Journal of Toxicology

CLINICAL TOXICOLOGY

Vol 42 No 4 pp 343ndash347 2004

Survival Pattern in Patients with Acute OrganophosphatePoisoning Receiving Intensive Care

U A D D Munidasa MBBS12 I B Gawarammana MBBS13

S A M Kularatne MD MRCP13

P V R Kumarasiri MSc MD14

and C D A Goonasekera MD MRCP PhD12

1Intensive Care Unit Teaching Hospital Peradeniya Sri Lanka2Department of Anesthesiology 3Department of Medicine and

4Department of Community Medicine Faculty of Medicine

University of Peradeniya Peradeniya Sri Lanka

ABSTRACT

Background Approximately 35 of patients acutely poisoned with organophosphates

(OP) in developing countries like Sri Lanka require intensive care and mechanical

ventilation However death rates remain high Objective To study the outcomes and

predictors of mortality in patients with acute OP poisoning requiring intensive therapy

at a regional center in Sri Lanka over a period of 40 months Methods Retrospective

analysis of all intensive care records of patients with acute OP poisoning admitted to

the Intensive Care Unit (ICU) between March 1998 and July 2001 Results During the

study period 126 subjects were admitted to the ICU with acute OP poisoning Records

of 10 patients were lost and those of 37 were incomplete and hence were excluded All

the remaining 71 patients (59 male) had required endotracheal intubation and

mechanical ventilation for a period of four (median) days (range 1ndash27) in addition to

gastric lavage and standard therapy with atropine and oximes and adequate hydration

Of these 71 patients 36 (28 male) had died Life table analysis demonstrated a steep

decline in the cumulative survival to 67 during the first three days Systolic blood

pressure of lt100 mmHg and FiO2 of gt40 to maintain a SpO2 of gt92 within the

first 24 h were recognized as poor prognostic indicators among mechanically

ventilated patients Conclusion Mortality following OP poisoning remains high

despite adequate respiratory support intensive care and specific therapy with

Correspondence C D A Goonasekera Senior lecturer MD MRCP PhD Department of Anesthesiology Faculty of

Medicine University of Peradeniya Peradeniya Sri Lanka E-mail cgoonasesltlk

343

DOI 101081CLT-120039539 0731-3810 (Print) 1097-9875 (Online)

Copyright D 2004 by Marcel Dekker Inc wwwdekkercom

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atropine and oximes One-third of the subjects needing mechanical ventilation and

reaching intensive care units die within the first 72 h of poisoning Systolic blood

pressure of less than 100 mmHg and the necessity of a FiO2 gt40 to maintain

adequate oxygenation are predictors of poor outcome in patients mechanically

ventilated in the ICU

Key Words Organophosphate poisoning Mortality Cardiac effects Poor prognostic

indicators

INTRODUCTION

Organophosphates account for 50 of all cases

of acute poisonings and 80 of pesticide poisonings

admitted to hospitals in Sri Lanka (1ndash3) Approxi-

mately 35 of patients with acute OP poisoning re-

quire assisted ventilation (4) Therefore it can be

assumed that one-third of all OP poisoning cases

need intensive care for the purpose of assisted ven-

tilation Studies of mortality among ventilated

patients are scanty in the literature and it is es-

timated to be between 16 and 50 in South Africa

and Sri Lanka respectively (56) At present one-

tenth of admissions to the intensive care units (ICUs)

in Sri Lanka constitute subjects with acute OP poisoning

requiring active treatment particularly ventilator sup-

port (7)

