Based on the very good medical book of Stone C.K., Humphries R.L., Current Diagnosis and Treatment in Emergency Medicine, McGraw Hill - LANGE, 6th edition, 2008.
mcgraw-hillmedical.com

Note: tachycardia may not occur if on β’ blockers!

Investigations on shock

Vitals (pulse, RR respiratory rate, BP, T temperature), glucose finger stick, SaO2 (oxygen saturation), ABGs (arterial blood gases), CXR (Chest X’ Ray), +_ AXR (abdominal X’ Ray), +_ECHOcardiogram/ FAST +_CT.

Labs: CBC/ FBC (complete/ full blood count), urea, creatinine, electrolytes (potassium K, sodium Na, calcium Ca, magnesium Mg, phosphate P), coagulation studies (Plts platelets, PT, APTT, INR, D’ Dimers), LFTs (lever function tests), CK, cardiac enzymes & markers, LDH, ESR, CRP, amylase, lipase, serum lactate, urinalysis, cultures (in suspected sepsis, blood & urine mid stream, faeces – if diarrhoea, throat/ vagina/ sputum wound swab, gram Stain & cultures, sensitivity to antibiotics), pregnancy test (child bearing age women), toxicology (aspirin, paracetamol, illicit drugs etc), drug levels (e.g. anticonvulsives), +_HbCO levels,  +_ TFTs (thyroid function tests), cortisol/ ACTH levels, blood type & crossmatch (ask 4 – 6 units). 

What to rule out on a shock:

A. HYPOVOLAEMIC SHOCK. If the patient is shocked, then has cool and clammy skin (e.g. nose, toes, fingers), tachycardia (> 100 bpm), increased capillary refill time, hypotension (Systolic BP < 90) if blood volume loss is > 30% (> 40% on children!), postural hypotension (drop of Systolic BP> 20 mmHg on standing), confusion, decreased urine output (< 30 ml/h). 

I. BLOOD LOSS

a) Traumatic blood loss.

1. Exsanguination e.g. severe bleeding, scalp lacerations (especially on children) etc.

2. Hemoperitoneum.

3. Haemothorax.

4. Fracture, especially of femur and pelvis. 

Stop any visible haemorrhage, check for bleeding in chest and abdomen. Perform CXR (chest X’ ray), FAST/ ultrasound. Check for pelvic or long bone/ pelvis fracture. If so, do immobilization and consider PAST anti-shock trousers.

b) Non traumatic blood loss.

1. GI (gastrointestinal) bleeding.

2. AAA (Abdominal aortic aneurysm) rapture.

3. Ectopic pregnancy rapture.

Rule out abdominal aortic aneurysm (check for pulsatile abdominal mass and also notice any difference in femoral artery pulses). Do USS/ FAST. Is there haematemesis or melena? Perform PR (per rectum) examination. Is fluid on Levine (nasogastric NG tube) bloody? Perform endoscopy if high suspected GI bleeding.

II. VOLUME LOSS

1. Burns.

2. Heat stroke with dehydration.

3. Skin integrity loss.

4. Vomiting (dehydration).

5. Diarrhoea (dehydration).

6. Decreased fluids intake.

7. DKA (Diabetic ketoacidosis) with dehydration.

8. Third space accumulation e.g. ascites (e.g. on heart failure, nephritic syndrome, protein loss enteropathy, malnutrition).

B. CARDIOGENICSHOCK.  Skin is pale, cool, moist. 

a. Dysrhythmia.

1. Tachyarrhythmia.

2. Bradyarrhythmia.

b. Cardiomyopathy.

1. MI (myocardial infarction).

2. RV (right ventricular) infarction (place leads on right chest! Always on an ECG place a V4R i.e. V4 lead on right). Avoid nitrates! On RV infarction ST elevation on III is > than ST elevation on II, or there is 1mm ST elevation in V4R.

3. Dilated cardiomyopathy

c. Mechanical problems

1. Aortic regurgitation from aortic dissection.

2. Papillary muscle rapture after a MI (heart attack).

i. Ventricular aneurysm rupture.

ii. Free wall ventricular rupture.

Place on monitor (in Europe Right for Red, YelLow for Left and Green for splEen) & perform a 12 lead ECG. Cardiovert any unstable tachyarrhythmia. Place transcutaneous pacing for unstable bradyarrhythmia (until official IV pacing, if recurrence).

For cardiogenic shock give oxygen 100% high flow, consider heparin (e.g. massive PE pulmonary embolism), gentle fluid challenges (250 cc fluids) if no pulmonary oedema. Also consider Glucoprotein IIb/IIIa on MI (myocardial infarction), CPAP or intubation and mechanical ventilation on pulmonary oedema, dopamine and/or dobutamine infusion, intraortic balloon pump, PCI (on MI myocardial infarction), Neseritide (rh – BNP analogue). Consult early a senior cardiologist. L – NMMA is an investigatory drug.

C. DISTRIBUTIVE SHOCK. Skin is warm, red!

1. Anaphylactic shock. Laryngeal oedema, stridor, wheezing, hives, urticaria, angioedema (exclude ACE inhibitors intake and also hereditary angioedema – in the last give FFP fresh frozen plasma or c1 esterase inhibitor). Give IM adrenaline 1: 1000 (adults 0.5 mg IM, children 0.01 mg/kg IM ), fluids (up to 2 L crystalloids), raise legs, give 100% oxygen high flow, give β’ agonists (salbutamol) on wheezing, give H1 (diphenhydramine 25 – 50 mg IV/IM or chlorphenamine 10 mg IV) & H2 blockers, hydrocortisone 200 mg IV.

