Understanding Mechanical Ventilation Quiz

The inspiratory flow limb of this pressure volume curve is indicated by which letter?

Which of the below steps should improve ventilation and clearance of CO2?

Your patient has a baseline plateau pressure of 20, peak pressure of 23. Suddenly, his peak pressure alarms goes off. Now, his plateau pressure is 22 and his peak pressure is 33. Which of the following list of possibilities would cause these changes in peak and plateau pressures?

Based on the curve above, what minimum level of PEEP would be necessary to prevent alveolar collapse at end-expiration?

How do you assess for increasing resistance in the ventilator circuit?

Your patient is recovering from severe ARDS with improving lung compliance and oxygenation over 4 days. Which of the below scenarios is expected if NO changes are made to the patient’s current ventilator settings?

A 34 y/o male patient with past medical Hx of asthma is brought to your ICU from an outside hospital intubated and on mechanical ventilation. His current settings are: Volume Assist Control - f: 10, PEEP: 5, Vt: 500 and FiO2: 60%. The patient’s vitals are: temp: 37.8, HR: 118, BP: 89/40, RR: 26, sat: 93%. His ABG shows: pH: 7.31/ 48/89/22/Sat: 91%. At the bedside, you note a young man who is sedated, has increased WOB, + decreased airflow with high pitched inspiratory and expiratory wheeze. Which of the below interventions would most likely improve your patients clinical status?

Please choose the best answer that describes the relationship between both curves.

Your patient has a baseline plateau pressure of 20, peak pressure of 23. Suddenly, the vent is alarming for high peak pressures. Now, his plateau pressure is 29 and his peak pressure is 33. Which of the following list of possibilities would cause this change in peak and plateau pressures?

You have decided to use the stress index as a measure of the appropriate PEEP needed to prevent alveolar collapse while minimizing alveolar overdistension. What criteria below must all be met?

57 y/o F w/ hx of UIP with progressive dyspnea, now on 3L home O2, presents with low grade fever, worsening cough with minimal sputum production and hypoxemia with sats 84% on RA, 91% on 15L oxymask. Wt: 112 kg, ht: 5’5”. Vitals: temp: 38.6 C, RR: 30, HR: 134, BP: 90/55, MAP: 67. Her ABG shows: pH: 7.33/40/72/22/90% on ~80% FiO2. Pt is intubated and started on mechanical ventilation due to hypoxia. As her physician, you must decide what ventilator settings to commence. Of note, she has evidence of mild to moderate honeycombing at the lung bases and evidence of diffuse bilateral ground glass patchy opacities. She fits criteria for restrictive lung disease with an FVC 57% normal and an FEV1/FVC ratio of 83%. Her DLCO is 48% predicted and her TLC is 62% predicted from PFTs more than 1 year prior. Please select the most appropriate initial ventilation strategy for this patient.

Which of the below images shows a stress index below optimal recruitment?

Your patient has returned from CT scanner and is noted to be more hypoxic than when he left the unit (sats decreasing from 94% on 40% FiO2 to 86-88% on 40%). You check a peak pressure which is increased from 28 to 34. Additionally, his plateau has increased from 24 to 30. Which of the below scenarios is most likely?

You wish to calculate a patient’s plateau pressure. Which set of steps below would allow you to calculate the plateau pressure (once you set the ventilator display to show plateau pressures)?

Your patient with a new tracheostomy and PEG placed 2 days prior has had abnormal measurements of peak and plateau pressures when you review records over the last 48 hrs. You note that every shift the patient’s peak and plateau pressures decrease just after the patient has a bath, but increase again at the next check. Which is the most likely etiology for this change from the list below?

34 y/o female with history of drug abuse is admitted to the cardiac intensive care unit with confusion, chest pain, ST elevation in II, III and aVf with reciprocal depressions in the lateral leads, pulmonary edema and hypertensive emergency with BP if 230/125, MAP 160. Additional vitals: temp: 37.6 C, HR: 125, RR: 26, Sat: 87% on RA. ABG prior to intubation: 7.30, PCO2: 25, PaO2: 66, Bicarb: 18, Sat: 85% on RA. Wt: 60 kg, Ht: 5’3”. The patient was intubated in the ED and is still paralyzed from a dose of rocuronium prior to being taken to the cath lab. As the critical care fellow on call, you are asked to make recommendations for her ventilator settings. The patient has moderate AKI with a creatinine of 2.6. A CT head does not show evidence of blood although assessment of neurological status is limited due to intubation and sedation. CXR here: diffuse bilateral opacities with small bilateral pleural effusions. Which of the below ventilator settings would be appropriate?

