| Abstract | Summary of a study, which may be published alone or as an introduction to a full scientific paper. |
| Alcohol- based/Alcoholic handrub | An alcohol-containing preparation designed for application to the hands for reducing the number of viable microorganisms on the hands. In the UK, such preparations usually contain 60–90% ethanol and isopropanol. |
| Algorithm (in guidelines) | A flow chart of the clinical decision pathway described in the guideline, where decision points are represented with boxes, linked with arrows. |
| Allocation concealment | The process used to prevent advance knowledge of group assignment in an RCT. The allocation process should be impervious to any influence by the individual making the allocation, by being administered by someone who is not responsible for recruiting participants. |
| Antiseptic handwash or soap | An antiseptic containing preparation designed for frequent use; it reduces the number of microorganisms on intact skin to an initial baseline level after adequate washing, rinsing, and drying; it is broad-spectrum and fast-acting. |
| Applicability | The degree to which the results of an observation, study or review are likely to hold true in a particular clinical practice setting. |
| Arm (of a clinical study) | Sub-section of individuals within a study who receive one particular intervention, for example placebo arm. |
| Asepsis | Asepsis prevents microbial contamination during procedures where the body’s natural defences are bypassed.
Asepsis can be defined as medical or surgical. Medical asepsis aims to reduce the number of organisms and prevent their spread by key principles such as decontaminating hands, use of PPE and not touching key parts.
Surgical asepsis is a strict process and includes procedures to eliminate micro-organisms from an area (thus creating a sterile environment) and is practised in operating theatres and for invasive procedures such as the insertion of a central venous catheter.
See also ‘aseptic techniques’. |
| Aseptic non touch technique (ANTT™) | A specific type of aseptic technique with a unique theory and practice framework (www.antt.co.uk). |
| Aseptic techniques | An aseptic technique ensures that only uncontaminated equipment and fluids come into contact with susceptible body sites. It should be used during any clinical procedure that bypasses the body’s natural defences. Using the principles of aspepsis minimises the spread of organisms from one person to another. See ‘asepsis’. |
| Autonomic dysreflexia | Autonomic dysreflexia, also known as hyperreflexia, is where a stimulus, such as overstretching or irritation of the bladder wall, causes an over-activity of the sympathetic part of the autonomic nervous system resulting in remarkably high blood pressure (often ≥200mm/Hg systolic). |
| Bacteraemia | The presence of bacteria in the bloodstream. |
| Bacteriuria | The presence of bacteria in the urine with or without associated symptoms of infection. In the absence of symptoms this is referred to as asymptomatic bacteriuria or, in the case of a patient with an indwelling catheter, catheter colonisation. |
| Bare below the elbows | The GDG defined this as not wearing false nails or nail polish when delivering direct patient care. Not wearing a wrist-watch or stoned rings. Healthcare workers’ garments should be short sleeved or be able to roll or push up sleeves when delivering direct patient care and performing hand decontamination. |
| Baseline | The initial set of measurements at the beginning of a study (after run-in period where applicable), with which subsequent results are compared. |
| Bias | Systematic (as opposed to random) deviation of the results of a study from the ‘true’ results that is caused by the way the study is designed or conducted. |
| Bladder instillation | Introducing a sterile therapeutic liquid into the bladder and leaving it there for a variable ‘holding’ time to dissolve particulates/encrustation, altering pH, or suppressing bacterial growth. |
| Bladder irrigation | The continuous introduction of a sterile fluid into the bladder via a three way catheter to allow for the drainage of blood and debris from the bladder. |
| Bladder washout | The introduction into the bladder of a sterile fluid which is allowed to drain more or less immediately, for the purpose of diluting the bladder contents/unblocking an obstruction to restore free catheter drainage. |
| Blinding | Keeping the study participants, caregivers, researchers and outcome assessors unaware about the interventions to which the participants have been allocated in a study. |
| Blood borne viruses | A virus that is carried in the bloodstream, and transmitted via contact with infected blood e.g. HBV, HCV and HIV. |
| Bodily fluid contamination | Contamination with any bodily fluid which would include urine, faeces, saliva or vomit and could result in transmission of infection. |
| Buried bumper syndrome | A complication of PEG tubes where the internal disc becomes buried in the stomach lining. |
| C.diff cross infection | The transmission of Clostridium difficile from one person to another because of a breach in a barrier. |
| C.diff reduction | A reduction in the incidence (number of new cases) of Clostridium difficile. |
| Cannula | A peripheral device consisting of a hollow tube made of plastic or metal, used for accessing the body. |
| Carer (caregiver) | Someone other than a health professional who is involved in caring for a person with a medical condition. |
| Catheter blockage | Blockage either by deposits and encrustations or by mechanical means, such as occlusion of catheter due to kinking of the tube, that prevents urine from draining out of the bladder. |
| Catheter encrustation | Deposits of gritty urine crystals on the catheter tube which can increase the risk of blockage and infection. |
| Catheter thrombus | Clot adherent to or occluding the catheter or a fibrin sleeve in the vessel around the catheter. |
| Catheter tip colonisation | In clinical studies on the prevention of vascular catheter-related infections, catheter-tip colonization (CTC) is frequently used as a surrogate end point for the most severe form of vascular catheter-related infection, catheter-related BSI. Use of this end point is based on observations that, in bacteraemic patients who have an intravascular catheter in place, the catheter is more likely to be the source of bacteraemia if culture of the catheter tip yields the same bacteria as blood culture. The higher the load of bacteria found on the catheter, the better the positive predictive value for catheter-related bacteraemia. More recently, and for practical reasons—in most studies of catheter-related infection, an absolute cut off value for catheter culture positivity has been used. |
| Catheter valve | A valve connected to the catheter outlet allowing the bladder to be used to store urine. Urine is drained by opening the valve at regular intervals. |
| Catheter-associated Urinary Tract Infection | The occurrence of local, or distant, clinical symptoms or signs attributable to bacteria present either within the urinary tract, or in the bloodstream (with the urinary tract as the source).