OBJECTIVE

The study was intended to analyze the pattern of

survival and identify the risk factors that may predict

poor outcome in patients requiring ventilatory

support and intensive care following acute organo-

phosphate poisoning

SUBJECTS AND METHODS

This retrospective study included the compre-

hensive medical nursing and intensive care mon-

itoring records of all subjects admitted with acute

organophosphorous poisoning to the Intensive Care

Unit (ICU) of the Teaching Hospital Peradeniya

over a period of 40 months starting from

March 1998

The qualifying case records were identified from

the ICU admission register and traced from the

medical record archives of the hospital We collected

patient information regarding poisoning clinical

features the treatments given parameters monitored

and the outcomes using a data entry form developed

specifically for this study Establishment of the

diagnosis in all cases at inception was based on the

cholinergic clinical features OP smell in gastric

contents history and other circumstantial evidence

such as availability of a poison bottle or a label

found in the vicinity and brought to the hospital by

the relatives The data were analyzed using SPSS

100 statistical software and Epinfo 2001 A life table

was plotted The risk factors predicting mortality

were discerned using odds ratios

RESULTS

During the study period 126 subjects were

admitted to the ICU with acute OP poisoning All

had ingested the poison 112 (97) on suicidal intent

and 4 (3) accidentally Although a specific organo-

phosphorous agent has been identified on circumstantial

Figure 1 The survival function among patients needing

intensive care therapy and mechanical ventilation following

acute organophosphate poisoning

344 Munidasa et al

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evidence in 29 (ie a bottle containing the poison was

found on site there were eyewitnesses etc) all cases

were diagnosed on clinical evidence (such as smell

clinical features such as pin point pupils sweating

respiratory difficulty with increased bronchial secre-

tions) as there was no ready analytical diagnostic test

available for use on their biological material All

patients were given atropine and pralidoxime based on

a standard protocol (8)

Records of 10 patients were lost and those of 37

were incomplete and hence were excluded All the

remaining 71 patients (59 male) had required endotra-

cheal intubation and mechanical ventilation for a

period of 4 (median) days (range 1ndash27) in addition

to gastric lavage standard therapy and adequate

hydration Of these 71 patients 36 (28 male) had

died A Kaplan Meier survival curve in this group

showed a cumulative survival of 067 at 3 days and

033 at 16 days from the hour of poisoning and no

mortality subsequently (Fig 1)

Of the 71 mechanically ventilated patients 64 had

recorded clinical information on all parameters that

were used in the analysis to gauge predictors of poor

outcome Twenty-one (33) of the 64 had on average

a systolic blood pressure of less than 100 mmHg despite

adequate hydration with saline and inotropes (Dobut-

amine and Dopamine doses exceeding 10 mgkgmin)

during the first 24 h and 18 of them died In contrast 32 of

the 35 survivors had on average a SBP of gt100 mmHg

during the first 24 h (Table 1)

Systolic blood pressure of less than 100 mmHg

during the first 24 h since admission to the ICU was a

significant predictor of poor outcome Odds ratio was

1745 (95 CI 43ndash7086)

The peripheral SpO2 of those who died and those

who survived were mean (SE) 940 (08) and mean

(SE) 957 (14) respectively and were not signifi-

cantly different However those who died needed a

significantly higher fraction of inspired oxygen (FiO2)

during the first 24 h of poisoning to maintain a

satisfactory peripheral SpO2 ie gt92 The patients

who needed a FiO2 higher than 40 had a higher

risk of death (Table 2) odds ratio was 90 (95 CI

184ndash4403)

