Clinical and Laboratory Characteristics Predicting the Severity of Carbon Monoxide Poisoning in Children: A Single-Center Retrospective Study

OBJECTIVES

Carbon monoxide poisoning (COP) is extremely common throughout the world. The purpose of this study was to assess the demographic, clinical, and laboratory characteristics predicting the severity COP in children.

METHODS

The study included 380 children diagnosed with COP between January 2017 and January 2021 and 380 healthy controls. Carbon monoxide poisoning was diagnosed based on the medical history and a carboxyhemoglobin (COHb) level of more than 5%. The patients were classified as mild (COHb 10%), moderate (COHb 10%-25%), or severely (COHb > 25%) poisoned.

RESULTS

The mean age of the severe group was 8.60 ± 6.30, for the moderate group was 9.50 ± 5.81, for the mild group was 8.79 ± 5.94, and for the control group was 8.95 ± 5.98. The most common place of exposure was at home and all cases were affected accidentally. The coal stove was the most common source of exposure, followed by natural gas. The most common symptoms were nausea/vomiting, vertigo, and headache. Neurologic symptoms such as syncope, confusion, dyspnea, and seizures were more common in the severe group. A total of 91.3% of the children had hyperbaric oxygen therapy, 3.8% were intubated, and 3.8% were transferred to intensive care in the severe group, whereas no death or sequela was observed. Mean platelet volume and red cell distribution width had the highest area under the curve in the receiver operating characteristic analysis (0.659; 0.379). A positive and low statistically significant relationship was found between COHb levels and troponin and lactate levels in the severe group ( P < 0.05).

CONCLUSIONS

Carbon monoxide poisoning progressed more severely in children presented with neurological symptoms and have elevated red cell distribution width and mean platelet volume. Even in severe COP cases, satisfactory results have been obtained with early and appropriate treatment.

Association between Early Phase Serum Lactate Levels and Occurrence of Delayed Neuropsychiatric Sequelae in Adult Patients with Acute Carbon Monoxide Poisoning: A Systematic Review and Meta-Analysis

The primary goal of treating carbon monoxide (CO) poisoning is preventing or minimizing the development of delayed neuropsychiatric sequelae (DNS). Therefore, screening patients with a high probability for the occurrence of DNS at the earliest is essential. However, prognostic tools for predicting DNS are insufficient, and the usefulness of the lactate level as a predictor is unclear. This systematic review and meta-analysis investigated the association between early phase serum lactate levels and the occurrence of DNS in adult patients with acute CO poisoning. Observational studies that included adult patients with CO poisoning and reported initial lactate concentrations were retrieved from the Embase, MEDLINE, Google Scholar and six domestic databases (KoreaMED, KMBASE, KISS, NDSL, KISTi and RISS) in January 2022. Lactate values were collected as continuous variables and analyzed using standardized mean differences (SMD) using a random-effect model. The risk of bias was evaluated using the Quality in Prognosis Studies (QUIPS) tool, and subgroup, sensitivity and meta regression analyses were performed. Eight studies involving a total of 1350 patients were included. The early phase serum lactate concentration was significantly higher in the DNS group than in the non-DNS group in adult patients with acute CO poisoning (8 studies; SMD, 0.31; 95% CI, 0.11−0.50; I2 = 44%; p = 0.002). The heterogeneity decreased to I2 = 8% in sensitivity analysis (omitting Han2021; 7 studies; SMD, 0.38; 95% CI, 0.23−0.53; I2 = 8%; p < 0.001). The risk of bias was assessed as high in five studies. The DNS group was associated with significantly higher lactate concentration than that in the non-DNS group.

Usefulness of a modified poisoning severity score for predicting prognosis in acute carbon monoxide poisoning

INTRODUCTION

The poisoning severity score (PSS) was developed to grade the severity of various types of poisoning. However, in its current form, it requires investigating many variables, some of which have been found not to be associated with carbon monoxide (CO) poisoning severity. Therefore, in this study, we modified the PSS for CO poisoning and compared its usefulness to that of the original PSS, as an early prognostic factor of short-term outcome in CO poisoning patients.