Infection may arise:
either at the time of, or immediately following catheter insertion; or subsequently, because the colonising flora within the catheterised urinary tract becomes invasive (this may occur spontaneously, or follow catheter manipulation).
|
| Cellulitis | An infection of the skin and tissues beneath the skin, symptoms include tenderness, swelling, erythema and may cause pyrexia. |
| Central venous catheter | Catheter inserted into a centrally located vein with the tip residing in the lower third of the superior vena cava: permits access to the venous system. |
| Clean procedure | Hands are decontaminated before and after the procedure and key parts are not touched. |
| Clean technique | A technique that is designed to prevent the introduction of microorganisms, but in recognition that the site is already colonised with bacteria it is not aseptic. Non sterile gloves may be used. |
| Clinical effectiveness | The extent to which an intervention produces an overall health benefit in routine clinical practice. |
| Clinical efficacy | The extent to which an intervention is active when studied under controlled research conditions. |
| Clinical importance | This refers to whether the size of the effect observed between groups are If the MID is less than the lower limit of the 95% confidence interval, results are likely to be statistically significant and clinically important. If the MID is greater than the upper limit of the 95% confidence interval, results are likely to be clinically unimportant. If the MID lies within the limits of the 95% confidence interval, it is unclear if the effect is clinically important or not41. |
| Clinical waste | Clinical waste is defined as:
“. . . any waste which consists wholly or partly of human or animal tissue, blood or other body fluids, excretions, drugs or other pharmaceutical products, swabs or dressings, syringes, needles or other sharp instruments, being waste which unless rendered safe may prove hazardous to any person coming into contact with it; and any other waste arising from medical, nursing, dental, veterinary, pharmaceutical or similar practice, investigation, treatment, care, teaching or research, or the collection of blood for transfusion, being waste which may cause infection to any person coming into contact with it.”
Clinical waste can be divided into three broad groups of materials:
any healthcare waste which poses a risk of infection (and therefore by definition possesses the hazardous property H9 Infectious); certain healthcare wastes which pose a chemical hazard (for example one of H1 to H8, H10 to H15); medicines and medicinally-contaminated waste containing a pharmaceutically-active agent.