From the above flow and pressure curves, calculated the appropriate AutoPEEP

You are walking on rounds getting sign out when you walk by the room of a patient with COPD and left lower lobe pneumonia. You peek inside the room and notice that the patient’s peak pressure is 34. You remember that this patient’s peak pressure was previously 28-30. You enter the room to investigate further. You perform an inspiratory pause maneuver and calculate a plateau pressure of 24. Which of the below scenarios would not cause these changes in peak and plateau pressure?

A 49 y/o female with PMHx of severe pneumococcal pneumonia and associated ARDS is on her 12th day of mechanical ventilation. She is being managed on pressure assist-control ventilation with a respiratory rate of 16, PEEP of 8, Inspiratory pressure of 18, Itime: 2secs, FiO2: 40%. On day 12 of mechanical ventilation, it is noted that her average tidal volume size is 360 mL. On day 15, her tidal volume is now an average of 420 mL. The respiratory therapist comes to tell you that the patient’s tidal volumes are no longer 6mL/kg predicted body weight. What do you do?

78 y/o female is admitted to the neurointensive care unit after suffering from a subarachnoid hemorrhage. Arrangements are made for CTA and interventional radiology. An area of extravasation is noted branching off the R MCA and a coil is placed with resolution. The patient is returned to the ICU for monitoring and blood pressure control. The patient has no evidence of parenchymal blood or intraventricular blood. At this time, the patient’s vitals are: Temp: 37.6, HR: 115, RR: 18, BP: 106/64, MAP of 78, wt: 74 kg, Ht: 5’8”. Several hours after clipping, the patient is noted to be developing shortness of breath. The patient is currently on oxygen 2L NC but within the next few hours the patient becomes progressively more hypoxic . Her arterial blood gas, on 100% face mask/NRB at 15L is 7.35/35/55/20/sats 88% with a current RR of 25. The decision is made to intubate the patient and place her on mechanical ventilation (paralytics used during intubation). Additionally, the patient’s BP has decreased and currently is 95/52, MAP of 66. A bedside echo is performed which shows evidence of wall motion abnormalities, apical ballooning and EF of 25%. Please choose the most appropriate initial ventilator settings for this patient.

After 30 minutes, you obtain an ABG showing pH: 7.56/24/145/24/sat 100%. The patient is triggering her own breaths at a current respiratory rate of 32. The patient’s current ventilator settings are: Volume Assist Control, Vt: 500, f: 18, PEEP: 5 and FiO2: 100%. What changes to the ventilator would you make at this time?

What other interventions might you make to prevent the patient becoming more alkalotic?

39 y/o male with morbid obesity presents with obtundation to the ED. He is intubated for airway protection with rocuronium and an ABG is drawn immediately post intubation showing pH: 6.9, PCO2: 120, PaO2: 72, Sat: 91% on 70% FiO2, Bicarb: 38. Vitals post intubation: Wt: 278 kg, Ht: 5’10. Temp: 38.7, HR: 130, RR:12, BP: 98/47, MAP: 64, sat: 92%. Blood cultures, urine cultures, and chest X-ray are done. Empiric antibiotic coverage with pipercillin-tazobactam and vancomycin is started for sepsis. Volume resuscitation is commenced for hypotension. Which of the following ventilator settings would be appropriate for this paralyzed patient?

The patient has improved clearance of CO2 with a repeat ABG in 1 hr of pH: 7.32/71/112/37/Sat: 98% on ventilator settings of Volume Assist Control: Vt: 580, f: 24, PEEP: 10, FiO2: 70%. 5 hours later you are examining the patient, you notice that the patient’s peak pressures on the ventilator screen are ranging from 35-38. You decide to check a plateau pressure which is 34. What is your next step in deciding what to do with this patient?

