Important elements in history:
Most reliable in asymptomatic or mildly symptomatic.
Needed to exclude hypoxia
For evidence of aspiration, pulmonary oedema, segmental atelectasis suggesting FB aspiration
May be normal (see Acute Respiratory Distress Syndrome)
If head injury suspected
100% O2 (i.e. 15L O2 non-rebreathing mask)
Intubate at earliest opportunity if necessary
Neck immobilization if face/head injury present or history of diving
---> If ABG and Xray normal, discharge after 6-8 hours of obs.
---> If symptoms improve, and ABG and Xray are normal, discharge after 6-8 hours of close obs.
---> If history of significant immersion, keep for longer
Patients requiring intubation or those with cardiopulmonary compromise
---> ICU admission
Discharged patients must return immediately if they develop dyspnoea, cough, or fever.
PEEP has been shown to improve ventilation
[By shifting interstitial pulmonary water into the capillaries]
[By increasing lung volume via delayed airway closure during expiration]
[By increasing the diameter of airways to improve ventilation]
Cough and bronchospasm
---> treat aggressively with nebulised salbutamol
Endotracheal intubation (and PEEP) may be required when
Urinary catheter placement
Warm peritoneal lavage in severely hypothermic patient
Warmed IV fluids
Warmed inspired air
Extracorporeal blood re-warming in severely hypothermic patient
Death is by prolonged hypoxemia
Target organ of injury is the lung. Injury to other systems is secondary to hypoxia and acidosis.
There may be concomitant head or spinal cord injury
Fluid aspiration causes (via vagus) pulmonary vasoconstriction and hypertension.
---> Water moves rapidly across the alveolar-capillary membrane
---> water adds to circulation, surfactant destoryed
---> atelectasis, decreased compliance, V/Q mismatch (up to 75% shunting)
---> Surfactant washout, rapid exudation of plasma
---> decreased compliance, direct alveolar-capillary basement membrane damage
---> V/Q mismatch
Aspiration of vomitus, sand, silt, sewage can lead to
Pulmonary oedema can be:
Relaxation of the airway due to asphyxia can happen
- just before cardiac arrest
- with or after cardiac arrest
When airway relaxes before cardiac arrest, water fills the lung
---> wet drowning (80-90% of cases)
When laryngospasm continues until cardiac arrest, no aspiration
---> dry drowning (10-20% of cases)
Sudden rapid immersion reducing core temp to <30C may have bradycardia, slow metabolism and preferential shunting, which may be protective.
In most immersions, hypothermia is gradual
---> high risk of VF and neurologic injury
---> Thus aggressive rewarming
No resuscitation should be abandoned until the patient has been warmed to at least 30C.
Male:Female - 12:1 for boat-related, 5:1 for non-boat-related
Female children predominate in bath tub drowning
Peak incidence in 2 groups:
<4 year olds
15-24 year olds
Significant complication - ARDS in the 12-24 hours after submersion.
Multiple organ system failure (MOSF)
Acute tubular necrosis (ATN) (secondary to hypoxemia)
Things to revise/add later:
Bibliography: "eMedicine On The Go"