Principles of Anesthesia Practice I Unit II Flashcards
How should joints be aligned?
In as natural a position as possible, pressure points should be padded
What safety measures must be used in the abdominal/pelvic area?
Safety belts/straps, take care to avoid placing them too tightly
What is the timeframe for nerve injury to occur?
Short, it does not take long for injury or irreversible damage to occur
can occur in as little as 30 minutes
What is the most common surgical position?
Supine
What are the pathophysiology considerations of the supine position?
Increased venous return, preload, SV and CO, decrease in Vt and FRC
Describe the correct positioning of arm abduction
Out to the side less than 90 degrees, padded arm boards, arms should be supine (palms up) elbows padded and arm secured with a strap
Describe the correct positioning of arm adduction
Tucked alongside the body, arms held alongside the body with a draw sheet, hands/forearm are supine (palms up) or neutral (palms towards body), elbows are padded, may tuck one arm if surgeon must stand on side of patient
Complications of supine?
Backache, Pressure alopecia, Brachial plexus or axillary nerve injury if arms abducted > 90 degrees, Ulnar nerve injury if hand/arm is pronated (palm down), Stretch injury when neck is extended and head turned away (brachial plexus)
What methods can you use to help prevent a patient in trendelenburg from sliding?
Use a non-sliding mattress/pad, use a mark on the sheet to measure movement, avoid bean bags
Pathophysiology of trendelenburg?
Increase: CO (more venous return), ICP/IOP (edema of face, conjunctiva, larynx and tongue a concern) and intra-abdominal pressure
Decrease: FRC and pulmonary compliance and diaphragm shifts up
May need higher ventilation pressures and risk of endobronchial intubation as abdominal contents push the carina cephalad
What methods can you use to help prevent a patient in reverse trendelenburg from sliding?
Use of non-sliding mattress/pad, use of a footrest
Pathophysiology of reverse trendelenburg?
Hypotension risk (blood pools in the lower extremities), downward displacement of abdominal contents and diaphragm, decreased perfusion to the brain
What steps must be taken to secure a patient in the sitting position?
Stabilize the head (head rest or pins), hips are flexed less than 90 degrees with knees slightly flexed, feet are supported to prevent sliding, compression stockings to maintain venous return, keep at least 2 fingers distance between chin and sternum
Why is beach chair position used frequently in shoulder cases?
Less severe hip flexion and slight leg flexion
Risks of the sitting position?
Cerebral hypo-perfusion and air embolism, Pneumocephalus, Quadriplegia and spinal cord infarction, Cerebral ischemia, Peripheral nerve injuries (big one is sciatic nerve injury)
Pathophysiology considerations of sitting position?
Hypotension risk (venous pooling), decreased MAP/CI and cerebral perfusion pressure
Describe what is entailed in supporting/placing a patient in the prone position
Arms are tucked or stretched less than 90 degrees with elbow flexion, head is supported face down with a pillow/headrest/rigid fixation with care taken to minimize pressure on eyes/nose/mouth/ears, avoid compression of breasts/abdomen/genitalia, legs padded and slightly flexed at the knees/hips, stockings to prevent venous pooling.
intubate supine then prone the patient, EKG leads go on the back
What are the risks of prone positioning?
Facial and airway edema, nerve injuries, post-op visual loss d/t ischemia, ET tube dislodgement, loss of monitor and/or IV lines
What causes ulnar nerve injury in prone positioning? Brachial plexus injury?
Ulnar = if elbows are not padded
Brachial = if arms are abducted greater than 90 degrees
Prone pathophysiology considerations?
Edema of face, conjunctiva, larynx, and tongue, increased abdominal pressure (this reduces venous return from the inferior vena cava which reduces CO), improved ventilation (ventilation and perfusion shifts to the dependent areas of the lung)
Describe lithotomy position
Patient is supine with legs up in padded or candy cane stirrups, arms tucked or on arm boards, if either trendelenburg is needed use a non-slide mattress, hips flexed 80 - 100 degrees and legs abducted 30-45 degrees from midline with knees flexed, lower extremities must be raised/lowered in synchrony (this prevents torsion to the lumbar spine), ensure fingers/hands are free of the foot of the bed when lowered, with longer surgeries try to periodically lower the legs
Lithotomy pathophysiology considerations?
