Nasal continuous positive airway pressure reduces sleep-induced blood pressure increments in preeclampsia

Preeclampsia is the predominant cause of admissions to neonatal intensive care. The diurnal blood pressure pattern is flattened or reversed in preeclampsia. We hypothesized that snoring and partial upper airway obstruction contribute to nocturnal rises in blood pressure. We tested this hypothesis by controlling sleep- induced upper airway flow limitation and snoring with nasal positive pressure. Eleven women with preeclampsia underwent two consecutive polygraphic sleep studies with simultaneous beat-to-beat blood pressure monitoring. Average blood pressure for the night overall and in each sleep stage was calculated. Sleep architecture was similar on the two study nights. Sleep-induced partial upper airway flow limitation occurred in all patients in the initial study. Autosetting nasal continuous positive airway pressure (CPAP) applied at a mean maximal pressure of 6 +/- 1 cm H(2)O eliminated flow limitation throughout sleep on the treatment night. Blood pressure was markedly reduced on the treatment night [(128 +/- 3)/(73 +/- 3)] when compared with the initial nontreatment study night [(146 +/- 6)/(92 +/- 4)], p = (0.007)/(0.002). We conclude that partial upper airway obstruction during sleep in women with preeclampsia is associated with increments in blood pressure, which can be eliminated with the use of nasal CPAP.

A tale of two systems: the changing academic health center

Major changes in academic health centers (AHCs) may not be confined to the United States. Both Partners HealthCare System in Boston and University College London School of Medicine/University College Hospital Trust in London have recently undergone mergers, downsizing, and cost cutting on unprecedented scales. A comparison of the recent histories of these eminent AHCs reveals striking similarities in the clinical and academic pressures bearing down upon them and in their responses. It also reveals important differences in their situations and actions, traceable in large part to the contrasting roles of governments and markets in the health care economies of these two countries.

Age-related brain volume reductions in amphetamine and cocaine addicts and normal controls: implications for addiction research

The study evaluated the relationship between age and frontal and temporal lobe volumes in young cohorts of cocaine-dependent (CD), amphetamine-dependent (Am), and normal control subjects. Ten CD, nine Am, and 16 age- and gender-matched control subjects underwent magnetic resonance imaging (MRI). The volume of the frontal and temporal lobes was measured from an identically positioned slab of seven contiguous 3-mm-thick coronal images. Follow-up measures of the gray and white matter subcomponents of these volumes were also obtained. Both CD and Am groups had a significantly smaller temporal lobe volumes, but only the CD group demonstrated a significantly greater decline in temporal lobe volume with age (intracranial volume, education, and race were controlled for in all statistical analyses). Segmenting the brain regions into gray and white matter revealed that the negative correlation between age and temporal lobe volume of CD patients was mostly due to a significant age-related decline in the gray matter subcomponent. Negative trends between age and gray matter volumes were also observed in the Am and normal groups. In the frontal lobes, age was negatively correlated with gray matter volume in the control, CD, and Am groups. Unlike the consistent decreases in gray matter volumes, white matter showed non-significant increases in volume with age. The data suggest that CD patients may have an accelerated age-related decline in temporal lobe gray matter volume and a smaller temporal lobe volume compared to normal controls. In the frontal lobe, age-related gray matter volume reductions occur in all three groups. These age-related cortical gray matter volume reductions may be a biological marker for the risk of addictive behavior, which also decreases with age.

Primary care trusts. Barrier grief

Primary care trusts that want to shift resources from hospitals will face many of the barriers that have frustrated others before them. Part of the difficulty lies in hospitals' fixed overhead costs, which cannot be saved if patients are transferred. Incentives in the system tend towards preserving the status quo. PCTs will have to make full use of the relationship between GPs and consultants to effect change.

Home care case management. Perspectives from the home front

Focus groups were held with home care case managers in two cities in Canada which provided information on the role of the case manager, factors that influence decision making, recent changes that have taken place in case management, and the different and positive aspects of home care case management. Factors which influence decision making were grouped into organizational, client, family, other professionals, and case management factors. The differences in case managers' preparation and functions in the two sites are discussed. The difficult aspects of case management included making tough decisions related to client resources, and client, work life, and management issues. The positive aspects included the personal interaction with clients, the opportunity to follow through on services to clients, the diversity of case management work, and the opportunity for relatively independent professional practice.

Prevention of rejection in cardiac transplantation by blockade of the interleukin-2 receptor with a monoclonal antibody

BACKGROUND

Alloantigen-activated T cells express the high-affinity interleukin-2 receptor. Specific blockade of this receptor with the human IgG1 monoclonal antibody daclizumab may prevent rejection of allografts after cardiac transplantation without inducing global immunosuppression.

