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David handbook of emergency medicine.indd Sample Chapter

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  • 1. SECTION I Life-threatening Emergencies Chapter 1 Airway Obstruction Airway obstruction is an absolute emergency. AETIOLOGY Trauma, epiglottitis, laryngotracheitis, angioneu- rotic oedema, foreign bodies, neck masses (tumours, abscesses, goitre, etc.), congenital abnormalities and bilateral vocal cord palsy (Fig. 1.1). PRESENTATION ● Stridor and dyspnoea. ● Hoarseness, dysphonia, dysarthria and dysphagia. Examination must be brief, but careful. Sitting up is usually preferred. INTERVENTION ● Administer oxygen by mask: 8 L/min. ● Establish IV line. Administer Inj. Adrenaline 0.3–0.5 mg IV, diluted in 5 ml Normal Saline. ● Monitor progress with pulse oximetry. Plan endotra- cheal intubation, if the progress is not satisfactory. ● Look in the mouth and pharynx (omit this step if it causes distress). Examine neck and chest. ● Do not leave patient unattended.Handbook of Emergency Medicine.indd 1 5/30/2012 4:44:28 P
  • 2. HANDBOOK OF EMERGENCY MEDICINE Hard palate Soft palate Palatine tonsil Tongue Epiglottis Vocal fold Trachea Fig. 1.1 Cross section of the throat showing the narrow space at the back of the tongue, which can easily be obstructed. Intervention Definitive treatment depends on cause. ● Foreign body: Remove with suction/Magill forceps. Administer Heimlich manoeuvre – Thump the back/chest of the child rapidly for about four times, in the head down/upside down position. ● Trauma: Intubation/surgical airway. ● Angioneurotic oedema: Administer Inj. Adrenaline 0.3–0.5 mg IV diluted in 5 ml Normal Saline. Plan early endotracheal intubation. ● Croup: Deliver 3–5 mg Inj. Adrenaline through nebuliser mask; repeat as needed. ● Epiglottitis: Endotracheal intubation with inha- lation anaesthesia in Operation Theatre or ICU by the anaesthetist (refer to Section on Paediatric Emergencies). 2dbook of Emergency Medicine.indd 2 5/30/2012 4:44:30 PM
  • 3. LIFE-THREATENING EMERGENCIES Caveat: Upsetting a child with epiglottitis will worsen obstruction. Allow the patient to position him/herself. Chapter 2 Anaphylaxis Anaphylaxis follows exposure to a wide range of allergens, which include antibiotics (e.g. Penicillins), NSAIDs (e.g. Aspirin), streptokinase, vaccines, nuts, shellfish, bee/wasp, stings, etc. CLINICAL FEATURES Respiratory system: Swelling of upper respiratory tract—occlusion, bronchospasm, dyspnoea and wheeze. CVS: Hypotension, shock, arrhythmia and cardio- respiratory arrest. GI: Nausea, vomiting, diarrhoea and abdominal cramps. Skin: Urticaria, pruritus, erythema and angioedema. MANAGEMENT Airway: Ensure clear airway; if breathing is inade- quate, intubate without hesitation. Breathing: Oxygen by mask 8 L/min; check pulse oximetry. Circulation: Insert 18G IV cannula; check BP; if hypotensive, rapid infusion of Ringer’s Lactate 500 ml. 3Handbook of Emergency Medicine.indd 3 5/30/2012 4:44:30 P
  • 4. HANDBOOK OF EMERGENCY MEDICINE PHARMACOLOGICAL INTERVENTION ● Inj. Adrenaline (1:10000) 0.5 mg (deep IM). If there is evidence of airway compromise (stridor), administer the Adrenaline by IV route. ● Inj. Hydrocortisone 100 mg IV (takes 20 min to act). TM ● Inj. Phenergan 25 mg IV. ● Continuous monitoring for at least 4 hours. Caveat: Some cases are resistant to adrenaline, especially if the patient is taking β-blocking drugs. If adequate doses of adrenaline are not improving the situation, give glucagon 1–2 mg intravenously over 5 min. Chapter 3 Cardiac Arrhythmias ATRIAL FIBRILLATION (AF) Aetiology Rheumatic heart disease, ischaemic heart disease, thyrotoxicosis, COPD, pericarditis and valve disease. Management Cardioversion If the patient is unstable, administer synchronised cardioversion with 50–100 Joules (J). The dosage might need to be increased, if necessary. Premedication ● Inj. Midazolam 0.5–2.0 mg IV bolus. 4dbook of Emergency Medicine.indd 4 5/30/2012 4:44:30 PM
