Contrast patient-related factor

Patient-Related Factors 98 .2.2 Contrast Injection Parameters .2.3 CT Parameters 101... 

The two relevant patient-derived factors that affect contrast enhancement are body weight and cardiac output (or cardiovascular circulation time). All other patient-related effects on contrast attenuation are negligible. 

Many patient-related and injection-related factors can affect the magnitude and timing of intravenous contrast agent attenuation. A cross-linked network interrelates all of these factors, but they may be grossly separated into two categories (1) factors that predominantly affect the magnitude of contrast attenuation (body size, contrast volume, iodine concentration and sahne flush) and (2) factors that predominantly affect the temporal pattern of contrast attenuation (cardiac output, contrast injection duration and contrast injection rate). 

Critically ill patients are frequently scanned using CT, and in many cases witii administrations of contrast agent. Many of these patients have factors that are considered to be risks for CIN development. Yet, these patients are also at risk of renal injury from other factors related to their illness. A prospective matched cohort study compared 53 pairs of critically ill patients. Fourteen contrast and 19 noncontrast patients had a decline of at least 33% of creatinine clearance levels, and a 50% reduction of creatinine clearance which persisted 3 days after contrast in three contrast and nine noncontrast patients. The study concludes tirat decline in creatinine clearance levels in critically ill patients, although commonly seen after contrast enhanced CT, are likely to be attributed to other factors other than the administration of tire contrast agent [25 j. 

Disturbances of sleep are typical of mood disorders, and belong to the core symptoms of major depression. More than 90% of depressed patients complain of impaired sleep quality [60], Typically, patients suffer from difficulties in falling asleep, frequent nocturnal awakenings, and early morning awakening. Not only is insomnia a typical symptom of depression but, studies suggest, conversely, insomnia may be an independent risk factor for depression. In bipolar disorders sleep loss may also be a risk factor for the development of mania. Hypersomnia is less typical for depression [61] and, in contrast to insomnia, may be related to certain subtypes of depression, such as seasonal affective disorder (SAD). 

As in any safety evaluation, the planned work should be related to the intended use and treatment of humans, for example one dose in a few gravely ill patients or multiple doses of the entire healthy community as prophylaxis against a trivial condition. Contrast, say, what might be appropriate for tumor necrosis factor, as in an experimental trial in a few sufferers from late-stage cancer, with the requirements... 

Another perspective comes from famiiy systems theory, which characterizes the schizophrenic patient s family as having disordered communication, with various members playing unusual or aberrant roles. According to this theory, patients experience double binds when faced with contradictory expectations ( 7). Related controversial hypotheses held that the schizophrenogenic mother was the critical factor and then later that the schizophrenic s father also played a significant role (8, 9 and 10). Intensive therapy, in the context of in-hospital separation from the family, was considered the treatment of choice. In contrast to classic psychodynamic therapy, which focuses on the individual patient, this approach attempts to resolve conflicts in the family system, as well as in the patient s psyche. Typically, this involves sessions that include all or as many members as possible. Thus, even though one member is identified as the patient, it is the disturbed communication and interactions among all members that is the focus of therapy. This and subsequent therapeutic approaches may be most effective when medication is used concurrently. 

All patients admitted to a hospital during 6 months who had taken at least one dose of metformin were retrospectively evaluated for susceptibility factors for metformin-associated lactic acidosis (8). There were 263 hospitalizations in 204 patients. In 71 admissions there was at least one contraindication, such as renal or liver disease, renal dysfunction, congestive cardiac failure, metabolic acidosis, or an intravenous iodinated contrast medium given within 48 hours of metformin. In 29 (41%) metformin was continued despite the contraindication. The most frequent contraindication was a raised serum creatinine, but in only eight of the 32 admissions was metformin withdrawn. Of nine patients using metformin who died (not necessarily directly related to metformin), six had an absolute contraindication. In two patients who died and in one who survived, blood lactate was increased and this was temporally related to the use of metformin. 

Sleep disorders are common, and are generally underdiagnosed. The two major complaints related to sleep are insomnia ( I can t sleep ) and excessive daytime sleepiness (EDS, I can t stay awake ). EDS is a relatively nonspecific symptom. It can be the end result of any factor that causes sleep disruption, and it can be caused by primary or intrinsic sleep disorders. Insomnia of any cause can result in sleep deprivation and subsequent EDS. The most common cause of EDS in the general population is self-imposed sleep deprivation, or insufficient sleep syndrome. By contrast, the most common causes of EDS seen in a sleep center are primary (intrinsic) disorders of EDS. The American Academy of Sleep Medicine (AASM, formerly the American Sleep Disorders Association) classification of sleep disorders includes over 80 diagnoses that are associated with EDS, but the majority of patients evaluated at sleep centers have sleep apnea, narcolepsy, idiopathic hypersomnia, or periodic limb movements of sleep. 

Preventing CIN is of particular importance in patients with diabetes and chronic kidney disease, as these are two of the most powerful independent risk factors for CIN (77), Diabetics are more susceptible to (CIN) than are the nondiabetics, and diabetics with pre-existing chronic kidney disease (CKD) are at even greater risk (78). In a recently proposed CIN risk-scoring system, patient characteristics such as diabetes, age >75, chronic congestive heart failure, admission with acute pulmonary edema, hypotension, anemia and chronic kidney disease and various procedure-related characteristics including increasing volumes of contrast media, and intra-aortic balloon pump use were all found to reliably contribute to increased risk (79). 

In 1798 Indian patients the prevalence of adverse reactions to high-osmolar ionic iodinated contrast media was 21% (mild 19%, moderate 1.3%, and severe 0.3%) and there was only one death. The incidence of adverse effects was significantly higher in patients with risk factors, such as a history of previous contrast reactions (46%), bronchial asthma (69%), and diabetes meUitus (60%), compared with patients with no risk factors (21%). The authors tried to throw some light on the relation between race and incidence of contrast reactions. They showed that the incidence of mild reactions in the Indian patients (19%) was significantly higher than reported in white patients (5-15%) but that there was no difference in the incidence of moderate or severe reactions between the two populations (250). 

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