Metabolic Acidosis Assessment in High-Risk Surgeries

Association between albumin-corrected anion gap and in-hospital mortality of intensive care patients with trauma: A retrospective study based on MIMIC-Ⅲ and Ⅳ databases

BACKGROUND

To investigate the correlation between albumin-corrected anion gap(ACAG) within the first 24 hours of admission and in-hospital mortality in trauma patients in intensive care unit(ICU).

MATERIALS AND METHODS

We utilized the MIMIC-Ⅲ and MIMIC-Ⅳ databases to examine trauma patients admitted to the ICU. The relationship between ACAG and in-hospital mortality in trauma patients was analyzed using Receiver Operating Characteristic(ROC) curve, Kaplan-Meier (K-M) survival curve, and Cox regression model. Propensity score matching (PSM) and subgroup analysis were conducted to enhance stability and reliability of the findings. Mortality at 30-day and 90-day served as secondary outcomes.

RESULTS

The study enrolled a total of 1038 patients. The AUC for ACAG (0.701, 95%CI: 0.652-0.749) was notably higher than that for anion gap and albumin. The Log-rank test revealed that the optimal cut-off point of ACAG for predicting in-hospital mortality was determined to be 20.375mmol/L. The multivariate Cox regression analysis demonstrated an independent association between high ACAG level and a higher risk of in-hospital mortality (HR = 3.128, 95% CI: 1.615-6.059). After PSM analysis, a matched cohort consisting of 291 subjects was obtained. We found no signifcant interaction in most stratas. Finally, The in-hospital, 30-day, and 90-day survival rates in the high ACAG group exhibited a statistically decrease compared to those in the low ACAG group both pre- and post-matching.

CONCLUSION

The elevated level of ACAG was found to be independently associated with increased in-hospital mortality among trauma patients in the ICU.

The hidden secrets of a neutral pH-blood gas analysis of postoperative patients according to the Stewart approach

Background

The superiority of either the traditional or Stewart based approach to acid-base balance has focused primarily on analyzing metabolic acidemia, with little attention given to patients with neutral pH. In this study, we evaluate metabolic disturbances in patients in the immediate postoperative period focusing on patients with neutral pH, while comparing the Stewart and traditional approach.

Methods

We conducted a single center retrospective observational cohort study. Over a 17-month period, data on arterial blood gas analysis, electrolytes, and albumin on the morning after surgery were retrieved from patients admitted to the postsurgical high dependency unit (HDU). Albumin-corrected anion gap (AG), apparent (SIDa) and effective strong ion difference (SIDe), and strong ion gap (SIG) were calculated.

Results

Out of 1207 HDU admissions, 400 cases had a complete set of laboratory-data including albumin of which 281 presented with neutral pH (7.35 ≤ pH ≤ 7.45), 64 with acidemia (pH < 7.35) and 55 with alkalemia (pH > 7.45). In pH neutral patients, the following acidifying disturbances were found: SIDa was lowered in 101 (36%), and SIG was raised in 60 (21%). Base excess (BE) was decreased in 16 (6%) and corrected AG raised in 107 (38%). The alkalizing effect of hypoalbuminemia was present in 137 (49%). Out of 134 cases with normal BE and corrected AG, SIDa was lowered in 58 (43%). Out of 136 cases with normal SIDa and SIG, none had lowered BE and 28 increased AG (21%). Length of stay was significantly longer in patients with hypoalbuminemia, lowered SIDa, and increased corrected AG, but not decreased BE (hypoalbuminemia: 16 days vs. 10 days, P < 0.001; low SIDa: 15 days vs. 12 days, P = 0.015; increased AG: 16 days vs. 11 days, P < 0.001; low BE: 14 days vs. 13 days, P = 0.736).

Conclusions

Metabolic disturbances, characterized mainly by the presence of lowered SIDa, increased AG, and hypoalbuminemia, are frequent in our population with apparent neutral acid-base balance based on pH and base excess. These changes on the morning after surgery are associated with increased length of stay.

