Believing that you’re an EMS provider who is “as smooth as butter,” you ask, “Why do I need to read about respiratory distress and failure?” This is a simple emergency. A clinician shouldn’t be shaken.
The reality is this emergency can be challenging to manage and easily can outmatch the caregiver.
Hypoxia can lead to bradycardia
Respiratory distress is an increased work of breathing, with preserved gas exchange (i.e., a patient is working hard, and that hard work no longer is paying off).
Oxygenation or ventilation aren’t adequate to meet the metabolic needs. The patient is in serious trouble.
Respiratory distress and respiratory failure are found on a continuum and often are challenging to distinguish for the novice clinician. A patient can reside anywhere from mild to sick. Additionally, this emergency can be very dynamic and fast moving. Respiratory or cardiac arrest can happen within three minutes for the severely hypoxic patient.
Life-threatening consequences happen when hypoxia leads to bradycardia. Mechanisms by which hypoxia produces bradycardia are well understood.
Hypoxia causes powerful reflexes and directs the effects on the heart’s conduction system. Parasympathetic output increases and sympathetic tone decreases to conserve myocardial oxygen consumption.
The suppression of pacemaker cell depolarization and atrioventricular (AV)-node conduction slows. Hypoxia depresses the sinoatrial node and the AV node, which causes dysrhythmias.
Hypercarbia and an associated acidosis can potentiate bradycardia synergistically by further reducing the pacemaker cells. Hypercarbia expands the vagal tone; myocardial contractility falls. The result: acceleration of bradycardia to pulseless electrical activity to asystole.
Astute clinicians anticipate these and act proactively.
Airway management
To prevent death, aggressively intervene with conventional airway management. For poor airway patency, suctioning and positioning can be indicated.
For critical patients who are having ventilation and oxygenation problems, supplemental oxygen is required for hypoxic states. Nasopharyngeal and oropharyngeal devices are great for gaining airway control. Capnography is an essential tool for measuring respiratory status. It can provide an early warning of impending respiratory failure (even before hypoxia). Sadly, these tools often are forgotten in the moment and aren’t used.
Mechanical ventilation tools (noninvasive) include the use of positive airway pressure, such as continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP) and bag-valve-mask ventilation (BVM).
The use of advanced airways (invasive), supraglottic airway devices and endotracheal intubation can aid when oxygenation and ventilation can’t be achieved with lessor methods. Atropine and pacing aren’t the correct solution for respiratory-induced hypoxia that becomes bradycardic. Save these cardiac tools for a bradycardia from myocardial ischemia or infarction.
Medications
Albuterol, ipratropium, epinephrine, magnesium sulfate, steroids (for wheezing patients) and nitroglycerin (for crackles/rales) can be used based on assessment and sound clinical judgment.
