Multi-wavelength spectrophotometric analysis for detection of xanthochromia in cerebrospinal fluid and accuracy for the diagnosis of subarachnoid hemorrhage

BACKGROUND

Cerebrospinal fluid (CSF) was examined for bilirubin, an important indicator for diagnosis of subarachnoid hemorrhage (SAH).

METHODS

A multi-wavelength (340, 415, and 460 nm) spectrophotometric assay was developed for the quantitative measurement of bilirubin in CSF, enabling the mathematical correction for absorbance of hemoglobin and proteins. Bilirubin and hemoglobin results were correlated to HPLC and a standard colorimetric assay, respectively. A subset of samples was sent for an absorbance reading at 450 nm following baseline correction. The multi-wavelength bilirubin assay was validated on 70 patients with confirmed SAH and 70 patients with neurologic symptoms who ruled out for SAH.

RESULTS

The multi-wavelength spectrophometric assay demonstrated no interferences due to proteins (albumin) up to 30 g/l or oxyhemoglobin up to 260 mg/l. The assay limit of detection was 0.2 mg/l, linear to 20 mg/l, and CVs ranged from 1 to 6% at bilirubin concentrations of 0.84 and 2.1mg/l. The spectrophotometric assay correlated to HPLC and the colorimetric assay for bilirubin and hemoglobin, respectively. Results also correlated to the absorbance method (with removal of samples with high hemoglobin and proteins). The area under the ROC curve for diagnosis of SAH was 0.971 and 0.954 for the HPLC and spectrophotometric assay, respectively. At a cutoff of 0.2mg/l, the clinical specificity was 100% for both assays, and the clinical sensitivity was 94.3% and 88.6% for SAH for the HPLC and spectrophotometric asays, respectively.

CONCLUSIONS

The multi-wavelength spectrophotometric assay is an objective alternative to visual inspection, HPLC, and absorbance for CSF bilirubin.

Interpersonal processes of care in diverse populations

Persons of lower socioeconomic status and members of racial and ethnic minority groups experience poorer health and increased health risk factors. A framework of interpersonal processes of care specifies distinct components and incorporates the perspective of diverse racial and ethnic or socioeconomic groups. Its dimensions, each with several domains, are communication (general clarity, elicitation of and responsiveness to patient concerns, explanations, empowerment), decision making (responsiveness to patient preferences, consideration of ability and desire to comply), and interpersonal style (friendliness, respectfulness, discrimination, cultural sensitivity, support). All the domains, except cultural sensitivity, were validated through a survey of 603 ethnically diverse, low-income adults. Confirmation of the framework's usefulness should enable researchers to explore how interpersonal processes might account for observed ethnic and social class differences in health care and health.

Increasing incidence of withholding and withdrawal of life support from the critically ill

To determine whether limits to life-sustaining care are becoming more common, we attempted to quantify the incidence of recommendations to withhold or withdraw life support from critically ill patients, to describe how patients respond to these recommendations, and to examine how conflicts over these recommendations are resolved. In 1992 and 1993 we prospectively enrolled 179 consecutive patients from two intensive care units (ICUs) for whom a recommendation was made to withhold or withdraw life support. Where possible, we compared results with data collected in the same units over a similar time period in 1987 and 1988. Recommendations to withhold or withdraw life support preceded 179 of 200 deaths (90%) in 1992 and 1993, compared with 114 of 224 deaths (51%) in 1987 and 1988 (chi2 = 73.76, p < 0.001]. Cardiopulmonary resuscitation was initiated in 10% of deaths in 1992 and 1993 as compared with 49% in 1987 and 1988. Ninety percent of patients agreed within less than 5 d, and only eight patients (4%) refused physicians' recommendations to limit life support. In cases of conflict, physicians in 1992 and 1993 deferred to patients with one exception: physicians were willing to refuse surrogate requests for resuscitation of patients they considered hopelessly ill. We conclude that 90% of patients who die in these ICUs now do so following a decision to limit therapy, that this represents a major change in practice in these institutions over a period of 5 yr, that most patients and surrogates accept an appropriate recommendation to withhold or withdraw life support, and that physicians will refuse surrogate requests in certain circumstances.

Physician responses to a hospital policy allowing them to not offer cardiopulmonary resuscitation

OBJECTIVE

To determine whether physicians followed a hospital policy permitting them to not offer cardiopulmonary resuscitation (CPR) to patients considered unlikely to benefit from this therapy.

DESIGN

Prospective series.

SETTING

San Francisco General Hospital, a university-affiliated public hospital.

PATIENTS

Attending physicians were interviewed about patients admitted over a period of 5 consecutive months for whom do-not resuscitate (DNR) orders were written. Only the first patient for whom each physician wrote a DNR order was included.

MAIN OUTCOME MEASURES

Responses of physicians to questions regarding their initiation of DNR orders for these patients.