|
| Clinician | A healthcare professional providing direct patient care, for example doctor, nurse or physiotherapist. |
| Closed System (enteral feeding) | Sterile, pre-filled ready-to-use feeds that do not expose the feed to the air during assembly. |
| Cohort study | A retrospective or prospective follow-up study. Groups of individuals to be followed up are defined on the basis of presence or absence of exposure to a suspected risk factor or intervention. A cohort study can be comparative, in which case two or more groups are selected on the basis of differences in their exposure to the agent of interest. |
| Colony forming units | A measure of viable bacteria or fungi numbers per millilitre. |
| Comparability | Similarity of the groups in characteristics likely to affect the study results (such as health status or age). |
| Concordance | This is a recent term whose meaning has changed. It was initially applied to the consultation process in which doctor and patient agree therapeutic decisions that incorporate their respective views, but now includes patient support in medicine taking as well as prescribing communication. Concordance reflects social values but does not address medicine-taking and may not lead to improved adherence. |
| Confidence interval (CI) | A range of values for an unknown population parameter with a stated ‘confidence’ (conventionally 95%) that it contains the true value. The interval is calculated from sample data, and generally straddles the sample estimate. The ‘confidence’ value means that if the method used to calculate the interval is repeated many times, then that proportion of intervals will actually contain the true value. |
| Confounding | In a study, confounding occurs when the effect of an intervention on an outcome is distorted as a result of an association between the population or intervention or outcome and another factor (the ‘confounding variable’) that can influence the outcome independently of the intervention under study. |
| Consensus methods | Techniques that aim to reach an agreement on a particular issue. Consensus methods may be used when there is a lack of strong evidence on a particular topic. |
| Control group | A group of patients recruited into a study that receives no treatment, a treatment of known effect, or a placebo (dummy treatment) - in order to provide a comparison for a group receiving an experimental treatment, such as a new drug. |
| Cost benefit analysis | A type of economic evaluation where both costs and benefits of healthcare treatment are measured in the same monetary units. If benefits exceed costs, the evaluation would recommend providing the treatment. |
| Cost-consequence analysis (CCA) | A type of economic evaluation where various health outcomes are reported in addition to cost for each intervention, but there is no overall measure of health gain. |
| Cost-effectiveness analysis (CEA) | An economic study design in which consequences of different interventions are measured using a single outcome, usually in ‘natural’ units (for example, life-years gained, deaths avoided, heart attacks avoided, cases detected). Alternative interventions are then compared in terms of cost per unit of effectiveness. |
| Cost-effectiveness model | An explicit mathematical framework, which is used to represent clinical decision problems and incorporate evidence from a variety of sources in order to estimate the costs and health outcomes. |
| Cost-utility analysis (CUA) | A form of cost-effectiveness analysis in which the units of effectiveness are quality-adjusted life-years (QALYs). |
| Catheter-related bloodstream infection (CRBSI) | The patient has one or more recognized pathogens cultured from a single blood culture
OR
If the microorganism is a common skin organism then...
It must have been cultured from 2 or more blood cultures drawn on separate occasions, or from one blood culture in a patient in whom antimicrobial therapy has been started, and Patient has one of the following: fever of >38°C, chills, or hypotension
AND
AND one of the following:
a positive semiquantitative (>15 CFU/catheter segment) or quantitative (>103 CFU /ml or >103 CFU/catheter segment) culture whereby the same organism (species and antibiogram) is isolated from blood sampled from the CVC or from the catheter tip, and peripheral blood; simultaneous quantitative blood cultures with a >5:1 ratio CVC versus peripheral.
|
| Credible Interval | The Bayesian equivalent of a confidence interval. |
| Decision analysis | An explicit quantitative approach to decision making under uncertainty, based on evidence from research. This evidence is translated into probabilities, and then into diagrams or decision trees which direct the clinician through a succession of possible scenarios, actions and outcomes. |
| Dermatitis (Standard infection control) | Inflammation of the skin either due to direct contact with an irritant or due to an allergic reaction. It maybe eczematous or non eczematous. Non eczematous is usually due to direct contact with an irritant. |
| Direct patient care | Hands-on or face-to-face contact with patients. Any physical aspect of the healthcare of a patient, including treatments, self-care, and administration of medication. |
| Discounting | Discounting makes current costs and benefits worth more than those that occur in the future. This is common practice in health economic evaluation due to the ‘time preference’ expressed by most people, in which there is a desire to enjoy benefits in the present while deferring the negative. |
| Disposable gloves | Gloves that are used for single-use only, these may be latex, latex free or vinyl. |
| Disposable plastic aprons | An apron which is for single-use and normally made from a plastic material. |
| Dominance | An intervention is said to be dominated if there is an alternative intervention that is both less costly and more effective. |
| Drop-out | A participant who withdraws from a trial before the end. |
| Economic evaluation | Comparative analysis of alternative health strategies (interventions or programmes) in terms of both their costs and consequences. |
| Effect (as in effect measure, treatment effect, estimate of effect, effect size) | The observed association between interventions and outcomes or a statistic to summarise the strength of the observed association. |
| Effectiveness | See ‘Clinical effectiveness’. |
