The time between paraquat ingestion and a negative dithionite urine test in an independent risk factor for death and organ failure in acute paraquat intoxication

Acute paraquat poisoning in an adolescent with compromised outcome: A case report

Paraquat, a highly toxic herbicide, accounts for a substantial number of poisoning-related fatalities, primarily prevalent in agricultural regions. The ingestion gives rise to severe complications affecting various organs, including the lungs, gastrointestinal tract, kidneys and liver. This report details the case of an 18-year-old male who had been using cannabis for a year and inadvertently ingested paraquat. He presented at the emergency room exhibiting symptoms of vomiting characterized by hematemesis and regurgitated food particles, along with heartburn, dysphagia and reduced urine output. Given the absence of a specific antidote, the prognosis for paraquat poisoning remains generally unfavourable. Diagnosis relies on circumstantial evidence and clinical manifestations, necessitating a focus on supportive care. Presently, no specific antidote for paraquat poisoning is available. Efforts should concentrate on preventive measures, efficient decontamination strategies and vigilant stabilization protocols in instances of exposure.

Prediction of mortality and morbidity following paraquat poisoning based on trend of liver and kidney injury

Background

Paraquat is a non-selective herbicide that causes severe tissue damage in various organs including the liver and kidney. The aim of this study was to determine the trend of the liver and kidney injury in patients with paraquat poisoning.

Methods

This retrospective cross-sectional study was performed at the Khorshid Hospital referral poisoning emergency center. The medical records of all patients with acute paraquat poisoning admitted from March 2017 to October 2020 were reviewed. Demographic factors, liver and kidney function tests and outcomes were recorded. Patients were divided into two groups based on the outcome of mortality (death or survived). The two groups were compared in terms of changes in creatinine and liver enzymes during hospitalization.

Results

A significant difference in mean creatinine levels between the two groups was observed from the third day after admission. The peak median Cr was 3.5 mg/dl for deceased patients in day 6 and 1.47 mg/dl for survived patients on 4th day. Minor elevations of ALT and AST were present in those who died. Logistic regression analysis shows patients who had level of creatinine higher than normal from the 2nd to 6th day post overdose, the risk of mortality was 4.83 to 7.44 times more than patients with normal creatinine level. The mean (SD) area under the curve for outcome prediction was reported to be excellent for creatinine on the 8th day post overdose (85.7 ± 13.2). Creatinine was higher than 2 on the 8th day post ingestion and had a sensitivity 100% and specificity 85.7% for mortality prediction (P value, 0.05).

Conclusions

The risk of mortality secondary to paraquat ingestion was highly associated with a rise in creatinine. Minor elevations of ALT and AST were also present in those who died. The creatinine concentration on different days post overdose can be helpful in predicting the severity of poisoning especially when the serum paraquat levels are not available.

Comparison of Biochemical Parameters between Mouse Model and Human after Paraquat Poisoning

Background. This study was designed to investigate differences in biochemical parameters between mouse and humans after paraquat (PQ) poisoning and develop a suitable animal model for studying organ damage after PQ poisoning. The prognostic factors of PQ-poisoned patients were further analyzed. Methods. Thirty C57BL/6J mice were randomly divided into five groups (control, sham, and 3 PQ doses), and the mouse model was established by intragastric administration of PQ. Physiological indexes such as the body weight, mental state, and mortality rate were observed. Biochemical parameters were analyzed 24 h after PQ poisoning. We also performed a retrospective analysis of clinical data from 29 patients with PQ poisoning admitted to the Emergency Department of the Affiliated Hospital of Taishan Medical College between April 2016 and February 2018. Biochemical parameters were compared between the mouse model and patients with PQ poisoning. Results. In the PQ poisoning mouse model, the lethal dose group PQ360 showed remarkable increases in serum levels of potassium (K+), carbon dioxide (CO2), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) compared with the nonlethal dose PQ100 and PQ200 groups. The biochemical results of the patients showed that K+ and Cl- levels were significantly reduced in the death group compared to the survival group. Levels of ALT, AST, blood urea nitrogen (BUN), and amylase were higher, and the neutrophil-to-lymphocyte ratio (NLR) was increased in the death group compared with the survival group. Conclusions. The combination of age, PQ dosage, K+, Cl-, BUN, ALT, AST, amylase, and NLR can be used to more accurately predict the outcome of patients with PQ poisoning. C57 mice are an appropriate animal model to study liver and kidney functions following PQ exposure.

