A fatal case of septic tank gas poisoning: Critical care challenges

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Journal of Anesthesia & Critical Care: Open Access
A Fatal Case of Septic Tank Gas Poisoning: Critical Care
Challenges
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Introduction
Septic tanks [1] are enclosed areas made for accumulation
of decomposed domestic wastes, sewerage and its resultant
gases. Sewer gases can be both toxic and non-toxic. Its major
component is Methane [2], which can be extremely toxic in high
concentrations. Sewer gas is a mixture of Hydrogen Sulphide,
Ammonia, Carbon-dioxide, Nitrogen dioxide, Sulphur dioxide
and sometimes, even carbon monoxide. The concentration of
these components differs with the time, sewage composition,
temperature and pH of the contents. Hydrogen sulphide [3] can
be poisonous even in small concentrations in the form of irritation
of the eyes, shortness of breath and incessant cough. Exposure to
higher concentrations can be rapidly fatal. We hereby present a
fatal case of septic tank gas poisoning in a young patient and the
critical care challenges faced.
Case Report
A 24 years old, ASA grade 1, male patient was brought to the
emergency in an unconscious state. There was history of the
patient jumping into a septic tank to save a child who accidentally
fell into the septic tank. As soon as he could evacuate out the child,
he became unconscious and was trapped inside the septic tank

out by neighbours. There was no past history of any illnesses or
allergies or hospitalizations. On examination, the patient was
comatose, hemodynamically stable, with an oxygen saturation of
80% which improved to 90% with supplemental oxygen. In view
of poor GCS (Glasgow Coma Scale) and oxygen desaturation, the
patient was intubated with an 8.5mm cuffed endotracheal tube
and put on assist controlled mode of mechanical ventilation.
       
improved and became 99% on an FiO2 of 80%. His bilateral pupils
were mid-dilated and sluggishly reacting to light. There was no
response to deep painful stimuli. Invasive monitoring with central
venous catheter and arterial line were instituted. Ryles tube
was inserted and nasogastric feeds were started to prevent gut
bacterial translocation. Patient was kept adequately warm and
hypothermia preventive measures were instituted. On the second
day in the intensive care unit, the patient developed decerebrate
posturing. His ABG (arterial blood gas analysis) showed moderate
compensated metabolic acidosis. There was a fall in his urine
output and he also demonstrated spikes of intermittent fever.
There was no improvement in the GCS. All standard supportive
therapies were instituted. Intensive monitoring was continued.
         
Surgical tracheostomy was done due to failure to wean and for
tracheobronchial toilet. His neuro logical condition further
worsened and the patient did not demonstrate any respiratory
efforts of his own. The computed tomographic (CT) scan of
the patient`s brain was suggestive of hypoxic damage. He
also developed hypotension requiring inotropic support and
further oxygen desaturation requiring 100% inspired oxygen
concentration on the fourth day. Finally, the patient succumbed to
septic tank gas poisoning and developed cardiorespiratory arrest

Discussion
Septic tanks are quite common in residential and industrial
areas to cater to sewage wastes. Natural decomposition and
mixture of sewage leads to production of sewage gases. These
gases can be toxic if inhaled in high concentrations or for a
prolonged period of time. Septic tank gases contain methane,
hydrogen sulphide (H2S), carbon dioxide, sulphur dioxide,
ammonia, nitrogen dioxide and traces of carbon monoxide.
Hydrogen sulphide has a characteristic smell of rotten eggs,
Volume 6 Issue 3 - 2016
Assistant Professor, Anesthesia and Intensive care, Dr Ram
Manohar Lohia Hospital and PGIMER, India
*Corresponding author: Uma Hariharan, Fellowship
Oncoanesthesia, Assistant Professor, Department of
Anesthesiology and Intensive care, Dr. Ram Manohar Lohia
Hospital and Post Graduate Institute of Medical Education
and Research, Central Health Services, BH 41, East Shalimar
Bagh, Delhi 110088, New Delhi, India, Tel: +919811271093;
Email:
Received: October 17, 2016 | Published: November 30,
2016
Case Report
J Anesth Crit Care Open Access 2016, 6(3): 00228
Abstract
Deaths due to poisoning continue to haunt the medical practice. Poisoning
could be due to accidental, suicidal or homicidal reasons. Certain poisons do not
have antidotes and can be rapidly fatal. The victims generally succumb either
due to the deleterious effects of the toxic substance per-se or due to secondary
phenomenon or multi-organ failure. Septic tanks are dangerous as they contain
a variety of sewer gases which can be highly toxic when inhaled and result in
various complications, including death. We hereby report a fatal case of accidental
poisoning due to septic tank gases in a young patient and the associated critical
care challenges.
Keywords: Septic tank; Poisoning; Sewer gases; Toxic; Hydrogen Sulfide;
Methane; Fatal

