Care of the critically ill patient

Last updated: June 13, 2023

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Summarytoggle arrow icon

Critically ill patients are typically cared for in intensive care units (ICUs), which are designated hospital units dedicated to managing patients who require a higher level of care than that available on a general medical ward or step down unit, staffed by highly trained clinicians. After initial resuscitation and stabilization, management of ICU patients typically involves ongoing hemodynamic monitoring (often via invasive devices such as an arterial line) and respiratory monitoring (including interpretation of ventilator alarms for mechanically ventilated patients), supportive care of the critically ill patient (including nutrition and metabolic support, analgesia, and sedation), and the prevention of common complications (e.g., VTEs, pressure ulcers, nosocomial infections, delirium). Predictive scoring systems (e.g., the SOFA score, APACHE II score) may be useful for the prognostication of ICU patients. Given the critical nature of ICU care, teamwork and communication, and end-of-life care are essential. Typical reasons for admission to an ICU include the need for organ support (e.g., for patients with brain injury, acute coronary syndrome, COPD exacerbation, sepsis, GI bleeding) and/or close, continuous monitoring (e.g., postoperatively or while receiving a high-risk medication).

Definitiontoggle arrow icon

  • Critical illness: a state of poor health with vital organ dysfunction and/or imminent death [2]
  • Critical care: provision of medical care to critically ill patients by supporting vital organ function [2]
  • Intensive care units
    • Units that provide the highest level of care available in a hospital
      • Can be open or closed
      • Can be general medical or surgical, or specialized units (e.g., neurological, cardiac)
    • Indicated for patients who require close or continuous monitoring:
  • Step down units (intermediate care units): units that provide a higher level of care than a general ward but a lower level of care than an ICU

There are no established general criteria for ICU admission. The decision to admit a patient typically relies on the clinical judgment of the physician and the availability of beds and resources.

Resuscitation and stabilizationtoggle arrow icon

The first step in caring for critically ill patients is resuscitation and stabilization. See also “ABCDE approach” for more detail.

Hemodynamic support

Respiratory support

See also “Management of respiratory failure.”

Extracorporeal membrane oxygenation (ECMO)

  • Consider use in patients who require advanced respiratory and/or circulatory support
  • VA-ECMO: provides respiratory and circulatory support
  • VV-ECMO: provides respiratory support only

Monitoring parameterstoggle arrow icon

All critically ill patients require close monitoring of hemodynamic and respiratory status.

Hemodynamic monitoring

Invasive devices

Routine pulmonary artery catheterization for hemodynamic monitoring has not been shown to improve outcomes in critically ill patients with shock and, therefore, should only be used in specific cases. [3][4]

Respiratory monitoring

Consider using the DOTTS mnemonic to remember the interventions in a mechanically ventilated patient who is deteriorating: Disconnect, Oxygenate, assess the Tube position and function, Tweak ventilator settings, and perform a chest Sonogram (e.g., to identify pneumothorax). [5]

Supportive caretoggle arrow icon

Management should be individualized for each patient, but there are some common features of supportive care in critically ill patients.

Critically ill patients need FAST HUGS DAILy: every day, evaluate their Feeding and fluids, Analgesia, Sedation, Thromboembolic prevention, Head of the bed elevation, Ulcer prophylaxis, Glucose control, Skin pressure ulcer prophylaxis, Deescalation of drugs, Assessment of delirium, Indwelling catheters, Last bowel movement. [6]

Nutrition and metabolic support of critically ill patients [6][7][8]

Enteral nutrition is associated with fewer metabolic complications and bloodstream infections and better patient outcomes compared to parenteral nutrition. [6]

Analgesia [10]

Sedation [8][10]

Prevention of complications [6][7][8]

Prevention of complications is paramount to minimizing harm and improving outcomes.

Prevention of complications in ICU patients
Complication Prevention strategy
VTE prophylaxis
Stress ulcer prophylaxis
Decubitus ulcer prophylaxis
Nosocomial infections
Medication adverse effects
ICU-acquired weakness

Prevent delirium in critically ill patients using the ABCDEF bundle: Assessment of pain, Both spontaneous awakening trials and spontaneous breathing trials, Choice of analgesia and sedation, Delirium screening, Early mobilization, Family engagement. [8]

The use of lorazepam or diazepam for sedation may cause iatrogenic propylene glycol poisoning, as both drugs are dissolved in propylene glycol. Midazolam is an alternative benzodiazepine that does not use propylene glycol as a solvent. [15]

Predictive scoring systemstoggle arrow icon

Scoring systems can give a general sense of prognosis but they should not be the sole factor used to determine the level of care required or if a patient should be moved to a lower level of care.

Sequential organ failure assessment score (SOFA score) [16][17]

  • Used in critical care settings as a tool to identify organ failure and predict mortality
  • The score should be calculated 24 hours after ICU admission and then every 48 hours.
  • Commonly used to assess mortality risk in patients with sepsis
SOFA score [16][18]
System 0 points 1 point 2 points 3 points 4 points


PaO2:FiO2 ratio (mm Hg)

  • ≥ 400
  • ≤ 400
  • ≤ 300


Platelets (× 103/mm3)

  • > 150
  • ≤ 150
  • ≤ 100
  • ≤ 50
  • ≤ 20


Bilirubin (mg/dL)

  • < 1.2
  • 1.2–1.9
  • 2.0–5.9
  • 6.0–11.9
  • ≥ 12.0


  • MAP ≥ 70 mm Hg
  • MAP < 70 mm Hg

Central nervous system

Glasgow coma scale score

  • 15
  • 13–14
  • 10–12
  • 6–9
  • < 6

Renal function

Creatinine (mg/dL)

  • < 1.2
  • 1.2–1.9
  • 2.0–3.4
  • 3.5–4.9
  • OR urine output < 500 mL/day
  • ≥ 5.0
  • OR urine output < 200 mL/day


  • SOFA score ≥ 2 points: overall mortality risk ∼ 10%

Acute physiology and chronic health evaluation II (APACHE II score)

The APACHE II score should be calculated within the first 24 hours of ICU admission. [19][20]

  • Components
    • Physiological score
    • Age score
    • Chronic health score
  • Result: an estimate of the patient's in-hospital mortality risk
  • Potential limitations

Additional scoring systems for specific conditions

Commonly used scoring systems for specific conditions include:

End-of-life considerationstoggle arrow icon

End-of-life considerations should be addressed for all patients upon admission to the ICU. Essential tasks include establishing a decision-maker, confirming advance directives, and considering the need for a palliative care consult.

