From limbo to legitimacy: a theoretical model of the transition to the primary care nurse practitioner role

The initial transitional year of professional practice is thought to provide the critical foundation on which new professionals build their expertise. The purpose of this study was to describe the experiences of new nurse practitioner graduates during their first year of primary care practice. Thirty-five persons were interviewed alone or in focus groups at approximately 1, 6, and 12 months after graduation. Grounded theory methodology guided the data collection and analysis. A theoretical model was constructed that represents the transition to the primary care nurse practitioner role. This model consists of a process called From Limbo to Legitimacy, which encompasses four major categories: Laying the Foundation, Launching, Meeting the Challenge, and Broadening the Perspective. Each category contains a set of subcategories that detail the multiple aspects of the experience. This model highlights both the distress and the accomplishments of the initial year of advanced practice.

Ankylosing spondylitis in West Africans--evidence for a non-HLA-B27 protective effect

OBJECTIVE

To determine the prevalence of ankylosing spondylitis in the Fula ethnic group in The Gambia, and relate the disease prevalence to the B27 frequency and subtype distribution of that population.

METHODS

215 first degree relatives of 48 B27 positive Fula twin pairs, and 900 adult Fula males were screened for ankylosing spondylitis by clinical and, where appropriate, radiographic means. The B27 prevalence was determined by PCR/sequence specific oligonucleotides on finger prick samples from 100 unrelated Fula, and B27 subtype distribution by SSCP on unrelated B27 positive individuals. This data were then compared with the prevalence of ankylosing spondylitis among B27 positive Caucasians.

RESULTS

No case of ankylosing spondylitis was seen. Six per cent of Fula are B27 positive, of which 32% are B*2703 and 68% B*2705. Assuming the penetrance of ankylosing spondylitis in B27 positive Fula is the same as in B27 positive Caucasians, the probability of not observing any cases of ankylosing spondylitis among the Fula examined is remote (P = 6.7 x 10(-6)). Similarly, the chance of not seeing any cases among those expected to be either B*2705 or B*2703 was small (P = 3.2 x 10(-4) for B*2705, and P = 0.02 for B*2703).

CONCLUSIONS

The risk of developing ankylosing spondylitis in B27 positive Fula is lower than in B27 positive Caucasians. This is not explained by the B27 subtype distribution among Fula, and suggests the presence of some non-B27 protective factor reducing the prevalence of ankylosing spondylitis in this population.

Hypertension in pregnancy: maternal and fetal outcomes according to laboratory and clinical features

OBJECTIVES

To determine the predictive value of clinical and laboratory parameters for maternal and fetal complications in pregnant women with hypertension.

DESIGN

Prospective data collection.

SETTING

Two primary referral hospitals in the southern suburbs of Sydney between March 1987 and July 1994.

SUBJECTS

1183 pregnant women with hypertension managed conjointly by a physician and obstetrician.

INTERVENTION

Uniform management protocol, plus antihypertensive medications if systolic blood pressure was persistently > or = 160 mmHg and/or diastolic blood pressure > or = 90 mmHg.

MAIN OUTCOME MEASURES

Maternal and fetal complications, as defined by the Australasian Society for the Study of Hypertension in Pregnancy Consensus Statement.

RESULTS

Of 825 women with pre-eclampsia (502 mild; 323 severe), univariate analysis showed that hyperuricaemia, proteinuria and severe hypertension were significantly associated with a higher rate of maternal and fetal complications. In multivariate analyses without confounders, only primiparity, low serum albumin levels and absence of diabetes were significantly associated with severe pre-eclampsia. Severe pre-eclampsia, high haemoglobin levels and low platelet count were associated with higher rates of small-for-gestational-age babies, but only low serum albumin levels were associated with increased perinatal mortality rates. Low birthweight was associated with severe hypertension and severe pre-eclampsia.

CONCLUSIONS

Simple clinical and laboratory parameters are useful predictors for maternal and fetal outcomes in pregnancies complicated by hypertension.

