Principles of management of inhaled poisoning

inhalational poisoning occurs when toxic substances are absorbed through the respiratory tract after inhalation of gases, vapors, fumes, aerosols, or particulate matter. because the lungs have a large surface area, thin alveolar membrane, and rich blood supply, inhaled toxins rapidly enter systemic circulation, often producing life-threatening effects within minutes.

Common environments

• house fires

• industrial accidents

• agricultural exposure

• enclosed spaces with combustion

• poorly ventilated homes

Common inhaled toxins

Pathophysiology

Mechanisms of injury

simple asphyxiants

• displace oxygen → hypoxia

• example: methane

chemical asphyxiants

• interfere with cellular respiration

• carbon monoxide: binds hemoglobin

• cyanide: blocks mitochondrial respiration

airway irritants

• airway inflammation and edema

• bronchospasm

• delayed pneumonitis and ARDS

pulmonary toxicants

• alveolar damage

• non-cardiogenic pulmonary edema

Risk factors

• firefighters

• industrial workers

• miners

• agricultural workers (fumigants)

• household exposure in enclosed cooking/heating

• children in poorly ventilated homes

• intentional self-harm

• chemical transport accidents

Clinical features

Early symptoms

• eye irritation

• cough

• throat burning

• dyspnea

• headache

• dizziness

Respiratory signs

• wheezing

• stridor

• tachypnea

• cyanosis

• hoarseness

• pulmonary edema

Neurological

• confusion

• agitation

• ataxia

• seizures

• coma

Systemic

• hypotension

• metabolic acidosis

• cardiac arrhythmias

Diagnostic criteria

suspect inhalational poisoning if:

• exposure in enclosed environment

• multiple victims affected

• soot around mouth/nose

• sudden respiratory distress

• altered consciousness after exposure

Investigations

Bedside

• pulse oximetry (may be misleading in carbon monoxide poisoning)

• blood glucose

Laboratory

• arterial blood gas (ABG)

• carboxyhemoglobin or toxicology screen (if available)

• lactate

• full blood count

• electrolytes

Imaging

• chest x-ray (may be initially normal; repeat at 24 hours)

• CT chest if worsening

Cardiac monitoring

• ECG for arrhythmias

Management principles

treat first — confirm later

Non-pharmacological management

Immediate actions

• move the patient to fresh air immediately

• ensure rescuer safety

• decontaminate clothing

• thoroughly ventilate the exposure area

Airway management

Indications for early intubation

• hoarseness

• facial burns

• stridor

• altered consciousness

• progressive respiratory distress

Breathing support

Oxygen therapy

• mild distress / hypoxia: 24–40% oxygen via nasal cannula at 2–6 L/min

• moderate distress / hypoxia: 24–50% oxygen via face mask or venturi mask at 6–10 L/min

• severe distress / hypoxia: 50–90% oxygen via non-rebreather mask at 10–15 L/min

• apnea: nearly 100% oxygen via bag-valve-mask (BVM) at 10–15 L/min

oxygen should be titrated to saturation targets:

• 94–96% in most patients

• 88–92% in COPD patients

Circulation

• establish IV access

• fluid resuscitation if needed

• cardiac monitoring

• apply CPR if cardiac arrest

Pulmonary care

• humidified oxygen when appropriate

• suction secretions

• chest physiotherapy where indicated

Pharmacological treatment

Bronchodilation

• salbutamol 4 mg PO 6–8 hourly

• salmeterol inhalation (as indicated)

• ipratropium bromide inhalation:

  • 0–5 years: 125–250 micrograms 6–8 hourly (max 1 mg/day)

  • 6–12 years: 250 micrograms 6–8 hourly (max 1 mg/day)

  • 12 years: 250–500 micrograms 6–8 hourly (max 2 mg/day)

Airway inflammation / severe bronchospasm

• adrenaline (SC/IM) 25–50 mg or IV 5–25 mg slowly, repeat every 5–10 minutes if necessary (severe cases only, specialist setting)

• corticosteroids may be considered in selected cases with airway edema

Specific antidotes

Monitoring

observe at least 24–48 hours even if initially stable

watch for delayed complications:

• pulmonary edema

• chemical pneumonitis

• ARDS

Complications

early

• acute respiratory failure

• airway obstruction

• cardiac arrhythmias

late

• bronchiolitis obliterans

• chronic lung disease

• neurocognitive impairment

Prevention

do’s

• ensure proper ventilation during cooking/heating

• use protective masks in industry

• install carbon monoxide detectors

• follow chemical safety protocols

don’ts

• do not burn charcoal indoors

• do not run generators indoors

• do not mix cleaning chemicals

• do not stay in smoke-filled environments