Serum paraquat concentration detected by spectrophotometry in patients with paraquat poisoning

BACKGROUND:

Paraquat (PQ) is a world-wide used herbicide and also a type of common poison for suicide and accidental poisoning. Numerous studies have proved that the concentration of serum PQ plays an important role in prognosis. Spectrophotometry, including common spectrophotometry and second-derivative spectrophotometry, is commonly used for PQ detection in primary hospitals. So far, lack of systematic research on the reliability of the method and the correlation between clinical features of patients with PQ poisoning and the test results has restricted the clinical use of spectrophotometry. This study aimed to evaluate the reliability and value of spectrophotometry in detecting the concentration of serum PQ.

METHODS:

The wavelengths for detecting the concentration of serum PQ by common and second-derivative spectrophotometry were determined. Second-derivative spectrophotometry was applied to detect the concentration of serum PQ. The linear range and precision for detection of PQ concentration by this method were confirmed. The concentration of serum PQ shown by second-derivative spectrophotometry and HPLC were compared in 8 patients with PQ poisoning. Altogether 21 patients with acute poisoning 4 hours after PQ ingestion treated in the period of October 2008 to September 2010 were retrospectively reviewed. The patients were divided into higher and lower than 1.8 μg/mL groups based on their concentrations of serum PQ measured by second-derivative spectrophotometry on admission. The severity of clinical manifestations between the two groups were analyzed with Student''s t test or Fisher''s exact test.

RESULTS:

The absorption peak of 257 nm could not be found when common spectrophotometry was used to detect the PQ concentration in serum. The calibration curve in the 0.4–8.0 μg/mL range for PQ concentration shown by second-derivative spectrophotometry obeyed Beer''s law with r=0.996. The average recovery rates of PQ were within a range of 95.0% to 99.5%, relative standard deviation (RSD) was within 1.35% to 5.41% (n=6), and the lower detection limit was 0.05 μg/mL. The PQ concentrations in serum of 8 patients with PQ poisoning shown by second-derivative spectrophotometry were consistent with the quantitative determinations by HPLC (r=0.995, P<0.0001). The survival rate was 22.2% in patients whose PQ concentration in serum was more than 1.8 μg/mL, and the incidences of acidosis, oliguria and pneumomediastinum in these patients were 55.6%, 55.6% and 77.8%, respectively. These clinical manifestations were different significantly from those of the patients whose PQ concentration in serum was less than 1.8 μg/mL (P<0.05).

CONCLUSIONS:

For common spectrophotometry, the wavelength at 257 nm was not suitable for detecting serum PQ as no absorbance was shown. Second-derivative spectrophotometry was reliable for detecting serum paraquat concentration. Serum PQ concentration detected by second-derivative spectrophotometry could be used to predict the severity of clinical manifestations of patients with PQ poisoning, and PQ content higher than 1.8 μg/mL 4 hours after ingestion could be an important predictive factor for poor prognosis.KEY WORDS: Spectrophotometry, Derivative spectrophotometry, Paraquat, Poisoning, Serum, Concentration     

Prediction of prognosis in acute paraquat poisoning using severity scoring system in emergency department

