Critical care: anaesthesiology, blood gases & respiratory care Flashcards
75yo thin cachectic woman undergoes a trachoestomy for failure to wean from the ventilator. 1w later, she develops significant bleeding from the tracheostomy. which of the following would be an appropriate initial step in the management of this problem?
a. remove the tracheostomy and place pressure over the wound
b. deflate the balloon cuff on tracheostomy
c. attempt to reintubate the pt with an endotracheal tube
d. upsize the tracheostomy
e. perform fiberoptic evaluation immediately
C
= sentinel bleed from trachoinominate artery fistula = >50% mortality
bleeding has stopped = immediate fiberoptic exploration
bleeding continuing = (stopgap measures)
1) inflate tracheostomy balloon to compress innominate artery
2) reintubate pt with endotracheal tube
3) remove tracheostomy & place figer through site with anterior compression of innominate artery
- -> 4) median sternotomy in OR
53 yo woman has been intubated for several days after sustaining a R pulmonary contusion after a motor vehicle collision as well as multiple rib fractures. which of the following is a reasonable indication to attempt extubation?
a. negative inspiratory force (NIF) of -15cm HxO
b. PO2 of 60mmHg while breathing 30% inspired FiO2 with a positive end-expiratory pressure (PEERP) of 10cm H2O
c. spontaneous respiratory rate of 35 breaths per minute
d. rapid shallow breathing index of 80
e. minute ventilation of 18L/min
D
b - too low of PO2
c. - will fatigue
e - 18L/min too high of O2 requirement
Predictors of successful extubation
- rapid shallow breathing index = ratio of RR / tidal volume = 60-105
- negative expiratory force > -20
- PEEP = 5cm H2O
- Minute ventilation < 10L/min
- Spontaneous RR < 20.
19yo man receives an un cross-matched blood during resuscitation after a gunshot wound to the abdomen. he develops fever, tachycardia, and oliguria during teh transfusion and is diagnosed as having a hemolytic rxn. which of the following is the most appropriate next step in management of this pt?
a. administration of a loop diuretic such as furosemide
b. treating anuria with fluid and pottassium replacement.
c. acidifying the urine to prevent Hgb precipitation in the renal tubules
d. removing foreign bodies, such as Foley catheters, which may cause hemorrhagic complication
e. stopping the transfusion immediately.
E
1) stop transfusion
2) Foley = d/t precipitation of hemoglobin in renal tubules
3) Na-bicarbonate = alkalinize urine to prevent Hgb precipitation
4) mannitol = stimulate diuresis
5) Restrict fluid, K
74yo woman with a hx of a previous total abdominal hysterectomy presents with abdominal pain and distension for 3d. she is noted on her plain films to have dilated small bowel and air fluid levels. she is taken to the operating room for SBO. which of the following inhalational anaesthetics should be avoided b/c of accumulation in air-filled cavities during general anaesthesia.
a. biethyl ether
b. nitrous oxide
c. halothane
d. methoxyflurane
e. tricholoroethylene
B
Nitrous oxide = lower solubility v. other anaesthetics (more soluble v. nitrogen - the form that diffuses out of gass filled compartments) –> can cause progressive distension of air-fluid spaces during prolonged anaesthesia by diffusing into gas-filled compartment
–> worsened distension (ex. SBO)
61yo alcoholic man presents with severe epigastric pain radiating to his back. his amylase and lipase are elevated, and his diagnosed with acute pancreatitis. over the first 48h, he is determined to have 6 Rnason’s criteria, including a PAO2 < 60. his chest xray reveals b/l pulmonary infiltrates, and his wedge pressure is low. which of the following criteria must be met to make a diagnosis of ARDS.
a. hypoxemia defined as PaO2/FiO2 ratio of <200
b. hypoxemia defined as a PaO2 of <60
c. pulmonary capillary wedge pressure >18
d. lack of improvement in oxygenation with administration of a test dose of furosemide
e. presence of a focal infiltrate on CXR
A
if C - cardiac problem. so CAN’T be elevated
if d - crue but not a criteria
criteria for ARDS
1) hypoxemia unresponsive to elevation of inspired O2 conc.
2) decreased pulmonary compliance = lungs stiffer & harder to ventilate
3) decreased functional residual capacity
= leakage of protein-rich fluid into interstitium & alveoli from non-cardiogenic cause = “diffuse fluffy infiltrates b/l”
===> shunt formation, decreased resting lung volume, increased dead-space ventilation
50yo man has respiratory failure due to pneumonia and sepsis after undergoing splenectomy for a traumatic injury. which of the following management strategies will improve tissue O2 uptake (i.e. shifting the O2 dissociation curve).
a. transfusion of banked blood to correct acute anemia.
b. correction of acute anemia with erythropoetic stimulating agent
c. administration of bicarbonate to promote metabolic alkalosis
d hypoventilation to increase the PaCO2
e. administration of an antipyretic to lower the pt’s temp.
