Review for Final Exam in RSPT 2160 By Elizabeth Kelley Buzbee AAS, RRT-NPS, RCP
Question • Your intubated patient is being bagged at 100% and you see that the Sp02 on her finger is reading 93%. • You would best set up the mechanical ventilator at what Fi02?
answer • If the Sp02 is only 93% on Fi02 100%, we know that the P[A-a]D02 is wide. • We don’t have enough information, so stay at 100% on the mechanical ventilator until we can get an ABG. • Even with an ABG, we really don’t like to make massive changes-it is safer to decrease in steps of about 10-20% at a time [Egan’s pp.1039, Box 41-18]
question • While the anesthesiologist is bagging a patient with no history of lung disease, you need to set up initial ventilatory settings. • If this female patient is 5 feet 3 inch tall, what is her IBW and what would be a reasonable VT?
answer 100 # for 5 feet +[3 x 5] = 115 # IBW 115/2.2 to convert to kg = 115/2.2 =52 kg. At 10-12 mL/kg [Egan’s pp.1009] We could safely start her at a VT of 520-624 ml
Question • While the anesthesiologist is bagging an adult patient with no history of lung disease, you need to set up initial ventilatory settings. • At what mode and respiratory rate would start this patient?
answer • CMC or SIMV are both acceptable modes to start patients with most disorders. • A respiratory rate of 10-12 bpm is reasonable place to start with a person with healthy lungs [Egan’s pp.1009]
question • Your patient has no history of refractory hypoxemia, yet the doctor orders a PEEP of 3 cmH20. • Why is this not a problem.
answer • PEEP of less than 5 are considered physiological PEEP-- similar to that level of PEEP created in the lower airways by the actions of the vocal cords during breathing.
Question • While the anesthesiologist is bagging an adult patient with no history of lung disease, you need to set up initial ventilatory settings. • At what initial flow rate do you want to start with this patient; what flow curve would you pick?
answer • This person could be started at a flow rate of 60- 80 lpm to get a I:E ratio of 1:2 or more. [Egan’s pp.1009] • We want an inspiratory time of about 1 second for an adult [Egan’s pp.1033] • The initial flow curve for most folks could start with square wave or a descending ramp, with adjustments based on problems such as excessive PIP or I:E problems [Egan’s pp.1033]
question • You would look at a pressure-volume loop to determine what kind of problems with a patient who is getting volume-targeted ventilation? [CMV or A/C]
answer • The pressure-volume loop is used to assess compliance. [Pilbeam pp. 197] • pressure-volume loop can be used to look at RAW [Pilbeam pp. 195] • As flow rates change, the pressure-volume loop can be affected. [Pilbeam pp. 195] • pressure-volume loop can be related to WOB, and to failure to trigger due to sensitivity issues [Pilbeam pp. 198] • The pressure volume loop can show you that the Vt is excessive as we see pressures rise without changes in volume
question • Describe the use of monitoring of the pressure curves during volume targeted ventilation.
answer • Other than giving information about PIP, looking at the pressure vrs time curve, • identify inspiratory holds [Pplateau] • watch the base line rise as PEEP is dialed in. • see the effect of gross changes in flow rate which could alter inspiratory time and/or PIP
question • How long do you need to wait before you get an ABG on a patient who has had ventilatory parameter changes?
answer • As a rule, we need to get ABG within 30-1 hour of ventilator parameter changes so that there is time for the patient to stabilize.
question • Your patient [70 kg] has the following ABG on these settings. • CMV rate 12 • Vt 700 cc • PEEP 3 • Fi02 40% You would recommend what parameter change?
answer • The pH and the PaC02 both show that the ventilation is adequate, however the patient has moderate hypoxemia at Fi02 40% • increasing the Fi02 to 66% will raise the Pa02 but we risk 02-toxicity, so a better choice might be to raise the PEEP by 1-2 cmH20
question • Your patient [70 kg] has the following ABG on these settings. • CMV rate 12 • Vt 550 • PEEP 3 • Fi02 30% You would recommend what parameter change?
answer • increase to VT 700 ml [10ml/kg]. this will drop the PaC02 and raise the pH. • The Pa02 of 70 torr is adequate and there is a chance that with increased alveolar ventilation associated with the volume change that this patient’s Pa02 might rise also
question • Your patient [68 kg] has the following ABG on these settings. • CMV rate 10 • Vt 750 • PEEP 5 • Fi02 65% You would recommend what parameter change?
answer • The ventilation is fine; keep VE the same • but we have excessive oxygenation, so we need to decrease the Fi02 from 65% to 40% to get the Pa02 back to WNL.
question • Your patient’s mechanical ventilation is on the following settings: SIMV 12 VT 700 Fi02 35% PEEP 0 What parameter alarms need to be set?