Prognostic value of liver and kidney function parameters and their correlation with the ratio of urine-to-plasma paraquat in patients with paraquat poisoning

Acute paraquat poisoning resulting from multiple organ failure usually has a high mortality rate. Liver and kidney, as the key oranges of paraquat detoxification and elimination, their injuries may suppress toxin excretion and enhance the toxicity of paraquat in other organs and worsen the prognosis. Therefore, we intended to explore the prognostic value of liver and kidney function parameters, and further evaluate their correlation with a more stable index urine-to-plasma paraquat (urine paraquat concentrations/plasma paraquat concentrations) instead of considering paraquat concentrations in plasma or urine alone. The study included 33 patients with acute paraquat poisoning admitted to four centres in China from January 2018 to December 2019. Seventeen patients (10 male/7 female) survived, whereas 16 patients (7 male/9 female, 48.48%) died from paraquat poisoning. Alanine aminotransferase (ALT) and the blood urea nitrogen (BUN) represent liver and kidney function parameters, respectively. The ratio of urine-to-plasma paraquat is negatively correlated with ALT (r = -0.94, P = 0 .02) and BUN (r = -0.82, P = 0.03). For receiver operating characteristic curve (ROC) analysis, ALT, BUN and urine-to-plasma paraquat have an AUC over 0.80. The study shows that the functional indexes of liver and kidney, as well as the ratio of urine-to-plasma paraquat, could be considered for evaluating the extent of organ injury and excretion rate of paraquat.

Simultaneous determination of paraquat and diquat in human plasma by HPLC-DAD: Its application in acute poisoning patients induced by these two herbicides

Background

Paraquat and diquat are widely used in agricultural production in many countries, which are very toxic to human beings. Paraquat can be detected in some diquat solution sold in the market. The blood concentration of paraquat or diquat is an important indicator for clinical diagnosis of paraquat or diquat poisoning. So, it is very meaningful to develop a method for simultaneous determination of paraquat and diquat in human plasma.

Objective

To develop and validate a HPLC‐DAD method for simultaneous determination of paraquat and diquat in human plasma and to apply it in the acute poisoning patients by these two herbicides.

Methods

Paraquat and diquat were simultaneously determined by HPLC‐DAD. The plasma was treated using Waters OASIS^® Column and then separated on a Thermo Hypersil GOLD (250 × 4.6 mm, 5 μm) Column with the mobile phase consisted of 75 mmol/L sodium heptane sulfonate (containing 0.1 mol/L phosphoric acid, pH 3.0) and acetonitrile (87:13, v:v) at a flow rate of 1.0 mL/min. The full‐wavelength scanning was 200‐400 nm, and the detection wavelength of paraquat and diquat was 257nm and 310nm, respectively. 120 and 30 plasma samples from patients with paraquat and diquat poisoning were collected and analyzed by the established method.

Results

The standard curve for paraquat and diquat ranged from 0.05 to 20 μg/mL, and the precision of LLOQ for paraquat was 16.49%, which was required to be less than 20%. The precision of other concentrations was less than 14.14%. The recovery of paraquat and diquat was 95.38%‐103.97% and 94.79%‐98.40%, respectively. The results showed that paraquat and diquat were stable under various storage conditions. 120 plasma samples of paraquat poisoning patients and 30 plasma samples of diquat poisoning patients were determined by the established method. The blood concentration of paraquat ranged from 0.10 to 20.62 μg/mL, with an average of 3.61 μg/mL, while for diquat, the concentration ranged from 0 to 26.59 μg/mL, with an average of 2.00 μg/mL. Among the diquat suspected poisoning samples, 5 samples were detected not only diquat but also paraquat, and 2 samples were detected only paraquat, no diquat.

Conclusion

The HPLC‐DAD method established in this study was high throughput, high sensitivity, simple operation, and wide linear ranges. It can be used for the screening analysis and quantitative detection of paraquat and diquat in acute poisoning patients, which can provide basis for the treatment and prognosis of these two herbicides poisoning patients.

Comparison of severity index and plasma paraquat concentration for predicting survival after paraquat poisoning: A meta-analysis

BACKGROUND

Severity index and plasma paraquat (PQ) concentration can predict the prognosis of patients with PQ poisoning. However, the better parameter is yet to be systematically investigated and determined. Thus, we conduct this systematic review and meta-analysis to investigate the prognostic value of severity index and plasma PQ concentration in patients with PQ poisoning.