| Efficacy | See ‘Clinical efficacy’. |
| Enteral feeding | Feeding via a tube that can include any method of providing nutrition via the gastrointestinal tract. |
| Epidemiological study | The study of a disease within a population, defining its incidence and prevalence and examining the roles of external influences (for example, infection, diet) and interventions. |
| EQ-5D (EuroQol-5D) | A standardised instrument used to measure health-related quality of life. It provides a single utility value for a health state. |
| Evidence | Information on which a decision or guidance is based. Evidence is obtained from a range of sources including randomised controlled trials, observational studies, and expert opinion (of clinical professionals and/or patients). |
| Exclusion criteria (clinical study) | Criteria that define who is not eligible to participate in a clinical study. |
| Exclusion criteria (literature review) | Explicit standards used to decide which studies should be excluded from consideration as potential sources of evidence. |
| Expert opinion | Opinion derived from seminal works and appraised national and international guidelines. This also includes invited clinical experts. |
| Extended dominance | If Option A is both more clinically effective than Option B and has a lower cost per unit of effect, when both are compared with a do-nothing alternative then Option A is said to have extended dominance over Option B. Option A is therefore more efficient and should be preferred, other things remaining equal. |
| Extrapolation | In data analysis, predicting the value of a parameter outside the range of observed values. |
| Fill line | The manufacturer’s mark on the sharps bin that relates to the bin being ¾ full. |
| Follow up | Observation over a period of time of an individual, group or initially defined population whose appropriate characteristics have been assessed in order to observe changes in health status or health related variables. |
| Full body fluid repellent gowns | Full gown that includes full length sleeves that is fluid repellent and should be used when there is excessive risk of splashing of bodily fluids and secretions. |
| Fungal Colonisation | The presence of fungi on the skin that does not cause disease. |
| Gastrostomy site infection | An infection of the gastrostomy site often caused by skin flora which includes inflammation around the insertion site. There may be associated pus formation. |
| Gauze dressings | Woven or nonwoven fabric swab. |
| GDG Consensus | GDG Consensus may be used when there is a lack of strong evidence on a particular topic to reach an agreement for a recommendation. |
| Gel reservoir catheter | A type of intermittent catheter that is lubricated by passing it through a pre-packaged sterile integral reservoir of lubricating gel. Also known as ‘pre-gelled’. |
| Generalisability | The extent to which the results of a study based on measurement in a particular patient population and/or a specific context hold true for another population and/or in a different context. In this instance, this is the degree to which the guideline recommendation is applicable across both geographical and contextual settings. For instance, guidelines that suggest substituting one form of labour for another should acknowledge that these costs might vary across the country. |
| Gloves porosity | The risk of micropuncture within the gloves structure that allows fluids to breach the glove surface. Defined by the amount of spaces/voids within a solid material which can absorb fluids. |
| Gold standard | See ‘Reference standard’. |
| GRADE / GRADE profile | A system developed by the GRADE Working Group to address the shortcomings of present grading systems in healthcare. The GRADE system uses a common, sensible and transparent approach to grading the quality of evidence. The results of applying the GRADE system to clinical trial data are displayed in a table known as a GRADE profile. |
| Hazard analysis and critical control point (HACCP) | A system to identify potential hazards in food preparation. |
| Hand decontamination | The use of handrub or handwashing to reduce the number of bacteria on the hands. In this guideline this term is interchangeable with ‘hand hygiene’. |
| Hand hygiene | See “Hand decontamination”. |
| Hand decontamination compliance | A measure of compliance to best practice ideals or policy related to hand decontamination. |
| Handrub (compliant with EN 1500) | A preparation applied to the hands to reduce the number of viable microorganisms. This guideline refers to handrubs compliant with British standards (BS EN1500; standard for efficacy of hygienic handrubs using a reference of 60% isopropyl alcohol). |
| Hand washing | Washing hands with plain (i.e. nonantimicrobial) soap and water. |
| Hand to hand | The act of passing (a sharp) from one person to another. |
| Hand /skin wipes | Moist towelettes impregnated with various products used for cleansing of skin, or inactivating pathogenic microorganisms on the skin. |
| Hang time | The total time during which the feed is held in the nutrient container at room temperature while being administered. This includes periods of time when administration of the feed is interrupted temporarily. |
| Harms | Adverse effects of an intervention. |
| Health economics | The study of the allocation of scarce resources among alternative healthcare treatments. Health economists are concerned with both increasing the average level of health in the population and improving the distribution of health. |
| Healthcare-associated infection | Infections that occur as a result of contact with the healthcare system in its widest sense – in community and hospital settings. Previously, when most complex healthcare was hospital based, the term ‘hospital acquired (or nosocomial) infection’ was used. (See Nosocomial infection) |
| Healthcare waste | Waste from natal care, diagnosis, treatment or prevention of disease in humans/animals. Examples of healthcare waste include:
|
| Healthcare worker | Any person employed by the health service, social service, local authority or agency to provide care for sick, disabled or elderly people. |
| Health-related quality of life (HRQoL) | A combination of an individual’s physical, mental and social well-being; not merely the absence of disease. |
