1、 Medical Emergencies 1.Airway emergencies 2.Heat-induced injury 3.Overdoses Overviews1.Airway emergencies Acute upper airway obstructionn Pneumothoraxn Near-drowningAcute upper airway obstruction1.General principals 1.1Etiology .In awake patients-a foreign body,angioedema .In unconscious patients to
2、ngue,foreign body,trauma,infection,angioedema2.Diagnosis 2.1 Clinical presentation 2.1.1 History commonly unavailable 2.1.2 Physical examination Conscious patient:stridor,impaired phonation,sternal or suprasternal retraction,choking sign,repiratory distress Unconscious patient:labored breathing,apne
3、a,difficult ventilation -All patient look for urticaria,angioedema,fever,and evidence of trauma -partial obstruction in the awake patient with adequate ventilation:looking for airway swelling,trismus,pharyngeal obstruction,respiratory retractions,stridor,neck mass.-airway obstruction in an unconscio
4、us patient without intact ventilation:examine the upper airway visually for evidence of obstruction.2.2 Differential diagnosis -trauma to the face and neck,foreign body,infection,tumor,angioedema,laryngospasm.2.3 Diagnostic testing 2.3.1 Imaging:partial obstruction in the awake patient with adequate
5、 ventilation:-Radiography of the neck(PA,L view):perofrmed in ER -rapid CT:2.4 Diagnostic procedures partial obstruction in the awake patient with adequate ventilation:-indirect laryngoscopy -fiberoptic nasopharyngolaryngoscopy 3.Treatment:prevent CA 3.1 Nonsurgical management 3.1.1 Awake patient wi
6、thout ventilation:-Heimlich maneuver -a second technique(back slaps,chest thrusts)3.1.2 Unconscious patient without ventilation:-head tilt-chin lift maneuver or a jaw thrust -oral or nasal airway -ventilate BVM -laryngoscope to remove FB -the supine Heimlich maneuver or chest thrust3.2 Surgical mana
7、gement .Airway obstruction in an unconscious patient without intact ventilation:-direct laryngoscopy and endotracheal intubation-a surgical airway-cricothyrotomy using 12-14G catheter with high-flow O21.Airway emergencies n Acute upper airway obstruction Pneumothoraxn Near-drowningPneumothorax1.Gene
8、ral principals -primary spontaneous pneumothorax -secondary spontaneous pneumothorax -traumatic pneumothorax -latrogenic pneumothorax -Tension pneumothorax:hypotension,respiratory distress2.Diagnosis 2.1 Clinical presentation 2.1.1 History acute onset of ipsilateral chest or shoulder pain a history
9、of recent chest trauma or medical procedure dyspnea 2.1.2 Physical examination decreased breath sounds,decreased vocal fremitus,a more resonant percussion note -tachypnea,respiratory distress,larger and relatively immobile hemithorax severe distress,diaphoresis,cyanosis,and hypotension subcutaneous
10、emphysema2.2 Diagnostic testing 2.2.1 ECG -diminished anterior QRS amplitude and an anterior axis shift,electromechanical dissociation 2.2.2 Imaging chest radiograph:-a separation of the pleural shadow from the chest wall -caution for mechanically ventilated patients -mediastinal and tracheal shift,
11、depression of ipsilateral diaphragm3.Treatment -depends on cause,size,and degree of physiologic derangement 3.1 Primary pneumothorax -resolve without intervention(10 dys for 15%)-discharge,-administer high-flow oxygen(small,mildly symptomatic)-insert a thoracostomy tube(larger than 15%20%,symptomati
12、c)-pleural sclerosis3.2 Secondary pneumothorax -symptomatic and require lung reexpasion -thoracostomy tube and suction required -consult a pulmonologist -surgery for persistent air leak 3.3 Iatrogenic pneumothorax -managed conservatively,admit the patient,administer oxygen,and repeat the chest radio
13、graph in 6 hours -a pneumothorax catheter with aspiration or a one-way valve -managed with a chest tube and suction3.4 Tension pneumothorax -decompress the affected hemithorax immediately with a 14-gauge needle attached to a fluid-filled syringe -seal any chest wound with an occlusive dressing -arra