D
SHIFT TO THE RIGHT = O2 dropped off to tissues = tissue O2 uptake
PaCO2
H+
Temp
SHIFT TO THE LEFT = O2 retained by Hgb (like myoglobin)
Myoglobin
64yo man with hx of severe emphysema is admitted for hematemesis. the bleeding ceases soon after admission, but the pt becomes confused and agitated. arterial blood gases are as follows. pH 7.23, PO2 42; PCo2 75. which of the following is the best initial therapy for this pt?
a. correct hypoxemia with high flow nasal O2
b. correct acidosis with sodium bicarbonate
c. administer 10mg IV dexamethasone
d. administer 2mg IV ativan
e. intubate the pt
E
respiratory acidosis - low RR.
speed up RR
- endotracheal intubation
- ventilatory support
signs of hypoxemia
- agitation
- confusion
62yo woman with a hx of coronary artery disease presents with a pancreatic head tumor & undergoes a pancreaticoduodenectomy. postop, she develops a leak from the pancreaticojejunostomy anastamosis and becomes septic. a swan-ganz catheter is placed, which demonstrates an increased cardiac output and decreased systemic vascular resistance. she also develops acute renal failure and oliguria. which of the following is an indication to start dopamine?
a. to increase splanchnic flow
b. to increase coronary flow
c. to decrease heart rate
d. to lower peripheral vascular resistance
e. to inhibit catecholamine relese.
B
septic shock
Dopamine
- increased diastolic BP
- coronary blood flow
(low dose) - directed blood flow to kidneys & bowel (vasodilation of renal & mesenteric BV, mild vasoconstriction of peripheral bed
(high dose) - B1 receptor activity - increased CO & BP
(highest dose) - alpha activity = peripheral vasoconstriction, shifting of blood from extremities to organs, decreased kidney fx, HTN
29yo woman on oral contraceptives presents with abd pain. a CT scan of the abdomen demonstrates a large hematoma of the R liver with the suggestion of an underlying liver lesion. her Hgb is 6, and she is transfused 2units of pRBCs and 2U of fresh frozen plasma. 2h after starting the transfusion, she develops respiratory distress and requires intubation. she is not volume overloaded clinically, but her CXR shows b/l pulmonary infiltrates. which oft the following is the management strategy of choice?
a. continue the transfusion and administer an antihistamine
b. stop the transfusion and administer a diureticc. stop the transfusion, perform bronchoscopy, and start broad-spectrum empiric antibiotics
d. stop the transfusion and continue supportive respiratory care
e. stop the transfusion and send a coomb’s test
D
TRALI = transfuion related acute lung injury
- sxs = respiratory distress, hypoxemia, b/l pulmonary infiltrates (non-cardiogenic)
Tx (overall) = mechanical ventilation
Complications
1) allergic rxn –> antihistamine
2) transfusion-associated circulation overload (pts with heart failure) –> diuretics
3) hemolytic rxn = dx: positive coombs test –> stop transfusion; identify responsible antigen
68yo hypertensive man undergoes successsful repair of a ruptured abdominal aortic aneurysm. he receives 9L ringer lactate solution a nd 4U of whole blood during the operation. 2h after transfer to the surgical ICU, the following hemodynamic parameters are obtained: systemic BP 90/60, pulse 110, CV 7mmHg, pulmonary artery wedge pressure (PCWP) 8, cardiac output 1.9, SVR 1400 (nml = 900-1300), PaO2 140, urine output 15 (specific gravity: 1.029), and Hct 35% . given this data, which of the following is the most appropriate next step in management?
a. administration of a diuretic to increase Urine output
b. administration of a vasopressor agent to increase systemic BP
c. administration of a fluid challenge to increase urine output
d. administration of a vasodilating agent to decrease elevated SVR
e. a period of observation to obtain more data.