DISCUSSION

The estimates of overall mortality following OP

ingestion ranges from 20 to 25 (239ndash11) These

reports consider the delay in discovery and transport

insufficient respiratory management aspiration pneu-

monia and sepsis as attributes to the cause of death in

the most cases

The mortality in mechanically ventilated patients

ranges from 13 to 50 (5612) The recognized

predictors of poor outcome include prolonged QT

interval on the ECG (13) APACHE II score of 26 or

more (14) low-frequency components of blood pres-

sure and heart rate signals on Spectral analysis (12) and

attempted suicide low PaO2 stupor and abnormal

chest X-ray on admission (5) The mortality rate

among the mechanically ventilated patients in our

study was 50 (35 of 71 died) and is similar to other

available data from Sri Lanka (6) In India 35 of the

patients with OP poisoning require assisted ventilation

(4) Assuming that all patients who reached a hospital

before death were intubated and mechanically venti-

lated we can extrapolate that the mortality rate on OP

poisoning with intensive care support facility would

range from 15ndash20 ie one in five patients will die

despite the availability of intensive care in the

developing countries All the patients in our study

had adequate peripheral oxygen saturation maintained

and hence none of the deaths were a direct conse-

quence of intermediate syndrome [ie the respiratory

muscle weakness observed within 6 to 10 days of OP

poisoning (8)] as they were in an ICU and were

mechanically ventilated The survival graph indicates

that by the end of the third day only 67 survived

Death was common in the subjects with hypotension

during the first 24 h and subjects who needed high-

inspired oxygen concentrations to maintain satisfactory

peripheral oxygen saturation

The current study recognizes that measured

systolic blood pressure less than 100 mmHg and the

need for FiO2gt40 to maintain adequate peripheral

Table 1 Average systolic blood pressure of ventilated

patients during the first 24 h

Number of

deaths

Number of

survivors

SBPlt100 mmHg 18 3

SBPgt100 mmHg 11 32

Table 2 The FiO2 of mechanically ventilated patients

Number of deaths Number of survivors

FiO2 gt40 27 21

FiO2 lt40 2 14

Survival Pattern in Patients with Acute OP Poisoning 345

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oxygen saturation within the first 24 h since poisoning

are predictors of poor outcome in patients mechanically

ventilated in the ICU Although the odds ratios reach a

statistically significant level the wider confidence

internal particularly seen with low blood pressure as

a risk factor suggests that other factors may also be

contributing significantly to mortality For instance the

type of compound ingested the dose retained duration

since poisoning before being brought to intensive care

duration of hypoxia before therapy and the proportion

of poison removed by gastric lavage are other

immeasurable factors that may be making a contribu-

tion in this context The overall mortality is still high

despite institution of prompt ventilatory support in

addition to gastric lavage at inception and standard

therapy with atropine and pralidoxime Higher mortal-

ity rates in ventilated patients warrant research into

other factors which may influence the final outcome

Our observation of low systolic blood pressure and

requirement of FiO2gt40 suggests global impairment

of myocardial function despite adequate hydration

which can lead to reduction of pulmonary and systemic

circulation The most likely reason for myocardial

depression is the direct effect of OP with structural

damage Povoa et al reported focal myocardial

necrosis in a patient who died following ingestion of

OP who also had prolonged QTc (15) However

parasympathetic overactivity hypoxia acidosis and

electrolyte derangement may also depress the myocar-

dium in patients with OP poisoning Chuang et al in

their series of 223 patients reported that 435 had

prolonged QTc interval on the electrocardiography

(ECG) at presentation and these patients had a

significantly higher mortality and a higher rate of

respiratory failure (13) compared with the patients who

did not display QTc prolongation

CONCLUSION

Deaths due to OP poisoning remain high during

the first 72 h despite optimal respiratory care with

mechanical ventilation and oxygen supplementation

A low systolic blood pressure and a requirement of

FiO2gt40 within the first 24 h of OP poisoning are

predictors of mortality Therefore patients with systolic

blood pressure lt100 mmHg and those who need

FiO2gt40 to maintain their SpO2 above 92 should

be considered as at high risk of death and hence treated

in an intensive care environment Cardiovascular

effects of OP seem to be the major contributor for

mortality when temporary respiratory failure of OP

poisoning is controlled by mechanical ventilation

ACKNOWLEDGMENTS

The authors appreciate the help and support

provided by all medical staff and nursing staff of

Peradeniya Teaching Hospital in the clinical manage-

ment of these patients

REFERENCES

1 Goonasekera CDA Wimalaratne H Karalliedde

LD Changing profile of poisoning in a District

Hospital in Sri Lanka Sri Lanka J Med 1999835ndash38

2 Karalliedde L Senanayake N Pattern of acute

poisoning in a medical unit in central Sri Lanka

Forensic Sci Int 1988 36101ndash1043 Jeyaratnam J de Alwis Seneviratne RS

Copplestone JF Survey of pesticide poisoning

in Sri Lanka Bull WHO 1982 60615ndash6194 Goel A Joseph S Dutta TK Organophosphate