METHODS

We randomly assigned 55 nonsensitized patients undergoing a first cardiac transplantation to receive either induction therapy with daclizumab (1.0 mg per kilogram of body weight), given intravenously within 24 hours after cardiac-transplantation surgery and every two weeks thereafter, for a total of five doses, or generalized immunosuppressive therapy. Concomitant immunosuppression was achieved in both groups with cyclosporine, mycophenolate mofetil, and prednisone. The primary end points were the incidence and severity of acute rejection, and the length of time to a first episode of biopsy-confirmed rejection.

RESULTS

Of the 55 patients in the study, 28 were randomly assigned to receive daclizumab and 27 served as the control group. During induction therapy, the mean frequency of acute rejection episodes (defined as a histologic grade of 2 or higher according to the classification of the International Society of Heart and Lung Transplants) was 0.64 per patient in the control group and 0.19 per patient in the daclizumab group (P=0.02). Acute rejection developed in 17 of 27 patients in the control group (63 percent), as compared with 5 of 28 patients in the daclizumab group (18 percent; relative risk, 2.8; 95 percent confidence interval, 1.1 to 7.4; P=0.04). Throughout follow-up, there were nine patients with episodes of acute rejection of histologic grade 3 in the control group, as compared with two in the daclizumab group (P= 0.03), and the time to a first episode of rejection was significantly longer in the daclizumab group (P=0.04). There were no adverse reactions to daclizumab and no significant differences between the groups in the incidence of infection or cancer during follow-up.

CONCLUSIONS

Induction therapy with daclizumab safely reduces the frequency and severity of cardiac-allograft rejection during the induction period.

International collaborative workshops. A 6-year partnership between Canada and China

Interprofessional exchanges such as workshops are common activities in international development programs. The authors describe processes used to select, implement, and evaluate six collaborative workshops held in Tianjin, China, between 1990 and 1995. These workshops targeted curricular change for a baccalaureate nursing program in Tianjin Medical University. Our experience highlights the importance of understanding the assumptive base for change, developing an institutional memory in both partner universities, introducing interactive teaching methods congruent with Chinese value systems, and using a formative evaluation strategy to foster cross-cultural dialogue and mutual understanding among project partners.

Intravenous immunoglobulin reduces anti-HLA alloreactivity and shortens waiting time to cardiac transplantation in highly sensitized left ventricular assist device recipients

BACKGROUND

Recipients of left ventricular assist devices (LVADs) develop prominent B-cell hyperreactivity. We investigated the influence of anti-HLA antibodies on waiting time to cardiac transplantation in LVAD recipients and compared the effects of 2 immunomodulatory regimens on anti-HLA serum reactivity.

METHODS AND RESULTS

Fifty-five previously nonsensitized LVAD recipients of a TCI device implanted between 1990 and 1996 were studied. Patients with anti-HLA antibodies received monthly courses of either intravenous immunoglobulin (IVIg) or plasmapheresis, in conjunction with cyclophosphamide. The effects of these regimens on anti-HLA alloreactivity and waiting time to transplantation were then determined by Kaplan-Meier log-rank statistics, nonparametric Wilcoxon rank-sum test, and Student's t test. Prolongation in transplant waiting time was related to serum IgG anti-HLA class I alloreactivity. Infusion of IVIg (2 g/kg) caused a mean reduction of 33% in anti-HLA class I alloreactivity within 1 week. Waiting time to transplantation was significantly reduced by IVIg therapy and subsequently approximated that in nonsensitized patients. Side effects of IVIg (2 g/kg) were minimal and related primarily to immune complex disease. Although plasmapheresis caused a similar reduction in alloreactivity to IVIg, this effect was achieved after longer treatment. Moreover, plasmapheresis was associated with an unacceptably high frequency of infectious complications. In patients resistant to low-dose (2 g/kg) IVIg therapy, high-dose (3 g/kg) IVIg was effective in reducing alloreactivity but was associated with a high incidence of reversible renal insufficiency.

CONCLUSIONS

These results indicate that IVIg is an effective and safe modality for sensitized recipients awaiting cardiac transplantation, reducing serum anti-HLA alloreactivity and shortening the duration to transplantation. The therapeutic and safety profile of IVIg would appear to be superior to plasmapheresis.

Surgical management of the patient with an implanted cardiac device: implications of electromagnetic interference

OBJECTIVE

To identify the sources of electromagnetic interference (EMI) that may alter the performance of implanted cardiac devices and develop strategies to minimize their effects on patient hemodynamic status.

