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At least 19 recordsLinked to original sources

Cyclosporine monitoring in renal transplantation: area under the curve monitoring is superior to trough-level monitoring.

Trough levels (TL) of cyclosporine (CS) measured in serum by the polyclonal radioimmunoassay (SR) are useful for dissecting the etiology of clinical events, but they are a poor guide to dosage adjustments. In renal transplant patients immunosuppressed by low doses of prednisone and CS given orally, once-a-day TL (24-h) monitoring was replaced by area under the curve (AUC) monitoring, i.e., measuring the area under the concentration (SR)-time curve from seven blood samples (0, 2, 4, 6, 10, 14, and 24 h) at clinical steady state, which was reached on the 3rd day after a change in the oral dose rate. The therapeutic target was an average concentration at steady state (Css av) of 200 ng/ml during the first 6 months after transplantation and 150 ng/ml thereafter. The Css av was calculated by dividing the AUC by the dosing interval (24 h). Two findings demonstrated the superiority of AUC monitoring over TL monitoring. First, in 71 paired observations AUC but not TL was significantly correlated with the dose expressed as total mg (r = 0.381, p = 0.001) or mg/kg body weight (r = 0.538, p = 0.0001). Second, after adjusting (n = 26) the oral dose rate (to achieve the therapeutic target) the absolute error (i.e., deviation from the target) in the AUC observation (15%) was significantly (p = 0.0005) smaller than in the TL observation (36%). Monitoring AUC at clinical steady state reduced the number of dosage adjustments by a factor of 3.

Cyclosporins

Assessment of compliance with home cardiorespiratory monitoring in infants at risk of sudden infant death syndrome. Collaborative Home Infant Monitoring Evaluation (CHIME).

OBJECTIVES: Documented monitoring was used to evaluate prospectively (1) the level of compliance among infants in whom cardiorespiratory monitoring was clinically indicated and (2) factors that might influence compliance: diagnosis, socioeconomic status, maternal age and education, and alarms. STUDY DESIGN: Sixty-seven infants (51% female, 49% term) were sequentially enrolled, and monitoring was prescribed for the following indications: siblings of sudden infant death syndrome victims (16%), apnea of prematurity (45%), and apparent life-threatening events or apnea of infancy (39%). Demographic data, alarm and event data, and a summary report of monitor use from the first monitor download were obtained. RESULTS: Maternal age, education, and insurance status did not differ significantly by indication for monitoring. The median number of monitor alarms per 10 hours of use was 0.7 for apnea or bradycardia and 0.6 for loose lead alarms. Monitors were available for use in the home from 2 to 106 days (median, 11 days). Median hours of monitor use per full day in the home was 15.5 hours. Of 67 infants, 58 used the monitor for at least part of every day in the home. The number of hours of monitor use per day did not differ significantly by diagnostic category, chronologic age, alarms, maternal age, education, or insurance type. This study population of infants at increased risk of sudden infant death syndrome had excellent compliance; 75% of the infants were monitored more than 10.5 hours per day, and 25% were monitored more than 21 hours per day. CONCLUSIONS: Documented monitoring provides an objective measure of compliance. These data provide a potential goal for level of compliance with home cardiorespiratory monitoring.

Analysis of Variance

Do we monitor enough? We don't monitor enough.

The choice of which intraoperative monitors to use for routine cases is difficult, because a multitude of monitors is available today. Monitoring is deemed necessary to avoid problems, although there is little hard evidence that a specific monitor will improve outcome. The risk associated with modern noninvasive monitors, however, is negligible, and they should be considered for routine use in all patients. Although errors in the variables displayed or misuse of correct information can cause difficulties, these result from a lack of education and are not a valid reason to abandon a particular monitoring modality. Regular use of such monitoring tools as the electroencephalogram would allow clinicians to become familiar with how to interpret it in normal and crisis situations. The cost of a disaster during anesthesia (such as unrecognized hypoxia) is high. The dollars spent to cover a single major malpractice award could buy a tremendous number of monitors. The state of the art in the mid-1980s demands traditional anesthesia monitors plus continuous capnography and measurement of peripheral oxygenation. Other negligible-risk monitors should also be used when feasible. Improvement in monitoring design, particularly in output formats and in integration of monitored data, will be essential in the next few years, as will training in the proper use of monitors.

