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Biomedical subjects

N M Kane

Publications and source records attributed to N M Kane.

At least 19 recordsLinked to original sources
PubMed2002

Effect of propofol anaesthesia on the event-related potential mismatch negativity and the auditory-evoked potential N1.

BACKGROUND: Studies on the effects of anaesthesia on event-related potentials and long latency auditory-evoked potentials (AEP) are sparse. Both provide information on cortical processing and may have potential as monitors of awareness. We studied the effect of propofol on the event-related potential mismatch negativity (MMN) and the long-latency AEP NI. METHODS: Twenty-one patients received 1 microgram ml-1 stepped increases in the target concentration of propofol using Diprifusor until a maximum of 6 micrograms ml-1 was achieved or the patient had lost consciousness. Neurophysiological responses (MMN and N1) and the patients' level of consciousness were recorded before the administration of propofol and at a target effector site concentration of propofol of 1, 2, 3, 4, and 6 micrograms ml-1. Grand average evoked potentials were computed at baseline, before the administration of propofol (A); at the highest propofol concentration at which each patient was responsive (B); and at the concentration of propofol at which the patient became unconscious (C). RESULTS: Patients lost consciousness at different target concentrations of propofol, all being unresponsive by 4 micrograms ml-1. The response to the deviant stimuli used to elicit duration-shift MMN was significantly more negative than to the standard stimuli at A (mean difference 2.58 microV, P = 0.0011) but this difference was virtually abolished at point B, before the patients lost consciousness (mean difference 0.63 microV, P = ns). The amplitude of N1 evoked by standard stimuli was negative compared with electrical baseline at both point A (mean amplitude -3.81 microV, P < 0.001) and at point B (mean amplitude -2.2 microV, P = 0.002), but was no longer significantly different to baseline at point C (mean amplitude 0.51 microV, P = ns). The change in the mean amplitude of N1 from last awake (point B) to first unconscious (point C) was also significant (mean difference in amplitude 1.69 microV, P = 0.02). CONCLUSIONS: MMN is unlikely to be a clinically useful tool to detect awareness in surgical patients. In contrast, the loss of N1 may identify the transition from consciousness to unconsciousness and deserves further study.

Adult↗
PubMed2001

The Medicare Cost Report and the limits of hospital accountability: improving financial accounting data.

Health policy makers, legislators, providers, payers, and a broad range of other players in the health care market routinely seek information on hospital financial performance. Yet the data at their disposal are limited, especially since hospitals' audited financial statements--the "gold standard" in hospital financial reporting--are not publicly available in many states. As a result, the Medicare Cost Report (MCR), filed annually by most U.S. hospitals in order to receive payment for treating Medicare patients, has become the primary public source of hospital financial information. However, financial accounting elements in the MCR are unreliable, poorly defined, and lacking in critical detail. Comparative analyses of MCRs and matched, audited financial statements reveal long-standing problems with the MCR's data, including major differences in reported profits; variations in the reporting of both revenues and expenses; an absence of relevant details, such as charity care, bad debt, operating versus nonoperating income, and affiliate transactions; an inconsistent classification of changes in net assets; and a failure to provide cash flow statements. Because of these problems, MCR financial data give only a limited and often inaccurate picture of the financial position of hospitals. Audited financial statements provide a more complete perspective, enabling analysts to address important questions left unanswered by the MCR data. Regulatory action is needed to create a national database of financial information based upon audited statements.

Accounting↗
PubMed2000

Alternative funding policies for the uninsured: exploring the value of hospital tax exemption.

The tax exemption accorded private, nonprofit hospitals is being subjected to more scrutiny as the numbers of uninsured grow; meanwhile, charity care competes with market-driven priorities. Current public policies tie hospital tax exemption to the provision of charity care, but there is a gap in the size and distribution of values between tax exemption and the charity care that is provided. Most hospitals, in a study reported here, provided free care at a level below the value of their tax exemption, even when 50 percent of bad debt was included in the care value. However, hospitals in the poorest communities offered considerably more care than the value of their tax exemption, whereas those in wealthier communities offered considerably less. Policies at local, state, and federal levels should be designed to exert leverage on hospitals to provide free care at a level commensurate with the value of their tax exemptions.

Health Policy↗
PubMed1999

The impact of accounting and actuarial practice differences on medical loss ratios: an exploratory study of five HMOs.

