Differential Diagnoses Flashcards
ddx hypoxia
Pathophysiological Mechanism of Classification:
- Decreased inspired O2
a. Mechanical failure of the anesthesia apparatus to deliver O2 to the patient
b. Disconnection from the oxygen supply
c. Empty O2 cylinder
d. Gas pressure failure
e. Crossing of pipelines
f. Crossing of tanks
g. Fracture or sticking of flow meters
h. Transposition of rotameter tubes
i. Improper oxygen sensor calibration - Hypoventilation
a. Esophageal intubation
b. ETT kink, blockage with secretions, herniated or ruptured cuff
c. Right main-stem intubation
d. Respiratory depression or failure 2/2 to anesthetic medications and paralysis
e. Ventilator failure - Impaired diffusion
- Ventilation-perfusion mismatch
- Right-to-left intracardiac shunt
a. PFO
b. Tetralogy of Fallot - Intrapulmonary derangements
Structural Anatomic Classification:
- Alveoli
a. Pulmonary edema
b. Acute lung injury/pulmonary contusion
c. ARDS
d. Pulmonary hemorrhage
e. Pneumonia - Interstitium
a. Pulmonary fibrosis
b. Viral pneumonia
c. Allergic alveolitis - Heart and pulmonary vasculature
a. Pulmonary Embolism
b. Intracardiac or intrapulmonary shunt
c. Congestive heart failure - Airways
a. Asthma
b. COPD
c. Mucus plugging
d. Right main-stem intubation - Pleura
a. Pleumothorax
b. Pleural effusion
ddx pulse ox inaccuracy
- dyshemoglobins
- vital dyes
- nail polish (greatest effect blue)
4 ambient light - light emitting diode variability
- motion artifact
- background noise
- electrocautery
- loss of signal with hypoperfusion
- black henna
causes of decreased etco2
decrease in metabolic rate: hypothermia, hypothyroidism
change in elimination: increased dead space/copd, hyperventilation, decreased cardiac output/cardiac arrest, decreased co2 production, circuit leak or occlusion, PE (air, thrombus, gas, fat, marrow, amniotic)
other: increased muscle relaxation, increased depth of anesthesia, surgical manipulation of the heart or thoracic vessels, wedging of the PA catheter
causes of increased etco2
increased metabolic rate: increased co2 production (MH, thyrotoxicosis, hyperthyroidism), hyperthermia, shivering/convulsions, sepsis
change in elimination: rebreathing (valve prolapse, failed CO2 absorber), hypoventilation, depression of the respiratory center with a decrease in tidal volume, reduction of ventilation (partial paralysis, neurologic disease, high spinal anesthesia, weakened respiratory muscles, acute respiratory distress), increased or improving cardiac output, right to left intracardiac shunt
other: excessive catecholamine production, admin of lbood/bicarb, release of aortic/arterial clamp or tourniquet with reperfusion to ischemic areas, glucose in the IV fluid, parenteral hyperalimnation, CO2 used to inflate the perritoneal cavity during laparoscopy, pleural cavity during thoracoscopy, or a joint during arthroscopy, sub-q epi injection
causes of minimal to zero etco2 or sudden drop to near zero
equipment malfunction ETT disconnect, obstruction or total occlusion bronchospasm no cardiac output cardiac arrest bilateral pneumothorax massive PE esophageal intubation application of PEEP cricoid pressure occluding the tip of the ETT sudden severe hypotension
errors in capnography
water vapor
disconnect
a-line waveform abnormalities
aortic stenosis - pulsus parvus (narrow pulse pressure) and pulsus tardus (delayed upstroke)
aortic regurgitation - bisferiens pulse (double peak) and wide pulse pressure
hypertrophic cardiomyopathy: spike and dome (midsystolic obstruction)