SUMMARY BACKGROUND DATA

Since the development of the sensing demand pacemaker, EMI in the clinical setting has concerned physicians treating patients with such devices. Implanted cardiovertor defibrillators (ICDs) and ventricular assist devices (VADs) can also be affected by EMI.

METHODS

All known sources of interference to pacemakers, ICDs, and VADs were evaluated and preventative strategies were devised.

RESULTS

All devices should be thoroughly evaluated before and after surgery to make sure that its function has not been permanently damaged or changed. If electrocautery is to be used, pacemakers should be placed in a triggered or asynchronous mode; ICDs should have arrhythmia detection suspended before surgery. If defibrillation is to be used, the current flow between the paddles should be kept as far away from and perpendicular to the lead system as possible. Both pacemakers and ICDs should be properly shielded if magnetic resonance imaging, positron emission tomography, or radiation therapy is to be used. The effect of EMI on VADs depends on the model. Magnetic resonance imaging adversely affects all VADs except the Abiomed VAD, and therefore its use should be avoided in this population of patients.

CONCLUSIONS

The patient with an implanted cardiac device can safely undergo surgery as long as certain precautions are taken.

The incidence of T2-weighted MR imaging signal abnormalities in the brain of cocaine-dependent patients is age-related and region-specific

BACKGROUND AND PURPOSE

Cocaine and its metabolites can produce vasospasm, and cocaine-dependent patients are at increased risk for stroke. Based on previous case reports, we hypothesized that the incidence of hyperintense brain lesions observed on T2-weighted MR images would also be increased in asymptomatic cocaine-dependent individuals.

METHODS

Sixty-two male "crack" (smoked) cocaine-dependent participants ranging in age from 25 to 66 years were compared with 116 normal male control participants ranging in age from 25 to 80 years. Those with histories of neurologic symptoms or illnesses were excluded. The severity of hyperintense lesions was rated on a 0- to 3-point scale, and ratings of 3 were used in the data analysis as an indicator of a probable pathologic process. Three regions were separately rated: the cerebral white matter, insular subcortex white matter, and subcortical gray matter (basal ganglia and thalamus region).

RESULTS

Significantly increased risk of severe lesions was observed in the two white matter regions of the cocaine-dependent group (odds ratio of 16.7 and 20.3) but not in the subcortial gray matter region (odds ratio of 1.4). In the insula subcortex white matter, the risk of lesions increased with age in the cocaine-dependant sample, but remained essentially absent among normal controls through the age of 80 years. In the cerebral white matter, the relationship of age and risk of lesion among normal participants was similar in shape to that in cocaine-dependent participants, but equivalent risk was seen 20 years earlier among cocaine-dependent participants.

CONCLUSIONS

Cocaine-dependent participants had a significantly increased age-related risk of white matter damage. The possible clinical implications of this damage are discussed.

Development and evaluation of the cane use cognitive mediator instrument

BACKGROUND

Canes are among the most underutilized assistive devices for older persons. A significant obstacle to understanding cane use behaviors of older adults is the lack of instruments measuring factors that may influence seniors' decisions to accept or reject these devices.

OBJECTIVES

Guided by the Theory of Planned Behavior, this study involved the development and evaluation of an instrument to measure cognitive determinants of cane use among community-living older adults.

METHOD

The two-phase design involved: a) instrument formation including item generation from four focus group interviews with seniors (n = 30), expert panel evaluation (n = 10), and pilot testing (n = 10); and b) instrument validation in a cross sectional survey (n = 106).

RESULTS

Psychometric analyses of survey data provided empirical evidence of the construct validity and reliability of the instrument. Principal components analysis verified the hypothesized four-factor solution, explaining 63.2% of variance. Independent t-tests yielded statistically significant differences (p < 0.001) in mean scores between the two contrasting groups of cane users (n = 51) and nonusers (n = 55) with respect to each of the four factors identified. Alpha coefficients of 0.81 to 0.96 indicated high internal consistency of the instrument.

CONCLUSIONS

The instrument can be used by clinicians and researchers to assess seniors' salient beliefs about the consequences of cane use, guide tailored intervention strategies to promote acceptance and effective use, and evaluate the effectiveness of interventions.

Changes in Canadian women's mammography rates since the implementation of mass screening programs

OBJECTIVES

This study reports on Canadian mammography rates between 1990, when mass screening programs were launched, and 1994/95.

METHODS

Mammography rates from 2 national surveys were compared according to the presence of a provincial screening program.

RESULTS

Mammography rates among women aged 50 to 69 years (the targeted group) increased significantly, by 16%; increases were twice as high in provinces with screening programs. Among women in their 40s (nontargeted group), the changes were insignificant and independent of screening program status.

