A beginner’s guide to the ICU

Newcomers to the ICU are often overwhelmed by the sheer volume of unique situations encountered among critically ill patients. Over time, they develop a basic approach and knee-jerk response to most of them — and with even more time, they acquire a more flexible and evidence-based understanding of each situation. However, particularly for residents and students rotating for only a few weeks at a time, it’s helpful to have a “cheat sheet” of basic heuristics.

Here are some simple suggestions for commonly-encountered issues. It must be noted that these are simplifications, and each has exceptions for which it is the wrong answer. This is a starting point only; step one is learning these solutions, but step two is learning when they fail.

With that being said, there are plenty of complicated things in medicine; don’t make the simple things complicated. What follows are some simple things.


The patient is hypotensive. Should you bolus fluid?

Whole books have been written on the question of “fluid responsiveness.” If you stick with this business long enough, you’ll eventually find methods that work for you. Until then, try a small bolus, given quickly, and see if the patient responds. If not, stop doing that.

The patient is out of shock and getting better. They look like the Michelin Man. What should you do?

Diurese them. Eventually they’ll pee it off (if their kidneys work), but they’ve got stuff to do and so do you, so hasten the process. Start with 20mg of IV furosemide, increase the dose if they don’t respond within a few hours, and repeat when the effect wanes until they reach euvolemia.

Does the patient need maintenance IV fluid?

Eh. If you went nuts with their initial resuscitation, probably not. If you’ve kept them very dry, maybe a little. If they’re euvolemic and won’t be able to eat for a long time, fine.

What about albumin?

If you want to bolus but want to limit the total amount of fluid you give, fine. If you think they’re intravascularly dry but whole-body overloaded (e.g. attempts at diuresis result in hypotension, but they’re still edematous), you can try hypertonic albumin combined with diuresis. Be aware that this is all voodoo and probably doesn’t work.

Acceptable numbers

When is hypertension a problem in the routine ICU patient?

Almost never. Keeping the systolic <180 is a reasonable line to draw. Of course exceptions exist, such as neuro patients and those at risk for bleeding.

When is hypotension a problem in the routine ICU patient?

Keep the MAP >65.

When is hyperglycemia a problem in the routine ICU patient?

Keep the blood glucose <180.

When is fever a problem in the routine ICU patient?

Fever may indicate infection and often warrants cultures and some thought about potential sources. The temperature itself, however, is not bad and is mostly a nuisance.

Treat it as a subjective phenomenon, like pain: if it’s bothering the patient, consider acetaminophen or external cooling. Otherwise, who cares.


When should you remove a central line?

As soon as it’s no longer needed and the odds of needing it again are low. Don’t routinely change them out, unless it was not placed in a sterile fashion (emergent lines), in which case remove them ASAP. Femoral lines in most centers are also removed within a few days.

“I can’t aspirate one of the ports on this central line, but it flushes fine.”

A fibrin sheath or small clot is probably creating a one-way valve at the tip. Don’t worry about it. In terribly rare cases the catheter tip could be somewhere bad (extravascular); take an xray if in doubt.

“I can’t aspirate blood from this arterial line, and the tracing is really damped.”

Same problem, a common occurrence in radial lines. Pull it out, and if still needed, replace it. Rewiring it rarely works.

“One of the ports in this line won’t flush.”

It’s clotted. Instill tPA (packaged for this purpose and called “Cathflo”), let it dwell, and then aspirate it back out. Nursing knows how to do this.


Ventilator is “losing volume,” i.e. exhaling substantially less air with each breath than was inhaled.

AKA a “cuff leak.”

Involve respiratory therapy. If minor, add a bit of air to the cuff, and take a chest xray: the tube may be high. If major and the patient is destabilizing, treat as an emergency: pull the tube and reintubate.

The patient occasionally has a paroxysm of movement, and the ventilator’s “high peak pressure” alarm sounds.

They’re coughing. Suction their tube.

The patient is tachypneic, restless, and repeatedly bucking and sounding high pressure alarms.

They are “dyssynchronous.” In order:

  1. Ask if they are in pain.
  2. See if there is anything else making them uncomfortable.
  3. Collaborate with respiratory therapy to adjust the vent to improve their comfort.
  4. Sedate them.

The patient is precipitously desaturating or having other sudden respiratory deterioriation on the vent.

With the help of respiratory therapy, disconnect the vent and bag the patient. Call everyone.

A tracheostomy came out.

If >1 week old, consider carefully replacing it. If <1 week old, don’t stick it back in; get help. (It probably won’t go where you want.) If the patient is doing poorly, just reintubate from above.

The most common reason to intubate someone?

They look terrible.

What should you do immediately after intubation?

Order a chest xray, a blood gas, and an analgesia/sedation package. Remember they may still be paralyzed, yet your RSI sedative may be wearing off, and awake paralysis is never acceptable for even a short time.

What should you do immediately after extubation?

Order pulmonary toilet stuff, discontinue continuous IV sedatives (fentanyl, propofol, benzos, etc), and consider ordering either a diet or a swallow study.

What exactly is “pulmonary toilet”?

The process of clearing secretions from the lungs. Often a problem in weak patients with a poor cough reflex, in trauma patients with chest wall injury (hurts to cough), and in anyone who is bedbound. Manage pain aggressively in trauma patients, such as with PCAs and lidocaine patches. Other than that, in order of aggressiveness, use:

  1. Incentive spirometry, mobilizing out of bed
  2. Flutter valve
  3. Chest physiotherapy (thumping on their chest)
  4. Positive pressure and oscillatory therapies [where available]
  5. Nasotracheal suctioning
  6. Bronchoscopy

Give high-risk admissions and recently-extubated patients the “pulmonary toilet” speech:

Your job now is going to be to use your lungs: take deep breaths, cough out any junk you have in there, and do breathing exercises. Healthy lungs are filled with air and nothing else, but they only stay healthy if you use them. If you take small breaths and don’t cough stuff out, you’re going to get complications like pneumonia. We’ll manage your pain and try to help you out, but using your lungs is your job.

Daily workflow

What should you order every day?

Depends on your unit culture and policy. Common daily labs may include a chemistry, CBC, serum magnesium, and serum phosphorous. Vented patients may have a daily blood gas and xray. When in doubt, order away, but don’t order something you don’t need.

Should you order that CT scan, MRI, or other study requiring travel outside the unit?

Only if it’s going to change your care and is worth the risk. Bad things happen and people can die in Radiology. Especially in MRI. When in doubt, personally go with them.

What are the most common things you’re looking for on routine xrays?

ET tube position, volume status, and focal infiltrates.

Less often: pleural effusions, pneumothorax, other hardware.

How should you organize presentations, notes, and general plans of care?

By system.

What should you ask every day when rounding on a patient no longer being actively resuscitated?

What meds, labs, and other orders can you discontinue? What devices can you remove? Can the patient mobilize? Can they be downgraded from the ICU?

A nurse needs something you find frivolous. Can you act annoyed?

Absolutely not. The next time they may not tell you when a patient is crashing.

A nurse calls because a patient is hypotensive, desaturating, or their airway is causing trouble. You should…

Go there. Now. Physically.

When should you involve someone senior to you in a decision?

  1. When you’re unsure (this depends on you).
  2. When they would expect it (this depends on them).

When should you arrive for your shift?

Early enough that you’ll know each of your patients sufficiently well to understand what’s happening if they code one minute after your shift begins.

When should you leave?

Once you finish all the tasks that would suffer or be delayed from being handed off.

What’s the most important message to convey when you arrive at a code, rapid response, or other emergency?

You’re here. The emergency is over.

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