systolic left ventricular failure: pulsus alternans (alternating pulse pressure amplitude)
cardiac tamponade: pulsus paradoxus (exaggerated decrease in systolic BP during spontaneous inspiration)
hypovolemia: exaggerated decrease in SBP or pulse pressure during mechanical ventilation
PA catheter large a wave ddx
mitral stenosis, atrial myxoma, myocardial ischemia, acute CHF
PA catheter large v wave ddx
mitral regurgitation (pap muscle dysfunction), CHF, MI, VSD
False increase in thermodilution cardiac output readings
small injectate volume
increased temperature of injectate
thrombus on thermister
the patient is in a very low cardiac output state
false decrease in thermodilution cardiac output readings
Large injectate volume
decreased temperature of injectate
inflation cycle of lower limb sequential compression devices
either rapid or continuous infuison of IV fluid thorough the PAC 2/2 to the cooling effect on the blood
Ddx wheezing
Bronchospasm
asthma
COPD
tracheobronchitis
restrictive pulmonary disease: sarcoidosis
rheumatoid arthritis-associated bronchiolitis
extrinsic compression: thoracic aneurysm, mediastinal neoplasm
intrinsic compression: epiglottitis, croup
CHF
PE
mechanical obstruction of the tracheal tube: kinking, secretions, cuff over-inflation
inadequate depeth of anesthesia
endobronchial intubation
pulm aspiration and edema
pneumothorax
Ddx hypotension
- Pulm: hypoxia, hypercarbia, tension pneumothorax
- Hypovolemia: fluid deficit, acute blood loss
- Cardiac: rate/rhythm abnormallity, inotropic failure, myocardial ischemia, contusion, tamponade, rupture, CHF, cardiomyopathy, valvular injury, or lesion
- Shock: hypovolemia, cardiogenic, septic
- Surgical compression of the heart, aorta, IVC or abdominal contents
- Embolus: pulm, air, fat, amniotic
- Electrolyte and hormonal abnormalities: hypoglycemia, hypocalcemia, adrenal insufficiency, anti-diuretic hormone suppression, hypermagnesemia
- Anaphylaxis: latex, transfusion, drugs such as abs, locals, muscle relaxants, opioids, protamine, colloids, iodine, IV contrast dye
- Deep anesthesia, drug overdose, medications (ACE-i, ARBs)
- Hypothermia
- Sympathetic blockade, neuraxial block
- Venodilation
- Laparoscopy: Hypercarbia, dysrhythmia, increased vagal tone from excessive stretching of the peritoneum, compression of the IVC, venous gas embolism
Ddx hypertension
- Pre-existing HTN and end-organ dysfunction of the brain heart and kidneys
- White coat HTN
- Pulmonary: hypoxia, hypercarbia, pulmonary edema, obstructive sleep apnea
- Renal: renovascular disease, renal parenchymal disease, renin-secreting tumor, polycystic kidney disease
- Neurologic: elevated ICP, spinal cord injury, Guillain-Barre syndrome, dysautonomia
- Cardiac: ischemia, stiff vessels, aortic coarctation, fluid overload
- Endocrine: Cushing’s syndrome, pheochromocytoma, thyrotoxicosis, hyperaldosteronism, hyperparathyroidism
- Vascular: coarctation of the aorta, vasculitis, collagen vascular disease
- Drugs: vasopressors, cocaine, monoamine oxidase inhibitors +/- tyramine, tricyclic antidepressants, naloxone, glucocorticoids, mineralcorticoids, oral contraceptives, withdrawal from anti-hypertensive therapy, withdrawal from drugs of abuse
- Pain, anxiety, inadequate anesthesia
- Bladder distention
- Malignant hyperthermia
- Hypothermia
- Electrolye abnormalities: hypercalcemia, hypoglycemia
- Autonomic instability
Ddx bronchospasm
kinked ETT solidified secretion or blood pulmonary edema tension pneumothorax aspiration pneumonitis PE endobronchial intubation persistent cough or strain negative pressure expiration
