothermia: A sub study of a clinical trial evaluating the duration of hypothermia after cardiac arrest

Background

Electrolyte disturbances can result from targeted temperature treatment (TTM) in out‐of‐hospital cardiac arrest (OHCA) patients. This study explores electrolyte changes in blood and urine in OHCA patients treated with TTM.

Methods

This is a sub‐study of the TTH48 trial, with the inclusion of 310 unconscious OHCA patients treated with TTM at 33°C for 24 or 48 h. Over a three‐day period, serum concentrations were obtained on sodium potassium, chloride, ionized calcium, magnesium and phosphate, as were results from a 24‐h diuresis and urine electrolyte concentration and excretion. Changes over time were analysed with a mixed‐model multivariate analysis of variance with repeated measurements.

Results

On admission, mean ± SD sodium concentration was 138 ± 3.5 mmol/l, which increased slightly but significantly (p < .05) during the first 24 h. Magnesium concentration stayed within the reference interval. Median ionized calcium concentration increased from 1.11 (IQR 1.1–1.2) mmol/l during the first 24 h (p < .05), whereas median phosphate concentration dropped to 1.02 (IQR 0.8–1.2) mmol/l (p < .05) and stayed low. During rewarming, potassium concentrations increased, and magnesium and ionizes calcium concentration decreased (p < .05). Median 24‐h diuresis results on days one and two were 2198 and 2048 ml respectively, and the electrolyte excretion mostly stayed low in the reference interval.

Conclusions

Electrolytes mostly remained within the reference interval. A temporal change occurred in potassium, magnesium and calcium concentrations with TTM’s different phases. No hypothermia effect on diuresis was detected, and urine excretion of electrolytes mostly stayed low.

The role of the lactate/albumin ratio in predicting survival outcomes in patients resuscitated after out-of-hospital cardiac arrest: A preliminary report

OBJECTIVE

To investigate the effect of lactate/albumin (L/A) ratio on survival to discharge in patients who have had out-of-hospital cardiac arrest (OHCA).

METHODS

We analyzed adult patients (aged ≥18 years) who were admitted to our hospital's emergency department (ED) due to OHCA between January 2018 and June 2020 and who achieved return of spontaneous circulation after successful resuscitation. Blood lactate and albumin concentrations were obtained within the first 10 min after admission to the ED. Patients were grouped according to clinical outcomes. The primary outcome was survival until hospital discharge. The groups were then statistically compared.

RESULTS

In this study, 235 OHCA patients were analyzed, 42 (17.9%) of whom had survived until discharge. The L/A ratio was higher in the non-survivor group than in the survivor group (2.0 (interquartile range: 1.4-2.8) vs 1.4 (0.9-1.9); P < 0.001). A low L/A ratio was significantly associated with survival at discharge (odds ratio: 2.55; 95% confidence interval (CI): 3.24-11.08; P < 0.001). In the prediction of survival to discharge, the area under the curve (AUC) for the L/A ratio (AUC: 0.823) was higher than that for lactate (AUC: 0.762) or albumin (AUC: 0.722) alone. Moreover, the predictive value of L/A ratio for survival to discharge might significantly improve when the cutoff value is higher than 1.62.

CONCLUSION

The L/A ratio is more valuable than the lactate or albumin levels alone in predicting survival to discharge. Our findings indicate that a combination of these parameters might increase the predictability of survival to discharge in OHCA patients.

Usefulness of chloride levels for fluid resuscitation in patients undergoing targeted temperature management after out-of-hospital cardiac arrest

OBJECTIVE

Chloride is an important electrolyte in the body. In this study, we aimed to evaluate the associations between chloride levels on emergency department (ED) admission and neurologic outcomes by stratifying patients undergoing targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) into three groups (hyper/normo/hypochloremia); we also assessed the effect of changes in chloride levels from baseline over time on outcomes.

METHODS

This retrospective, observational cohort study of 346 patients was conducted between 2011 and 2019. The chloride levels were categorized as hypochloremia, normochloremia, and hyperchloremia by predetermined definitions. The primary endpoint was poor neurologic outcomes after hospital discharge. We evaluated the associations between chloride levels on ED admission and neurologic outcomes and assess the effect of changes in chloride levels over time on clinical outcomes.

RESULTS

On ED admission, compared with normochloremia, hypochloremia was significantly associated with unfavorable neurologic outcomes (OR, 2.668; 95% CI, 1.217-5.850, P = 0.014). Over time, unfavorable neurologic outcomes were significantly associated with increases in chloride levels in the hyperchloremia and normochloremia groups after ED admission. The rates of poor neurologic outcomes in the hyperchloremia and normochloremia groups were increased by 14.2% at Time-12, 20.1% at Time-24, and 9.3% at Time-48 with a 1-mEq/L increase in chloride levels.

CONCLUSION

In clinical practice, chloride levels can be routinely and serially measured cost-effectively. Thus, baseline chloride levels may be a promising tool for rapid risk stratification of patients after OHCA. For fluid resuscitation after cardiac arrest, a chloride-restricted solution may be an early therapeutic strategy.

