The Most Common ICU Admission Diagnosis: A Nurse’s Guide

by | Sep 14, 2023 | Critical Care | 1 comment

After spending some time in an ICU, you start to encounter the same types of patients repeatedly. Instead of only sharing the most common ICU admission diagnosis (as that’s hard to definitively say), we’ve compiled the top nine diagnoses you’ll encounter in the ICU, so you can walk in on day one already well-versed.

Within this extensive guide, we will explore the pathophysiology, typical complications, associated risk factors, prognoses, and top-priority nursing considerations for these critical conditions. Together, let’s arm ourselves with knowledge and compassion to deliver the best possible care for our patients.

most common icu admission diagnosis with freshrn leaf

Common ICU Admission Diagnoses

We will discuss the top nine ICU admission diagnoses, but you may see others more frequently. You will notice we did not include myocardial infarction or stroke, as these are often sent to a cardiovascular intensive care unit or a neuro intensive care unit, respectively.

Sepsis and Septic Shock

Pathophysiology: Sepsis arises from the body’s overwhelming response to infection, leading to systemic inflammation, impaired microcirculation, and organ dysfunction.

Common Complications: Multi-organ failure, disseminated intravascular coagulation (DIC), acute respiratory distress syndrome (ARDS).

Higher Risk Individuals: Immunocompromised patients, elderly, those with chronic illnesses.

Prognosis: Early recognition and intervention are crucial for survival. Mortality rates decrease significantly with prompt treatment.

Nursing Considerations: Vigilant assessment for signs of sepsis for early detection, close monitoring of vital signs with prompt intervention, administering antibiotics on time, and providing supportive care.

Sepsis has a spectrum of severity, with the most critically ill patients receiving care in the ICU. Septic patients in the ICU could need just a little blood pressure support but are doing well otherwise, or could be suffering from multi-organ system failure and subsequently receiving end of life care – and everything in between.

Once sepsis is identified, implementing interventions within the first hour is imperative. The golden triad of sepsis care includes:

  • Drawing labs ASAP (specifically blood cultures, lactate, CBC w/diff)
  • Fluid resuscitation (and if fluid doesn’t fix the hypotension, then it’s on to vasopressors!)
  • Starting antibiotics (after blood cultures are drawn; broad spectrum given immediately, then further changed to be more specific when more information is available)

Your hospital probably has a sepsis protocol for nurses to follow that includes the interventions previously mentioned. You may also draw other labs like procalcitonin, which helps determine the severity and guide antibiotic use, or obtain imaging like a CT scan and/or x-ray.

Patients may require intubation to maintain their airway. In which case, they would likely also need sedation.

Acute Respiratory Distress Syndrome (ARDS)

Pathophysiology: ARDS is a severe lung condition characterized by widespread inflammation in the lungs, leading to fluid buildup in the alveoli. This impairs oxygen exchange, causing severe respiratory distress.

Common Complications: Pneumothorax, secondary infections, pulmonary fibrosis, barotrauma.

Higher Risk Individuals: Those with severe lung injuries, pneumonia, sepsis, or those who have undergone major surgeries.

Prognosis: Prognosis depends on the underlying cause and the patient’s overall health. Early intervention and supportive care can improve outcomes.

Nursing Considerations: Close monitoring of oxygen levels, ventilator settings, and lung compliance. Administering oxygen and managing mechanical ventilation. Preventing complications like infections or barotrauma.

Patients with severe ARDS are quite sick and may even be a 1-to-1. (This means that they have a dedicated nurse, rather than the typical ICU nurse who is caring for two patients.) The lungs of ARDS patients tend to follow a similar clinical course that begins with hypoxemia that requires high concentrations of inspired oxygen and PEEP. This can progress to severe hypoxemia.

This can then result in persistent and severe hypoxemia which makes the patient ventilator-dependent and is considered the fibroproliferative phase. Those that survive this can then enter a phase of resolution and repair, which can last weeks to months. Nosocomial infections are common due to the severity of the disease process and prolonged periods of time on the ventilator and other invasive equipment.

You will be working closely with respiratory therapy in caring for an ARDS patient. There will likely be frequent interventions like ABG draws, changes in ventilator settings, and even proning. Severe ARDS requires serious interventions like pulmonary vasodilators, nitric oxide, and ECMO.

Delirium is a major concern for these patients, as they are often sedated for long periods of time and the more severe cases receive paralytics.


Pathophysiology: Pneumonia is an infection of the lung tissue, which leads to inflammation, consolidation, and impaired gas exchange.

