Severe metabolic or mixed acidemia on intensive care unit admission: incidence, prognosis and administration of buffer therapy. A prospective, multiple-center study

Construction and validation of a nomogram for predicting survival in elderly patients with severe acute pancreatitis: a retrospective study from a tertiary center

PURPOSE

There is a lack of adequate models specifically designed for elderly patients with severe acute pancreatitis (SAP) to predict the risk of death. This study aimed to develop a nomogram for predicting the overall survival of SAP in elderly patients.

METHODS

Elderly patients diagnosed with SAP between January 1, 2017 and December 31, 2022 were included in the study. Risk factors were identified through least absolute shrinkage and selection operator regression analysis. Subsequently, a novel nomogram model was developed using multivariable logistic regression analysis. The predictive performance of the nomogram was evaluated using metrics such as the receiver operating characteristic curve, calibration curve, and decision curve analysis (DCA).

RESULTS

A total of 326 patients were included in the analysis, with 260 in the survival group and 66 in the deceased group. Multivariate logistic regression indicated that age, respiratory rate, arterial pH, total bilirubin, and calcium were independent prognostic factors for the survival of SAP patients. The nomogram demonstrated a performance comparable to sequential organ failure assessment (P = 0.065). Additionally, the calibration curve showed satisfactory predictive accuracy, and the DCA highlighted the clinical application value of the nomogram.

CONCLUSION

We have identified key demographic and laboratory parameters that are associated with the survival of elderly patients with SAP. These parameters have been utilized to create a precise and user-friendly nomogram, which could be an effective and valuable clinical tool for clinicians.

Trimatch comparison of the prognosis of hypochloremia, normolchloremia and hyperchloremia in patients with septic shock

BACKGROUND

Septic shock is a lethal disease, and identifying high-risk patients through noninvasive and widely available biomarkers can help improve global outcomes. While the clinical impact of chloride levels on critically ill patients remains unclear, this study aims to investigate the association between hypochloremia and mortality following ICU admission among septic shock patients.

METHODS

This is an analysis of data stored in the databases of Medical Information Mart for Intensive Care IV (MIMIC-IV). The initial chloride levels were classified ashypochloremia, normal chloraemia, and hyperchloraemia. A multivariate logistic regression model was applied, adjusting for age, lactate, pH, PO2, urine volume, RDW, creatinine, and liver disease, to assess the association between the three categories of chloride levels and mortality.

RESULTS

Of 3726 patients included in the study, 470 patients (12.6%) had hypochloremia on ICU admission. During the follow-up period, 1120 (33.5%) patients died. Hypochloremia was significantly associated with increased mortality and the incidence of AKI after adjusting for several variables.

CONCLUSIONS

Hypochloremia is independently associated with higher hospital mortality, AKI incidence among septic shock patients. However, further high-quality research is necessary to establish the precise relationship between hypochloremia and septic shock prognosis.

Survival and Vision Restoration Following Severe Metformin-associated Metabolic Acidosis With Transient Blindness: A Case Report and Review of the Literature

Metformin-associated lactic acidosis (MALA) is a life-threatening condition that may occur as a side effect of biguanides. This condition has a mortality rate of approximately 55 % depending on the severity. Typical symptoms include abdominal pain, nausea, vomiting, and diarrhea, but may also manifest with severe symptoms such as blindness, distributive shock, and renal failure requiring ICU level care. We present the case of a female in her early 70s who arrived at the emergency department with altered mental status and new-onset blindness, later diagnosed with severe acidosis (pH 6.607). She was intubated for hemodynamic instability and continuous renal replacement therapy (CRRT) was started to address her acid-base status. Her metformin concentration was found to be exceptionally high at 34 mcg/ml, significantly surpassing the normal range of 1-2 mcg/ml. Fortunately, the patient survived and was subsequently transferred to the medical floors in stable condition. Physicians should perform medication review and consider "MALA" as a potential etiology of severe acidosis when forming a differential diagnosis.

Additional Bicarbonate Infusion Complements WHO Rehydration Therapy in Children with Acute Diarrhea and Severe Dehydration Presenting with Severe Non-anion Gap Metabolic Acidemia: An Open Label Randomized Trial

OBJECTIVES

To assess the efficacy and safety of bicarbonate infusion in children with Acute Diarrhea and Severe Dehydration (ADSD) having severe Non-Anion Gap Metabolic Acidemia (sNAGMA).

METHODS

Children (aged 1-144 mo) with ADSD and sNAGMA (pH ≤7.2 and/or serum bicarbonate ≤15 mEq/L) were enrolled in an open-label randomized design. Controls (n = 25) received WHO-recommended rehydration therapy with Ringer Lactate, while intervention group (n = 25) received additional bicarbonate deficit correction. Primary outcome was time taken to resolve metabolic acidemia (pH >7.30 and/or bicarbonate >15 mEq/L). Secondary outcome measures were adverse outcome [composite of pediatric intensive care unit (PICU) transfer and deaths], acute care area free days in 5 d (ACAFD5), hospital stay, and adverse effects.

RESULTS

Time taken to resolve metabolic acidemia was significantly lesser with intervention [median (IQR); 8 h (4, 12) vs. 12 h (8, 24); p = 0.0067]. Intervention led to acidemia resolution in significantly more children by 8 h and 16 h (17/25 vs. 9/25, p = 0.035 and 23/25 vs. 17/24, p = 0.018, respectively). Patients with fluid refractory shock needed lesser inotropes in intervention group [median Vasoactive Inotrope Score (VIS), 10.5 vs. 34]. Intervention led to significantly lesser adverse outcome (0/25 vs. 5/25, p = 0.049), and noticeably more ACAFD5 [median (IQR); 2 (1, 2) vs. 1 (1, 2); p = 0.12]. Two patients died in the control group while none in the intervention group. No adverse effect was documented.

CONCLUSIONS

Additional calculated dose of bicarbonate infusion led to significantly early resolution of metabolic acidemia, lesser utilization of critical care facilities, and lesser adverse outcome in children with ADSD and sNAGMA, compared to standard therapy, with no adverse effect.

Prognosis of critically ill patients with extreme acidosis: A retrospective study

OBJECTIVE

This study aims to assess the impact of different subtypes of extreme acidosis on the mortality of critically ill patients.

METHODS

This retrospective cohort study included critically ill patients who were admitted to the intensive care unit (ICU) with a pH level <7. Clinical data and blood gas analyses were collected from electronic medical records. The primary outcome was in-hospital mortality. The use of vasopressors, mechanical ventilation (MV), and renal replacement therapy (RRT), the duration of MV and RRT, and the length of ICU and hospital stay were secondary outcomes. The simplified Stewart approach to acid-base disorders was used to analyze the causes of acidosis.

RESULTS

A total of 231 patients with 371 arterial blood gas analyses with pH < 7 were admitted from January 2012 to December 2021 and 222 were included in the study. Out of the 222 patients analyzed, respiratory acidosis was the primary disorder in 11.3% of patients (n = 25), metabolic acidosis in 33.8% (n = 75), and mixed acidosis in 55% (n = 122). Overall mortality was 42.8% (n = 95). No significant difference was observed in mortality among patients with respiratory, metabolic, or mixed acidosis (28%, 42.7%, and 45.9%, respectively; p = 0.26). The primary disorder affected the use of vasopressors and MV, the duration of MV, and the length of ICU and hospital stay. Patients with extreme acidosis due to unmeasured anions with lactate levels of 4 mmol/L or higher had higher mortality compared with patients with lactate levels <4 mmol/L (55.6% and 27.7%, respectively; p = 0.007).

CONCLUSION

Among critically ill patients with extreme acidosis, the primary disorder is not associated with mortality, but it is associated with the use of vasopressors and MV, the duration of MV, and the length of ICU and hospital stay. Additionally, hyperlactatemia is a predictor of poor prognosis in patients with extreme acidosis.

Dissecting Clinical Features of COVID-19 in a Cohort of 21,312 Acute Care Patients

COVID-19 has resulted in over 645 million hospitalization and 7 million deaths globally. However, many questions still remain about clinical complications in COVID-19 and if these complications changed with different circulating SARS-CoV-2 strains. We analyzed a 2.5-year retrospective cohort of 47,063 encounters for 21,312 acute care patients at five Central Texas hospitals and define distinct trajectory groups (TGs) with latent class mixed modeling, based on the World Health Organization COVID-19 Ordinal Scale. Using this TG framework, we evaluated the association of demographics, diagnoses, vitals, labs, imaging, consultations, and medications with COVID-19 severity and broad clinical outcomes. Patients within 6 distinct TGs differed in manifestations of multi-organ disease and multiple clinical factors. The proportion of mild patients increased over time, particularly during Omicron waves. Age separated mild and fatal patients, though did not distinguish patients with severe versus critical disease. Male and Hispanic/Latino demographics were associated with more severe/critical TGs. More severe patients had a higher rate of neuropsychiatric diagnoses, consultations, and brain imaging, which did not change significantly in severe patients across SARS-CoV-2 variant waves. More severely affected patients also demonstrated an immunological signature of high neutrophils and immature granulocytes, and low lymphocytes and monocytes. Interestingly, low albumin was one of the best lab predictors of COVID-19 severity in association with higher malnutrition in severe/critical patients, raising concern of nutritional insufficiency influencing COVID-19 outcomes. Despite this, only a small fraction of severe/critical patients had nutritional labs checked (pre-albumin, thiamine, Vitamin D, B vitamins) or received targeted interventions to address nutritional deficiencies such as vitamin replacement. Our findings underscore the significant link between COVID-19 severity, neuropsychiatric complications, and nutritional insufficiency as key risk factors of COVID-19 outcomes and raise the question of the need for more widespread early assessment of patients' neurological, psychiatric, and nutritional status in acute care settings to help identify those at risk of severe disease outcomes.