C. rapid fluid infusion; expansion of IV volume (lactated ringers, blood).
b/c very hypotensive, likely from blood loss
NOT vasopressor - increases PVR & BP, decreased tissue perfusion
NOT vasodilation = decreased PVR –> HYPOTENSION; vascular collapse
NOT diuretic –> increased volume depletion
59yo man with a hx of MI 2y ago undergoes an uneventful aortofemoral bypass graft for aortoiliac occlusive disease. 6h later, he develops ST segment depression, and a 12-lead EKG shows anterolateral ischemia. his hemodynamic parameters: systemic BP70/40, pulse 100, CVP 18, PCWP 25, cardiac output 1.5L/min, and SVR 1000. which of the following is the single best pharmacologic intervention for this pt?
a. sublingual nitroglycerin
b. IV nitroglycerin
c. a short-acting B-blocker
d. sodium nitroprusside
e. dobutamine
E
increased LA pressure
low cardiac output
–> cardiogenic shock - MI from bypass
NOT
options:
1) Dobutamine (B1) = inotropic; mildly increased peripheral vasodilation (chronotropy)
- increased CO + stable myocardial O2 demand on an already failing heart.
2) Nitroglycerin/nitroprusside + ionotrope = relax heart, and maintain BP
B blocker = decreased cardiac contractility & HR
56yo an undergoes a L upper lobectomy. an epidural catheter is inserted for postoperative pain relief. 90 min after the first dose of epidural morphine, the pt complains of itching and becomes increasingly somnolent . blood gas measurement reveals the following pH 7.24, PaCO2 58, PaO2 100, and HCO3- 28. which of the following is the most appropriate initial therapy for this pt?
a. endotracheal intubation
b. intramuscular diphenhydramine (Benadryl)
c. epidural naloxone
d. IV naloxone
e. alternative analgesia.
D
likely liver lobectomy - being given an epidural with dilaudid
allergic to morphine
respiratory acidosis = due to depressed respiratory drive.
reverse the opiate
71yo man returns from the OR after undergoing a triple coronary bypass. his initial cardiac index is 2.8L/min-m2. HR is then noted to be 55 BPM, BP is 110/80, wedge pressure is 15, and his cardiac index has dropped to 1.6L/min-m2. he has a normal LV. which of the following maneuvers will increase his cardiac output.?
a. increase his PVR
b. increase his CVP
c. increase his HR to 90 by electrical pacing
d. increase his blood viscosity
e. increase his inspired O2 concentration
C
poor cardiac output (due to low preload)- not necessarily cardiogenic shock.
a - only for BP
cardiac index = cardiac output / body surface area
CI = CO/BSA
= (SV*HR)/BSA
73yo woman with a long hx of heavy smoking undergoes femoral artery-popliteal bypass for rest pain in her L leg. b/c of serious underlying respiratory insufficiency, she continues to require ventilatory support for 4d after her operation. as soon as her endotracheal tube is removed, she begins complaining of vague upper abd pain. she has daily fever spikes of 39C (102.2 F) and a leukocyte count of 18,000. an upper abd ultrasonogram reveals a dilated gallbladder, but no stones are seen. a presumptive diagnosis of acalculous cholecystitis is made. which of the following is the next best step in her treatmt?
a. nasogastric suction and broad-spectrum abx
b. immediate cholecystectomy with operative cholangiogram
c. percutaneous drainage of the gallbladder
d. endoscopic retrograde cholangiopancreatography (ERCP) to visualize and drain the CBD.
e. provocation of cholecystokinin release by cautious feeding of the pt
C. Acute postoperative cholecystitis
= thickened gallbladder, pericholecystic fluid; nonvisualization of gallbladder on HIDA (=no taking up fluid b/c blocked).
==> potential fatal complication
no stone to take out.
tx = percutaneous drainage + Abx
ascending cholangitis -> charcot’s triad = fever, abd pain, jaundice.
reynold’s pentad = charcot’s + MS changes + hypotension.
32 yo man undergoes a distal panreatectomy, splenectomy, and partial colectomy for a gunshot wound to the L upper quadrant of the abdomen. 1wk later, he develops a shaking chill in conjunction with a temp spike of 39.4C (103F). his BP is 70/40, pulse 140, and RR 45. he is transferred to the ICU, where he is intubated and a swan-ganz catheter is placed. which of the following is consistent with the expected initial swan-gantz catheter readings.
a. increase in CO
b. increase in PVR
c. increase in pulmonary artery pressure
d. increase in PCWP
e. increase in CVP
A- to compensate for decreased peripheral vascular resistance
sepsis = SIRS + bacterial source
- decreased PVR
- normal central pressure
- increased CO
Tx
- resuscitation = fluid replacement, vasopressor
- stabilization = Abx for GNR, anaerobes (intra-abdominal)
- laparotomy, drainage of colleciton
likely sub-diaphragmatic abscess - common complication post-splenectomy
43yo trauma pt develops ARDS and has difficulty oxygenating despite increased concentrations of inspired O2. after the PEEP is increased, the pt’s oxygenation improved. what is the mechanism by which this occurs?
