Strong ion difference and gap predict outcomes after adult burn injury

Prognostic Significance of the Strong Ion Gap in Patients in Medical and Surgical Intensive Care Units

Background This study aimed to analyze acid-base imbalance by assessing the arterial blood gas (ABG) samples of the medical and surgical intensive care unit (ICU) patients by the Stewart approach and demonstrate the advantages of this method in delineating the acid-base status in cases where Henderson-Hasselbalch, anion gap, and base excess cannot optimally depict the imbalance and create recognition in the clinicians in this regard.  Methodology Adult (i.e., age > 18 years) patients admitted to the ICU of our institution during a one-year study period were included in this study. The patients were divided into two groups based on the indication of admission to the ICU as medical or surgical. The ABG, sodium, potassium, calcium, magnesium, phosphate, chloride, albumin, lactate, hemoglobin, hematocrit, leukocyte, blood urea nitrogen, and creatinine values determined during the first 24-hour period were used for calculating the Acute Physiologic Assessment and Chronic Health Evaluation (APACHE II), strong ion difference apparent (SIDa), and SID effective (SIDe) scores, which were subsequently compared between the groups.  Results Overall, 220 (110 medical and 110 surgical) patients were included. The mean patient age was 63.56 ± 18.08 years. The mean APACHE II scores were 21.99 and 19.63 in the medical and surgical groups, respectively. Overall, 110 patients died, while 110 were referred to the regular patient floor. The mean APACHE II score of the patients who died was 28.3, and the latter group had a mean APACHE II score of 13.57. There was a significant difference between the surgical and medical patient groups regarding mean values of APACHE II, SIDa, and SIDe scores. Also, the differences were significant between the patients who died and were discharged. There was a significant difference between the patients who died and were discharged regarding the strong ion gap (SIG); however, the medical and surgical patient groups were not different concerning the SIG values.  Conclusions We conclude that SIDa, SIDe, and SIG can be used in medical and surgical ICU patients to predict prognosis.

Role of Crystalloids in the Perioperative Setting: From Basics to Clinical Applications and Enhanced Recovery Protocols

Perioperative fluid management, a critical aspect of major surgeries, is characterized by pronounced stress responses, altered capillary permeability, and significant fluid shifts. Recognized as a cornerstone of enhanced recovery protocols, effective perioperative fluid management is crucial for optimizing patient recovery and preventing postoperative complications, especially in high-risk patients. The scientific literature has extensively investigated various fluid infusion regimens, but recent publications indicate that not only the volume but also the type of fluid infused significantly influences surgical outcomes. Adequate fluid therapy prescription requires a thorough understanding of the physiological and biochemical principles that govern the body's internal environment and the potential perioperative alterations that may arise. Recently published clinical trials have questioned the safety of synthetic colloids, widely used in the surgical field. A new clinical scenario has arisen in which crystalloids could play a pivotal role in perioperative fluid therapy. This review aims to offer evidence-based clinical principles for prescribing fluid therapy tailored to the patient's physiology during the perioperative period. The approach combines these principles with current recommendations for enhanced recovery programs for surgical patients, grounded in physiological and biochemical principles.

Utilization and Efficacy of Resuscitation Endpoints in Trauma and Burn Patients: A Review Article

Shock is a sequelae in trauma and burn patients that substantially increases the risk for morbidity and mortality. The use of resuscitation endpoints allows for improved management of these patients, with the potential to prevent further morbidity/mortality. We conducted a review of the current literature on the efficacy of hemodynamic, metabolic, and regional resuscitation endpoints for use in trauma and burn patients. Hemodynamic endpoints included mean arterial pressure (MAP), heart rate (HR), urinary output (UO), compensatory reserve index (CRI), intrathoracic blood volume, and stroke volume variation (SVV). Metabolic endpoints measure cellular responses to decreased oxygen delivery and include serum lactic acid (LA), base deficit (BD), bicarbonate, anion gap, apparent strong ion difference, and serum pH. Mean arterial pressure, HR, UO, and LA are the most established markers of trauma and burn resuscitation. The evidence suggests LA is a superior metabolic endpoint marker. Newer resuscitation endpoint technologies such as point-of-care ultrasound (PoCUS), thromboelastography (TEG), and rotational thromboelastometry (ROTEM) may improve patient outcomes; however, additional research is needed to establish the efficacy in trauma and burn patients. The endpoints discussed have situational strengths and weaknesses and no single universal resuscitation endpoint has yet emerged. This review may increase knowledge and aid in guideline development. We recommend clinicians continue to integrate multiple endpoints with emphasis on MAP, HR, UO, LA, and BD. Future investigation should aim to standardize endpoints for each clinical presentation. The search for universal and novel resuscitation parameters in trauma and burns should also continue.