Sodium bicarbonate for the treatment of severe metabolic acidosis with moderate or severe acute kidney injury in the critically ill: protocol for a randomised clinical trial (BICARICU-2)

INTRODUCTION

When both severe metabolic acidemia (pH equal or less than 7.20; PaCO2 equal or less than 45 mm Hg and bicarbonate concentration equal or less than of 20 mmol/L) and moderate-to-severe acute kidney injury are observed, day 28 mortality is approximately 55%-60%. A multiple centre randomised clinical trial (BICARICU-1) has suggested that sodium bicarbonate infusion titrated to maintain the pH equal or more than 7.30 is associated with a higher survival rate (secondary endpoint) in a prespecified stratum of patients with both severe metabolic acidemia and acute kidney injury patients. Whether sodium bicarbonate infusion may improve survival at day 90 (primary outcome) in these severe acute kidney injury patients is currently unknown.

METHODS AND ANALYSIS

The sodium bicarbonate for the treatment of severe metabolic acidosis with moderate or severe acute kidney injury in the critically ill: a randomised clinical trial (BICARICU-2) trial is an investigator-initiated, multiple centre, stratified, parallel-group, unblinded trial with a computer-generated allocation sequence and an electronic system-based randomisation. After randomisation, the intervention group will receive 4.2% sodium bicarbonate infusion to target a plasma pH equal or more than 7.30 while the control group will not receive sodium bicarbonate. The primary outcome is the day 90 mortality. Main secondary outcomes are organ support dependences.

ETHICS AND DISSEMINATION

The trial has been approved by the appropriate ethics committee (CPP Nord Ouest, Rouen, France, 25 April 2019, number: 19.03.15.72446). Informed consent is required. If sodium bicarbonate improves day 90 mortality, it will become part of the routine care.

TRIAL REGISTRATION NUMBER

NCT04010630.

Factors to consider during anesthesia in patients undergoing preemptive kidney transplantation: a propensity-score matched analysis

BACKGROUND

International guidelines have recommended preemptive kidney transplantation (KT) as the preferred approach, advocating for transplantation before the initiation of dialysis. This approach is advantageous for graft and patient survival by avoiding dialysis-related complications. However, recipients of preemptive KT may undergo anesthesia without the opportunity to optimize volume status or correct metabolic disturbances associated with end-stage renal disease. In these regard, we aimed to investigate the anesthetic events that occur more frequently during preemptive KT compared to nonpreemptive KT.

METHODS

This is a single-center retrospective study. Of the 672 patients who underwent Living donor KT (LDKT), 388 of 519 who underwent nonpreemptive KT were matched with 153 of 153 who underwent preemptive KT using propensity score based on preoperative covariates. The primary outcome was intraoperative hypotension defined as area under the threshold (AUT), with a threshold set at a mean arterial blood pressure below 70 mmHg. The secondary outcomes were intraoperative metabolic acidosis estimated by base excess and serum bicarbonate, electrolyte imbalance, the use of inotropes or vasopressors, intraoperative transfusion, immediate graft function evaluated by the nadir creatinine, and re-operation due to bleeding.

RESULTS

After propensity score matching, we analyzed 388 and 153 patients in non-preemptive and preemptive groups. The multivariable analysis revealed the AUT of the preemptive group to be significantly greater than that of the nonpreemptive group (mean ± standard deviation, 29.7 ± 61.5 and 14.5 ± 37.7, respectively, P = 0.007). Metabolic acidosis was more severe in the preemptive group compared to the nonpreemptive group. The differences in the nadir creatinine value and times to nadir creatinine were statistically significant, but clinically insignificant.

CONCLUSION

Intraoperative hypotension and metabolic acidosis occurred more frequently in the preemptive group during LDKT. These findings highlight the need for anesthesiologists to be prepared and vigilant in managing these events during surgery.

A case of metformin-associated lactic acidosis with cardiogenic and vasoplegic shock supported by ECPella

Metfomin-associated lactic acidosis (MALA) is a rare but life-threatening complication of metformin use. We present a case of MALA with concurrent cardiogenic and vasoplegic shock which was successfully supported by ECPella (concurrent use of VA-ECMO and Impella). Early recognition, aggressive hemodynamic support with ECPella and early hemodialysis can be life-saving. Monitoring of both lactate and SvO2 trends can help understand the response to treatment.

Decompensated metabolic acidosis in the emergency department: Epidemiology, sodium bicarbonate therapy, and clinical outcomes

Objective

This article aims to describe the epidemiology of decompensated metabolic acidosis, the characteristics of sodium bicarbonate (SB) administration and outcomes in emergency department (ED) patients.

Design

This is a retrospective cohort study.

Setting

ED of a tertiary referral hospital in Melbourne, Australia.

Participants

Adult patients presenting to the ED between 1 July 2011 and 20 September 2020 with decompensated metabolic acidosis diagnosed on arterial blood gas (ABG).

Main outcome measures

We compared characteristics between those treated with or without SB. We studied SB administration characteristics, change in laboratory variables, factors associated with use and dose, and clinical outcomes.

Results

Among 753,613 ED patients, 314 had decompensated metabolic acidosis on ABG, with 17.8% receiving SB. Patients in the SB group had lower median pH, CO2, bicarbonate, and base excess (BE) levels compared with the No SB group (P < 0.01). The median number of SB doses in the SB group was one treatment. This was given at a median total dose of 100 mmol and at a median of 2.8 h after the diagnostic blood gas results. Only 42% of patients in the SB group had a subsequent blood gas measured. In such patients, there was no significant change in pH, bicarbonate, or BE. SB therapy was not independently associated with mortality.

Conclusions

ABG-confirmed decompensated metabolic acidosis was rare but associated with a high mortality. SB administration occurred in a minority of patients and in more acidaemic patients. However, SB dose was stereotypical and not tailored to acidosis severity. Assessment of SB effect was infrequent and showed no correction of acidosis. Systematic studies of titrated SB therapy are required to inform current practice.

2023 Update on Sepsis and Septic Shock in Adult Patients: Management in the Emergency Department

BACKGROUND

Sepsis/septic shock is a life-threatening and time-dependent condition that requires timely management to reduce mortality. This review aims to update physicians with regard to the main pillars of treatment for this insidious condition.

METHODS

PubMed, Scopus, and EMBASE were searched from inception with special attention paid to November 2021-January 2023.

RESULTS

The management of sepsis/septic shock is challenging and involves different pathophysiological aspects, encompassing empirical antimicrobial treatment (which is promptly administered after microbial tests), fluid (crystalloids) replacement (to be established according to fluid tolerance and fluid responsiveness), and vasoactive agents (e.g., norepinephrine (NE)), which are employed to maintain mean arterial pressure above 65 mmHg and reduce the risk of fluid overload. In cases of refractory shock, vasopressin (rather than epinephrine) should be combined with NE to reach an acceptable level of pressure control. If mechanical ventilation is indicated, the tidal volume should be reduced from 10 to 6 mL/kg. Heparin is administered to prevent venous thromboembolism, and glycemic control is recommended. The efficacy of other treatments (e.g., proton-pump inhibitors, sodium bicarbonate, etc.) is largely debated, and such treatments might be used on a case-to-case basis.

CONCLUSIONS

The management of sepsis/septic shock has significantly progressed in the last few years. Improving knowledge of the main therapeutic cornerstones of this challenging condition is crucial to achieve better patient outcomes.