answer • We need to set the VE high and low alarms [+/-10% Pilbeam pp. 132] [+/- 20% Egan’s] • We need to set the low Pressure [5-10 below] and high pressure [10-20 above] alarms • We need to set the Fi02 low and high alarms [+/- 5%] • We need to set the return VT about 100 ml low, Pilbeam says 10% • Low PEEP alarms 2-5 [Pilbeam pp. 132]
Question • Your patient has a cuffed endotracheal tube and you need to measure it. • At what part of the ventilatory cycle should this parameter be measured?
answer • We measure the cuff pressure at end inspiration because the increased airway pressure will increase the pressure inside the cuff –so this is the point where the pressure is going to be its highest
question • What is the effect of a endotracheal tube’s cuff pressure of more than 24 cmH20?
answer • Cuff pressures in excess of 25 mmHg can hamper the capillary blood flow in the trachea so that the tracheal tissue can suffer damage from decreased perfusion
Question • Identify those parameters you would measure and calculate to discover that a patient has suffered some form of airway occlusion?
answer • If there is serious occlusion of the artificial airway, on the ventilator, we would see the following: • Increased PIP with the same Pplateau • Increased RAW [see above] • Decreased return VT & VE especially if the high pressure alarm is functional
Question • List the parameters, waveforms and other indicators that an entubed ventilated patient has increased WOB due to bronchospasm.
answer • Increased resistance to flow would show up: • on the flow/volume loop • Flow curve- signs of air trapping • Volume flow curve • the PIP would rise without Pplateau • The RAW would rise
Question • How would you handle serious cardiac arrhythmias triggered by suctioning?
answer • I would stop suctioning, get the catheter out of the airway and increase the Fi02 100% till the EKG returned to normal • I would watch the Sp02 and the patient’s WOB, LOC and bilateral BBS. • In the future, I would raise the Fi02 for several minutes prior to suctioning and I would watch the level of and the timing of the actual suctioning.
question At 10:00 AM your patient is on mechanical ventilation on the following settings: • CMV 12/ total f 12 • VE 7.5 • VT 700 [10ml/Kg IBW] • PIP 33 • Pplateau 31 • PEEP 6 • Fi02 60% The doctor wants to ‘get this patient off the ventilator this afternoon.” Is this possible?
answer • Before we can wean this patient we need to assess the spontaneous parameters, we need to check the history for a resolution of the original problem, we need to assess the level of sedation/paralytic agents. • This patient seems too comfortable on the current settings- no spontaneous breathing. Maybe we can change the mode to SIMV and decrease the rate to 10 bpm to increase ventilatory demand • Also his Fi02 needs to be less than 50% - we could wean to 45% to get a predicted Pa02 80 torr • But his C static is only 28 ml/cmH20 which implies that his WOB would be too high for him to attempt to breath without help. We could put him on SIMV 10 with PS of 10 -12 and watch his total RR. If it rises more than 20%, we need to increase the PS. • In short, we can start to wean this afternoon, but we may not get this patient off the ventilator that quickly.
Question • If you had a EKG and on lead II you noticed that there are more P waves than QRS waves, what kinds of arrhythmias are we looking at?
Question • We have  extra P waves such as PAC or A-fib,  or we have a complete AV block in which the atria and the ventricle are pacing in isolation from one another. Usually the atria will be faster in this case.
question • Your patient has no pulse and the EKG is completely chaotic and you cannot recognize anything. • What is going on and what do you do?
answer • Course V-fibrillation • We need to start CPR and get patient on a defibrillator or AED
question • When you initially set up a ventilator and forget to increase the Pressure limit to a reasonable level for this patient, what would tell you that you have made a mistake?
answer • The audible and visual high pressure alarm will sound • If you are in volume-targeted or in pressure-targeted ventilator modes, the breath will end prematurely, so that the return VT is lower than it should be. • The inspiratory time might be shortened. • Remember, if you had scanned the settings before placing this on the patient you would have caught this mistake.
question • You are setting up a Servo 900 C and to set a Vt of 550 and a rate of 10 on A/C, you would set the preset VE at what level and the CMV at what level?
answer • In volume control mode, we would set the VE [.550 x 10] at 5.5 LPM. • The CMV is set at 10 bpm
question • You are still setting up the Servo 900 C. after selecting the preset VE at 5.5 LPM and the CMV at 10 bpm, you want to select a I:E of 1:3…. • so what Ti % do you select and after you select it ,calculate the peak flow [flow rate.]
answer • At 1:3 this is 25:75 or 25% • The flow rate is preset VE / Ti% or [5.5 LPM / .25] = 22 LPM
question • If your ventilator starts alarming and you cannot figure out what is going on, what do you do?
answer • Remove the patient from the ventilator and bag while you assess the patient’s VS, BBS & Sp02 • If the patient is alert and anxious, reassure him both verbally and with synchronized bagging with his efforts • Once the patient is stabilized, ask the nurse or another RCP to bag while you trouble-shoot the ventilator & circuit.
question • Define the term “control variable.”