Electrocardiography

Elevated blood pressure during the first two hours of ambulatory blood pressure monitoring: a study comparing consecutive twenty-four-hour monitoring periods.

OBJECTIVE AND DESIGN: Ambulatory blood pressure monitoring is being used increasingly in clinical practice and hypertension research. We have noted elevated blood pressure during the initial hours of monitoring. The objective of the present study was to examine the consistency, magnitude and duration of this elevation, and to determine whether this effect causes significant differences in the mean ambulatory blood pressure monitoring values comparing the first (day 1) and second (day 2) consecutive 24-h periods of monitoring. METHODS: Fifty patients who were hypertensive based on repeated clinic readings were studied prospectively. Each underwent continuous 48-h ambulatory blood pressure monitoring with a SpaceLabs 90207 monitor. The device recorded blood pressure at 15-min intervals during the daytime (0600-2159 h) and at 30-min intervals at night-time (2200-0559 h). From these readings hourly means were calculated. Repeated-measures analysis of variance was performed to compare the hourly means of days 1 and 2. RESULTS: Repeated-measures analysis of variance indicated that a significant difference existed for both systolic and diastolic blood pressure between day 1 and day 2. Paired Student's t-test revealed that this difference occurred during the first 2 h of monitoring. The daytime blood pressure was higher on day 1 as a result of the initial elevation of blood pressure at the onset of monitoring. The initial elevation of blood pressure was present both in white-coat hypertensives and in essential hypertensives. CONCLUSION: The first 2 h of ambulatory blood pressure monitoring are associated with elevated blood pressure both in white-coat hypertensives and in essential hypertensives. This has a minor effect on mean daytime and 24-h ambulatory blood pressures. We propose that improved ambulatory blood pressure monitoring recordings would be obtained in clinical practice, and more particularly in research applications, if 26-h ambulatory blood pressure monitoring was carried out, excluding the first 2 h from the summary analyses.

Adult

The computer-based anesthetic monitors: the Duke Automatic Monitoring Equipment (DAME) system and the microDAME.

From 1972 to 1983 the Duke University Department of Anesthesiology designed, built, and maintained most of its own operating room patient monitoring equipment. Construction of a new hospital facility in 1980 provided the opportunity to design and test a new computer-based system, the Duke Automatic Monitoring Equipment (DAME) System. The system consist of microcomputer-based instrumentation on monitoring carts, which communicate with a central minicomputer that allows selection of different software monitoring packages based on the needs of the patient. Multiple problems, including frequent total monitoring failures during surgery, plagued the DAME System in its first year of operation. Despite resolution of many of these problems, user acceptance was poor because of the large size and weight of the monitoring carts, the inadequate quality of displayed physiological waveforms, and inability to overcome the difficulties of the man-machine interface. Because the remaining problems could not be rectified with the existing monitoring carts, a new generation of monitors was designed. The smaller, multiprocessor microDAME was designed to be as automatic and user tolerant as possible. It would omit much of the flexibility that had proved undesirable in the DAME system. When the microDAME was nearly completed, however, departmental research in that area ceased. It remains for others to apply our experiences to further improve operating room patient monitors.

Anesthesiology

Guidance of visual reaching with the aid of a TV monitor: the effects of monitor position and of left/right and up/down reversals of the image in relation to age.