| Heterogeneity (or lack of homogeneity) | The term is used in meta-analyses and systematic reviews when the results or estimates of effects of treatment from separate studies seem to be very different – in terms of the size of treatment effects or even to the extent that some indicate beneficial and others suggest adverse treatment effects. Such results may occur as a result of differences between studies in terms of the patient populations, outcome measures, definition of variables or duration of follow-up. |
| Hydrophilic catheter | Hydrophilic urinary catheters are coated with a water absorbent polymer. When exposed to water the coating becomes wet and slippery, reducing friction between the catheter surface and the urethral mucosa during insertion. Hydrophilic catheters are sterile and have either packaged with an activated coating (i.e. ready to use) or a dry coating which requires immersion in water for 30 seconds in order to activate the coating. |
| Hypersensitivity | A state of altered reactivity in which the body reacts with an exaggerated immune response to what is perceived as a foreign substance. |
| Implanted port | A VAD catheter surgically placed into a vein and attached to a reservoir located under the skin (usually in the chest region). The catheter is tunnelled under the skin and the tip lies in the lower third of the superior vena cava. |
| Imprecision | Results are imprecise when studies include relatively few patients and few events and thus have wide confidence intervals around the estimate of effect. |
| Impregnated dressings | Dressing permeated with a chemical, usually with antimicrobial properties, to reduce the level of bacteria at the wound surface. Examples of active ingredients include: medical grade honey, iodine, silver and chlorhexidine. |
| Inclusion criteria | Explicit criteria used to decide which studies should be considered as potential sources of evidence. |
| Incremental analysis | The analysis of additional costs and additional clinical outcomes with different interventions. |
| Incremental cost | The mean cost per patient associated with an intervention minus the mean cost per patient associated with a comparator intervention. |
| Incremental cost effectiveness ratio (ICER) | The difference in the mean costs in the population of interest divided by the differences in the mean outcomes in the population of interest for one treatment compared with another. |
| Incremental net benefit (INB) | The value (usually in monetary terms) of an intervention net of its cost compared with a comparator intervention. The INB can be calculated for a given cost-effectiveness (willingness to pay) threshold. If the threshold is £20,000 per QALY gained then the INB is calculated as: (£20,000 × QALYs gained) − Incremental cost. |
| Indirectness | The available evidence is different to the review question being addressed, in terms of PICO (population, intervention, comparison and outcome). |
| Indwelling (urethral) catheter | A catheter that is inserted into the bladder via the urethra and remains in place for a period of time. |
| Infusate-related BSI (Bloodstream Infection) | Concordant growth of the same organism from the infusate and blood cultures (preferably percutaneously drawn) with no other identifiable source of infection. |
| Injection access site, such as caps/ ports | Resealable cap or other configuration designed to accommodate needles or needleless devices for administration of solutions into the vascular system. Also includes injection caps, needle free caps, catheter hubs or administration ports integral to an administration set. |
| Intention to treat analysis (ITT) | A strategy for analysing data from a randomised controlled trial. All participants are included in the arm to which they were allocated, whether or not they received (or completed) the intervention given to that arm. Intention-to-treat analysis prevents bias caused by the loss of participants, which may disrupt the baseline equivalence established by randomisation and which may reflect non-adherence to the protocol. |
| Intervention | Healthcare action intended to benefit the patient, for example, drug treatment, surgical procedure, psychological therapy. |
| Kappa statistic | A statistical measure of inter-rater agreement that takes into account the agreement occurring by chance. |
| Length of stay | The total number of days a participant stays in hospital. |
| Licence | See ‘Product licence’. |
| Life-years gained | Mean average years of life gained per person as a result of the intervention compared with an alternative intervention. |
| Likelihood ratio | The likelihood ratio combines information about the sensitivity and specificity. It tells you how much a positive or negative result changes the likelihood that a patient would have the disease. The likelihood ratio of a positive test result (LR+) is sensitivity divided by 1-specificity. |
| Link system | An extension attached to the drainage outlet of the day urine collection bag and connected to a larger capacity night drainage bag. |
| Localised Catheter Colonisation | Significant growth of a microorganism (> 15 CFU) from the catheter tip, subcutaneous segment of the catheter, or catheter hub in the absence of a positive blood culture. |
| Long-term care | Residential care in a home that may include skilled nursing care and help with everyday activities. This includes nursing homes and residential homes. |
| Long-term catheterisation | Long-term catheterisation: The use of a catheter (indwelling or intermittent) for a period greater than 28 days. |
| Loss to follow-up | Also known as attrition. The loss of participants during the course of a study. Participants that are lost during the study are often call dropouts. |
| Markov model | A method for estimating long-term costs and effects for recurrent or chronic conditions, based on health states and the probability of transition between them within a given time period (cycle). |
| Meta-analysis | A statistical technique for combining (pooling) the results of a number of studies that address the same question and report on the same outcomes to produce a summary result. The aim is to derive more precise and clear information from a large data pool. It is generally more reliably likely to confirm or refute a hypothesis than the individual trials. |
