Data completeness bias
Using a computer decision support system (CDSS) to log episodes in the intervention group and using a manual system in the non-CDSS control group can create variation in the completeness of data. See also Bias.

Data-dredging
Searching a data set for differences between groups on particular outcomes, or in subgroups of patients, without explicit a priori hypotheses.

de Musset head-bobbing sign
A peripheral hemodynamic sign traditionally associated with aortic regurgitation. The de Musset head-bobbing sign consists of a forward shaking of the head with every heartbeat. It is best observed in patients who are sitting.

Death rattle
Sign of retained respiratory secretions displayed by many dying patients.

Decision aid
A tool that endeavors to present patients with the benefits and harms of alternative courses of action in a manner that is quantitative, comprehensive, and understandable.

Decision analysis
A systematic approach to decision making under conditions of uncertainty. It involves identifying all available alternatives and estimating the probabilities of potential outcomes associated with each alternative, valuing each outcome, and, on the basis of the probabilities and values, arriving at a quantitative estimate of the relative merit of the alternatives.

Decision tree
Most clinical decision analyses are built as decision trees, and the articles usually will include one or more diagrams showing the structure of the decision tree used for the analysis.

Decisional Conflict Scale
An instrument for measuring difficulties in end-of-life decision making related to interpersonal conflict. For more information, see the following article for the scale: O’Connor AM. Validation of a decisional conflict scale. Med Decis Making. 1995;15(1):25-30. [PMID: 7898294]

Deglutition disorders
Disorders that cause difficulty swallowing.

Degrees of freedom
A technical term in a statistical analysis that has to do with the power of the analysis. The more degrees of freedom, the more powerful the analysis. The degrees of freedom typically refers to the number of observations in a sample less the number of unknown parameters estimated for the model. It reflects a sort of adjusted sample size, with the adjustment based on the number of unknowns that need to be estimated in a model. For example, in a 2-sample t test, the degrees of freedom is n1 + n2 – 1 – 1, because there are n1 + n2 subjects altogether and 1 mean estimated in one group and 1 mean in another, giving n1 + n2 – 2.

Delirium
A syndrome composed of disturbances of consciousness (ie, arousal), attention, and cognition with abrupt onset and fluctuating course and that are etiologically related to medical causes.

Delirium Rating Scale–Revised-98
A 16-item clinician-rated scale with 13 severity items and 3 diagnostic items for measuring delirium severity. For more information, see the following article for the scale: Trzepacz PT, Mittal D, Torres R. Validation of the Delirium Rating Scale-Revised-98: comparison with the Delirium Rating Scale and the Cognitive Test for Delirium. J Neuropsychiatry Clin Neurosci. 2001;13:2:229-242). [PMID: 11449030]

Delirium, hyperactive
Delirium commonly characterized by restlessness, agitation, hypervigilance, hallucinations, and delusions.

Delirium, hypoactive
Delirium that includes psychomotor retardation, lethargy, and reduced awareness of surroundings. It is often mistaken for depression and is difficult to differentiate from sedation because of opioids or obtundation in the last days of life.

Delirium, mixed
A subtype of delirium with periods of hypoactivity and sedation alternating with periods of hyperactivity and agitation.

Dementia
A progressive condition marked by development of multiple cognitive deficits that include memory impairment and at least 1 of the following cognitive disturbances: agnosia, aphasia, apraxia, or a disturbance in executive functioning.

Deontological
A deontological approach to distributive justice holds that the clinician’s only responsibility should be to best meet the needs of the individual under his or her care. An alternative to the consequentialist or utilitarian view.

Depersonalization
A clinician’s detachment from his/her job.

Depression
A mood disorder marked by sadness, inactivity, difficulty with thinking and concentration, a significant decrease (or increase) in appetite and time spent sleeping, feelings of dejection and hopelessness, and sometimes suicidal thoughts or an attempt to commit suicide.

Detection bias
The tendency to look more carefully for an outcome in one of the comparison groups. Also known as surveillance bias. See also Bias.

Determinants of outcome
The causal factors that most strongly determine whether or not a target event will occur.

Dialysis
A medical procedure used in a patient with renal failure to remove wastes or toxins from the blood and to adjust fluid and electrolyte imbalances by using a semipermeable membrane.

Dichotomous outcome
A categorical variable that can take one of two discrete values rather than an incremental value on a continuum (eg, pregnant or not pregnant, dead or alive).

Dichotomous variable
A variable that can take one of two discrete values rather than values incrementally placed along a continuum (eg, male or female, pregnant or not pregnant, dead or alive).