poisoning predicting the need for ventilatory

support J Assoc Phys Ind 1998 46786ndash7905 Bardin PG van Eeden SF Joubert JR Intensive

care management of acute organophosphate poi-

soning a 7-year experience in the western Cape S

Afr Med J 1987 72593ndash5976 Rajapakse VP Wijesekera S Outcome of mechan-

ical ventilation in Sri Lanka Ann R Coll Surg Engl

1989 71344ndash3467 Vasanthathilaka VWJK Goonasekera CDA An

audit of admissions to an intensive care unit in a

regional centre in Sri Lanka Ceylon Med J 199742145ndash148

8 Karalliedde L Senanayake N Organophosphorus

insecticide poisoning Br J Anaesth 1989 63736ndash750

9 Wyckoff DW Davies JE Barquet A Davis JH

Diagnostic and therapeutic problems of parathion

poisonings Ann Intern Med 1968 68875ndash88210 Yamashita M Tanaka J Ando Y Human mortality

in organophosphate poisonings Vet Hum Toxicol

1997 3984ndash8511 Abdollahi M Jalali N Sabzevari O Hoseini R

Ghanea T A retrospective study of poisoning in

Tehran J Toxicol Clin Toxicol 1997 35387ndash39312 Yen DH Yien HW Wang LM Lee CH Chan SH

Spectral analysis of systemic arterial pressure and

346 Munidasa et al

Clin

ical

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icol

ogy

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ded

from

info

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14

For

pers

onal

use

onl

y

heart rate signals of patients with acute respiratory

failure induced by severe organophosphate poi-

soning Crit Care Med 2000 282805ndash281113 Chuang FR Jang SW Lin JL Chern MS Chen JB

Hsu KT QTc prolongation indicates a poor

prognosis in patients with organophophate poison-

ing Am J Emerg Med 1996 14451ndash453

14 Lee P Tai DY Clinical features of patients with

acute organophosphate poisoning requiring inten-

sive care Intensive Care Med 2001 27694ndash69915 Povoa R Cardoso SH Luna Filho B Ferreira

Filho C Ferreira M Ferreira C Organophosphate

poisoning and myocardial necrosis Arq Bras

Cardiol 1997 68377ndash380

Submitted October 28 2003Accepted January 29 2004

Survival Pattern in Patients with Acute OP Poisoning 347

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evidence in 29 (ie a bottle containing the poison was

found on site there were eyewitnesses etc) all cases

were diagnosed on clinical evidence (such as smell

clinical features such as pin point pupils sweating

respiratory difficulty with increased bronchial secre-

tions) as there was no ready analytical diagnostic test

available for use on their biological material All

patients were given atropine and pralidoxime based on

a standard protocol (8)

Records of 10 patients were lost and those of 37

were incomplete and hence were excluded All the

remaining 71 patients (59 male) had required endotra-

cheal intubation and mechanical ventilation for a

period of 4 (median) days (range 1ndash27) in addition

to gastric lavage standard therapy and adequate

hydration Of these 71 patients 36 (28 male) had

died A Kaplan Meier survival curve in this group

showed a cumulative survival of 067 at 3 days and

033 at 16 days from the hour of poisoning and no

mortality subsequently (Fig 1)

