Clinical Pearls: Evaluating For Intubation

When is it time to say it’s time? I think back on the really bad days of the pandemic when I walked from room to room asking myself this question repeatedly. Honestly, for intensive care unit level covid that’s what it felt like - a few random meds that typically didn’t help, supportive care, and careful vigilance for when it was time to go on the dreaded vent. Our patients feared it, our families feared it; it was the elephant in the room every time you walked in. Outside of covid pneumonia, there are a million reasons why a patient needs mechanical vent support and failing lungs are just one component. This is a very common question I get asked when I am training a nurse practitioner student Here’s how I approach evaluating a patient for intubation need.

Let’s break it down by organ system.

Brain

A multitude of derangements can lead to an impaired neurological impulse to breathe. It could be acute (delirium) or acute on chronic (dementia) and includes many etiologies listed below. Not all of these will impair the respiratory system but can cause altered GCS, which in conjunction with a pulmonary problem could tip them over the scales. The bottom line is, will the patient protect their airway or is there a threat of reduced airway protection? Careful evaluation of the GCS and prediction for ongoing neural-respiratory drive function is key. Sometimes this is clear and sometimes this rides a fine line. Use your assessment of how robust the neurological system is and add this to the other components to obtain a clear picture.

• Respiratory reasons a patient may have altered mental status: hypoxia, hypercarbia.

• Hemodynamic reasons a patient may not be getting brain perfusion: hypotension, cardiac arrhythmia, high ICP 2/2 stroke/lesion/TBI.

• Drug induced: any acute intoxication really but big offenders are ETOH, opioids, heroin, benzos, barbituates, sleep aids…

• Sedation: intentional overdose (more concerning drugs are opiates, benzos, gabapentin), polypharmacy + acute issue which tips them over the scale (ex. COPD on multiple benzos and sedating meds), iatrogenic (commonly seen in the pt with agitated delirium who needs sedation like etoh w/d or acute psychiatric issue with agitation or combativeness), post surgery or procedure related.

• Medical issues: hyper or hypoglycemia, infection, sepsis, high ammonia level, hypothyroid issues, wernicke’s encephalopathy, certain cancers esp neuroendocrine.

• Direct neurological injury: ICH, SAH, space occupying lesion, seizure, CNS infections.

Pulmonary

It is important that you are able to get a pretty good handle on whats going on with the lungs. It can often be the deciding factor in whether or not it’s time to put them on the vent. I’ve lumped non lung issues into this section - problems with restrictive disease, problems with the airways or access to the airway. These are all on a spectrum of mild and not causing major issues to catastrophic. For example, pleural effusions in and of themselves may not lead to respiratory failure unless it is severe and you are unable to alleviate in other manners.

Neuromuscular/chest wall/anatomical issues of the upper airway: GBS, myasthenia gravis, critical illness myopathy, scoliosis, severe kyphosis, ALS, hypophosphatemia, facial trauma, angioedema, tracheomalacia.

Bronchial issue: lesions, mucous plugs (you’ll likely see atelectasis on CXR), trauma, asthma.

Lung issue: pneumonia, pulmonary edema, pleural effusions, atelectasis, COPD, pneumothorax, hemothorax.

Highly advise you watch the TT I’ve attached below which offers a systematic approach to evaluating all the ways the lungs can fail.

Hemodynamic Instability

Includes pulmonary embolus, pulmonary hypertension, cardiac arrest, severe shock of any type, MI, HF, and significant arrhythmia. The problem here is not a ventilatory one but an oxygen delivery and over extraction demand that exceeds the body’s ability to oxygenate.

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1. The first step is to evaluate all your diagnostics to tell you how urgent the issue is and it begins with identifying the problem. Common labs/exam findings/tools I use to help put it all together include:

   • Factors indicating pneumonia

   • CXR/CT

   • ABG (do not rely on this - exam tells you as much or more than an ABG about intubation need)

   • Volume assessment

   • Neuro assessment (including GCS, drooling, have they been aspirating)

   • Echo

   • Lung sounds

   • Respiratory pattern indicating fatigue or high work of breathing: tripoding, abdominal accessory muscle use, pursed lip breathing, unable to speak in full sentences, tachypnea, cyanosis, shoulder shrugging, sighing, nasal flaring, retractions, diaphoresis/clammy, anytime they tell you “I’m tired” while exhibiting any of these signs

   • Respiratory pattern indicating ineffective ventilation: agonal rate, apnea, minimal chest wall movement

   • Respiratory pattern indicating hypoxia: cyanosis, “air hunger” (head bobbing, shoulder shrugging), stridor, grunting, cold extremities

   2. Now that you have your likely diagnosis (IRL it tends to be a multitude of factors), decide if there are temporizing measures you can put in to place to defer or avoid intubation and this is specific to the diagnosis. For example, if it is poor GCS in the setting of over-sedation, can you administer reversal agents, do obnoxious things to keep them awake (fun fact: turn the bed on to continuous CPT), place a nasal trumpet, etc. If it is HF with pulmonary edema can you diurese them, add an agent to reduce afterload or add an inotrope and rapidly address the HF? These population of folks can sometimes respond very well to NIPPV as it can increase intrathoracic pressure (reduce preload) and apply some PEEP. If it’s severe agitated delirium can you start precedex and add CPAP? Conversely a problem that does not have a rapid correction strategy like severe pneumonia or neuromuscular disease like GBS won’t get much benefit from short term bipap. Also consider the long term type of patient like advanced dementia with recurrent aspiration pneumonitis and poor airway control - you should talk prognosis as short term intubation isn’t going to help.

   3. Decide timing for intubation. Is this emergent, urgent, or tenuous with careful vigilence. I can’t really give you a definitive way to approach this. It really just comes down to gestalt. The more experience you obtain the easier it will be to identify. Eventually you’ll get to a point that you can make an assessment in a few minutes. I try to avoid intubation unless necessary, but what defines necessary? That’s the grey zone. There is generally one patient on the census that gets the sign out “probably close to intubation” and we just play pass the buck until they declare themselves one way or the other.

   4. Designation of intubation status. Call me controlling, but I prefer to be the one discussing the indications for intubation and prognosis for recovery. Getting to the best decision for this specific patient depends on supplying the pt/family with the appropriate information. I find sometimes that non-ICU providers may rush the decision or word things in such a way that the decision is made in the heat of the moment without factoring in all the variables.

Click the image above to see the TT about evaluating all the ways the lungs can fail.