| Midline catheter | A peripheral device that permits venous access. The catheter is inserted via the antecubital veins and advanced into the veins of the upper arm but not extending past the axilla (usually about 20cm in length). It is used for short-term (up to four weeks) intravenous access. |
| MCID (minimal clinical important difference) | Minimal clinical important difference (MCID) was defined as smallest difference in score in the outcome of interest that informed patients or informed proxies perceive as important, either beneficial or harmful, and that would lead the patient or clinician to consider a change in the management 129. This is also sometimes referred as “minimal important change” in clinical papers. See MID, clinical importance, statistical significance. |
| MID (minimal important difference) | The MID is the smallest difference in score in the outcome of interest that informed patients or informed proxies perceive as important, either beneficial or harmful, and that would lead the patient or clinician to consider a change in the management 129,233,234. This term was adapted from the earlier definition used for MCID (minimal clinically important difference) with the term “clinical” removed to emphasise on the importance of patient perspective. The term “MID” has been adopted by GRADE. In this guideline, we also use the term to refer to the clinically important thresholds or harms when considering imprecision. See MCID, clinical importance, statistical significance. |
| MRSA cross infection | The transmission of the disease from one person to another because of a breach in a barrier. |
| MRSA reduction | A reduction in the incidence (number of new cases) of MRSA. |
| Multivariate model | A statistical model for analysis of the relationship between two or more predictor (independent) variables and the outcome (dependent) variable. |
| Needle safety devices | Any device that aims to reduce the incidence of sharps’ injuries. This may include needleless syringes, needle protection devices and needle free devices (see safety needle devices). |
| Night drainage bag | Bags used for overnight urine collection. |
| Non-alcohol based decontamination products | Hand washing products that do not contain alcohol, such as plain soap and water, or antimicrobial/antiseptic washes. |
| Nosocomial | Related to hospital or care, e.g., nosocomial infection is a hospital-acquired infection. |
| Number needed to treat (NNT) | The number of patients that who on average must be treated to prevent a single occurrence of the outcome of interest. |
| Observational study | Retrospective or prospective study in which the investigator observes the natural course of events with or without control groups; for example, cohort studies and case–control studies. |
| Open System | Feeds that need to be reconstituted, diluted and/or decanted into a feed container and/or where the feed is exposed to the atmosphere during assembly of feeding system. |
| Opportunity cost | The loss of other healthcare programmes displaced by investment in or introduction of another intervention. This may be best measured by the health benefits that could have been achieved had the money been spent on the next best alternative healthcare intervention. |
| Outcome | Measure of the possible results that may stem from exposure to a preventive or therapeutic intervention. Outcome measures may be intermediate endpoints or they can be final endpoints. See ‘Intermediate outcome’. |
| Percutaneous endoscopic gastrstomy feeding tube | A polyurethane or silicone tube, which has been inserted directly through the abdominal wall into the stomach. An internal retention disc (flange) anchors the tube in place and prevents the leakage of gastric juices or food. An external fixation plate keeps the PEG in position next to the skin. They are suitable for long-term use. |
| Peristomal infection | Oropharyngeal bacteria can be brought through the abdominal wall during percutaneous endoscopic gastrostomy (PEG). Peristomal infection is one of the most frequent complications in patients who undergo the procedure. |
| Peritonitis | Inflammation of the peritoneum (the membrane lining the inner wall of the abdomen and pelvis). Peritonitis may be primary (ie spontaneous, usually associated with ascites) or secondary due to: infection by bacteria or parasites; bleeding; leakage of irritants (such as bile, stomach acid or pancreatic enzymes); or some systemic diseases (e.g. porphyria). It can result from bacteria tracking inwards/internally from the gastrostomy site. |
| Persistent activity or residual activity | Persistent activity is defined as the prolonged or extended antimicrobial activity that prevents or inhibits the proliferation or survival of microorganisms after application of the product. This activity may be demonstrated by sampling a site several minutes or hours after application and demonstrating bacterial antimicrobial effectiveness when compared with a baseline level. This property also has been referred to as “residual activity.” Both substantive and nonsubstantive active ingredients can show a persistent effect if they substantially lower the number of bacteria during the wash period. |
| Personal Protective Equipment (PPE) | All equipment which is intended to be worn or held by a person to protect them from risks to health and safety whilst at work. Examples of PPE include gloves, aprons and eye and face protection. |
| Peripherally inserted central catheter (PICC) | Soft flexible central venous catheter inserted into an arm vein and advanced until the tip is positioned in the lower third of the superior vena cava. Permits access to the venous system. |
| Placebo | An inactive and physically identical medication or procedure used as a comparator in controlled clinical trials. |
| Plain soap | Detergents that do not contain antimicrobial agents or contain low concentrations of antimicrobial agents that are effective solely as preservatives. |
| Power (statistical) | The ability to demonstrate an association when one exists. Power is related to sample size; the larger the sample size, the greater the power and the lower the risk that a possible association could be missed. |
| Primary care | Healthcare delivered to patients outside hospitals. Primary care covers a range of services provided by general practitioners, nurses, dentists, pharmacists, opticians and other healthcare professionals. |