Of the 71 mechanically ventilated patients 64 had

recorded clinical information on all parameters that

were used in the analysis to gauge predictors of poor

outcome Twenty-one (33) of the 64 had on average

a systolic blood pressure of less than 100 mmHg despite

adequate hydration with saline and inotropes (Dobut-

amine and Dopamine doses exceeding 10 mgkgmin)

during the first 24 h and 18 of them died In contrast 32 of

the 35 survivors had on average a SBP of gt100 mmHg

during the first 24 h (Table 1)

Systolic blood pressure of less than 100 mmHg

during the first 24 h since admission to the ICU was a

significant predictor of poor outcome Odds ratio was

1745 (95 CI 43ndash7086)

The peripheral SpO2 of those who died and those

who survived were mean (SE) 940 (08) and mean

(SE) 957 (14) respectively and were not signifi-

cantly different However those who died needed a

significantly higher fraction of inspired oxygen (FiO2)

during the first 24 h of poisoning to maintain a

satisfactory peripheral SpO2 ie gt92 The patients

who needed a FiO2 higher than 40 had a higher

risk of death (Table 2) odds ratio was 90 (95 CI

184ndash4403)

DISCUSSION

The estimates of overall mortality following OP

ingestion ranges from 20 to 25 (239ndash11) These

reports consider the delay in discovery and transport

insufficient respiratory management aspiration pneu-

monia and sepsis as attributes to the cause of death in

the most cases

The mortality in mechanically ventilated patients

ranges from 13 to 50 (5612) The recognized

predictors of poor outcome include prolonged QT

interval on the ECG (13) APACHE II score of 26 or

more (14) low-frequency components of blood pres-

sure and heart rate signals on Spectral analysis (12) and

attempted suicide low PaO2 stupor and abnormal

chest X-ray on admission (5) The mortality rate

among the mechanically ventilated patients in our

study was 50 (35 of 71 died) and is similar to other

available data from Sri Lanka (6) In India 35 of the

patients with OP poisoning require assisted ventilation

(4) Assuming that all patients who reached a hospital

before death were intubated and mechanically venti-

lated we can extrapolate that the mortality rate on OP

poisoning with intensive care support facility would

range from 15ndash20 ie one in five patients will die

despite the availability of intensive care in the

developing countries All the patients in our study

had adequate peripheral oxygen saturation maintained

and hence none of the deaths were a direct conse-

quence of intermediate syndrome [ie the respiratory

muscle weakness observed within 6 to 10 days of OP

poisoning (8)] as they were in an ICU and were

mechanically ventilated The survival graph indicates

that by the end of the third day only 67 survived

Death was common in the subjects with hypotension

during the first 24 h and subjects who needed high-

inspired oxygen concentrations to maintain satisfactory

peripheral oxygen saturation

The current study recognizes that measured

systolic blood pressure less than 100 mmHg and the

need for FiO2gt40 to maintain adequate peripheral

Table 1 Average systolic blood pressure of ventilated

patients during the first 24 h

Number of

deaths

Number of

survivors

SBPlt100 mmHg 18 3

SBPgt100 mmHg 11 32

Table 2 The FiO2 of mechanically ventilated patients

Number of deaths Number of survivors

FiO2 gt40 27 21

FiO2 lt40 2 14

Survival Pattern in Patients with Acute OP Poisoning 345

Clin

ical

Tox

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from

info

rmah

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care

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by

Uni

vers

ity o

f W

ater

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on 1

028

14

For

pers

onal

use

onl

y

oxygen saturation within the first 24 h since poisoning

are predictors of poor outcome in patients mechanically

ventilated in the ICU Although the odds ratios reach a

statistically significant level the wider confidence

