Truelearn Flashcards
What causes overdamping of pressure waveform?
factors that increase the compliance of or resistance within the circuit—such as the addition of stopcocks, air bubbles, or distensible tubing
(MAP) is generally preserved
https://d2vrujxrqm3l5p.cloudfront.net/18bb49e1-3d33-4e67-99e9-3162bd98691d.png
What are the indication for hyperbaric oxygen therapy?
Gas-bubble disease (air embolism and decompression sickness)
Carbon monoxide poisoning
Infections (clostridial myonecrosis, other soft tissue necrotizing infections, refractory chronic osteomyelitis, intracranial abscess)
Acute tissue ischemia (crush injury, compromised skin flaps, central retinal artery or vein occlusion)
Chronic ischemia (radiation necrosis, ischemic ulcers)
Acute hypoxia (exceptional blood loss anemia when transfusion is unable to be given)
Acute thermal burn injury
Idiopathic sudden sensorineural hearing loss
Does adding Epi to buvipicaine prolong it’s effect? explain?
No. It improves quality of the analgesia. Epi decreases overall blood loss at site of admin, reducing systemic absorption by decreasing blood flow. This effect is more pronounced with short or intermediate acting local anesthetics.which tend to be more hydrophilic and less preferentially bound to tissue proteins.
By contrast, longer-acting local anesthetics such as bupivacaine exhibit durations of effect that are less responsive to vasoconstrictive additives such as epinephrine.
Indications for prophylactic antibiotics
Only patients who are undergoing dental procedures that “involve the manipulation of gingival tissue…periapical region of teeth, or perforation of the oral mucosa” are to be considered for prophylactic antibiotics
Only patients who are undergoing dental procedures that “involve the manipulation of gingival tissue…periapical region of teeth, or perforation of the oral mucosa” are to be considered for prophylactic antibiotics
Prosthetic cardiac valves, including transcatheter-implanted prosthetic valves
Patients with implanted prosthetic material, such as annuloplasty rings and artificial chordae tendineae
Patients with a history of infectious endocarditis
Patients with a history of unrepaired cyanotic congenital heart disease, including patients with a repair, but with a residual shunt or valvular regurgitation near an implanted patch or device
Patients with a history of cardiac transplantation who have a regurgitant valvular lesion due to a structurally abnormal valve
Most effective anesthetic technique for FIRST stage of labor
lumbar sympathetic block
- L2 and L3. A lumbar sympathetic block interrupts the transmission of pain impulses from the cervix and lower uterine segment to the spinal cord
https://d2vrujxrqm3l5p.cloudfront.net/ca4a1e03-a31a-4080-9312-714cb7ef354e.png
First stage - regular contractions with dilation of cervix <10cm
Second stage - cervix fully dilated >10cm. ends with birth of baby
third stage- placenta
Phosgene toxicity effects
colorless gas, smells like grass. causes significant pulmonary damage. Supportive care is tx. minimize inflammation
Bronchial cuff is clamped on double lumen tube. which lung is down?
Left lung
Bronchial cuff is suppose to be in left main bronchus. Tracheal cuff will close air to right lung
https://d2vrujxrqm3l5p.cloudfront.net/c092f823-b11e-4fbd-827c-31d5d4c8b869.png
What effect describes the hemoglobin oxygen dissociation curve caused by changes in carbon dioxide and pH?
Bohr effect
Chronic acid-base changes over 24-48 hours will alter levels of 2,3-DPG leading to a return to baseline of a shifted oxygen dissociation curve.
What is the Haldane effect?
Describes how oxygen concentrations determine hemoglobin’s affinity for carbon dioxide.
Ex: high oxygen concentrations enhance the unloading of carbon dioxide.
What principle described oxygen consumption relation to cardiac output?
Fick’s principle.relates oxygen consumption to cardiac output and the oxygen content difference between arterial and venous blood.
Ficks principle equation
VO2 (oxygen consumption) = Q (cardiac output) x (arterial -venous)O2
Q = HR \* SV SV = EDV - ESV
a = arterial O2 (left heart)
v = venous O2
difference in these is the oxygen delivered to tissues (which is used in the ETC)
What is the chloride effect?
chloride shift refers to the reaction in which bicarbonate is exchanged for a chloride ion across the red blood cell membrane. Bicarbonate is formed by the reaction of carbon dioxide and water via carbonic anhydrase (carbonic acid is initially formed but readily dissociates into bicarbonate and hydrogen ions).
how is CO2 transported in blood?
Dissolved CO2 in blood 7%
Binds to Hb 23%
covered to Bicarbonate in RBC (via carbonic anhydrase in RBC)
CO2 + H2O – HCO3 + H+
What chemical controls autoregulation of hepatic blood flow?
Adenosine.
Liver blood supply? Most oxygen content?
Hepatic artery 25% of blood flow, 50% oxygen supply
Splanchnic organs (intestines, stomach, pancreas, and spleen) 75% blood flow, 50% oxygen supply
Respritory changes in pregnancy
Decreased
- Residual volume
- Expritory reserve volume
- (FRC = ERV + RV) also decreased
Increased
- Inspritory reserve volume
- Tidal volume
Closing capacity unchanged
Vital capacity = ERV+ IRV + TV unchanged
What causes rightward shift in hemoglobin curve?
