CORRELATION OF PERADENIYA ORGANOPHOSPHORUS POISONING SCALE (POP) AND OUTCOME OF ORGANOPHOSPHORUS POISONING

Original Research Ar cle Regmi G et al © Authors retain copyright and grant the journal right of first publica on with the work simultaneously licensed under Crea ve Commons A ribu on License CC BY 4.0 that allows others to share the work with an acknowledgment of the work's authorship and ini al publica on in this journal. * Corresponding Author


Introduc on
Organophosphorus poisoning is one of the common causes for the intensive care admission in the developing countries. This study was conducted to assess the correla on between Peradeniya Organophosphorus Poisoning (POP) scale and the outcomes in poisoningin a ter ary care hospital in Eastern Nepal.

Objec ve
To assess the severity and outcome of OP compound poisoning with the correla on of POP score.

Methodology
This was a prospec ve observa onal study conducted over 6 months in the intensive care unit at ter ary care hospital in the eastern part of Nepal. The study included all OP poisoning pa ents presen ng in the emergency department and finally admi ed to intensive care unit who fulfilled the inclusion criteria. Correla on was made between POP scores and outcomes in terms of intensive care unit (ICU) stay, need of ven la on and mortality was assessed.

Result
Fi y pa ents with OP poisoning were included in the study. Suicide a empt was the most common reason for poisoning. The incidence of poisoning was more common among males(72%) and significant majority were aged younger than 35 years (84%). On admission, the number of pa ents in mild, moderate and severe poisoning group were 52%, 30% and 18% respec vely. Rates for ICU stay, respiratory failure requiring ven lator and mortality was significantly (p<0.001) higher in severe POP scale.

Conclusion
The POP scale is a useful clinical assessment tool to assess and categorize pa ents with OP poisoning according to severity and in predic ng their clinical outcomes. Organophosphorus compound poisoning is a major clinical and public problem across rural Asia. Pes cide poisoning accounts for about 60 % of the total es mated 500 000 deaths from self-harm each year. Suicidal a empt is seen as with a major cause of organophosphate (OP) toxicity in Nepal. Nepal mainly is an agricultural country. The pes cides and insec cides containing organ ophosphorus compounds are easily available over the counter. This leads to the misuse of the pes cides and insec cides as poisoning substances. The mortality rate is 7.4% for appropriately treated OP poisoning in Nepal, while 10% worldwide, and 8 0.18% in the US.

KEYWORD
Organophosphate (OP) inhibits the esterase enzyme, acetyl cholin esterase,which increase sacetylcholine in muscarinic and nico nic receptors in the central and peripheralnervous systems. Pa ents experience bradycardia, miosis, lacrima on, saliva on, bronchorrhea, and bronchospasm within minutes to hours of exposure or inges on, which are the signs and symptoms of cholinergic excess: 40% of pa ents may develop fascicula ons and bulbar, proximal, and respiratory muscle weakness a er 1-4 days of exposure, which are nico nic symptomsdepending upon the stage of 8 organophosphorus poisoning.
Though serum cholinesterase level has been used very commonly to assess the severity of the organophosphorus poisoning, this test is not easily available and thus make it unsuitable for its uses in clinical prac ce. Peradeniya Organophosphorus poisoning(POP) scale is a simple tool that has been developed to assess the severity of the poisoning based on the symptoms at the me of presenta on. This tool was developed to assess the severity of OP intoxica on in Department of Medicine, Faculty of Medicine, University of Peradeniya, Sri Lanka in 1993 which includes five most common signs and symptoms of OP poison like respiratory rate, pulse rate, pupil size, level of consciousness, seizure ac vity and fascicula on. Parameters were scored from zero to two at ini al presenta on. The grading of severity was as mild (score 0-3), moderate (score 11 4-7) and severe (score 8-11).
As POP scale uses simple clinical parameters of organophosphorus poisoning, this scoring system can easily be used in emergency and ICU by the health care providers. The POP scale has become useful in es ma ng the outcome on the basis with the severity of the poisoning in developing 6 countries like Nepal. Rajbanshi LK et al has observed that the leading cause of acute poisoning requiring admission to the ICU in the eastern part of Nepal is Organophosphorus poisoning. According to them 43.5% of the total poisoning are due to organophosphorus compounds in the eastern 6 Nepal. Since organophosphorus compound poisoning is a medical emergency, it is important to know its nature, clinical presenta on, severity and outcome in order to ini ate appropriate measures including proper planning, treatment and preven on. As men oned earlier cholinesterase test is not easily available in all the centers in eastern Nepal POP scoring system can be an alterna ve easy approach for assessing the severity of poisoning in this part of Nepal. Thus, this present study was under taken to assess the severity and outcome of OP compound poisoning with the help of POP score in the eastern part of Nepal and to find out the correla on between POP scale and severity of organophosphorus poisoning.