Acid-base imbalance as a risk factor for mortality among COVID-19 hospitalized patients

Severe coronavirus disease 2019 (COVID-19) infection can lead to extensive lung infiltrate, a significant increase in the respiratory rate, and respiratory failure, which can affect the acid-base balance. No research in the Middle East has previously examined acid-base imbalance in COVID-19 patients. The present study aimed to describe the acid-base imbalance in hospitalized COVID-19 patients, determine its causes, and assess its impact on mortality in a Jordanian hospital. The study divided patients into 11 groups based on arterial blood gas data. Patients in normal group were defined as having a pH of 7.35-7.45, PaCO2 of 35-45 mmHg, and HCO3- of 21-27 mEq/L. Other patients were divided into 10 additional groups: mixed acidosis and alkalosis, respiratory and metabolic acidosis with or without compensation, and respiratory and metabolic alkalosis with or without compensation. This is the first study to categorize patients in this way. The results showed that acid-base imbalance was a significant risk factor for mortality (P<0.0001). Mixed acidosis nearly quadruples the risk of death when compared with those with normal levels (OR = 3.61, P=0.05). Furthermore, the risk of death was twice as high (OR = 2) for metabolic acidosis with respiratory compensation (P=0.002), respiratory alkalosis with metabolic compensation (P=0.002), or respiratory acidosis with no compensation (P=0.002). In conclusion, acid-base abnormalities, particularly mixed metabolic and respiratory acidosis, were associated with increased mortality in hospitalized COVID-19 patients. Clinicians should be aware of the significance of these abnormalities and address their underlying causes.

Clinical outcome and risk factors for acute fulminant myocarditis supported by venoarterial extracorporeal membrane oxygenation: An analysis of nationwide CSECLS database in China

BACKGROUND

To assess the outcomes and risk factors for adult patients with acute fulminant myocarditis (AFM) supported with venoarterial extracorporeal membrane oxygenation (VA ECMO) in China mainland.

METHODS

Data were extracted from Chinese Society of ExtraCorporeal Life Support (CSECLS) Registry database. Data from adult patients who were diagnosed with AFM and needed VA ECMO in the database were retrospectively analyzed. The primary outcome was 90-day mortality after ECMO initiation in patients with AFM supported with VA ECMO. Cox proportional hazard regression model was used to examine the risk factors associated with 90-day mortality.

RESULTS

Among 221 patients enrolled and followed up to 90 days, 186 (84.2%) patients weaned from ECMO and 159 (71.9%) patients survived and discharged home. The median age was 38 years (IQR 29-49) and males (n = 115) represented 52.0% of the total accounted patients. The median ECMO duration was 134 h (IQR 96-177 h). The main adverse event during ECMO course was bleeding (16.3%), followed by infection (15.4%). In the multivariate Cox model analysis, cardiac arrest prior to ECMO initiation (adjusted HR 2.529; 95%CI: 1.341-4.767, p = 0.004), lower pH value (adjusted HR 0.016; 95%CI: 0.010-0.059, p < 0.001) and higher lactate concentration at 24 h after ECMO initiation (adjusted HR 1.146; 95%CI: 1.075-1.221, p < 0.001) were associated with 90-day mortality.

CONCLUSIONS

71.9% patients with AFM (clinical diagnosed) supported with VA ECMO survived. Cardiac arrest prior to ECMO, lower pH and higher lactate concentration at 24 h after ECMO initiation were correlated with 90-day mortality of AFM patients supported with VA ECMO.

Development of a novel tool: a nomogram for predicting in-hospital mortality of patients in intensive care unit after percutaneous coronary intervention

BACKGROUNDS

Increased risk of in-hospital mortality is critical to guide medical decisions and it played a central role in intensive care unit (ICU) with high risk of in-hospital mortality after primary percutaneous coronary intervention (PCI). At present，most predicting tools for in-hospital mortality after PCI were based on the results of coronary angiography, echocardiography, and laboratory results which are difficult to obtain at admission. The difficulty of using these tools limit their clinical application. This study aimed to develop a clinical prognostic nomogram to predict the in-hospital mortality of patients in ICU after PCI.

METHODS

We extracted data from a public database named the Medical Information Mart for Intensive Care (MIMIC III). Adult patients with coronary artery stent insertion were included. They were divided into two groups according to the primary outcome (death in hospital or survive). All patients were randomly divided into training set and validation set randomly at a ratio of 6:4. Least absolute shrinkage and selection operator (LASSO) regression was performed in the training set to select optimal variables to predict the in-hospital mortality of patients in ICU after PCI. The multivariate logistical analysis was performed to develop a nomogram. Finally, the predictive efficiency of the nomogram was assessed by area under the receiver operating characteristic curve (AUROC)，integrated discrimination improvement (IDI), and net reclassification improvement (NRI), and clinical net benefit was assessed by Decision curve analysis (DCA).

RESULTS

A total of 2160 patients were recruited in this study. By using LASSO, 17 variables were finally included. We used multivariate logistic regression to construct a prediction model which was presented in the form of a nomogram. The calibration plot of the nomogram revealed good fit in the training set and validation set. Compared with the sequential organ failure assessment (SOFA) and scale for the assessment of positive symptoms II (SAPS II) scores, the nomogram exhibited better AUROC of 0.907 (95% confidence interval [CI] was 0.880-0.933, p <  0.001) and 0.901 (95% CI was 0.865-0.936, P <  0.001) in the training set and validation set, respectively. In addition, DCA of the nomogram showed that it could achieve good net benefit in the clinic.

CONCLUSIONS

A new nomogram was constructed, and it presented excellent performance in predicting in-hospital mortality of patients in ICU after PCI.

Long-Term Outcome of Severe Metabolic Acidemia in ICU Patients, a BICAR-ICU Trial Post Hoc Analysis

OBJECTIVES

Long-term prognosis of ICU survivors is a major issue. Severe acidemia upon ICU admission is associated with very high short-term mortality. Since the long-term prognosis of these patients is unknown, we aimed to determine the long-term health-related quality of life and survival of these patients.

DESIGN

Post hoc analysis of a multicenter, randomized, controlled trial.

SETTING

Twenty-six French ICUs.

PATIENTS

Day 28 critically ill survivors admitted with severe acidemia and enrolled in the BICAR-ICU trial.

INTERVENTION

Sodium bicarbonate versus no sodium bicarbonate infusion according to the randomization group.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was health-related quality of life (HRQoL) measured with the 36-item Short Form Health Survey and the EuroQol 5-D questionnaires. Secondary outcomes were mortality, end-stage renal disease treated with renal replacement therapy or renal transplantation, place of residence, professional status, and ICU readmission. HRQoL was reduced with no significant difference between the two groups. HRQoL was reduced particularly in the role-physical health domain (64/100 ± 41 in the control group and 49/100 ± 43 in the bicarbonate group, p = 0.28), but it was conserved in the emotional domains (96/100 ± 19 in the control group and 86/100 ± 34 in the bicarbonate group, p = 0.44). Forty percent of the survivors described moderate to severe problems walking, and half of the survivors described moderate to severe problems dealing with usual activities. Moderate to severe anxiety or depression symptoms were present in one third of the survivors. Compared with the French general population, HRQoL was decreased in the survivors mostly in the physical domains. The 5-year overall survival rate was 30% with no significant difference between groups.

CONCLUSIONS

Long-term HRQoL was decreased in both the control and the sodium bicarbonate groups of the BICAR-ICU trial and was lower than the general population, especially in the physical domains.

Acute Diarrhea and Severe Dehydration in Children: Does Non-anion-gap Component of Severe Metabolic Acidemia Need More Attention?

Background

Despite significant loss of bicarbonate during acute diarrhea, pediatric data are scarce with acute diarrhea/severe dehydration (ADSD) and severe non-anion-gap metabolic acidemia (sNAGMA). We planned to study their clinical profile, critical care needs, and outcome.

Patients

Children (1 month-12 years) with ADSD and sNAGMA (pH <7.2 and/or bicarbonate <15 mEq/L, and normal/mixed anion gap) admitted in Pediatric Emergency Department from January 2016 to December 2018 were enrolled. Children with pure high-anion-gap metabolic acidemia were excluded.

Methods

Medical records were reviewed retrospectively. The primary outcome was time taken to resolve acidemia. Secondary outcomes were acute care area free days in 5 days (ACAFD₅), and adverse outcome as composite of Pediatric Intensive Care Unit (PICU) admission and/or death.

Results

Out of 929 diarrhea patients admitted for intravenous therapy, 121 (13%; median age, 4 months) had ADSD and sNAGMA. Median (IQR) pH was 7.11 (7.01-7.22); 21% patients had pH <7.00. Hyperchloremia (96%) and hypernatremia (45%) were common. About 12% patients each required inotropes and ventilation, while 58% had acute kidney injury (AKI). Median (IQR) time for resolution of acidemia among survivors was 24 (12, 24) hours. Thirty-two patients had adverse outcome. Higher grades of sNAGMA were associated with shock, AKI, coma, hypernatremia, hyperkalemia, adverse outcome, and lesser ACAFD₅. Shock, ventilation, renal replacement therapy (RRT), and higher grades of sNAGMA were predictors of adverse outcome, with former two being independent predictors.

Conclusion

Severe non-anion-gap metabolic acidemia in children with ADSD is associated with organ dysfunctions, dyselectrolytemias, and lesser ACAFD5. Resolution of acidemia took unacceptably longer time. Higher grades of sNAGMA were a predictor of adverse outcomes. Trials are suggested to assess the role of additional bicarbonate therapy.