METHODS

We searched PubMed, Embase, Web of Science, ScienceDirect, and Cochrane Library to identify all relevant papers that were published up to March 2019. All diagnostic studies that compared severity index and plasma PQ concentration to predict mortality in patients with PQ poisoning were enrolled in this meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) for individual trials were pooled using a random-effect model. We also aggregated heterogeneity testing, sensitivity analysis, and publication bias analysis.

RESULTS

Ultimately, seven studies involving 821 patients were included. The pooled OR with a 95% CI of severity index was 24.12 (95% CI: 9.34-62.34, P < .001), with an area under the curve of 0.88 (95% CI: 0.85-0.90), sensitivity of 0.84 (95% CI: 0.74-0.91), and specificity of 0.81 (95% CI: 0.75-0.87). Meanwhile, the pooled OR with 95% CI of plasma PQ concentration was 34.39 (95% CI: 14.69-80.56, P < .001), with an area under the curve of 0.94 (95% CI: 0.91-0.96), sensitivity of 0.86 (95% CI: 0.75-0.93), and specificity of 0.89 (95% CI: 0.76-0.95). Sensitivity analysis demonstrated the stability of the results of our meta-analysis. No significant publication bias was observed in this meta-analysis.

CONCLUSION

Overall, this study indicated that severity index and plasma PQ concentration have relatively high-prognostic value in patients with PQ poisoning, and that the sensitivity and specificity of plasma PQ concentration are superior to those of severity index.

Evaluation of gastric lavage efficiency and utility using a rapid quantitative method in a swine paraquat poisoning model

BACKGROUND

Gastric lavage (GL) is one of the most critical early therapies for acute paraquat (PQ) poisoning; however, details of the treatment protocol remain to be established.

METHODS

A rapid quantitative method involving sodium dithionite testing was developed. It was validated for the determination of the PQ concentrations in gastric juice and eluate samples from a swine acute PQ poisoning model with early or delay GL, or without. The vital signs, laboratory testing, and PQ plasma concentrations were collected for therapeutic effect evaluation.

RESULTS

The reaction conditions of the test were optimized for two types of samples. Early GL at one hour (H1) could improve the signs and symptoms after acute PQ poisoning at 24 hours (H24). In contrast, GL at 6 hours (H6) could only partially relieve the vital signs. The H1 GL group effectively reduced the peak of the plasma PQ concentration. In addition, the PQ concentrations in the plasma and the gastric juice were significantly decreased in both the GL groups as compared to the untreated group at H24. Moreover, there was no significant difference in the washing efficiencies calculated from the total eluates between the two GL groups. However, the washing efficiency of the first 10 L eluate is superior to that of the additional 10 L eluate.

CONCLUSION

GL only at early stage may it benefit PQ poisoning in an animal model. The currently used 20 L GL volume may need to be reduced in view of the low washing efficiency in the later 10 L eluate. The rapid quantitative method can be used for gastric juice sample and has a certain value for clinical GL practices.

Clinical Features, Treatment, Prognosis, and Mortality in Paraquat Poisonings: A Hospital-Based Study in Iran

Objective:

The aim of the present study was to evaluate the demographics, clinical characteristics, fatal dose, the efficacy of treatments, and prognosis in paraquat (PQ) poisoning in the Kerman Province of Iran.

Methods:

This analytical cross-sectional study was conducted on 126 PQ poisoned patients who were referred to Afzalipour Hospital during 2006–2015. Demographic variables such as age and gender, signs and symptoms of poisoning, the estimated ingested dosage of PQ, and clinical outcome were extracted from medical records. Patients were compared and categorized into two groups considering the outcome: survivors and nonsurvivors. Patients with nonoral exposures, combined drug exposures, PQ exposures more than 24 h before the presentation, and critical underlying diseases were not included in the study.

Findings:

Our results indicated that the mean dose of PQ used by all patients was 2358 mg, which was reported as 1846 and 2812 mg in females and males, respectively. Moreover, the results showed that the highest mortality rate was in patients with respiratory distress, followed by oral ulceration and excess salivation. In all PQ-poisoned patients, the dose of greater than approximately 2250 mg predicted death with 86.2% specificity and 75.7% sensitivity.

Conclusion:

Based on the results of the present study, the mortality rate in PQ-poisoned patients depended on the dose of poison, blood sugar level, and aspartate transaminase levels. Our results suggest that these parameters have excellent prognostic value for the prediction of mortality.

