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2019304591050Patho-physiology00Patho-physiology14605004591685Victim’s airway under liquid voluntary breath holding (unless LOC is primary; with ? HR and BP, may get diving reflex) involuntary laryngospasm (secondary to liquid in oropharynx/larynx) hypoxia, hypercarbia, acidosis laryngospasm active respiratory movements but no gas exchange (breathing point, involuntary) worsened hypoxia loss of laryngospasm active breathing of liquid (absence of water aspiration at autopsy means death was not due to drowning; aspiration of water persistent hypoxia, even if ventilation and circulation restored) End pathway = lung: ? airway pressure, bronchoconstriction, pulmonary hypertension (pulmonary vasoconstriction, ? intravascular pressure, interstitial-alveolar fluid shift), shunting, washout of surfactant, alveolar injury, VQ mismatch, abnormal gaseous exchange, severe hypoxia; non-cardiogenic pulmonary oedema, ? pulmonary compliance, formation of protein-rich exudates; aspiration of other material may occur (eg. Vomit, debris); maximum survival is aspiration of 22ml/kg 2Y apnoea (respiratory arrest before cardiac), LOC, ? HR + BP brain injury in 3-10 minutes, multi- organ failure, deathAdditional changes if submersion is in cold water; freshwater denatures surfactant and damages alveolar cells; salt water draws in fluid (but not enough to cause threatening changes in blood volume or electrolytes, may be transient haemodilution), washes out surfactant, causes foam formation; type of fluid aspirated only makes a difference if grossly contaminated; may get hypovolaemia due to hydrostatic effect of H20 on bodyBrain: cerebral oedema CV: usually haemodynamically stableHaematological: haemolysis may occur in freshwaterRenal: occasionally RTAGI: vomiting (up to 80%); May swallow liquid00Victim’s airway under liquid voluntary breath holding (unless LOC is primary; with ? HR and BP, may get diving reflex) involuntary laryngospasm (secondary to liquid in oropharynx/larynx) hypoxia, hypercarbia, acidosis laryngospasm active respiratory movements but no gas exchange (breathing point, involuntary) worsened hypoxia loss of laryngospasm active breathing of liquid (absence of water aspiration at autopsy means death was not due to drowning; aspiration of water persistent hypoxia, even if ventilation and circulation restored) End pathway = lung: ? airway pressure, bronchoconstriction, pulmonary hypertension (pulmonary vasoconstriction, ? intravascular pressure, interstitial-alveolar fluid shift), shunting, washout of surfactant, alveolar injury, VQ mismatch, abnormal gaseous exchange, severe hypoxia; non-cardiogenic pulmonary oedema, ? pulmonary compliance, formation of protein-rich exudates; aspiration of other material may occur (eg. Vomit, debris); maximum survival is aspiration of 22ml/kg 2Y apnoea (respiratory arrest before cardiac), LOC, ? HR + BP brain injury in 3-10 minutes, multi- organ failure, deathAdditional changes if submersion is in cold water; freshwater denatures surfactant and damages alveolar cells; salt water draws in fluid (but not enough to cause threatening changes in blood volume or electrolytes, may be transient haemodilution), washes out surfactant, causes foam formation; type of fluid aspirated only makes a difference if grossly contaminated; may get hypovolaemia due to hydrostatic effect of H20 on bodyBrain: cerebral oedema CV: usually haemodynamically stableHaematological: haemolysis may occur in freshwaterRenal: occasionally RTAGI: vomiting (up to 80%); May swallow liquid14605004195445Infant, young adult male, epileptic, overseas visitors, mentally retarded00Infant, young adult male, epileptic, overseas visitors, mentally retarded2019304195445Risk Factors00Risk Factors2019303352165Epidemiology00Epidemiology14605003352166Male:female 5-9:1; 2nd most common cause of accidental death in children; 40-50% drownings aged 0-4yrs (most 1-2yrs); most deaths are teenage boys / toddlers; 20% occurs in bathtub; freshwater > saltwater; alcohol involved in 25-50% adult deaths; incidence of C spine # 0.5% (usually in