Children, aged 2-9 years, were seated alongside a wall containing an opening through which they could reach with their preferred hand. Targets ("ink blots"), which could not be felt, were attached to the other (rear) side of the wall, around the opening. The child could see directly neither the target nor its hand beyond the front side of the wall; but both were visible on a TV monitor. The image on the screen of the monitor originated from a camera viewing the rear (target) side of the wall at the level of the central opening. The monitor screen was either (a) parallel to the wall, but rotated 180 degrees with respect to the axis of the camera, i.e. facing the camera; or (b) at 90 degrees to the wall; or (c) in a position similar to (a) but visible in a mirror attached to the front side of the wall and therefore in effect "aligned" with the axis of the camera. The image the child saw was either (1) electronically unswitched, i.e. when the target was towards the east on the wall it was to the west on the monitor in monitor position (a), or to the north in position (b), or to the "east" in position (c); or (2) left/right reversed relative to (1); or (3) up/down reversed relative to (1); or (4) both left/right and up/down reversed. The dependent variable was the time taken for the child to place the palm of the hand over the target (time was measured to 0.1 sec on video-recorder with a superimposed time display). Position of the monitor, comparing conditions (a)-(c), gave only minor, perhaps age-related, effects. Left/right reversals were easier than up/down reversals under monitor positions (a) and (b), but not under (c); but both reversals could be achieved by age 3 or older; hardest was condition (4). However, with monitor positions (a) and (b) children, at all ages we tested, found condition (1) ("east gives west/north") easier than (2) ("east gives east/south"), whereas for adults these conditions were equally easy, or they found (2) easier than (1); but with monitor position (c) condition (1), now "east gives east", was easiest. Moreover, the claim that chimpanzees but not monkeys can achieve accurate reaching under the conditions varied in this study seems premature: the chimpanzees may have made use of strategies based on uncontrolled cues.

Attention

Do we monitor enough? We monitor too much.

Not only may we monitor too much, we also may monitor improperly. By so doing we divert attention from the patient and the anesthetic and thereby often decrease the quality of care. Furthermore, the teaching of residents can be impeded by an overemphasis on monitoring, resulting in a wrong sense of values. The cost of monitoring is high, not only in financial terms, but also in terms of the time devoted to machines, electrodes, and sensors, and in terms of complications such as shearing, infections, vasospasm, hematomas, and even fatal hemorrhage. Not all monitoring is bad, however. Oxygen, temperature, blood pressure, and the electrocardiogram should be monitored, but we must avoid a lavish concept that monitoring will solve all our problems and eliminate the need for proper personal attention. Most important, we must avoid the notion that more monitoring is categorically better.

Anesthesia, General

Ambulatory blood pressure monitoring during pregnancy with a new, small, easily concealed monitor.

Before establishing the utility of ambulatory blood pressure monitoring during pregnancy, we evaluated the accuracy of a small, easily concealed monitor. The 59 normotensive pregnant patients were between 13 and 26 gestational weeks. For each monitor reading, two trained observers independently and simultaneously recorded blood pressures using a mercury manometer connected to the monitor cuff. Seven readings in three positions (sitting upright, semirecumbent, standing) were performed on each patient. Averaged differences between the observers' and monitor readings varied from -2.2 to -0.9 mm Hg (systolic) and from -2.8 to -0.6 (fifth-phase diastolic), indicating slight but clinically unimportant overestimation by the monitor. Correlations between averaged observers' readings and the monitor ranged from 0.79 to 0.92 (systolic) and from 0.85 to 0.92 (fifth-phase diastolic). Overall, the observers agreed with the monitor within 5 mm Hg on 94% of systolic readings and 99% of fifth-phase diastolic readings. There was no statistically significant difference in accuracy with changes in body position. We conclude that this small, quiet, noninvasive device accurately determined blood pressures during pregnancy.

Adolescent

Anesthetic mishaps and the cost of monitoring: a proposed standard for monitoring equipment.

Review of insurance data indicates that approximately 1.5 claims are paid per 10,000 anesthetic procedures, a conservative estimate of the incidence of preventable serious injury associated with anesthesia. Insurance data permit estimation of the premium cost for the anesthesiologist and hospital, per operating room per year, of $69,429.00. We propose the use of an enhanced monitoring standard requiring a pulse oximeter, capnograph, spirometer, halometer, automatic sphygmomanometer, breathing circuit oxygen analyzer, stethoscope, electrocardiographic monitor, and temperature monitor. We suggest that this premium cost, together with the estimate that 50% of incidents would be avoided, predicts a resultant saving of over $27,000/operating room/year, a savings equal to the entire cost of the enhanced monitoring system in approximately 8 months, or a yearly savings of over five times the annualized expense of the monitoring system. Thus, in addition to the moral imperative to monitor a patient during anesthesia to avoid injury and death, there is an economic incentive to monitor effectively.

Anesthesia

Home monitoring of warfarin therapy in children with a whole blood prothrombin time monitor.