Increased venous return/CO and ICP, increased intraabdominal pressure (diaphragm moves up), decreased lung compliance and Vt
Describe lateral decubitus position
Lies on the non-operative side (dependent) requiring anterior/posterior support with rolls/bean bags, adequate head support (ensure neutral position, check dependent ear regularly), dependent leg is slightly flexed, arms are in front and must be supported and abducted less than 90 degrees, axillary role placed between the chest wall and bed caudal to the axilla (prevention of brachial plexus injury) and pad between the knees
What side of the patient is down in right lateral decubitus?
Right side is down (dependent)
In lateral decubitus, what must be done if the bed is flexed?
You must use a kidney rest, or place the point of the bed under the iliac crest (this prevents inferior vena cava compression and allows for lung expansion of the dependent lung)
Watch carefully for ET tube dislodgement, caution the use of an LMA
Lateral decubitus pathophysiology concerns?
Venous pooling, V/Q mismatch (inadequate ventilation to the dependent lung and decreased blood flow to the non-dependent lung, think back to his Schmidtness and those concepts)
What is the basic MOA of most nerve injuries?
A result of stretch, pressure or ischemia though the exact MOA is unclear
What is the basic timeframe for nerve injuries to occur?
In as little as 30 minutes
What type of nerve is most commonly injured?
Sensory, though it may be combined sensory and motor, it may also be temporary or permanent
T/F: nerve injuries can occur with optimal positioning
True
What changes can alter waters ability to auto-ionize?
Changes in relative concentrations of fluids and e-lytes
this ensures optimal enzymatic function
Who noted the loss of carbonate of soda in cholera patients?
O’Shaughnessy in 1831
What are the definitions of acidemia and alkalemia?
Acidemia = Excess production of H+ (in relation to hydroxyl ions)
Alkalemia = Excess production of OH- (in relation to hydrogen ions)
What exactly is measured on the pH scale?
The hydrogen ion concentration
What are the 3 primary substances the body manipulates to manage pH?
CO2 entering/leaving via the lungs
HCO3 enter/leaving via the kidneys (in the PT)
H+ being reabsorbed in the distal tubule and the collecting duct
Write out the henderson-Hasselbalch equation
pH = 6.1 + log (serum bicarb / 0.03 x PaCO2)
What is the definition of a substance that can either donate or receive a proton depending on the other substrate? What is an example of this in the body?
Amphoteric, and water is the classic example of this
In the presence of HCl (strong acid) it donate a proton to water (a base in this scenario)
In the presence of KOH (a strong base) it receives a proton from water (an acid in this scenario)
What is the relationship of pKa (or strength of the acid) to the degree of dissociation in water?
In general, strong acids have a lower pKa (lactic acid has a pKa of 3.4) completely dissociate compared to a weak acid like carbonic acid which has a pKa of 6.4 and only partially dissociates
What 3 rules govern the body and its behavior in regards to ions and pH management?
The body wants to remain electrically neutral, the dissociation equilibria and mass of conservation
What are the most abundant ECF strong ions? The others?
Most common = Na+ and Cl -
Others = K+, SO42-, Mg2+, Ca2+
Describe the strong ion difference equation
Total strong cations - strong anions
Is SID + or - in the ECF? How can it be used in clinical pH management?
In the ECF, SID is always positive (meaning there will be more cations than anions in the ECF). SID is an independent predictor of pH
remember, a cell tends to be more negative, and will have more anions, this needs to be balanced out by a more + ECF
For THIS class, if PaCO2 and HCO3 change in the same or opposite directions, what is the acid/base disorder?
