EMT Chapter 10

This chapter introduces the concepts of respiration and artificial ventilation, emphasizing how to keep a person alive with breathing assistance and determining the appropriate level of support. It begins with a review of the physiology and pathophysiology of breathing, including ventilation (moving air in and out) and the mechanics of inhalation and exhalation. Key terms like tidal volume and minute volume are revisited to assess breathing adequacy.

The video explains where gas exchange occurs (in the alveoli) and the role of diffusion in moving oxygen and carbon dioxide between the lungs and the bloodstream, and then to the cells. It highlights the importance of both a healthy respiratory and cardiovascular system, explaining that a failure in either can lead to a V/Q mismatch and a sick patient.

Various mechanical failures and obstructions can lead to respiratory issues. These include physical trauma to the chest (e.g., stab wounds), loss of nervous system control over breathing muscles, painful chest wall injuries, and bronchial constriction due to conditions like asthma, bronchitis, pneumonia, or COVID-19. Other problems include insufficient oxygen in the air, difficulties in gas diffusion across alveolar barriers due to mucus buildup or chemical damage, decreased blood perfusion, and issues with hemoglobin transport (e.g., anemia, carbon monoxide poisoning).

The brain needs oxygen to survive, and breathing is triggered by hypoxia or hypercapnia. The body compensates for cardiopulmonary system failure by increasing breathing rate, heart rate, and blood pressure to improve organ perfusion. Respiratory distress occurs when compensation is working, with normal mental status and pulse oximetry, but the body is working harder. Respiratory failure is when compensation is no longer effective, leading to cyanosis, altered mental status, and poor perfusion. Respiratory arrest is when breathing stops entirely. The goal is to intervene during respiratory distress to prevent failure or arrest.

To determine if breathing is inadequate, one must assess if the patient is breathing, if their breathing is adequate (chest rise and fall, air movement, normal skin color), and their respiratory rate, rhythm, and quality. Signs of inadequate breathing include altered mental status (anxiety, irritability), uneven chest movement, slow pulse (especially in children), use of accessory muscles (belly, clavicles), abnormal breathing sounds (wheezing, stridor, gurgling, gasping), respiratory rates below 8 or above 24 breaths per minute, shallow or very deep breathing, cyanosis, an abnormal inspiration/expiration ratio, inability to speak full sentences, retractions, pulse oximetry below 95% (or 90% at altitude), and a tripod position.

Hypoxia, insufficient blood oxygen to the tissues, can result from decreased oxygen in the environment (e.g., fire, confined spaces), underlying lung conditions (emphysema), overdose (opioids), or medical emergencies (heart attack, stroke, embolism). Most patients with respiratory difficulties require oxygen. The level of intervention depends on the patient's breathing ability: artificial ventilations for non-breathing patients, non-rebreather mask for inadequate breathing, and nasal cannula for mild oxygen needs. It is better to be overly aggressive than not aggressive enough with oxygenation.

Positive pressure ventilation involves pushing air into the lungs for patients who have stopped breathing or have very inadequate breathing. Negative side effects can include decreased cardiac output and blood pressure. Improper airway opening can lead to gastric distension, which can cause vomiting and further airway issues. Hyperventilation should be avoided, as it can cause vasoconstriction and is often seen during CPR due to provider anxiety. The three primary methods for artificial ventilation are mouth-to-mask, two-rescuer bag-valve-mask (BVM), and one-rescuer BVM, listed in order of preference. Never ventilate a patient who is actively vomiting or has vomit in their airway. Look for chest rise and fall with each ventilation.

Mouth-to-mask ventilation provides good pressure control and uses barrier devices like pocket masks to prevent disease transmission. Pocket masks can be connected to oxygen to increase the oxygen concentration delivered. Proper head positioning (head-tilt chin-lift, or jaw-thrust for suspected spinal injury) and a good seal are crucial. BVMs offer better infection control and come in various sizes for adults, children, and infants. They often have oxygen reservoirs to deliver 100% oxygen. Two-person BVM technique is preferred for a better seal, while one-person BVM requires more practice to achieve a good seal. If chest rise is not observed, check mask seal, head position, and for airway obstructions. In CPR, ventilations are coordinated with chest compressions (30:2 for adults; 15:2 for children with two rescuers). With an advanced airway, ventilations are given every 5-6 seconds.

Patients with a stoma (a hole in the neck into the trachea) require special ventilation techniques. For complete stomas, a pediatric mask is used directly over the opening, keeping the head neutral. Air delivery is quicker as it bypasses the upper airway. For partial stomas, assess if air escapes through the mouth/nose. Breathing too fast (hyperventilation) or too slow (hypoventilation) can be detrimental. A rescue pod, though no longer common, offered a blinking light to guide ventilation timing. Adult ventilation rate is 10-12 breaths per minute (every 5-6 seconds), while for children it's faster (every 3-5 seconds). Gentle, smooth squeezes of the BVM are important to avoid lung damage or gastric distension.

Oxygen is a drug and must be administered judiciously. Too much oxygen can cause harm, especially in patients with heart attack or stroke. Oxygen protocols allow for standing orders, but EMTs must assess patient needs. Equipment must be safe, lightweight, portable, and dependable. Oxygen cylinders (D, E, M tanks) come in various sizes and are typically steel or aluminum alloy. Medical-grade oxygen tanks are green or green with white. Essential safety measures include using appropriate pressure gauges and wrenches, ensuring good gaskets, opening valves fully, keeping tanks cool, ventilated, and secured (never standing upright), and regular hydrostatic testing. Avoid grease, oil, fat-based soaps, adhesive tape, and dragging tanks. Never smoke around oxygen.

Over-oxygenation can be harmful, particularly for patients with a hypoxic drive or premature infants (risk of blindness). Long transport times require careful oxygen management. Underlying medical conditions like myocardial infarction and stroke necessitate cautious assessment of oxygen needs. Various oxygen administration tools exist, including nasal cannulas (2-4 L/min, 24-44% O2), non-rebreather masks (15 L/min, 80-90% O2) for high flow needs in breathing patients, partial rebreathers (40-60% O2) which are less common, and Venturi masks for precise oxygen concentration delivery (common for COPD patients). Trach masks are used for patients with tracheostomies.

Special considerations include managing facial injuries (secure airway, suction fluids), airway obstructions (abdominal/chest thrusts, finger sweeps), and dentures (remove if hazardous). For children, large tongues are a concern, and the trachea is flexible, requiring neutral head positioning. Children burn oxygen faster and need more frequent ventilations. Flow-restricted oxygen-powered ventilatory devices (demand valves) are powerful but not suitable for children due to high pressure. When paramedics place an advanced airway, EMTs assist by putting the patient in a 'sniffing position,' ensuring pre-oxygenation, and potentially applying cricoid pressure ('burping the patient'). After intubation, the tube must be secured, and lung sounds assessed to confirm correct placement (listening for air in lungs, not stomach). If stomach sounds are heard, repositioning the tube is necessary. For trauma patients, maintain cervical spine stabilization during intubation. Recheck tube placement after any patient movement. Never touch a patient or equipment during defibrillation.