RC 255 Exam 2
Calculating Airway Resistance: RAW
(Pta)/ flow -cmH2O/L/sec
Calculating Dynamic Compliance: Cdyn
(Vt)/ (PIP-PEEP) - ml/cmH20
Calculating Static Compliance: Cstat -True lung compliance
(Vt)/ (Plat-PEEP) - ml/cmH2O
Type of flow curve produced by volume ventilation
- Ascending Ramp - Sinusoidal
Priorities when it comes to vent alarms (ie patient assessment, patient ventilation/oxygenation)
- Check patient first - Manually ventilate as needed - Recognize signs of respiratory distress
Common causes of high pressure alarm
- Conditions related to the airway * Coughing * Secretions or mucus in the airway * Patient biting on the ET (oral intubation) * Biting or kinking of the ET inside the mouth or in the back of the throat * Impingement of the ET on the trachea or carina [ migration of the tube into the right mainstem bronchus] * Herniation of the ET cuff over the end of the tube - Conditions related to the lungs * Increased airway resistance ; secretions, mucosal edema, bronchospasm * Decreased compliance ; pneumothorax, pleural effusion * Patient ventilator asychrony - Changes in the ventilator circuit * Accumulation of water condensate in the patient circuit * Kinking in the inspiratory circuit * Malfunction in the inspiratory or expiratory valves
Absolute contraindication to PEEP
- Hypovolemia - Untreated Pneumothorax - Tension Pneumothorax - Intracranial Pressure - Hyperinflation - Pulmonary Effects of PEEP - Transmission of Airway Pressure to Pleural Space [Slide 37]
The 4 types of Hypoxia are
- Hypoxemic Hypoxia - Anemic Hypoxia - Circulatory Hypoxia - Histotoxic Hypoxia
A 68-year-old woman was admitted to the ICU with pneumonia and was intubated when she developed progressive hypoxemia. She has been on the ventilator for 5 days and has been tolerating this therapy well. The patient has suddenly become severely agitated and appears to be fighting the ventilator. The ventilator's high pressure alarm is sounding continuously. The respiratory therapist disconnects the patient from the ventilator and begins manual ventilation with 100% oxygen and PEEP. The resuscitator bag is difficult to squeeze, breath sounds are present on the left with no adventitious sounds and absent on the right side, and percussion reveals hyperresonance over the right side.
- Insert a 14 gauge needle
Causes of metabolic acidosis
- Pancreatitis - Renal Failure - Aspirin - Diarrhea - Diabetic Ketoacidosis - Lactic Acid
Common causes of low pressure alarm:
- Patient disconnection - Circuit leak - Disconnection of the inspiratory/expiratory tubing of the ventilator circuit * Humidifiers * Filters * Water traps * Inline metered dose inhalers * Proximal pressure monitors * Flow monitoring lines * Exhaled gas monitoring devices * Inline closed suction catheters - Temperature monitors - Exhalation valve leakes * Cracked or leaking valves * Unseated valves * Improperly connected valves - Airway leaks * Use of minimum leak technique * Inadequate endotracheal tube (ET) cuff inflation * Leak in pilot balloon or cut pilot balloon * Rupture of ET cuff * Migration of ET into upper airway above the vocal cords - Chest tube leaks
Assess, gather data, and take appropriate action (ie trouble shoot) for a variety of clinical conditions (e.g. pneumothorax, ruptured cuff, ETT kinking, plugging of the ETT, ETT misplacement, etc.).