| Primary outcome | The outcome of greatest importance, usually the one in a study that the power calculation is based on. |
| Product licence | An authorisation from the MHRA to market a medicinal product. |
| Prospective study | A study in which people are entered into the research and then followed up over a period of time with future events recorded as they happen. This contrasts with studies that are retrospective. |
| Publication bias | Also known as reporting bias. A bias caused by only a subset of all the relevant data being available. The publication of research can depend on the nature and direction of the study results. Studies in which an intervention is not found to be effective are sometimes not published. Because of this, systematic reviews that fail to include unpublished studies may overestimate the true effect of an intervention. In addition, a published report might present a biased set of results (e.g. only outcomes or sub-groups where a statistically significant difference was found). |
| Pulmonary aspiration | Entry of secretions or foreign material, including gastrostomy feed, via the trachea into the lungs. |
| P-value | The probability that an observed difference could have occurred by chance, assuming that there is in fact no underlying difference between the means of the observations. If the probability is less than 1 in 20, the P value is less than 0.05; a result with a P value of less than 0.05 is conventionally considered to be ‘statistically significant’. |
| Quality of life | See ‘Health-related quality of life’. |
| Quality-adjusted life year (QALY) | An index of survival that is adjusted to account for the patient’s quality of life during this time. QALYs have the advantage of incorporating changes in both quantity (longevity/mortality) and quality (morbidity, psychological, functional, social and other factors) of life. It is used to measure benefits in cost-utility analysis. The QALYs gained are the mean QALYs associated with one treatment minus the mean QALYs associated with an alternative treatment. |
| Randomisation | Allocation of participants in a research study to two or more alternative groups using a chance procedure, such as computer-generated random numbers. This approach is used in an attempt to ensure there is an even distribution of participants with different characteristics between groups and thus reduce sources of bias. |
| Randomised controlled trial (RCT) | A comparative study in which participants are randomly allocated to intervention and control groups and followed up to examine differences in outcomes between the groups. |
| Ready-to-use | Feeds prepared and supplied by the manufacturer, that only require attaching to the feeding tube. |
| Relative risk (RR) | The number of times more likely or less likely an event is to happen in one group compared with another (calculated as the risk of the event in group A/the risk of the event in group B). |
| Removal of physical contamination | The procedure which enables the user to clean all contamination from a specific surface. |
| Reporting bias | See ‘publication bias’. |
| Resident (hand) flora | Microorganisms that colonise the deeper crevices of the skin and hair follicles as they have adapted to the hostile environment. Not readily transferred to other people or objects. Not easily removed by the mechanical action of soap and water, but can be reduced in number with the use of an antiseptic solution. |
| Resource implication | The likely impact in terms of finance, workforce or other NHS resources. |
| Retractable needles | Built-in safety mechanism is activated by fully depressing plunger while needle is still in patient. Once activated, needle is automatically retracted from patient, virtually eliminating exposure. |
| Retrospective study | A retrospective study deals with the present/past and does not involve studying future events. This contrasts with studies that are prospective. |
| Reusable syringe | See ‘single patient use’. |
| Review question | In guideline development, this term refers to the questions about treatment and care that are formulated to guide the development of evidence-based recommendations. |
| Risk assessment | Making a suitable and sufficient assessment of risks. This will involve identifying the hazards (something with the potential to do harm), and evaluating the extent of risks (the likelihood that the harm from a particular hazard is realised); and identifying measures needed to comply with legal requirements. |
| Safety cannula | A type of cannula that prevents sharps injuries. These can be active (requires pressing a button to trigger the withdrawal of the needle into a plastic sleeve using a spring) or passive (with a protective shield that automatically covers the needlepoint during its withdrawal) |
| Safety needle devices | These include needle free devices, retractable needles and safety resheathing devices that reduces the risk of sharps injuries. |
| Secondary outcome | An outcome used to evaluate additional effects of the intervention deemed a priori as being less important than the primary outcomes. |
| Selection bias | A systematic bias in selecting participants for study groups, so that the groups have differences in prognosis and/or therapeutic sensitivities at baseline. Randomisation (with concealed allocation) of patients protects against this bias. |
| Self-catheterisation | Intermittent self-catheterisation: urinary catheterisation is undertaken by the patient to drain the bladder with the immediate removal of the catheter. Intermittent catheterisation: urinary catheterisation is performed by a carer with the immediate removal of the catheter. |
| Sensitivity analysis | A means of representing uncertainty in the results of economic evaluations. Uncertainty may arise from missing data, imprecise estimates or methodological controversy. Sensitivity analysis also allows for exploring the generalisability of results to other settings. The analysis is repeated using different assumptions to examine the effect on the results.
One-way simple sensitivity analysis (univariate analysis): each parameter is varied individually in order to isolate the consequences of each parameter on the results of the study.
Multi-way simple sensitivity analysis (scenario analysis): two or more parameters are varied at the same time and the overall effect on the results is evaluated.