The transthoracic (trans respiratory system) pressure (34 mmHg) minus transpleural pressure (6mmHg) confirms a transpulmonary pressure of 28mmHg. Over the next 6 hrs, however, the patient worsens with elevation of alkaline phosphatase, bilirubin and transaminases. You order an US of the liver and CT scan with IV contrast of the abdomen. Your tests show evidence of cholangitis with secondary gall stone pancreatitis. You begin aggressive hydration for pancreatitis, vasopressor support and continue symptomatic care of the patient. Over the next 4 hours, you notice worsening hypoxia (10 hrs post intubation). Your plateau pressure has increased from 34 to an average of 40, with peak pressures increasing from 38 to 45. Your chest X-ray notes bilateral GGO with a moderate pleural effusion on the left. An ABG is performed which shows a pH: 7.21/72/63/20/Sat: 88% on FiO2: 100%. Current Vent settings are: Volume Assist Control: Vt: 550, f: 18, PEEP: 15, FiO2: 100%. Vitals are: temp: 38.7, RR: 30, HR: 136, BP: 84/42, MAP:56 with sats: 86%. Which of these below causes would NOT be within the differential diagnosis?

What ventilator settings would you consider changing at this time (current settings: Volume Assist Control: Vt: 550, f: 18, PEEP: 15, FiO2: 100%. Vitals are: temp: 38.7, RR: 30, HR: 136, BP: 84/42, MAP:56 with sats: 86%. ABG: pH: 7.21/72/63/20/Sat: 88% on FiO2: 100%. Vitals: temp: 38.7, RR: 30, HR: 136, BP: 84/42, MAP:56 with sats: 86%)?

Based on clinical parameters, imaging etc., you define this patient as having severe ARDS. The patient’s abdomen has been opened, thus minimizing the additive effect of worsening chest wall compliance from the patient’s developing abdominal compartment syndrome. The patient is thrombocytopenic with evidence of DIC and has had continual oozing from his surgical site. He continues to have worsening hypoxia over the next 6hrs (Post ARDS ~ 16hrs). His current ventilator settings are: Vt: 410 mL, f: 25, PEEP: 22, FiO2: 100% with vitals: Temp: 37.9, HR: 129, RR: 35, BP: 89/56 with a MAP of 67 on Norepinepherine 0.2mcg/kg/min and Vasopressin 0.4 units/min, Sat: 87%. Plateau pressure is 32, Ppeak is 35. Current ABG shows 7.22/78/52/22/86%. At this time, what additional therapy is indicated?

52 y/o male s/p kidney transplant 5 years ago is admitted from the ED for hypoxia, SOB and decreased mental status requiring intubation for airway protection. You get limited information about the patient’s history, only knowing that the patient has had delayed rejection of his kidney and has been receiving high dose steroids for treatment. Per the patient’s family, he has had fever with progressive dry cough for several days. He has been getting progressively worse and went to the ED due to his SOB and concerns for new onset confusion. In the ED, a chest X-ray was performed showing normal appearing lungs. On admission to the ED, his vitals are: Temp: 38.3, RR: 32, HR: 119, BP: 113/74, MAP: 87, Sat: 72% on RA, ht is 6’1”, Wt: 87kg and his ABG drawn before intubation is: 7.5/20/52/20/70% sat on RA. The patient is intubated with succinylcholine, etomidate, morphine and versed. The ventilator has been set at: Pressure Assist Control ventilation with Pinsp: 25, f: 18, PEEP:5, FiO2: 100%. After 30 minutes his ABG shows 7.45/28/80/20/94% on 100% FiO2 with a respiratory rate of 23. The patient is started on empiric antibiotics with cefepime and vancomycin, treatment dose bactrim and steroids for potential PJP infection. Over the course of the next 24 hrs, the patient’s chest X-ray evolves to show bilateral ground glass opacities. Over the next 12 hours, his saturations dip to the low 80s while PEEP is up titrated to 14 on 100% FiO2. The patient’s ABG at this time shows: pH: 7.29/49/53/24/ 83%. On Pressure Assist Control Ventilation, what do you expect to see happen?

The patient’s ventilator is showing return volumes of 340-350 mLs. Please select the appropriate changes that should be made with the ventilator in this situation.