open water and have history of trauma)00Male:female 5-9:1; 2nd most common cause of accidental death in children; 40-50% drownings aged 0-4yrs (most 1-2yrs); most deaths are teenage boys / toddlers; 20% occurs in bathtub; freshwater > saltwater; alcohol involved in 25-50% adult deaths; incidence of C spine # 0.5% (usually in open water and have history of trauma)201930965200Definitions00Definitions1460500964566Drowning: process resulting in primary respiratory impairment from submersion / immersion in liquid medium; liquid/air interface present at entrance of victim’s airway; may live or dieDrowned: death from drowning; death within 24 hours of submersion in liquid (death after 24 hours is secondary to complications)Immersion: covered in waterImmersion syndrome: sudden cardiac arrest immediately following cold water immersion (due to massive vagal response, marked vasoconstriction VF)Submersion: entire body, including airway, under waterCold water submersion: submersion in water <10°C; survival possible after prolonged submersion, especially if small children, water <2°C, freshwater; due to cooling effect of aspirated fluid on lungs and brainShallow water blackout: LOC during underwater swimming, due to cerebral hypoxiaRecovery syncope: syncope occurring immediately after removal from cold water; due to cold diuresis and ? intravascular volume, loss of external pressure from water; always have patient in prone position00Drowning: process resulting in primary respiratory impairment from submersion / immersion in liquid medium; liquid/air interface present at entrance of victim’s airway; may live or dieDrowned: death from drowning; death within 24 hours of submersion in liquid (death after 24 hours is secondary to complications)Immersion: covered in waterImmersion syndrome: sudden cardiac arrest immediately following cold water immersion (due to massive vagal response, marked vasoconstriction VF)Submersion: entire body, including airway, under waterCold water submersion: submersion in water <10°C; survival possible after prolonged submersion, especially if small children, water <2°C, freshwater; due to cooling effect of aspirated fluid on lungs and brainShallow water blackout: LOC during underwater swimming, due to cerebral hypoxiaRecovery syncope: syncope occurring immediately after removal from cold water; due to cold diuresis and ? intravascular volume, loss of external pressure from water; always have patient in prone position201930330200Drowning00Drowning1911356771640Prognosis00Prognosis14382756772276Death usually due to anoxic brain injury; Patients awake and orientated on arrival in ED survive neurologically intact if management of pulmonary complications successful; if no resus needed, usually normal recovery within 48 hoursGood prognosis: witnessed (short) drowning, <5mins to retrieval, <10mins to CPR, <30mins to spontaneous breathing, ROSC before hospital, pupillary response on arrival, motor response to pain on arrival, no respiratory arrest, GCS >5 on scene, ?hypothermic, freshwater; SaO2 >94%Poor prognosis: male; unwitnessed; prolonged submersion (>25mins); asystole (stop CPR unless young / cold water), fresh water, warm water, prolonged resus before hospital, non-reactive pupils and GCS 5 on arrival, fixed dilated pupils at 6hrs, resus duration >25mins; VT/VF on initial ECG; cardiac/respiratory arrest; of those admitted to ICU, 15% persistent vegetative state; SaO2 <94%Determinants of survival: time submerged (possible non-survival if >10mins submersion); water T; efficiency of initial resusTime of 1st spontaneous respiratory effort: <15-30mins of rescue = <10% significant neurological deficit; 60- 120mins = 50-80% chance of serious neurological damageGCS: GCS 5 = 80% risk of death / severe deficit; if neurological improvement within 2-6hrs of resus, often little / no neurological deficit; 34% those comatose on arrival will die; of children comatose on arrival, 40% die, 45% survive with normal function, 15% survive with incapacitating brain injuryDelayed death: due to severe hypoxia, ARDS, multi-organ failure, sepsis00Death usually due to anoxic