METHODS

This was a retrospective observational study conducted in patients with CO poisoning who visited the emergency department between January 2014 and December 2020. Patients' primary outcome was their Cerebral Performance Category (CPC) scale score at discharge, which classified those with CPC 1-2 as having a favorable outcome and those with CPC 3-5 as having a poor outcome. We calculated the patients' PSS and their CO-modified PSS by replacing blood and metabolic balance category in the original PSS with carboxyhemoglobin (COHb) and lactate levels, respectively.

RESULTS

This study included 891 patients, of which 852 (95.6%) and 39 (4.4%) were classified into the favorable and poor outcome groups, respectively. Using multivariate analysis, the PSS (odds ratio [OR], 22.961; 95% confidence interval [CI], 10.641-49.546; p < 0.001) and CO-modified PSS (OR, 28.856; 95% CI, 12.874-64.679; p < 0.001) were both found to be associated with poor outcomes at hospital discharge. The areas under the receiver operating characteristic curves for the PSS and CO-modified PSS were 0.874 (95% CI, 0.850-0.895) and 0.881 (95% CI, 0.858-0.901), respectively.

CONCLUSION

The CO-modified PSS, with fewer variables than the original PSS, was not inferior to predict poor outcomes, and if COHb level is considered together with other parameters, then it can be used both for predicting prognosis and in diagnosis.

Diagnosis of acute intoxications in critically ill patients: focus on biomarkers - part 2: markers for specific intoxications

In medical intensive care units, acute intoxications contribute to a large proportion of all patients. Epidemiology and a basic overview on this topic were presented in part one. The purpose of this second part regarding toxicological biomarkers in the ICU setting focuses on specific poisons and toxins. Following the introduction of anion and osmol gap in part one, it's relevance in toxic alcohols and other biomarkers for these poisonings are presented within this publication. Furthermore, the role of markers in the blood, urine and cerebrospinal fluid for several intoxications is evaluated. Specific details are presented, amongst others, for cardiovascular drug poisoning, paracetamol (acetaminophen), ethanol, pesticides, ricin and yew tree intoxications. Detailed biomarkers and therapeutic decision tools are shown for carbon monoxide (CO) and cyanide (CN^-) poisoning. Also, biomarkers in environmental toxicological situations such as mushroom poisoning and scorpion stings are presented.

The relationship among plasma copeptin, carboxyhemoglobin, and lactate levels in carbon monoxide poisoning

OBJECTIVE

The aim of our study is to determine whether there is a change in the plasma levels of copeptin and there is a relationship among the plasma levels of carboxyhemoglobin (COHb), lactate, and copeptin levels in patients presenting to the emergency department with carbon monoxide (CO) poisoning.

METHODS

Fifty-seven patients admitted to the emergency department with CO poisoning were included in the study. The blood samples of the patients were collected on arrival 0th, 6th, and 12th hours for copeptin, lactate, and COHb levels. Data were analyzed using SPSS-17 statistical software.

RESULTS

Arrival serum copeptin levels of the patients were compared to copeptin levels of healthy individuals and a statistically significant difference was found between them (p = 0.008). There was a statistically significant difference between the arrival levels of copeptin and 6th-hour (p = 0.006) and 12th-hour (p = 0.001) levels of copeptin. There was no significant difference between 6th-hour and 12th-hour copeptin levels (p = 0.51). In terms of serum lactate levels, there was a significant difference between arrival and 6th h (p < 0.001), arrival and 12th h (p < 0.001), and 6th and 12th h (p < 0.001). Likewise, in terms of serum COHb levels, there was a significant difference between arrival and 6th h (p < 0.001), arrival and 12th h (p < 0.001), and 6th and 12th h (p < 0.001). There was a positive correlation between COHb and lactate levels on arrival (r = 0.52; p = 0.001).

