Methods to optimize patient outcomes
As EMS providers, we’re commonly called upon to transport the critically ill or injured intubated patient. It’s easy to focus on the intubation procedure, but pre- and post-intubation management are just as important.
What we do before the actual act of intubation, resuscitation, pre-oxygenation really matters. The initial management of these patients can have a significant impact on both their hospital stay as well as their eventual outcome.That’s why the best post-intubation management should always begin with a solid sedation and analgesic package.
From the patient’s perspective, having a large piece of plastic in their throat can be psychologically & physically painful.
Sedation & Analgesia
From the patient’s perspective, having a large, inflated piece of plastic in their throat can be psychologically uncomfortable and physically painful. Our natural means of breathing is via negative pressure ventilation through chest wall and diaphragmatic expansion.
As EMS providers, however, we deliver ventilation to our patients via positive pressure ventilation. Positive pressure ventilation is anything but natural, and it can be unsettling to the conscious or under-sedated patient.
Providing an excellent sedation and analgesic package helps accommodate both the painful presence of an endotracheal tube as well as the fundamental change in the natural way of breathing. In other words, it makes our patients more comfortably compliant with our interventions and therapeutics.
Whether before rapid sequence intubation (RSI) or after the patient has been intubated, paralytics should never be used as a substitute for sedation and analgesia. This isn’t to say that there aren’t instances when reparalyzation is necessary, but it should never done without adequate sedation and analgesia first.1
When making a choice for both analgesics and sedatives, one should be guided by the patient’s clinical condition and anticipated clinical course. An understanding of each medication in your arsenal is critical when making your selection. Keep in mind which drug was initially used for sedation in the setting of RSI.
Drugs such as etomidate are limited to a single dose and often wear off much faster than a paralytic.2,3 Agents such as ketamine and midazolam (Versed) can be used for both induction and continuous sedation.
Presently, the only drug in our modern formulary that provides both sedation and analgesia is ketamine.4 Medications such as propofol, lorazepam (Ativan) and midazolam, although good sedatives, provide no analgesic effect.
It’s also important to note that the use of most sedatives and analgesics carry with them a risk of hypotension. In the already hypotensive patient, it becomes even more important that we begin resuscitation early with fluids, vasopressors or a combination of both, to avoid further drops in blood pressure.
After selecting the desired sedative and analgesic for our patient, the next consideration is the delivery method. First, medications should be given by appropriate weight-based bolus dosing (which may need to be reduced in certain clinical conditions).
Once a desired state of sedation and analgesia is achieved with bolus dosing (i.e., breakthrough dosing) we then follow up with infusions of both—ideally on a pump to avoid the peaks and troughs of inconsistent administration. Any continuous drip is far less effective if not preceded by a bolus of the medication to provide that breakthrough sedation or analgesia.
In some instances, we might receive a patient already on drips for sedation and/or
analgesia, but when transitioning them through the critical care transport world, it’s not unusual or uncalled for to titrate those drips up—accounting for all the stimulation of bouncing down the road or the vibration of a helicopter.
This is often a point of care underappreciated by sending and receiving hospital staff who have never experienced the stressors of the out-of-hospital transport environment and you may want to include this rationale to them when handing over the patient.
It’s important to monitor the usual vital signs, including heart rate, blood pressure, ECG rhythm and pulse oximetry. Other important parameters to monitor are temperature and end-tidal carbon dioxide (EtCO2) with real-time waveform capnography and temperature.
By monitoring capnography, we can ensure the tube remains in the airway as well as effectiveness of ventilation. When comparing pulse oximetry (SpO2) with EtCO2, we can develop a good picture of how well the patient is oxygenating, ventilating and perfusing.
Temperature monitoring is often times overlooked in the prehospital setting, even though it’s much more difficult to regulate environmental temperatures during transport. The critically ill patient has a harder time regulating their own body temperature and is more sensitive to temperature abnormalities.5 As we’re all aware, hypothermia is one of the contributing factors to the lethal triad of shock—alongside acidosis and coagulopathy.6,7
If your transporting intubated patients you will want to utilize a mechanical ventilator. There’s a large amount of evidence that transport of certain patient populations with bag-valve mask (BVM) ventilation leads to worse outcomes.8,9 A ventilator allows us to control consistent oxygenation and ventilation.
The use of a ventilator allows us to target in on settings that allow of euoxemia and eucapnea, as well as continuous monitoring of airway pressures. Since a ventilator gives reliable tidal volumes, we don’t have to worry about over-distention or pressure, as long as the ventilator is set up correctly.