  • 5. LIFE-THREATENING EMERGENCIES ● Inj. Morphine 2–4 mg IV bolus. ● Ensure that the patient is sedated and has been administered adequate analgesia, prior to the procedure. Caveat: Avoid emergency cardioversion, if AF has been persistent for more than 48 hours, unless pharmacological intervention fails and the patient remains unstable. It is better to anticoagulate for 3 weeks; ensure that there is no thrombus in the heart by echocardiogram and then attempt cardioversion. Pharmacological Intervention In a stable patient, for AF with rapid ventricular response, three common options are utilised: ● Inj. Verapamil 2.5–5 mg IV over 2–3 min. It would be prudent to dilute the drug in 10 ml Normal Saline. Repeat after 15 min; if needed, up to a maximum dose of 10–20 mg. Caveat: Do not use Verapamil if the patient has wide QRS complex on ECG or has hypotension. ● Inj. Propranolol 1–3 mg IV over 3–4 min. Repeat similar dose as needed to control the rate up to a maximum dose of 0.1 mg/kg. Propranolol is espe- cially effective in thyrotoxicosis and rheumatic mitral stenosis. Caveat: Do not use if the patient has asthma or CCF. ● Inj. Digoxin 250–500 μg IV over 5 min with 250 μg every 4 hours to maximum of 15 μg/kg in 24 hours. Digoxin, if used alone, may take 11 hours or more to achieve rate control. 5Handbook of Emergency Medicine.indd 5 5/30/2012 4:44:30 P
  • 6. HANDBOOK OF EMERGENCY MEDICINE PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA (PSVT) The heart rate is usually 150–250 beats/min. Aetiology ● No apparent cause. ● May occur with an accessory conduction pathway: Wolff–Parkinson–White (WPW) syndrome. ● Myocardial ischaemia and atrial septal defect. ● Drugs: Amphetamines, cocaine, caffeine, alcohol. Management ● If the patient is unstable: Synchronised cardiover- sion with 50 J, then 100 J, 200 J, 300 J or 360 J, as needed. ● If stable: Vagal manoeuvres, viz. Valsalva’s manoeuvre, carotid massage. Caveat: Do not perform carotid massage if carotid bruit is present. Pharmacological Intervention ● Administer Inj. Adenosine 12 mg IV rapid push followed immediately by 20 ml Normal Saline flush. Most protocols advocate an initial dose of 6 mg and then a subsequent dose of 12 mg. However, the initial use of 12 mg reduces the total cost of Adenosine, if it is effective the first time. The dose of 12 mg may be repeated a second time, if needed. ● If Adenosine fails, administer Inj. Verapamil 2.5–5 mg IV over 2–3 min. Repeat after 15 min to 6dbook of Emergency Medicine.indd 6 5/30/2012 4:44:30 PM
  • 7. LIFE-THREATENING EMERGENCIES maximum of 10–20 mg. (Not be given to patients with wide complex tachycardia or heart failure.) ● If Verapamil fails, administer Inj. Propranolol 1–3 mg IV over 3–4 min. Repeat after 5–10 min, if needed. Aftercare ● Ensure that there is no acute coronary syndrome that has predisposed the patient for the present episode of PSVT. ● Continue with Tab. Verapamil 40–80 mg every 6 hours or Tab. Propranolol 10–30 mg every 6–8 hours (not in WPW patients). Caveat: Do not use Adenosine in WPW syndrome. Look at the ECG carefully and rule out WPW syndrome by ensuring the absence of irregularly irregular, wide complex tachycardia. VENTRICULAR TACHYCARDIA If the Patient is Unstable with Pulse Synchronised cardioversion: 100 J, 200 J, 300 J and 360 J. If the patient is conscious, ensure that pre- medication is administered. If the Patient is Stable Either of the following two options could be used: ● Inj. Amiodarone 150 mg IV over 10 min, followed by continuous IV infusion @ 1 mg/min × 6 hours in 5% Dextrose solution followed by 0.5 mg/min × 18 hours. ● Inj. Lignocaine 1 to 1.5 mg/kg IV bolus. Maintenance infusion is 1–4 mg/min (30–50 mcg/kg/min). 