Comparative analysis of ingestion assessment methods in paraquat-poisoned patients

Abstract

Objective

This study investigated clinical methodologies for estimating ingested pesticide volume and evaluated their accuracy in acute oral poisonings.

Methods

The evaluation of poison ingestion was divided into accurate evaluation, empirical evaluation, and simulated ingestion evaluation. Statistical analysis was conducted using the data of 60 cases of acute oral paraquat poisonings (PQP) in our hospital from the aspect of empirical evaluation, simulated ingestion evaluation, blood toxicant test, and prognosis. Moreover, the measurements of oral capacity and simulated dose were compared in the general population based on sex, age, height, weight, and season.

Results

A significant difference was observed between the amount based on empirical evaluation and that based on simulated ingestion evaluation (P < 0.05). In simulated ingestion evaluation, the amount in males was significantly higher than that in females, and the amount in males was correlated with blood toxicant concentration and prognosis. No statistical difference in oral capacity was observed in the general population based on age, season, and body weight (P > 0.05). Both the maximum and normal mouthfuls in males were statistically different from those in females (P < 0.05, P < 0.05). A statistical difference in oral capacity (maximum mouthful and normal mouthful) was observed among various height groups (P < 0.01, P < 0.05), indicating that the higher the height, the larger the oral capacity.

Conclusions

Only 7.69% of the cases were allowed for an accurate dose evaluation. The ingested poison dose based on empirical and simulated ingestion evaluation were correlated with blood toxicant concentrations and prognosis in patients with PQP. Factors, such as sex and height, should be considered by physicians in empirical evaluation. It is still a great clinical challenge to accurately evaluate the ingested dose of liquid pesticides.

Introduction

Acute oral intoxication accounts for over 55% of pesticide poisoning cases [1]. Liquid formulations dominate poisoning incidents, particularly in acute organophosphate and paraquat (PQ) poisonings [2, 3]. Since PQ concentration critically influences its toxicity, and rapid distribution to pulmonary, hepatic, and renal tissues causes progressive fibrosis and multi-organ failure [4, 5], even minimal exposures may prove fatal. Current PQ management strategies—including hemoperfusion, continuous renal replacement therapy, immunosuppression, and antioxidant regimens—heavily rely on patient-reported ingestion volume [6, 7]. Consequently, early dosage estimation remains paramount for treatment selection and prognosis stratification in PQ poisoning.

Although plasma PQ quantification, Severity Index of Paraquat Poisoning (SIPP), and prognostic nomograms exhibit mortality predictive value [8–10], these approaches demonstrate inherent limitations: plasma measurements remain cost-prohibitive and inaccessible, while available models primarily serve critically ill cohorts rather than minimally exposed or pre-symptomatic patients. Clinically, most patients can only report ingesting "one or several mouthfuls"—a descriptor subject to substantial anthropometric variability without standardized bedside conversion methodologies. While previous investigations characterized buccal capacity through craniofacial morphometrics [11, 12], these physiological parameters remain unintegrated into pragmatic poison volume assessment.

In this study, statistical analysis was conducted using the data sourced from acute oral PQP in the aspect of empirical evaluation, simulated ingestion evaluation, blood toxin test, and prognosis. This study provides a reference and basis for any studies about poison ingestion evaluation methods aiming to produce a more accurate ingestion evaluation and prognosis.

Materials and methods

Subjects

Patients with acute oral PQP who received individualized comprehensive treatment regimens in the emergency department of our hospital were searched.

Inclusion criteria: (1) acute oral PQP, (2) duration from ingestion to consultation, and (3) age > 14 years old.

Exclusion criteria: (1) unintended ingestion; (2) unconscious and unable to cooperate to reproduce the ingestion; (3) patients with missing teeth, oral tumors, or obvious severe oral deformities; (4) poisoning with mixed pesticides; and (5) patients who refuse to receive individualized comprehensive treatment regimens.