RESULTS

Sixty-nine physicians responded to questions about DNR orders written for 69 patients. Fifty-seven of these physicians said that they were aware of the hospital policy, and 49 of the 57 physicians said that they generally agreed with it. Thirty-three physicians felt that CPR should be offered only to patients likely to benefit from it. In contrast, 36 physicians said that CPR should be offered to all patients, regardless of benefit. CPR was offered to 41 patients and 15 surrogates; 27 of these patients were considered to be unlikely to benefit from CPR.

CONCLUSION

Despite a policy that allows them to do otherwise, physicians usually offered CPR to patients, regardless of benefit. Most physicians believed that CPR should be offered to all patients. These findings suggest that policies such as that of San Francisco General Hospital may not be compelling because physicians hold attitudes that are inconsistent with the policies.

Determinants of decision making for circumcision

Research is ongoing concerning the medical risks and benefits of routine neonatal male circumcision. Interpretation of the data, however, is controversial. Circumcision presents a number of challenges in obtaining informed consent because of a variety of interesting issues. It is a nonemergent, elective procedure that allows for evaluation and discussion over time. In this respect, observation of the informed consent process for circumcision is relevant to other medical decisions, such as advance directives, discussed between primary care providers and patients. Obtaining informed consent for circumcision has its constraints. The process generally occurs over a brief hospital stay. There have been recent changes in the official position regarding the procedure by professional medical societies, and it raises considerable psychologic issues for the provider and may Impact the way in which Information is provided.

Withholding and withdrawing of life support from patients with severe head injury

OBJECTIVE

To characterize the withholding or withdrawing of life support from patients with severe head injury.

SETTING

San Francisco General Hospital, a city and county hospital with a Level I trauma center.

DESIGN

A standardized questionnaire was used to collect data on demographics and functional outcome of severely head-injured (Glasgow Coma Score of < or = 7) patients admitted to the medical-surgical intensive care unit, and to interview the patients' physician and family members.

PATIENTS

Forty-seven patients who were admitted to a medical-surgical intensive care unit over a 1-yr period.

INTERVENTIONS

Twenty-four patients had life support withheld or withdrawn, and 23 patients did not.

MEASUREMENTS AND MAIN RESULTS

Physician and family separately assessed patient's probable functional outcome, degree of communication between them, reasons important in recommending or deciding on discontinuation of life support, and the result of action taken. Six months later, the families reviewed the process of their decision, how well physician(s) had communicated, and what might have improved communication. Of 24 patients with life support discontinued, 22 died; two were discharged from the hospital. Twenty-three of the 24 patients had a poor prognosis on admission. Of the 23 patients who were continued on life support for the duration of their hospitalization, ten had a poor (p < .001) prognosis on admission. Prognosis improved for two patients from the first group and five from the latter. Family's assessment of prognosis agreed with physician's assessment in 22 of the 24 patients from whom life support was discontinued (p < .001). Physicians' ability to convey the prognosis appeared to influence families' assessments. Physicians' considerations in recommending limitation of care and families' considerations in making decisions were the same, primarily an inevitably poor prognosis. Neither physician nor families cited cost or availability of care as a deciding factor. Two families disagreed with the recommendation to limit care after initial agreement because the patients' prognosis improved from "likely death" to "vegetative." Care was therefore continued, and both patients remained vegetative 6 months after admission to the hospital and discharge to chronic care facilities.

CONCLUSIONS

Life support is commonly withheld or withdrawn from patients with severe head injury at San Francisco General Hospital, and usually it is accompanied by death. A reciprocal consideration exists in most cases between the physician and family making the difficult decision to limit care. Care is provided for patients whose families request it despite physician recommendations.

The ethical appropriateness of using prognostic scoring systems in clinical management

The four ethical principles of beneficence, nonmaleficence, autonomy, and social justice provide a framework for making medical decisions, including those that involve the administration of life-sustaining therapies. In recent years, a number of prognostic scoring systems, including the Acute Physiology Assessment and Chronic Health Evaluation (APACHE) system, have been developed to augment clinical judgment in determining which critically ill patients are likely to benefit from such therapies. Although these systems all have limitations, their use in decision making is as ethically appropriate as is the use of clinical judgment, which has its own limitations and has been used for years.

Postnatal human immunodeficiency virus antibody testing. The effects of current policy on infant care and maternal informed consent

Routine human immunodeficiency virus (HIV) antibody screening of umbilical cord blood identifies neonates at risk for HIV infection but may hold risks as well as benefits for infants and mothers. We describe the effect of testing on infant placement and care and report the women's understanding of pretest counseling and consent. In a case-control analysis of 327 tested infants, seropositive infants (13) had a higher rate of discharge to home (62%) than did controls (31%). More case infants (100%) received follow-up care and vaccinations than control infants (46%). Of 32 women interviewed after HIV antibody test informed consent, only 31% understood that a positive cord blood test result was inconclusive for the infant, and most (78%) did not identify any associated socioeconomic risks. Most (88%) stated an interest in learning their serostatus, but only 22% returned for test results. Despite the benefits of HIV antibody testing of at-risk infants, current testing and counseling procedures inadequately inform women, limiting the testing benefits to them.