7Handbook of Emergency Medicine.indd 7 5/30/2012 4:44:30 P
  • 8. HANDBOOK OF EMERGENCY MEDICINE Chapter 4 Cardiopulmonary Resuscitation Dictum: Cardiopulmonary resuscitation (CPR) is subjected to frequent revisions. This chapter describes a simplified version of the current ILCOR guidelines (2011), applicable to any setting (Fig. 4.1). CARDIAC ARREST Sudden cessation of cardiac activity, resulting in unconsciousness due to absent cardiac output. Response Check responsiveness by shaking and shouting. Sequence change to chest compressions before rescue breaths (CAB rather than the conventional ABC). Circulation ● Check for carotid pulse: ➢ Pulse present: Open the airway and provide ventilation. ➢ Pulse absent: Begin CPR with 30 compressions to 2 ventilations. ● Continue chest compression 100/min, 2 inches depth. ● Allow complete chest recoil after each compres- sion. ● If multiple personnel are available, rotate the above tasks every 2 min. ● Establish IV access: Insert large-bore IV cannula. 8dbook of Emergency Medicine.indd 8 5/30/2012 4:44:30 PM
  • 9. LIFE-THREATENING EMERGENCIES Airway ● Open the airway, using the head tilt chin lift method, if there are no signs of head or neck trauma. ● Ventilate the patient using bag-and-mask. ● Place an oropharyngeal airway without inter- rupting compressions. This is an acceptable alter- native until endotracheal intubation is performed. ● Endotracheal intubation should take not more than 10 seconds. Breathing ● Deliver each breath over 1 second. ● Give a sufficient tidal volume to produce visible chest rise. ● If there is no advanced airway established, continue 30:2 compression: ventilation ratio. ● Once an advanced airway is established, deliver ventilation at 1 breath/6–8 seconds (8–10 breaths/ min). ● Continue chest compressions without interrup- tion. DEFIBRILLATION ● Chance of survival decreases with increased interval between arrest and defibrillation ● Defibrillation remains the cornerstone therapy for VF and pulseless VT. ● Improved outcome with shorter time between stopping of compressions and shock delivery. ● Biphasic: 120–200 J; Monophasic: Deliver the same strength repeatedly, as needed. 9Handbook of Emergency Medicine.indd 9 5/30/2012 4:44:30 P
  • 10. HANDBOOK OF EMERGENCY MEDICINE ● After shock delivery, the rescuer should imme- diately begin compressions. There should be no pulse or rhythm check at this time. ● Continue for 5 cycles and then check the rhythm. (In in-hospital units with continuous monitoring, e.g. electrocardiography, this sequence may be modified.) Confirm cardiac arrest • Check responsiveness by calling the patient and shaking him, if needed • Shout for help Start CPR • Start chest compression: Depth 5 cm; Rate 100/min • No interruption for breaths • Compression/ventilation ratio 30:2 • If advanced airway is established: 8–10 breaths/min • Attach to Oxygen 10 L/min • Connect to multi-parameter ECG monitor Defibrillation • If monitor shows VF/VT – defibrillate • Energy level – Biphasic defibrillator 200 J; Monophasic defibrillator 360 J Drug therapy • Inj. Adrenaline 1 mg once every 3–5 min IV • Inj. Amiodarone 300 mg IV bolus, for refractory VF/VT Check for reversible causes (3 Hs and 5 Ts) • Hypoxia, hypovolaemia, hydrogen ion abnormality (acidosis) • Tension pneumothorax, tamponade, toxins, thrombosis – pulmonary or coronary Return of spontaneous circulation (ROSC) • Breathing, coughing • Movement • Palpable pulse • Measurable blood pressure Fig. 4.1 Simplified algorithm for CPR. 10dbook of Emergency Medicine.indd 10 5/30/2012 4:44:30 PM