2. Septic shock. Suspect SIRS (systemic inflammatory response syndrome) it if >_ 2 of the following: T (temperature) > 38 or < 36 degrees C, HR (heart rate) >90, RR (respiratory rate) > 20/min (or hypocapnia), WCC (WBC) > 12000 or < 4000 or > 10% bands. Sepsis is SIRS with infection. Septic shock is sepsis with hypotension (SBP< 90 mmHg) despite fluid resuscitation.

Ιn case of a erythematodous rash exclude TSST1 toxic shock syndrome toxin 1  (toxic shock syndrome may occur after tampon use on women and also on a wound and in prolonged nasal packing).

3. Neurogenic shock (spinal cord lesion, surgery, spinal trauma). On trauma exclude first hypovolaemic shock (bleeding in abdomen, chest) which is commoner. Neurogenic shock is characterized by hypotension, bradycardia (!) and also motor/ sensory level, decreased rectal tone and warm skin.

4. Toxins. Consider decontamination (eyes, skin meticulous washing), clothes removal, antidotes, gastric lavage, whole bowel irritation, active charcoal, dialysis. Opioids and organophosphates will cause small pupils (pinpoint on opioids; pontine haemorrhage causes also pinpoint pupils). CO (carbon monoxide) may cause headache.

5. Drugs – vasodilation e.g. β’ blockers or calcium channel blockers. These may cause shock without tachycardia (especially if given both).

Endocrinological problems

6. Adrenal insufficiency (recent abrupt stop of cortisone, or not increasing it at stress situations such as surgery or trauma).

6. Thyreotoxic coma (it may also cause hyperthermia and AF atrial fibrillation).

7. Myxedema coma (it may also cause hypothermia).

8. Hypoglycemia (it may mimic stroke and cause focal neurological signs such as hemiparesis). Before the official Lab tests, always perform a ward finger stick tests.

9. Hypopituitarism. 

D. OBSTRUCTIVE SHOCK.

1.Tension pneumothorax. Decreased unilateral breath sounds, tracheal deviation (away from the pneumothorax; late sign!), unilateral hyper-resonant – tympani of the hemithorax on percussion, JVD (jugular vein distension – if not hypovolaemic). Don’t wait for a CXR (chest X’ ray)! Perform needle decompression and next insert a chest tube.

2. Pericardial disease.

i. Cardiac Tamponade. JVD (jugular veins distension), muffled heart sounds, Kussmauls’ sign (increase of JVP on inspiration), low ECG voltage, electrical alterance on ECG, pulsus paradoxus (decrease of Systolic BP and pulse on inspiration). Trauma is a common cause. Other causes less common (renal failure - uraemia, lung cancer, TB etc). Perform FAST/ USS (ultrasound).

ii. Constrictive pericarditis.

3. Massive pulmonary embolism (PE). Hypoxemia, right ventricular strain on ECG, acute right ventricular overload, chest pain, cyanosis, syncope, hypotension, tachypnea, tachycardia, JVD (jugular vein distension). Give unfractioned heparin IV. If massive, consider thrombolysis (e.g. with rTPA alteplase) or embolectomy (call a surgeon). Do D’ Dimers. Negative D – Dimers exclude a PE. Check leg & pelvis veins veins for DVT (Deep Vein thrombosis) with a Doppler/ plythysmography.

4. Auto PEEP from mechanical ventilation.

NOTES

·        Warm skin? If so, consider sepsis, neurogenic shock, anaphylactic shock, medication overdose (e.g. β’ or Calcium blockers).

·        Rule out Poisons/ medication overdose or SEs (Side Effects)/ illicit drug abuse, Sepsis and Adrenal Insufficiency.

·        JVD (jugular vein distension): exclude tension pneumothorax, cardiac tamponade, massive PE (pulmonary embolism) and CHF congestive heart failure (for heart failure check for calf edema and fine lung crackles – end respiratory crepitations/ rales especially at lung bases).

• PH of venous blood is usually 0,01 – 0,03 lower than the arterial blood PH. Also PCO2 is 6 mmHg higher and bicarbonate is 2 meq/L higher by using venous blood.

• Anion gap is ([Na] + [K]) – ([Cl] + [HCO3]) and normal values are 12 – 16 mEq/L (usually 10 -1 2mEq/L).  Increased anion gap occurs on DM (diabetes melitus), alcoholics, starvation, lactic acidosis, renal failure, exogenous toxins metabolized to lactate (cyanide – CN, CO, ibuprofen, strychnine, toluene, iron – Fe and INH - isoniazide), or exogenous toxins metabolized to acids (aspirin, methanol, ethanol, ethylene glucol, paraaldeyde and rarely with isopropanol), severe hypotension, seizures and hypoxemia.

• Increased osmolar gap may occur in DKA, ethylene glycole or methanol or ethanol or isopropanol poisoning. Osmolar gap ΔOsm = measured Osm – Calculated O.

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