14、nge for placement of a thoracostomy tube1.Airway emergenciesn Acute upper airway obstructionn Pneumothorax Near-drowningNear-drowning1.General principals 1.1Definition -defined as the survival for at least 24 hours after submersion in a liquid medium -risk factors:youth,inability to swim,alcohol and
15、 drug use,barotrauma,head and neck trauma,epilepsy,syncope.-freshwater drowning and saltwater drowning:-differences:pathophysiology -common:hypoxemia and tissue hypoxia(related to V/Q mismatch,acidosis,and hypoxic brain injury with cerebral edema),hypothermia,pneumonia2.Diagnosis 2.1 Clinical presen
16、tation 2.1.1 Laboratories -serum electrolytes,CBC,ABGs -obtain blood alcohol level and drug screen if the mental status is not normal 2.1.2 ECG -monitor the cardiac rhythm continuously3.Treatment 3.1 Resuscitation -airway management and ventilation with 100%oxygen -IV line with 0.9%saline or lactate
17、d Ringer solution -immobilize the cervical spine,as trauma may be present -treat hypothermia vigorously3.2 Medication -reserve antibiotics for documented infection -prophylactic glucocorticoids have no role4.Complications 4.1 Cerebral edema -occurs suddenly within the first 24 hours and is a major c
18、ause of death -treatment does not appear to increase survival -nevertheless,if occurs,hyperventilate the patient to a PCO2 not lower than 25 mm Hg and administer mannitol or furosemide -treat seizures aggressively with phenytoin -Routine administration of glucocorticoids,hypothermia or barbiturate c
19、oma is not recommended -sedate the patient to reduce oxygen consumption4.2 Pulmonary complications -administer 100%oxygen initially,titrating thereafter by ABGs -intubate the patient endotracheally and begin mechanical ventilation with PEEP -administer bronchodilators if bronchospasm is present -Art
20、ificial surfactant not useful 4.3 Metabolic complications -manage metabolic acidosis with mechanical ventilation,sodium bicarbonate,and BP support4.4 Disposition -admit patients who have survived severe episodes of near-drowning to an ICU -admit any patient with pulmonary signs or symptoms(cough,bro
21、nchospasm,abnormal ABGs or oxygen saturation,or chest radiograph)-observe the asymptomatic patient with a questionable or brief water immersion for 4-6 hours and discharge the patient if the chest radiograph and ABGs are normal2.Heat-induced injuryn Heat crampn Heat exhaustion .Heat syncope Heat str
22、oke Heat stroke 1.General principals 1.1 Classic heat stroke -core temperatures higher than 40.5 -comatose and anhidrotic -those at risk:patients who are chronically ill,dehydrated,elderly,or obese;those who abuse alcohol;and those who use sedatives,hypnotics,or antipsychotics.1.2 Exertional heat st
23、roke -occurs in unacclimatized individuals who exercise in conditions of high ambient temperature and humidity -those at risk:athletes,soldiers,and laborers,particularly if they lack to water -more likely to have DIC,lactic acidosis,and rhabdomyolysis2.Diagnosis based on -the history of exposure or
24、exercise -a core temperature usually of 40.6 or higher -and changes in mental status ranging from confusion to delirium and coma 2.1 Differential diagnosis -malignant hyperthermia -anticholinergic poisoning -Sympathomimetic toxicity -severe hyperthyroidism -sepsis -meningitis -cerebral malaria -ence
25、phalitis -hypothalamic dysfunction due to hemorrhage -Brain abscess 2.2 Diagnostic testing 2.2.1 laboratories -CBC -partial thromboplastin time and prothrombin time -glucose -electrolytes -BUN and creatinine -LDH and CK -ABGs -ECG2.2.2 Imaging if a CNS etiology is considered likely,-CT imaging -spin