Your patient is currently on vent settings: Pressure Assist Control Ventilation with Pinsp: 30, f: 18, PEEP: 18, Itime: 3 secs with FiO2: 100%. (tidal volumes ~ 380mL, with minute ventilation of 8.4L) Vitals are Temp: 36.7, RR: 22, HR: 126, BP: 117/69, MAP of 85, sat: 89%. On day 5 of admission, you are called emergently to the patient’s bedside to evaluate the patient. You are told by the nurse that he was doing fine until he was turned a few minutes ago. Now, his vitals are showing: temp: 36.8, RR: 26, HR: 145, BP: 92/48, MAP: 63, sat: 78% on 100% FiO2. His breath sounds are difficult to appreciate bilaterally but appear absent on the right. The patient is diaphoretic and on percussion you note hyper-resonance on the R side. What do you do next?

25 y/o male is in a motor vehicle accident. He was the front passenger and had significant trauma due to side and front impact from a speeding SUV. He is evaluated and treated for his traumatic injuries including hepatic rupture requiring intraabdominal surgery, comminuted left tibial fracture which underwent ORIF, & chestwall contusions. The patient has been stable post-operatively on mechanical ventilation with plateau pressures of 23-24, peak pressures of 26-27, sating 100% on Synchronized Intermittent Mandatory Ventilation, Vt: 550 mL, f: 12, PS: 10, PEEP:8, FiO2: 40% the first 6 hrs post admission. He has central access (subclavian), a neck brace (pt is sedated), closed abdominal incision and his left leg is bandaged and pinned. On the evening of his post-operatively day zero, the RN asks you to come evaluate the patient for hypoxia and peak alarms being triggered. At the bedside the patient is sedated, vitals show: 5’11’, wt: 91kg, temp: 37.6 C, HR: 120 and irregularly irregular, SBP: 105/72 with MAP: 83, RR: 32, pulse ox: 84%. His peak pressure is 33 on controlled breaths. After increasing the FiO2 to 100%, the O2 saturation improves to 92%. What would you do next to clarify the source of this patient’s acute hypoxemia?

You change the patient to Volume Assist Control mode with settings: Vt: 550mL, f: 12, PEEP: 8, FiO2: 100% to provide a saturation of 93%. Pt is sedated to RASS -2 to calm his anxiety and distress. You decide to assess the patient’s plateau pressure. After confirming plateau pressure will be displayed on the screen, what steps do you take?

The patient’s plateau pressure is 27 (from 23-24). (Remember: peak pressures: 33 from 26-27) What is the most likely etiology of the patient’s source of hypoxemia from the below options?

On your exam, the patient is noted to have minimally decreased breath sounds on the left. You check a CXR and note that the ETT is at or just below the carina towards the right. You pull back the ETT 3 cm and the patient’s peak pressures decrease back to 27. Over the next few hours you are able to titrate the patient’s FiO2 back to 40%. Over the next 24 hrs, the patient begins to have increasing sputum production, fevers and is started on antibiotics for a right middle lobe consolidation. His ventilator settings are: Vt: 550mL, RR: 12, PEEP: 8, FiO2: 40% with oxygen saturation 93%. Over the next 12 hours, the patient’s compliance and oxygenation worsen, with the patient requiring PEEP:12, FiO2: 60% to maintain sats > 90%. On these settings, his Peak pressure is 35 and his plateau is 27. The patient has copious, thick secretions. The night-shift nurse calls you at 2am in the morning because the patient is once again desaturating. Additionally, he has had an increase in his peak pressure to 43. You check his plateau and now it has increased to 35. Which of the below actions would you take to reduce the patient’s elevated plateau and peak pressures?

24 y/o male admitted to the ICU post ingestion of 35 tablets of seroquel. The patient is intubated in the ED for airway protection due to somnolence. Additionally, an OGT was placed and the pt was given 50g of activated charcoal as his ingestion occurred within 30 minutes of arrival to the ED. The patient is transferred to the ICU for monitoring of hemodynamics, cardiac arrhythmias and mental status. On admission, the patient is on ventilator settings of: Volume Assist Control, Vt: 500, f: 12, PEEP: 5, FiO2: 100%. Vitals are: temp: 36.8 C, RR: 12, HR: 70, BP: 122/78 with MAP: 93, sat: 100%. Wt: 80 kg, ht: 5’6”. ABG shows: pH: 7.28/53/312/26/100% , peak pressure: 22, plateau: 16. You wean the patient’s FiO2 to keep sats > 92%. Which other change to the ventilator is most appropriate at this time?

The patient is waking up and begins triggering his breaths at a rate of 23-25 bpm. He is saturating 100% on 30% FiO2. On exam, breath sounds are clear without evidence of wheezes, rhonchi or rales. Which scenario suggests the patient is stable for extubation?