Ambulatory blood pressure monitoring (ABPM) in the normal menstrual cycle and in women using oral contraceptives. Comparison with conventional blood pressure measurement

This study was undertaken to determine if blood pressures (BP) assessed by routine sphygmomanometry and 24 h ambulatory monitoring (ABPM) alter throughout the normal menstrual cycle or in the cycle of women using oral contraceptive pills (OCP), and the interrelationships between urinary sodium (Na) and potassium (K) excretion and ABPM throughout the menstrual cycle. Eleven women with a normal ovulatory cycle (ovulatory) and ten age-matched women taking an oral contraceptive pill (OCP) were studied three times in random order during their menstrual cycle, within days 1 to 5, 13 to 16, and 25 to 28. Twenty-four hour urine Na, K, and creatinine (Cr) excretion and serum Na, K, Cr, cortisol, estradiol, progesterone and plasma renin, angiotensinogen, and aldosterone concentrations were measured. BP was measured by a mercury sphygmomanometer and by 24 h BP (Accutracker II). On days 1 to 5, daytime systolic BP was higher in OCP [mean: 123 mm Hg, 95% confidence interval: 117, 128] than ovulatory women [114 mm Hg (109, 118); P = .011] though daytime diastolic BPs were similar [OCP: 71 (68, 75), ovulatory: 69 (66, 72)]. This difference in daytime systolic BP between groups was also apparent at both of the other stages of the menstrual cycle. Nighttime systolic BPs were significantly higher in OCP users on days 13 to 16 (P < .05) and days 25 to 28 (P < .01). In women taking OCPs, daytime ABPM for days 1 to 5 were higher than their office readings by 15 (7,23)/11 (7,15) mm Hg (P = .001), whereas office and ABPM readings were similar in ovulatory women. This pattern was evident at all three stages. There was no significant change in BP throughout the menstrual cycle within either group, and no correlation between urine Na or K and BP. Systolic BPs are higher throughout the menstrual cycle in women who take OCPs than in ovulatory women but this difference is only detected when ambulatory blood pressure is assessed. Blood pressure does not change subsequently in either ovulatory or OCP-taking women throughout the menstrual cycle.

Milk production in Angus, Brahman, and reciprocal-cross cows grazing common bermuda grass or endophyte-infected tall fescue

Milk yield and quality were measured on 139 Angus, Brahman, and reciprocal-cross cows grazing common bermuda grass or endophyte-infected tall fescue for 4 yr to evaluate interactions of direct and maternal breed effects and heterosis for these traits with forage environment. Milk yield was estimated by method of milking machine, and milk fat, protein, and somatic cell counts were evaluated in a commercial dairy laboratory. Monthly estimates were made beginning on an average d 61 of lactation and continued monthly for six estimates in 3 yr and five estimates in 1 yr. Data were averaged over month within year, and the model included sire breed, sire in sire breed, dam breed, forage, and age averages. Somatic cell counts were transformed using natural logarithms prior to analyses. Forage effects for milk yield were dissimilar among sire breed x dam breed subclasses (P < .10), resulting in higher levels of heterosis on common bermuda grass than on tall fescue. Maternal breed effects for milk yield favored Angus on bermuda grass (P < .05) but not on tall fescue, whereas direct breed effects were similar on both forages and favored Brahman. Milk fat was reduced on tall fescue compared to bermuda grass by an average of .6% (P < .01), and direct breed effects were similar across forages and averaged 1.04% (P < .01) in favor of Brahman. Heterosis and maternal breed effects for milk fat were not important. There was little evidence of direct and maternal breed effects or heterosis for milk protein or somatic cell counts. These data suggest that heterosis for milk yield is larger on common bermuda grass than on tall fescue and that grazing endophyte-infected tall fescue is detrimental to milk fat.

Primary hyperaldosteronism: a missed diagnosis in 'essential hypertensives'?

BACKGROUND

It has been recognised recently that primary hyperaldosteronism may be more common than previously thought, the frequency of diagnosis being improved by screening using a plasma aldosterone concentration to renin activity ratio.

AIMS

To determine the frequency of primary hyperaldosteronism, screening with both plasma aldosterone to renin concentration (PRC) and activity (PRA) ratios, in normokalaemic subjects previously diagnosed as having essential hypertension.

