Drowning

Reviewed and revised 24 May 2014

OVERVIEW

  • Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid (WHO 2002 definition)
  • drowning can be due to — submersion (the airway goes below the level of the surface of the liquid) or — immersion (a liquid is splashed across a person’s face, e.g water-boarding)
  • respiratory impairment must be present for drowning to have occurred
  • terms such as “near drowning,” “dry or wet drowning,” “secondary drowning,” “active and passive drowning,” and “delayed onset of respiratory distress” are no longer used
  • non-fatal drowning: the drowning process is interrupted and the person survives
  • fatal drowning: the person dies during the drowning process (at any stage)

CAUSES

  • misadventure
  • inadequate supervision of small children
  • neurological event e.g. epilepsy, stroke
  • cardiac event e,g, MI, HCM, dysrhythmia, long QT, short QT
  • impaired judgement e.g. intoxication
  • trauma
  • overdose
  • foul play

PATHOPHYSIOLOGY

Sequence of events leading to death

  • water enters the mouth when no longer able to be kept clear
  • voluntarily spat out or swallowed at first
  • next conscious response is to hold one’s breath, lasts ~ 1 minute, until inspiratory drive is too high to resist
  • water is aspirated into the airways, and coughing occurs as a reflex response
  • laryngospasm may occur (rapidly terminated by the onset of brain hypoxia)
  • continued aspiration -> hypoxemia -> loss of consciousness and apnea
  • Final mode of death involves cardiac dysrhythmia: tachycardia -> bradycardia -> PEA -> asystole
  • whole drowning process, from submersion or immersion to cardiac arrest, usually occurs in seconds to a few minutes (>1 hour in unusual cases of hypothermia)

In survivors the longterm morbidity reflects the severity and duration of cerebral anoxia experienced, and the clinical picture is determined predominantly by the amount of water that has been aspirated and its effects.

  • surfactant dysfunction and washout
  • osmotic gradient damages alveolar–capillary membrane: disrupts the integrity of the membrane, increases its permeability, and exacerbates fluid, plasma, and electrolyte shifts
  • often massive bloodstained pulmonary edema
  • results in decreased lung compliance,V/Q mismatch, atelectasis and bronchospasm

Sea water versus fresh water

  • no significant differences in electrolytes abnormalities or degree of lung injury despite differences in osmotic gradient
  • bacterial burden is greater in fresh water (gram negatives, anaerobes, Staphylococci, fungi, algae, protozoans, Aeromonas)

Hypothermia

  • hypothermia associated with drowning can provide a protective mechanism that allows persons to survive prolonged submersion episodes
  • rate of cerebral oxygen consumption is reduced by ~ 5% for each reduction of 1°C in temperature within the range of 37°C to 20°C

COMPLICATIONS

  • laryngospasm
  • aspiration pneumonitis
  • negative pressure pulmonary edema
  • ALI / ARDS
  • ischemic cardiomyopathy
  • arrhythmias
  • hypoxic ischemic encephalopathy
  • MODS
  • hypothermia
  • electrolyte disturbance
  • associated trauma e.g. TBI, spinal cord injury
  • sequelae of underlying causes

MANAGEMENT

Drowning is often associated with hypothermia, so that in the event of cardiac arrest continue resuscitative efforts for longer than usual and attempt to normalised the person’s core temperature as rapidly as possible before ceasing resuscitative efforts

Prehopsital

  • do not attempt CPR in the water — pateints with purely respiratory arrest typically respond following a few rescue breaths, if no response get patient out of the water ASAP
  • only trained individuals should attempt in-water rescue as this is highly dangerous
  • lift patient out horizontal (counters possible sudden circulatory collapse on release of water pressure)
  • remove wet clothing
  • wrap in thick blankets
  • commence basic life support (immediate, uninterrupted CPR)
  • ALS when available
  • maintain c-spine precautions if trauma is possible
  • Heimlich manoeuvre no long recommended

Hospital care

Goals

  • (1) support A, B, C
  • (2) rewarm to 34 C for 24 hrs
  • (3) prevent secondary brain injury
  • NG to decompress stomach
  • passive rewarming: remove wet clothes, insulate with blankets
  • active rewarming: peripheral (forced air warmer, hot water bottles), central (warmed humidified inspired gases, warmed IVF, lavage, intravascular thermal regulation via vascath, haemofiltration, cardiopulmonary bypass)

Management of organ injury

  • NEURO: head up, low normal CO2, MAP of 80mmHg (no need for ICP monitoring), benzodiazepines for seizures, therapeutic hypothermia (actively warm to 34 C), prevent secondary brain injury.
  • RESP: ALI and ARDS -> protective lung ventilation, bronchodilation, iNO, prone, ECMO
  • METABOLIC: severe metabolic acidosis from lactate, in vivo PaO2 in cold patient is much lower than the measured value as it is warmed to 37 C, rhabdomyolysis
  • CARDIOVASCULAR: below 28 C VF is common, extravasation of systemic and pulmonary capillaries + cold diuresis -> hypovolaemia, SIRS post resuscitation, often require cardiac output monitoring
  • INFECTION: consider antibiotics if patient submerged in grossly contaminated water

PREDICTORS OF POOR OUTCOME

Scene

  • immersion > 10 min
  • delay to CPR (e.g. no bystander CPR, unwitnessed)
  • time to first breath
  • water temperature (drop in brain temperature 10C doubles time that brain can survive)
  • presence of cardiac arrest (pulseless or absence of respiratory effort upon rescue)
  • identifiable precipitants; e.g. did the person have a cardiac arrest secondary to an AMI while in the swimming pool?

ED

  • asystole
  • CPR > 25 minutes
  • dilated, non-reactive pupils and pH <7.0
  • dilated, non-reactive pupils and GCS < 5
  • lactate

ICU

  • loss of grey-white matter differentiation on CT within 36 hrs
  • absence of purposeful motor response (GCS < 5) and absence of brainstem reflexes, pupillary response and spontaneous respiration at 24 h

VIDEO

Drowning: Critical Points For Care In The Field – PK SMACCtalk by Andrew Schmidt (2013):


References and Links

Journal articles

  • Layon AJ, Modell JH. Drowning: Update 2009. Anesthesiology. 2009 Jun;110(6):1390-401. PMID: 19417599. [Free Full Text]
  • Schilling UM, Bortolin M. Drowning. Minerva Anestesiol. 2012 Jan;78(1):69-77. MID: 21623341.
  • Szpilman D, Bierens JJ, Handley AJ, Orlowski JP. Drowning. N Engl J Med. 2012 May 31;366(22):2102-10. MID: 22646632. [Free Full Text]
  • Topjian AA, Berg RA, Bierens JJ, Branche CM, Clark RS, Friberg H, Hoedemaekers CW, Holzer M, Katz LM, Knape JT, Kochanek PM, Nadkarni V, van der Hoeven JG, Warner DS. Brain resuscitation in the drowning victim. Neurocrit Care. 2012 Dec;17(3):441-67. doi: 10.1007/s12028-012-9747-4. PMC3677166.

FOAM and web resources


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.