Differential diagnosis
The set of diagnoses that can plausibly explain a patient’s presentation. See also Active alternatives.

Differential verification bias
When test results influence the choice of the reference standard (eg, test-positive patients undergo an invasive test to establish the diagnosis, whereas test-negative patients undergo long-term follow-up without application of the invasive test), the assessment of test properties may be biased. See also Bias; Verification bias.

Dignity therapy
In dignity therapy, patients dying of any cause and thought to be within the last 6 months of life are asked to speak on tape about various aspects of life they would most want permanently recorded and ultimately remembered. (See also Chapter 27, Dignity-Conserving Care—A New Model for Palliative Care.)

Dignity-Conserving Model of Care
Theoretical model describing methods of preserving a patient’s dignity at the end of life. (See also ABCD framework for details and Chapter 27, Dignity-Conserving Care—A New Model for Palliative Care.)

Dignity-conserving repertoire
The dignity-conserving repertoire incorporates those aspects of patients’ psychological and spiritual landscape that influence their sense of dignity. This is often based on preexisting personality characteristics and on internal resources that patients bring to their illness experience. (See also Chapter 27, Dignity-Conserving Care—A New Model for Palliative Care.)

Dipstick urinalysis
A chemical analysis of urine performed by using urine dipsticks, in which the test results can be read as color changes.

Disability-adjusted life-years
The number of years of life after downward adjustment for disabilities that patients experience. See also Quality-adjusted life-year.

Disabled persons
People with impairments in body function or structure.

Discriminant analysis
A statistical technique, similar to logistic regression analysis, that identifies variables that are associated with the presence or absence of a particular categorical (nominal) outcome.

Discrimination, social
Poor or inferior treatment of a person of a certain group based solely on class or social factors.

Disease-specific health-related quality of life
Disease-specific HRQL measures evaluate the full range of patients’ problems and experiences relevant to a specific condition or disease. See also Health-related quality of life.

Do-not-attempt-resuscitation (DNAR) order
A legal document that states resuscitation should not be attempted if a person experiences a respiratory or cardiac arrest. The “A” for attempt was added to “do not resuscitate” so that it is not presumed by the patient or family that an attempt at resuscitation would be successful.

Do-not-resuscitate (DNR) order
A legal document that states that resuscitation should not be attempted if a person experiences a respiratory or cardiac arrest.

Do-not-resuscitate–do-not-intubate (DNR/DNI) order
A legal document that states that resuscitation should not be attempted if a person experiences a cardiac or respiratory arrest and includes the specific clarification that the person should not be intubated, although in some hospitals a DNR order alone implies no intubation.

Document analysis
In qualitative research, this is one of 3 basic data collection methods. It involves the interpretive review of written material.

Dominant
Describes any trait that is expressed in a heterozygote, ie, one copy of that allele is sufficient to manifest its effect.

Dominate
In economic evaluation, if the intervention of interest is both more effective and less costly than the control strategy, it is said to dominate the alternative.

Dose-response gradient
Exists when the risk of an outcome changes in the anticipated direction as the quantity or the duration of exposure to the putative harmful or beneficial agent increases.

Double effect
The traditional justification for proportionate palliative sedation is the doctrine of double effect, which draws a moral distinction between what a person intends in taking an action (eg, in administering an opioid) and what is accepted as a possibly foreseen but unintended adverse effect related to that action (eg, dose-related slowing of respirations).

Downstream costs
Costs due to resources consumed in the future and associated with clinical events in the future that are attributable to the intervention.

Drug class effects
Similar effects produced by most or all members of a class of drugs (eg, beta blockers, calcium antagonists, or angiotensin converting enzyme inhibitors).

DSM-IV-TR
Published by the American Psychiatric Association, the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) provides common terms and specific criteria for the classification of mental disorders.

Durable power of attorney (DPOA)
An advance directive that empowers a proxy to make decisions for the grantor should he/she become incapacitated.

Durable power of attorney for health care (DPOA-HC)
A type of advance directive that names a proxy to make health care decisions should the patient be incapacitated based on the patient’s best interests, preferably based on the patient’s previously expressed wishes.

Durable power of attorney for legal and financial transactions
A type of advance directive that names a proxy to make legal and financial decisions should the patient be incapacitated based on the patient’s best interests, preferably based on the patient’s previously expressed wishes.

Dyspepsia
Indigestion. Functional dyspepsia is pain or discomfort centered in the epigastrium with a normal endoscopy.

Dysphagia
Difficulty in swallowing.

Dyspnea
Difficulty breathing or labored breathing.

Dysuria
Painful urination.