Objective. The aim of this study was to validate and compare the performance of serum paraquat level, severity index of paraquat poisoning (SIPP), Acute Physiology And Chronic Health Evaluation II (APACHE II), modified Simplified Acute Physiology Score II (MSAPS II), and modified Expanded Simplified Acute Physiology Score II (MSAPS IIe) calculated immediately after arrival on emergency department (ED) for assessing the mortality of acute paraquat poisoning. Methods. A retrospective study design was employed with the main outcome measure being mortality from year 2001 to 2010. MSAPS II and MSAPS IIe were employed in that assessment of the 24-hour urine output were not included. The performance of APACHE II, MSAPS II, MSAPS IIe, serum paraquat level and SIPP for prediction of mortality in acute paraquat poisoning were compared. Results. A total of 102 patients were enrolled in the study. The area under the ROC curve for APACHE II (0.800) was statistically lower than those for MSAPS II, MSAPS IIe, SIPP and serum paraquat (0.879, 0.893, 0.924,and 0.951, respectively). The Hosmer-Lemeshow goodness-of-fit test C statistic revealed that APACHE II, MSAPS II, MSAPS IIe and serum paraquat level showed good calibrations (chi-square 8.477 and p = 0.388, chi-square 4.614 and p = 0.798, chi-squared 5.301 and p = 0.725, chi-squared 1.009 and p = 0.985 respectively), but poor calibration for SIPP (chi-square 21.293 and p = 0.006). Conclusion. Serum paraquat level is still the most reliable prognosis factor in acute paraquat poisoning. But MSAPS II or MSAPS IIe calculated immediately after arrival on ED may be helpful to predict mortality in acute paraquat poisoning especially when hospital has no facility to measure serum paraquat level.     

百草枯中毒的肺部X线表现及临床价值

目的探讨百草枯中毒的胸部X线表现及其临床价值。方法回顾分析11例临床确诊为百草枯中毒的胸部X线影像学特征。结果病变时期的不同,导致了影像学表现的多样化,典型的影像学表现为肺门向肺内散在分布的斑点状片状阴影7例（63．64％）,粟粒状阴影4例（36．36％）以及克氏B线2例和磨玻璃状影1例。结论本病的胸部X线影像学表现不具有特征性,但认识其影像学表现结合临床综合分析,对百草枯中毒肺损伤的诊断与鉴别诊断具有重要意义。     

3例百草枯中毒患儿的护理

回顾分析血浆置换治疗3例百草枯中毒患儿的护理.护理要点包括:呼吸道、消化道、肾脏、肝脏的监测,在血浆置换过程中管道的护理与并发症的观察.本组2例好转出院,1例死亡.     

百草枯中毒的研究进展

随着百草枯(PQ)的广泛应用,PQ中毒事件数量逐年增加,已成为我国第二位的农药中毒事件。PQ对人有剧毒,中毒后致多脏器严重损害,病死率极高,其中毒机制尚不完全明确,氧自由基产生学说为大多数学者认可。PQ中毒暂无特效解毒药,临床上主要采取综合治疗的办法,如洗胃、导泻、吸附体内毒素、应用激素及免疫抑制剂、清除氧自由基、保护各脏器功能等,同时结合有效的血液净化手段,本文旨在对相关进展做一简要综述。     

百草枯中毒患者的抢救与护理12例

通过对12例百草枯中毒患者的抢救与护理,总结出血液灌流和综合护理的重要性。     

急性百草枯中毒患儿的综合救治与护理

目的:总结急性百草枯中毒患儿的救治与护理方法,为儿科临床工作提供借鉴和参考。方法:对我院2012年1月~2014年5月收治的89例急性百草枯中毒患儿的临床资料、治疗与护理措施进行回顾性分析和总结。结果:本组患儿救治成功73例,死亡1例,家属放弃治疗15例,最重要的死亡原因是急性肺损伤引起的肺纤维化。结论:通过对急性百草枯中毒患儿的综合救治与护理,达到了良好的治疗效果,但是由于国内尚无公认治疗指南,临床上应开展多中心、大样本研究以验证不同治疗方式的有效性。     

急性百草枯中毒的治疗进展

百草枯（paraquat,1,1-二甲基-4,4-联吡啶阳离子盐）,是目前应用最广泛的触灭型除草剂之一,动物属中等毒性,但对人的毒性却较高,成人估计致死量40mg／kg。百草枯中毒后可造成多个系统或器官损害,肺部最为严重,病死率极高,致病机制复杂且尚未完全明确,     