Ionized calcium level at emergency department arrival is associated with return of spontaneous circulation in out-of-hospital cardiac arrest

BACKGROUND

Calcium level is associated with sudden cardiac death based on several cohort studies. However, there is limited evidence on the association between ionized calcium, active form of calcium, and resuscitation outcome. This study aimed to evaluate the potential role of ionized calcium in predicting resuscitation outcome in patients with out-of-hospital cardiac arrest.

METHODS

We analyzed the Korean Cardiac Arrest Research Consortium data (KoCARC) registry, a web-based multicenter registry that included 65 participating hospitals throughout the Republic of Korea. The patients with out-of-hospital cardiac arrest over 19 years old and acquired laboratory data including calcium, ionized calcium, potassium, phosphorus, creatinine, albumin at emergency department (ED) arrival were included. The primary outcome was successful rate of return of spontaneous circulation (ROSC) and the secondary outcomes were survival hospital discharge and favorable neurological outcome (cerebral performance category 1 or 2) at hospital discharge.

RESULTS

Eight-hundred and eighty-three patients were enrolled in the final analysis and 448 cases (54%) had ROSC. In multivariable logistic regression analysis, ionized calcium level was associated with ROSC (odds ratio, 1.77; 95% CI1.28-2.45; p = 0.001) even though calcium level was not associated with ROSC (odds ratio, 0.87; 95% CI 0.70-1.08; p = 0.199). However, ionized calcium level was not associated with survival discharge (odds ratio, 0.99; 95% CI 0.72-1.36; p = 0.948) or favorable neurologic outcome (odds ratio, 0.45; 95% CI 0.03-6.55, p = 0.560).

CONCLUSION

A high ionized calcium level measured during cardiopulmonary resuscitation was associated with an increased likelihood of ROSC.

Targeted temperature management guided by the severity of hyperlactatemia for out-of-hospital cardiac arrest patients: a post hoc analysis of a nationwide, multicenter prospective registry

Background

The International Liaison Committee on Resuscitation guidelines recommend target temperature management (TTM) between 32 and 36 °C for patients after out-of-hospital cardiac arrest, but did not indicate patient-specific temperatures. The association of serum lactate concentration and neurological outcome in out-of-hospital cardiac arrest patient has been reported. The study aim was to investigate the benefit of 32–34 °C in patients with various degrees of hyperlactatemia compared to 35–36 °C.

Methods

This study was a post hoc analysis of the Japanese Association for Acute Medicine out-of-hospital cardiac arrest registry between June 2014 and December 2015. Patients with complete targeted temperature management and lactate data were eligible. Patients were stratified to mild (< 7 mmol/l), moderate (< 12 mmol/l), or severe (≥ 12 mmol/l) hyperlactatemia group based on lactate concentration after return of spontaneous circulation. They were subdivided into 32–34 °C or 35–36 °C groups. The primary endpoint was an adjusted predicted probability of 30-day favorable neurological outcome, defined as a cerebral performance category score of 1 or 2.

Result

Of 435 patients, 139 had mild, 182 had moderate, and 114 had severe hyperlactatemia. One hundred and eight (78%) with mild, 128 with moderate (70%), and 83 with severe hyperlactatemia (73%) received TTM at 32–34 °C. The adjusted predicted probability of a 30-day favorable neurological outcome following severe hyperlactatemia was significantly greater with 32–34 °C (27.4%, 95% confidence interval: 22.0–32.8%) than 35–36 °C (12.4%, 95% CI 3.5–21.2%; p = 0.005). The differences in outcomes in those with mild and moderate hyperlactatemia were not significant.

Conclusions

In OHCA patients with severe hyperlactatemia, the adjusted predicted probability of 30-day favorable neurological outcome was greater with TTM at 32–34 °C than with TTM at 35–36 °C. Further evaluation is needed to determine whether TTM at 32–34 °C can improve neurological outcomes in patients with severe hyperlactatemia after out-of-hospital cardiac arrest.

[Postcardiac arrest treatment guide]

BACKGROUND

Treatment after cardiac arrest has become more complex and interdisciplinary over the last few years. Thus, the clinically active intensive and emergency care physician not only has to carry out the immediate care and acute diagnostics, but also has to prognosticate the neurological outcome.

AIM

The different, most important steps are presented by leading experts in the area, taking into account the interdisciplinarity and the currently valid guidelines.

MATERIALS AND METHODS

Attention was paid to a concise, practice-oriented presentation.

RESULTS AND DISCUSSION

The practical guide contains all important steps from the acute care to the neurological prognosis generation that are relevant for the clinically active intensive care physician.

Mechanisms of early glucose regulation disturbance after out-of-hospital cardiopulmonary resuscitation: An explorative prospective study

Background

Hyperglycemia is common and associated with increased mortality after out-of-hospital cardiac arrest (OHCA) and return of spontaneous circulation (ROSC). Mechanisms behind ultra-acute hyperglycemia are not well known. We performed an explorative study to describe the changes in glucose metabolism mediators during the prehospital postresuscitation phase.

