Anesthesia Flashcards
Definition of hypotension/shock?
Inadequate tissue perfusion and delivery of oxygen to tissues which can result in ischemia followed by necrosis and lead to end organ damage.
Pathophysiology of hypotension/shock?
Hypotension (BP = CO (SV x HR) x SVR).
o SV decreases in cardiogenic, hypovolemic, adrenal, hypothyroidism and obstructive shock
o SVR decreases in distributive shock (septic, anaphylactic, neurogenic, hepatic)
Early signs of hypotension/shock?
^RR, ^HR, narrow pulse pressure, reduced capillary refill, cool extremities, reduced central venous pressure
Late signs of hypotension/shock?
hypotension + altered mental status, reduced urine output
Estimated SBP Based on Palpable Pulse
RADIAL (>80 SBP), FEMORAL (>70 SBP), CAROTID (>60 SBP)
Approach to shock: Step 1: How stable is the patient?
▪ Airway – Can’t protect airway – choking, stridor, purse lip breathing
▪ Breathing – O2 sats
▪ Circulation – assess skin temperature, measuring capillary refill time (CRT), feel pulses
▪ If patient isn’t stable call a code blue
Approach to shock: Step 2: Get another set of vitals
▪ 6 vitals (including glucose)
▪ Check the JVP!
High = cardiogenic or obstructive
Low = hypovolemic or distributive
Approach to shock: Step 3: OIL the patient
▪ O2
▪ IV
▪ Lines (BP cuff, sat probe, cardiac monitor, foley catheter)
Approach to shock: Step 4: Warm shock vs cold shock
Cold shock (hypovolemic, neurogenic) – Narrow PP, vasoconstricted
Warm shock (sepsis, anaphylaxis) – Wide PP, vasodilated
Investigations for cold shock?
Investigations: Blood work (Cr, lytes), serum lactate (>4 needs to go to ICU)
Investigations for warm shock?
Investigations: Blood cultures, urine cultures
Treatment for cold shock?
Tx: Fluids (20-30 ml per kg) isotonic (crystalloid)– About 1-2L
Treatment for warm shock?
Tx: empiric antibiotics, fluids
What are the causes of shock?
(SHOCKED): Septic/Spinal (neurogenic), Hypovolemic, Obstructive, Cardiogenic, Anaphylactic, Endocrine (e.g. Addisonian crisis, thyrotoxicosis/hypothyroid), Drugs
o Hypovolemic: Intravascular volume loss, hemorrhagic, fluid loss
o Cardiogenic: Arrhythmia, AMI, valvular, cardiomyopathy, pericarditis/PE
o Distributive: Vasodilatory, sepsis, anaphylaxis, neurogenic, drugs, addisons crisis
o Obstructive: Tension PTX, tamponade, PE
o Drugs: vasodilators, high spinal anesthetic interfering with sympathetic outflow
What should be done on physical exam for shock?
▪ General – ABCDE, vital signs (orthostatic VS), GCS
▪ Derm – expose entire body. Examine for signs of trauma, hives, rashes
▪ Extremities - peripheral pulses, skin temperature, capillary refill
▪ HEENT: Inspect for angioedema, central cyanosis, tracheal deviation. JVP assessment
▪ CV/RESP: Inspect for asymmetric chest movement, apnea. Percuss for hyperresonance (pneumothorax), dullness (consolidation, hemothorax). Auscultate for cardiac friction rub, breath sounds, crackles. JVP – distributive/hypovolemic vs cardiogenic/obstructive
▪ URO: urine output
▪ ABDO: Inspect for abdo distension, bruising around umbilicus or flanks. Palpate for rigid/tender abdomen, masses
▪ NEURO: Hyperreflexia, Decrease strength of limbs, lack of sensation in perianal area
Definition of obstructive shock?
Definition: Obstruction of blood into/out of the heart
S/S of obstructive shock?
Increased JVP, distended neck veins, increased systemic vascular resistance, insufficient cardiac output (CO), depending on cause, may see pulsus paradoxus, Kussmaul’s sign, or tracheal deviation. Cool extremities
Causes of obstructive shock?
Tension pneumothorax, cardiac tamponade, pulmonary embolism, other emboli, CHF
Management of obstructive shock?
o General: supplementary oxygen and IV fluids, vasopressors
o Needle Decompression: or tube thoracostomy for tension pneumothorax/hemothorax
o Pericardiocentesis: pericardial tamponade
Definition of cardiogenic shock?
Definition: Heart not being able to produce enough power
Signs of cardiogenic shock?
Low CO, high SVR, high HR, low urine output
o Also get an decrease in ATP and increase in lactic acid (switch to anaerobic). An increase in lactic acid results in increase in protons leading to metabolic acidosis
o Signs of left-sided heart failure (bilateral crackles on chest exam)
Causes of cardiogenic shock?
Myocardial dysfunction, myocarditis, aortic valve stenosis, arrhythmias, dilated cardiomyopathy
Symptoms of cardiogenic shock?
Cool extremities due to peripheral vasoconstriction, cyanosis
Management of cardiogenic shock?
o General: supplementary oxygen and IV access
o Inotropic Agents: vasopressors (epinephrine), dobutamine (positive inotrope)
o Intra-aortic balloon pump: encourage blood flow, alleviate cardiac workload
o MI:
▪ Angioplasty/Stenting: via cardiac catheterization
▪ Thrombolytics: clot busters or fibrinolytics to dissolve clots
▪ Surgery: coronary artery bypass, repair, ventricular assist device, transplant