METHODS

Plasma potassium, aldosterone and PRCs and PRA and blood pressure (BP) were measured in 74 hypertensive subjects previously diagnosed by one physician as having essential hypertension. A normal range for plasma aldosterone/renin ratios was determined in 147 control subjects. Hypertensive subjects with elevated aldosterone/renin ratios were further assessed for primary hyperaldosteronism using saline loading and fludrocortisone suppression. Those in whom plasma aldosterone concentration exceeded 140 pmol/L after suppression tests underwent adrenal vein sampling for measurement of aldosterone and cortisol concentrations as well as adrenal CT scanning to diagnose the cause of primary hyperaldosteronism. The main outcome measures were a diagnosis of aldosterone producing adenoma or bilateral adrenal hyperplasia based upon adrenal vein sampling.

RESULTS

Four subjects (5%) had an elevated plasma aldosterone to renin ratio using PRC and six (8%) using PRA. Two subjects (2.7%) in this selected population had primary hyperaldosteronism, both of whom had BP > 160/110 mmHg at the time of testing.

CONCLUSIONS

The frequency of normokalaemic primary hyperaldosteronism appears to be greater than previously thought, though the true incidence in the general population of hypertensive subjects remains unknown. The sensitivity of diagnosis (but not specificity) may be improved by measurement of the plasma aldosterone/renin ratio and PRC is at least as adequate as PRA for this process.

HASTE MR imaging: description of technique and preliminary results in the abdomen

HASTE (Half fourier Single-shot Turbo spin-Echo) is a single-section T2-weighted sequence that acquires images in less than 1 second. Images are breathing independent and possess a variety of other features useful for imaging the abdomen. The design of this technique is described. Clinical studies of 38 consecutive patients were performed using this technique. HASTE images were considered good in 28 and fair in 10 patients, including five patients who could not suspend respiration. Definition of liver and bowel was particularly clear.

The 5' end of the BRCA1 gene lies within a duplicated region of human chromosome 17q21

To begin to address the hypothesis that abnormal regulation of the breast/ovarian cancer susceptibility gene BRCA1 is a critical step in sporadic breast/ovarian tumorigenesis, we have determined the detailed structure of the BRCA1 genomic region. We show that this region of the genome contains a tandem duplication of approximately 30 kilobases, which results in two copies of BRCA1 exons 1 and 2, of exons 1 and 3 of the adjacent 1A1-3B gene and of the previously reported 295 base pair intergenic region. Sequence analysis of the duplicated exons of BRCA1 and 1A1-3B and flanking genomic DNA reveals maintenance of the intron-exon structure and a high degree of nucleotide sequence identity, suggesting that these are non-processed pseudogenes and that the duplication is a recent event in evolutionary terms. We also show that a processed pseudogene of the acidic ribosomal phosphoprotein P1 (ARPP1) is inserted directly upstream of pseudo-BRCA1 exon 1A. We believe that these findings could not only confound BRCA1 mutation analysis, but could have implications for the normal and abnormal regulation of BRCA1 transcription, translation and function.

Infections in HIV-infected patients with malignancy

With the increasing prevalence of HIV, better combination treatment regimens, and preventive therapy for opportunistic infections, physicians will be caring for an ever-increasing number of survivors with an ever-dwindling immune function. Increasing this burden is the unfortunate patient who also develops cancer concurrent with HIV infection. The combined risk factors of these diseases make a worst-case scenario in evaluation and treatment of infections. This article reviews AIDS-defining tumors and other malignancies, risk factors for infection, opportunistic infections, and therapy strategies.

Abnormal IL-4 gene expression by atopic dermatitis T lymphocytes is reflected in altered nuclear protein interactions with IL-4 transcriptional regulatory element