CONCLUSION

Copeptin as a stress hormone can be used in the diagnosis and monitoring of patients with CO poisoning. However, the copeptin level was not superior to COHb and lactate levels.

Demystifying Lactate in the Emergency Department

The role of lactic acid and its conjugate base, lactate, has evolved during the past decade in the care of patients in the emergency department (ED). A recent national sepsis quality measure has led to increased use of serum lactate in the ED, but many causes for hyperlactatemia exist outside of sepsis. We provide a review of the biology of lactate production and metabolism, the many causes of hyperlactatemia, and evidence on its use as a marker in prognosis and resuscitation. Additionally, we review the evolving role of lactate in sepsis care. We provide recommendations to aid lactate interpretation in the ED and highlight areas for future research.

Poison severity score and sequential organ failure assessment score: Carbon monoxide poisoning prognosis

Purpose

We aimed to examine the utility of the Poison Severity Score (PSS) and Sequential Organ Failure Assessment (SOFA) score as early prognostic predictors of short-term outcomes in patients with carbon monoxide (CO) poisoning. We hypothesized that both the PSS and the SOFA score would be useful prognostic tools.

Methods

This was retrospective observational study of patients with CO poisoning who presented to the emergency department and were admitted for more than 24 hours. We calculated PSS, the initial SOFA score, a second (2^nd) SOFA score, and a 24-hour delta SOFA score. The primary outcome was reported as the cerebral performance category (CPC) scale score at discharge. We classified those with CPC 1–2 as the good outcome group and those with CPC 3–5 as the poor outcome group.

Results

This study included 192 patients: 174 (90.6%) belonged to the good outcome group, whereas 18 (9.4%) belonged to the poor outcome group. The PSS (1.00 [0.00, 1.00] vs 3.00 [3.00, 3.00], p < 0.001), initial SOFA (1.00 [0.00, 2.00] vs 4.00 [3.25, 6.00], p < 0.001), 2^nd SOFA score (0.00 [0.00, 1.00] vs 4.00 [3.00, 7.00], p < 0.001), and 24-hour delta SOFA score (-1.00 [-1.00, 0.00] vs 0.00 [-1.00, 1.00], p = 0.047) of the good outcome group were significantly higher than those of the poor outcome group. The areas under the receiver operating characteristic curve for PSS and the initial SOFA and 2^nd SOFA scores were 0.977 (95% confidence interval [CI] 0.944–0.993), 0.945 (95% CI 0.903–0.973), and 0.978 (95% CI 0.947–0.994), respectively.

Conclusion

The PSS, initial SOFA score, and 2^nd SOFA score predict acute poor outcome accurately in patients with CO poisoning.

Determination of netrin-1 levels and its relationship with neurotoxicity in carbon monoxide poisoning

OBJECTIVE

The aim of the study was to assess netrin-1 levels in carbon monoxide (CO) poisoning to determine its relationship with poisoning severity and neurotoxicity.

METHODS

This is a cross-sectional prospective study. The patients older than 18 years with CO poisoning were included. The patients were categorized into two groups on the basis of neurological involvement. Both the patient and the control groups were sampled for netrin-1 at 0th hour, and the patient group only was sampled for netrin-1 at 4th hour.

RESULTS

A total of 84 patients and 50 healthy controls were enrolled. The median 0th hour netrin-1 level of the patient group (765.1 pg/mL (619.8-983.1) was significantly higher than the control group (484 pg/mL (376-1031.6)) ( p < 0.001). There was also a significant difference between the 0th hour and 4th hour netrin-1 (888.9 pg/mL (700.3-1175.5)) levels in the patient group ( p < 0.001).There was no significant statistical difference between patients with and without neurological involvement ( p = 0.62) and between those who underwent hyperbaric oxygen therapy (HBOT) and those who did not ( p = 0.76) with respect to 4th hour netrin-1 levels.