Neutrophil-lymphocyte ratio as an early predictor for patients with acute paraquat poisoning: A retrospective analysis

This retrospective study aimed to investigate whether the neutrophil-lymphocyte ratio (NLR) can be used as an early predictor of 90-day survival in patients with acute paraquat (PQ) poisoning.This study enrolled 105 patients with acute PQ poisoning admitted from May 2012 to May 2018. Kaplan-Meier curve, receiver operating characteristic curve, and Cox proportional hazards regression analyses were used to investigate the predictive value of NLR for 90-day survival of patients with acute PQ poisoning.The 90-day survival rate was 40.95% (43/105). Survivors had lower NLR (P <.001), which was an independent predictor of 90-day survival according to the Cox proportional hazard regression analyses. The area under the NLR curve was 0.842 (95% CI: 0.767-0.917, P <.001) in predicting 90-day survival.Our findings showed that low NLR was a valuable early predictor of 90-day survival in patients with acute PQ poisoning.

Clinical features and risk factors of acute kidney injury in children with acute paraquat intoxication

Objective

This study aimed to investigate the clinical features and risk factors of acute kidney injury (AKI) in children with acute paraquat intoxication.

Methods

A retrospective study of 110 hospitalized children with acute paraquat intoxication in West China Second University Hospital, Sichuan University was conducted from January 2010 to May 2017. The Kaplan–Meier method was used to compare the survival rates of children with different AKI stages. Multivariate logistic regression was applied to analyse the risk factors for paraquat-induced AKI.

Results

AKI occurred in 42 of 110 (38.2%) children. We observed AKI stage 1 in two (4.8%) children, AKI stage 2 in 11 (26.2%), and AKI stage 3 in 29 (69.0%). The survival rate of children in AKI stage 3 (34.5%) was significantly lower than that in children in AKI stage 2 (63.6%) and AKI stage 1 (100%). Multivariate analysis showed that oral ulcers and elevated blood glucose levels were significant independent risk factors for paraquat-induced AKI in children (odds ratio = 4.223 and 5.545, respectively).

Conclusions

The incidence and mortality rates of paraquat-induced AKI in children are high. Oral ulcers and elevated blood glucose levels are independent risk factors affecting the occurrence of paraquat-induced AKI in children.

Prognostic significance of urine paraquat concentrations of patients with acute paraquat poisoning on admission at the emergency department

Objective:

To assess the prognostic significance of urine paraquat concentrations of patients with acute paraquat poisoning on admission at the emergency department.

Methods:

Patients with acute paraquat poisoning admitted to the emergency department were recruited. Survivors and non-survivors were compared with regard to urinary paraquat concentration. The urinary level predictive of mortality was assessed by receiver operating characteristic curve. Risk factors of mortality were evaluated by regression analysis.

Results:

The overall mortality rate was 70.9% over the 28-day follow-up period. There was a significant difference in the urine paraquat concentrations recorded on admission between non-surviving and surviving patients ( p = 0.022). Receiver operating characteristic curve analysis revealed that the area under the curve when applied to receiver operating characteristic of the admission urine paraquat concentrations for predicting mortality was 0.854 with a cut-off value of 34.5 µg/mL. The dose of paraquat ingested, arterial lactate, and urine concentration were independent risk factors predicting 28-day mortality. The time interval between ingestion and hemoperfusion, arterial lactate, and urine concentration of paraquat were independent risk factors predicting acute kidney injury, while the partial pressure of carbon dioxide (PaCO2) and urine concentration of paraquat were independent risk factors predicting acute lung injury.

Conclusion:

The urine concentrations of paraquat on admission at emergency department demonstrated predictive ability for the prognosis of patients with acute paraquat poisoning.

Point-of-care testing in the early diagnosis of acute pesticide intoxication: The example of paraquat

Acute pesticide intoxication is a common method of suicide globally. This article reviews current diagnostic methods and makes suggestions for future development. In the case of paraquat intoxication, it is characterized by multi-organ failure, causing substantial mortality and morbidity. Early diagnosis may save the life of a paraquat intoxication patient. Conventional paraquat intoxication diagnostic methods, such as symptom review and urine sodium dithionite assay, are time-consuming and impractical in resource-scarce areas where most intoxication cases occur. Several experimental and clinical studies have shown the potential of portable Surface Enhanced Raman Scattering (SERS), paper-based devices, and machine learning for paraquat intoxication diagnosis. Portable SERS and new SERS substrates maintain the sensitivity of SERS while being less costly and more convenient than conventional SERS. Paper-based devices provide the advantages of price and portability. Machine learning algorithms can be implemented as a mobile phone application and facilitate diagnosis in resource-limited areas. Although these methods have not yet met all features of an ideal diagnostic method, the combination and development of these methods offer much promise.

