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Introduction

Critical care units initially developed to the fill gaps in healthcare provision for extremely vulnerable patients. In this critically ill cohort are some of the highest dependency patients to be found in hospitals. To support their care, critical care units are intensively staffed with multidisciplinary teams of physicians, surgeons, specialist nurses, physiotherapists, pharmacists, dieticians, enteral and parenteral nutrition support teams, and many other healthcare professionals. Given the severity of the patients’ illness and breadth of cases encountered in critical care, a multidisciplinary team must rapidly and effectively provide the best evidence-based therapies for a plethora of conditions.

Figure 1 is a schematic diagram of the interactions between critical care and the other departments in hospitals that demonstrate the central role of critical care units. Although critical care units can receive referrals from anywhere in any hospital, most admissions to critical care units come from emergency departments, hospital wards, and surgical theaters (see Fig. 2). However, critical care units are not directly involved with patient primary care or with direct discharge from the hospital.

Fig. 1
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The central role of critical care in clinical interface: Admissions to critical care will continuously come from separate and diverse areas of the hospital, most commonly accident and emergency (A&E), surgical theaters, X-rays, and other wards. Critical care discharges will be to wards, theaters, and X-ray. In light of this, critical care wards and staff tend not to interact with primary care or direct discharge out of the hospital (Reproduced with permissions from Menon and Nightingale 2006)

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Fig. 2
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Proportion of admissions to critical care units: Direct admissions represent direct referral from primary care units to critical care units, and indirect admissions include referral to other units prior to admission to critical care (Based on data from Simpson et al. 2005). Proportion of patients referred from “scans” includes those having undergone computed tomography, X-ray scans, and endoscopy. “Other” includes those patients referred from other hospital critical care or intensive care units, same or other hospital high-dependence units, or other intermediate care units

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Intensivists have brought the most important lifesaving therapies performed by other specialists to their patients in critical care units. An early example of this was the innovative use of tracheostomies to treat patients with respiratory failure during the 1952 polio epidemic in Copenhagen, Denmark. During this epidemic, there were not enough “iron lung” ventilators for all polio patients that developed respiratory failure. The use of the tracheostomy artificial airway was a lifesaving measure. It allowed vast numbers of medical students to manually apply positive pressure ventilation. Prior to this use, tracheostomies had only been used to assist breathing to facilitate surgery in operating theaters (Menon and Nightingale 2006). Today, tracheostomy-assisted breathing is routine in critical care wards throughout the world.

Unlike other specialist departments, the practice in critical care units is typically not disease or organ specific. Despite this, a wide range of expertise is required to care for the various conditions and patients that are encountered. The critically ill patient will often require multiple organ support, artificial ventilation, and/or artificial feeding (Menon and Nightingale 2006).

Since the 1980s the recognition of the importance of nutritional support in critical care has increased. In response to this, authoritative organizations have endorsed and overseen the development of training, monitoring, and treatment plans to deliver optimal nutrition support as part of a holistic healthcare approach. In fact in some countries, such as the United States of America, a healthcare establishment will not be accredited unless appropriate nutritional support is included as part of routine clinical practice.

Up to 60 % of critical care patients can be malnourished despite feeding (Calvo et al. 2012). Malnutrition may have developed as a result of the acute effect of a disease or may have been present prior to admission; this is then compounded by critical illness. Appropriate management of malnutrition can significantly influence the course of many diseases and improve clinical outcomes (Agarwal et al. 2012; Lisboa da Silva et al. 2012). Nutritional screening must include an assessment of nutritional status to identify malnutrition and decide the appropriate route and constituents of feed. Screening is often followed by more in-depth assessment if needed. When indicated, delivery of nutrition support is either through oral intake or through artificial nutrition via enteral or parenteral routes. These decisions are often based on pragmatism and on locally agreed policies. Locally agreed policies are typically developed from the guidelines of regional authoritative bodies, for example, the American Society for Parenteral and Enteral Nutrition (ASPEN), the British Association for Parenteral and Enteral Nutrition (BAPEN), the European Society for Clinical Nutrition and Metabolism (ESPEN), or the Society of Critical Care Medicine (SCCM).

The most minimal aim of nutritional support is to maintain hydration and protein-energy balance and prevent or minimize catabolic effects of disease. Enrichment of specific nutrients may be indicated in specific disease states as important advances in research have highlighted the beneficial effects of supplementing feeds with specific micronutrients and vitamins such as selenium or vitamin D or with fish oil emulsions or antioxidants (Hardy et al. 2012; Reddell and Cotton 2012; Nair and Venkatesh 2012; Manzanares et al. 2013).

Given the importance of nutritional support, it is necessary that evidence-based findings are highlighted and collected in resources such as this publication. This book presents a comprehensive collection of the evidence-base for current clinical practice guidelines on nutritional support and future research into the identification and management of malnutrition in critical care wards. This collection of chapters presents work that is clinically relevant and applicable and has been supported by multiple peer-reviewed investigations. Below is a brief list of important resources that advise nutritional management practices in critical care units.

Tables 1–3 list the most up-to-date information on the regulatory bodies and professional societies (Table 1), journals (Table 2), and books (Table 3) that are relevant to an evidence-based incorporation of diet and nutritional support to critical care units.

Table 1 Regulatory bodies and professional societies related to diet and nutrition in critical care. This table lists the important regulatory bodies and professional societies related to diet and nutrition in critical care
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Table 2 Journals important for diet and nutrition in critical care. This table lists examples of important journals that publish peer-reviewed original research and review articles relating to diet and nutrition in critical care
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Table 3 Books important for diet and nutrition in critical care . This table lists examples of important published textbooks with information regarding diet and nutrition in critical care
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Summary Points

  • Critical care units are dedicated to patients in the most fragile health states due to acute illness or deterioration of chronic illness.

  • Healthcare provisions to the critically ill patient require a multidisciplinary team of physicians, specialist nurses, pathologists, dieticians, and other healthcare professionals.

  • Critical care units and the multidisciplinary teams that staff them are central to hospitals and are indispensible to the other departments and services.

  • The care delivered in critical care units is dependent on the care received at the source of admission and will influence patient destination after discharge.

  • Focus on diet and nutrition in critical care units has grown significantly. Many lines of evidence demonstrate the importance of appropriate nutritional support to positive clinical outcomes.

  • This chapter lists the most up-to-date resources, regulatory bodies, professional societies, journals, and books that are relevant to an evidence-based approach to applying dietary and nutritional support to patients in critical care units.