Ordering and administration of sedatives and analgesics during the withholding and withdrawal of life support from critically ill patients

OBJECTIVE

To determine why and how sedatives and analgesics are ordered and administered during the withholding and withdrawal of life support from critically ill patients.

DESIGN

Prospective case series.

SETTING

Medical-surgical intensive care units at a county hospital and a university hospital.

PATIENTS

Consecutive 1-year sample of 22 patients from whom life support was withheld or withdrawn in one intensive care unit at a county hospital and a random sample of 22 similar patients in the intensive care unit in the university hospital over the same period.

MAIN OUTCOME MEASURES

Physicians and nurses were interviewed to determine their reasons for ordering and administering drugs, and medical records were reviewed to document amounts of drugs ordered and administered.

RESULTS

Drugs were given to 75% of patients during withholding and withdrawal of life support. Patients who did not receive medication were comatose and considered incapable of benefiting from sedation and analgesia. The median time until death following the initiation of the withholding or withdrawal of life support was 3.5 hours in the patients who received drugs and 1.3 hours in those patients who did not (P, not significant). Physicians ordered drugs to decrease pain in 88% of patients, to decrease anxiety in 85%, to decrease air hunger in 76%, to comfort families in 82%, and to hasten death in 39%; in no instance was hastening death the only reason cited. The amounts of benzodiazepines and opiates averaged 2.2 mg/h of diazepam and 3.3 mg/h of morphine sulfate in the 24 hours before withholding and withdrawal of life support and 9.8 mg/h and 11.2 mg/h in the 24 hours thereafter (P less than .025 and P less than .001, respectively).

CONCLUSIONS

Large doses of sedatives and analgesics were ordered primarily to relieve pain and suffering during the withholding and withdrawal of life support, and death was not hastened by drug administration.

Critical care of patients with AIDS

OBJECTIVE

We sought to review the clinical and ethical issues surrounding critical care for patients with the acquired immunodeficiency syndrome (AIDS).

DATA SOURCES

We reviewed published studies and abstracts dealing with the outcome of critical care for patients with AIDS, decision making about life-sustaining treatments in patients with AIDS, and infection control in the intensive care unit. We also consulted with a number of experts in the field.

STUDY SELECTION

We selected outcome studies in which patients with documented AIDS or infection with the human immunodeficiency virus (HIV) were analyzed. We rejected data concerning patients with suspected or presumed AIDS and data concerning presumed cases of Pneumocystis carinii pneumonia (PCP).

DATA SYNTHESIS

Most AIDS patients who require critical care do so because of respiratory failure caused by PCP. Although studies early in the epidemic reported survival rates to hospital discharge of 0% to 14%, recent studies demonstrate improved survival rates of 36% to 55%. Treatment for patients with PCP and respiratory failure should include either intravenous trimethoprim-sulfa-methoxazole or pentamidine isethionate, as well as adjuvant corticosteroids. Patients with AIDS may require critical care for many other indications, including seizures, sepsis, and hypotension, or reasons unrelated to their immunodeficiency. In general, such patients have a better prognosis than those with respiratory failure.

CONCLUSION

The provision of critical care for PCP and respiratory failure specifically or AIDS generally cannot be considered futile. Therefore, decisions about the use of critical care should be guided by the particular clinical situation and the patient's preferences. More research is needed to elucidate the reasons for the improving survival for patients with PCP and respiratory failure and the predictors of such survival.

Physician risk and responsibility in the HIV epidemic

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Homer A. Boushey, MD, Professor of Medicine, under the direction of Lloyd H. Smith, Jr, MD, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143.

Doctors divided: AIDS and the physicians at San Francisco General

Images

Telling patients the diagnosis is cancer: a teaching module

Twenty first-year residents and senior medical students participated in a brief teaching module in which they told a simulated patient she had a cancer diagnosis. A feedback session with selected videotape review identified individuals' strengths and weaknesses. Most showed high levels of concern for the patient and honesty, although almost half gave excessive amounts of data and scientific explanations. The exercise was extremely well received by the physicians in training.

Determination of brain death

With the careful application of the principles outlined herein, brain death can be determined with certainty. There have been no documented reports of survivors when these guidelines have been followed. The traid of a known mechanism of brain injury, absence of contributing metabolic or toxic central nervous system depression and absence of demonstrable brain function is sufficient to determine brain death clinically and, in most states, legally. The use of apneic oxygenation protects cadaver organs for transplantation during the period needed to prove that a patient cannot breathe. Very little can ameliorate the tragedy of sudden and unexpected fatal cerebral injury. Nonetheless, the concept of brain death is well established, and there is no longer a medical or an ethical reason to prolong unnecessary support of these patients.