- Pneumothorax: Insert a 14/16 gauge needle into the 2nd intercostal space at the mid- clavicular line - Bronchospasm: Increased RR/HR/WOB/PIP/RAW/Ve/Wheezy Flow volume loop looks moon shaped Measure with PEEPi FIX: With Bronchodilator - Excessive Secretions: Associated with CF/Infection *Use humidity FIX: Suction/Increase PIP/Postural Drainage/Percussion/Therapeutic Bronchoscopy -Ruptured Cuff -ETT Kinking: Manually ventilate, pass suction catheter, reposition the artificial airway [ deflate the cuff] Plugging: First suction, if not resolved extubate and reintubate. * If tube is obstructed; deflate cuff if unresolved extubate, and ventilate with a BVM - Biting: FIX with a bite block
Causes of decreased Cs
- Pulmonary Edema - Atelectasis - Consolidation - Pneumonia - Pneumothorax - Hemothorax - Pleural Effusion - Air Trapping - ARDS
Causes of decreased Cd
- Pulmonary Edema - Atelectasis - Consolidation - Pneumonia - Pneumothorax - Hemothorax - Pleural Effusion - Air Trapping - ARDS - Bronchospasm - Secretions - Tube obstruction - Tumors
A patient's transairway pressure (PTA) is rising while the plateau pressure (Pplateau) remains unchanged. The treatment plan that could correct this problem includes which of the following? -
-Administer a bronchodilator -Suction airway secretions
Increased PIP only = decreased Cd, increased RAW (airway obstruction)
-Could be caused by inflammation in the lung due to pneumonia -ARDS - fluid and other "inflammatory goo" could be accumulating in the lungs
Causes of metabolic alkalosis
-Hypos [ Vol/K/C] - Diuretics - Vomiting/NG Suction - NaHCO3 Infusion/Ingestion - Loop Diuretics
The term used to describe a ventilator graph that has two variables plotted on x and y coordinates
-Loop
The data on the following ventilator flow sheet for a patient being ventilated in the volume-controlled continuous mandatory ventilation (VC-CMV) mode demonstrates which of the following? Time PIP (cm H2O) Pplateau (cm H2O) PEEP (cm H2O) 0800 35 30 5 1000 39 34 5 1100 45 39 5 1130 50 44 5 -Airway resistance is increasing. -Lung compliance is decreasing. -Dynamic compliance is increasing. -Water is accumulating in the patient circuit.
-Lung compliance is decreasing.
•Raw = (Pta)/(Insp flow in L/S)
-Normal 0.5-2.5 cmH2O/L/Sec @ 30L/min -With ETT = 4-8 cmH2O/L/Sec Divide LPM by 60 to get L/sec
•CD = (Vt)/(PIP-PEEP)
-Normal 40-70 ml/cmH2O
The normal range for airway resistance
0.5 - 2.5 cmH2O/L/sec @ 30 L/min With ETT 4-8 cmH2O/L/sec
Common alarm situations:
1. Low-pressure alarm 2. High- pressure alarm 3. Low PEEP/CPAP alarm 4. Apnea alarm 5. Low-source gas pressure or power input alarm
What is the optimal PEEP level given the following information? 8 cm H2O 10 cm H2O 12 cm H2O 15 cm H2O
10cmH20
A patient with COPD is treated with prednisone, theophylline, a lasix (furosemide). Which of the following is the most important parameter to check regularly? 1. Clotting times 2. Calcium levels 3. Potassium levels 4. Pupillary response
3. Potassium levels
A 6'2" male patient is being ventilated in the volume-controlled continuous mandatory ventilation (VC-CMV) mode with: a set tidal volume (VT) of 650 mL. There is 40 mL of mechanical dead space. Calculate the final alveolar volume. 439 mL 445 mL 510 mL 535 mL
6'2= 74 inches 14x2.3 =32.2 32.2+50 = 82.2 82.2 x 2.2 = 181lbs 181 = IBW VA= (Vt-Vm-Vd) x f Va= ( 650 - 40 - 181) = 429
During mechanical ventilation of a patient with COPD: PaCO2 = 58 mmHg Ve = 5.5 L/min. The desired PaCO2 for this patient is 45 mm Hg. To what should the Ve be changed? 4.3 L/min 4.8 L/min 6.6 L/min 7.1 L/min
7.1 L/min Target Ve = CaVa/Cd 58x5.5/45= 7.1 L/min
A male patient (76-kg IBW) with no history of pulmonary disease is brought to the emergency department for treatment of a drug overdose. He is intubated and placed on mechanical ventilation with: VC-CMV f = 12/min VT = 450 mL. The resulting arterial blood gas values are: pH 7.32, PaCO2 53 mm Hg HCO3- 25 mEq/L. The most appropriate action to correct the acid-base disturbance is which of the following? Increase VT to 595 mL Increase VT to 760 mL Increase frequency to 16/min Decrease frequency to 10/min
76 x 2.2 = 167 = Vd Ve = Vt x RR 450 x 12= 5400 = 5.4L/min Target Ve = CaVa/Cd 53x 5.4/40 =286.2/ 40 = 7.2 L/min 450 x 16= 7.2 - Increase frequency to 16/min -Increase VT to 595 mL *Increase tidal volume first
Administer a bronchodilator
A patient is receiving ventilation with volume-controlled continuous mandatory ventilation (VC-CMV). During a patient-ventilator system check the respiratory therapist sees the flow-volume loop below. The most appropriate action is to do which of the following? High airway resistance
Flow Time Scalar in VC
A= Inspiratory valve opens and inspiratory gas begins to flow into the lung B= Achieved peak inspiratory flow that is set on the vent C= Inspiratory flow stopped due to a 0.25 second inspiratory pause D= Expiratory Valve opens and gas flows through the expiratory valve I:Time= A-D : 0.75 Seconds Peak Inspiratory Flow Rate= 80 lpm Expiratory Time= D-F : 1.5 seconds
During pressure-controlled continuous mandatory ventilation (PC-CMV) the respiratory therapist observes the pressure-time scalar shown. The most appropriate action to take is which of the following? -Adjust the inspiratory time. -Increase the flow rate setting. -Adjust the inspiratory rise time control. -Increase the peak inspiratory pressure setting.
