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
ddx fade TOF
med error
profound blockade at time of anticholinesterase admin
abx prolongation
impaired renal excretion of NMBD
other factors that interfere with reversal: hypokalemia, hypocalcemia, hypermagnesemia, metabolic/resp acidosis, Ca channel blockers, hypothermia
anterior mediastinal mass:
shortly after induction but prior to intubation, airway movement ceases, unable to ventilate, ddx
and what would you do
bronchospasm
laryngospasm
soft tissue obstruction
mass compression
OPA
auscultate chest
place in pre-identified best position (mediastinal mass)
minimize head/neck movement (downs)
DL look for laryngospasm; if no laryngospasm then
place ETT and attempt to ventilate; if still unable:
fiberoptic bronch throuh ett assess mass obstruction
if no mass obstruction:
consider severe bronchospasm -> positive pressure vent, deepen anesthetic, administer albuterol and/or epinephrine
If caused by mass obstruction and insufficient time to wake the patient up:
attempt to advance ETT beyond obstruction
consider repositioning
ask surgeon perform emergency sternotomy and manually elevate the mass
ask perfusionist to initiate CPB via fem arteries
ddx dyspnea in PACU
bronchospasm laryngospasm upper airway obstruction NPPE airway edema tracheobronchomalacia exacerbation myasthenia gravis cholinergic crisis pneumothorax atelectasis cardiogenic pulmonary edema inadequate pain control PE residual drug effects mass obstruction
causes of pulm edema
cardiogenic: CAD, poorly controlled HTN, valvular dz, cardiomyopathy
noncardiogenic: aspiration, neurogenic pulm edema, fluid overload, inhalational injury, ARDS, pulmonary embolism, allergic reaction, near drowning, adverse drug reaction
possible causes of acute hypertension/tachycardia
sympathetic surge pain hypoxia hypercarbia hypovolemia anemia bladder perf if TURP perf of prostatic capsule if TURP TURP syndrome
HTN could lead to MI/cerebral infarction
ddx: acute hypotension, increased peak insp pressures, O2 sat drop
and action steps
migration of ETT into right mainstem tension pneumo cardiac tamponade pulm emoblus (VTE, fat, air, amniotic) allergic reaction aspiration pneumonitis (acute incraese in PVR 2/2 hypoxic pumonary vasoconstriction)
action: hand ventilate, auscultate, 100% FiO2, verify ETT, order CXR, examine chest, consider ABG, PA cath, TEE
ddx - PaO2 68 and FiO2 50%
aspiration pneumonitis cardiogenic pulmonary edema neurogenic pulmonary edema (after injury to central nervous system ARDS TRALI TACO
PCW tracing changes with acute severe mitral regurg
prominent v wave, abolished x decent, rapid y descent
2/2 acute volume overload of the relatively noncompliant left atrium
weaning CPB; increased PA pressure and decreased systemic pressure
LV failure
2/2:
- increased afterload 2/2 MV replacement
- graft failure (kinking, air, clot)
- inadequate myocardial preservation during CPB
- inadequate coronary blood flow (hypotension, coronary emboli, coronary spasm, tachycardia with decreased diastolic perfusion time)
- myocardial infarction
- valve failure
- hypoxemia
- inadequate preload (hypovolemia, loss of atrial kick)
- reperfusion injury
- acidemia
- electrolyte abnormalities
diabetes insipidus vs SIADH
DI:
neurogenic: lack of ADH
nephrogenic insensitivity to ADH
caused by head trauma etc or kidney insult
hypernatremia, mental status changes, high UOP, low urine osmolarity
treat with D51/4NS
neurogenic: vasopressin/desmopressin/chlorpropamide
nephrogenic: HCTZ
SIADH:
excess ADH despite low serum osmolarity
head trauma/tumor, post op, liver dz, adrenal insufficiency
mental status changes, n/v, coma, seizures, headache
hyponatremia, low UOP, high urine osmolarity
treat with NS, fluid restriction, demeclocycline