Additionally, this study enrolled 60 healthy volunteers without oropharyngeal pathologies recruited during routine medical examinations, excluding individuals with dysphagia, neurological deficits, or developmental craniofacial abnormalities.

Treatments

Gastric lavage, catharsis to prevent poison absorption, hemoperfusion to improve poison excretion, medications with glucocorticoids, immunosuppression inhibitors and antioxidants to inhibit inflammation and organ function, as well as supporting treatments were given to patients with acute oral PQP immediately after admission. Generally, an indwelling dual-lumen catheter (Guangdong Baihe Medical Technology Co., Ltd., Guangdong, China) was inserted by femoral vein access at 1–2 h after admission, and 3000 IU low-molecular weight heparins were given for anticoagulation before hemoperfusion using an HA 330 perfusion device (Jafron Biomedical Co., Ltd., Zhuhai, China) at a flow rate of 180–200 mL/min for 2 h. The interval of hemoperfusions was 6–8 h, and its number was dependent on blood PQ concentrations.

Study design and sample size

This single-center exploratory cohort study consecutively screened eligible adults with acute oral paraquat poisoning presenting to the Second Hospital of Hebei Medical University between August 2024 and February 2025. All 60 patients completing the dose-evaluation protocol during this prespecified timeframe were included for final analysis. No prospective power calculation was performed due to recruitment constraints dictated by case incidence and study duration parameters.

Measurements

In the clinical evaluation of poison ingestion, three methods were used: evaluation, evaluation by ingestion reproduction, and precise evaluation. For patients with acute oral PQP in this study, physicians quickly completed a precise evaluation or empirical evaluation based on medical history immediately after admission. For patients who were evaluated empirically, a simulated ingestion evaluation was completed by two trained physicians within 8 h of admission.

• 3.1Accurate dose measurement (ADM): The ingested amount was determined objectively (to mL or g) when reliable information was available at admission, based on the container’s scale and a consistent history (e.g., ingestion of an entire or half bottle with no spill, and direct measurement of the remaining volume). These cases were documented as precise dose assessments.
• 3.2Empirical dose estimation (EDE): When ADM was unfeasible, clinicians estimated ingested volumes immediately post-admission by integrating: patient-reported intake descriptors (typically ‘one or several mouthfuls’), container specifications, and scene observations. Anthropometric parameters including sex, height, and body habitus were considered despite lacking standardized quantification protocols, with all assessments documented in medical records.

Twenty board-certified physicians (associate professors or attending physicians) with > 10 years' clinical toxicology experience participated. Pre-trial training comprised: (1) a standardized 90- to 120-min workshop on paraquat formulations and container volumetrics; (2) calibration exercises establishing measured water volumes for mouthful descriptors; and (3) distribution of validated pocket references (container catalogues/volume anchors) for bedside use. Certification required completion of didactic and practical assessments.

Per Fig. 1 questionnaires, > 80% of clinicians accounted for height and weight influences during assessments, hypothesizing positive correlations between anthropometric indices and oral volume capacity.

• 3.3Simulated ingestion evaluation (SIE; formerly “reproduction evaluation”): SIE is a standardized bedside procedure intended to approximate the patient’s single mouthful volume at the time of poisoning. It was performed within 8 h of admission by two trained staff.
• 3.4Procedure and materials

Fig. 1.

...

Materials: bottled water at room temperature and a calibrated graduated cylinder.

Patient instruction: patients were asked to take a mouthful of water that, in their judgment, matched the amount of paraquat ingested, without swallowing, and then expel it into the cylinder.

Repetition and recording: the procedure was repeated three times. Each reading was recorded independently by two observers; the mean of the three volumes was used as the SIE value. If the two observers’ readings differed by > 5 mL, the volume was re‑read and the trial repeated.

Standardization: testing was conducted with the patient seated, using the same bottle and cylinder throughout, and avoiding talking or salivation stimulation between trials.