How to cite this article

Takia L, Baranwal AK, Gupta PK, Angurana SK, Jayashree M. Acute Diarrhea and Severe Dehydration in Children: Does Non-anion-gap Component of Severe Metabolic Acidemia Need More Attention? Indian J Crit Care Med 2022;26(12):1300-1307.

Lactic Acidosis Related to Pharmacotherapy and Human Diseases

Lactic acidosis represents one of the most common conditions that can compromise the health of intensive care unit (ICU) patients, increasing the mortality of patients with high levels of Lactate who do not receive a proper treatment within the first 6 h of hospitalization. There are two enantiomers of lactic acid: L-lactic acid (when the concentration increases, it can lead to a state of severe acidemia risking cardiovascular collapse, causing an increase in mortality in ICU patients) and D lactic acid (produced in the human organism by microbiota and its production increases during some pathological status). Generally, increased levels of serum lactic acid could be due to numerous factors, including hypoxia (caused for example by septic/cardiogenic/hypovolemic or obstructive shock), specific pathologies (e.g., liver disease), use of some drugs (e.g., metformin), presence of toxins, and trauma. Since the underlying cause could be fatal for the ICU patient, it is important to understand the root of this clinical status with a view to correct it and prevent the risk of a poor clinical outcome. Prevention and early treatment are the keys to control the negative clinical consequences. The aim of this review is to revise the scientific literature for further confirmation about the importance of early identification of acidotic statuses and to underline how an early diagnosis can prevent the worst clinical outcome, especially for ICU patients who are more fragile compared to the general population.

Establishment and external validation of an online dynamic nomogram for predicting in-hospital death risk in sepsis-associated acute kidney disease

OBJECTIVES

Approximately one-third of patients with sepsis-associated acute kidney injury (AKI) progress to acute kidney disease (AKD) with higher short-term mortality. We aimed to identify the clinical characteristics that influence in-hospital death in sepsis-associated AKD and develop a nomogram to facilitate early warning.

METHODS

Logical regression was applied to screen variables based on clinical data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. A nomogram was established to predict in-hospital death risk in patients with sepsis-associated AKD. The eICU Collaborative Research Database (eICU-CRD) was used for external validation. The receiver operating characteristic and calibration curves were used to determine the model's performance.

RESULTS

A total of 1,779 patients with sepsis-associated AKD were included from the MIMIC-IV and 344 from the eICU-CRD. Age, Glasgow coma scale score, systolic blood pressure, peripheral oxygen saturation, platelet count, white blood cell count, and bicarbonate levels were significantly correlated with death. The nomogram demonstrated high discrimination in the training (C-index, 0.829; 95% confidence interval [CI] [0.807-0.852]) and testing sets (C-index: 0.760; 95% CI [0.706-0.814]). At the optimal cut-off value of 0.270, the model's sensitivity in the training and validation datasets was 72.8% (95% CI [68.3-76.9%]) and 64.5% (95% CI [54.9-73.4%]), while the specificity was 79.2% (95% CI [76.9-81.4%]) and 74.8% (95% CI [68.7-80.2%]), respectively.

CONCLUSION

We identified seven predictors of in-hospital death in patients with sepsis-associated AKD. In addition, we developed an online dynamic nomogram to accurately and conveniently predict short-term outcomes, which performed well in the external dataset.

Interplay of carbon dioxide and peroxide metabolism in mammalian cells

The carbon dioxide/bicarbonate (CO₂/HCO₃^-) molecular pair is ubiquitous in mammalian cells and tissues, mainly as a result of oxidative decarboxylation reactions that occur during intermediary metabolism. CO₂ is in rapid equilibrium with HCO₃^-via the hydration reaction catalyzed by carbonic anhydrases. Far from being an inert compound in redox biology, CO₂ enhances or redirects the reactivity of peroxides, modulating the velocity, extent, and type of one- and two-electron oxidation reactions mediated by hydrogen peroxide (H₂O₂) and peroxynitrite (ONOO^-/ONOOH). Herein, we review the biochemical mechanisms by which CO₂ engages in peroxide-dependent reactions, free radical production, redox signaling, and oxidative damage. First, we cover the metabolic formation of CO₂ and its connection to peroxide formation and decomposition. Next, the reaction mechanisms, kinetics, and processes by which the CO₂/peroxide interplay modulates mammalian cell redox biology are scrutinized in-depth. Importantly, CO₂ also regulates gene expression related to redox and nitric oxide metabolism and as such influences oxidative and inflammatory processes. Accumulated biochemical evidence in vitro, in cellula, and in vivo unambiguously show that the CO₂ and peroxide metabolic pathways are intertwined and together participate in key redox events in mammalian cells.

Inappropriate Ventilatory Homeostatic Responses in Hospitalized COVID-19 Patients

Background

The clinical presentation of COVID-19 suggests altered breathing control - tachypnoea, relative lack of dyspnoea, and often a discrepancy between severity of clinical and radiological findings. Few studies characterize and analyse the contribution of breathing drivers and their ventilatory and perceptual responses.

Aim

To establish the prevalence of inappropriate ventilatory and perceptual response in COVID-19, by characterizing the relationships between respiratory rate (RR), dyspnoea and arterial blood gas (ABG) in a cohort of COVID-19 patients at presentation to hospital, and their post-Covid respiratory sequelae at follow-up.

Methods

We conducted a retrospective cohort study including consecutive adult patients admitted to hospital with confirmed COVID-19 between 1st March 2020 and 30th April 2020. In those with concurrent ABG, RR and documented dyspnoea status on presentation, we documented patient characteristics, disease severity, and outcomes at hospital and 6-week post-discharge.

Results

Of 492 admissions, 194 patients met the inclusion criteria. Tachypnoea was present in 75% pronounced (RR>30) in 36%, and persisted during sleep. RR correlated with heart rate (HR) (r = 0.2674), temperature (r = 0.2824), CRP (r = 0.2561), Alveolar-arterial (A-a) gradient (r = 0.4189), and lower PaO₂/FiO₂ (PF) ratio (r = −0.3636). RR was not correlated with any neurological symptoms. Dyspnoea was correlated with RR (r = 0.2932), A-a gradient (r = 0.1723), and lower PF ratio (r = −0.1914), but not correlated with PaO₂ (r = −0.1095), PaCO₂ (r = −0.0598) or any recorded neurological symptom except for altered consciousness. Impaired ventilatory homeostatic control of pH/PaCO₂ [tachypnoea (RR>20), hypocapnia (PaCO₂ <4.6 kPa), and alkalosis (pH>7.45)] was observed in 29%. This group, of which 37% reported no dyspnoea, had more severe respiratory disease (A-a gradient 38.9 vs. 12.4 mmHg; PF ratio 120 vs. 238), and higher prevalence of anosmia (21 vs. 15%), dysgeusia (25 vs. 12%), headache (33 vs. 23%) and nausea (33 vs. 14%) with similar rates of new anxiety/depression (26 vs. 23%), but lower incidence of past neurological or psychiatric diagnoses (5 vs. 21%) compared to appropriate responders. Only 5% had hypoxia sufficiently severe to drive breathing (i.e. PaO₂ <6.6 kPa). At 6 weeks post-discharge, 24% (8/34) showed a new breathing pattern disorder with no other neurological findings, nor previous respiratory, neurological, or psychiatric disorder diagnoses.

Conclusions

Impaired homeostatic control of ventilation i.e., tachypnoea, despite hypocapnia to the point of alkalosis appears prevalent in patients admitted to hospital with COVID-19, a finding typically accompanying more severe disease. Tachypnoea prevalence was between 12 and 29%. Data suggest that excessive tachypnoea is driven by both peripheral and central mechanisms, but not hypoxia. Over a third of patients with impaired homeostatic ventilatory control did not experience dyspnoea despite tachypnoea. A subset of followed-up patients developed post-covid breathing pattern disorder.

Effect of sodium bicarbonate on functional outcome in patients with out-of-hospital cardiac arrest: a post-hoc analysis of a French and North-American dataset

BACKGROUND AND IMPORTANCE

No large randomised controlled trial has assessed the potential benefits on neurologic outcomes of prehospital sodium bicarbonate administration in patients with nontraumatic out-of-hospital cardiac arrest (OHCA).

OBJECTIVE

To obtain information of assistance in designing a randomised controlled trial of bicarbonate therapy after OHCA in specific patient subgroups.

DESIGN

We conducted two, separate, simultaneous, retrospective studies of two distinct, unlinked datasets.

SETTING AND PARTICIPANTS

One dataset was a French nationwide population-based registry (RéAC Registry, French dataset) and the other was a randomised controlled trial comparing continuous to interrupted chest compressions in North America (ROC-CCC trial, North-American dataset).

INTERVENTION

We investigated whether prehospital bicarbonate administration was associated with better neurologic outcomes.

OUTCOME MEASURES AND ANALYSES

The main outcome measure was the functional outcome at hospital discharge. To adjust for potential confounders, we conducted a nested propensity-score-matched analysis with inverse probability-of-treatment weighting.