CONCLUSION

The significantly higher netrin-1 levels in patients with CO poisoning, suggests that netrin-1 is elevated as a stress marker. Although there is no significant difference in netrin-1 levels in patients with neurological impairment in CO poisonings, netrin-1 may show subclinically neurological effects. Hence, we believe that netrin-1 cannot be used as a marker of poisoning severity.

Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement

OBJECTIVE

To review the current literature with respect to the physiology, pathophysiology, and measurement of lactate.

DATA SOURCES

Data were sourced from veterinary and human clinical trials, retrospective studies, experimental studies, and review articles. Articles were retrieved without date restrictions and were sourced primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Lactate is an important energy storage molecule, the production of which preserves cellular energy production and mitigates the acidosis from ATP hydrolysis. Although the most common cause of hyperlactatemia is inadequate tissue oxygen delivery, hyperlactatemia can, and does occur in the face of apparently adequate oxygen supply. At a cellular level, the pathogenesis of hyperlactatemia varies widely depending on the underlying cause. Microcirculatory dysfunction, mitochondrial dysfunction, and epinephrine-mediated stimulation of Na⁺ -K⁺ -ATPase pumps are likely important contributors to hyperlactatemia in critically ill patients. Ultimately, hyperlactatemia is a marker of altered cellular bioenergetics.

CONCLUSION

The etiology of hyperlactatemia is complex and multifactorial. Understanding the relevant pathophysiology is helpful when characterizing hyperlactatemia in clinical patients.

Lactate Level Is More Significant Than Carboxihemoglobin Level in Determining Prognosis of Carbon Monoxide Intoxication of Childhood

OBJECTIVES

To evaluate the demographics, risk factors, correlation between carbon monoxide (CO) level and clinical findings, and laboratory findings determining the prognosis and ischemic myocardial injury due to CO intoxication in patients admitted to pediatric emergency department.

MATERIALS AND METHODS

Six hundred seventy-four patients were admitted with CO intoxication between May 2007 and October 2009, 288 patients who required hospitalization were enrolled into the study prospectively.

RESULTS

Incidentally, 144 (50%) of the patients were evenly distributed as girls and boys. Their age ranged between 7 months and 17 years; mean age was 8.6 years. The mean CO level was 26.8. The high levels were detected regarding lactate in 199 (90.1%) patients, creatine kinase (CK)-MB in 130 (45.1%) patients, CK in 80 (27.8%) patients, cardiac Troponin I in 35 (17.2%) patients, and lactate dehydrogenase in 34 (15.7%) patients. There was a significant positive correlation when symptoms like syncope, loss of consciousness, and convulsion were compared with carboxyhemoglobin, lactate, CK, CK-MB, and lactate dehydrogenase levels (P < 0.05), whereas there was no correlation when compared with cardiac Troponin I (P > 0.05). To determine the accuracy of predicting severe CO intoxication, sensitivity of 52.6% and specificity of 85.7% were found in receiver operating characteristic analysis when the lactate level was 3.85 mmol/L, whereas sensitivity of 70.5% and specificity of 59.6% were found when the carboxyhemoglobin level was 27.1%. One hundred forty-six (%50.8) of the patients had normal electrocardiographic findings, whereas 135 (46.8%) had sinus tachycardia, 6 (2%) had right branch block, and 1 (0.34%) had atrioventricular block. In 34 patients who had high CK-MB and Troponin I levels, only sinus tachycardia was detected in electrocardiography, and there were no ST changes. Hyperbaric oxygen was necessary in 2 patients admitted with coma.

CONCLUSIONS

In children admitted because of CO intoxication, the blood lactate levels may give more accurate information in terms of loss of consciousness and convulsion, lactate level could be taken as a measure of severe poisoning and may help to decide for hyperbaric oxygen treatment.