Addressing family and friends after death should be prioritized.

Teamwork and communicationtoggle arrow icon

An essential part of ICU care is ensuring appropriate communication with the following people. See also “Key principles of communication and counseling.”

  • Patients and family:
    • Update the patient's family regularly (by phone if the family are not at the bedside).
    • Communicate in an empathic, patient-centered way.
    • Elicit the patient's and family's needs and wants.
    • See also “Breaking bad news.”
  • Nonphysician team members: See “Communicating with nonphysician team members.”
  • Other physicians
    • Update consultants and other team physicians regularly throughout the day.
    • If a patient begins to deteriorate, do not hesitate to request help immediately.
    • Ensure you provide a focused and constructive signout.

Common conditions treated in the ICUtoggle arrow icon

Common ICU conditions by system
System Management
Infectious disease

Management checkliststoggle arrow icon

This section provides checklists for managing the major aspects of patient care over the course of an ICU admission. The following checklists may serve as general guidance but may not be applicable to all patients and/or settings; follow institutional protocols.

Admission checklisttoggle arrow icon

  • Review electronic medical records for the following (before admission if possible):
  • Immediately upon admission:
    • Note current vital signs.
    • Resuscitate and stabilize the patient as necessary.
    • Place any urgent orders.
  • Perform a focused history and examination. If the patient has the capacity:
    • Confirm home medications.
    • Address end-of-life considerations (see “End-of-life considerations” in “General principles of ICU care”).
    • Ask for permission to update a family member and obtain relevant contact information.
  • Place admission orders.
  • Write an admission note and make sure to document the following:
    • General prognostic score (e.g., APACHE II, SOFA score)
    • Scores relevant to the patient's reason for admission (e.g., PSI for pneumonia)
    • Wishes regarding advance directives (and complete any relevant forms)
  • Update family members if appropriate.
  • Update signout template (see “Signout checklist”).

Daily care checklisttoggle arrow icon

Signout checklisttoggle arrow icon

Due to the complexity of ICU patients, a signout template with the following information for each patient is usually maintained and updated daily by each physician. A verbal signout should also be performed, highlighting the most relevant information. It is often helpful to sign out while walking around the unit to briefly check on each patient. The signout should include:

  • Overall status: i.e., unstable, deteriorating, stable, or up for transfer
  • Reason for admission
  • Active issues (e.g., complications) and to-do list
  • Current neurological and mental status
  • Lines, tubes, and catheters
  • Anticipated and potential complications along with contingency plans
  • Code status and advance directives
  • Contact information for the patient's family

Transfer/discharge checklisttoggle arrow icon

Patients are usually transferred to the general medical floor before being discharged, but some patients may be discharged directly from the ICU or cardiac intensive care unit.

  • Begin planning for transfer or discharge.
  • Begin ventilator weaning when the patient meets the criteria.
  • Deescalate medications (e.g., pressors, sedatives) and IV fluids as appropriate.
  • Convert medications from IV to PO form.
  • Advance the patient's diet.
  • Perform medication reconciliation.
  • Write a transfer note (this should be similar to a discharge summary).
  • Provide a verbal signout to the accepting service.
  • Update the patient's family as appropriate.

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Referencestoggle arrow icon

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  2. Nair AS, Naik VM, Rayani BK. FAST HUGS BID: Modified Mnemonic for Surgical Patient.. Indian J Crit Care Med. 2017; 21 (10): p.713-714.doi: 10.4103/ijccm.IJCCM_289_17 . | Open in Read by QxMD
  3. Marra A, Ely EW, Pandharipande PP, Patel MB. The ABCDEF Bundle in Critical Care. Crit Care Clin. 2017; 33 (2): p.225-243.doi: 10.1016/j.ccc.2016.12.005 . | Open in Read by QxMD
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  8. Consortium for Spinal Cord Medicine.. Early acute management in adults with spinal cord injury: A clinical practice guideline for health-care professionals.. J Spinal Cord Med. 2008; 31 (4): p.403-79.
  9. Bansal C, Scott R, Stewart D, Cockerell CJ. Decubitus ulcers: A review of the literature. Int J Dermatol. 2005; 44 (10): p.805-810.doi: 10.1111/j.1365-4632.2005.02636.x . | Open in Read by QxMD
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  12. Rhodes A, Evans LE, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016. Intensive Care Med.. 2017; 43 (3): p.304-377.doi: 10.1007/s00134-017-4683-6 . | Open in Read by QxMD
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  16. Towards definitions of critical illness and critical care using concept analysis. Updated: January 10, 2022. Accessed: July 6, 2022.
  17. $Contributor Disclosures - Care of the critically ill patient. All of the relevant financial relationships listed for the following individuals have been mitigated: Alexandra Willis (copyeditor, was previously employed by OPEN Health Communications). None of the other individuals in control of the content for this article reported relevant financial relationships with ineligible companies. For details, please review our full conflict of interest (COI) policy:.
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