We prospectively evaluated a capillary whole blood prothrombin time (PT) monitor (Biotrack, Ciba Corning) in an outpatient pediatric anticoagulation clinic (40 clinic patients) and in age-matched healthy subjects (30 control subjects). Subsequently, 23 children requiring warfarin therapy were placed on a home program (home patients) using the PT monitor; their parents were trained and the results followed by clinic staff. The PT results were reported as internationalized normalized ratios (INRs). The laboratory and PT-monitor INR values were similar for the clinic patients and the control subjects (y = 0.76x + 0.38; r = 0.93; p < 0.001). The accuracy of the PT monitor (the difference between INR values and the laboratory INR) was best at an INR of 2.5 to 3.5; 90% of paired INR values were within 0.8 INR units. The average duration of monitoring for home patients was 13 months (range, 2 to 60 months). They had an average of 3 dose measurements (range, 1 to 11 measurements) and 1.8 dose changes (range, 0.6 to 4.5 changes) per month. Of the 599 measurements, 63% were within the therapeutic range, similar to those for clinic patients; the dose requirements were also similar. There was 1 significant bleeding event, a subdural hematoma in a patient with an INR of 4.1, and 1 catheter-related thrombotic event with an INR of 1.2; both children recovered. Of the 23 families, one discontinued home monitoring because of parental discomfort, 2 children died of their primary disease, 6 completed warfarin therapy, and 14 remain on the home program. We conclude that the whole blood PT/INR monitor is safe and offers practical advantages to children requiring anticoagulation.

Adolescent

A consensus view on the technique of ambulatory blood pressure monitoring. The Fourth International Consensus Conference on 24-Hour Ambulatory Blood Pressure Monitoring.

This review, based on the Fourth International Consensus Conference on Ambulatory Blood Pressure Monitoring (Leuven, Belgium, 1994), deals with the technical aspects of ambulatory blood pressure monitoring. Ambulatory blood pressure monitoring by noninvasive intermittent techniques is widely used despite artifacts due to cuff size, movement, body position, short-term blood pressure variability, and interference with sleep. The performance of the currently available monitors under truly ambulatory conditions and during exercise remains a matter of debate, as are the procedures required to validate portable monitors under these circumstances. There is general agreement that whenever a monitor is to be used in special populations, such as older subjects or pregnant women, or in special conditions, such as exercise, a specific demonstration of its accuracy in these defined subgroups or conditions is warranted. Whether the auscultatory or oscillometric method is preferred remains controversial because each technique has specific advantages and disadvantages and because both can provide accurate results. Most experts in the field strongly believe that manufacturers should disclose the algorithms of their devices and that they should specify all changes made to the hardware and software of a previously validated monitor. Finally, the development of the volume-clamp method, which makes continuous noninvasive registration of blood pressure at the finger possible in both stationary and ambulatory conditions, opens new perspectives in research, in particular in relation to short-term blood pressure variability.

Adult

Home monitoring of gonadotropin ovulation induction using the Ovarian Monitor.

The safe use of gonadotropins relies on close hormonal and/or ultrasound monitoring to assess the response to treatment, requiring multiple hospital visits. Home monitoring with the Ovarian Monitor (St. Michael Research Foundation, Macleod, Victoria, Australia) minimizes hospital visits and overcomes many of the logistic difficulties associated with gonadotropin use. It utilizes a system of homogenous enzyme immunoassay using lysozyme conjugates to measure quantitatively either urinary estrone-3 or pregnanediol-3-glucuronide. Results obtained by 24 patients in 57 cycles using the Ovarian Monitor at home correlate closely with results obtained in the laboratory (estrone-3-glucuronide r = 0.955; pregnanediol-3-glucuronide r = 0.958). Cycle outcomes (ovulation, 74%/cycle; clinical pregnancy, 30%/cycle; multiple pregnancy, 13%/pregnancy; hyperstimulation, 11%/cycle) are no different from those achieved in laboratory-monitored patients. Home monitoring can be as safe and effective as laboratory monitoring, offers significant social benefits, and improves access to this form of therapy.

Adult

Comparative accuracies of a finger blood pressure monitor and an oscillometric blood pressure monitor.