Safety and exclusions.

Patients were instructed not to swallow the test water. SIE was not performed in individuals who were unable to cooperate or had exclusion conditions (e.g., severe oral lesions/deformities). The use of water avoided the risks associated with commercial paraquat formulations, which contain emetics and have distinct taste/viscosity; this difference is acknowledged as a source of potential bias.

• 3.5Distinction from oral capacity testing.

SIE targets the patient’s perceived single mouthful volume at the index event. It differs from the oral capacity measurements conducted in the general population, which quantify maximum, normal, and minimum mouthful volumes under standardized conditions for physiological characterization.

Collection of clinical data

General information was collected from the included patients with acute oral PQP, including sex, age, duration from poison ingestion to admission (2–6 h in all the cases), blood PQ concentration at admission (blood was taken within 20 min after admission), and prognosis (recovering or death).

Measurement of oral capacity in the general population

• 5.1The same population was tested in spring (17 ℃) and autumn (7 ℃).
• 5.2Procedure: Recording forms were recorded, the participants were gathered, and the purpose, method, and procedure were introduced by a test host. Afterwards, all participants took six mouthfuls of mineral water from prepared bottles with a maximum, normal, and minimum mouth opening at ingestion 1, 2, and 3, respectively. In ingestion 4–6, the participants were asked to assume that they were drinking pesticide PQ to simulate the scene where PQ was taken, and the readings were recorded as simulated ingestion 1, 2, and 3. The participants were asked at each ingestion not to swallow it down and to spit it out into a measuring cup. The readings at each ingestion were taken by two trained personnel, and the average was recorded.
• 5.3General information, such as sex, age, weight, and height, was collected from the general population.

Statistical analysis

Statistical analysis was performed using SPSS 22.0 software. Measurement data in normal distribution were expressed as mean ± standard deviation ($\overline{x}$±s), and the inter-group comparisons were performed by t-test or analysis of variance. Measurement data not in normal distribution were expressed as the median (quartile) [M (Q_L, Q_U)], and the inter-group comparisons were performed by rank-sum test. Enumeration data were expressed as the number (% percent) of cases, and P < 0.05 was considered statistically significant.

Results

General information

In this study, 65 patients with PQP were included, of which five patients had a precise evaluation of poison ingestion, including three cases of 200 mL of oral PQ (a full bottle) and two cases of 100 mL of oral PQ (half bottle). The remaining 60 patients with acute oral PQP impossible for an accurate evaluation of poison ingestion were included in this study. They were all Han and residents in Shijiazhuang city or surrounding cities and counties. Thirty males and 30 females aged 32.82 ± 10.96 years old were included, with a duration from poison ingestion to admission of 4 (2, 6) h and a blood PQ concentration of 6.8 (3.83, 14.33) mg/L. The healthy cohort comprised 60 participants (29 female, 31 male) with a mean age of 33.01 ± 9.84 years. Intergroup comparisons confirmed no significant demographic differences between sexes (sex distribution: P = 0.855; age: P = 0.921).

Comparison of empirical evaluation and simulated ingestion evaluation

• 2.1In patients with acute oral PQP, 3–120 mL was produced by empirical evaluation, with an average of 55.28 ± 26.85 mL, and 2–90 mL was produced by simulated ingestion evaluation, with an average of 37.23 ± 16.78 mL, indicating a significant difference (T = 4.414,P < 0.001).
• 2.2Comparison between males and females by empirical evaluation

Oral volumetric measurements demonstrated ranges of 20–100 mL (55.83 ± 21.18 mL) in males (n = 30) and 3–120 mL (54.77 ± 31.90 mL) in females (n = 30), with no significant sex-based difference (t = 0.160, p = 0.874).