Same direction = primary disorder with secondary compensation
Different direction = mixed acid/base disorder
Identify this acid/base disorder: pH 7.33, PCO2 48, HCO3 26
Respiratory acidosis, body is attempting to compensate
Identify this acid/base disorder: pH 7.58, PCO2 35, HCO3 29
Metabolic alkalosis
Identify this acid/base disorder: pH 7.28, PCO2 46, HCO3 18
Mixed acid/base disorder
Identify this acid/base disorder: pH 7.48, PCO2 32, HCO3 22
Respiratory alkalosis
For this class, what is a normal pH, PCO2 and HCO3 (not the range, the “middle of the road number”)?
pH = 7.4
CO2 = 40
HCO3 = 24
What are some CV consequences of acidosis (include the pH level these changes occur if applicable)?
Impaired contractility (at a pH of 7.2), decreased arterial pressure, sensitive to re-entry dysrhythmias, decreased threshold for v-fib and decreased responsiveness to catecholamines (at a pH of 7.1)
think back to ICU days, this is why you can throw boatloads of pressors at acidotic patients and their BP still sucks, their low pH doesn’t allow the catecholamines to work because they denature in the acidic environment
CNS consequences of acidosis?
Obtundation and coma
Pulmonary consequences of acidosis?
Hyperventilation, dyspnea and respiratory muscle fatigue
What is the definition of respiratory acidosis?
An acute decrease in alveolar ventilation results in increased PaCO2
this definition usually requires that pH drop below 7.35 and is indicative of some measure of respiratory failure
What are the 3 categories of respiratory acidosis?
Central ventilation control issues, peripheral ventilation control issues and VQ mismatch
What are some examples of central ventilation control issues?
Drug-induced ventilatory depression, permissive hypercapnia
think drug related, like excess opioids or propofol
What are some examples of peripheral ventilation control issues?
Neuromuscular blockade related to a high epidural/spinal, pneumo/hemothorax
What are some VQ mismatch causes?
Abdominal splinting, retained secretions, atelectasis
What are some obstructed breathing issues that can cause acute respiratory acidosis?
Obstruction of: supraglottic, glottic, subglottic airway. Bronchospasm can also cause it.
What is the difference in the rate of bicarb change in acute vs chronic hypercarbia?
Acute = a 10:1 ratio (for every increase in 10 of PaCO2, bicarb goes up by 1)
Chronic = a 10:3 ratio (for every increase in 10 of PaCO2, bicarb goes up by 3)
If your PaCO2 is 80 mmHg, what is the expected HCO3 level for acute vs chronic hypercarbia?
Acute = 28 mEq/L
Chronic = 36 mEq/L
Why is using bicarb to reverse chronic hypercarbia potentially dangerous?
The excess bicarb causes CNS irritability which increases seizure risk
What are some causes of metabolic acidosis?
Increased production of acid, decreased excretion of acid, acid ingestion or Renal/Gi bicarb losses
It can also be associated with alterations in transcellular ion pumps, increase in iCal and a right shift of the OxyHgb curve
What formula allows you to determine if your current level of bicarb is adequate for your current PaCO2?
1.5 x HCO3 +8
If your bicarb is 12, what level of CO2 can you adequately buffer?
1.5 x 12 + 8 = 26
If your bicarb level is 31, what level of CO2 can you adequately buffer?
1.5 x 31 + 8 = 54.5
What is the ratio of change in base excess to change in partial pressure of CO2 in acute metabolic acidosis?
1:1.2 change, for every decrease of 1 in the base excess, PaCO2 should drop by 1.2 mmHg
Bicarb loss being countered by the net gain of chloride ions is what kind of acidosis?
Hyperchloremic metabolic acidosis
Electrical neutrality is maintained by what 3 ions in the simple anion gap equation?
Na, bicarb and chloride
alterations can occur from NaCl infusions, diarrhea and early renal failure
What is the simple anion gap and conventional anion gap equations?