METHODOLOGY
This was the prospec ve cross-sec onal study conducted in the intensive care unit of the ter ary care hospital in the eastern part of Nepal. We chose convenience sampling method to include study par cipants. The total dura on of this study was 6 months star ng from February 15, 2019, to August 15, 2019. A er ethical approval was obtained from the ins tu onal ethical board with reference number: NMCTH :248/2019and informed consent for the par cipa on in the study was taken from the next of kin of the pa ent. All the pa ent who had the history of organophosphorus compound poisoning with in twenty-four hours of admission and presented with characteris c clinical signs and symptoms of organophosphorus poisoning were included in the study. The specific clinical feature of Organophosphorus poisoning expected to present at the me of poisoning were pupillary changes, excessive saliva on, bradycardia, altered sensorium or agita on, fascicula on and seizure.
Poisoning of more than twenty-four hours before admission, p o i s o n i n g w i t h o t h e r c o m p o u n d s a l o n g w i t h organophosphates, pa ent with the comorbid condi ons and pregnant women were not included in the study. The POP scoring system was used to assess the pa ent severity based on the clinical features presented in the emergency department. The pa ents were admi ed to the intensive care unit a er ini al resuscita on and atropiniza on and were managed asper the guideline of management of OP poisoning. The age and sex of the pa ents, the severity of the poisoning on the basis of POP scoring system and outcome of the pa ents in terms of dura on of ICU stay, hospital stay, need for respiratory support and mortality were studied. Mortality was observed as a number of deaths within the hospital stay.
The data obtained were coded and entered into Microso Excel Worksheet. Data were analyzed using Sta s cal Package for the Social Sciences Version 23.0. The categorical data were expressed as rates, ra os, and propor ons; the comparison was done using either Chi-squaretest or Fisher's exact test. The con nuous data were expressed as mean ± standard devia on, and comparison was done using with an independent sampl et-test. P ≤ 0.05 was considered assta s cally significant.

RESULT
In the 6 months dura on total of 160 pa ents who were admi ed in the ICU due to poisoning, out of them 89 admission was due to organophosphorus compound poisoning. In this study 50 pa ents were included and the remaining 39 pa ents of organophosphorus poisoning were excluded from the study due to various reason as men oned in Figure 1.  The Figure 2 shows that 26 (52%) pa ents were between the age group of 16-25, 16(32%) pa ents between the age group of 26-35 and remaining 8 (16%) pa ents were above 35 years age.

Figure 2: Peradeniya Scale with age group
In the present study, organophosphorus poisoning was seen in 72% of the male par cipants while it was 28% in female par cipants.
The rela onship of Peradeniya scale scoring and development of respiratory failure requiring ven latory support was shown in table 2. It was observed that 88.9% of the par cipants with severe Perandeniya scoring developed respiratory failure and required ven latory support while only 11.5% and 33.3% of the par cipants with mild and moderate Perandeniya scoring respec vely required ven latory support. The dura on of ICU stay was classified as less than 7 days or more than 7 days as per suggested by Chaudhary R et al. 11 It was observed that 88.9 % of the par cipant with severe Peradeniya scale has ICU stay more than 7 days while majority of the par cipants with mild to moderate Peradeniya scale had a ICU stay less than 7 days.

DISCUSSION
The organophosphorus compounds are easily available as an insec cide and pes cide for agricultural purpose but unfortunately, they are misused leading to the acute poisoning. It is essen al that these poisoning cases should be promptly evaluated, assessed the severity and should be managed promptly for be er outcome.
The present study showed the higher incidence of poisoning in male(72%) compared to female(28%) similar to the other [13][14][15] studies observed by Selvaraj1 Tet al and Subhash et al.
The present study showed that majority of the pa ent with the severe Peradeniya scale developed respiratory failure and required ven latory support. The sepa ents had severe clinical presenta on with low sensorium, excessive saliva on and hemodynamically unstable. This might be the possible reason requiring ven latory support. The study conducted by Shashank Tripathi observed that none of the pa ent with mild symptoms needed ven lator support while five pa ents with moderate symptoms and seven pa ents with 16 severe symptoms required ven lator support.
Shah Harsh D et al, in a similar study suggested that ven lator requirement was higher in cases with severe POP score.In a similar study conducted by Goel A et, predicted a higher incidence (34.95%) required assisted ven la on. The study showed 36 out of 103 pa ents required the ven lator 18 support.
Similarly, the pa ent with severe Peradeniya scale had longer ICU stay. As men oned earlier the pa ent with severe Peradeniya scale required respiratory support and were more prone to develop other organ failure. This, facts might has contributed the longer dura on of ICU stay.
Similar data were extracted in the study conducted by 11 Pradeep v et al, with 3 pa ents in mild group, 9 pa ents in moderate group and 3 pa ents in severe group stayed in ICU for more than 7 days .

CONCLUSION
In eastern part of Nepal, male showed higher incidence of OP poisoning with higher incidence of respiratory support, longer dura on of ICU stay and increased mortality with higher POP score. The mortality, dura on of ICU stay and subject requiring ven la on can be predicted early by applying the POP score at the me of admission. Thus, POP scoring system can be beneficial to assess the severity of poisoning in resource limited setup.

LIMITATION OF STUDY
The present study had some limita ons. The study was carried out in a single center. Difficul es might arise in categoriza on of pa ents in severe poisoning as according to POP scoring, pa ents with rela vely severe OP poisoning, have rela vely higher respiratory rate but severe OP poisoning may cause either central respiratory depression decreasing respiratory rate or may cause tachypnoea in the context of bronchorrhea, bronchoconstric on or respiratory muscle weakness. The study may not represent the total popula on of the country as only 50 cases were enrolled in the study.

ACKNOWLEDGEMENT
Author would like to thank all the par cipants in the study for their sincere and ac ve par cipa on.

CONFLICTS OF INTEREST
There are no conflicts of interest

FINANCIAL DISCLOSURE
None.