A noninvasive blood pressure monitor (Finapres) that uses the methodology of Penaz to continuously display the arterial waveform from the finger has been introduced recently. The Finapres monitor overestimated systolic pressure by 5.8 +/- 11.9 mm Hg, while the Dinamap monitor underestimated systolic pressure by -6.9 +/- 9.2 mm Hg (P = 0.003). Dinamap mean and diastolic pressure biases were less than 2 mm Hg, while the Finapres biases for these variables were significantly greater (7.7 +/- 10.0 and 8.2 +/- 9.8 mm Hg, respectively). There was no difference in systolic or mean pressure precision between the two devices (approximately 10 mm Hg), but the diastolic precision of the Dinamap unit was superior to that of the Finapres. While in most patients the Finapres monitor provided continuous blood pressure data equivalent to the data from the radial artery, marked bias (greater than 15 mm Hg) was exhibited in 2 patients for all three pressure variables. Despite this bias, blood pressure changes were tracked closely in these 2 patients. We conclude that, in its current form, the Finapres monitor cannot be relied upon independently to accurately measure blood pressure in patients undergoing general anesthesia. Since the Dinamap monitor measures mean pressure reliably and accurately, we suggest that mean blood pressure values between the Finapres and Dinamap monitors be compared to guide one in interpreting Finapres data.

Adolescent

Significance and incidence of concordance of drug efficacy predictions by Holter monitoring and electrophysiological study in the ESVEM Trial. Electrophysiologic Study Versus Electrocardiographic Monitoring.

BACKGROUND: Selection of antiarrhythmic therapy may be based on either suppression of spontaneous ventricular arrhythmias assessed by Holter monitoring or by suppression of inducible ventricular arrhythmias during electrophysiological study. This study examines the frequency and significance of concordance of these two approaches in the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial. METHODS AND RESULTS: Twenty-four-hour Holter monitoring was performed in patients randomized to the electrophysiology limb of the ESVEM study at the time of the first drug trial and at the time of an effective drug trial. Holter monitors were available in 65% (146/226) of patients at the time of the first drug trial and in 93% (100/108) of patients at the time of an electrophysiology study predicting drug efficacy. There were no clinical differences between patients who had and those who did not have a Holter monitor. At the time of the first drug trial, concordance of Holter and electrophysiological predictions of drug efficacy was observed in 46% of patients (both techniques predicted efficacy in 23%; neither predicted efficacy in 23%). Discordant results were observed in 54% (Holter suppression without electrophysiological suppression in 44%; electrophysiological suppression without Holter suppression in 10%). At the time of an electrophysiology study predicting drug efficacy, 68 of the 100 patients without inducible ventricular tachyarrhythmias also had suppression of spontaneous ventricular arrhythmias on the Holter recorded at the time of the electrophysiological study. Neither arrhythmia recurrence nor mortality was significantly different in patients with suppression of both inducible and spontaneous ventricular arrhythmias compared with those with only suppression of inducible arrhythmias. Comparison of patients with suppression of both inducible and spontaneous ventricular arrhythmias with the 188 patients in the Holter limb, in whom efficacy was predicted by Holter monitoring only, revealed no difference in outcome. CONCLUSIONS: In this population, (1) there is frequent discordance in prediction of drug efficacy and inefficacy between electrophysiological study and Holter monitoring; (2) a requirement to fulfill both Holter and electrophysiological efficacy criteria reduces the number of patients with an efficacy prediction; and (3) suppression of both spontaneous ventricular ectopy and inducible ventricular tachyarrhythmias does not identify a group with better outcome.

Aged

Intracranial pressure monitoring: fiberoptic monitor compared with the ventricular catheter.

Among the frequently utilized intracranial pressure (ICP) monitoring devices employed in neurosurgical practice is the Camino fiberoptic monitor. Several recent studies have described results with the Camino monitor and compared it with other forms of ICP monitoring with varying results and conclusions. The aim of this study was to compare simultaneous ICP readings from the Camino fiberoptic monitor placed in the brain parenchyma and from a ventricular catheter. ICP values were recorded for up to 118 hours in 10 patients. It was determined that the Camino ICP measurements exceeded those of a ventricular catheter in 66% of total measurements for the 10 patients. The mean ICP difference between the Camino fiberoptic system and the ventricular catheter was 9.2 +/- 7.8 mm Hg. This result suggests that the correlation between intraparenchymal pressure measured by the Camino fiberoptic monitor and the intraventricular pressure is not as close as previously described.

Catheterization