  • 11. LIFE-THREATENING EMERGENCIES Drug Therapy ● Epinephrine IV/IO Dose: 1 mg every 3–5 min. ● Vasopressin IV/IO Dose: 40 units can replace first or second dose of Epinephrine. ● Amiodarone IV/IO Dose: First dose 300 mg; Second dose 150 mg (VT or VF only). Interventions Not Recommended During Cardiac Arrest Atropine, Sodium bicarbonate, Fibrinolytic therapy, Pacing and Precordial thump. Chapter 5 Myocardial Infarction (Acute Coronary Syndrome) Dictum: All patients with chest pain have Acute Coronary Syndrome (ACS) until proven otherwise. Acute cardiac ischaemia encompasses a spectrum of disease processes: ● ST elevation myocardial infarction (STEMI). ● Non-STEMI. ● Unstable angina pectoris. CLINICAL FEATURES History Sudden, severe, constant, crushing, central chest pain radiating to arms, neck, jaw, similar to angina. Associated symptoms include sweating, nausea, vomiting and breathlessness. 11Handbook of Emergency Medicine.indd 11 5/30/2012 4:44:30 P
  • 12. HANDBOOK OF EMERGENCY MEDICINE Caveat: The elderly, diabetics and those with known heart failure can have acute coronary syndrome (ACS) without chest pain. Examination Search for complications of myocardial infarction (MI) [arrhythmia, left ventricular failure (LVF)] and exclude alternative diagnoses [pneumothorax, aortic dissection, pulmonary embolism (PE) and abdom- inal cause]. MANAGEMENT ● Assess and stabilise ABCs. ● Patient should be in propped-up position, unless haemodynamically unstable. ● “ONAM” ➢ Oxygen: By mask 4–6 L/min; pulse oximetry. ➢ Nitroglycerin: Sublingual for symptom relief. Caveat: Hypotension, Sildenafil use. ➢ Aspirin 300 mg, which should be chewed. ➢ Morphine 2.5 mg IV. If pain is persistent, repeat in 10 min interval until the patient is comfort- able; watch for hypotension and respiratory depression. ● Insert IV cannula; check baseline blood counts, electrolytes and cardiac enzymes. ● 12-lead ECG: To confirm STEMI. STEMI ● ST-segment elevation of >1 mm in two contig- uous chest leads or new left bundle branch block 12dbook of Emergency Medicine.indd 12 5/30/2012 4:44:31 PM
  • 13. LIFE-THREATENING EMERGENCIES (LBBB) pattern. (Note that LBBB is presumed new unless there is evidence otherwise.) ● Decide within the next 10 min whether the patient will be treated with thrombolysis or primary percutaneous coronary intervention (PCI). ● Consider thrombolytic therapy with streptokinase, if PCI not feasible (refer to Section on Therapeutics). ● Administer IV Frusemide 40 mg or more, if evidence of LVF present, as required. IV Glyc- eryl Trinitrate is an excellent alternative (refer to Section on Therapeutics). ● In patients with inferior STEMI, right-sided ECG leads should be obtained to screen for ST elevation suggestive of right ventricular (RV) infarction. NSTEMI ST-segment depression or T-wave inversion. ● Commence anticoagulation therapy, utilising unfrac- tionated Heparin or Enoxaparin. Fondaparinux is a reasonable alternative, especially for medically managed patients; this has reduced bleeding risk. ● Reserve Bivalirudin (direct thrombin inhibitor) for patients with known heparin-induced throm- bocytopenia. Adjuvant Therapy ● Tab. Clopidogrel 300 mg. ● Beta blockers: Oral Metoprolol 12.5 mg (if there are no contraindications). ● ACE inhibitors. ● Statins. 13Handbook of Emergency Medicine.indd 13 5/30/2012 4:44:31 P