brain injury; Patients awake and orientated on arrival in ED survive neurologically intact if management of pulmonary complications successful; if no resus needed, usually normal recovery within 48 hoursGood prognosis: witnessed (short) drowning, <5mins to retrieval, <10mins to CPR, <30mins to spontaneous breathing, ROSC before hospital, pupillary response on arrival, motor response to pain on arrival, no respiratory arrest, GCS >5 on scene, ?hypothermic, freshwater; SaO2 >94%Poor prognosis: male; unwitnessed; prolonged submersion (>25mins); asystole (stop CPR unless young / cold water), fresh water, warm water, prolonged resus before hospital, non-reactive pupils and GCS 5 on arrival, fixed dilated pupils at 6hrs, resus duration >25mins; VT/VF on initial ECG; cardiac/respiratory arrest; of those admitted to ICU, 15% persistent vegetative state; SaO2 <94%Determinants of survival: time submerged (possible non-survival if >10mins submersion); water T; efficiency of initial resusTime of 1st spontaneous respiratory effort: <15-30mins of rescue = <10% significant neurological deficit; 60- 120mins = 50-80% chance of serious neurological damageGCS: GCS 5 = 80% risk of death / severe deficit; if neurological improvement within 2-6hrs of resus, often little / no neurological deficit; 34% those comatose on arrival will die; of children comatose on arrival, 40% die, 45% survive with normal function, 15% survive with incapacitating brain injuryDelayed death: due to severe hypoxia, ARDS, multi-organ failure, sepsis1911352497455Management00Management14382752497455Category A (see below): symptomatic treatment; observe at least 6 hours (beware non-cardiogenic pulmonary oedema); NBM; O2 PRN Bring to hospital if: EMS notification, amnesia of event, ? LOC, observed period of apnoeaCategory B+C: C spine immobilisation if: history of diving, use of water slide, MVA, signs of injury, ETOHA: aggressive resus at scene (respiratory support most important)Intubate if: not responding to O2 and CPAP (requiring Fi O2 >40-60% to attain pO2 >60/80; use PSV starting at 10cm, PEEP 5-7.5cm, titrate to maintain SaO2 >95% using lowest possible FiO2; wean ASAP to prevent barotraumaB: beta agonists for bronchospasm; high flow O2 to SaO2 >95%, period of PPV (may require high PEEPs)C: N saline IVF resus (but beware pulmonary oedema); monitor electrolytes; use invasive monitoring if concern; vasopressor PRND: treat seizures; maintain normoglycaemia; rewarm if neededICP monitor if: persistent coma despite correction of reversible causes; target pCO2 25-30 if ? ICPInduced hypothermia if: comatose with spontaneous circulation; do not actively warm to >32-34°C; if >34°C, aim 32-34°C ASAP and maintain for 12-24 hours; prevent hyperthermia; more rapidly cooled = better chance of resusNG if: ? LOCAntibiotics if: features of infection develop (broad spectrum if grossly contaminated water, 2nd generation cephalosporin, anti-pseudomonal if in spa, chemical pneumonitis if swimming pool, sand pneumonitis if salt water; gram -ive, anaerobes, staph, fungi, algae, protozoa, aeromonas if freshwater); correct electrolyte abnormality / coagulopathyNot useful: steroidsStop resus if: persistent apnoea and asystole after 1 hour CPR provided not hypothermic; K >11Discharge advice: return to hospital if fever, change in mental status, respiratory symptoms00Category A (see below): symptomatic treatment; observe at least 6 hours (beware non-cardiogenic pulmonary oedema); NBM; O2 PRN Bring to hospital if: EMS notification, amnesia of event, ? LOC, observed period of apnoeaCategory B+C: C spine immobilisation if: history of diving, use of water slide, MVA, signs of injury, ETOHA: aggressive resus at scene (respiratory support most important)Intubate if: not responding to O2 and CPAP (requiring Fi O2 >40-60% to attain pO2 >60/80; use PSV starting at 10cm, PEEP 5-7.5cm, titrate to maintain SaO2 >95% using lowest possible FiO2; wean ASAP to prevent barotraumaB: beta agonists for bronchospasm; high flow O2 to SaO2 >95%, period of PPV (may require high PEEPs)C: N saline IVF resus (but beware pulmonary oedema); monitor electrolytes; use