During ventilation of a child with a bag-valve resuscitator, the pressure relief valve/pop-off continually activates. Which of the following should be your first action?
- Switch to a gas-powered resuscitator
- Bypass the pressure relief valve
- Squeeze the bag more slowly
- Lower the PEEP valve level
If a pressure pop-off continually activates when ventilating a patient with a bag-valve resuscitator, your first action should be to squeeze the bag more slowly. If this fails to lower airway pressure, consider other potential causes (e.g., pneumothorax, endobronchial intubation) before considering bypassing it.
To change the level of negative pressure delivered by a pleural drainage system, you would:
- adjust the vacuum level on the suction regulator
- adjust the water level in the suction control chamber
- adjust the water level in the water seal chamber
- adjust the size of the atmospheric vent
To change the level of negative pressure delivered by a pleural drainage system, you adjust the water level in the suction control chamber.
The purpose of an endotracheal tube stylet is to:
- help ascertain proper tube position
- monitor cuff integrity and pressure
- minimize mucosal trauma during insertion
- add rigidity and shape to ease insertion
An endotracheal tube stylet adds rigidity and shape to the tube for easier insertion during oral intubation (stylets are NOT used for nasal intubation). Lubrication of the stylet facilitates its removal later. To avoid airway trauma, the tip of the stylet must never protrude beyond the distal tip of the ET tube.
An adult patient is receiving 100% O2 via a high flow nasal cannula set to 15 L/min. A persistent high temperature alarms has been occurring over the last several minutes, which you cannot correct. Which of the following actions would be appropriate?
- turn the heated humidifier and its alarm system off
- D/C the device and switch to a nonrebreathing mask at 15 L/min
- add cold water to the humidifier reservoir and reset the alarm
- D/C the device and switch to a standard cannula at 15 L/min
Because high flow cannula humidifier systems are similar to those on ventilators, troubleshooting these devices is also similar. A low temperature alarm can occur briefly when the water reservoir is changed. A persistent high temperature alarm is more serious, generally requiring that the device be discontinued or replaced. If no back-up is available, you should switch to an O2 modality that matches the FIO2 as closely as possible, e.g., a nonrebreather if delivering high FIO2s. Additional serious alarms requiring immediate attention are out of range O2%, failure of the gas supply, or empty water reservoir.
A 12-lead ECG has:
- 8 chest leads and 4 limb leads
- 6 chest leads and 6 limb leads
- 6 chest leads and 4 limb leads
- 4 chest leads and 6 limb leads
A standard 12-lead ECG has only 10 actual leads to place, not 12 (4 limb leads and 6 chest leads). The right leg doesn't really count, since it is just a ground lead. The additional three leads are the augmented limb leads (aVR, aVL and aVF), which use the right arm, left arm and left leg electrodes to obtain their data.
A patient is receiving oxygen via a nonrebreathing mask at 8 L/min. You notice that the reservoir bag on the mask empties during inspiration. You should immediately do which of the following?
- change to a partial-rebreather
- increase the flow
- request a chest x-ray
- intubate the patient
When the bag on a reservoir mask completely empties during inspiration, flow into the bag is insufficient to meet the patient's minute volume needs. The solution is to increase the flow until the bag only partially collapses during inspiration.
If an oxygen blender pressure alarm sounds, which of the following should be your FIRST ACTION?
- verify that the O2 and air lines are providing the required pressure
- check for loose connection or leaks between the gas source and blender
- separately disconnect the O2 and air lines to see if the alarm stops
- verify 100% and 21% O2 settings with a calibrated oxygen analyzer
If an oxygen blender pressure alarm sounds when both gas sources are attached, you should first verify that both gas sources are at the required inlet pressures (usually 35-50 psig). If this is does not correct the problem, you should next check for leaks between the gas sources and blender. If none of these actions resolve the problem, you should replace the blender.
The aerosol is "puffing" out the end of the tubing on a patient who is receiving 40% heated aerosol. This could be caused by
- an empty reservoir jar
- a low flow rate
- poor oxygen entrainment
- water in the large bore tubing
The most likely cause for intermittently "puffing" of mist out the end of the delivery tubing on a patient who is receiving heated aerosol is partial tubing occlusion with condensed water. This partial tubing occlusion will decrease air-entrainment, increase the delivered oxygen concentration and lowers the total output flow of the nebulizer. To correct this problem, you should drain the tubing (away from the nebulizer!)