Adjust the inspiratory rise time control.
Which of the following can activate an apnea alarm?
Auto-PEEP
The pressure at which large numbers of alveoli are recruited, and should be used to determine PEEP level, in a patient with acute respiratory distress syndrome (ARDS) is located on the static pressure-volume curve at which of the following? -Upper inflection point -Lower inflection point -Peak inspiratory pressure -Between the lower and upper inflection points
Between the lower and upper inflection points = Set vent pressures. Lower inflection= set PEEP Upper inflection= PIP -Lower inflection point
The location at which large numbers of alveoli become recruited and also overinflated on the static pressure-volume curve and how you should set PEEP and PIP based on these.
Between the lower and upper inflection points = Set vent pressures. Lower inflection= set PEEP Upper inflection= PIP
Using calculations to adjust ventilation to hit a desired PaCO2 (there are many of these)
CaVa/Cd 1. Increase Vt first if respiratory acidosis (increased PaCO2/decreased pH). To a max of 8 ml/kg- if out of range increase RR 2. Decrease RR first if respiratory alkalosis ( increased PaCO2/decreased pH). To a minimum of 10/min. If target Ve not reached then decrease Vt
An intubated patient is receiving mechanical ventilation with the following settings: VC-CMV, rate = 18, VT = 850 mL (10 mL/kg), PEEP = 5 cm H2O, flow rate = 40 L/min. The patient is sedated and is not assisting the ventilator. During a patient-ventilator system check, the respiratory therapist observes the following ventilator graphic:
Decrease the rate
The type of flow curve produced by pressure control ventilation is which of the following?
Descending
The flow waveform that produces the lowest peak pressures
Descending ramp: most natural and more comfortable for patient
When an alarm is activated on a ventilator, the respiratory therapist's first priority is to ______________. -Assess the patient's level of consciousness -Ensure adequate ventilation and oxygenation -Assess lung compliance and airway resistance -Ensure that bilateral and equal breath sounds are present
Ensure adequate ventilation and oxygenation
During mechanical ventilation of a patient with CHF: PaO2 = 38 mm Hg FIO2 = 0.6. Desired PaO2 is 60 mm Hg The FIO2 needs to be changed to which of the following? 0.65 0.75 0.85 0.95
FaPOd/POa 0.6 x 60/ 38 .6x60= 36 36/38 =.95 0.95
Calculate flow cycle %
Flow where breath ends/Peak flow
Sensitivity
Identify the improperly set ventilator parameter using the scalars shown below. It should be more sensitive
Using sample FiO2 and PaO2 determine when PEEP should be initiated
If FiO2 increase above 40% add therapeutic PEEP (3 cmH2O at a time)
A patient with ARDS is being mechanically ventilated with: FiO2 of 90% PEEP of 16. The patient's PaO2 remains in the low 50s. According to the ARDSnet protocol what should be your next adjustment? Increase the FiO2 to 1.0 Increase the PEEP to 18 cmH2O Decrease the FiO2 to 0.6 Increase the PEEP to 20 cmH2O
Increase the PEEP to 18 cmH2O
Low and High Pressure alarms
Low Pressure [Leak] #1 Patient disconnect/circuit leaks - Disconnect of inspiratory/expiratory tubing [humidifiers, filters, water traps, inline metered dosed inhalers, inline nebulizers, proximal pressure monitors, flow monitoring lines, exhaled gas monitoring devices, inline suction catheters] -Temperature monitors - Exhalation valve leaks [cracked leaking valves, unseated valves] - Airway leaks [MLT, inadequate tube cuff inflation, leak in pilot balloon, rupture of ET cuff, migration of ET into upper airway above vocal cords] - Chest tube leaks High Pressure [obstruction] - Coughing, secretions, mucus in airway, patient biting on ET tube, kinking of ET inside mouth or back of throat, impingement of ET on trachea/carina, changes in the position of ET, herniation of cuff over the end of the tube - Increased Airway Resistance- RAW[ secretions, bronchospasm, mucosal edema] - Decreased compliance [ pneumothorax, pleural effusion
Calculate IBW for males and females
Men 50+2.3(height in cm-60)Women 45.5+2.3(height in cm-60)
The respiratory therapist enters the room of an intubated and mechanically ventilated patient to find the low pressure, low exhaled volume, and low VE alarms active. The ventilator circuit is connected to the patient's endotracheal tube. This situation could be caused by which of the following?