百草枯中毒肺部MSCT表现分析

目的总结百草枯中毒不同剂量、不同时期肺部MSCT表现特点。方法收集我院2012年1月~2014年12月64例百草枯中毒患者的临床及肺部MSCT资料,根据中毒剂量分为三组,分别是小剂量组(小于20 mg)12例,中剂量组(20~40 mg)36例,大剂量组(大于40 mg)16例;并根据病程在第1、3、7天(早期)、第15天(中期)和第30、90天(晚期)行多层螺旋CT肺部检查,对不同剂量不同病程患者的MSCT肺内表现及肺部并发症进行分析。结果百枯中毒肺部MSCT表现包括肺纹理增强、肺泡渗出、肺实变及肺纤维化。在中毒的不同时期有不同的表现,早期第1天时主要表现为肺纹理增强(26/49)、第3天以渗出为主(36/38),第7天则演变为以渗出(26/31)和实变(7/31)为主;中期(15 d)发展为渗出(18/22)、实变(10/22)和纤维化(10/22);晚期(30 d)表现为肺实变(8/14)、肺纤维化(11/14);晚期(90 d)转变为肺实变(2/6),肺纤维化(6/6)。不同剂量的中毒者也有不同的表现特点,其中小、中剂量组早期第1天以正常(11/33)或肺纹理增强(22/33)表现为主,大剂量组早期第1天即可以出现渗出改变(5/13);百草枯中毒可出现并发症,包括纵隔气肿(16/64)、胸腔积液(13/64)、胸膜增厚(14/64)、气胸(5/64)及支气管扩张(1/64)。结论不同剂量、不同时期百草枯中毒肺部MSCT表现具有一定的特点及演变规律。     

容量状态对革兰氏阴性杆菌感染性休克患者血液动力学类型及氧代谢的影响

目的　探讨容量状态对感染性休克患者血液动力学状态及氧化谢的影响。方法　监测10例感染性休克患者不同容量状态下血液动力学及氧化谢的变化。结果　低血容量时,肺动脉嵌压(PAWP)0.8±0.3kPa,心脏指数(CI)2.0±0.4L     

血液灌流治疗急性百草枯中毒笔谈

急性百草枯（PQ）中毒的病死率极高,血液灌流（HP）作为PQ中毒救治的推荐方法,已经在我国得到了广泛应用,但对于HP强度以及是否合并血液透析等治疗方案目前仍无定论。最新的《2013百草枯诊治国内专家共识》推荐的方法,是HP时使用1个或多个灌流器、重复数次。而在临床实践中,临床医师多依据临床经验进行判断,随意性较大。本文就HP治疗PQ中毒的时机、模式、重复次数、以及其他合并治疗作一笔谈,以期对将来临床治疗和临床研究有所帮助。     

百草枯中毒患者的急救护理

目的：探讨百草枯中毒抢救的护理措施,以降低其死亡率。方法：接诊患者后,立即进行洗胃,留置胃管反复洗胃,持续胃肠减压排除毒物,防止毒物继续吸收,减轻对重要脏器及组织的损害;重症患者气管插管与洗胃同时进行,及时进行血液灌流,吸附血液中的毒物,净化血液,做好心理护理和健康教育。结果：47例患者中治愈31例,死亡16例。结论：在百草枯中毒的抢救中,掌握并实施正确的洗胃技术,直接影响抢救成功率。     

Effects of titrated arginine vasopressin on hemodynamic variables and oxygen transport in healthy and endotoxemic sheep