• 2.3Comparison between males and females by simulated ingestion evaluation

Volumetric analysis revealed significant sex-based differences (t = 2.907; p = 0.005), with males (n = 30) demonstrating higher mean ingestion volumes (43.17 ± 18.70 mL, range 16 to 90 mL) versus females (n = 30: 31.30 ± 12.26 mL, range 2–90 mL).

Correlation between poison ingestion by simulated ingestion evaluation and empirical evaluation and blood PQ concentrations and prognosis indices

Regarding prognosis, there was a correlation for poison ingestion by empirical evaluation and simulated ingestion evaluation and blood concentrations, with a statistically significant coefficient of correlation of r = 0.359 (P < 0.05), r = 0.395 (P < 0.001), and r = −0.468 (P < 0.05), respectively.

Comparison of oral capacity by sex, age, season, weight, and height in the general population

Comparison of oral capacity by sex in the general population

For both maximum and normal mouthfuls, a statistically significant difference was seen between males and females (P < 0.05). However, no significant difference in oral capacity was found when the poison was ingested consecutively through simulation (P > 0.05). The details are shown in Table 1.

Table 1.

Comparison of oral capacity by sex

Sex	N	Maximum mouthful	Normal mouthful	Small mouthful	First mouthful	Second mouthful	Third mouthful
Male	30	88.57 ± 27.28	47.21 ± 23.21	20.42 ± 12.36	42.28 ± 31.01	29.57 ± 15.89	28.79 ± 15.17
Female	30	61.88 ± 11.43	30.31 ± 10.42	15.69 ± 7.34	37.44 ± 16.89	29.56 ± 11.56	30.94 ± 19.60
t`		−2.582	−2.055	−0.809	−0.21	−0.46	−0.251
P		0.010	0.040	0.419	0.983	0.645	0.802

Comparison of oral capacity by age in the general population

For minimum mouthfuls, a significant difference was seen among different age groups (P < 0.05), while no significant difference was seen for both maximum and normal mouthfuls (P > 0.05). The details are shown in Table 2.

Table 2.

Comparison of oral capacity and age

Age (岁)	N	Maximum mouthful	Normal mouthful	Small mouthful
20 ~	15	79.17 ± 27.42	43.50 ± 20.87	20.88 ± 11.41
30 ~	15	67.08 ± 16.85	30.25 ± 13.81	13.42 ± 5.66
40 ~	15	103.40 ± 29.24	47.53 ± 15.82	32.20 ± 13.25
50–60	15	90.27 ± 15.29	63.89 ± 14.62	39.06 ± 13.14
t`		−1.086	−1.879	−1.972
P		0.278	0.060	0.049

Comparison of oral capacity by season in the general population

For maximum, normal, and minimum mouthfuls, no significant difference was found among different seasons (P > 0.05). The details are shown in Table 3.

Table 3.

Comparison of oral capacity by season

Season	N	Maximum mouthful	Normal mouthful	Small mouthful
Autumn	60	73.30 ± 25.54	34.69 ± 15.15	15.46 ± 8.44
Spring	60	61.77 ± 19.73	32.46 ± 10.33	14.76 ± 4.72
t`		−0.136	−0.026	−0.104
P		0.210	0.979	0.917

Comparison of oral capacity by weight in the general population

For minimum mouthfuls, a significant difference was seen among different weight groups (P < 0.05), while no significant difference was seen for both maximum and normal mouthfuls (P > 0.05). The details are shown in Table 4.

Table 4.

Comparison of oral capacity by weight

Weight (kg)	N	Maximum mouthful	Normal mouthful	Small mouthful
50 ~	20	83.45 ± 22.76	47.81 ± 19.85	21.63 ± 10.66
60 ~	20	90.72 ± 13.65	61.00 ± 13.65	35.18 ± 16.55
70–80	20	109.10 ± 29.39	68.20 ± 18.90	47.40 ± 17.83
t`		−1.086	−1.879	−1.972
P		0.278	0.060	0.049

Comparison of oral capacity by height in the general population

For both maximum and normal mouthfuls, a significant difference was seen among different height groups (P < 0.05), while no significant difference was seen for minimum mouthfuls (P > 0.05). The details are shown in Table 5.