Effects of intraoperative adrenergic administration on postoperative hyperlactatemia in open colon surgery: an observational study

Background

Postoperative Hyperlactatemia (PO-HL) is a frequent condition associated with poor prognosis. In recent years, there has been growing evidence that adrenergic stimulation may contribute to increased lactate levels. The use of adrenergic agonists for the control of intraoperative hypotension is frequent, and its impact on the development of PO-HL is unknown.

Objective

To evaluate whether the use of intraoperative adrenergic agents is associated with the occurrence of PO-HL.

Methods

This was a prospective observational study. The inclusion criteria were undergoing elective open colon surgery, being ≥60 years old and signing informed consent. The exclusion criteria were cognitive impairment, unplanned surgery, and anticipated need for postoperative mechanical ventilation. Baseline and intraoperative variables were collected, and arterial lactate data were collected at baseline and every 6 hours postoperatively for 24 hours. Hyperlactatemia was defined as lactate >2.1 mEq.L^-1.

Results

We studied 28 patients, 61% of whom developed hyperlactatemia. The variables associated with PO-HL in the univariate analysis were anesthetic time, the total dose of intraoperative ephedrine, and lower intraoperative central venous oxygen saturation (ScvO₂). Multivariate analysis confirmed the association between the use of ephedrine (p = 0.004), intraoperative hypotension (p = 0.026), and use of phenylephrine (p = 0.001) with PO-HL.

Conclusions

The use of intraoperative ephedrine, phenylephrine and intraoperative hypotension were independently associated with the development of PO-HL. This finding should lead to new studies in this field, as well as a judicious interpretation of the finding of a postoperative increase in lactate levels.

Hyperlactatemia during cardiopulmonary bypass: risk factors and impact on surgical results with a focus on the long-term outcome

INTRODUCTION

Lactate, a product of anaerobic metabolism, is a biomarker and indicator for tissue hypoperfusion and oxygen debt. An elevated blood lactate level has been associated with poor outcome in many clinical conditions, including cardiac surgery. Nevertheless, debate exists regarding which blood lactate concentration is most indicative of poor outcomes. We evaluate the impact of hyperlactatemia, defined as a peak arterial blood concentration ⩾2.0 mmol/L during cardiopulmonary bypass, on surgical results with a focus on long-term outcome.

METHODS

We reviewed 1,099 consecutive adult patients who underwent cardiac surgery on pump. The patients were divided into two groups based on the presence or not of hyperlactatemia. Pre- and intraoperative risk factors for hyperlactatemia were identified, and the postoperative outcome of patients with or without hyperlactatemia was compared.

RESULTS

Hyperlactatemia was present in 372 patients (33.8%). Factors independently associated with hyperlactatemia were urgent/emergency procedure, cardiopulmonary bypass duration and aortic cross-clamp time. Patients with hyperlactatemia had significantly higher rate of prolonged mechanical ventilation time, in-hospital stay and requirement of inotropes and intra-aortic balloon pump support (p < 0.001). Operative (30-day) mortality was higher in the group of patients with hyperlactatemia (7.8% vs. 1.1%; p < 0.001). Kaplan-Meier curve showed worse long-term survival (mean follow-up: 4.02 ± 1.58 years) in patients with hyperlactatemia.

CONCLUSION

Hyperlactatemia during cardiopulmonary bypass has a significant association with postoperative morbidity and mortality. Correction of risk factors for hyperlactatemia, together with prompt detection and correction of this condition, may control complications and improve outcome.

The arterial blood gas algorithm: Proposal of a systematic approach to analysis of acid-base disorders

Abnormalities in the acid-base balance are common clinical problems and can have deleterious effects on cellular function and be a clue to various disorders. Therefore, it is important for the clinician to make a precise diagnosis of the acid-base disorder(s) present for a proper treatment. Three approaches have been proposed to evaluate acid-base disorders: a bicarbonate-centric approach; the Stewart approach, and the base excess approach. Although the latter two have many adherents, we will only discuss the bicarbonate-centric approach. This approach is simpler to utilize at the bedside, has a physiological evaluation of the acid-base disorder, presents an easily understandable approach to assess severity, and provides a more solid foundation for the development of effective therapies. Therefore, the following discussion will be limited to an examination of this approach. In this case-centric review, important new concepts will be introduced first; their benefits and limitations discussed; and then their utilization to analyze actual cases will be shown. A systematic approach algorithm that incorporates these new concepts has been generated and will be highlighted.