OBJECTIVE: To determine the effects of titrated arginine vasopressin (AVP) alone or in combination with norepinephrine (NE) on hemodynamics and oxygen transport in healthy and endotoxemic sheep. DESIGN: Prospective controlled trial. SETTING: University research laboratory. SUBJECTS: Six adult ewes. INTERVENTIONS: Healthy sheep received AVP as a titrated infusion, initiated with 0.6 units/hr and increased by 0.6 units/hr every 15 mins, either until mean arterial pressure was increased by 20 mm Hg vs. baseline or a maximum of 3.6 units/hr was administered. After 90 mins, AVP infusion was continued with the investigated dosage, and NE (0.2 microg x kg(-1) x min(-1)) was also infused for 90 mins. After a 24-hr period of recovery, endotoxemia was induced and maintained (Salmonella typhosa endotoxin, 10 ng x kg(-1) x min(-1)) in the same sheep for the next 19 hrs. After 16 hrs of endotoxemia, AVP and NE were administered as described previously. MEASUREMENTS AND MAIN RESULTS: Hemodynamics were obtained at baseline, every 15 mins during the titration period, and 60 and 90 mins after additional NE infusion. Variables of oxygen transport were calculated before and after the titration period. In healthy and endotoxemic sheep, AVP reduced heart rate and cardiac index (p <.001) and compromised oxygen delivery (p <.001) and oxygen consumption (healthy sheep, p =.003; endotoxemic sheep, p <.001). Vasopressin infusion did not alter mean pulmonary arterial pressure but increased pulmonary vascular resistance index in both groups (p <.001). Additional infusion of NE further augmented mean arterial pressure and increased cardiac index during endotoxemia (p <.001). This was accompanied by an increase in oxygen delivery and consumption (p <.05 each). CONCLUSIONS: During ovine endotoxemia, AVP decreased cardiac index, compromised oxygen delivery, and increased pulmonary vascular resistance index. These side effects may limit its use as a sole vasopressor during sepsis. Potentially, a simultaneous infusion of AVP and NE could represent a useful therapeutic option.     

中毒严重度评分在急性有机磷中毒救治中的应用研究

目的 采用中毒严重度评分(PSS)方法评价急性有机磷中毒(AOPP)患者的病情严重程度及预后,探讨其临床应用价值.方法 对本研究所属三家医院急诊科2006-10～2008-02收入的116例AOPP患者进行前瞻性研究,入院时进行PSS评分,追踪患者的病情发展及结局,记录住院时间、入院24 h内胆碱酯酶活力、并发症发生情况,按照PSS评分1、2、3分分为三组,比较三组患者住院时间、入院24 h内胆碱_酯酶活力、并发症发生率及预后.结果 PSS评分与住院时间呈正相关(P＜0.001),与24 h内胆碱酯酶活力存在反比关系(P＜0.01).PSS评分越高,并发症发生率越高(P＜0.05),病死率相对增高.结论 入院时PSS评分高低能反映AOPP患者的病情严重程度及预后情况.     

百草枯中毒的治疗及需要重视的若干问题

百草枯（paraquat,PQ）又名克芜踪、对草快,化学名称是1-1-二甲基-4-4-联吡啶阳离子盐,主要成分是1,1＇二甲基4,4＇二氯二吡啶,分子式为C12H14Cl2N2,是目前在世界范围内广泛使用的有机杂环类接触性脱叶剂及除草剂,易溶于水,微溶于酒精,在酸性及中性环境中稳定,遇碱易分解。     

急性百草枯中毒的临床分型与预后分析

目的 探讨急性百草枯中毒的临床分型及与预后的关系,以期建立一种快速简便的分型方法,加深对百草枯中毒的认知.方法 对南京军区南京总医院急救医学科2005年1月至2009年9月收治的43例百草枯急性中毒患者的资料进行回顾分析后,以受累脏器及损害程度作为分型标准,在就诊24 h内进行临床分型,通过Fisher精确概率法探讨各分型与预后的关系.结果 43例百草枯急性中毒患者中有轻度中毒6例,无死亡病例,中度中毒20例,死亡9例(死亡率45.0%),重度中毒17例,死亡16例(死亡率94.1%);各型的死亡率不全相等(P＜0.01);轻度与中度死亡率差异无统计学意义(P=0.063),轻度与重度死亡率差异有统计学意义(P＜0.01),中度与重度死亡率差异有统计学意义(P=0.002).结论 急性百草枯中毒的机制及临床特征很复杂,本临床分型方法能较好的区分各型疾病.