Table 5.

Comparison of oral capacity by height

Height	N	Maximum mouthful	Normal mouthful	Small mouthful
150 ~ 160 cm	20	76.58 ± 23.38	37.89 ± 18.62	17.83 ± 8.10
161 ~ 170 cm	20	78.67 ± 14.07	42.80 ± 9.655	17.84 ± 8.85
171 ~ 180 cm	20	92.00 ± 20.49	51.17 ± 15.55	19.00 ± 8.03
t`		−2.611	−2.207	0
P		0.009	0.027	1.000

Discussion

Acute oral pesticide poisoning constitutes a global public health threat in developing nations, characterized by complex rapidly progressive clinical courses and high mortality without timely intervention [13]. Ingested volume critically influences poisoning severity and prognosis—particularly for high-fatality pesticides like paraquat (PQ). Accurate quantification remains challenging: international studies report pesticide ingestion volumes [14–17], but omit methodological specifics. Objective patient recall is often compromised by psychological distress, container loss, or spillage. Although serum/urine toxicant levels provide superior prognostic value [18–20], clinical utility is limited by variable presentation delays, toxicokinetic heterogeneity, testing availability, and costs [19–22].

The methods of poison ingestion evaluation were divided into empirical evaluation, simulated ingestion evaluation, and accurate evaluation. In this study, 65 patients with PQP were included, of which only five were possible for accurate evaluation, and the remaining were unable to provide the precise dose of the poison. For the latter patients, empirical evaluation or simulated ingestion evaluation was required. In this study, the amount of ingested poison based on empirical evaluation was significantly greater than that based on simulated ingestion evaluation (P < 0.05), and the amount based on simulated ingestion evaluation in males was significantly higher than that in females (P < 0.05). The marked divergence between empirically estimated and reproduced ingestion volumes necessitates nuanced analysis. Empirical overestimation likely stems from clinicians’ defensible caution when managing high-mortality toxins like paraquat, reflecting emergency medicine’s precautionary principle: when precise dose determination proves infeasible yet critically informs prognosis, protocols prioritize maximal intervention. Indeed, our physician survey identified 20–30 mL as a common empirical "mouthful" baseline—values notably exceeding volumes measured in healthy cohorts. Simulated ingestion evaluation, conversely, may underestimate true ingestion due to irreconcilable methodological constraints. Commercial paraquat formulations contain viscous emetics (e.g., ZnSO₄) and potent odorants that provoke immediate gagging/vomiting during actual ingestion—physicochemical properties absent in water-based simulation trials. Furthermore, recall accuracy may be compromised by median 4-h delays to clinical assessment. Psychological avoidance mechanisms (evidenced by greater variance among females) could additionally suppress reproduced volumes. This dual discrepancy—clinically prudent overestimation versus methodologically constrained underestimation—accounts for the observed variance while retaining both methods’ prognostic relevance, given survival’s persistent dependence on ingested dose. A questionnaire involving 20 on-duty physicians suggested that sex, age, and mouth opening were less considered in the empirical evaluation. Although height and weight were often considered, there was a lack of specific standards, so the accuracy was influenced by many uncertain factors.

It was shown that the maximum oral capacity was moderately positively correlated with height and weight and was slightly positively correlated with mouth opening and chewing efficiency [23]. The maximum oral capacity in this context refers to the maximum water volume that a subject can hold in his/her mouth at one time. Different from the maximum oral capacity, the influencing factors in empirical evaluation are required to be further studied. In simulated ingestion evaluation, the accuracy was influenced by the following factors. Although the patients were asked to try their best to recall and reproduce the original scene, commercial PQ solutions contain emetics and odorants, and their taste and viscosity are apparently different from those of mineral water. Furthermore, most of them attempted to commit suicide, so the original emotions and moods were difficult to reproduce.