Simple: Na+ - (Cl- + HCO3-) = 12-14 mEq/L
Conventional: (Na+ + K+) - (Cl- + HCO3-) = 14-18 mEq/L
What are the normal ECF Na, K, Cl and HCO3 levels (these are important for anion gap equations)?
Na = 140, Cl = 105, Bicarb = 24, K = 4
What is the limitation of anion gap equations in estimating electrical neutrality/the level of acidosis?
They generally underestimate the disturbance because they don’t take into account other electrically active compounds (albumin, phosphates) and if you have hypoalbuminemia or hypophosphatemia, then the disturbance is greater than what the anion gap equation predicts
What causes a high anion gap?
Excess acid in the ECF, can be caused by lactic acidosis, ketoacidosis, renal failure or poison
remember, acids dissociate into H+, H+ then combines with bicarb to make carbonic acid which then dissociates into H2O and CO2, this process depletes your bicarb reserves
What is the mnemonic for anion gap acidosis causes?
CATMUDPILES - I’m too lazy to type all this out, here’s the picture
Lactic acidosis is generally a marker of critical illness, such as a mix of over production vs inadequate clearance or persistent acidosis. What process contributes to an excess lactic acid production?
Degradation products of glucose metabolism from substances like catecholamines, lactate to pyruvate and gluconeogenesis. This can also contribute to moving from aerobic to anaerobic metabolism further worsening the lactic acidosis
What SVO2, CVP and SV levels indicate type A vs type B lactic acidosis?
Type A: SVO2 less than 70%, CVP less than 5, SV less than 0.7 ml/kg
Type B: SVO2 greater than 70%, CVP greater than 5, SV greater than 0.7 ml/kg
For type A, think fluid, early infection or cardiac failure. For type B, think poison, liver failure, late stage sepsis, arterial thrombosis or abdominal ischemia of some sort
For type A lactic acidosis, what should you suspect if the Hgb is low?
Likely hemorrhagic shock
For type A lactic acidosis with a normal Hgb, what should you suspect if the CRP/WBCs are high? If CRP/WBCs are normal?
Normal = consider cardiogenic shock (start inotropes, IABP or pericardial drain)
High = likely sepsis, check for a UTI, or intra-abdominal source. Do they have a long-term catheter of some sort?
For type B lactic acidosis, what are some common causes of poisoning?
Metformin, sodium nitroprusside, cyanide and carbon monoxide
For type B lactic acidosis, what should be on your differential diagnosis list if all pulses are intact? If they are not?
Intact = Consider bowel or splanchnic ischemia (get some imaging, prep for ex-lap or bowel resection)
Not intact = consider arterial thrombosis, prep for angiography and revascularization
What lab values indicate lactic acidosis?
Lactate greater than 3 mEq/L and pH less than 7.35
if this occurs, per the decision tree, check an SVO2, CVP and SV
Treatment of ketoacidosis vs lactic acidosis?
KA = insulin and fluids
LA = depends on the cause, in general, improve tissue perfusion, fluid resuscitate and DC metformin. If renal failure is a component, dialyze
Why is treatment of acidosis with bicarb controversial?
Because giving bicarb (think back to Schmidt acid/base lectures) feeds into the carbonic anhydrase equilibrium reaction, increasing bicarb on one side shifts the equation to favor formation of CO2 which can worsen the acidosis in the long run
Why is bicarb administration dangerous in chronic metabolic acidosis?
Acute pH changes negates the right shift (decreased oxygen affinity), so Hgb holds onto oxygen more tightly, meaning less is dropped for acidotic tissue which is likely oxygen starved in acidosis = tissue hypoxia
What is the formula to determine how much bicarb to give?
0.3 x base deficit (mmol/L) x weight in Kg and divide this by 2
the other way to think of this, 0.3 x base deficit (mmol/L) x weight in Kg, once that dose is determined, cut it in half. Both ways get you the same thing, just a mildly different way to approach it
Anesthesia management of lactic acidosis?
Likely postpone surgery, if it is urgent/emergent, get as much hemodynamic monitoring in place as you can, give fluids, monitor cardiac function and get an iStat to frequently monitor labs
What is the definition of respiratory alkalosis?
