[Determination of hearing thresholds in children using auditory brainstem responses : Influence of sedation and anaesthesia on quality and measurement time]. / Hörschwellenbestimmungen bei Kindern mittels früher akustisch evozierter Potenziale : Einfluss von Sedierung und Narkose auf Qualität und Messzeit.

BACKGROUND: A fundamental prerequisite for successful application of auditory brainstem responses (ABR) in paedaudiological diagnostics is to ensure a high quality of the measurement. This is commonly quantified by means of the residual noise. Key factors are the averaging number and the magnitude of spontaneous electroencephalogram (EEG). This is the first study to quantify the influence of different forms of sedation (anaesthesia, sedation with chloral hydrate or melatonin, natural sleep) on the individual EEG magnitude in children. MATERIALS AND METHODS: ABR measurements of 80 children aged between 1 month and 6 years were analysed retrospectively. Individual mean EEG amplitude was calculated from the averaging number and the residual noise. The results were analysed statistically with the type of sedation as a factor. From the mean EEG amplitudes, a theoretical recording time for a residual noise level of 35 nV was estimated. RESULTS: The spontaneous EEG activity is, on average, 2.5-times larger in awake children than in naturally sleeping children and more than 4­times larger than in sedated children. Although the EEG amplitude in intubation anaesthesia was smaller than with the other three types of sedation, this difference was not significant. The theoretical measurement time for 35 nV of residual noise was 10-times larger in awake than in sedated children. CONCLUSION: The large difference in spontaneous EEG activity between awake and sedated children indicates that sedation should be used for estimation of hearing thresholds on the basis of ABR. Only in rare cases is a reliable estimate of hearing thresholds likely to be obtained from ABR in awake children. Since different types of sedation do not influence the measurement time significantly, selection can be made solely on the basis of age and medical indication.

The use of nurse practitioners in the acute care setting.

A collaborative practice model was initiated in a university hospital to assist resident physicians to coordinate patient care on specialty services. Nurse practitioner (NP) data were collected on daily work activities and categorized as direct care, indirect care, administration, education, and research. Satisfaction surveys were collected from patients, physicians and nursing staff. Data on clinic evaluation and management service provided by the NPs were reported. The study supported the appropriateness of NPs in the acute care setting.

Vascular nurse practitioner: a collaborative practice role in the acute care setting.

A collaborative practice model was initiated in a 440-bed university teaching hospital to trial the appropriateness and effectiveness of placing a nurse practitioner (NP) in the acute-care setting with a group of vascular surgeons. The vascular NP and three physicians collaborated as providers of patient care in both ambulatory and hospital settings. The NP managed and coordinated patient care. After orientation, the NP used a data-tracking form to record daily work activities categorized as direct care, indirect care, administration, education, and research. Satisfaction surveys were distributed to patients, nurses, and physicians to measure key elements of the NP's job responsibilities as they related to each group. The NP's data were independently analyzed, implications were discussed, and results were collated for presentation. The data were also used to guide future practice. The data reflected the vascular NP's unique acute care role within a specialty service.

Short- and long-term effects of spirapril on renal hemodynamics in patients with essential hypertension.

Sixteen essential hypertensive patients were entered into a protocol assessing the effect of Spirapril, an angiotensin-converting enzyme (ACE) inhibitor, on blood pressure, the renin-aldosterone system, and renal function. Specifically monitored before, during 6 weeks, and 6 months of Spirapril therapy were plasma renin activity, plasma aldosterone, serum ACE, the renal clearances of creatinine, inulin, and para-aminohippurate, and urinary albumin excretion. Blood pressure was well controlled. Spirapril stimulated plasma renin activity and suppressed ACE throughout the entire protocol. Renal clearances were unchanged. Renal vascular resistance was decreased. Urinary albumin excretion was decreased. The authors conclude that the ACE inhibitor, Spirapril, when used as an effective antihypertensive agent, preserves renal function, lowers renal vascular resistance, and decreases urinary albumin excretion.