Oral capacity demonstrated significant correlation with height, yet the translational relevance for clinical dose estimation demands careful contextualization. Maximum oral capacity varied substantially by stature: 78.5 mL at 170 cm versus 63.2 mL at 150 cm (24.2% difference). Theoretically, this variation could confound mortality risk assessment in paraquat poisoning, where 10 mL ingestion elevates fatality probability ≥ 20%. However, two intrinsic factors limit clinical impact: (1) physiological reflexes (gagging, spillage) reduce actual intake to 30–50% of maximum oral capacity during genuine ingestion events. (2) Management protocols adopt universal intervention thresholds (e.g., gastric lavage + hemoperfusion for > 10 mL regardless of height) in accordance with precautionary principles. Consequently, while stature corrections may enhance toxicokinetic models, their utility in emergent triage remains marginal against standardized therapeutic imperatives. Future investigations should evaluate whether incorporating anthropometric parameters quantitatively improves predictive accuracy when integrated with machine learning algorithms versus conventional clinical assessment alone.

For empirical evaluation, no difference between males and females was observed. However, in simulated ingestion evaluation, the amount in males was significantly higher than that in females, and the amount in males was closer to that by empirical evaluation and may objectively reflect the true value. As shown in the simulation experiment, a mouthful in males and females was 10–130 mL and 5–80 ml, respectively. Both the maximum and normal mouthfuls in males were higher than those of females. Males have a higher mouthful, which may be one of the reasons for their higher mortality due to pesticide poisoning [24]. In a prospective study on organophosphate poisoning, both blood toxicant concentration and mortality in males were higher than those in females [25], which were presumably related to their higher oral capacity; thus, a larger amount of ingested poison. In a continuous ingestion simulation, sex had no effect on the simulated parameters, which may be related to the clear intention of ingestions. In very few females, the amounts obtained in reproduction experiments were significantly lower than the previously estimated amounts, and the outcomes were obviously inconsistent with the prognosis, which may be related to the avoidance mentality of females and inaccurate reproduction due to oral mucosal damage caused by PQ. Therefore, the prognosis should be cautiously evaluated when using reproduction experiments.

The significant correlation between PQ ingestion volume and serum concentration holds critical prognostic implications, warranting mechanistic contextualization within PQ’s biphasic toxicity profile [26]. Higher PQ exposure escalates mortality risk through dual pathogenic pathways: immediate multi-organ dysfunction caused by acute oxidative stress, and delayed pulmonary fibrosis from progressive tissue accumulation. Prognostic interpretation remains complex; however, as mortality exhibits substantial interindividual variation even at comparable serum concentrations [27]. Clinically, unconscious presentation precludes accurate ingestion documentation in many cases. Furthermore, neither ingested dose nor serum levels consistently predict individual outcomes due to confounding by absorption kinetics, comorbidities, treatment latency, and therapeutic responsiveness [28]. Consequently, while quantitative exposure assessment provides vital initial risk stratification, optimizing prognostication necessitates concurrent evaluation of time-dependent treatment responses and individual trajectory monitoring.

In poison ingestion evaluation in patients with PQP, regardless of sex, the amounts obtained by empirical evaluation were significantly higher than those obtained by simulated ingestion evaluation. In both empirical and simulated ingestion evaluation, poison ingestion was correlated with blood toxicant concentration and prognosis. Both methods are prognosis-indicating and can be used as a basis to determine the ingested PQ dose. The prognosis indication of ingested doses may be related to higher mortality due to PQ, as demonstrated in a lethal oral dose of 1–3 g [29, 30] and one mouthful of commercial 20% concentrated solution [31, 32]. However, for low to moderately toxic liquid pesticides, a higher ingested dose may be required to cause death. The correlation between the ingested dose and prognosis needs to be further studied.