Acute increased alveolar ventilation that decreases PaCO2, pH is generally greater than 7.45
Respiratory alkalosis causes?
Pregnancy, high altitude, iatrogenic hyperventilation, salicylate overdose
S/sx of respiratory alkalosis?
Lightheadedness, visual disturbances, dizziness - all are caused by vasoconstriction
remember, this vasoconstriction occurs because if you are hypocarbic, the body generally responds with vasoconstriction because it thinks the tissues need less blood flow because there are less metabolic byproducts
Why does hypocalcemia occur in respiratory alkalosis?
There is greater binding of calcium to albumin
S/sx of hypocalcemia?
Paresthesia, muscle spasm, cramps, tetany, circumoral numbness, seizures
Trousseau’s sign (carpo-pedal spasm)
Chvostek’s sign (facial muscle twitch/spasm)
Anesthesia management of respiratory alkalosis?
It’s generally a consequence of pain, anxiety, full bladder or agitation (try to manage them), make sure you don’t have poor mechanical ventilation strategy. Therapeutic hyperventilation can also cause this.
What is the definition of metabolic alkalosis?
Marked increase in plasma bicarb usually compensated for by an increase in carbon dioxide
What are the physiologic processes that can contribute to metabolic alkalosis?
Renal or extrarenal causes, net loss of H or net gain of bicarb (very common if you are on diuretics), excess citrate
also called volume depletion or volume overload alkalosis
Common causes of metabolic alkalosis? S/sx?
Hypovolemia, Vomiting, NG suction, Diuretic therapy, Bicarb administration and Hyperaldosteronism
S/sx = lightheadedness, tetany and paresthesia
Treatment of metabolic alkalosis?
Depends on the cause:
Volume depletion: saline fluid resuscitation
Gastric loss: PPI’s
Loop diuretics: add K+ sparing diuretics
Determine pH: PaCO2 of 64, HCO3 of 39 (round to 3 decimal places)
7.408
Determine pH: PaCO2 of 31, HCO3 of 32 (round to 3 decimal places)
7.627
Determine pH: PaCO2 of 87, HCO3 of 38 (round to 3 decimal places)
7.263
Determine pH: PaCO2 of 49, HCO3 of 22 (round to 3 decimal places)
7.275
Determine pH: PaCO2 of 46, HCO3 of 29 (round to 3 decimal places)
7.423
As a gas passes through a tube, its drop in pressure is a measure of what?
The resistance of the tube (or rather, the resistance the gas had to overcome to move through the tube)
Resistance varies with _______ passing through per________
Resistance varies with the volume of gas passing through per unit of time
Write out the flow (Q) formula
Q = P2 - P1 / R
Q = flow, P = pressure 2 which is the first part of the tube, P1 is the end of the tube and R is resistance
Describe the basics of laminar flow
Flow is smooth/orderly, particles move parallel to the tube walls and flow is fastest in the center where there is less friction
What law governs laminar flow through a tube, taking into account varying pressures, diameter, and viscosity of flow?
Poiseuille’s law
Describe the basics of turbulent flow
Flow lines are not parallel and consist of “eddies.” Unlike laminar flow, the turbulent flow rate is the same across the diameter of the tube
Eddies = composed of particles moving across or opposite the general direction of flow
Describe generalized and localized turbulent flow
General = When the flow of gas through a tube exceeds the critical flow rate
Localized = Gas flow rate is below the critical flow rate but encounters constrictions, curves, or valves
critical flow rate is the point in which gas either acts laminar when below the critical flow rate or turbulent when above the critical flow rate
How does resistance impact patient breathing while on a ventilator?
Resistance imposes a strain if the ventilation mode has the patient doing some of the work. Changes in resistance also parallel changes in the work of breathing
What part of the breathing circuit is most likely to be the greatest point of resistance?