26、al fluid examination3.Treatment Immediate cooling is necessary.-wrap the patient in iced sheets -mist the patient with tepid water(20-25)-cool the patient with a large electric fan -ice packs placed at the groin,axillae,and chest -gastric lavage with ice water -discontinue cooling measures when the
27、core temperatures reaches 39,which should be achieved within 30minDantrolene sodium not effectiveTreat severe hypertension,nitroprusside preferableRelieve shivering and vasoconstrictionMonitor core temperatureTreat hypotension,avoid pure a-adrenergic agents4.Complications -rhabdomyolysis:adequate vo
28、lume replacement,manitol and bicarbonate -ARDS -seizures -hepatic injury -congestive heart failure -coagulopathy 3.Overdoses Overdose,General*n Acetaminophen*n Benzodiazepines*n Ethanol*n Colchicinen NSAIDsn Opioidsn CCB .Overdose,General1.General principals 1.1 Definition A toxidrome,or toxic syndr
29、ome,is a constellation of clinical examination findings that assists in the diagnosis and treatment of the patient who presents with an exposure to an unknown agent.1.2 Classification There are 5 general toxidromes that encompass a variety of xenobiotic exposures.1.2.1 Sympathomimetic -hypertension
30、-tachycardia -pupillary dilatation -diaphoresis -drugs:cocaine,amphetamines1.2.2 Cholinergic -bradycardia -respiratory depression,bronchoconstriction and bronchorrhea,decreased oxygen saturations -pinpoint pupils,lacrimation,salivation -urination,defecation,gastrointestinal distress,emesis -fascicul
31、ations and paralysis -agents:organophosphate insecticides,nerve gases 1.2.3 Anticholinergic -tachycardia -hyperthermia -mydriasis,dry,flushed skin,urinary retention,decreased intestinal motility -CNS:agitation,delirium -agents:atropine,scopolamine,and antihistamines 1.2.4 Opiate -respiratory depress
32、ion,oxygen desaturations -miosis -decreased gastrointestinal motility -coma1.2.5 Sedative hypnotic -sedation,coma -rarely respiratory compromise -agents:benzodiazepines2.Diagnosis 2.1 Diagnostic testing 2.1.1 Laboratories -finger stick -chemistry(bicarbonate,creatinine,.)-blood gas(ABGs and VBGs)-se
33、rum drug screen:acetaminophen,salicylate,ethanol -urine drug screen:opioids,cocaine,amphetamines,cannabinoid,benzodiazepine,pcp 2.1.2 ECG -The important cardiac toxins tend to prolong the PR interval,the QRS,or the QT interval 2.1.3 Imaging -In general,there is a limited role of diagnostic imaging i
34、n toxicology -The most useful imaging study in overdoses is the abdominal radiograph3.Treatment It is crucial to maintain the airway,check for adequacy of breathing and circulation,and check a finger stick blood glucose in the patient with coma.3.1 Prevention of absorption -gastric emptying by induc
35、ing emesis or lavage -activated charcoal(AC):1g/kg BW -whole-bowel irrigation -cathartics:have no role3.2 Enhanced elimination -forced diuresis -urinary alkalinization or urinary acidification -hemodialysis and hemoperfusion3.3 Antidotes It will be discussed under specific toxicities.3.4 Disposition
36、 Receive a psychiatric evaluation prior to discharge for certain pts4.Overdoses Overdose,General*Acetaminophen(APAP)*n Benzodiazepines*n Ethanol*n Colchicinen NSAIDsn Opioidsn CCB .Acetaminophen1.General principals -an analgesic,namely APAP,Tylenol,or Paracetamol -often used in cold and flu remedies
37、,the treatment of fevers,headaches,and acute and chronic pain -often sold in combination preparations together with NSAIDs,opiate analgesics,or sedatives -the recommended maximum dose for adults:4 g/d1.1 Epidemiology -the leading cause of toxicologic fatalities in the US -APAP-induced hepatotoxicity
38、 is the most frequent cause of acute liver failure in the US1.2 Etiology Unintentional overdosing is much more common than intentional ingestion in suicide attempts,especially in elderly patients on chronic pain.1.3 Pathophysiology -Absorption:-APAP serum levels peak 30-60 min after oral ingestion;-