This paper explores the quantitative implications of accounting differences by examining detailed cost information on five health maintenance organizations (HMOs). Standardized cost allocations and actual medical expenses were compared to those publicly reported by HMOs in medical loss ratios (MLRs) and administrative expense ratios (AERs). Differences in accounting and actuarial practices were found to have a small percentage impact on the MLR and the AER, but they accounted for a large percentage of observed differences in reported MLRs and AERs. Policies that regulate MLR floors or AER ceilings encourage HMOs to adopt accounting practices producing the most favorable ratios for regulatory purposes.

Accounting↗
PubMed1998

Quantitative electroencephalographic evaluation of non-fatal and fatal traumatic coma.

Diffuse axonal injury (DAI) is an important cause of morbidity and mortality after traumatic brain injury (TBI), and its severity is therefore a major determinant of outcome. There have been suggestions that the extent of DAI may be reflected in quantitative measures of cerebral function, including the electroencephalogram (EEG) and brain-stem auditory evoked potentials (BAEPs). It has therefore been proposed that these quantitative methods of analysis may provide objective predictors of outcome following TBI. We prospectively investigated the relationship between quantitative EEG and BAEP measures and outcome, in 60 comatose patients (47 male and 13 female; age range 1-80 years, mean 36.4) after severe, closed head injury (post-resuscitation Glasgow Coma Scale (GCS) of 8). The Spearman correlation coefficients (rs) have been calculated for quantitative EEG measures (mean regional power and interhemispheric coherence) and BAEPs with patient outcome on the Glasgow Outcome and Disability Rating Scales at 6 months and 1 year. The measures most significantly correlated with outcome (P < 0.001) are over the left hemisphere, beta activity power (amplitude squared) in the fronto-central and centro-temporal regions, and alpha activity power in the centro-temporal region. We found no correlation between interhemispheric coherence (a statistical measure of cross-correlation in the frequency domain) and outcome at either 6 months or 1 year post-injury. In 10 fatalities, we examined the relationship between interhemispheric EEG coherence prior to deaths and the histopathological severity of DAI, in concordant regions. The only significant correlation between DAI and interhemispheric coherence is seen in the alpha band at the temporo-occipital site (rs = -0.79, P = 0.007). Our data indicate that there is regional information in EEG power spectra over the left hemisphere, which could be used in prognostic predictions for patients in coma after severe TBI. We were unable to demonstrate a correlation between interhemispheric coherence and outcome, or any clear and consistent evidence of a relationship between interhemispheric coherence and the severity of DAI.

Adolescent↗
PubMed1997

Pharmaceutical cost containment and innovation in the United States.

In the United States, government has played a limited role in containing the costs of pharmaceuticals. There are no price controls, no national drug formularies, no universal cost-sharing policies, and perhaps most important, no national coverage of prescription drugs. Rather, pharmaceutical cost containment was historically left to private insurers and managed care companies, while consumers paid out of pocket for close to 62% of all drug expenditures. US utilization has historically been relatively low and prices by far the highest of the four industrialized countries. The major change in pharmaceutical cost containment in the 1990s has been the consolidation of purchaser power at the level of the insurer and managed care companies. These 'whole sale' purchasers now represent 70% of direct manufacturer sales, and they are demanding and receiving deeper price discounts. Meanwhile these same players are implementing formulary policies, utilization controls, and disease management programs, the outcomes of which have not yet been systematically evaluated. Failure to pass on savings to consumers, cost shifting by manufacturers to vulnerable consumer groups, and potential under-utilization of cost-effective drugs remain of concern.

Cost Control↗
PubMed1996

Event-related potentials--neurophysiological tools for predicting emergence and early outcome from traumatic coma.

OBJECTIVE: To determine the prognostic value of multimodal evoked potentials (EPs) and event-related (ERPs) potentials in coma (Glasgow Coma Score <8), after severe traumatic brain injury (TBI). DESIGN: Prospective, longitudinal study of neurophysiological responses recorded during traumatic coma. SETTING: Intensive Care Unit, Frenchay Hospital, Bristol, UK. PARTICIPANTS: Fifty-four comatose TBI patients (age range 1-80 years, mean 36.4). METHODS: Neurophysiological responses were recorded from 11 scalp electrodes with earlobe reference. Conduction times were measured for brainstem auditory, flash visual and somatosensory, short-latency EPs. Peak latencies and amplitudes were determined for long-latency components of visual and auditory ERPs, generated by passive "oddball" paradigms. These neurophysiological and various clinical parameters were correlated with patient outcome using Pearson's coefficient. MAIN OUTCOME MEASURE: Three month Glasgow Outcome Scale (GOS). RESULTS AND CONCLUSION: Highly significant (P <0.001) correlations exist between long-latency ERP components and 3-month outcome. Short-latency EPs, brainstem (wave I-V) and somatosensory conduction times also correlate significantly with the GOS (P <0.01). Of the clinical measurements, pupillary response patterns, APACHE II and Glasgow Coma Scores (GCS) correlate significantly with outcome, as do the retrospective measures of duration of coma and post-traumatic amnesia (PTA) in survivors. Unfortunately, due to variance of long-latency responses, even in controls, absolute values cannot be relied upon as prognosticators. The presence of "mismatch negativity" predicted the return of consciousness (89.7% sensitivity and 100% specificity) and preceded changes in GCS. Its latency was the single best indicator of 90-day outcome from coma (r = -0.641).