Prognostic comparison of goal-oriented hemoperfusion and routine hemoperfusion combined with continuous venovenous hemofiltration for paraquat poisoning

Objective

To investigate the impact of goal-oriented hemoperfusion (HP) with monitoring of the paraquat concentration on the prognosis of patients with acute paraquat poisoning.

Methods

This prospective observational study involved patients with acute paraquat poisoning admitted from March 2012 to September 2015. The patients received either goal-oriented or routine HP. All other treatments were the same between the two groups. The primary endpoint was 28-day mortality after poisoning. The secondary endpoints were the incidence of organ dysfunction within 7 days and 7-day mortality.

Results

Eighty-four patients were enrolled (49 in the control group and 35 in the goal-oriented group). The two groups were similar in terms of clinical characteristics. There was no significant difference in the incidence of organ dysfunction between the two groups within 1 week of admission. Mortality on day 7 was significantly lower in the goal-oriented than control group, but there was no difference on day 28. However, 28-day mortality was significantly lower in the goal-oriented group among patients with an oral dose of ≤50 ml.

Conclusions

HP with monitoring of the urine paraquat concentration as goal-oriented therapy can reduce the early mortality of paraquat poisoning.

Hypokalemia is a biochemical signal of poor prognosis for acute paraquat poisoning within 4 hours

Anecdotal reports have suggested that hypokalemia is an independent predictor of mortality in patients with acute paraquat poisoning. However, the clinical significance of hypokalemia has not been systematically investigated in the early stage of paraquat poisoning. This study aimed to evaluate whether initial hypokalemia is a good predictor of mortality in patients with acute paraquat poisoning within 4 h. We retrospectively analyzed patients who were admitted to the emergency department after paraquat poisoning between September 2012 and January 2015. Demographic, clinical, and laboratory data were recorded, and the prognostic significance of hypokalemia was analyzed. A total of 120 patients were included. The 60-day mortality was 71.7 %. Serum potassium concentrations were significantly lower in non-survivors (3.1 ± 0.5 mmol/L) than in survivors (3.8 ± 0.3 mmol/L, P < 0.001). Independent predictors of death were amount of paraquat ingested (hazard ratio 1.005; 95 % confidence interval 1.002-1.007), serum potassium (0.498, 0.277-0.897), bicarbonate (0.934, 0.876-0.995), and white blood cell count (1.032, 1.001-1.065). For receiver operating characteristic curve analysis, serum potassium had an area under the curve of 0.852 (95 % confidence interval 0.784-0.920, P < 0.001), and the best cutoff value was 3.5 mmol/L (sensitivity, 88.2 %; specificity, 75.6 % in predicting survivors). Kaplan-Meier analysis showed that decreased serum potassium concentrations were associated with an increase in 60-day mortality (P < 0.001). Hypokalemia may be a reliable predictor in evaluating prognosis in paraquat poisoning within 4 h. The mechanism is not clear, and further studies verifying the precise mechanism of hypokalemia are required.

Effects of hemoperfusion and continuous renal replacement therapy on patient survival following paraquat poisoning

Mortality in patients with paraquat (PQ) poisoning is related to plasma PQ levels. Concentrations lower than 5,000 ng/mL are considered critical but curable. This study assessed the effects of hemoperfusion (HP) and continuous renal replacement therapy (CRRT) on the survival of PQ-poisoned patients with plasma PQ levels below 5,000ng/mL. We analyzed the records of 164 patients with PQ poisoning who were treated at the First Affiliated Hospital of Wenzhou Medical University in China between January 2011 and May 2015. We divided these patients into six sub-groups based on baseline plasma PQ levels and treatment, compared their clinical characteristics, and analyzed their survival rates. Patient sub-groups did not differ in terms of age, sex, time between poisoning and hospital admission, or time to first gavage. Biochemical indicators improved over time in all sub-groups following treatment, and the combined HP and CRRT treatment yielded better results than HP or CRRT alone. Fatality rates in the three treatment sub-groups did not differ among patients with baseline plasma PQ levels of 50–1,000 ng/mL, but in patients with 1,000–5,000 ng/mL levels, the mortality rate was 59.2% (HP treatment group), 48% (CRRT treatment group), and 37.9% (combined treatment group). Mortality rates were higher 10–30 days after hospitalization than in the first 10 days after admission. In the early stages of PQ poisoning, CRRT is effective in reducing patient fatality rates, particularly when combined with HP. Our data could be useful in increasing survival in acute PQ poisoning patients.