  • 14. HANDBOOK OF EMERGENCY MEDICINE UNSTABLE ANGINA PECTORIS No ECG or cardiac enzyme abnormality: Observe in the ED and repeat the above steps after 4 hours. Caveats ● ECG might not demonstrate signs of ACS on initial screening, in up to 40% of patients. ● If the initial ECG is not diagnostic of STEMI but the patient remains symptomatic, there is a high possibility of evolving STEMI. ● If the clinical suspicion is high, organise serial ECGs at 5–10 min intervals as well as continuous 12-lead ST-segment monitoring, to detect the potential develop- ment of ST elevation. Chapter 6 Pulmonary Embolism Dictum: ● Suspect pulmonary embolism in unexplained dyspnoea. ● No baseline investigation is diagnostic. ● Start Heparin therapy on suspicion of diagnosis. Pulmonary embolism (PE) is a common and leading cause of death. It often manifests as vague and non- specific symptoms. Hence, the diagnosis is missed more often than it is made. AETIOLOGY Thrombosis in peripheral veins, gynaecologic surgery, major trauma and indwelling venous catheters are 14dbook of Emergency Medicine.indd 14 5/30/2012 4:44:31 PM
  • 15. LIFE-THREATENING EMERGENCIES significant aetiological factors for PE. Also included are pregnancy, puerperium and women on oral contraceptives or hormone replacement therapy. SIGNS AND SYMPTOMS ● Unexplained hypotension. ● The classic triad of signs and symptoms of PE (haemoptysis, dyspnoea and chest pain) occur in < 20% of patients. ● New “adult-onset asthma”, hiccoughs, pleuritic or chest pain aggravated by deep breaths. ● Pulse oximetry is insensitive and could be appar- ently normal. INVESTIGATIONS A. ECG ● The ECG may show no abnormality. ● Tachycardia and non-specific ST–T wave abnor- malities may be present. ● The classic finding of “S1–Q3–T3” is rare. B. Laboratory Studies ● D-dimer by the ELISA method is considered positive if the level is > 500 ng/ml. ● The PO on ABG as well as alveolar–arterial 2 oxygen gradient mismatch has low predictive value. ● The white blood cell (WBC) count may be normal or elevated as high as 20,000/mm3. ● Clotting study results are normal in most patients. 15Handbook of Emergency Medicine.indd 15 5/30/2012 4:44:31 P
  • 16. HANDBOOK OF EMERGENCY MEDICINE C. Imaging Studies 1. Chest X-ray Chest X-ray usually shows no abnormality. Rare findings include: ● Atelectasis, a small pleural effusion or an elevated hemidiaphragm. ● Westermark sign: Dilatation of pulmonary vessels proximal to the embolism along with collapse of distal vessels may be evident. ● Hampton hump: A triangular or rounded pleura- based infiltrate with the apex pointed towards the hilum, located adjacent to the diaphragm. 2. CT Angiography High-resolution CT angiography scan is the preferred primary diagnostic modality. It is non-invasive, easy to perform and offers high sensitivity and specificity. TREATMENT ● Administer Oxygen 10–15 L/min by non- rebreathing mask. ● Propped-up position. ● Avoid fluid overload. ● Administer Inj. Heparin 5000 IU as an IV bolus. ● Send blood investigations for baseline activated partial thromboplastin time (aPTT) and international normalised ratio (INR) and repeat doses of Heparin every 6 hours to maintain an INR of 3. ● Admit the patient in ICU for continuous moni- toring. 16dbook of Emergency Medicine.indd 16 5/30/2012 4:44:31 PM