Among the atopic disease, atopic dermatitis is characterized by the highest levels of serum IgE and by increased peripheral blood T-cell interleukin-4 (IL-4) production. IL-4 promotes IgE synthesis by B cells and stimulates the growth of IL-4-producing T cells and may contribute to the pathogenesis of this disease. In this study, in situ hybridization established that atopic dermatitis patients have a higher frequency of IL-4-producing peripheral blood T cell when compared to normal subjects. These in vivo-derived T cells were used to examine the signaling requirements of IL-4 production and the nuclear factors that associate with a critical IL-4 transcriptional regulatory element between -88 and -60 relative to the IL-4 transcription initiation site, the activation responsive element. We demonstrate that, as in T-cell lines, proteins belonging to the NF-AT and AP-1 family of transcription factors are present in stimulated cell extracts and specifically associate with the activation responsive element. Dysregulated IL-4 production is reflected in the nuclear proteins that associated this element. Using gel shift assays, we found that 12 of 12 nuclear extracts from stimulated atopic T cells formed the activation-dependent protein-DNA complex, compared to only 2 of 12 normal T-cell extracts. Activation complex formation correlated with the relative level of IL-4 mRNA and protein produced in stimulated T cells, suggesting that abnormal IL-4 gene expression in atopic disease may be linked to alterations in nuclear protein interactions with these promoter elements.

HLA class I associations of ankylosing spondylitis in the white population in the United Kingdom

OBJECTIVE

To investigate the HLA class I associations of ankylosing spondylitis (AS) in the white population, with particular reference to HLA-B27 subtypes.

METHODS

HLA-B27 and -B60 typing was performed in 284 white patients with AS. Allele frequencies of HLA-B27 and HLA-B60 from 5926 white bone marrow donors were used for comparison. HLA-B27 subtyping was performed by single strand conformation polymorphism (SSCP) in all HLA-B27 positive AS patients, and 154 HLA-B27 positive ethnically matched blood donors.

RESULTS

The strong association of HLA-B27 and AS was confirmed (odds ratio (OR) 171, 95% confidence interval (CI) 135 to 218; p < 10(-99)). The association of HLA-B60 with AS was confirmed in HLA-B27 positive cases (OR 3.6, 95% CI 2.1 to 6.3; p < 5 x 10(-5)), and a similar association was demonstrated in HLA-B27 negative AS (OR 3.5, 95% CI 1.1 to 11.4; p < 0.05). No significant difference was observed in the frequencies of HLA-B27 allelic subtypes in patients and controls (HLA-B*2702, three of 172 patients v five of 154 controls; HLA-B*2705, 169 of 172 patients v 147 of 154 controls; HLA-B*2708, none of 172 patients v two of 154 controls), and no novel HLA-B27 alleles were detected.

CONCLUSION

HLA-B27 and -B60 are associated with susceptibility to AS, but differences in HLA-B27 subtype do not affect susceptibility to AS in this white population.

The effects of selection for size in cattle on horn fly population density

Statistically significant differences were observed in the population density of the horn fly, Haematobia irritans irritans L., on Angus cows having significantly different frame sizes. Angus cows, averaging < 112.5 cm in height at the hip, had significantly lower numbers of horn flies than Angus cows that measured 112.5-117.5 cm, 117.5-120 cm, 120-126 cm and > 126 cm in height at the hip. The Angus I cows ( < 112.5 cm in height at the hip) were significantly shorter in length (mean distance from the withers to the hip bone) and were smaller in girth than the Angus II (112.5-126 cm) and Booneville Angus cows ( > 126 cm). The estimated heritability (h2) of horn fly resistance was 0.43 +/- 0.07 and 0.95 +/- 0.31 for 1989 and 1990, respectively. Horn fly counts on the Angus I herd ( < 112.5 cm in height) was 118.1 (probable breeding value, PBV = -20.69) to 165 horn flies per cow (PBV = 26.9 flies per cow in 1989) and from 75.9 (PBV = -29.1) to 134.5 (PBV = 29.5) flies per cow in 1990. Angus I bulls had PBV = -23.7 to 13.4 and from -26.5 to 14.75 in 1989 and 1990, respectively. The Angus II cows had horn fly counts that ranged from 159.6 (PBV of -23.5) to 208.1 (PBV of 25) per cow in 1989 and from 232.3 (PBV of -56.2) to 378.7 (PBV of 90) per cow in 1990. Angus II bulls had PBVs that ranged from -17.1 to 18.9 in 1989 and from -28.1 to 48.8 in 1990. The Angus I cows had significantly (P < 0.0001) lower numbers of horn flies (mean of 63.8 horn flies per m2) than the small, medium or large Angus II cows (mean of 129.4, 149.6 and 145.5 horn flies per m2, respectively). The data indicated that some specific factor(s) associated with cow size contribute(s) to innate resistance of cattle to the horn fly.