internal particularly seen with low blood pressure as

a risk factor suggests that other factors may also be

contributing significantly to mortality For instance the

type of compound ingested the dose retained duration

since poisoning before being brought to intensive care

duration of hypoxia before therapy and the proportion

of poison removed by gastric lavage are other

immeasurable factors that may be making a contribu-

tion in this context The overall mortality is still high

despite institution of prompt ventilatory support in

addition to gastric lavage at inception and standard

therapy with atropine and pralidoxime Higher mortal-

ity rates in ventilated patients warrant research into

other factors which may influence the final outcome

Our observation of low systolic blood pressure and

requirement of FiO2gt40 suggests global impairment

of myocardial function despite adequate hydration

which can lead to reduction of pulmonary and systemic

circulation The most likely reason for myocardial

depression is the direct effect of OP with structural

damage Povoa et al reported focal myocardial

necrosis in a patient who died following ingestion of

OP who also had prolonged QTc (15) However

parasympathetic overactivity hypoxia acidosis and

electrolyte derangement may also depress the myocar-

dium in patients with OP poisoning Chuang et al in

their series of 223 patients reported that 435 had

prolonged QTc interval on the electrocardiography

(ECG) at presentation and these patients had a

significantly higher mortality and a higher rate of

respiratory failure (13) compared with the patients who

did not display QTc prolongation

CONCLUSION

Deaths due to OP poisoning remain high during

the first 72 h despite optimal respiratory care with

mechanical ventilation and oxygen supplementation

A low systolic blood pressure and a requirement of

FiO2gt40 within the first 24 h of OP poisoning are

predictors of mortality Therefore patients with systolic

blood pressure lt100 mmHg and those who need

FiO2gt40 to maintain their SpO2 above 92 should

be considered as at high risk of death and hence treated

in an intensive care environment Cardiovascular

effects of OP seem to be the major contributor for

mortality when temporary respiratory failure of OP

poisoning is controlled by mechanical ventilation

ACKNOWLEDGMENTS

The authors appreciate the help and support

provided by all medical staff and nursing staff of

Peradeniya Teaching Hospital in the clinical manage-

ment of these patients

REFERENCES

1 Goonasekera CDA Wimalaratne H Karalliedde

LD Changing profile of poisoning in a District

Hospital in Sri Lanka Sri Lanka J Med 1999835ndash38

2 Karalliedde L Senanayake N Pattern of acute

poisoning in a medical unit in central Sri Lanka

Forensic Sci Int 1988 36101ndash1043 Jeyaratnam J de Alwis Seneviratne RS

Copplestone JF Survey of pesticide poisoning

in Sri Lanka Bull WHO 1982 60615ndash6194 Goel A Joseph S Dutta TK Organophosphate

poisoning predicting the need for ventilatory

support J Assoc Phys Ind 1998 46786ndash7905 Bardin PG van Eeden SF Joubert JR Intensive

care management of acute organophosphate poi-

soning a 7-year experience in the western Cape S

Afr Med J 1987 72593ndash5976 Rajapakse VP Wijesekera S Outcome of mechan-

ical ventilation in Sri Lanka Ann R Coll Surg Engl

1989 71344ndash3467 Vasanthathilaka VWJK Goonasekera CDA An

audit of admissions to an intensive care unit in a

regional centre in Sri Lanka Ceylon Med J 199742145ndash148

8 Karalliedde L Senanayake N Organophosphorus

insecticide poisoning Br J Anaesth 1989 63736ndash750

9 Wyckoff DW Davies JE Barquet A Davis JH

Diagnostic and therapeutic problems of parathion

poisonings Ann Intern Med 1968 68875ndash88210 Yamashita M Tanaka J Ando Y Human mortality

in organophosphate poisonings Vet Hum Toxicol

1997 3984ndash8511 Abdollahi M Jalali N Sabzevari O Hoseini R

Ghanea T A retrospective study of poisoning in

Tehran J Toxicol Clin Toxicol 1997 35387ndash39312 Yen DH Yien HW Wang LM Lee CH Chan SH