In a dual-limb or 'Y' circuit, you will increase mechanical deadspace if you place any additional tubing between:
- the heated humidifier and the 'Y' connector
- the 'Y' connector and expiratory valve
- the ventilator outlet and expiratory valve
- the 'Y' connector and the patient's airway
The mechanical deadspace or rebreathed volume in dual-limb circuits is that between the patient connector/swivel adapter and patient airway. Any tubing or device (e.g., an HME) added distal to this point will increase mechanical deadspace.
Shortly after you replace a jet nebulizer and tubing on a patient who has a tracheostomy, the SpO2 drops from 98% to 90%. Aerosol is visible throughout inspiration and expiration in the tracheostomy collar. Which of the following should you do first to resolve the situation?
- Decrease the input flow to the nebulizer
- Ask the patient to breath slower and deeper
- Check the entrainment setting on the nebulizer
- Obtain an arterial blood gas sample for analysis
In general, when troubleshooting oxygenation issues the first step always should be to check the O2 source and confirm that the proper FIO2 is being delivered. Because aerosol is visible throughout inspiration and expiration, the flow is adequate to meet patient needs and thus assure a stable FIO2. Given adequate flow, the only good explanation is that the FIO2 setting on the new nebulizer was not checked and is providing a lower O2 concentration than the prior setup. To correct the problem, readjust the entrainment setting to match the prescribed value.
To maximize the duration of flow/runtime outside the home, liquid portable O2 systems:
- hold about three liters of liquid oxygen
- can be refilled from a liquid O2 base unit
- incorporate a pulse-dose delivery system
- include a battery-powered contents indicator
Liquid portable O2 systems are used in conjunction with a home-based stationary unit, from which they are refilled. Because refilling requires a return to the base unit, it does not extend runtime outside the home. When full the typical unit holds 1-liter of liquid O2 and provides 3-4 hours continuous flow at a typical low flow setting of '2.' A 3 liter unit would triple this duration of flow but would weigh over 12 lbs and not be readily transportable. Thus the best way to maximize portable unit runtime is to incorporate a pulse dosing system that delivers small boluses of O2 only during inspiration.
In assessing a patient receiving volume controlled A/C ventilation, you note a decrease in expired volume, with the high pressure limit alarm sounding. There has been no change in ventilator settings. Which of the following best explains these findings?
- an increase in patient-triggered respiratory frequency
- increased airway resistance or decreased compliance
- the presence of a leak in the patient-ventilator system
- malfunction of the ventilator volume monitoring sensor
During volume controlled ventilation, a decrease in expired volume occurring together with an INCREASED airway pressure (high pressure limit activated) usually indicates an increase in total impedance, as occurs with either an increase in airway resistance or a decrease in compliance. Tube kinking or obstruction or patient-ventilator asynchrony would have a similar effect.
At an FIO2 of 0.30, a pulse oximeter attached to the right index finger of a 6 week-old infant displays an SaO2 of 87% and a pulse of 64/min. A heart monitor reads a simultaneous heart rate of 120/min. Which of the following would be the most appropriate action?
- reposition the pulse oximeter
- increase the FIO2 to 0.40
- ventilate the infant with 100% 02
- suction the infant
When a discrepancy exists between a pulse oximeter's reading and that of another reliable monitoring system (ECG, ABG, etc.), suspect the oximeter. This is because pulse oximeters are notoriously prone to giving false readings, both for SpO2 and heart rate. The most common cause for false reading is malposition of the sensor probe. In this case, repositioning the oximeter's sensor probe should alleviate the discrepancy.
During an IPPB treatment, the machine fails to cycle off. Which of the following actions could you take to correct this problem?
- increase the pressure setting
- replace the IPPB unit/re-attach the breathing circuit
- check the circuit/all connections for leaks and correct
- decrease the available inspiratory flow
Since IPPB devices are pressure-cycled, a failure to cycle to expiration indicates a system leak. In this situation, you should check all tubing connections, the nebulizer fitting and the exhalation valve for leaks.
During a spontaneous breathing trial on a patient with a tracheostomy, the mist disappears at the T-piece early in inspiration. You should
- add deadspace between the T-piece and patient
- direct the patient to inhale more slowly
- decrease the length of tubing from the nebulizer
- increase the flow from the nebulizer
Disappearance of the mist at the T-piece of a nebulizer system early in inspiration indicates inadequate flow (patient flow exceeds system flow). This will result in the patient getting less oxygen than that set on the nebulizer. You should either increase the flow from the nebulizer or use two nebulizers connected in parallel (to double the flow).