Time-dependent haemoperfusion after acute paraquat poisoning

Early haemoperfusion (HP) therapy has been found to be very effective in acute paraquat (PQ) poisoning, but the effective rescue window is still uncertain. Demographic data and the type of therapies administered of 621 patients were included as confounding factors in this retrospective study. After receiver operating characteristic curve analysis and intra-group/subgroup analysis, the initiation of glucocorticoid therapy within 3 hrs of exposure with a second treatment given <21 hrs after exposure, HP initiated within 4 hrs of exposure with a second treatment given <20 hrs after exposure, the appearance of pulmonary lesions ≤8 days after exposure and six other variables were used in a multiple analysis. The strength of positivity of the PQ urine test on admission, HP initiated within 4 hrs of exposure with a second treatment given <20 hrs after exposure, the appearance of pulmonary lesions ≤8 days after exposure, and stage III AKI on admission were independent factors of survival probability. HP therapy for acute PQ poisoning was the main therapeutic intervention investigated in this study. Outcomes were time dependent, and the crucial factor was the initiation of therapy within 4 hrs of PQ poisoning followed by a second treatment within 20 hrs.

Predictors of acute kidney injury after paraquat intoxication

Paraquat intoxication is characterized by multi-organ failure, causing substantial mortality and morbidity. Many paraquat patients experience acute kidney injury (AKI), sometimes requiring hemodialysis. We observed 222 paraquat-intoxicated patients between 2000 and 2012, and divided them into AKI (n = 103) and non-AKI (n = 119) groups. The mortality rate was higher for AKI than non-AKI patients (70.1% vs. 40.0%, P < 0.001). Patients with AKI had a longer time to hospital arrival (P = 0.003), lower PaO₂ (P = 0.006) and higher alveolar-arterial O₂ difference (P < 0.001) 48 h after admission, higher sequential organ failure assessment 48-h score (P < 0.001), higher severity index of paraquat poisoning (SIPP) score (P = 0.016), lower PaCO₂ at admission (P = 0.031), higher PaO₂ at admission (P = 0.015), lower nadir PaCO₂ (P = 0.001) and lower nadir HCO₃ (P = 0.004) than non-AKI patients. Multivariate logistic regression indicated that acute hepatitis (P < 0.001), a longer time to hospital arrival (P < 0.001), higher SIPP score (P = 0.026) and higher PaO₂ at admission (P = 0.014) were predictors of AKI. The area under the receiver operating characteristic curve confirmed that an Acute Kidney Injury Network 48-hour score ≥ 2 predicted AKI necessitating hemodialysis with a sensitivity of 0.6 and specificity of 0.832. AKI is common (46.4%) following paraquat ingestion, and acute hepatitis, the time to hospital arrival, SIPP score and PaO₂ at admission were powerful predictors of AKI. Larger studies with longer follow-up durations are warranted.

Predictive values of urine paraquat concentration, dose of poison, arterial blood lactate and APACHE II score in the prognosis of patients with acute paraquat poisoning

The present study investigated the predictive values of urine paraquat (PQ) concentration, dose of poison, arterial blood lactate and Acute Physiology and Chronic Health Evaluation (APACHE) II score in the prognosis of patients with acute PQ poisoning. A total of 194 patients with acute PQ poisoning, hospitalized between April 2012 and January 2014 at the First Affiliated Hospital of P.R. China Medical University (Shenyang, China), were selected and divided into survival and mortality groups. Logistic regression analysis, receiver operator characteristic (ROC) curve analysis and Kaplan-Meier curve were applied to evaluate the values of urine paraquat (PQ) concentration, dose of poison, arterial blood lactate and (APACHE) II score for predicting the prognosis of patients with acute PQ poisoning. Initial urine PQ concentration (C0), dose of poison, arterial blood lactate and APACHE II score of patients in the mortality group were significantly higher compared with the survival group (all P<0.05). Logistic regression analysis revealed that C0, dose of poison and arterial blood lactate correlated with mortality risk of acute PQ poisoning (all P<0.05). ROC curve analysis suggested that the areas under the curve (AUC) values of C0, dose of poison, arterial blood lactate and APACHE II score in predicting the mortality of patients within 28 days were 0.921, 0.887, 0.808 and 0.648, respectively. The AUC of C0 for predicting early and delayed mortality were 0.890 and 0.764, respectively. The AUC values of urine paraquat concentration the day after poisoning (Csec) and the rebound rate of urine paraquat concentration in predicting the mortality of patients within 28 days were 0.919 and 0.805, respectively. The 28-day survival rate of patients with C0 ≤32.2 µg/ml (42/71; 59.2%) was significantly higher when compared with patients with C0 >32.2 µg/ml (38/123; 30.9%). These results suggest that the initial urine PQ concentration may be the optimal index for predicting the prognosis of patients with acute PQ poisoning. Additionally, dose of poison, arterial blood lactate, Csec and rebound rate also have referential significance.