invasive monitoring if concern; vasopressor PRND: treat seizures; maintain normoglycaemia; rewarm if neededICP monitor if: persistent coma despite correction of reversible causes; target pCO2 25-30 if ? ICPInduced hypothermia if: comatose with spontaneous circulation; do not actively warm to >32-34°C; if >34°C, aim 32-34°C ASAP and maintain for 12-24 hours; prevent hyperthermia; more rapidly cooled = better chance of resusNG if: ? LOCAntibiotics if: features of infection develop (broad spectrum if grossly contaminated water, 2nd generation cephalosporin, anti-pseudomonal if in spa, chemical pneumonitis if swimming pool, sand pneumonitis if salt water; gram -ive, anaerobes, staph, fungi, algae, protozoa, aeromonas if freshwater); correct electrolyte abnormality / coagulopathyNot useful: steroidsStop resus if: persistent apnoea and asystole after 1 hour CPR provided not hypothermic; K >11Discharge advice: return to hospital if fever, change in mental status, respiratory symptoms825502498090191135330200Assessment00Assessment1438275330201History: Look for precipitating event (eg. ETOH, seizure, trauma, syncope); Type and T of water, contamination of water; Time of submersion, time of removal; LOC on removal from water; bystander resus info; time of EMS arrival; obs on arrival of EMS; vomiting during resus; transportation time; 1st spontaneous breath, ROSC; history of vomiting / injury; PMH; consider NAI; psych history; remember prognostic criteria on assessment questions (see below)Examination: pulmonary oedema, T, ECG, injuries (HI, C spine), repeat neurological exam; look for precipitating causeInvestigation: ABG, U+E, osmolarity, ETOH, coagulation (may get coagulopathy), FBC, CK, BSL, lactate; ECG; CXR – usually abnormal, non-cardiogenic pulmonary oedema; C spine XR; CT head (if focal signs / significant trauma suspected); investigations only needed if mod/severeSalt water haemoconcentration, ?Na and K Fresh water transient haemodilution, haemolysis, ? Na00History: Look for precipitating event (eg. ETOH, seizure, trauma, syncope); Type and T of water, contamination of water; Time of submersion, time of removal; LOC on removal from water; bystander resus info; time of EMS arrival; obs on arrival of EMS; vomiting during resus; transportation time; 1st spontaneous breath, ROSC; history of vomiting / injury; PMH; consider NAI; psych history; remember prognostic criteria on assessment questions (see below)Examination: pulmonary oedema, T, ECG, injuries (HI, C spine), repeat neurological exam; look for precipitating causeInvestigation: ABG, U+E, osmolarity, ETOH, coagulation (may get coagulopathy), FBC, CK, BSL, lactate; ECG; CXR – usually abnormal, non-cardiogenic pulmonary oedema; C spine XR; CT head (if focal signs / significant trauma suspected); investigations only needed if mod/severeSalt water haemoconcentration, ?Na and K Fresh water transient haemodilution, haemolysis, ? Na258445329565Prognosis Scales00Prognosis Scales1516380329565Conn and Modell classification - performed at 2 hours following initial immersion Category A GCS 14-15 / awake 100% good outcome Category B GCS 8-13 / conscious but obtunded 100% good outcome Category C GCS 6-7 >90% good outcome C1 GCS 5 / Decorticate >90% good outcome C2 GCS 4 / decerebrate >90% good outcome C3 GCS 3 / flaccid <20% good outcomeOrlowski scale: 90% change good recovery if <3, 5% if >3 Age <3yrs Estimated submersion >5mins No resus inf 1st 10mins of rescue Coma on arrival in ED Metabolic acidosis <7.1 on arrival00Conn and Modell classification - performed at 2 hours following initial immersion Category A GCS 14-15 / awake 100% good outcome Category B GCS 8-13 / conscious but obtunded 100% good outcome Category C GCS 6-7 >90% good outcome C1 GCS 5 / Decorticate >90% good outcome C2 GCS 4 / decerebrate >90% good outcome C3 GCS 3 / flaccid <20% good outcomeOrlowski scale: 90% change good recovery if <3, 5% if >3 Age <3yrs Estimated submersion >5mins No resus inf 1st 10mins of rescue Coma on arrival in ED Metabolic acidosis <7.1 on arrival ................
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