Identification and partial characterization of alpha 2-macroglobulin from the tuatara (Sphenodon punctatus)

alpha 2-Macroglobulin (alpha 2-M), a large molecular mass proteinase-binding protein, was identified in plasma from tuatara (Sphenodon), a rare reptile endemic to New Zealand. In this genus, alpha 2-M constitutes 11-13% of total plasma protein (approximately 2.2-3.9 mg/mL). Analysis of blood samples collected at approximately monthly intervals from individual tuatara indicated that the plasma level of alpha 2-M remains fairly constant. The subunits of tuatara alpha 2-M have an apparent molecular mass of approximately 160 kDa as determined by SDS-polyacrylamide gel electrophoresis and the intact protein is an oligomer that contains inter-chain disulfide bonds. N-terminal sequence analyses of tuatara alpha 2-M revealed a distinct similarity to alpha-macroglobulins of other vertebrates and that at least two types of alpha 2-M subunits are present in plasma of tuatara.

A liver-lung connection

A 35-year-old man presented with cough, expectoration of green sputum, and right-sided pleuritic chest pain. Symptoms had begun the previous day and he had vomited the night before. The patient also complained of chronic fatigue, a 12-lb. weight loss, insomnia, right-sided back pain, and lower extremity myalgias. He denied having had fever, chills, diaphoresis, dyspnea, diarrhea, dysuria, abdominal pain, skin lesions, or jaundice.

A case of pneumonia with extrapulmonary manifestations

A 24-year-old man presented with a nonproductive cough, fever, and occasional shaking chills of one week's duration. he also had pleuritic left-sided chest pain on deep inspiration and a rash on his palms, soles, trunk, and mouth. His wife had been sick with "pleurisy" two weeks earlier; her symptoms had resolved with antibiotic therapy.

Preeclampsia: the effects of serum on endothelial cell prostacyclin, endothelin, and cell membrane integrity

OBJECTIVE

Our purpose was to determine whether serum from women with preeclampsia or gestational hypertension (1) decreased endothelial cell prostacyclin, (2) increased endothelial cell endothelin, and (3) caused endothelial cell damage.

STUDY DESIGN

Production of 6-keto-prostaglandin F1 alpha and endothelin by cultured endothelial cells was measured after 48 hours' incubation with sera from 23 nonpregnant women, 23 normal pregnant women, 12 women with preeclampsia, and 11 women with gestational hypertension. Structure damage of endothelial cells was assessed by a chromium release assay.

RESULTS

Serum from normal pregnant women induced more endothelial prostacyclin but less endothelin than did serum form nonpregnant women (p<0.05). No difference was found between normal pregnant and hypertensive pregnant women for prostacyclin production, but serum of preeclamptic women induced less endothelin production than did that of normal pregnant women (p<0.05). Chromium 51 release by endothelial cells was similar between normal pregnant and hypertensive pregnant groups.

CONCLUSIONS

Serum from preeclamptic women stimulates less endothelin production than does serum from normal pregnant women but does not alter prostacyclin production and is not cytotoxic to endothelial cells after short-term incubation.

Nuclear factor of activated T cells is associated with a mast cell interleukin 4 transcription complex