Spectral analysis of systemic arterial pressure and

346 Munidasa et al

Clin

ical

Tox

icol

ogy

Dow

nloa

ded

from

info

rmah

ealth

care

com

by

Uni

vers

ity o

f W

ater

loo

on 1

028

14

For

pers

onal

use

onl

y

heart rate signals of patients with acute respiratory

failure induced by severe organophosphate poi-

soning Crit Care Med 2000 282805ndash281113 Chuang FR Jang SW Lin JL Chern MS Chen JB

Hsu KT QTc prolongation indicates a poor

prognosis in patients with organophophate poison-

ing Am J Emerg Med 1996 14451ndash453

14 Lee P Tai DY Clinical features of patients with

acute organophosphate poisoning requiring inten-

sive care Intensive Care Med 2001 27694ndash69915 Povoa R Cardoso SH Luna Filho B Ferreira

Filho C Ferreira M Ferreira C Organophosphate

poisoning and myocardial necrosis Arq Bras

Cardiol 1997 68377ndash380

Submitted October 28 2003Accepted January 29 2004

Survival Pattern in Patients with Acute OP Poisoning 347

Clin

ical

Tox

icol

ogy

Dow

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ded

from

info

rmah

ealth

care

com

by

Uni

vers

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f W

ater

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on 1

028

14

For

pers

onal

use

onl

y

oxygen saturation within the first 24 h since poisoning

are predictors of poor outcome in patients mechanically

ventilated in the ICU Although the odds ratios reach a

statistically significant level the wider confidence

internal particularly seen with low blood pressure as

a risk factor suggests that other factors may also be

contributing significantly to mortality For instance the

type of compound ingested the dose retained duration

since poisoning before being brought to intensive care

duration of hypoxia before therapy and the proportion

of poison removed by gastric lavage are other

immeasurable factors that may be making a contribu-

tion in this context The overall mortality is still high

despite institution of prompt ventilatory support in

addition to gastric lavage at inception and standard

therapy with atropine and pralidoxime Higher mortal-

ity rates in ventilated patients warrant research into

other factors which may influence the final outcome

Our observation of low systolic blood pressure and

requirement of FiO2gt40 suggests global impairment

of myocardial function despite adequate hydration

which can lead to reduction of pulmonary and systemic

circulation The most likely reason for myocardial

depression is the direct effect of OP with structural

damage Povoa et al reported focal myocardial

necrosis in a patient who died following ingestion of

OP who also had prolonged QTc (15) However

parasympathetic overactivity hypoxia acidosis and

electrolyte derangement may also depress the myocar-

dium in patients with OP poisoning Chuang et al in

their series of 223 patients reported that 435 had

prolonged QTc interval on the electrocardiography

(ECG) at presentation and these patients had a

significantly higher mortality and a higher rate of

respiratory failure (13) compared with the patients who

did not display QTc prolongation

CONCLUSION

Deaths due to OP poisoning remain high during

the first 72 h despite optimal respiratory care with

mechanical ventilation and oxygen supplementation

A low systolic blood pressure and a requirement of

FiO2gt40 within the first 24 h of OP poisoning are

predictors of mortality Therefore patients with systolic

blood pressure lt100 mmHg and those who need

FiO2gt40 to maintain their SpO2 above 92 should

be considered as at high risk of death and hence treated

in an intensive care environment Cardiovascular

effects of OP seem to be the major contributor for

mortality when temporary respiratory failure of OP

poisoning is controlled by mechanical ventilation

ACKNOWLEDGMENTS

The authors appreciate the help and support

provided by all medical staff and nursing staff of

Peradeniya Teaching Hospital in the clinical manage-

ment of these patients

REFERENCES

1 Goonasekera CDA Wimalaratne H Karalliedde

LD Changing profile of poisoning in a District

Hospital in Sri Lanka Sri Lanka J Med 1999835ndash38

2 Karalliedde L Senanayake N Pattern of acute

poisoning in a medical unit in central Sri Lanka

Forensic Sci Int 1988 36101ndash1043 Jeyaratnam J de Alwis Seneviratne RS

Copplestone JF Survey of pesticide poisoning

in Sri Lanka Bull WHO 1982 60615ndash6194 Goel A Joseph S Dutta TK Organophosphate