A 76 y/o M with PMHx of tobacco use for > 45 pack years, hx of severe COPD with FEV1 42% predicted presents to the ED with low grade fever, cough with increased sputum production, SOB and hypoxia. On exam, the patient has poor air entry and pronounced end expiratory coarse polyphonic wheezes at the bases. His vitals are: temp: 38.2, RR: 34, SBP: 146/97, MAP: 113, HR: 123, Sat: 90% on 8L NC. Wt: 50kgs, ht: 5’10”. Pt is anxious, cannot speak 2 words without having to pause to breathe, mildly diaphoretic and complaining of chest tightness. CXR is clear with hyperinflation. An ABG is done which shows: 7.31/56/78/30/sat: 92%. You try to calm the patient and treat with BiPAP ventilation but the pt complains of claustrophobia and PTSD. You treat with inhaled beta-agonists and ipratropium, steroids and azithromycin. However, the patient does not improve, his vitals change with temp: 37.9, RR: 41, HR: 133, BP: 102/43, MAP: 63, sat: 87%. You get an ABG (7.22/73/65/30/sat: 86%) and the patient is intubated for impending respiratory failure with versed, fentanyl and rocuronium. Which of the below ventilator settings would be appropriate to initiate at this time?

The patient’s blood pressure improves over the next hour back to 147/79, MAP: 102. Which aspect of the process of intubation and mechanical ventilation caused the patient’s blood pressure to improve?

A 57 y/o M with ESLD presents intubated for airway protection after large volume hematemesis in the field. He is stabilized with blood products and placement of a Blakemore tube prior to receiving emergent TIPS . The patient returns from IR on the ventilator. His current vitals show: temp: 36.3 C, HR: 121, RR: 18, BP: 91/51, MAP 64 on 0.1 mcg/kg/min of Norepinepherine. Wt: 80 kgs; ht: 5’9”. His ventilator is set on Volume Assist Control with Vt: 560mL, f: 16, PEEP: 5, FiO2: 50%. His current ABG shows: 7.3/39/121/18/96%. The patient’s current Hgb: 8.6. Over the course of the next 12 hrs, the patient appears to be improving hemodynamically and is weaned off Norepinepherine. Sedation has been minimized but there is significant evidence of confusion and encephalopathy. The patient is triggering all his own breaths at a rate of ~ 19 breaths per min. He has minimal secretions. He has a positive gag and a cough, but cannot follow any commands. Which of the below scenarios regarding mechanical ventilation would you choose for your patient at this time?

The patient has been doing well and is currently on Pressure Support Ventilation with PS: 11, PEEP:5, & FiO2: 28%. A spontaneous breathing trial is performed on PS 5/PEEP 5. Which of the selections below would make you comfortable to proceed with extubating the patient?

A 67 y/o female is transferred from an outside hospital for failure to wean from the ventilator. On your review of her history, you note that she was initially admitted for septic shock secondary to E. coli bacteremia and UTI (1 week ago). She was intubated on the second day of her admission to the OSH after developing hypoxemic respiratory failure which was later diagnosed as ARDS. The patient was in renal failure, as well, and continues to receive HD daily for diuresis. She is now 6 days post intubation. She has received appropriate antibiotics, steroids for her shock and ARDs. She did not receive paralytics and was not proned during the course of her OSH hospitalization. She has been off vasopressor support for > 48hrs. Her current vitals are: temp: 37.1, RR: 23, HR: 87, BP: 143/86, MAP: 105, Sat: 97%, wt: 52kg, Ht: 5’4” on vent settings Volume Assist Control with Vt: 320mL, f: 18, PEEP: 15, FiO2: 50% with an ABG showing: pH: 7.28/49/114/18/ Sat: 98%. Ppeak: 23, Pplat: 20. What ventilator changes would you make at this time?

Over the next 2 days, the patient slowly improves and she is weaned down to PEEP 10 with FIO2 50%. You decide to extubate the patient and perform a spontaneous breathing trial. Which of the below components is NOT recommended when performing an SBT?

The patient failed her SBT at this time, however, she is awake and breathing on her own. She appears uncomfortable on the ventilator so you decide to transition her to Pressure Support Ventilation. Which factor should you consider in transitioning the patient to Pressure Support Ventilation?