Citation: Hariharan U, Bhasin N, Mittal V, Sood R (2016) A Fatal Case of Septic Tank Gas Poisoning: Critical Care Challenges. J Anesth Crit Care Open
Access 6(3): 00228. DOI: 10.15406/jaccoa.2016.06.00228
A Fatal Case of Septic Tank Gas Poisoning: Critical Care Challenges 2/2
Copyright:
©2016 Hariharan et al.

as a warning signal for sewer gas leakage. It is a colourless gas,
 
concentrations of hydrogen sulphide can cause irritation of the
eyes, sore throat, dyspnea and cough. Prolonged exposure can even
cause pulmonary edema, headache and dizziness [4]. Exposure to
levels > 100ppm (parts per million) can be dangerous as it causes
olfactory fatigue and the smell becomes undetectable. Exposure
to higher concentrations (>300 ppm), results in rapid loss of
consciousness and death. Even a single breath of a concentration
higher than 1000 ppm can cause immediate collapse (‘knock-
down”) and death. The toxicity of H2S is due to inhibition of
oxidative phosphorylation and cytochrome oxidase resulting in
reduction in cellular ATP (adenosine tri-phosphate). Inhalation
leads to a multitude of respiratory complications like organizing
pneumonia and adult respiratory distress syndrome (ARDS).
Exposure to high concentrations of methane can be dangerous as
it reduces percentage of oxygen in the air and causes hypoxia [5].
Methane gas inhalation can cause asphyxia, loss of consciousness
and pneumonitis.
Our patient had entered the septic tank to save a child
accidentally trapped inside it. After evacuating the child, the
patient became unconscious probably due to exposure to high
        
minutes, before he was evacuated by neighbours. He was
brought in a comatose state to the emergency where he was
managed according to standard protocol and given all supportive
treatments. The patient would have already suffered hypoxic
           
antidote to septic tank gas poisoning. Hypoxic injury to brain and
other organs is usually irreversible and hence the patient could
not be saved.
There is paucity of literature on the diagnosis and
management of septic tank gas poisoning. In several areas,
especially developing nations, there are no standard guidelines or
protocols for designing, construction, cleaning and maintenance
of septic tanks. Casualties [6] occurring due to septic tanks may
not even be reported, which may be responsible for the lack of
accurate statistical data on the health hazards caused by them. All
septic tanks should have a display board highlighting the dos and
don’ts as well as the possible hazards due to sewer gases. Only
authorized and trained personnel wearing personal protective
gear should be allowed inside the septic tanks. All necessary
precautions should be taken by the septic tank workers to
prevent themselves and others from getting trapped inside the
septic tanks. The government agencies should formulate special
rules and regulations for safe use and maintenance of septic
tanks. Measures for quick evacuation must be ensured in the
event of any accident. As health professionals, our aim must be
to provide adequate ventilation and oxygenation to the patient,
prevent secondary brain injury, maintain hemodynamic stability
and circumvent multi-organ damage. The general principles
of critical care management consist of administering 100%
oxygen, endotracheal intubation to protect the airway, adequate
ventilation to prevent hypercarbia, ensuring normothermia,
instituting invasive monitoring, regular GCS charting, maintaining
adequate mean arterial pressure and urine output. Hyperbaric
oxygen therapy [7] may be useful in some hemodynamically
       
supportive therapy, amyl nitrite and sodium nitrite inhalation
    
is evacuated early.
Conclusion
Septic tanks continue to be health hazards as they produce
sewer gases which can be toxic to human beings and also cause
greenhouse effect. Septic tank gas poisoning can be fatal if
inhaled in high concentrations or for prolonged periods. Proper
precautions should be taken before entering septic tanks and
all people must be educated about the health hazards of sewer
gases. Hypoxic damage to the vital body organs can be extremely

severe poisoning cases.
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