Having a patient on a ventilator also provides monitoring information about the status of the airways and lung compliance.
Often after an RSI, the patient is placed in a supine position. Having them on their back is associated with greater oxygenation and ventilation problems, as well as increased incidence of ventilator-acquired pneumonias. Most intubated patients are better served with their head elevated to at least 30 degrees. By having the head elevated, you can offload pressure the diaphragm, which decreases work of breathing and allows for better expansion of the lungs, especially in the bases.
Ideally, there should be at least two routes of venous access. Having multiple venous access points allows for a backup route should one become removed. With the invention of easy to use intraosseous access this is somewhat less important but still probably best practice.
Other things one should focus on are routinely placing gastric tubes and urinary catheters in intubated patients. Before ever leaving our seat at the patient’s airway, we should make time for placement of a gastric tube.
If prepared beforehand, the placement of a gastric tube is both quick and straightforward, with very little room for complication—provided you’re able to verify placement in a timely manner. The easiest method of confirmation is visually via the laryngoscope; it provides a direct view of esophagus, thereby facilitating placement.
Having this direct path to the GI tract offers us a host of possible benefits, from gastric decontamination, to aspiration prevention, to gastric deflation post-cardiac arrest or RSI after overenthusiastic BVM application. In the latter situation, we can actually see subsequent improvement to ventilation with certain patients.10
By the same token, our patients can benefit from the placement of tube thoracostomies (i.e., chest tube insertion). In the patient with an identified pneumothorax or hemothorax, we can achieve better oxygenation and ventilation by removing both leaking air and/or blood from the pleural space, thus causing the collapse of the lung and loss of available lung tissue to ventilate.
Furthermore, in situations of extremis, auto-transfusion for treatment of the critical multi-trauma patient with a chest tube in place becomes a viable option in the hands of trained providers.11,12
Finally, urinary catheters play an important, though thankless, role in our management of the intubated patient. Perhaps more than any other means, they give us our best look at perfusional changes in the patient suffering from shock.
We’re all familiar with how the body can shunt blood from specific organs and areas in severe states of shock, but after treating for shock, how can we tell if our patients are no longer shunting? One of the best indicators is urine output, measured via Foley with a urometer attached.
The benefits also can extend beyond diagnosis. Relief of a fully distended bladder in the intubated patient can be, at the very least, therapeutic, removing an irritable stimulus during transport and decreasing the need for sedation.
In certain situations, Foley placement can be lifesaving. For the paralyzed patient (usually at T6 and above), a distended bladder can trigger an unbalanced sympathetic overload, leading to an out-of-control hypertensive crisis termed autonomic dysreflexia. The remedy in this situation is a simple one: Remove the noxious stimulus (i.e., bladder distention), and the hypertension resolves.
Blood Pressure & Cardiac Support
When we choose to intubate the critical patient, we are committed to going down a path of positive pressure ventilation (PPV). This change from what is normally negative-pressure ventilation comes with more consequences than simply one of comfort.
Because of pressure gradients that become progressively lower as the blood makes its way back to the heart, blood flows forward through the venous system. By applying positive pressure in the chest, there will be a pressure increase in the central vessels, such as the vena cava. Since this will reduce the pressure gradient there will be a reduction of blood flow to the heart.
This, consequently, leads to a drop in cardiac output, which then gives us lower systolic blood pressures. In some patients, this isn’t something which will concern us. However, there are critically ill patients—such as those who are dependent on preload (i.e., blood returning to the heart)—that are extremely susceptible to the intrathoracic pressure changes produced by positive pressure ventilation (PPV). These patients require hemodynamic support, and this can be done via fluids, blood products and vasopressor agents.
The management of the post-intubated patient is as important as the intubation itself. Often, after the intubation is complete, the EMS provider feels as if their job is done.
However, there are many things left to accomplish in their care. Good post-intubation management is essential to optimize the patient’s outcome. The decisions we make in the management of these patients really do matter.
1. Chong ID, Sandefur BJ, Rimmelin DE, et al. Long-acting neuromuscular paralysis without concurrent sedation in emergency care. Am J Emerg Med. 2014;32(5):452–456.
2. Caro, D. (Mar. 29, 2017.) Induction agents for rapid sequence intubation in adults outside the operating room. UpToDate. Retrieved Feb. 26, 2018, from www.uptodate.com/contents/induction-agents-for-rapid-sequence-intubation-in-adults-outside-the-operating-room.
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