Non-lactate strong ion difference and cardiovascular, cancer and all-cause mortality

Objectives

Non-lactate strong ion difference (SID) has been shown to be associated with predictors of mortality in intensive care unit. However, the existence of any association between non-lactate SID (nlSID) and all cause, cardiovascular and cancer mortality has not been explored before in community dwelling US adults.

Methods

In a nationally representative cross-sectional survey of the US non-institutionalized population, all adult participants (≥20 years of age) using National Health and Nutrition Examination Survey data (1999-2010) combined with National Death Index for mortality status through December 2011. Cox proportional hazard models were built to estimate the hazard ratios for cardiovascular, cancer, and all-cause mortality for each unit increase in non-lactate SID. The models were adjusted for demographic and confounder variables.

Results

In the study population the mean (SD) age was 49.6 (18.4) years. Of the study population, 31,475 (91.5%) were alive and 2,893 (8.4%) died during the mean (SD) follow-up period of 5.5 (3.5) years. In univariate regression model using nlSID as continuous variable, we found 2% (unadjusted hazard ratio, HR=1.02; 95% CI, 1.004-1.05) increase in all-cause but not in cardiovascular and cancer mortality (HR=1.03; 95% CI, 0.99-1.08, HR=1.01; 95% CI, 0.97-1.06). After adjusting for potential confounders, we found 7% (adjusted HR=1.07; 95% CI, 1.04-1.10), 5% (HR=1.05; 95% CI, 1.00-1.11) and 7% (HR=1.07; 95% CI, 1.02-1.12) increase in all-cause, cardiovascular, and cancer mortality.

Conclusions

A high nlSID is associated with an increase in cardiovascular, cancer and all-cause mortality and may be a prognostic indicator of mortality in general adult population. These findings may provide a point of reference for further studies.

Metabolic acidosis and the role of unmeasured anions in critical illness and injury

Acid-base disorders are frequently present in critically ill patients. Metabolic acidosis is associated with increased mortality, but it is unclear whether as a marker of the severity of the disease process or as a direct effector. The understanding of the metabolic component of acid-base derangements has evolved over time, and several theories and models for precise quantification and interpretation have been postulated during the last century. Unmeasured anions are the footprints of dissociated fixed acids and may be responsible for a significant component of metabolic acidosis. Their nature, origin, and prognostic value are incompletely understood. This review provides a historical overview of how the understanding of the metabolic component of acid-base disorders has evolved over time and describes the theoretical models and their corresponding tools applicable to clinical practice, with an emphasis on the role of unmeasured anions in general and several specific settings.

The effects of the chloride:sodium ratio on acid-base statusand mortality in septic patients

BACKGROUND/AIM

Calculation of the chloride:sodium (Cl^-:Na⁺) ratio is proposed to enable a quick evaluation of the effect of Cl^- and Na⁺ on the acid-base balance in critically ill patients. In the present study, the relationship of the Cl^-:Na⁺ ratio of septic patients with acid-base status and ICU mortality were investigated.

MATERIALS AND METHODS

In our two-center study, 434 patients who were diagnosed with sepsis were included. The patients were divided into three groups: low (<0.75), normal (≥0.75, <0.80), and high (≥0.80) Cl^-:Na⁺ ratio groups. Patients' demographic data, blood gas values, length of ICU stay, and ICU mortality were recorded.

