PALS certification: misunderstood concepts & exam tips

Reviewed by Jessica Munoz DPN, RN, CEN

The following are the topics students misunderstand during their PALS test.

Bag valve mask (BVM) ventilation

For emergency providers, bag-valve mask (BVM) ventilation is a crucial skill. This skill is not easy to attain; it requires deliberate practice to master it for use in emergency situations. For effective BVM ventilation, the key factors are:

• A patent airway
• Proper BVM ventilation technique
• An adequate mask seal
• Adequate oxygen delivery (PEEP may be used when clinically indicated, but is not required for routine BVM ventilation)

To ensure a successful procedure, proper positioning of the patient is very important¹. Bag-valve mask ventilation can be performed by one person, but two-person BVM ventilation is preferred. Two-person BVM ventilation is ideal, easier, and more effective because it requires two hands on the mask to achieve a tight seal. During a two-person bag-valve mask ventilation, maintaining a proper mask seal is a tricky task, which is why the more experienced operator handles the mask. The other one squeezes the bag².

Monitor the efficacy of chest compressions

In cardiac arrest, during CPR, the end-tidal CO2 (ETCO2) waveform provides an indirect measure of blood flow generated by chest compressions. ETCO2 reflects systemic blood flow and cardiac output generated during CPR and may indicate chest compression efficacy³. During CPR, the height of the ETCO2 waveform has been used by resuscitators to monitor the efficacy of compressions in real-time and as an indirect measure of adequate chest compressions. An ETCO2 of at least 10mmHg during CPR is generally associated with adequate chest compressions and perfusion; higher values may be seen with more effective compressions⁴. Earlier studies have shown that persistently low ETCO2 values during prolonged resuscitation are associated with poor outcomes; however, termination of resuscitation should not be based solely on ETCO2 and must be informed by the full clinical context and current resuscitation guidelines. While medical professionals provide chest compressions, ETCO2 helps them determine if there is performer fatigue, if compressions need to be deeper, or any other factors that may hinder the ability to achieve and maintain ideal cardiac output. It is a useful adjunct for assessing chest compression quality but should be interpreted alongside other clinical indicators rather than used to define ideal compressions. ETCO2 capnography aids in resuscitative efforts; it can help assess the quality of CPR and the likelihood of return of spontaneous circulation (ROSC), but it cannot reliably predict long-term neurologic outcome or survival.

Compensated and uncompensated shock

The symptoms of compensated and uncompensated shock differ; if the shock is left unchecked and untreated, it can be fatal. That is why it is crucial to treat the shock as early as possible before it reaches the irreversible phase. During compensated shock, the body maintains organ perfusion and blood pressure by increasing heart rate and vasoconstriction, even in the presence of low blood volume. In an emergency, the patient’s mental status, level of consciousness, and other vital signs must be assessed. As sometimes a patient is not frankly hypotensive, it becomes difficult to recognize the shock⁵. The symptoms may include agitation, restlessness, anxiety, nausea or vomiting, rapid breathing, and narrow pulse pressure. In decompensated shock, the body is unable to maintain blood pressure and the perfusion of vital organs. The symptoms include falling blood pressure, altered mental status, and signs of poor organ perfusion such as weak pulses and delayed capillary refill⁶. In cases of decompensated shock, advanced resuscitation measures may be required according to ACLS/PALS guidelines. While treating, priority should be given to addressing the primary cause of the shock. A decrease in blood pressure often indicates late-stage shock. Rapid response is the key to successful shock treatment.

The jaw-thrust maneuver, but you are unable to maintain an open airway

The jaw-thrust maneuver is a noninvasive, manual means that helps restore upper airway patency when the tongue occludes the glottis, which commonly occurs in an obtunded or unconscious patient. Using a jaw-thrust maneuver, an open airway can be established and maintained. This maneuver generates less cervical spine motion than the head-tilt and chin-lift methods⁷, while all three are effective maneuvers for opening the patient’s airway. However, chin-lift and head-tilt methods are easy to perform and maintain. If the jaw-thrust maneuver is not effective, use adjunct airway techniques (such as oropharyngeal or nasopharyngeal airways, if appropriate) and, if there is no concern for cervical spine injury, a head-tilt/chin-lift maneuver to maintain airway patency. Failure to maintain a patent airway can result in severe bradycardia and hypoxemia, which may progress to cardiac arrest if not corrected⁸. Hypoxemia is a decreased level of oxygen in the blood, especially in the arteries. Oxygen saturation in the blood is measured using a pulse oximeter (a small device that clips onto the patient’s finger). Values under 90% are considered low and indicate hypoxemia.

Resources

• https://www.ncbi.nlm.nih.gov/books/NBK441924/
• https://www.merckmanuals.com/professional/critical-care-medicine/how-to-do-basic-airway-procedures/how-to-do-bag-valve-mask-bvm-ventilation
• https://pmc.ncbi.nlm.nih.gov/articles/PMC4187472/
• https://www.nuemblog.com/blog/etco2
• https://www.cdc.gov/dengue/training/cme/ccm/page72318.html
• https://www.ems1.com/airway-management/articles/compensated-vs-decompensated-shock-what-you-need-to-know-2kxpEcjsMP36UNEb/
• https://pubmed.ncbi.nlm.nih.gov/24269083/
• https://pubmed.ncbi.nlm.nih.gov/15777312/