Relationship of at Admission Lactate, Unmeasured Anions, and Chloride to the Outcome of Critically Ill Patients

OBJECTIVES

To investigate the association between the concentration of the causative anions responsible for the main types of metabolic acidosis and the outcome.

DESIGN

Prospective observational study.

SETTING

Teaching ICU.

PATIENTS

All patients admitted from January 2006 to December 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Four thousand nine hundred one patients were admitted throughout the study period; 1,609 met criteria for metabolic acidosis and 145 had normal acid-base values. The association between at admission lactate, unmeasured anions, and chloride concentration with outcome was assessed by multivariate analysis in the whole cohort and in patients with metabolic acidosis. We also compared the mortality of patients with lactic, unmeasured anions, and hyperchloremic metabolic acidosis with that of patients without acid-base disorders. In the whole population, increased lactate and unmeasured anions were independently associated with increased mortality, even after adjusting for potential confounders (odds ratio [95% CI], 1.14 (1.08-1.20); p < 0.0001 and 1.04 (1.02-1.06); p < 0.0001, respectively). In patients with metabolic acidosis, the results were similar. Patients with lactic and unmeasured anions acidosis, but not those with hyperchloremic acidosis, had an increased mortality compared to patients without alterations (17.7%, 12.7%, 4.9%, and 5.8%, respectively; p < 0.05).

CONCLUSIONS

In this large cohort of critically ill patients, increased concentrations of lactate and unmeasured anions, but not chloride, were associated with increased mortality. In addition, increased unmeasured anions were the leading cause of metabolic acidosis.

Recommendations for perioperative management of lung cancer patients with comorbidities

Objectives

To improve surgical outcomes, clinicians must provide optimal perioperative care for comorbidities identified as significant factors in risk models for patients undergoing lung cancer surgery.

Methods

We reviewed trends in perioperative care for idiopathic pulmonary fibrosis, cardiovascular diseases, and end-stage renal diseases in patients undergoing lung cancer surgery, as large clinical databases indicate that these comorbidities are significant risk factors for lung cancer surgery. Articles identified by keyword searches were included in the analysis.

Results

Significant predictive factors for acute exacerbation of idiopathic pulmonary fibrosis were identified. However, no effective perioperative care was identified for prevention of acute exacerbation of interstitial pneumonia. The timing of coronary revascularization and antithrombotic management for cardiovascular diseases are subjects of ongoing research, and acid–base balance is essential in the management of hemodialysis patients with end-stage renal diseases.

Conclusions

To improve surgical outcomes for lung cancer patients, future studies should continue to study optimal perioperative management of comorbidities.

Subcellular Energetics and Metabolism: Potential Therapeutic Applications

Part I of this review discussed the similarities between embryogenesis, mammalian adaptions to hypoxia (primarily driven by hypoxia-inducible factor-1 [HIF-1]), ischemia-reperfusion injury (and its relationship with reactive oxygen species), hibernation, diving animals, cancer, and sepsis, and it focused on the common characteristics that allow cells and organisms to survive in these states. Part II of this review describes techniques by which researchers gain insight into subcellular energetics and identify potential future tools for clinicians. In particular, P nuclear magnetic resonance to measure high-energy phosphates, serum lactate measurements, the use of near-infrared spectroscopy to measure the oxidation state of cytochrome aa3, and the ability of the protoporphyrin IX-triplet state lifetime technique to measure mitochondrial oxygen tension are discussed. In addition, this review discusses novel treatment strategies such as hyperbaric oxygen, preconditioning, exercise training, therapeutic gases, as well as inhibitors of HIF-1, HIF prolyl hydroxylase, and peroxisome proliferator-activated receptors.