The ET tube
Describe compliance
A ratio of the change in volume to the change in pressure and is measured in ml per cm H20
if you are distensible, then a small change in pressure creates a large change in volume. If you are non-distensible, then a large change in pressure has a small or no change in volume
What are the most distensible components of the breathing circuit?
Breathing tubes and reservoir bags
What factors dictate rebreathing?
FGF, dead space and the design of the breathing system
What is the relationship of FGF and rebreathing?
Inverse; the more FGF you have the less you should rebreathe. The less FGF you have, the more you should rebreathe
What is the factor that determines whether or not the FGF is enough to prevent rebreathing?
Minute volume/ventilation. FGF must exceed this in order for the patient to not rebreathe.
so if your minute ventilation is 5.5 L/min, and your FGF is 6 L/min, you are not rebreathing
What are the four types of dead space listed in lecture?
Apparatus = volume in a breathing system occupied by gases that are rebreathed without change in composition
Physiologic = anatomical and alveolar dead spaces
Anatomical = conducting airways; adds H2O vapor
Alveolar = volume of alveoli ventilated but not perfused
What can decrease apparatus related dead space?
Having the inspiratory/expiratory limb separation as close to the patient as possible
What dead space adds H2O vapor?
Anatomical
When is the inspired gas composition identical to the FGF?
When no rebreathing is occuring
What are 2 physiologic effects of rebreathing?
You reduce heat/moisture loss
What are the desirable characteristics of a breathing circuit?
Low resistance to gas flow
Minimal rebreathing
Removal of CO2 at the rate of production
Rapid changes in delivered gas when required
Warmed humidification of inspired gas
Safe disposal of waste gases
List the classifications of breathing circuits
Open = No reservoir bag and no rebreathing
Semi-open = Reservoir bag but no rebreathing
Semi-closed = Reservoir bag and partial rebreathing
Closed = Reservoir bag and complete rebreathing
What type of breathing circuit is generally used in anesthesia?
Semi-closed
What type of circuit is completely dependent on FGF?
Closed
What components make up a breathing circuit?
A facemask, LMA, or ETT
A Y-piece with mask/tube connectors
Breathing tubing
Respiratory valves
Reservoir bag
A fresh gas inflow site
A pop-off valve leading to scavenging
Carbon dioxide absorption canister
Describe where the anesthesia mask sits on the face
Fits between the inter-pupillary line and in the groove between the mental process and the alveolar ridge
What does the anesthesia mask directly connect to?
The Y-piece or connector
What are the pros/cons of connectors/adaptors on a breathing circuit?
Pros: Extends distance between patient and breathing system, Change angle of connection, Allow more flexibility/less kinking
Cons: Increased resistance, Increased dead space, Additional locations for disconnects
What is the internal volume of the standard breathing circuit?
400 - 500 ml per meter of length
Describe the resistance, distensibility, type of flow and basic characteristics of breathing tubing
It has low resistance, moderately distensible with turbulent flow d/t corrugation. It is large bore, corrugated, plastic and expandable
Assuming there are no issues with the circuit valves, where would you expect to find the circuit related/apparatus related deadspace?
At the Y-piece and distal to it
What pressure do you use during the circuit pressure check?
30 cm H2O
What occurs if the unidirectional valves fail?
The associated limb (expiratory vs inspiratory) becomes dead space
What are the basic characteristics of the unidirectional valves
Direct respiratory gas flow in the correct direction
Disks with knife edges, rubber flaps, or sleeves
Low resistance and high competence
Must open widely w/ little pressure
Must close completely and rapidly w/ no backflow
What does the inspiratory valve prevent? Expiratory?
I = prevents backflow of exhaled gas
E = prevents rebreathing
What is the ideal location for the unidirectional valves?
Near the CO2 absorber canister casing, fresh gas inflow site, and the pop-off valve
What are required features of unidirectional valves?
Arrows/directional words, hydrophobic, open/close correctly, clear dome and place between the patient and the reservoir bag
What are reservoir bags made of? General shape? Range of volume?