Migration of the ET tube into the upper airway.
Patient-related causes of respiratory distress in MV
Most common causes: -Artificial airway problems [placement & patency] - Pneumothorax -Bronchospasm - Secretions Other causes: - Pulmonary edema - Dynamic hyperinflation - Change in body position - Respiratory drive abnormalities - Drug-induced distress - Abdominal distention - Pulmonary embolism
Transairway Pressure (Pta)
Pm - Palv (difference between mouth and alveoli)
Recognize and remedy pressure "overshoot"
Pressure is too high when there's an "overshoot". - Correct it by increasing the rise time or slope
Scalar is graphed relative to time:
Pressure time Volume time Flow time
Types of Loops
Pressure-Volume Flow- Volume To determine compliance and resistance
The significance of an increased arterial-to-end-tidal partial pressure CO2 gradient
Pulmonary Embolism
An increased arterial-to-end-tidal partial pressure CO2 gradient can help identify which of the following Pulmonary embolism Dynamic hyperinflation Cardiogenic pulmonary edema Noncardiogenic pulmonary edema
Pulmonary embolism
The type of flow curve produced by volume ventilation with constant flow?
Rectangular
The respiratory therapist is called to the bedside of a patient mechanically ventilated in the VC-CMV mode because the low pressure, low exhaled tidal volume, and low exhaled minute volume alarms all have activated. Which of the following could be the cause of this situation? -Patient biting the endotracheal tube -Rupture of the endotracheal tube cuff -Slipping of the endotracheal tube into the right mainstem -Plugging of the airways by airway secretions and mucus
Rupture of the endotracheal tube cuff
The respiratory therapist enters the room of an intubated and mechanically ventilated patient to find the high pressure, low exhaled volume, and low VE alarms active. This situation could be caused by which of the following?
The patient biting on the endotracheal tube.
Administer a bronchodilator
The respiratory therapist observes the pressure-time scalar seen below. Wave A was generated at 1300 hour and wave B at 1600 hour. The action that is most appropriate for this situation is which of the following? .
The ventilator graphics generated by mechanical ventilation with pressure-controlled continuous mandatory ventilation (PC-CMV), rate 18, peak inspiratory pressure (PIP) 25 cm H2O, positive end-expiratory pressure (PEEP) 5 cm H2O, are shown in the scalars. Interpretation of these scalars reveals which of the following?
There is air trapping that could be due to a high respiratory rate
Volume control, what is the trigger
Time: RR set Limited: Volume Cycled Time
Pressure Support
Triggered: Flow-by patient Limited: Pressure Cycled: Flow
The normal tidal volume range for vent adjustments
Use 6-8ml/kg for vent adjustments Keep Pplat <30cmH20
Difference between pressure control and volume control?
VC: Volume is controlled, but pressure varies Flow: remains constant [ with rectangular waveform] Pressure waveform is ascending ramp [varying with lung characteristics] PC: Pressure controlled [limited], but volume varies Flow: varies Continuously decelerating flow waveform Pressure waveform is rectangular
A male patient is 70 inches tall. What is their anatomical deadspace? 150 ml 73 ml 161 ml 212 ml
VDanat= 1ml/lb IBW IBW = 50 +2.3 x height in inches above 60 inches 2.3 x 10 = 23 50+23= 73kgs 73kg x 2.2lbs = 160.6 =161ml
Calculate the final alveolar volume if given deadspace
Vt-Vdmech-Vdanat
Decreased compliance
What is the cause of the change from pressure-volume loop A to pressure-volume loop B during volume-controlled continuous mandatory ventilation (VC-CMV)? Anytime it gets more flat = decreased compliance
1.5 seconds
What is the expiratory time shown in the flow-time scalar below?
50%
What is the flow-cycle setting for the pressure support ventilation (PSV) breaths shown in the scalars below? 40/20= 50%
The term used to specify the flow, pressure, and volume waveforms that are graphed relative to time is called
scalar
CS = (Vt)/(Plat-PEEP
•Normal 70-100 ml/cmH2O -5 ml/cmH2O for 3 Kg infant