MAIN RESULTS

In the French dataset, of the 54 807 patients, 1234 (2.2%) received sodium bicarbonate and 450 were matched. After propensity-score matching, sodium bicarbonate was not associated with a higher likelihood of favourable functional outcomes on day 30 [adjusted odds ratio (aOR), 0.912; 95% confidence interval (95%CI), 0.501-1.655]. In the North-American dataset, of the 23 711 included patients, 4902 (20.6%) received sodium bicarbonate and 1238 were matched. After propensity-score matching, sodium bicarbonate was associated with a lower likelihood of favourable functional outcomes at hospital discharge (aOR, 0.45; 95% CI, 0.34-0.58).

CONCLUSION

In patients with OHCA, prehospital sodium bicarbonate administration was not associated with neurologic outcomes in a French dataset and was associated with worse neurologic outcomes in a North-American dataset. Given the considerable variability in sodium bicarbonate use by different prehospital care systems and the potential resuscitation-time bias in the present study, a large randomised clinical trial targeting specific patient subgroups may be needed to determine whether sodium bicarbonate has a role in the prehospital management of prolonged OHCA.

Acid-Base Disorders in COVID-19 Patients with Acute Respiratory Distress Syndrome

Our aim was to investigate the distribution of acid-base disorders in patients with COVID-19 ARDS using both the Henderson–Hasselbalch and Stewart’s approach and to explore if hypoxemia can influence acid-base disorders. COVID-19 ARDS patients, within the first 48 h of the need for a non-invasive respiratory support, were retrospectively enrolled. Respiratory support was provided by helmet continuous positive airway pressure (CPAP) or by non-invasive ventilation. One hundred and four patients were enrolled, 84% treated with CPAP and 16% with non-invasive ventilation. Using the Henderson–Hasselbalch approach, 40% and 32% of patients presented respiratory and metabolic alkalosis, respectively; 13% did not present acid-base disorders. Using Stewart’s approach, 43% and 33% had a respiratory and metabolic alkalosis, respectively; 12% of patients had a mixed disorder characterized by normal pH with a lower SID. The severe hypoxemic and moderate hypoxemic group presented similar frequencies of respiratory and metabolic alkalosis. The most frequent acid-base disorders were respiratory and metabolic alkalosis using both the Henderson–Hasselbalch and Stewart’s approach. Stewart’s approach detected mixed disorders with a normal pH probably generated by the combined effect of strong ions and weak acids. The impairment of oxygenation did not affect acid-base disorders.

Clinical outcomes of Indigenous Australians and New Zealand Māori with metabolic acidosis and acidaemia

Objective: To assess the incidence and impact of metabolic acidosis in Indigenous and non-Indigenous patients Design: Retrospective study. Setting: Adult intensive care units (ICUs) from Australia and New Zealand. Participants: Patients aged 16 years or older admitted to an Australian or New Zealand ICU in one of 195 contributing ICUs between January 2019 and December 2020 who had metabolic acidosis, defined as pH < 7.30, base excess (BE) < -4 mEq/L and PaCO2 ≤ 45 mmHg. Main outcome measures: The primary outcome was the prevalence of metabolic acidosis. Secondary outcomes included ICU length of stay, hospital length of stay, receipt of renal replacement therapy (RRT), major adverse kidney events at 30 days (MAKE30), and hospital mortality. Results: Overall, 248 563 patients underwent analysis, with 11 537 (4.6%) in the Indigenous group and 237 026 (95.4%) in the non-Indigenous group. The prevalence of metabolic acidosis was higher in Indigenous patients (9.3% v 6.1%; P < 0.001). Indigenous patients with metabolic acidosis received RRT more often (28.2% v 22.0%; P < 0.001), but hospital mortality was similar between the groups (25.8% in Indigenous v 25.8% in non-Indigenous; P = 0.971). Conclusions: Critically ill Indigenous ICU patients are more likely to have a metabolic acidosis in the first 24 hours of their ICU admission, and more often received RRT during their ICU admission compared with non-Indigenous patients. However, hospital mortality was similar between the groups.

Refractory Hyperlactatemia and Hypoglycemia in an Adult with Non-Hodgkin's Lymphoma: A Case Report and Review of the Warburg Effect

Lactate is a byproduct of anaerobic glycolysis, and hyperlactatemia is commonly seen in critically ill patients. We report a case of an elderly male presenting with undifferentiated constitutional symptoms, anemia, thrombocytopenia, severe lactic acidosis, refractory hypoglycemia, and a newly detected abdominal mass. A dedicated workup ruled out infectious etiologies and revealed metastatic non-Hodgkin's lymphoma. This study explores etiologies of type B lactic acidosis in oncology patients, with a focus on Warburg's effect, and its potential for prognostication.

Management of acute metabolic acidosis in the ICU: sodium bicarbonate and renal replacement therapy

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2021. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2021 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Systemic acidemia impairs cardiac function in critically Ill patients

BACKGROUND

Acidemia, is associated with reduced cardiac function in animals, but no studies showing an effect of acidemia on cardiac function in humans are reported. In the present study, we examined the effect of acidemia on cardiac function assessed with transpulmonary thermodilution technique with integrated pulse contour analysis (Pulse Contour Cardiac Output, PiCCO™) in a large cohort of critically ill patients.

METHODS

This was a prospective multicenter observational cross-sectional study of 297 patients from 6 intensive care units in London, England selected from all patients admitted consecutively between May 2018 and March 2019. Measurements of lowest plasma pH and concurrent assessment of cardiac function were obtained.

FINDINGS

There was a significant difference between two pH categories (pH ≤ 7.28 vs. pH > 7.28) for the following variables of cardiac function: SVI (difference in means 32.7; 95% CI: 21 to 45 mL/m2; p < 0.001); GEF (18; 95% CI: 11 to 26%; p < 0.001), dPmax (-331; 95% CI: -510 to -153 mmHg/s; p = 0.001), CFI (0.7; 95% CI: 0.2 to 1.3 1/min; p = 0.01) and CPI (0.09; 95% CI: 0.03 to 0.15 W/m2; p < 0.001). However, there was no significant difference in CI (0.13; 95% CI: -0.20 to 0.47 L/min/m2; p = 0.12) between the pH categories. Also, a significant relationship was found between the quantitative pH and the following variables: SVI (132; 95% CI: 77 to 188 mL/m2; p < 0.001), GEF (74.7; 95% CI: 37.1 to 112.4%; p < 0.001), dPmax (-1587; 95% CI: -2361 to -815 mmHg/s; p < 0.001), CFI (3.5; 95% CI: 0.9 to 6.1 /min; p = 0.009), CPI (0.62; 95% CI: 0.36 to 0.88 W/m2; p < 0.001) and CI (regression coefficient 1.96; 95% CI:0.45 to 3.47 L/min/m2; p = 0.01).

INTERPRETATION

Acidemia is associated with impaired cardiac function in seriously ill patients hospitalized in the intensive care unit supporting the potential value of early diagnosis and improvement of arterial pH in these patients.

FUNDING

The study was partially supported by unrestricted funds from the UCLA School of Medicine.

Bicarbonate Therapy in Renally Compromised Critically Ill Patients with Metabolic Acidosis: Study of Clinical Outcomes and Mortality Rate

Background

Metabolic acidosis is the most frequent medical condition occurring in critically ill renally compromised patients. This study was aimed to determine clinical outcomes of bicarbonate therapy in renally compromised critically ill patients having metabolic acidosis.

Methods

A prospective longitudinal cohort study was undertaken in three military hospitals in Rawalpindi, Pakistan. All patients fulfilling the inclusion criteria who were admitted to the ICU of any of the three study hospitals from July 2019 to March 2020 were studied for clinical outcomes of bicarbonate therapy using an evidence-based clinical checklist. Outcome measures include changes in blood pH, serum potassium, and sodium levels, blood pressure and weight, along with other clinically significant laboratory parameters.

Results

Eighty-one patients fulfilling the inclusion criteria were evaluated. The mean age of the patients was 55.61±19.5 years, while the mean weight was 63.43±14.19 Kg. A mortality rate of 45.7% was observed. Disease-related complications including hypoxia, cardiac failure, multiple organ failure, elevated blood pressure, and ischemic heart disease (IHD) were found to be associated with a higher mortality rate (P<0.005). Whereas using Fisher’s exact test, concomitant administration of sodium chloride, along with bicarbonate therapy was associated with a low mortality rate and had no significant impact on sodium loading or weight gain. Moreover, various drug–drug interactions were found to be associated with a higher mortality rate (P<0.05).

Conclusion

Bicarbonate therapy was not found to affect the mortality rate in critically ill renally compromised patients with metabolic acidosis.