39、Absorption is often delayed in overdose and peak levels are usually reached after 2-8 h.-Overdose:-The hepatic conjugation pathways become saturated in overdose;-A cascade of biochemical changes occurs in the liver and centrilobular cell necrosis results.1.4 Risk factors -decreased glutathione store
40、s(fasting,malnutrition,anorexia nervosa,chronic alcoholism,febrile illness,chronic disease)-P450 enzyme inducers(ethanol,INH,phenytion and other anticonvulsants,barbiturates,smoking)2.Diagnosis 2.1 Clinical presentation 2.1.1 First 24 hours asymptomatic 2.1.2 24-48 hours hepatotoxic stage:-RUQ tende
41、rness -transaminitis,bilirubinemia,and elevated PT/INR 2.1.3 2-4 days fulminant hepatic failure stage:-hepatic enzyme elevation along with jaundice -coagulopathy with high risk of spontaneous bleeding -hypoglycemia -anuria -cerebral edema 2.1.4 4-14 days recovery stage2.2 History -a reliable time of
42、 ingestion -the amount,form(combination preparations or extended-release form),period of time -inquire about other coingestants(alcohol,other drugs,other medications)2.3 Physical examination Assess airway,breathing,and circulations and mental status.2.4 Diagnostic criteria -150mg/kg is the potential
43、ly toxic limit that requires therapeutic intervention.-Obtain an APAP serum level at 4h or later after ingestion -Plot the APAP concentration on the Rumack-Matthew nomogram to assess the possibility of hepatic toxicity.-prognostic markers to predict the probability of progressive liver failure:-PH10
44、0,creatinine3.3 mmol/L,severe hepatic encephalopathy(3-4)-serum phosphate 1.2mmol/L on days 2-4(additional criterion)-arterial serum lactate3.0mmol/L after fluid resuscitation(additional criterion)2.5 Diagnostic testing -APAP serum level at 4 h -LFT-AST -PT/INR,serum bicarbonate,blood PH,serum lacta
45、te,renal function panel,and serum phosphate level3.Treatment Gastric lavage is not useful3.1 Activated charcoal -patients with isolated APAP exposure who present less than 4 h after ingestion,1g/kg BW 3.2 NAC(N-acetylcysteine)-a specific antidote to prevent APAP-related hepatotoxicity -It should be
46、administered within 8h after ingestion -IV administration is preferred -IV dosing:-first I h,150mg/kg -thereafter,14mg/kg/hr for 20 hours -Patients with toxic liver failure should be transferred to a transplant center as early as possible.-NAC indications:-patient after acute poisoning with a toxic
47、APAP level according to the nomogram -patients who present beyond 8 h after acute ingestion -patients who present more than 24 h after acute ingestion and still have a detectable serum APAP level or elevated AST -patients with chronic APAP exposure who present with elevated transaminases -patients w
48、ith signs of fulminant hepatic failure4.Complications -hyperglycemia -electrolyte imbalances -GI bleeding -acid-base disturbances -cerebral edema -infections -renal failure4.Overdoses Overdose,General*Acetaminophen*Benzodiazepines*n Ethanol*n Colchicinen NSAIDsn Opioidsn CCB .Benzodiazepines1.Genera
49、l principals -Benzodiazepines have a wide safety margin -Deaths are usually related to the presence of a coingestant or ethanol2.Diagnosis 2.1 Clinical presentation 2.1.1History -difficult to elicit as patients are frequently comatose 2.1.2 Physical examination -typical presentation:coma with normal
50、 vital signs -respiratory depression 2.2 Differential diagnosis -includes:barbiturate overdose,hypoglycemia,ethanol intoxication,and other metabolic causes of coma 2.3 Diagnostic testing 2.3.1 Laboratories -include routine testing for any presentation of coma:dextrose,BMP,hepatic and thyroid functio