poisoning predicting the need for ventilatory

support J Assoc Phys Ind 1998 46786ndash7905 Bardin PG van Eeden SF Joubert JR Intensive

care management of acute organophosphate poi-

soning a 7-year experience in the western Cape S

Afr Med J 1987 72593ndash5976 Rajapakse VP Wijesekera S Outcome of mechan-

ical ventilation in Sri Lanka Ann R Coll Surg Engl

1989 71344ndash3467 Vasanthathilaka VWJK Goonasekera CDA An

audit of admissions to an intensive care unit in a

regional centre in Sri Lanka Ceylon Med J 199742145ndash148

8 Karalliedde L Senanayake N Organophosphorus

insecticide poisoning Br J Anaesth 1989 63736ndash750

9 Wyckoff DW Davies JE Barquet A Davis JH

Diagnostic and therapeutic problems of parathion

poisonings Ann Intern Med 1968 68875ndash88210 Yamashita M Tanaka J Ando Y Human mortality

in organophosphate poisonings Vet Hum Toxicol

1997 3984ndash8511 Abdollahi M Jalali N Sabzevari O Hoseini R

Ghanea T A retrospective study of poisoning in

Tehran J Toxicol Clin Toxicol 1997 35387ndash39312 Yen DH Yien HW Wang LM Lee CH Chan SH

Spectral analysis of systemic arterial pressure and

346 Munidasa et al

Clin

ical

Tox

icol

ogy

Dow

nloa

ded

from

info

rmah

ealth

care

com

by

Uni

vers

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ater

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028

14

For

pers

onal

use

onl

y

heart rate signals of patients with acute respiratory

failure induced by severe organophosphate poi-

soning Crit Care Med 2000 282805ndash281113 Chuang FR Jang SW Lin JL Chern MS Chen JB

Hsu KT QTc prolongation indicates a poor

prognosis in patients with organophophate poison-

ing Am J Emerg Med 1996 14451ndash453

14 Lee P Tai DY Clinical features of patients with

acute organophosphate poisoning requiring inten-

sive care Intensive Care Med 2001 27694ndash69915 Povoa R Cardoso SH Luna Filho B Ferreira

Filho C Ferreira M Ferreira C Organophosphate

poisoning and myocardial necrosis Arq Bras

Cardiol 1997 68377ndash380

Submitted October 28 2003Accepted January 29 2004

Survival Pattern in Patients with Acute OP Poisoning 347

Clin

ical

Tox

icol

ogy

Dow

nloa

ded

from

info

rmah

ealth

care

com

by

Uni

vers

ity o

f W

ater

loo

on 1

028

14

For

pers

onal

use

onl

y

heart rate signals of patients with acute respiratory

failure induced by severe organophosphate poi-

soning Crit Care Med 2000 282805ndash281113 Chuang FR Jang SW Lin JL Chern MS Chen JB

Hsu KT QTc prolongation indicates a poor

prognosis in patients with organophophate poison-

ing Am J Emerg Med 1996 14451ndash453

14 Lee P Tai DY Clinical features of patients with

acute organophosphate poisoning requiring inten-

sive care Intensive Care Med 2001 27694ndash69915 Povoa R Cardoso SH Luna Filho B Ferreira

Filho C Ferreira M Ferreira C Organophosphate

poisoning and myocardial necrosis Arq Bras

Cardiol 1997 68377ndash380

Submitted October 28 2003Accepted January 29 2004

Survival Pattern in Patients with Acute OP Poisoning 347

Clin

ical

Tox

icol

ogy

Dow

nloa

ded

from

info

rmah

ealth

care

com

by

Uni

vers

ity o

f W

ater

loo

on 1

028

14

For

pers

onal

use

onl

y