Lactic Acidosis and the Role of Sodium Bicarbonate: A Narrative Opinion

Lactic acidosis occurs commonly and can be a marker of significant physiologic derangements. However what an elevated lactate level and acidemia connotes and what should be done about it is subject to inconsistent interpretations. This review examines the varied etiologies of lactic acidosis, the physiologic consequences, and the known effects of its treatment with sodium bicarbonate. Lactic acidosis is often assumed to be a marker of hypoperfusion, but it can also result from medications, organ dysfunction, and sepsis even in the absence of malperfusion. Acidemia causes deleterious effects in almost every organ system, but it can also have positive effects, increasing localized blood flow and oxygen delivery, as well as providing protection against hypoxic cellular injury. The use of sodium bicarbonate to correct severe acidemia may be tempting to clinicians, but previous studies have failed to show improved patient outcomes following bicarbonate administration. Bicarbonate use is known to decrease vasomotor tone, decrease myocardial contractility, and induce intracellular acidosis. This suggests that mild to moderate acidemia does not require correction. Most recently, a randomized control trial found a survival benefit in a subgroup of critically ill patients with serum pH levels <7.2 with concomitant acute kidney injury. There is no known benefit of correcting serum pH levels ≥ 7.2, and sparse evidence supports bicarbonate use <7.2. If administered, bicarbonate is best given as a slow IV infusion in the setting of adequate ventilation and calcium replacement to mitigate its untoward effects.

Acid base disorders in patients with COVID-19

Purpose

Acid–base derangement has been poorly described in patients with coronavirus disease 2019 (COVID-19). Considering the high prevalence of pneumonia and kidneys injury in COVID-19, frequent acid–base alterations are expected in patients admitted with SARS-Cov-2 infection. The study aimed to assess the prevalence of acid–base disorders in symptomatic patients with a diagnosis of COVID-19.

Methods

The retrospective study enrolled COVID-19 patients hospitalized at the University Hospital of Modena from 4 March to 20 June 2020. Baseline arterial blood gas (ABG) analysis was collected in 211 patients. In subjects with multiple ABG analysis, we selected only the first measurement. A pH of less than 7.37 was categorized as acidemia and a pH of more than 7.43 was categorized as alkalemia.

Results

ABG analyses revealed a low arterial partial pressure of oxygen (PO₂, 70.2 ± 25.1 mmHg), oxygen saturation (SO₂, 92%) and a mild reduction of PO₂/FiO₂ ratio (231 ± 129). Acid–base alterations were found in 79.7% of the patient. Metabolic alkalosis (33.6%) was the main alteration followed by respiratory alkalosis (30.3%), combined alkalosis (9.4%), respiratory acidosis (3.3%), metabolic acidosis (2.8%) and other compensated acid–base disturbances (3.6%). All six patients with metabolic acidosis died at the end of the follow-up.

Conclusion

Variations of pH occurred in the majority (79.7%) of patients admitted with COVID-19. The patients experienced all the type of acid–base disorders, notably metabolic and respiratory alkalosis were the most common alterations in this group of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-021-02855-1.

Effects of sodium bicarbonate infusion on mortality in medical-surgical ICU patients with metabolic acidosis-A single-center propensity score matched analysis

OBJECTIVE

Metabolic acidosis is associated with high mortality. Despite theoretical benefits of sodium-bicarbonate (SB), current evidence remains controversial. We investigated SB-related effects on outcomes in ICU patients with metabolic acidosis.

DESIGN

Retrospective analysis.

SETTING

Academic medical center.

PATIENTS OR PARTICIPANTS

971 ICU patients with metabolic acidosis defined as arterial pH<7.3 and CO2<45mmHg treated between 2012 and 2016. A propensity score (PS) was estimated using logistic regression. Patients were matched in pairs using the PS.

INTERVENTIONS

441 patients were treated with SB 8.4% (SB-group) and n=530 patients were not (control group).

MAIN VARIABLES OF INTEREST

Primary outcome was all-cause mortality at ICU-discharge. Average Treatment Effect (ATE), Average Treatment effect in Treated (ATT), and estimated relative survival effects at 20 days were computed.

RESULTS

In the full cohort, we observed considerable differences in pH, base excess, additional acidosis-related indices, and ICU mortality (controls 31% vs. SB-group 56%, p<.001) at baseline between the two groups. After PS-matching (n=174 in each group), no significant difference in ICU mortality was observed (controls 32% vs. SB-group 41%; p=.07). Odds ratios (OR) for ATE and ATT showed no association with ICU mortality (OR ATE: 1.08, 95%-CI 0.99-1.17; p=.08; OR ATT 1.09; 95%-CI 0.99-1.2; p=.09). Hazard ratios at 20-days (multivariable HR, matched sample n=348: 1.16, 95%-CI 0.86-1.56, p=.33) showed similar survival in the two study groups.

CONCLUSIONS

We did not observe effects of SB infusion on all-cause mortality in critically ill patients with metabolic acidosis.

Admission Anion Gap Metabolic Acidosis and Its Impact on Patients in Medical Intensive Care Unit

Introduction  Anion gap (AG) metabolic acidosis is common in critically ill patients. The relationship between initial AG at the time of admission to the medical intensive care unit (MICU) and mortality or length of stay is unclear. This study was undertaken to evaluate this relationship. Materials and Method  We prospectively examined the acid-base status of 500 consecutive patients at the time of MICU admission and outcome was measured in terms of mortality, length of ICU stay, need of ventilator, and laboratory parameters. The patients were divided into four stages based on the severity of AG. Outcome based on the severity of AG was measured, and comparisons that adjusted for baseline characteristics were performed. Results  This study showed that increased AG was associated with the higher mortality. Patients with the highest AG also had the longest length of stay in the MICU, and patients with normal acid-base status had the shortest ICU length of stays ( p < 0.05). Conclusion  A high AG at the time of admission to the MICU was associated with higher mortality and length of stays. Initial risk stratification based on AG and metabolic acidosis may help guide appropriate patient disposition (especially in patients without other definitive criteria for MICU admission) and assist with prognosis.

Balanced crystalloids versus saline in critically ill adults with low plasma bicarbonate: A secondary analysis of a clinical trial

PURPOSE

We aimed to determine if balanced crystalloids compared with saline improve outcomes in critically ill adults admitted with low plasma bicarbonate.

MATERIALS AND METHODS

We performed a secondary analysis of the Isotonic Solutions and Major Adverse Renal Events Trial (SMART). We included patients who presented to the Emergency Department with a first measured plasma bicarbonate less than 20 mmol/L. Among these patients, we compared the effect of balanced crystalloid versus saline on the primary outcome of major adverse kidney events within 30 days (MAKE30), defined as a composite of death, new renal-replacement therapy, or persistent renal dysfunction (final inpatient creatinine ≥200% baseline). Secondary outcomes included 30 day in-hospital mortality, receipt of new RRT, persistent renal dysfunction, incident AKI, and vasopressor-free days.

RESULTS

Among the 2029 patients with an initial plasma bicarbonate concentration < 20 mmol/L, there was no difference in the incidence of MAKE30 between those assigned to balanced crystalloid versus saline (21.8% vs 21.3%; P = 0.93). Secondary outcomes were similar between the balanced crystalloid and saline groups.

CONCLUSIONS

Among critically ill adults presenting to the Emergency Department, initial plasma bicarbonate concentration does not appear to be a useful marker to guide the selection of balanced crystalloid versus saline.

Sodium Bicarbonate in Different Critically Ill Conditions: From Physiology to Clinical Practice

Intravenous sodium bicarbonate is commonly used in several critically ill conditions for the management of acute acidemia independently of the etiology, and for the prevention of acute kidney injury, although this is still controversial from a physiologic point of view.

New Trends in the Utilization of Intravenous Fluids

Intravenous fluids (IVFs) are the most commonly used drugs in hospitalized patients. Knowledge of the indications and pharmacokinetics of IVFs is critical for all medical disciplines. Isotonic saline (normal saline, 0.9% NS) is the most utilized intravenous solution. Isotonic saline effectively expands the intravascular compartment, as one-quarter of the infusate goes intravascularly, while the remaining three-quarters go into the interstitial space. The proper use of IVFs in different clinical scenarios is paramount. IVFs differ with regard to their half-life, intravascular volume expansion, preparation, and cost. Crystalloids are more commonly utilized due to their relatively low cost and availability. Colloids are very advantageous in cases of shock or hemorrhage, as they remain in the intravascular space, thus facilitating an increase in blood pressure (BP) prior to blood administration. Colloids are also advantageous in cases of burns and severe hypoglobulinemia. Human albumin (5%, 20%, and 25%) is the most used colloid solution. It remains intravascularly provided and there is no capillary leak as in systematic inflammation. The goal in hospitalized patients is timely and adequate intravenous fluid resuscitation. Utilization of a large volume of isotonic saline may lead to hypervolemia, hypernatremia, hyperchloremia, metabolic acidosis, and hypokalemia. The use of balanced intravenous solutions has been advocated to avoid these complications.

Temporal inversion of the acid-base equilibrium in newborns: an observational study

Background

A considerable fraction of newborn infants experience hypoxia-ischaemia and metabolic acidosis at birth. However, little is known regarding the biological response of newborn infants to the pH drift from the physiological equilibrium. The aim of this study was to investigate the relationship between the pH drift at birth and postnatal acid-base regulation in newborn infants.