What causes leftward shift in hemoglobin curve?
A leftward shift increases hemoglobin’s affinity for oxygen and reduces tissue delivery.
The following factors cause a leftward shift of the P50 of hemoglobin:
• Hypothermia
• Carbon monoxide
• Fetal hemoglobin (Hgb F)
• Methemoglobin
• Hypophosphatemia (seen in the critically ill)
Late decelerations in pregnancy signify
Management of late decelerations in pregnancy, first step and later
Reposition pt in lateral position
IV fluids if hypotensive, leg raise
Discontinue uterotonic drugs
Administer tocolytic if sustained uterine contractions
Pt on low dose SQ Heparin (5000units BID or TID), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
4-6 hours
restart immediatly after
hold 4-6 hours before removing catheter
Pt on HIGH dose SQ Heparin (7500-10,000units BID), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
Hold 12 hours AND normal coagulation status
Avoid restarting if catheter in place
Restart immediatly after catheter removal
Pt on Theraputic dose SQ Heparin (>20,000units), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
Hold for 24 hours AND normal coagulation status
Avoid restarting is catheter in place
Restart immediatly after removal
Pt on IV Heparin, how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
Hold 4-6 hours AND normal coagulation status
Restart 1 hour after procedure
hold 4-6 hours prior to removal of catheter
restart 1 hour after removal
Pt on prophylactic LMWH (daily), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
Hold for 12 hours prior to procedure
restart after 12 hours if catheter in place
Hold 12 hours before removing catheter
restart after 4 hours AND no earlier than 12 hours
after catheter placement
Pt on Therapeutic LMWH, how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?
Hold for 24 hours prior to procedure
Avoid restarting if catheter in place
Restart 4 hours AND no earlier than 24 hours after catheter placement
What is Heliox used for? What is the mechanism?
Used to treat patients with airway obstruction such as that produced by postoperative stridor.
Mixture’s lower density compared to oxygen alone, which increases the flow of gas across obstructed airways.
How to treat stridor
- supplemental or humidified oxygen therapy
- inspired racemic epinephrine
- steroids
- noninvasive positive-pressure ventilation modalities
- helium-oxygen combinations
- Intubation (last resort)
What is Renauds number proportional to?
Re is directly proportional to gas density (ρ), gas velocity (v), and diameter (D)
indirectly proportional to gas viscosity (μ).
Most common cardiac manifestation of Rheumatoid artheritis
Mitral regurgitation is the most common
Aortic valve disease, especially aortic regurgitation, is also often seen. Stenotic valve lesions are not typically associated with RA.
Electrolyte abnormality associated with hyperventilation (respiratory alkalosis)?
Hypocalcemia.
In response to alkalosis, hydrogen ions bound to negatively charged plasma proteins, such as albumin, are released. Calcium, being positively charged, can then bind to albumin and other proteins, thereby decreasing the serum calcium concentration (particularly the free/ionized, active fraction). This is the mechanism behind paresthesias that occur with hyperventilation.
Hypokalemia.
Hydrogen-potassium transporters pump hydrogen ions out of cells in the setting of alkalosis to restore physiologic pH. Simultaneously, potassium is pumped intracellularly to ensure electroneutrality.
Alkalosis can cause hypophosphatemia.
A rising cellular pH stimulates the glycolytic pathway, enhancing sugar-phosphate production. This triggers increased cellular uptake of phosphorus, thus decreasing serum phosphorus concentration.
Management of Von Willebrand disease in pregnant women undergoing c-section. Which clotting factor is deficient?
Indication for treatment?
von Willebrand factor serves as a carrier protein for factor VIII
von Willebrand disease (vWD) who have a factor VIII level >50% do not require treatment during labor or cesarean delivery. During pregnancy, there is an increase in the levels of factor VIII and von Willebrand factor (vWF) that normally corrects the deficiency seen in type 1.
Desmopressin when factor VIII levels are < 50%
If pt doesnt respond, Humate-P or Alphanate can be used, which is a concentrate of factor VIII and vWF.
If actor VIII is < 50%, desmopressin should be administered for type 1, and factor VIII and vWF concentrates should be administered for types 2 and 3.
IgA deficiency requiring transfusion, which type of transfusion is appropriate to minimize risk of anaphylaxis
Washed.
preparation involves washing the RBCs to remove donor plasma until IgA levels are reduced < 0.05 mg/dL
Mechanism of hypoxic pulmonary vasoconstriction (HPV) during OLV
Affect of NO and volatile anesthetics on hypoxic pulmonary vasoconstriction during OLV
Inhibits HPV
Presentation of congenital diaphragmatic hernia, initial management
In addition to nonspecific features of neonatal respiratory failure including retractions, grunting, nasal flaring, and tachypnea, CDH may present with a barrel-shaped chest, a scaphoid or sunken abdomen, unilateral breath sounds, and displacement of the heartbeat due to visceral displacement and mediastinal shift.
ETT, deliver low tidal volumes, low peak inspiratory pressures, permissive hypercapnia, and minimal supplemental oxygen to avoid further injury to the hypoplastic lung.
(PPV with mask/t piece is contraindicated due to risk of risk of forcing air into the stomach or loops of herniated bowel within the thorax.