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Care and Nutrition for Critically Ill Adults

Updated: Jul 6, 2023

Having the right care and nutrition is important, especially when you’re sick or injured. However, different severities of illness do require specific care and nutrition to make sure these individuals are getting the best care possible during their time of need. Being critically ill is serious- it isn’t just something one can recover from with minor treatments. Being critically ill definitely sounds worse than your average illness, but do you really know to what extent? This article will help us to understand what it means to be critically ill and what kind of care and nutrition is necessary for critically ill patients.


It’s important to note that “studies have focused on care provided in hospital locations such as in intensive care or emergency units, which exclude care provided in hospitals lacking such units, and to critically ill patients in general hospital wards” [1]. This isn’t to say that critically ill patients only reside in intensive care units (ICUs), but there just haven’t been enough studies on critically ill patients outside of the ICU. So, since so many studies about critically ill patients focus on ICUs, let’s get into what an ICU is. An ICU is “a hospital unit in which critically ill patients receive intensive and continuous nursing, medical care, and supervision that includes the use of sophisticated monitoring and resuscitative equipment” [2]. ICUs are also referred to as critical care units, which makes sense considering this is where many critically ill patients get their care.


Now that we have that in order, let’s focus on some critical illnesses that patients can be admitted to the ICU for. There are different kinds of critically ill patients that receive different types of critical care. There is adult critical care, pediatric critical care, and neonatal critical care. This article is focusing on adult critical care, so let’s find out what the most common illnesses are for this group of critically ill patients. “Cardiac, respiratory, and neurologic conditions are common in adult ICU patients. The five primary ICU admission diagnoses for adults are respiratory insufficiency/failure with ventilator support, acute myocardial infarction, intracranial hemorrhage or cerebral infarction, percutaneous cardiovascular procedures, and septicemia or severe sepsis without mechanical ventilation” [3]. After we go over what each of these diagnoses means, we can finally get into what care and nutrition looks like for these patients. Respiratory failure is when a patient is having a hard time breathing without support. This condition “develops when the lungs can’t get enough oxygen into the blood” [4]. Acute myocardial infarction is just medical jargon for what most of us would call a heart attack. A heart attack is “a deadly medical emergency where your heart muscle begins to die because it isn’t getting enough blood flow” [5]. A quick restoration of the blood flow is important or else permanent damage may occur. An intracranial hemorrhage is when there is bleeding occurring inside the skull. “The pooling of blood puts pressure on the brain, which can lead to rapid brain damage or death” [6]. Continuing, a cerebral infarction, or ischemic stroke, “occurs as a result of disrupted blood flow to the brain due to problems with the blood vessels that supply it. A lack of adequate blood supply to brain cells deprives them of oxygen and vital nutrients which can cause parts of the brain to die off” [7]. Percutaneous cardiovascular procedures are needed to help unblock coronary arteries to increase blood flow back into the heart [8]. Lastly, septicemia and sepsis are not the same, but they are related. “Septicemia is an infection that occurs when bacteria enter the bloodstream and spread. It can lead to sepsis, the body’s reaction to the infection, which can cause organ damage and even death” [9]. Since we’ve gone over some patient conditions that require critical care, let’s finally get into what care and nutrition looks like for these patients.


As you may have gathered from the information above, “critical care is the process of looking after patients who either suffer from life-threatening conditions or are at risk of developing them” [10]. What exactly goes into this type of care, though? Well, “effective intensive care demands an integrated approach that stretches beyond the boundaries of the ICU. It requires prevention, early warning and response systems, a multidisciplinary approach before and during an ICU stay, as well as comprehensive follow-up or good quality palliative care” [10]. With that being said, let’s go over what effect critical care can look like at its different points. With regards to prevention, of course the goal is for patients to not have to be admitted to the ICU. “Rapid optimization of care on the ward and early senior involvement are essential to minimize any deterioration and reduce the need for subsequent critical care admission” [10]. Making sure patients are getting the care they need before reaching the necessity of critical care is extremely important.