Methods

Clinical information of 200 spontaneously breathing newborn infants hospitalised at a neonatal intensive care centre were reviewed. Clinical variables associated with venous blood pH on days 5-7 were assessed.

Results

The higher blood pH on days 5-7 were explained by lower cord blood pH (-0.131, -0.210 to -0.052; regression coefficient, 95% confidence interval), greater gestational age (0.004, 0.002 to 0.005) and lower partial pressure of carbon dioxide on days 5-7 (-0.005, -0.006 to -0.004) (adjusted for sex, postnatal age and lactate on days 5-7).

Conclusion

In relatively stable newborn infants, blood pH drift from the physiological equilibrium at birth might trigger a system, which reverts and over-corrects blood pH within the first week of life. Given that the infants within the study cohort was spontaneously breathing, the observed phenomenon might be a common reaction of newborn infants to pH changes at birth.

The prognostic value of early lactate clearance for survival after out-of-hospital cardiac arrest

BACKGROUND

Prognostication of survival after out-of-hospital cardiac arrest (OHCA) remains challenging with current guidelines recommending the prognostication no earlier than 72 h after return of spontaneous circulation (ROSC). Prognostic factors that could be used earlier after ROSC, like lactate clearance, are still being studied.

OBJECTIVES

This paper aims to investigate the prognostic strength of early lactate clearance for survival after OHCA.

METHODS

This retrospective observational single-center study focuses on patients for whom ROSC was achieved after OHCA. Patients ≥18 years admitted between September 2012 and January 2019, for which arterial serum lactate measurements were available immediately at and 3 h after hospital admission (T0 and T3), were included.

RESULTS

192 patients were included. Lactate clearance at T3 (p < 0.001) was identified as an independent predictor for 24 h, 48 h and 72 h survival. Witnessed arrest, bystander CPR and initial shockable rhythm were independent significant predictors for long term survival after ROSC (1 month, 3 months and 1 year; p < 0.05), but not for 24 h survival. Age (above or below 65 years) was not significant for predicting survival. Upon combination of witnessed arrest, bystander CPR and initial shockable rhythm in a multivariate logistic regression model for long term survival, the initial rhythm was the dominant factor in the combined model, making witnessed arrest and bystander CPR redundant.

CONCLUSION

Lactate clearance at T3 after ROSC is associated with 24 h, 48 h and 72 h survival. Further research is needed to determine how to incorporate lactate clearance as part of a clinically useful tool to predict long term survival.

Early metabolic acidosis in critically ill patients: a binational multicentre study

Objective: We aimed to measure the incidence, prevalence, characteristics and outcomes of intensive care unit (ICU) patients with early (first 24 hours) metabolic acidosis (MA) according to two different levels of severity with a focus on recent data. Design: We retrospectively applied two diagnostic criteria to our analysis based on literature for early MA: i) severe MA criteria (pH ≤ 7.20 and Paco2 ≤ 45 mmHg and HCO3- ≤ 20 mmol/L with total Sequential Organ Failure Assessment [SOFA] score ≥ 4 or lactate ≥ 2 mmol/L), and ii) moderate MA criteria (pH < 7.30 and base excess < -4 mmol/L and Paco2 ≤ 45 mmHg). Setting: ICUs in the Australian and New Zealand Intensive Care Society Adult Patient Database program. Participants: Adult patients registered to the database from 2008 to 2018. Main outcome measures: Incidence, prevalence, and hospital mortality of patients with MA by the two criteria. Results: We screened 1 076 087 patients. Given the Australian and New Zealand population during the study period, we estimated the incidence of severe MA at 39.5 per million per year versus 349.2-411.5 per million per year for moderate MA. In the most recent 2 years, we observed early severe MA in 1.5% (1350/87 110) of patients compared with 8.4% (20 679/244 740) for moderate MA. Overall, hospital mortality for patients with early severe MA was 48.3% (652/1350) compared with 21.5% (4444/20 679) for moderate MA. Conclusions: Early severe MA is uncommon in Australian and New Zealand ICUs and carries a very high mortality. Moderate MA is over seven-fold more common and still carries a high mortality.

Acidemia subtypes in critically ill patients: An international cohort study

PURPOSE

To study the prevalence, characteristic, outcome, and acid-base biomarker predictors of outcome for different acidemia subtypes.

METHODS

We used national intensive care databases from three countries and classified acidemia subtypes as metabolic (standard base excess [SBE] < -2 mEq/L only), respiratory (PaCO₂ > 42 mmHg only), and combined (both SBE < -2 mEq/L and PaCO₂ > 42 mmHg) based on blood gas analysis in the first 24 h after ICU admission. To investigate acid-base predictors for hospital mortality, we applied the area under the receiver operating characteristic curve approach.

RESULTS

We screened 643,689 ICU patients (2014-2018) and detected acidemia in 57.8%. The most common subtype was metabolic (42.9%), followed by combined (30.3%) and respiratory (25.9%). Combined acidemia had a mortality of 12.7%, compared with 11% for metabolic and 5.5% for respiratory. For combined acidemia, the best predictor of hospital mortality was pH. However, for metabolic or respiratory acidemia, it was SBE or PaCO₂, respectively.

CONCLUSIONS

In ICU patients with acidemia, mortality differs according to subtype and is highest in the combined subtype. Best acid-base predictors of mortality also differ according to subtype with best performance for pH in combined, SBE in metabolic, and PaCO₂ in respiratory acidemia.

Registry on extracorporeal multiple organ support with the advanced organ support (ADVOS) system: 2-year interim analysis

The objective of this registry is to collect data on real-life treatment conditions for patients for whom multiple organ dialysis with Advanced Organ Support (ADVOS) albumin hemodialysis is indicated.This registry was performed under routine conditions and without any study-specific intervention, diagnostic procedures, or assessments. Data on clinical laboratory tests, health status, liver function, vital signs, and examinations were collected (DRKS-ID: DRKS00017068). Mortality rates 28 and 90 days after the first ADVOS treatment, adverse events and ADVOS treatment parameters, including treatment abortions, were documented.This analysis was performed 2 years after the first patient was included on January 18, 2017. As of February 20, 2019, 4 clinical sites in Germany participated and enrolled 118 patients with a median age of 60 (IQR: 45, 69) of whom 70 were male (59.3%). Patients had a median SOFA Score of 14 (IQR: 11, 16) and a predicted mortality of 80%. The median number of failing organs was 3 (IQR: 2, 4).Four hundred twenty nine ADVOS treatments sessions were performed with a median duration of 17 hours (IQR: 6, 23). A 5.8% of the ADVOS sessions (25 of 429) were aborted due to device related errors, while 14.5% (62 of 429) were stopped for other reasons. Seventy nine adverse events were documented, 13 of them device related (all clotting, and all recovered without sequels).A significant reduction in serum creatinine (1.5 vs 1.2 mg/dl), blood urea nitrogen (24 vs 17 mg/dl) and bilirubin (6.9 vs 6.5 mg/dl) was observed following the first ADVOS treatment session. Blood pH, bicarbonate (HCO3-) and base excess returned to the physiological range, while partial pressure of carbon dioxide (pCO2) remained unchanged. At the time of the analysis, 28- and 90-day mortality were 60% and 65%, respectively, compared to an expected ICU-mortality rate of 80%. SOFA score was an independent predictor for outcome in a multivariable logistic regression analysis.The reported data show a high quality and completion of all participating centers. Data interpretation must be cautious due to the small number of patients, and the nature of the registry, without a control group. However, the data presented here show an improvement of expected mortality rates. Minor clotting events similar to other dialysis therapies occurred during the treatments.

Incidence and management of metabolic acidosis with sodium bicarbonate in the ICU: An international observational study

BACKGROUND

Metabolic acidosis is a major complication of critical illness. However, its current epidemiology and its treatment with sodium bicarbonate given to correct metabolic acidosis in the ICU are poorly understood.

METHOD

This was an international retrospective observational study in 18 ICUs in Australia, Japan, and Taiwan. Adult patients were consecutively screened, and those with early metabolic acidosis (pH < 7.3 and a Base Excess < -4 mEq/L, within 24-h of ICU admission) were included. Screening continued until 10 patients who received and 10 patients who did not receive sodium bicarbonate in the first 24 h (early bicarbonate therapy) were included at each site. The primary outcome was ICU mortality, and the association between sodium bicarbonate and the clinical outcomes were assessed using regression analysis with generalized linear mixed model.

RESULTS

We screened 9437 patients. Of these, 1292 had early metabolic acidosis (14.0%). Early sodium bicarbonate was given to 18.0% (233/1292) of these patients. Dosing, physiological, and clinical outcome data were assessed in 360 patients. The median dose of sodium bicarbonate in the first 24 h was 110 mmol, which was not correlated with bodyweight or the severity of metabolic acidosis. Patients who received early sodium bicarbonate had higher APACHE III scores, lower pH, lower base excess, lower PaCO₂, and a higher lactate and received higher doses of vasopressors. After adjusting for confounders, the early administration of sodium bicarbonate was associated with an adjusted odds ratio (aOR) of 0.85 (95% CI, 0.44 to 1.62) for ICU mortality. In patients with vasopressor dependency, early sodium bicarbonate was associated with higher mean arterial pressure at 6 h and an aOR of 0.52 (95% CI, 0.22 to 1.19) for ICU mortality.