An Effective Machine Learning Approach for Prognosis of Paraquat Poisoning Patients Using Blood Routine Indexes

The early identification of toxic paraquat (PQ) poisoning in patients is critical to ensure timely and accurate prognosis. Although plasma PQ concentration has been reported as a clinical indicator of PQ poisoning, it is not commonly applied in practice due to the inconvenient necessary instruments and operation. In this study, we explored the use of blood routine indexes to identify the degree of PQ toxicity and/or diagnose PQ poisoning in patients via machine learning approach. Specifically, we developed a method based on support vector machine combined with the feature selection technique to accurately predict PQ poisoning risk status, then tested the method on 79 (42 male and 37 female; 41 living and 38 deceased) patients. The detection method was rigorously evaluated against a real-world data set to determine its accuracy, sensitivity and specificity. Feature selection was also applied to identify the factors correlated with risk status, and the results showed that there are significant differences in blood routine indexes between dead and living PQ-poisoned individuals (p-value < 0.01). Feature selection also showed that the most important correlated indexes are white blood cell and neutrophils. In conclusion, the toxicity or prognosis of PQ poisoning can be preliminarily ascertained by blood routine testing without PQ concentration data, representing an additional tool and innovative approach to assess the prognosis of PQ poisoning.

Prognosis and survival analysis of paraquat poisoned patients based on improved HPLC-UV method

Paraquat (PQ) has caused deaths of numerous people around the world. In order to assess the lethal plasma concentration, the patients who acquired acute PQ intoxication were analyzed by plasma concentration monitoring. The plasma PQ concentrations were determined by high performance liquid chromatography (HPLC) which used 5-bromopyrimidine as internal standard and trichloroacetic acid-methanol (1:9) as protein precipitant. The liver, kidney and coagulation function were determined by automatic biochemical analyzer. According to plasma PQ concentration, 90 patients were divided into four groups: trace PQ group (<50ng/mL), low PQ group (<1000ng/mL), medium PQ group (1000-5000ng/mL) and high PQ group (>5000ng/mL). The clinical data from the four groups was statistically analyzed. The results showed the developed HPLC methods exhibited a high degree of accuracy and good linearity within 50-25000ng/mL (R=0.9998). The Spearman's correlation analysis showed PQ concentration had a strong relationship to total bilirubin, direct bilirubin, aspartic transaminase, urea nitrogen, prothrombin time, prothrombin activity, and international normalized ratio (P<0.01). The cured or survival PQ poisoned patients among the trace PQ group, the low PQ group, the medium PQ group, and the high PQ group were 19/19 (100%), 19/21 (90.47%), 11/25 (44.0%), and 0/25 (0%) respectively. The mean hospital days were (10.37±8.04), (18.76±12.06), (16.76±14.44), and (4.04±5.41) days respectively. The Cox regression analysis indicated that plasma PQ concentration was highly related to prognosis (P<0.05). In conclusion, no patient presenting with a PQ concentration over 5000ng/mL survived. The plasma PQ level is related to liver, kidney and coagulation function, which can be used as an important clinical index to judge the prognosis of PQ poisoned patients.

CHEMICAL COMPOUNDS

Paraquat (PubChem CID: 15938), 5-bromopyrimidine (PubChem CID: 78344), acetonitrile (PubChem CID: 6342), sodium dihydrogen phosphate (PubChem CID: 23672064), sodium heptanesulfonate (PubChem CID: 23672332), methylprednisolone (PubChem CID: 6741), cyclophosphamide (PubChem CID: 2907).