This may seem obvious, but hospitals and other healthcare facilities must have properly trained staff in order to achieve this. So, “medical emergency and critical care outreach teams may play an important role in facilitating early aggressive ward care as well as helping with education and development of skilled ward staff” [10]. When it comes to being admitted into critical care, there are two possibilities. There are planned admissions, and then there are emergency admissions. Planned admissions are for “patients requiring optimization and monitoring of their physiological condition before or usually after an intervention, e.g. the postoperative care of the high-risk major general surgical patient to monitor for complications of the surgical procedure, anaesthetic or exacerbation of known comorbidities” [10]. On the other hand, emergency admissions are for “patients with potential or established organ failure needing monitoring and support of one or more vital organ functions, e.g. a patient with septic shock secondary to four quadrant peritonitis requiring invasive ventilation and haemodynamic support post operatively” [10]. In either case, patients being admitted into critical care require close attention to ensure the best possible outcome for their health.


As for levels of critical care, there are two notable ones which include: care in a high-dependency unit (HDU), or level two care; and care in an intensive care unit, or level three care. Care for patients in an HDU includes [10]:

● respiratory: non-invasive ventilation, arterial blood gases

● cardiovascular: low dose vasopressors, invasive arterial pressure monitoring

● renal: close fluid balance control, certain renal replacement therapies

Care for patients in an ICU includes [10]:

● respiratory: invasive and non-invasive ventilation, extra-corporeal membrane oxygenation (ECMO) or carbon dioxide removal (ECCO2R) in selected centres

● cardiovascular: vasopressor and inotropic support, advanced cardiac output monitoring, intra-aortic balloon pump, ventricular assist devices, ECMO

● renal: renal replacement therapies

● neurological: intracranial pressure monitoring, EEG, advanced neurological monitoring

Like we went over before, Effective critical care doesn’t just happen in the HDU or ICU, so what does post-critical care look like? Well, “many units are developing processes to ensure high-quality in-patient follow-up with some hospitals having established RaCI (Recovery after critical illness) clinics. These may help to understand, alleviate, and prevent the detrimental long-term effects of critical illness” [10]. Following up with critical care patients once they are discharged is extremely important to know how they are coming along and to know if any improvements or changes could be made to help them even more.


As for nutrition in critical care units, “medical nutrition therapy (MNT) is an essential part of the care for critically ill patients'' [11]. Although there is controversy surrounding what kind of nutrition critically ill patients need, making sure patients are getting good nutrients is still a significant part of critical care. “Greater protein and energy intake may be associated with improved mortality in patients at nutritional risk as stated in a recent meta-analysis, but evidence remains controversial” [11]. Of course, more research needs to be done, especially with regards to what nutrition intakes could help or hurt critically ill patients. Furthermore, like every diet, different individuals will need different requirements and a plan that fits them. “Increased protein intake, was associated with improved long-term physical recovery and lower mortality in observational trials,” but “a systematic review and meta-analysis of 14 RCTs did not show any impact of different amounts of protein delivery on outcomes mortality, mechanical ventilation, infections, and length of stay” [11]. Suffice to say, there definitely needs to be more studies on nutrition for critically ill patients.


I know this was a whole bunch of loaded information to take in; some of it may have been new to you, or maybe you already knew a bit about it. Hopefully, this article has helped you to understand a bit more about what it means to be critically ill and what kind of care critically ill patients receive.



1. Kayambankadzanja, R., Schell, C., Wärnberg, M., Tamras, T., Mollazadegan, H., Holmberg, M., Mølsted Alvesson, H., & Baker, T. (2022). Towards Definitions of Critical Illness and Critical Care Using Concept Analysis. MedRxiv.

2. American Psychological Association. (n.d.). Intensive Care Unit. American Psychological Association.

3. Critical Care Statistics. Society of Critical Care Medicine (SCCM). (n.d.).

4. U.S. Department of Health and Human Services. (2022, March 24). What is Respiratory Failure?. National Heart Lung and Blood Institute.,made%20in%20the%20body’s%20cells

5. Heart Attack: Symptoms and Treatment. Cleveland Clinic. (2022, October 30).

8. Percutaneous Coronary Intervention (PCI). Cleveland Clinic. (2021, November 6).  

9. Septicemia (Blood Poisoning): Causes, Management. Cleveland Clinic. (2021b, May 17).

10. Jackson, M., & Cairns, T. (2021). Care of the critically ill patient. Surgery (Oxford, Oxfordshire), 39(1), 29–36.

11. Hill, A., Elke, G., & Weimann, A. (2021). Nutrition in the Intensive Care Unit-A Narrative Review. Nutrients, 13(8), 2851.




Author: Lauryn Agron

Editor: Chadwick Huynh

Health scientist: Chantelle Moore


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