Interleukin 4 (IL-4), an immunoregulatory cytokine, is produced only by a subset of activated T cells and cells of the mast cell-basophil lineage. The production of IL-4 by mast cells likely represents a significant source of this protein in local immune-inflammatory responses in the skin, brain, gastrointestinal, and respiratory tracts, in which mast cells are prevalent. In the present study, the cis- and trans-acting elements that control inducible mast cell IL-4 gene transcription were examined and compared with those that function in T cells. We demonstrate that, as in T cells, sequences between bp -87 and -70 are critical for protein association and activation-dependent gene transcription and that this region (termed the activation-responsive element region) is the target of an inducible, cyclosporin A-sensitive, DNA-protein interaction. When assessed by electrophoretic mobility shift assays and UV cross-linking analyses, multiple proteins in both T- and mast cell nuclear extracts associate with the activation-responsive element in vitro, and some of these appear identical. However, distinct proteins are associated with each of the complexes as well. AP-1 family members are unique to the T-cell-stimulation-dependent complex, whereas mast cell complexes contain factors that are reactive with anti-nuclear factor of activated T cells p (NF-ATp) and anti-NF-ATc antibodies but have distinct molecular masses compared with those of T-cell-derived NF-AT. Furthermore, an anti-NF-ATp-reactive factor with a molecular mass of approximately 41 kDa is present in the nuclei of unstimulated cells and binds independently of cell activation, unlike the previously described NF-AT family members. These data support the idea that there are uniquely regulated, cell lineage-specific transcription factors related to T-cell-derived NF-AT that mediate inducible IL-4 transcription in mast cells. These differences likely reflect the distinct cell surface signaling requirements for IL-4 production in T and mast cells.

Distinct transcription start sites generate two forms of BRCA1 mRNA

Using primer extension and 5' RACE, we have mapped the 5' end of the BRCA1 gene and identified a new 5' exon. Two distinct BRCA1 transcripts differing by the first exons were found; these transcripts were generated by the alternative use of dual promoters and alternative splicing. The expression of the distinct transcripts was examined in four primary tissues (placenta, mammary gland, testis and thymus), six normal or cancer cell lines, four primary breast tumor tissues and four primary ovary tumour tissues. Both transcripts were detected in all the samples studied, with the exon 1a transcript being the major expressed form in mammary gland and the exon 1b transcript in placenta. This suggests that the two transcripts may be expressed in a tissue-specific fashion. The 5' flanking regions of both BRCA1 transcripts were analysed, neither contains a TATA box. Initiator elements, which have been proposed to mediate transcription in TATA-less promoters, were found at the transcription initiation sites. Transcription factor binding sites such as Sp1, PEA3, C/EBP, CREB, E4F1 and Pu boxes were identified in the 5' flanking regions of the exon 1a transcript, and Sp1, NF-kB and PEA3 binding sites in the 5' flanking region of the exon 1b transcript. The interactions of these DNA elements with trans-acting factors are likely to modulate the alternative use of the distinct transcription start sites and the expression of the BRCA1 gene.

The physiology of pre-eclampsia

1. Pre-eclampsia is a multisystem disorder of human pregnancy with a genetic predisposition. It occurs more commonly in first pregnancies and primarily affects maternal renal, cerebral, hepatic and clotting functions while elevating blood pressure. The foetus is affected through placental insufficiency arising from abnormal 'placentation', that is, failure to adequate trophoblast invasion of maternal vasculature, and possible from abnormal autacoid production. 2. Pre-eclampsia is caused by the placenta; delivery of the placenta is the only known cure. Its manifestations are considered secondary to organ hypoperfusion which arises as a result of vasoconstriction, intravascular coagulation and reduced maternal blood volume. 3. Current hypotheses propose that pre-eclampsia is due to widespread maternal endothelial cell damage, perhaps secondary to a cytotoxic factor released by the placenta. This hypothesis has gained wide acceptance, but scientific evidence is lacking. 4. Defining the abnormal balance of vasoactive factors in pre-eclampsia has proved a difficult task. There is enhanced pressor activity to infused angiotensin II (AII) despite reduced plasma concentrations of AII, renin and aldosterone. Prostacyclin production appears reduced, and the balance of thromboxane/prostacyclin favours vasoconstriction and platelet aggregation. There is no convincing evidence for enhanced endothelin or reduced nitric oxide production. Plasma concentrations of atrial natriuretic peptide are paradoxically elevated in the face of plasma volume contraction. An intriguing observation, which remains unexplained, is why some vascular beds are affected predominantly in one patient (eg. hepatic ischaemia) while another has a similar degree of hypertension but involvement of a different organ system (eg. renal insufficiency yet normal liver function). 5. Volume homeostasis is disturbed with redistribution of intravascular volume to the interstitial fluid space due to increased capillary permeability and in some cases reduced plasma oncotic pressure. This redistribution is not always clinically apparent as peripheral oedema. Whether this change in volume is compensated for by venoconstriction and maintenance of adequate cardiac output is undetermined. 6. Improved understanding of the pathophysiology of pre-eclampsia is necessary to allow better clinical management of this serious disorder.