  • 17. LIFE-THREATENING EMERGENCIES Caveat: Fibrinolytic therapy is the standard treatment for PE. Do not delay anticoagulation while awaiting results of diagnostic tests. Chapter 7 Shock—Clinical Approach Shock is an imbalance between tissue oxygen supply and demand to meet metabolic requirements causing global hypoperfusion. It may exist as compensated (normal blood pressure with inadequate perfusion) or uncompensated (hypotension and inability to maintain normal perfusion). Management intends to restore regional perfusion and improve oxygen delivery, to reverse hypotension and to prevent organ damage from hypoperfusion. CLASSIFICATION AND CAUSES The end results of shock (circulatory collapse and end organ damage) are the same for all types of shock. However, knowing the primary cause facilitates treat- ment (see Table on page 18). CLINICAL APPROACH The clinical approach needs to address two impor- tant goals: (a) To initiate therapy before the shock renders irre- versible damage to end organs; and (b) To determine the cause for shock to initiate definitive management. (See Table on page 19.) 17Handbook of Emergency Medicine.indd 17 5/30/2012 4:44:31 P
  • 18. HANDBOOK OF EMERGENCY MEDICINE Type Physiology Causes Hypovolaemic Decreased Haemorrhage: Trauma, (most common) circulatory gastrointestinal volume dehydration; burns, diarrhoea and vomiting Cardiogenic Impaired heart Acute coronary pump function syndrome, valve failure and dysrhythmias Distributive Pathologic Sepsis, anaphylaxis and peripheral neurogenic blood vessel vasodilatation Obstructive Non-cardiac Pulmonary embolus, obstruction to tension pneumothorax blood flow and tamponade Others Oxidative Adrenal crisis, thyroid cellular Injury storm, toxic cellular toxin DIAGNOSTIC TESTING ● CBC: Blood loss and infection. ● Urea, serum creatinine and electrolytes: Dehydration. ● ECG: Ischaemia, infarction and arrhythmia. ● CXR: Infection and pneumothorax. ● ABG: Hypoxia and acidosis. ● Serum lactate level. ● Blood C/S. ● Urine pregnancy test. ● USG. 18dbook of Emergency Medicine.indd 18 5/30/2012 4:44:31 PM
  • 19. LIFE-THREATENING EMERGENCIES Ask Assess Apply Type of Shock History of Blood loss, Replace blood, Hemorrhagic trauma absent breath needle decom- shock, ten- sound and pression and sion, pneu- elevated JVP pericardiocen- mothorax tesis and cardiac tamponade Evidence of Volume Fluid resusci- Hypovolae- GI bleed or status tation mic shock gastroenteritis Fever Focus of Empirical Septic shock infection antibiotics Chest pain, Ischaemia, Antiarrhyth- Cardiogenic palpitation infraction, mics, throm- shock and risk fac- arrhythmia bolysis, PTCA tors for MI and inotropes Drug inges- Unexplained Decontamina- Adrenal crisis tion and bradycardia tion, antidote and toxic steroid with- and hypoten- and steroid cellular toxin drawal sion replacement Pleuritic Unexplained Thrombolysis Pulmonary chest pain, tachycardia, and anticoagu- embolism shortness of hypotension lation breath and and hypoxia leg swelling Drug intake, Stridor, Adrenaline- Anaphylactic trigger food wheezing IM, corticos- shock and insect and hives teroids and bite antihistamine Severe back Pulsatile Volume Aortic pain abdominal resuscitation aneurysm mass and urgent abdominal CT 19Handbook of Emergency Medicine.indd 19 5/30/2012 4:44:31 P
  • 20. HANDBOOK OF EMERGENCY MEDICINE Caveats ● A patient with normal vital signs may still be in shock. ● Aggressive treatment of the underlying cause of shock decreases morbidity. ● Careful monitoring of fluid status, using a urinary cath- eter and central venous pressure monitoring is essential. 20dbook of Emergency Medicine.indd 20 5/30/2012 4:44:31 PM

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