A randomized, double-blind, placebo-controlled trial to evaluate the effect of enalapril in patients with clinical diabetic nephropathy.

It is unknown if the antiproteinuric effect of angiotensin-converting enzyme (ACE) inhibitors reflects attenuation in the rate of progression of diabetic nephropathy. We report the results of a randomized, double-blind clinical trial designed to evaluate the longitudinal (18-month) effect of the ACE inhibitor, enalapril (5 to 40 mg/d), versus a placebo on 24-hour urinary protein excretion and on the rate of progression of renal disease in 33 patients with clinical diabetic nephropathy. Systemic blood pressure was controlled throughout the trial with conventional antihypertensive drugs. Glomerular filtration rate (GFR), determined by Tc99mDTPA renal clearance, and urinary protein excretion were monitored at 3-month intervals. Enalapril, in contrast to placebo therapy, was associated with an initial (40%) and sustained (33%) decrease in urinary protein excretion. Patients randomized to both enalapril or placebo experienced mean decreases in GFR, from 1.01 mL/s/1.73 m2 (61 mL/min/1.73 m2) to 0.85 mL/s/1.73 m2 (51 mL/min/1.73 m2), and from 1.06 mL/s/1.73 m2 (64 mL/min/1.73 m2) to 0.97 mL/s/1.73 m2 (58 mL/min/1.73 m2), respectively. Eleven of 18 patients (61%) randomized to enalapril, and 10 of 15 (66%) patients randomized to placebo, had a decrease in GFR; their rates of progression were -1.18 mL/min/1.73 m2/mo and -1.00 mL/min/1.73 m2/mo, respectively. In the absence of changes in blood pressure, the addition of an ACE inhibitor to patients with clinical diabetic nephropathy could not be shown to confer a unique renal protective effect. A prolonged decrease in 24-hour protein excretion could not be shown to predict attenuation in the progression of established clinical diabetic nephropathy.

Aneroid sphygmomanometers. An assessment of accuracy at a university hospital and clinics.

Defects of aneroid sphygmomanometers are a source of error in blood pressure measurement. We inspected 230 aneroid sphygmomanometers for physical defects and compared their accuracy against a standard mercury manometer at five different pressure points. An aneroid sphygmomanometer was defined as intolerant if it deviated from the mercury manometer by greater than +/- 3 mm Hg at two or more of the test points. The three most common physical defects were indicator needles not pointing to the "zero box," cracked face plates, and defective tubing. Eighty (34.8 of the 230 aneroid sphygmomanometers were determined to be intolerant with the greatest frequency of deviation seen at pressure levels of 150 mm Hg or greater. We recommend that aneroid manometers be inspected for physical defects and calibrated for accuracy against a standard mercury manometer at 6-month intervals to prevent inaccurate blood pressure measurements.

The effect of nifedipine GITS on renal function in hypertensive patients with renal insufficiency.

Twelve hypertensive patients with moderately severe renal dysfunction were entered into a protocol to assess the blood pressure and renal effects of the sustained release calcium antagonist, nifedipine GITS (30-180 mg/d given once a day) administered for 5 weeks. Nifedipine GITS monotherapy effectively lowered blood pressure in 50% of the patients. Glomerular filtration rate and effective renal plasma flow were increased 18% and 20%, respectively. The filtration fraction and urinary protein excretion remained unchanged. Changes that were observed in renal function were independent of the blood pressure responses of the patients; there was no correlation between the systemic and renal effect of nifedipine GITS monotherapy. Patients who had a poor systemic blood pressure response exhibited an increase in glomerular filtration rate (+11%) but had a decrease in effective renal plasma flow (-6%); patients who achieved a goal blood pressure response showed increases in both glomerular filtration rate (+35%) and effective renal plasma flow (+40%). These results show that nifedipine GITS monotherapy has the potential to improve renal function abnormalities that are encountered in hypertensive patients with renal disease; the improvement in renal function may be independent of their effect on systemic blood pressure.