CONCLUSIONS

Screening programs appear to have influenced the mammography rates of targeted women aged 50 to 69 years.

Haemodynamic responses to obstructive sleep apnoeas in premenopausal women

OBJECTIVES

Obstructive apnoeas during sleep are associated with marked cyclical blood pressure fluctuations in men with obstructive sleep apnoea (OSA). Haemodynamic responses to OSA in women are largely unknown. We aimed to investigate haemodynamics during apnoeic events in women with OSA and to assess the influence of the menstrual cycle on these responses.

DESIGN AND METHODS

Full overnight polysomnography and continuous non-invasive blood pressure monitoring was performed in 13 women with OSA during follicular and luteal phases of the menstrual cycle. Change in blood pressure (deltaBP) from pre- to post-apnoea termination was measured for each apnoeic cycle.

RESULTS

Only 10 of 13 subjects ovulated. In women who ovulated, pressor responses to apnoea termination occurred in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, but substantially increased during the luteal phase of ovulatory cycles [NREM change in mean arterial pressure (deltaMAP) 12 +/- 3 mmHg during the follicular phase and 20 +/- 3 mmHg during the luteal phase, P < 0.001; REM deltaMAP 11 +/- 3 mmHg during the follicular phase and 23 +/- 3 mmHg during the luteal phase, P < 0.001]. Sleep apnoea severity did not change during the cycle in NREM sleep, but was reduced in REM during the luteal phase. Changes in pressor responses were absent in non-ovulating subjects.

CONCLUSIONS

Obstructive apnoeas in women were associated with marked blood pressure changes, similar to those previously reported in men. While respiratory events improved slightly in the luteal phase, blood pressure responses to these events increased by approximately 100%. Thus, the menstrual cycle has discordant effects on the respiratory and cardiovascular effects of OSA in women.

Building community health nursing in the People's Republic of China: a partnership between schools of nursing in Ottawa, Canada, and Tianjin, China

Community health nursing in China is an emerging specialty. A multi-component collaborative endeavor between the Schools of Nursing of Tianjin Medical University, China, and the University of Ottawa, Canada is described. This project, funded by the Canadian International Development Agency, commenced in 1989. It has laid the groundwork for an expanded role for community health nurses in Tianjin, a municipality of 11 million people located in Northeast China. The historical context for the evolution of community health nursing in China and the emergence of community health nursing as a priority area within the project are described. Major project activities are highlighted, illustrating several underlying principles for strengthening the educational preparation of baccalaureate nurses who can apply community health skills. These include creating a critical mass of faculty who can teach community health nursing, modelling classroom and clinical teaching of community health nursing, bridging the gap between nursing in the community and nursing, in the hospital, and developing a prototype for baccalaureate community health nursing experience. Lessons learned from this initiative are summarized.

Smoking in pregnancy and postpartum: relationship to mothers' choices concerning infant nutrition

The objective of this study was to examine the relationship between maternal smoking status and infant nutrition. Women delivering in 5 hospitals in the Ottawa-Carleton region of Ontario were screened for eligibility over a 6-month period in 1993. Follow-up data were collected by telephone at 3 months postpartum using a validated questionnaire. Mothers were retrospectively asked about their infant-feeding choices and their smoking behaviours. Logistic regression analyses were used to determine the significance of demographic factors and maternal smoking behaviours in relationship to 3 feeding practices: bottlefeeding at birth, discontinued breastfeeding by 12 weeks, and introduction of solids by 12 weeks. A total of 796 women participated in the longitudinal study (90% follow-up rate). Less-educated; younger; single, separated or divorced; and foreign-born mothers were more likely to bottlefeed at birth. Less-educated women more often discontinued breastfeeding before 12 weeks. Mothers who had smoked during part or all of their pregnancy and were smoking at the time of the interview were significantly more likely than non-smokers to bottlefeed at birth or to discontinue breastfeeding by 12 weeks. Current smokers were also more likely than non-smokers to have introduced solid food by 12 weeks. Maternal smoking was a significant predictor of infant nutrition, with other sociodemographic factors taken into account. Smoking status should be included in clinical screening tools for infant nutrition. The relationship between other dimensions of maternal smoking (e.g., timing of quitting attempts, degree of partner support, partner's smoking behaviours) and infant-feeding practices warrants investigation.

Emergency admissions. Over the threshold

Analysis of emergency admissions to six hospitals over three weeks in winter found marked differences in the severity of cases. Some admissions could have been avoided if more investigations had been available on an outpatient basis. Where community services are easily accessible and available seven days a week, those admitted to hospital are likely to be more severely ill. British guidelines are needed on medical admissions.