Made of rubber or plastic or latex. Ellipsoidal shape and a volume range of 0.5 - 6.0 L
What is the minimum and maximum pressure of the reservoir bag?
30 to 40 - 60 cm H2O
What type of reservoir bag has double the distending pressure of rubber bags?
Plastic
What are the basic functions of the reservoir bag
Reservoir for anesthetic gases or O2
A means of manual ventilation
Assistance with spontaneous ventilation
Visual/tactile monitor of ventilation
Estimation of volume of ventilation
Protection from excessive positive pressure
What is the preferred location of the gas inflow site?
Between the CO2 absorbent and inspiratory valve
What is the other name for the APL valve?
Pop-off valve
What are the basic functions/characteristics of the APL valve?
Permits gas to leave, user-adjustable, dome valve loaded by a spring and screw cap, controls pressure in the system and releases gas to the scavenging system
What occurs if you tighten the APL valve?
As you tighten it, it requires more pressure to open the valve
The APL valve adjusts pressure in the system, how many turns (also indicate in what direction) are required to fully open the valve? Fully close it?
1-2 clockwise turns fully closes the valve from open, 1-2 counter-clockwise turns fully opens the valve from closed
What occurs to the APL valve on inspiration/expiration during spontaneous, assisted/manual and mechanical ventilation?
Spont = closed on inspiration, open on expiration
Assisted = partially open during both
Mech = bypassed on both
be careful with the wording here, it is BYPASSED on mechanical, it doesn’t matter if the APL valve is open or closed if the patient is on the vent because it is bypassed
What occurs during spontaneous respiration if the APL valve is partially closed?
It mimics CPAP
What does the side/center tube of the absorber canister do?
Return gas to the patient
What is the product of CO2 coming into contact with the absorber?
Carbonate, water and heat
What makes up soda lime?
Calcium hydroxide (~80%)
Sodium hydroxide and potassium hydroxide (~5%)
Water (~15%)
Small amounts of silica and clay
When is a CO2 absorber fully exhausted?
When all the hydroxides become carbonates
How much CO2 can soda lime absorb?
19% of its weight in CO2
the exact ratio here is for every 100g you can absorb 26L of CO2
What components make up CaOH lime absorber?
Calcium hydroxide (70%)
Calcium chloride (0.7%)
Calcium sulfate (0.7%)
Polyvinylpyrrolidone (0.7%)
Water (14.5%)
What are 3 possible negative outcomes related to CO2 absorbers?
Compound A formation, CO formation and destruction of inhaled gases
What are the advantage(s) of LiOH as an absorber? What is it’s most common application?
Has much more CO2 absorption capacity, however it is prohibitively expensive and limited to submarine and spacecraft use
What are the characteristics of Litholyme?
Lithium chloride catalyst, no reaction with inhaled anesthetic agents
No activators/strong bases
Does not form compound A and CO
No regeneration
pH indicators do not become colorless
Lower exothermic reactivity, reduced risk of fire, and reduced economic/environmental impact
What are the characteristics of Spira-lith?
Anhydrous LiOH powder within a nongranular partially hydrated polymer sheet
Larger surface area for reaction
No activators/strong bases
Reduced temperature production
Longer duration of use
Cost-effective
No color indicator
How do you size an NPA? What step is important prior to insertion?
Measure from the bony mandible or the nostril to the external auditory meatus and the important step prior to insertion…
What video laryngoscope is this?
King
What video laryngoscope is this?
McGrath
What video laryngoscope is this?
Glide-Scope
What video laryngoscope is this?
Co-Pilot
What type of breathing tube is this?
RAE tube
What kind of breathing tube is this (include all applicable names)?
Armored tube, reinforced, anode or spiral embedded tube
Primary purpose of a laser resistant breathing tube?
It’s in the name; reflect the laser beam
What breathing tube is this?
Laser resistant
the trick here is either look at the surface of it which appears metallic or the easier option is to notice how there are two cuffs at the end of the tube, a hallmark of laser resistant tubes