RESULTS

In the low and high groups, ICU mortality was significantly higher than in the normal group (29.3%, 37.1%) (P = 0.005). There was a negative correlation between the Cl:Na⁺ ratio and each of HCO₃^-, standard base excess, and PaCO₂ (r² = 0.21, r² = 0.19, and r² = 0.17) (P < 0.001 for each). In the multivariate analysis, the ICU mortality was increased 2.6-fold (1.2-5.8) by low Cl^-:Na⁺ ratio (P = 0.019).

CONCLUSION

The Cl^-:Na⁺ ratio is a useful parameter for showing the relationship between Cl^- and Na⁺ and their impact on acid-base status. Low Cl^-:Na⁺ ratio at ICU admission can be used as a prognostic indicator for increased ICU mortality in septic patients.

A comparison of prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill: a cohort study

Background

This cohort study compared the prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill.

Methods

The relationships between SIG, lactate, anion gap (AG), anion gap albumin-corrected (AG-corrected), base excess or strong ion difference-effective (SIDe), all obtained within the first hour of intensive care unit (ICU) admission, and the hospital mortality of 6878 patients were analysed. The prognostic significance of each acid-base marker, both alone and in combination with the Admission Mortality Prediction Model (MPM₀ III) predicted mortality, were assessed by the area under the receiver operating characteristic curve (AUROC).

Results

Of the 6878 patients included in the study, 924 patients (13.4 %) died after ICU admission. Except for plasma chloride concentrations, all acid-base markers were significantly different between the survivors and non-survivors. SIG (with lactate: AUROC 0.631, confidence interval [CI] 0.611–0.652; without lactate: AUROC 0.521, 95 % CI 0.500–0.542) only had a modest ability to predict hospital mortality, and this was no better than using lactate concentration alone (AUROC 0.701, 95 % 0.682–0.721). Adding AG-corrected or SIG to a combination of lactate and MPM₀ III predicted risks also did not substantially improve the latter’s ability to differentiate between survivors and non-survivors. Arterial lactate concentrations explained about 11 % of the variability in the observed mortality, and it was more important than SIG (0.6 %) and SIDe (0.9 %) in predicting hospital mortality after adjusting for MPM₀ III predicted risks. Lactate remained as the strongest predictor for mortality in a sensitivity multivariate analysis, allowing for non-linearity of all acid-base markers.

Conclusions

The prognostic significance of SIG was modest and inferior to arterial lactate concentration for the critically ill. Lactate concentration should always be considered regardless whether physiological, base excess or physical-chemical approach is used to interpret acid-base disturbances in critically ill patients.

Non-lactate strong ion difference: a clearer picture

PURPOSE

The recommended method for elucidating the effects of strong ions other than lactate on acid-base balance is to calculate the non-lactate strong ion difference (SIDnl). A relationship between HCO3 (-) and SIDnl in hyperchloremic patients has already been demonstrated; in the present study, the relationships between SIDnl, the apparent strong ion difference (SIDa), and mortality at intensive care unit (ICU) admission were investigated.

METHODS

In our two-center study, 2691 patients admitted to the ICU were retrospectively evaluated, including 1069 critically ill patients. These patients were divided into three subgroups according to their SIDnl levels at admission to the ICU: low (<38 mmol L(-1)), normal (38-40 mmol L(-1)), and high (>40 mmol L(-1)). Patient age, gender, diagnosis, blood gas values, length of ICU stay, and mortality were recorded.

RESULTS

The low-SIDnl group included 768 patients (71.8 %), the normal-SIDnl group consisted of 127 patients (11.9 %), and the high-SIDnl group contained 174 patients (16.3 %). There was no significant difference in lactate levels among the SIDnl groups (p = 0.635). In a multivariate logistic regression model, likelihood of mortality was increased 1.24-fold (1.20-1.28), 2.56-fold (1.61-4.08) and 2.55-fold (1.003-6.47) by APACHE II, lactate level ≥2mmol L(-) and low SIDnl (p < 0.001, p < 0.001, and p = 0.049, respectively).

CONCLUSIONS

SIDnl can be used to determine the effects of strong ions other than lactate on SIDa values and acid-base balance. Furthermore, a low SIDnl at ICU admission can be a prognostic indicator of mortality.