Indications  

·         Cardiac Arrest

·         Myocardial infarction, life-threatening arrhythmia, hypovolemic shock, severe infections such as septic shock.

·         Respiratory arrest

·         Spinal cord or head injuries, drug overdose, pulmonary edema, anaphylaxis, smoke inhalation & high risk delivery (usually leads to hypovolemic shock)

Or situations leading to these conditions: such as showing signs & symptoms (s/s) of approaching arrest.

·         Vital sign deterioration

·         Loss of consciousness

·         Arterial blood gas value deterioration

Non-emergency use of the manual resuscitator: 

·         Increased breaths prior to invasive procedures such as suctioning the tube

·         Backup ventilation in case of power failure

·         Transporting a patient who is on mechanical ventilation

·         Deep breaths to sigh a patient who is breathing shallowly on his own

 

Contraindications

 The only contraindications to bagging are:  

·         When it is known that the patient has a signed & witnessed DO NOT RESUSCITATE [DNR] on her chart.  As soon as this is known to the team, CPR can stop with or without a doctor’s order.

·         CPR has been determined to be futile because of the terminal nature of the patient Please note: Legally, once CPR has started, only a doctor can stop it under those circumstances    

 

Hazards  

·         failure to establish an airway by head manipulation or mal-placement of the tube

·         upper airway trauma can interfere with getting a good seal or getting air past the damaged tissues

·         dental appliances or food in the mouth can be an obstruction

·         vomiting and aspiration will be an obstruction as well as cause chemical burns on the lung

·         must use care with spinal cord injuries

·         jaw thrust: from the head of the bed, you place index fingers on the angles of the lower jaw. Pull the jaw forward without tilting the head or twisting it.

·         bronchospasm can cause excessive pressures because air fails to leave the lungs [air-trapping] Listen to chest while you bag. Let exhalation finish before starting another inspiration

·         Under-ventilation can lead to anoxic brain damage

·         Over-ventilation can lead to barotrauma & decreased cardiac output  

·         inadequate O₂

·         Watch the O₂ lines while you bag. Become aware of tugs on the line and check it periodically to make sure the line is not popped loose.

·         Make sure the flow rate is high enough & that you have adequate reservoir for the bag. Remember that someone could adjust your flow rate so check it periodically.

Characteristics of the ideal face mask [IPPB mask] for resuscitator bags 

·         Adequate seal: no leak. Frequently an air-filled cushion accomplishes this

·         O₂ inlet: extra nipple to attach a O₂ line.  Should have a plug or a one-way valve on it if O₂ is provided some other way. [Usually, it is not needed because the bag itself will have a O₂ inlet]

·         Transparent: must be able to visualize the patient’s face at all times. High risk of vomiting with mask bagging

·         standard 15/22 mm diameter: to fit all bags and other RC devices these devices have standard fittings

·         size: there should be a selection of at least 2 or 3 adult sizes as well as a couple of pediatric and infant sizes [newborn and preemie sizes]

·         Low resistance to airflow: when inlets & ports are too small for the flow rate, there is an increased resistance to flow. The allowable back pressure of such a device is less than 5 cm H₂O at 50 lpm

·         Minimal dead space: design of the mask & its attachment can be too big, so that the bag is filling up the mask and the connectors rather than the lungs. This is called dead space [Vd]

 

Compare the FiO2 of mouth to mouth to mask bagging at various O2 flows  

·         We breathe 21% O₂. At room air, the exhaled O₂ drops to 16%-this is all we can give the patient with mouth to mouth

·         If the person doing mouth-to-mouth inhaled some O₂ at 10 lpm, the exhaled FiO₂ rises to about 32% still not good enough

·         Only when the mode of rescue breathing is changed from mouth to mouth to a bag-valve-mask can the FiO₂ get closer to 100%

     

Compare the FiO₂ of bagging at various 02 flows

Just as with mouth-to-mouth, the increase of FiO₂ into resuscitator bags also will not add much FiO₂.  At no flow the FiO₂ is 21%, if the flow rate is 6 lpm, the O₂ only increases to 28% while at 10 lpm the FiO₂ is only 35%

Conclusion: while increasing the flow rate of the bag does affect the FiO₂, it is not enough. We need something else. We need a reservoir for the O₂ to collect so that more O₂ goes to the patient with each breath

 

Various parts of a typical resuscitator unit  

·         non-rebreathing valve: one way valves that vents exhaled gases out of the bag so that patient will not breath exhaled gases

·         15/22mm adaptor for standardized adaptor for all interfaces

·         exhalation port with adaptor [collection head] to hold a Wright’s Spirometer to measure return Vt and PEEP valves that allow a bit of air to stay inside the lungs

·         O₂ reservoir with a one-way valve into the bag so that as the bag is squeezed the gas goes to the patient port---not back into the bag.