Common Complications: Pleural effusion, abscess formation, sepsis, respiratory failure.

Higher Risk Individuals: Elderly, immunocompromised individuals, those with chronic respiratory conditions.

Prognosis: Prognosis varies depending on the type of pneumonia, the causative agent, and the overall health of the patient. Timely treatment improves outcomes.

Nursing Considerations: Monitoring vital signs, oxygen levels, and respiratory status. Administering antibiotics as prescribed. Providing respiratory support and promoting airway clearance.

As an ICU nurse, you will care for many pneumonia patients. If there was a top runner for the most common ICU admission diagnosis, it’s pneumonia. Some may require minimal respiratory support, while others may need ventilator support. Patients suffering from pneumonia often need a bronchoscopy, which is a bedside procedure that the primary nurse assists with. This enables the physician to obtain a sputum sample to help diagnose the specific pathogen causing the issue (and thus enabling better antibiotic selection, if it is bacterial in nature), get a good look into the patient’s lungs, and remove some secretions.

Acute Kidney Injury (AKI)

Pathophysiology: AKI results from a sudden decrease in kidney function, leading to a buildup of waste products and electrolyte imbalances.

Common Complications: Fluid overload, electrolyte abnormalities, metabolic acidosis, uremia.

Higher Risk Individuals: Those with pre-existing kidney disease, heart failure, sepsis, or those on nephrotoxic medications.

Prognosis: Prognosis depends on the cause and severity of AKI. Early intervention and management can improve kidney function.

Nursing Considerations: Monitoring fluid balance, electrolyte levels, and kidney function. Administering medications cautiously to prevent further damage. Implementing measures to prevent complications.

There are three types of renal injury: pre-renal, intrinsic (intra-renal), and post-renal. The management depends on identifying the cause, treating reversible causes (hypotension, for example), discontinuing/adjusting and preventing anything actively causing new injury (eliminating meds that are particularly hard on the kidneys or changing dosing, for example), and identifying and treating any complications.

Many patients are on peritoneal or hemodialysis at home, and therefore any additional injury can be devastating. For example, a patient with chronic renal failure gets into a car accident and has internal injuries causing hypotension. Someone without baseline renal failure may be able to compensate with minimal support, but if the patient is already dealing with poor kidney function at baseline, that can make it significantly worse, and recovery that much more challenging.

Gastrointestinal Bleeding or Perforation

Pathophysiology: Gastrointestinal bleeding or perforation occurs when there is a breach in the lining of the gastrointestinal tract, often due to ulcers, trauma, or vascular abnormalities.

Common Complications: Hemorrhagic shock, peritonitis, sepsis, anemia.

Higher Risk Individuals: Those with a history of gastrointestinal ulcers, on certain medications (e.g., NSAIDs), or with underlying vascular conditions.

Prognosis: Prognosis depends on the severity and location of the bleeding or perforation. Prompt intervention is crucial for favorable outcomes.

Nursing Considerations: Monitoring vital signs, assessing for signs of bleeding or peritonitis, administering blood products or medications to stop bleeding.

Once you smell a GI bleed, you’ll never forget it.

Nurse tip: Do what you can to keep the smell tolerable for the patient. That may mean putting coffee grounds in a basin or getting a continuous deodorizer in the room.

These patients will likely require repeated blood transfusions and endoscopies to assess the situation and intervene as much as possible. Be sure to watch for blood transfusion reactions.

Acute Pancreatitis

Pathophysiology: Acute pancreatitis is characterized by inflammation of the pancreas, often due to gallstones, alcohol abuse, or certain medications. This leads to enzyme leakage and autodigestion of the pancreas.

Common Complications: Pancreatic abscess, pseudocyst formation, multi-organ failure.

Higher Risk Individuals: Those with a history of gallstones, alcohol abuse, or certain medications.

Prognosis: Prognosis depends on the severity of pancreatitis and the underlying cause. Early intervention and supportive care are essential.

Nursing Considerations: Monitoring vital signs, pain assessment, strict fasting, administering medications, and providing nutritional support as indicated.

This is one of the most painful disease processes someone can deal with in the hospital. You must ensure the patient has adequate pain management. Remember, sedation is not pain control. Therefore, if you have a patient who is intubated and sedated with Propofol only, they are not receiving any pain medication.

Fluid replacement, pain control, nutrition, close monitoring, and the management of underlying predisposing conditions and complications is the focus.


Pathophysiology: Trauma encompasses a wide range of injuries resulting from accidents, falls, or intentional harm. Severity and type of injuries vary widely.

