Invisible hunger in the Intensive Care Unit: Care strategies and essential considerations

It is widely recognised that admission to an Intensive Care Unit (ICU) is a devastating event for both the patient and the family.¹ In this context, health professionals focus on crucial aspects to preserve the patient's life. One strategy to improve recovery and outcomes in the ICU is bundle ABCDE, a multicomponent approach that addresses several key areas. This includes “A” to assess, prevent and treat pain; “B” to perform awakening and spontaneous breathing trials; “C” for the choice of analgesia and sedation considering factors such as drug metabolism, dose, titration and interruption; “D” to evaluate, prevent and treat delirium; and E to promote early mobility and exercise.²

Despite this, a recurring unresolved and, in many cases, invisible problem in the ICU is malnutrition, which reaches stands at 38%–78% depending on the country analysed.³ It is presumed that all ICU professionals are fully aware of the high metabolic stress suffered by critically ill patients, requiring nutritional resources to be able to carry out adequate anabolism. However, the question arises: what care should be taken to prevent this malnutrition? Perhaps the first thing that springs to mind are the nutritional recommendations for critical patients, but do we know them and do we know how to apply them appropriately?

The most relevant nutritional recommendations for critical patients in our context are those published by the ESPEN (European Society for Clinical Nutrition and metabolism),⁴ and also those published in the United States by the ASPEN (American Society for Parenteral and Enteral Nutrition).⁵ In addition, we have national recommendations published by the SEMICYUC (Spanish Society of Critical Intensive Medicine and Coronary Units).⁶ When reviewing these guides on the application of nutritional therapy, it is perceived that some recommendations are not entirely concise. Furthermore, although some are supported by a high level of evidence (multicentre experimental studies and meta-analyses), others are based on expert opinions, as well as single-centre observational or experimental studies.

Despite this, there are some key points that we should consider to try to effectively address the problem of malnutrition in the ICU. Among them is the need to carry out a nutritional assessment as soon as the patient is admitted to the unit.^4,6 This will give us an idea of the patient’s needs and decide when and how to start nutritional therapy. So far, so good, but how is this assessment carried out? To facilitate this process, screening scales are used, but within these scales, which one should we use?

There are different tools, SGA (Subjective Global Assessment), NRS-2002 (Nutritional Risk Screening), Nutric (Nutrition Risk in Critically ill) or its modified version m-Nutric. ESPEN states that there is still no gold standard for critically ill patients at risk of malnutrition,⁴ ASPEN recommends NRS-2002 or Nutric.⁵ Some experts find that Nutric is the most suitable for critically ill patients, but it has the drawback of requiring the measurement of Interleukin 6, a parameter that is not usually requested routinely. For this reason, the scale has been modified, creating m-Nutric, which has demonstrated its precision and ease of use.⁷ Despite this, how many nurses consider this nutritional risk in the patient's assessment?

After this evaluation, if the possibility of oral feeding is ruled out and a high risk of malnutrition is identified, nutritional therapy must be initiated, but the question arises as to the route of administration: enteral or parenteral. Considering that all experts advocate the use of the digestive system as the first option, the question arises: when and in what quantity should we start enteral nutrition (EN) in the patient? These questions have been the subject of extensive study in the field of nutrition and metabolism in the ICU. Regarding the beginning, ASPEN and ESPEN,^4,5 indicate that the enteral support must be instituted within the first 48 h, with a grade of recommendation B (meta-analysis, well-conducted and low-risk clinical trials or high-quality systematic reviews based on cohort or case-control studies). It is important to note that these studies do not indicate starting doses.

Regarding the amount of diet to be administered, three large multicentre clinical trials have currently been conducted focusing on the supply of energy during the acute or early phase in the ICU, the first 7 days. The EDEN (2012), PermiT (2015) and TARGET (2020) studies compared trophic (restrictive) doses versus full doses, analysing the effect on mortality, quality of life, disability and activities of daily living. No significant differences were obtained between both administration methods.⁸ This evidence supports the ESPEN recommendation, where the full dose of nutrition must be achieved throughout the first 3–7 days, with a grade of recommendation A (high-quality, low-bias meta-analysis). Therefore, trophic feeding (defined by ESPEN as a contribution between 10−20 kcal/h, equivalent to a bottle of isocaloric enteral nutrition of 500 mL/day), is appropriate during the acute phase, avoiding undernutrition.⁴ At the other extreme is the risk of overfeeding, an important problem that requires monitoring of the patient throughout their clinical stay, evaluating different nutritional meters (phosphorus, potassium, water and nitrogen balance, among others).⁹