 

Criteria for the ideal resuscitator bag or bagging technique  

·         Must deliver an adequate tidal volume:

·         Neonatal bag: 20-70 ml  

·         Pediatric bag: 70-300 ml

·         Adult bag 800-1200 ml [although the new AHI guidelines say bag during CPR with 500-600 ml Vt]

·         Valves must accept a flow rate of 10-15 lpm for adults [5-10 lpm for kids] without jamming open or closed

·         A reservoir that has a volume at least the size of the bag itself

·         Should have a recoil time fast enough that the bag will re-inflate  completely between breaths

·         Recoil is the time it takes the deflated bag to re-inflate

·         Recoil should allow the RCP to bag with fast respiratory rates

·         For CPR [or “crash carts” ] the bag must be a self-inflating bag that re-inflates with or without extra O₂ flow rate

·         The ideal bag will be made of material that allows the RCP to feel differences in the stiffness of the lung [compliance] or in the resistance to flow

·         Bag must have a non-rebreathing valve so that as the patient exhales, the gas is vented into the room and not blown back into the patient’s face.

·         Bag must be sturdy enough that it can handle being dropped onto concrete from 1 meter height and still function

·         You should be able to shake vomitus or blood out of the valve with a single motion and keep bagging

·         The RCP’s technique should embrace these problems :

o    Recognize a leaky connection & fix it

o    Recognize poor head placement & fix it

o    Recognize that one hand squeeze may not push out the minimal 500-600 mL volume [Reference: AHA 2005 CPR] that you need to deliver for an adult

o    Realize that the ideal FiO₂ of the bag is 85%-100% and that you cannot get that with just increasing the flow rates, but with the addition of a reservoir bag           

 

Factors that affect the delivered volumes of resuscitator bags. 

·         Mask is more difficult to get volume in than the endotracheal tube [poor seals as well as a degree of air gets into stomach]

·         Two hands are better than one

·         Hand size is important, but technique is equally important

·         Lung compliance; the stiffer lung is harder to bag

·         Brand of bag

·         Fatigue: as the RCP becomes tired, his stroke is less effective. Must learn your limitations

·         Gloves do not effect efficiency

·         Operator skill is most important factor

           

Factors that affect the delivery of FiO₂ into the bag  

·         Flow rate too low for the respiratory rate

·         Reservoir is too small for the respiratory rate and Vt of bag

·         Recoil time delays decrease FiO₂ filling as well as limits the Vt

           

Types of reservoirs used to conserve FiO₂  

·         Plastic bags: advantage can easily monitor the adequacy of the flow rate

·         Aerosol hose: 5-inch flex hose can only hold 50 mL of volume, so it is ok for infants to have at least 15 inches. The reservoir needs to be wider not longer for adults

           

The importance of being able to feel the changes in the resistance to flow or the changes in lung compliance thought the walls of the bag.  

·         As the lung fills with fluid as happens when the heart is less effective and blood backs up into the lung, the lung gets stiffer [compliance] and it takes more pressure to send in the same volume [C = ΔV/ΔP]

·         The RCP must apply more pressure to the bag to get the same volume into the patient’s lungs as the lung’s compliance with your efforts decreases

·         As the lung’s airway resistance [RAW] increases due to secretions, other obstructions or bronchospasm, again the pressure used to inflate the lung may have to be increased

 

Compare the following types of non-rebreathing valves.  

·         Diaphragm [leaf valve]:  a moving part that slides back and forth to occlude the bag outlet. It can malfunction easily. It can get stuck by secretions or moisture and sometimes it can be shoved open by excessive flow rates

·         Spring & disc valve: as the bag is compressed, the spring is pushed out of the way and on exhalation the spring recoils so that the bag outlet is occluded

·         Duck bill valve: soft rubber or plastic that is shaped like a mouth. Gas from behind the valve pushes the valve open and gas coming from the patient will close it. Tiny pressure changes will open these valves so that these have little resistance to flow. They are easy for the patient to trigger, and the RCP can watch the valve open and close as the patient breath spontaneously

 

Compare flow-inflated bags to self-inflated resuscitator bags  

·         Flow inflated bags have the disadvantage of always needing an adequate flow rate of gas to work

·         They have the advantage of being the easiest bag to feel changes inside the patient

·         Excessively high flow rates through the flow-inflated bags can raise the PEEP inadvertently

·         If the patient interface slips off the self-inflated bag, it will require a little time to re-inflate

·         The flow-inflated bag can deliver drugs

·         The self-inflated bag has less parts to malfunction or lose            

 

O2-powered manual resuscitator  

·         A high pressure hose attaches to a valve which opens with a finger touch to ventilate the patient then closes for exhalation

o    Disadvantage

§  Operator cannot feel changes

§  Excessive pressures are easy with this method of ventilation so that gastric insufflation can happen

o    Advantages

§  In the hands of a skilled person, the gas powered manual resuscitator can easily ventilate anyone

§  It will deliver high volumes at high rates and 100% O₂ is assured