Hyperamylasemia as an Early Predictor of Mortality in Patients with Acute Paraquat Poisoning

Background

Paraquat (PQ) is a non-selective and fast-acting contact herbicide which has been widely used in developing countries. Hyperamylasemia was reported in patients with PQ poisoning. This study investigated the predictive value and clinical characteristics of hyperamylasemia in patients with PQ poisoning.

Material/Methods

This study included 87 patients with acute PQ poisoning admitted from July 2012 to May 2015. Data were collected from medical records. Receiver operating characteristic (ROC) analysis was conducted to analyze the discriminatory potential of serum amylase with respect to 90-day mortality.

Results

Of 87 patients, 29 patients had elevated serum amylase. We found that serum amylase was significantly higher among patients with AKI than those with non-AKI (p<0.001), and was an independent predictor of mortality (hazard ratio [HR]=3.644; 95% [CI], 1.684–7.881; p=0.001). The area under the ROC curve for the serum amylase (area under curve [AUC]=0.796; 95% [CI], 0.690–0.903) had a better discriminatory potential than plasma PQ concentration (0.698;0.570–0.825) or urinary PQ concentration (0.647;0.514–0.781) in predicting 90-day mortality.

Conclusions

Hyperamylasemia is a valuable early predictor of 90-day mortality in PQ poisoning.

The significance of serum uric acid level in humans with acute paraquat poisoning

Hyperuricemia is a strong and independent predictor of all-cause mortality in cardiovascular disease and has been found to play a role in diseases exacerbated by oxidative stress and inflammation. This study aimed to evaluate whether serum uric acid (UA) level is an indicator of outcome in patients with acute paraquat poisoning. A total of 205 subjects who had attempted suicide by oral ingestion of paraquat were admitted to the emergency room between January 2009 and June 2014. Initial serum UA level and other laboratory parameters were measured. A total of 66 patients died during the 30 days after admission, corresponding to a 32.2% cumulative incidence of mortality. UA levels were higher in non-survivors than survivors (P < 0.001) and 30-day mortality increased with increasing baseline serum UA level (P < 0.001). In a prediction analysis for 30-day mortality, the serum UA level had a cut-off concentration of 284 µmol/L in female patients and 352 µmol/L in male patients. Multivariate Cox proportional hazards regression analyses showed that white blood cell counts and UA were independent prognostic factors. In conclusion, we showed that serum UA may be an independent predictor of 30-day mortality in patients with paraquat poisoning.

Diagnostic and therapeutic approach for acute paraquat intoxication

Paraquat (PQ) has known negative human health effects, but continues to be commonly used worldwide as a herbicide. Our clinical data shows that the main prognostic factor is the time required to achieve a negative urine dithionite test. Patient survival is a 100% when the area affected by ground glass opacity is <20% of the total lung volume on high-resolution computed tomography imaging 7 days post-PQ ingestion. The incidence of acute kidney injury is approximately 50%. The average serum creatinine level reaches its peak around 5 days post-ingestion, and usually normalizes within 3 weeks. We obtain two connecting lines from the highest PQ level for the survivors and the lowest PQ level among the non-survivors at a given time. Patients with a PQ level between these two lines are considered treatable. The following treatment modalities are recommended to preserve kidney function: 1) extracorporeal elimination, 2) intravenous antioxidant administration, 3) diuresis with a fluid, and 4) cytotoxic drugs. In conclusion, this review provides a general overview on the diagnostic procedure and treatment modality of acute PQ intoxication, while focusing on our clinical experience.

Fluorescence detecting of paraquat using host-guest chemistry with cucurbit[8]uril

Paraquat (PQ) is one of the most widely used herbicides in the world, which has a good occupational safety record when used properly. While, it presents high mortality index after intentional exposure. Accidental deaths and suicides from PQ ingestion are relatively common in developing countries with an estimated 300,000 deaths occurring in the Asia–Pacific region alone each year, and there are no specific antidotes. Good predictors of outcome and prognosis may be plasma and urine testing within the first 24 h of intoxication. A fluorescence enhancement of approximately 30 times was seen following addition of PQ to a solution of the supramolecular compound 2MB@CB[8], which comprised two methylene blue (MB) molecules within one cucurbit[8]uril (CB[8]) host molecule. The fluorescence intensity was linearly proportional to the amount of PQ added over the concentration range 2.4 × 10⁻¹⁰ M–2.5 × 10⁻⁴ M. The reaction also occurred in living cells and within live mice.