An underestimated aspect, which is gaining increasing interest, is the critical role of protein intake. It has not yet been clearly defined “when” and “how much” to administer. While national and international studies support the existence of a decrease in protein intake during clinical care,¹⁰ small-scale experimental studies suggest that a high protein intake in the first days could be beneficial for critically ill patients.¹¹ However, the question arises: What is the optimal amount? ESPEN shows a more restrictive recommendation with 1.3 g/kg ideal body weight/day,⁴ ASPEN proposes providing high doses of protein between 1.2 and 2.0 g/kg of actual body weight per day, being higher in patients with burns⁵ and SEMYCIUC between 1.2 and 1.5 g/kg usual weight/in the initial phase.⁶ But if we are providing less EN in the first few days, should extra protein be added to the diet to reach the recommendation?

Furthermore, regarding long-term nutrition, how is it addressed in those patients whose admission to the ICU extends beyond 7 days? Most studies indicate that energy and protein intake after a week in the ICU is usually limited, contributing to chronic malnutrition. The barriers are multifactorial, with special relevance being the shortage of personnel to carry out nutritional care interventions, as well as the lack of qualifications of professionals. Among the factors related to the patient, diet intolerance stands out. Additionally, the institution itself is identified as a determining component, characterised by the absence of specific nutritional protocols.¹²

Another important question is, do we individualise care based on the patient? Currently there is a trend towards personalised medicine. Different experts affirm that it is necessary to accommodate the needs of each patient and not always work with general recommendations.¹³ ASPEN, ESPEN and SEMICYUC are committed to the use of indirect calorimetry to know the patient's needs at all times.^4–6 But is this carried out? Some studies suggest that in many ICUs a standard of nutrition is prescribed for all patients, regardless of need or weight.¹⁴ The national multicentre study carried out by the MoviPRE team in its nutrition line, demonstrated a negative correlation between obesity and nutrition, with greater weight or less mL of diet provided.¹⁰

Continuing with the above, it is important to highlight that overweight and/or obese patients are increasingly seen in the ICU,⁴ but are they treated in any different way at a nutritional level? The ESPEN recommendations urge special management for this type of individuals, since adipose tissue has a lower metabolic activity to muscle and therefore it must be taken into account that part of the body weight will have a decreased metabolic activity. This concern transcends borders. Analysing a healthcare context that has specialised personnel (nutritionists), a group of Australian researchers concluded that only a little more than 50% of ICU patients follow the specific recommendations related to obesity.¹⁵ The question is, how do we manage this in our environment?

Once it is decided to restart oral feeding, it is of interest to discuss the issue of this transition. The patient has had a tube in the epiglottis for a certain period of time, preventing its function, or even a tracheostomy has been performed, which may result in what is known as “Post-Extubation Dysphagia” (PED) or “Oropharyngeal Dysphagia” (OPD). This is associated with an increased risk of aspiration and pneumonia, delayed resumption of oral intake (which contributes to malnutrition), decreased quality of life, prolonged stay in both the ICU and the hospital, in addition to increased morbidity and mortality. The results of the studies are contradictory and disparate, reporting a prevalence of between 3% and 62%.¹⁶ Furthermore, how many ICUs in Spain have an OPD detection protocol? The scientific community affirms that it is not routinely detected in most ICUs,¹⁷ perhaps due to limited awareness, being a rather poorly recognised problem.

Against this backdrop, what nursing interventions could be performed? Zuercher et al., in a review of the international literature, found proposals for OPD care such as modifying the texture of food, use of dental prostheses, as well as compensatory manoeuvres, such as re-educating the patient to hold their breath while swallowing or cough immediately after swallowing. Are these educational interventions carried out on a daily clinical basis in our context? It is feasible to think that there is a lack of awareness, knowledge and even skills in this regard. Researchers in a Brazilian hospital considered the same thing, in which they designed a clinical trial including a speech therapist in the intervention arm.¹⁸ The results were highly positive, which leads us to think, just as it is necessary to incorporate a physiotherapist into the ICU, could the team be expanded with a speech therapist to support us in this aspect?

Perhaps, although we must continue working on essential key points, such as those related to the ABCDE, we could incorporate the “F” for “Feeding” as a new priority during the admission of patients to the ICU. Although this letter has already been proposed to the family and, without intending to relegate crucial aspects, we could also consider the letter “G”, as symbolising intestinal care, i.e. the gut.

Approaching patients in the ICU involves not only maintaining existing practices but also exploring new avenues that further improve clinical outcomes. The inclusion of the “F” and the “G” in our care strategy could provide a more comprehensive dimension to patient care in the ICU, ensuring not only immediate survival but also a sustainable and complete recovery. This more holistic approach would reflect the continued commitment to excellence in critical patient care.