Measurement of the O2 of an air entrainment mask results in an incorrect FIO2. You should:
- decrease the oxygen flow
- add a humidification system
- check the entrainment ports
- increase the oxygen flow
Because air-entrainment masks mix air and oxygen at a constant ratio, an alteration in the delivered oxygen concentration could only result from an alteration in the mixing ratio. Since jet size (for a given adapter) is fixed, the problem must be with the entrainment ports. Obstruction of the entrainment ports will decrease air entrainment and raise the delivered oxygen concentration.
Room air will NOT enter the ports of an aerosol face mask if the:
- mask is fitted properly to the patient's face
- nebulizer is set to deliver 100% source gas
- gas flow exceeds the patient's minute ventilation
- gas flow exceeds patient's inspiratory flow
Room air will enter ANY open O2 delivery system (like an aerosol mask) when the patient's inspiratory flow exceeds that delivered by the device. Because on average a patient's inspiratory flow is about three times the minute ventilation (VE), the minimum flow needed to prevent air dilution will be at least that high (3 x VE). Because no air is entrained, a standard jet nebulizer set to 100% source gas cannot deliver more that about 12-15 L/min flow, which is below the 3 x VE rule of thumb for most adult patients. Of course, dilution of source gas with air will lower the FIO2 received by the patient. This problem can be overcome by hooking up two standard nebulizers in parallel or using a gas injection nebulizer.
A patient having just undergone major thoracic surgery is placed on pressure control A/C ventilation with 10 cm H2O PEEP. You observe continuous bubbling in the water seal chamber of his pleural drainage system. Which of the following is the most likely cause of this observation?
- the patient has a pleural effusion
- the suction/vacuum pressure is too low
- the drainage system is obstructed
- the patient has a bronchopleural fistula
Continuous bubbling in the water seal of a pleural drainage system indicates a leak. The leak may be in/at the patient, i.e., a bronchopleural fistula or improper seal at tube insertion point. Alternatively, the leak may be in the collection system, i.e., connecting tubing or chamber system. An obstructed drainage system will cause loss of bubbling in the pressure control chamber or failure of the water seal level to fluctuate with breathing. So in this case the most likely cause of continuous bubbling in the water seal chamber is a bronchopleural fistula.
A 2-year old asthmatic child is placed on an inline small volume nebulizer while receiving volume control SIMV. Shortly after the treatment has started, an alarm on the servo-controlled humidifier is activated. Which of the following is the most likely cause for this alarm?
- empty water reservoir
- low gas temperature
- decreased humidity output
- clogged expiratory filter
The 4-6 L/min of additional unheated gas flow added to the circuit when using a small volume nebulizer will lower the temperature at the patient’s airway, which can trigger a humidifier alarm. Either the humidifier’s low temperature alarm should be readjusted during treatment or an electronic drug nebulizer (ultrasonic or mesh) should be used to avoid adding extra flow to the ventilator circuit.
An IPPB device set in the air-dilution mode is powered by 100% oxygen. Which of the following is true about this situation?
- The FIO2 will be 0.21
- The FIO2 will be between 0.40 and 0.80
- The FIO2 will be 1.0
- The venturi will not operate
When driven by 100% O2, and operating in the air-dilution mode, the FIO2 provided by an IPPB device varies according to the amount of air entrained. Because air entrainment decreases as the system pressure increases, FIO2s are neither stable nor predictable, ranging anywhere from 0.40 to 0.80. In general, the higher the end-inspiratory pressure and the longer the inspiratory time, the greater will be the average FIO2.
In which chamber of a three-chamber pleural drainage system would you expect to see fluctuations of the fluid level with each breath?
- collection chamber
- water seal chamber
- suction control chamber
- all three chambers
When properly set-up and working, the water in the suction control chamber of a three-chamber pleural drainage system should constantly be bubbling, and the water level in the water seal chamber should fluctuate with the patient's breathing or the ventilator cycle. This indicates that the system is working and the chest tube is patent and functioning without leaks.
An intubated adult patient with severe expiratory airway obstruction requires ventilatory support. Which of the following capabilities would be most important in selecting a ventilator for this patient?
- ability to compensate for airway interface leaks
- variable flow control and adjustable I:E ratios
- ability to run on 12 volt DC (battery) power
- certification for use during MRI procedures
Of the functions listed, the most important capability when selecting a ventilator for an intubated adult patient with severe expiratory airway obstruction would be variable flow control and adjustable I:E ratios. This will allow clinicians to make sure the expiratory time is sufficiently long to prevent air-trapping/auto-PEEP
To maximize the FIO2 delivered by a manual bag-valve resuscitator you would:
- attach a PEEP valve
- decrease bag refill time
- remove the inlet valve
- increase bag refill time
The oxygen concentration delivered by a manual resuscitator (bag-valve-mask) depends on 1) the flow of oxygen into the bag, 2) the size of the oxygen reservoir, and 3) the bag refill time/rate. The greater the input flow, the larger the reservoir, and the longer/slower the bag refill time, the higher the FIO2.