Acoustic Stimulation↗
PubMed1995

Practice expenses in the MFS (Medicare fee schedule): the service-class approach.

The practice expense component of the Medicare fee schedule (MFS), which is currently based on historical charges and rewards physician procedures at the expense of cognitive services, is due to be changed by January 1, 1998. The Physician Payment Review Commission (PPRC) and others have proposed microcosting direct costs and allocating all indirect costs on a common basis, such as physician time or work plus direct costs. Without altering the treatment of direct costs, the service-class approach disaggregates indirect costs into six practice function costs. The practice function costs are then allocated to classes of services using cost-accounting and statistical methods. This approach would make the practice expense component more resource-based than other proposed alternatives.

Cost Allocation↗
PubMed1995

Functional outcome in patients after excision of extracanalicular acoustic neuromas using the suboccipital approach.

An audit of surgery for acoustic neuroma was carried out to determine the frequency and nature of postoperative symptoms and their impact upon the patient's quality of life and vocation. Fifty-six patients were interviewed between 6 months and 5 years (mean 26 months) after surgical excision of an acoustic neuroma. The objective surgical results in these patients are good, with normal or near normal functional preservation rates of 80% for the facial nerve (House-Brackmann grade I/II), and 27.3% for a previously functioning acoustic nerve. Despite this there was no significant overall reduction in the reported occurrence of balance problems, tinnitus, headache and other neurological sequelae of the tumour after surgical excision. In 20% of the patients persistent symptoms, including deafness and facial weakness, had prevented the resumption of former social activities. As a result of these symptoms 8.6% of the patients were certified medically unfit for work, but of those employed preoperatively over 70% had returned to their jobs. The success of neuro-otological surgical management of acoustic neuroma is offset by some degree of chronic morbidity. Our patients expressed the need to know whether their symptoms would resolve, but were often too afraid to ask. Patients can be reassured that the majority resume their former social and vocational activities, but should be advised that some symptoms can persist or occur de novo after surgery. Our data suggest that early intervention would reduce the incidence of these troublesome sequelae.

Adult↗
PubMed1994

Near-infrared spectroscopy in adults: effects of extracranial ischaemia and intracranial hypoxia on estimation of cerebral oxygenation.

We have studied the effects of extracranial ischaemia and intracranial hypoxia on measurement of cerebral oxygenation using near-infrared, reflectance-mode, cerebral oximetry (Invos 3100 cerebral oximeter) in healthy adult subjects. Under stable systemic conditions, scalp ischaemia induced by a pneumatic tourniquet caused an apparent reduction in mean regional cerebral oxygenation (rSO2) from mean 72 (SD 6)% to 59 (7)% (n = 8, P < 0.001). rSO2 returned to control values within 1 min of release of the tourniquet. Local scalp ischaemia induced by rapid frontalis muscle exercise caused a significant reduction (4.5 (2)% in rSO2 (n = 12, P < 0.001). The effect of systemic hypoxia on rSO2 was examined during controlled scalp ischaemia. A decrease in mean SpO2 from 98 (2)% to 66 (6)% was associated with a decrease in mean rSO2 from 57 (4)% to 41 (6)%. There was a significant correlation between the percentage reduction in rSO2 and SpO2 during hypoxia (r = 0.81, P < 0.001). We conclude that the Invos cerebral oximeter was capable of detecting tissue hypoxia deep to the scalp under carefully controlled conditions but that it also was affected significantly by changes in extracranial blood flow and oxygenation which may affect its reliability in clinical practice. Further work is necessary to define those situations in which cerebral oximetric monitoring is useful and valid.

Adult↗