Threshold sensitivity analysis: the critical value of parameters above or below which the conclusions of the study will change are identified.
Probabilistic sensitivity analysis: probability distributions are assigned to the uncertain parameters and are incorporated into evaluation models based on decision analytical techniques (for example, Monte Carlo simulation). |
| Sepsis | A systemic response typically to a serious usually localized infection (as of the abdomen or lungs) especially of bacterial origin that is usually marked by abnormal body temperature and white blood cell count, tachycardia, and tachypnoea; specifically: systemic inflammatory response syndrome induced by a documented infection. |
| Septicaemia | Invasion of the bloodstream by virulent microorganisms (including bacteria, viruses, or fungi) from a focus of infection that is accompanied by acute systemic illness.
Also called blood poisoning. |
| Sharps | Sharps are any medical item or device that can cause laceration or puncture wounds: e.g. needles, cannulae, scalpels and lancets. |
| Significance (statistical) | A result is deemed statistically significant if the probability of the result occurring by chance is less than 1 in 20 (p <0.05). |
| Single-use | The medical device/item/equipment is intended to be used on an individual patient during a single procedure and then discarded. The device is not intended to be reprocessed or reused. |
| Single-patient use | Items that can be used several times but are reserved for the use of one patient only. |
| Skin tunnelled catheter | Vascular access device whose proximal end is tunnelled subcutaneously from the insertion site and brought out through the skin at an exit site. The tip of the catheter lies in the lower third of the superior vena cava. |
| Stakeholder | Those with an interest in the use of the guideline. Stakeholders include manufacturers, sponsors, healthcare professionals, and patient and carer groups. |
| Sterile | Free from any living microorganisms, eg, sterile gloves, sterile catheter. |
| Sterile technique | A technique that prevents any possibility for the transmission of microorganisms. |
| Substantivity | Substantivity is an attribute of certain active ingredients that adhere to the stratum corneum (ie, remain on the skin after rinsing or drying) to provide an inhibitory effect on the growth of bacteria remaining on the skin. |
| Suprapubic catheter/catheterisation | Suprapubic catheterisation creates a tunnel from the abdominal wall to the bladder. Urine can then be drained directly from the bladder into a bag through a catheter inserted into this tunnel. |
| Symptomatic UTI | An urinary tract infection causing symptoms which may include: dysuria, loin pain, supra pubic tenderness, fever, pyuria and confusion. |
| Systematic review | Research that summarises the evidence on a clearly formulated question according to a pre-defined protocol using systematic and explicit methods to identify, select and appraise relevant studies, and to extract, collate and report their findings. It may or may not use statistical meta-analysis. |
| Time horizon | The time span over which costs and health outcomes are considered in a decision analysis or economic evaluation. |
| Transient microorganisms | Micro-organisms acquired on the skin through contact with surfaces. The hostile environment of skin means that they can usually only survive for a short time, but they are readily transferred to other surfaces touched. These can be removed by washing with soap and water or inactivated by alcohol handrub and antiseptic agent. |
| Transparent semipermeable membrane (TSM) dressing | Adhesive sterile dressing that allows the passage of water vapour and oxygen but is impermeable to water and micro-organsims, usually transparent to allow visual inspection of the skin/site. |
| Treatment allocation | Assigning a participant to a particular arm of the trial. |
| Univariate | Analysis which separately explores each variable in a data set. |
| Urethral | Relating to the tube that conveys urine from the bladder to the external urethral orifice. |
| User preference | The preferred technique or product used by the clinician/patient/carer. |
| Utility | A measure of the strength of an individual’s preference for a specific health state in relation to alternative health states. The utility scale assigns numerical values on a scale from 0 (death) to 1 (optimal or ‘perfect’ health). Health states can be considered worse than death and thus have a negative value. |
| VAD related blood stream infection | See ‘CRBSI’. |
| VAD related local infection | See ‘VAD related soft tissue infection’. |
| VAD related phlebitis | Inflammation of the vein, may be accompanied by pain, erythema, oedema, streak formation and/or palpable cord associated with an indwelling VAD. |
| VAD related skin infection | See VAD related soft tissue infection. |
| VAD related soft tissue infection | Presence and growth of a pathogenic micro-organism in the soft tissue around the entry site of a VAD or along the length of a skin tunnelled catheter with signs of infection/inflammation indicated by pain, redness, immobility (loss of function), swelling and heat. |
| VAD related thromobophlebitis | Inflammation of the vein in conjunction with the formation of a blood clot in associated with an indwelling VAD. |
| Visibly soiled hands | Hands showing visible dirt or visibly contaminated with proteinaceous material, blood, or other body fluids (e.g. fecal material or urine). |
| Visual Infusion Phlebitis (VIP) score | A tool for monitoring intravenous infusion sites and determining when access should be removed. |
| Washout(s) | See ‘Bladder washout’. |