Oral capacity is a relevant factor in poison ingestion evaluation, whereas due to different craniofacial structures in populations of various ethnic groups, regions, sex, stomatological anatomy, and oral capacity are inconsistent [33, 34]. There are fewer studies about the description of oral capacity and its correlation with sex, age, height, weight, and season. In this study, the statistical analysis of oral capacity by season, temperature, height, weight, and age found that age, weight, season, and external temperature had no effects on oral capacity, while height had (maximum mouthful and normal mouthful) because of the significant difference observed among different height groups (P < 0.01, P < 0.05), indicating that the higher the height, the larger the oral capacity. For empirical evaluation, the influencing factors should be considered. An early and accurate poison ingestion evaluation will help determine the individualized treatment regimens in an early stage; thus, this may enhance the cure rate, avoid excessive medical treatments, and reduce related side effects.

Several study limitations warrant acknowledgment. First, our sample size (n = 60 PQ patients) was restricted by clinical availability without a priori power analysis; we consequently report effect sizes with 95% CIs to indicate estimation precision. Second, the single-center Han Chinese cohort limits generalizability. Craniofacial morphology, oral capacity, and ingestion behaviors demonstrate documented ethnic variation—potentially impacting both actual ingestion volumes and simulated ingestion evaluation performance. Commercial pesticide formulations and healthcare access also differ regionally. Importantly, our control oral-capacity data derived from the same demographic, necessitating validation across diverse populations. Methodologically, empirical estimation relies on subjective patient reports that may inflate volumes due to recall bias or psychological distress. Although simulated ingestion evaluation mitigates some subjectivity, post-intoxication recall inaccuracy during chaotic scenarios remains problematic. Environmental testing revealed non-significant oral-capacity variations between autumn (mean 7 °C) and spring (17 °C) cohorts, supporting seasonal robustness for emergency assessments. However, extreme conditions (< 0 °C or heat stress) require further investigation. Collectively, these constraints underscore the need for multicenter validation incorporating broader ethnic representation, standardized toxicant formulations, and objective dose-verification methods.

Accurately assessing ingested doses of liquid pesticides remains a formidable clinical challenge due to methodological irreproducibility and contextual constraints. Our study reveals that current approaches permit precise quantitation in only 7.69% of cases, highlighting profound limitations in clinical toxicology. The empirical method suffers from subjectivity without standardization of physician decision protocols or weight assignment for influencing factors. Similarly, simulated ingestion evaluation cannot replicate the physicochemical properties (taste/viscosity) of commercial pesticides or recreate the psychological/environmental conditions of actual intoxication events, significantly limiting dose reproducibility. Both methods demonstrate utility for low-lethal-dose agents like paraquat (fatal at ≤ 10 mL), but their prognostic accuracy remains unvalidated for pesticides requiring > 30 mL lethality thresholds. Sex and height exert clinically quantifiable effects on accuracy; future development should prioritize covariate-adjusted formulas integrating oral capacity for individualized assessment. Immediate improvements warrant standardized volumetric vomitus collectors with clinician protocols, while mathematical models incorporating key covariates (recalled volume, anthropometrics) could enable practical risk stratification in primary hospitals lacking toxicology testing. Multicenter studies across diverse pesticides and populations remain essential to reconcile these measurement gaps—ultimately transforming poison evaluation from observational estimation into objective metrology.

Author contributions

Y. L.J was involved in the design and analysis of the study, N.M and M.W carried out the measurement and collection of data, and H.B.G and Y.P.T analysed the results and statistical analysis.

Funding

Clinical study on the treatment of acute organophosphorus pesticide poisoning with comparable doses of iodophosphidine. Project No.:20211185.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the Research Ethics Committee of the Second Hospital of Hebei Medical University (Approval Letter No.: 2024-R539). All patients involved in this study consented to the publication of the article.

Competing interests

The authors declare no competing interests.