In a dual-limb ventilatory breathing circuit, the proper position for placing a heat and moisture exchanger (HME) is:
- in the inspiratory limb, between the ventilator outlet and the 'Y' connector
- distal to the ventilator's expiratory flow and pressure sensors
- in the expiratory limb, between the 'Y' connector and ventilator inlet
- between the 'Y' connector and the patient's airway
If a heat and moisture exchanger (HME) is used for humidification, it must be placed to assure bidirectional flow, i.e., distal to the patient connector/ swivel adaptor in a dual-limb circuit and between the expiratory valve and patient airway in a single-limb circuit.
When preparing to replace a prefilled sterile disposable water reservoir on a mechanically ventilated patient's heated humidifier, you note that the water in the new bottle is milky in appearance. You should:
- send a sample to the lab for culture
- use if expiration date has not passed
- obtain a new replacement bottle
- switch the patient to an HME
If the water in a disposable humidifier or humidifier reservoir appears contaminated in any way, you should discard it and replace it with a new one.
Which of the following types of breathing circuits would you select when assembling a noninvasive positive pressure/BiPAP ventilator?
- dual-limb "Y" circuit
- single-limb circuit with expiratory balloon valve
- single-limb circuit with leakage-type exhaust valve
- single-limb circuit without any valve
Most noninvasive positive pressure (NPPV) ventilators/BiPAP devices use single-limb circuit with a leakage-type exhaust valve. These circuits consist of a single section of large-bore tubing and an open exhaust port, usually either a small orifice or a set of slotted vent holes. The continuous flow that noninvasive positive pressure ventilators provide through the circuit forces expired gas out this exhaust port during exhalation.
When suctioning an adult intubated with a 8 mm endotracheal tube, you suddenly lose vacuum pressure. Which of the following is the likely cause?
- displacement of the ET tube
- suction tubing disconnection
- clearance of secretions
- a mucus plug in the ET tube
The two most common conditions that would cause a sudden loss of vacuum pressure during suctioning are (1) disconnected tubing (leak; loss of vacuum) or (2) a full suction collection reservoir (ball-valve shut-off). Normal clearance of secretions would not cause loss of vacuum, nor would displacement of the ET tube or its obstruction by a mucous plug.
You note that the reading from a pulse oximeter equipped with a disposable finger probe has decreased from 93% to 71%, without a change in FIO2 or patient condition. The most likely cause is that the:
- oximeter unit needs to undergo recalibration
- probe is overheated and should be moved
- probe/probe site needs to be warmed to 42 degrees Celsius
- probe or probe cable is malfunctioning
Were a patient's Hb saturation to really drop from 93% to 71%, severe hypoxemia would occur and there would be a dramatic change in the patient condition (an SpO2 of 71% corresponds to a PaO2 of 40 mm Hg or less). Since pulse oximeters do not require manual calibration, the most likely problem is equipment malfunction, i.e., probe or probe cable is malfunctioning and should be replaced. And unlike transcutaneous ABG monitors, pulse oximeter probes do not require warming to provide accurate data.
Which of the following would most affect the accuracy of a capnometer’s end-tidal CO2 (PetCO2) measurements?
- water vapor
- O2 concentration
- system leaks
- patient fever
PetCO2 levels vary normally according to the patient's CO2 production (metabolic rate), breathing pattern, deadspace and VT. Significant errors in measurement can occur due to leakage of air into the system or the presence of liquid water on the sensor or in the sampling line. Because PetCO2 measurements are standardized to BTPS conditions, neither the presence of water vapor nor the patient’s body temperature will affect instrument accuracy. Variations in O2 concentration have minimal effect on device accuracy, with most units providing automatic compensation for FIO2.
An intubated patient with COPD who is in acute respiratory failure requires a ventilator. To optimize support of this patient you would recommend a ventilator capable of:
- airway pressure release ventilation
- pressure support with adjustable off-cycling
- mandatory minute ventilation
- high frequency oscillation ventilation
Intubated patients typically require pressure support (PSV) to help overcome the extra work imposed by the artificial airway during spontaneous breaths. Unfortunately, during PSV many COPD patients experience a slower rise and decrease in inspiratory flow which can delay off-cycling and increase auto-PEEP. The ability to adjust the PSV off-cycle (to a higher % of peak inspiratory flow) in patients with COPD can improve patient–ventilator synchrony and reduce inspiratory muscle effort.