Paul Frost

The route of nutritional support in the critically ill: physiological and economical considerations

Although it generally is accepted that early enteral nutrition is of benefit to critically ill patients, there is little evidence to support this assertion. Nevertheless, enteral nutrition has many advantages over total parenteral nutrition (TPN), the latter being associated with several complications. Animal studies have shown that injury and infection can lead to gut atrophy and increased mucosal permeability. Translocation of bacteria and endotoxin in these animal models may initiate a systemic inflammatory response and cause multiple organ failure (MOF). Again, there is little direct evidence to suggest that similar mechanisms operate in humans. As a cause of MOF, simple splanchnic ischemia and reperfusion may be sufficient with no absolute requirement for translocation. In this setting, enteral nutrition may preserve splanchnic blood flow and prevent mucosal breakdown. Unfortunately there is a widespread misconception that gastric stasis, the absence of bowel sounds, and recent abdominal surgery preclude enteral feeding. There are few absolute contraindications to early enteral feeding and with motivated staff, the use of prokinetics, and the availability of jejunal feeding tubes, the majority of intensive care patients can be fed enterally. Enteral feeding is more cost effective than TPN, but TPN remains a common therapeutic intervention in the intensive care unit and represents a significant burden on health care budgets. Nutrition support teams have led to savings, particularly by identifying patients who have been inappropriately prescribed TPN and also by preventing excessive enteral feeding.

Molecular analysis of microbial communities in endotracheal tube biofilms

Background Ventilator-associated pneumonia is the most prevalent acquired infection of patients on intensive care units and is associated with considerable morbidity and mortality. Evidence suggests that an improved understanding of the composition of the biofilm communities that form on endotracheal tubes may result in the development of improved preventative strategies for ventilator-associated pneumonia. Methodology/Principal Findings The aim of this study was to characterise microbial biofilms on the inner luminal surface of extubated endotracheal tubes from ICU patients using PCR and molecular profiling. Twenty-four endotracheal tubes were obtained from twenty mechanically ventilated patients. Denaturing gradient gel electrophoresis (DGGE) profiling of 16S rRNA gene amplicons was used to assess the diversity of the bacterial population, together with species specific PCR of key marker oral microorganisms and a quantitative assessment of culturable aerobic bacteria. Analysis of culturable aerobic bacteria revealed a range of colonisation from no growth to 2.1×108 colony forming units (cfu)/cm2 of endotracheal tube (mean 1.4×107 cfu/cm2). PCR targeting of specific bacterial species detected the oral bacteria Streptococcus mutans (n = 5) and Porphyromonas gingivalis (n = 5). DGGE profiling of the endotracheal biofilms revealed complex banding patterns containing between 3 and 22 (mean 6) bands per tube, thus demonstrating the marked complexity of the constituent biofilms. Significant inter-patient diversity was evident. The number of DGGE bands detected was not related to total viable microbial counts or the duration of intubation. Conclusions/Significance Molecular profiling using DGGE demonstrated considerable biofilm compositional complexity and inter-patient diversity and provides a rapid method for the further study of biofilm composition in longitudinal and interventional studies. The presence of oral microorganisms in endotracheal tube biofilms suggests that these may be important in biofilm development and may provide a therapeutic target for the prevention of ventilator-associated pneumonia.

Early management of acutely ill ward patients

How junior doctors can develop a systematic approach to managing patients with acute illness in hospital

Efficacy of oral chlorhexidine in critical care

In their review of airway hygiene, Jelic and colleagues highlighted that colonization or infection of the upper airway precedes the development of ventilator-associated pneumonia [1]. Although the effects of chlorhexidine on reducing pneumonia were discussed, there was no mention of the possible contribution of physical plaque removal, in particular tooth brushing, which is often performed either infrequently or inadequately in mechanically ventilated patients [1]. Such removal is important because in critically ill patients the normal microflora of dental plaque becomes rapidly colonized by potential pathogens, and this biofilm serves as a reservoir for the subsequent development of ventilator-associated pneumonia [2,3]. Physical removal of dental plaque is essential for the optimal benefit of chlorhexidine since its primary action is inhibition of plaque formation. Whilst chlorhexidine kills both Gram-negative bacteria and Gram-positive bacteria by damaging their cell wall, its antiplaque activity is superior to other antiseptics with greater antibacterial activity. This superior activity occurs because chlorhexidine is absorbed onto oral surfaces and is released over a long period of time. This property, known as substantivity, explains why chlorhexidine is excellent at inhibiting plaque formation in a clean mouth but is otherwise of limited efficacy [4]. It is also not generally appreciated that if toothpaste is used prior to chlorhexidine then it must be thoroughly removed to prevent formation of inactive low-solubility salts [5]. Oral chlorhexidine is widely used in critical care practice and has been the subject of many investigations in mechanically ventilated patients. These studies unfortunately do not address the essential need for mechanical cleaning prior to chlorhexidine use and therefore potentially underestimate the benefit of this agent in reducing ventilator-associated pneumonia.

Intravenous fluid therapy in adult inpatients

#### The bottom line Intravenous fluid management is a common medical task, and safe unambiguous fluid prescribing is a required training outcome for junior doctors.1 Despite this, errors in intravenous fluid management are common and have been attributed to inadequate training and knowledge.2 Poor fluid management can result in serious morbidity, such as pulmonary oedema and dangerous hyponatraemia as a result of excessive fluids and acute kidney injury as a result of under resuscitation.2 3 There is a lack of high quality evidence, such as that from randomised controlled trials, to guide intravenous fluid management.4 Safe intravenous fluid prescribing requires the integration of relevant clinical skills, such as the assessment of fluid balance, with an understanding of fluid physiology under normal and pathological conditions and the properties of commonly available intravenous fluids. Water constitutes about 60% of the total body weight in men and 55% in women (women have a slightly higher fat content). Although water is non-uniformly distributed throughout the body, it can be conceptualised as occupying the intracellular and extracellular fluid compartments (fig 1⇓). Extracellular fluid mainly comprises plasma and interstitial fluid, which are separated by the capillary membrane. Fig 1 Body fluid compartment volumes and theoretical distribution of intravenous fluids in healthy people ### Water movement between the plasma and interstitial spaces The capillary endothelium is lined by …

Macrolides and community-acquired pneumonia: is quorum sensing the key?

Combination therapy with two antimicrobial agents is superior to monotherapy in severe community-acquired pneumonia, and recent data suggest that addition of a macrolide as the second antibiotic might be superior to other combinations. This observation requires confirmation in a randomised control trial, but this group of antibiotics have pleiotropic effects that extend beyond bacterial killing. Macrolides inhibit bacterial cell-to-cell communication or quorum sensing, which not only might be an important mechanism of action for these drugs in severe infections but may also provide a novel target for the development of new anti-infective drugs.

Tracheotomy and ventilator-associated pneumonia: the importance of oral care

To the Editors: We read with interest the recent study of Nseir et al. 1, which demonstrated that tracheotomy was independently associated with a decreased risk of ventilator-associated pneumonia (VAP). The authors offered several potential explanations as to why tracheotomised patients should be at decreased risk of VAP compared to patients with …

Managing sudden death in hospital.

Junior doctors play an important role in verifying sudden deaths in hospital and communicating with the family of the deceased. This article covers England and Wales; the situation in Scotland and Northern Ireland differs in some respects

Esomeprazole for asthma.

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Cardiorespiratory arrests and rapid response teams in pediatrics.

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