Inadequacy of dipstick proteinuria in hypertensive pregnancy

The objective of this study was to determine the accuracy of ward urinalysis and the sensitivity of dipstick testing in the assessment of proteinuria in hypertensive pregnant women. Subjects were 230 consecutive hypertensive pregnant women who were admitted to hospital over a 2-year period. Routine ward urinalyses for protein, obtained on a mid-stream sample before and after a 24-hour urine collection for quantitating proteinuria, were compared with the 24-hour urine protein excretion. As a control for dipstick accuracy, urinalysis was also performed on a mixed aliquot of each of the 24-hour samples by a single observer experienced in urinalysis. True proteinuria was considered as > 300 mg/day. The positive predictive value for urinalysis ranged from 38% (for the precollection test) to 60% (for tests on the aliquot). Negative predictive values were 86-88%. The false negative rates at 'nil' or 'trace' proteinuria ranged from 8-18%. The false positive rates at '3+' (3 g/L) or '4+' (> or = 20 g/L) ranged from 0-17%, at '2+' (1 g/L) from 18-50% and at '1+' (0.3 g/L) from 67-83%. Best results for urinalysis were obtained on the aliquot testing but even under these ideal circumstances there was a high false positive rate (67%) at '1+' (0.3 g/L) urinalysis level. These studies show that in routine clinical practice 'nil' or 'trace' proteinuria will miss significant proteinuria in approximately 1 out of 8 hypertensive pregnant women while '3+' (3 g/L) or '4+' ( > or = 20 g/L) will rarely be a false positive. At urinalysis of '1+' or '2+' a 24-hour urine collection is required to be certain about the presence or absence of proteinuria. Research studies should demand 24-hour urine protein quantitation and not rely solely upon urinalysis results.

Acute renal failure following cardiac surgery: incidence, outcomes and risk factors

BACKGROUND

Acute renal failure (ARF) is a recognised complication following cardiac surgery, but the incidence varies widely in the published literature and there are no Australian data available to help predict the risks of ARF in patients with pre-existing renal disease.

AIM

To determine the incidence, outcome and risk factors for ARF following cardiac surgery.

METHODS

A retrospective case control analysis of 903 consecutive patients who had cardiac surgery (795 CABG, 68 valve/septal surgery, 40 combined valve/CABG) in 1992-93. ARF was defined as doubling of serum creatinine concentration (Cr) to > 0.13 mmol/L if serum Cr was < or = 0.13 mmol/L pre-operatively, or else a rise in serum Cr of > or = 0.10 mmol/L after cardiac surgery. For each subject with ARF, two case control subjects were matched for date of surgery, surgeon, age, sex, type of surgery and pre-operative serum Cr to permit analysis of the influence of pre-operative factors (hypertension, diabetes mellitus, left ventricular systolic dysfunction) and for the comparison of cardiopulmonary bypass time upon the development of ARF. Subsidiary endpoints were mortality, need for dialysis and length of hospital stay.

RESULTS

ARF developed in only 1.1% of patients with 'normal' pre-operative renal function (creatinine < or = 0.13 mmol/L) and none required dialysis. ARF developed in 16% of those with impaired pre-operative renal function, 20% of whom required dialysis. Mortality from ARF was 13%. The risk of ARF rose from 10.4% in those with pre-operative serum Cr 0.14-0.20 mmol/L to 36.8% if the serum Cr was > 0.20 mmol/L (p < 0.01). Mortality was higher (4.2% vs 0.7%, p < 0.01) and length of hospital stay longer (14.5 vs nine days [median], p < 0.001) in those with impaired pre-operative renal function. ARF was more likely in those over 65 years, if valve surgery was included and where there was prolonged cardiopulmonary bypass time.

CONCLUSIONS

These data confirm that ARF following cardiac surgery is uncommon without pre-operative impairment of renal function but currently carries a mortality rate of 13%. Impaired renal function alone is associated with higher mortality and prolonged hospital stay. Studies to prevent ARF in this setting should focus on the high risk subsets described in this study.