Common Complications: Hemorrhage, organ failure, sepsis, post-traumatic stress disorder (PTSD).

Higher Risk Individuals: Anyone can be at risk for trauma, but individuals in high-risk occupations or those engaged in risky activities are more susceptible.

Prognosis: Prognosis varies greatly depending on the type and severity of injuries. Prompt and appropriate treatment is critical for positive outcomes.

Nursing Considerations: Assessing and managing injuries, monitoring for signs of complications, providing pain relief, and addressing psychological support for trauma patients.

This is another top runner for most common ICU admission diagnosis. And patients admitted to the ICU for trauma can be exceedingly complex. Often, these patients were fine one moment, and the next moment they were in a motor vehicle accident. Types of trauma you could encounter as an ICU nurse include:

  • Head, neck and spine trauma
  • Chest trauma
  • Abdominal and pelvic
  • Extremity trauma
  • Geriatric or pregnancy trauma

If you work in a trauma center, you may have a dedicated trauma ICU. If you do not work in a trauma setting, you likely will not see this as much. This is because if there are two or more hospitals in your area and one hospital specializes in trauma care, trauma patients will be taken there as a priority.

Trauma patients will be evaluated in the emergency department, stabilized as much as possible, then transferred to the ICU (provided they require ICU-level of care). Many diagnostics will occur to assess the full extent of the damage. This can include CT, MRI, labs, ultrasound, x-rays, and more.

Acute Heart Failure

Pathophysiology: Acute heart failure is a sudden deterioration of the heart’s ability to pump blood effectively, often due to conditions like cardiomyopathy, valvular disorders, or severe hypertension.

Common Complications: Pulmonary edema, cardiogenic shock, renal failure.

Higher Risk Individuals: Those with pre-existing heart conditions, uncontrolled hypertension, or a history of heart attacks.

Prognosis: Prognosis varies based on the underlying cause and the patient’s overall health. Prompt intervention and appropriate management are crucial.

Nursing Considerations: Monitoring vital signs, assessing heart function, administering medications (e.g., diuretics, inotropes), and providing supportive care for heart failure patients.

Managing heart failure is challenging because these patients cannot handle much fluid at all.

Your patient may be dealing with an acute exacerbation of heart failure and that is their primary reason for admission, or they may have heart failure at baseline and are being admitted for something else but their heart failure became increasingly difficult to manage.

The ultimate goal is to reduce preload and afterload. We want the heart to do as little work as possible when it is under such stress, so we use medications to offload the work of the heart onto the meds. Because of this, your heart failure patient may be on many medications to manage the condition, with dosing that changes frequently.

Most Common ICU Admission Diagnosis: Final Thoughts

As an ICU nurse, you will become extremely familiar with these disease processes. While the ICU is intimidating, you will become an expert on the common ICU diagnoses because only certain situations will necessitate an admission to an ICU. Therefore, as you encounter patients with these specific problems, take note of how your institution handles these situations, the order sets and protocols involved, common challenges and obstacles, and more. Take note of it in your device so you refer to it, edit and update it, and review as necessary.

Nurse Tip: If you have an iPhone, create a note for each disease process you encounter frequently and then categorize it with a hashtag. For example #work #ICU #ICUdiagnosis or something like that. On your Notes app, you can search notes by hashtag for quick navigation. If you get a patient with that diagnosis, you can do a quick review to brush-up at the beginning of the shift!

The Ultimate Resource for New ICU Nurses

Trying to build your confidence as a new ICU nurse?

Computer With Course Cover1

Breakthrough ICU from FreshRN is a 6-week, online course specifically crafted for brand new ICU nurses who want to get ahead of the game. So that instead of merely surviving orientation, they’re confidently thriving all the way through. With Breakthrough ICU, it’s like we took all of the highlighted info from the nursing textbooks, mixed in our own experience, wisdom, and expertise, and packaged it in a way that it’s tangible, easy to digest and understand, and can be applied to your very next shift. You can start your ICU journey with your head held high (but not too high!) and your heart calm. 

More Resources for New ICU Nurses


Picture of Kati Kleber, founder of FRESHRN

Hi, I’m Kati.

Kati Kleber, MSN RN is a nurse educator, author, national speaker, host of the FreshRN® Podcast, and owner of FreshRN® – an online platform created to educate, encourage, and motivate newly licensed nurses in innovative ways.

Connect with her on YouTube, Pinterest, TikTok, Instagram, and Facebook, and sign-up for her free email newsletter for new nurses.

1 Comment

  1. Ayantu Gerema



Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.