a. decreasing dead-space ventilation
b. decreasing the minute ventilation requirement
c. increasing tidal volume.
d. increasing functional residual capacity
e. redistribution of lung water from the interstitial to the alveolar space
D
PEEP= keeps alveoli openat end of expiration
- INCREASED FUNCTIONAL RESIDUAL CAPACITY
- increase surface area for diffusive exchnage of gases
complications
- overdistension = barotrauma; pneumothorax
- decreased VR, CO
- increased dead space ventilation = increased ventilation requirements
27yo man was assaulted and stabbed on the L side of the chest between the areola and sternum. he is hemodynamically unstable with jugular venous distension, distant heart sounds, and hypotension. which of the following findings would be consistent with a diagnosis of hemodynamically significant cardiac tamponade
a. more than a 10mmHg decrease in systolic BP at the end of the expiratory phase of respiration
b. decrease RA pressures on swan-ganz monitoring
c. equalization of pressures across the 4 chambers on the swan-ganz monitoring
d. compression of the LV on echocardiography
e. overfilling of the RA
C
increased pressures, soft heart sounds
- Beck triad = systemic hypotension, jugular venous distension, distant heart sounds
- pulses paradoxus = decrease in SBP by >10mmHg at end of inspiratory phase of respiration
- ECHO = pericardial fluid & RA collapse
- Swan Ganz = Equalization of pressures across the 4 chambers
- decreased RA pressure; decreased CO; increased CVP
55yo woman requires an abdominoperineal operation for rectal cancer. she has a hx of stable angina. which of the following clinical markers is most likely to predict a cardiac event during her noncardiac surgery and should prompt further cardiac workup prior to her operation?
a. abnormal EKG
b. prior stroke
c. unstable angina
d. uncontrolled HTN
e. her age.
C
–> because can lead to MI
MAJOR predictors of cardiac event during noncardiac surgery
- unstable angina
- recent MI
- decompensated CHF
- significant arrhythmia
- severe valvular disease
MED predictors
- mild angina
- prior MI
- compensated / prior CHF
- DM
- renal insufficiency
MINOR predictors
- older age, abn EKG, irregular rhythm,
- poor functional capacity
- prior stroke
- uncontrolled HTN
a 22yo man sustains severe blunt trauma to the back. he notes that he cannot move his LE. he is hypotensive and bradycardic. which of the following is the best inital management of the pt?
a. digital block with 1% lidocaine without epinephrine up to 4.5mg/kg
b. digital block with 1% lidocaine with epinephrine up to 4.5mg/kg
c. digital block with 1% lidocaine with epinephrine up to 7mg/kg
d. local injection around the nail bed with 1% lidocaine without epinephrine up to 4.5mg/kg
e. local injection around the nail bed with 1% lidocaine without epinephrine up to 7mg/kg
A
digital block = at side of the nail bed of the specific digit.
inject with lidocaine for local anaesthesia & epinephrine to decrease bleeding.
For a normal sized person (70kg) = 4.5mg/kg of lidocaine.
where NOT to use epinephrine
- tissues supposed by end arteries
- ex. fingers, toes, ears, nose, penis
22yo man sustains severe blunt trauma to the back. he notes that he cannot move his LE. he is hypotensive and bradycardic. which of the following is the best initial management of the pt?
a. administration of phenylephrine
b. administration of dopamine
c. administration of epinephrine
d. IV fluid bolus
e. placement of a transcutaneous pacer
D
Neurogenic shock due to spinal cord injury –> loss of sympathetic tone; bradycardia; loss of reflexive increase in HR
Tx = fluids + vasoconstrictors (dopamine, phenylephrine)
If bleeding –> hypovolemic shock
58 yo woman with multiple comobidities and previous cardiac surgery is in a high speed motor vehicle collision. she is intubated for airway protection. b/c of hemodynamic instability. a central venous catheter is placed in the R subclavian vein. while the surgeon is securing the catheter, the cap becomes displaced and air enters the catheter. suddenly, the pt becomes tachycardic and hypotensive. which of the following is the best next maneuver.
a. decompression of the R chest with a needle int he 2nd intercostal space.
b. placement of a R chest tube.
c. withdrawal of the central venous catheter several cm.
d. placement of a pt is a L lateral decubitus trendelenburg position
e. b/l “clamshell” thoracotomy with aortic cross-clamping
D
= air embolism into heart.
don’t clamp the aorta.
Tx
1) place into L lateral decubitus trendelenburg
2) aspirate central venosu catheter
3) LATER - thoracotomy
Tension pneumo = decompression of R chest with needle / chest tbe
Arrhythmia = withdrawal of central venous catheter