CONCLUSIONS

Early metabolic acidosis is common in critically ill patients. Early sodium bicarbonate is administered by clinicians to more severely ill patients but without correction for weight or acidosis severity. Bicarbonate therapy in acidotic vasopressor-dependent patients may be beneficial and warrants further investigation.

Changes in NAD and Lipid Metabolism Drive Acidosis-Induced Acute Kidney Injury

BACKGROUND

The kidney plays an important role in maintaining normal blood pH. Metabolic acidosis (MA) upregulates the pathway that mitochondria in the proximal tubule (PT) use to produce ammonia and bicarbonate from glutamine, and is associated with AKI. However, the extent to which MA causes AKI, and thus whether treating MA would be beneficial, is unclear.

METHODS

Gavage with ammonium chloride induced acute MA. Multiphoton imaging of mitochondria (NADH/membrane potential) and transport function (dextran/albumin uptake), oxygen consumption rate (OCR) measurements in isolated tubules, histologic analysis, and electron microscopy in fixed tissue, and urinary biomarkers (KIM-1/clara cell 16) assessed tubular cell structure and function in mouse kidney cortex.

RESULTS

MA induces an acute change in NAD redox state (toward oxidation) in PT mitochondria, without changing the mitochondrial energization state. This change is associated with a switch toward complex I activity and decreased maximal OCR, and a major alteration in normal lipid metabolism, resulting in marked lipid accumulation in PTs and the formation of large multilamellar bodies. These changes, in turn, lead to acute tubular damage and a severe defect in solute uptake. Increasing blood pH with intravenous bicarbonate substantially improves tubular function, whereas preinjection with the NAD precursor nicotinamide (NAM) is highly protective.

CONCLUSIONS

MA induces AKI via changes in PT NAD and lipid metabolism, which can be reversed or prevented by treatment strategies that are viable in humans. These findings might also help to explain why MA accelerates decline in function in CKD.

Risk Potential for Organ Dysfunction Associated With Sodium Bicarbonate Therapy in Critically Ill Patients With Hemodynamic Worsening

Background: The role of sodium bicarbonate therapy (SBT) remains controversial. This study aimed to investigate whether hemodynamic status before SBT contributed to the heterogeneous outcomes associated with SBT in acute critically ill patients. Methods: We obtained data from patients with metabolic acidosis from the Medical Information Mart for Intensive Care (MIMIC)-III database. Propensity score matching (PSM) was applied to match the SBT group with the control group. Logistic regression and Cox regression were used to analyze a composite of newly "developed or exacerbated organ dysfunction" (d/eOD) within 7 days of ICU admission and 28-day mortality associated with SBT for metabolic acidosis. Results: A total of 1,765 patients with metabolic acidosis were enrolled, and 332 pairs obtained by PSM were applied to the final analyses in the study. An increased incidence of newly d/eOD was observed in the SB group compared with the control group (54.8 vs. 44.6%, p < 0.01). Multivariable logistic regression indicated that the adjusted OR of SBT for this composite outcome was no longer significant [OR (95% CI): 1.39 (0.9, 1.85); p = 0.164]. This effect of SBT did not change with the quintiles stratified by pH. Interestingly, SBT was associated with an increased risk of the composite of newly d/eOD in the subgroup of patients with worsening hemodynamics before SBT [adjusted OR (95% CI): 3.6 (1.84, 7.22), p < 0.001]. Moreover, the risk potential for this composite of outcomes was significantly increased in patients characterized by both worsening [adjusted OR (95% CI): 2.91 (1.54, 5.47), p < 0.001] and unchanged hemodynamics [adjusted OR (95% CI): 1.94 (1.01, 3.72), p = 0.046] compared to patients with improved hemodynamics before SBT. Our study failed to demonstrate an association between SBT and 28-day mortality in acute critically ill patients with metabolic acidosis. Conclusions: Our findings did not demonstrate an association between SBT and outcomes in critically ill patients with metabolic acidosis. However, patients with either worsening or unchanged hemodynamic status in initial resuscitation had a significantly higher risk potential of newly d/eOD subsequent to SBT.

Sodium bicarbonate therapy for metabolic acidosis in critically ill patients: a survey of Australian and New Zealand intensive care clinicians

OBJECTIVE

To help shape the design of a future double blind placebo-controlled randomised clinical trial of bicarbonate therapy for metabolic acidosis, based on opinions of intensive care clinicians in Australia and New Zealand.

DESIGN

An online survey was designed, piloted and distributed electronically to members of the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG) mailing list. The survey sought to collect information about choice of placebo, method of bicarbonate administration, and acid-base monitoring.

MAIN OUTCOME MEASURES

Responses to six questions in the following domains were sought: 1) solution to be used as placebo; 2) method of administration; 3) target of the intervention; 4) timing of arterial blood gases to monitor the intervention; 5) duration of therapy; and 6) rate of bolus therapy (if selected as the best option).

RESULTS

One in every eight ANZICS CTG members completed the survey (118/880, 13.4%). Compound sodium lactate was the preferred solution for placebo (54/118, 45.8%), and continuous infusion of bicarbonate (80/118, 67.8%) was the most frequently selected method of administration. A pH > 7.30 was the preferred target (50/118, 42.4%), while monitoring with arterial blood gas analysis every 2 hours until the target is reached and then every 4 hours was the most favoured option (40/118, 33.9%). The preferred duration of therapy was until the target is achieved (53/118, 44.9%).

CONCLUSIONS

This survey offers important insights into the preferences of Australian and New Zealand clinicians in regards to any future randomised controlled trial of bicarbonate therapy for metabolic acidosis in the critically ill.

Advanced organ support (ADVOS) in the critically ill: first clinical experience in patients with multiple organ failure

Background

Prevalence of multiple organ failure (MOF) in critically ill patients is increasing and associated mortality remains high. Extracorporeal organ support is a cornerstone in the management of MOF. We report data of an advanced hemodialysis system based on albumin dialysis (ADVOS multi device) that can regulate acid–base balance in addition to the established properties of renal replacement therapy and albumin dialysis systems in critically ill patients with MOF.

Methods

34 critically ill patients with MOF received 102 ADVOS treatment sessions in the Department of Intensive Care Medicine of the University Medical Center Hamburg-Eppendorf. Markers of metabolic detoxification and acid–base regulation were collected and blood gas analyses were performed. A subgroup analyses were performed in patients with severe acidemia (pH < 7.2).

Results

Median number of treatment sessions was 2 (range 1–9) per patient. Median duration of treatment was 17.5 (IQR 11–23) hours per session. Treatment with the ADVOS multi-albumin dialysis device caused a significant decrease in bilirubin levels, serum creatinine, BUN and ammonia levels. The relative elimination rate of bilirubin was concentration dependent. Furthermore, a significant improvement in blood pH, HCO₃⁻ and PaCO₂, was achieved during ADVOS treatment including six patients that suffered from severe metabolic acidosis refractory to continuous renal replacement therapy. Delta pH, HCO₃⁻ and PaCO₂ were significantly affected by the ADVOS blood flow rate and pH settings. This improvement in the clinical course during ADVOS treatments allowed a reduction in norepinephrine during ADVOS therapy. Treatments were well tolerated. Mortality rates were 50% and 62% for 28 and 90 days, respectively.

Conclusions

In this case series in patients with MOF, ADVOS was able to eliminate water-soluble and albumin-bound substances. Furthermore, the device corrected severe metabolic and respiratory acid–base disequilibrium. No major adverse events associated with the ADVOS treatments were observed.

Interventions for improving outcomes in acute kidney injury

PURPOSE OF REVIEW

Since the adoption of the classification of acute kidney injury (AKI) through changes in serum creatinine and/or urine output, much data have accumulated as to the associated risks in terms of morbidity and mortality after the development of AKI. However, until recently, a nihilistic approach persisted which implied that little could be done to alter the clinical course of a patient with AKI even where early identification was achieved. This view is reinforced by the opinion that given the broad cause underlying the syndrome of AKI, a 'one size fits all' approach is unlikely to be successful.

RECENT FINDINGS

Recent evidence suggests that the management of AKI may be improved somewhat by simple measures, such as the use of care bundles particularly in the intensive care setting. Moreover, there are other interventions using common treatments, which may prove to be of benefit as well as some early evidence that specific therapeutics may be on the horizon.

SUMMARY

Although a syndrome of significantly differing causes, the application of standardized care bundles appears promising and this approach may be improved by the use of specific therapies, including recombinant alkaline phosphatase, the use of intravenous bicarbonate and remote ischaemic preconditioning may also ameliorate the effects of AKI.