Methods

We included patients who were successfully resuscitated from out-of-hospital cardiac arrest in two physician-staffed units. Insulin, glucagon, and glucagon-like peptide 1 (GLP-1) were measured in prehospital and hospital admission samples. Additionally, interleukin-6 (IL-6), cortisol, and HbA1c were measured at hospital admission.

Results

Thirty patients participated in the study. Of those, 28 cases (71% without diabetes) had sufficient data for analysis. The median time interval between prehospital samples and hospital admission samples was 96 minutes (IQR 85–119). At the time of ROSC, the patients were hyperglycemic (11.2 mmol/l, IQR 8.8–15.7), with insulin and glucagon concentrations varying considerably, although mostly corresponding to fasting levels (10.1 mU/l, IQR 4.2–25.2 and 141 ng/l, IQR 105–240, respectively). GLP-1 increased 2- to 8-fold with elevation of IL-6. The median glucose change from prehospital to hospital admission was -2.2 mmol/l (IQR -3.6 to -0.2). No significant correlations between the change in plasma glucose levels and the changes in insulin (r = 0.30, p = 0.13), glucagon (r = 0.29, p = 0.17), or GLP-1 levels (r = 0.32, p = 0.15) or with IL-6 (r = (-0.07), p = 0.75), cortisol (r = 0.13, p = 0.52) or HbA1c levels (r = 0.34, p = 0.08) were observed. However, in patients who did not receive exogenous epinephrine during resuscitation, changes in blood glucose correlated with changes in insulin (r = 0.59, p = 0.04) and glucagon (r = 0.65, p = 0.05) levels, demonstrating that lowering glucose values was associated with a simultaneous lowering of insulin and glucagon levels.

Conclusions

Hyperglycemia is common immediately after OHCA and cardiopulmonary resuscitation. No clear hormonal mechanisms were observed to be linked to changes in glucose levels during the postresuscitation phase in the whole cohort. However, in patients without exogenous epinephrine treatment, the correlations between glycemic and hormonal changes were more obvious. These results call for future studies examining the mechanisms of postresuscitation hyperglycemia and the metabolic effects of the global ischemic insult and medical treatment.

Early Administration of Glutamine Protects Cardiomyocytes from Post-Cardiac Arrest Acidosis

Postcardiac arrest acidosis can decrease survival. Effective medications without adverse side effects are still not well characterized. We aimed to analyze whether early administration of glutamine could improve survival and protect cardiomyocytes from postcardiac arrest acidosis using animal and cell models. Forty Wistar rats with postcardiac arrest acidosis (blood pH < 7.2) were included. They were divided into study (500 mg/kg L-alanyl-L-glutamine, n = 20) and control (normal saline, n = 20) groups. Each of the rats received resuscitation. The outcomes were compared between the two groups. In addition, cardiomyocytes derived from human induced pluripotent stem cells were exposed to HBSS with different pH levels (7.3 or 6.5) or to culture medium (control). Apoptosis-related markers and beating function were analyzed. We found that the duration of survival was significantly longer in the study group (p < 0.05). In addition, in pH 6.5 or pH 7.3 HBSS buffer, the expression levels of cell stress (p53) and apoptosis (caspase-3, Bcl-xL) markers were significantly lower in cardiomyocytes treated with 50 mM L-glutamine than those without L-glutamine (RT-PCR). L-glutamine also increased the beating function of cardiomyocytes, especially at the lower pH level (6.5). More importantly, glutamine decreased cardiomyocyte apoptosis and increased these cells' beating function at a low pH level.

A systematic review and meta-analysis of the association between arterial carbon dioxide tension and outcomes after cardiac arrest

INTRODUCTION

Arterial carbon dioxide tension (PaCO₂) abnormalities are common after cardiac arrest (CA). Maintaining a normal PaCO₂ makes physiological sense and is recommended as a therapeutic target after CA, but few studies have examined the association between PaCO₂ and patient outcomes. This systematic review and meta-analysis aimed to assess the effect of a low or high PaCO₂ on patient outcomes after CA.

METHODS

We searched MEDLINE, EMBASE, CINAHL and Cochrane CENTRAL, for studies that evaluated the association between PaCO₂ and outcomes after CA. The primary outcome was hospital survival. Secondary outcomes included neurological status at the end of each study's follow up period, hospital discharge destination and 30-day survival. Meta-analysis was conducted if statistical heterogeneity was low.

RESULTS

The systematic review included nine studies; eight provided sufficient quantitative data for meta-analysis. Using PaCO₂ cut-points of <35mmHg and >45mmHg to define hypo- and hypercarbia, normocarbia was associated with increased hospital survival (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.23, 1.38). Normocarbia was also associated with a good neurological outcome (cerebral performance category score 1 or 2) compared to hypercarbia (OR 1.69, 95% CI 1.13, 2.51) when the analysis also included an additional study with a slightly different definition for normocarbia (PaCO₂ 30-50mmHg).

CONCLUSIONS

From the limited data it appears PaCO₂ has an important U-shape association with survival and outcomes after CA, consistent with international resuscitation guidelines' recommendation that normocarbia be targeted during post-resuscitation care.