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Biomedical subjects

R Koch

Publications and source records attributed to R Koch.

At least 109 records · Page 6Linked to original sources
PubMed1999

Factors influencing shunt dependency after aneurysmal subarachnoid haemorrhage.

In this retrospective analysis of 138 patients treated for ruptured aneurysms the development of shunt dependent hydrocephalus was evaluated regarding possible predictive factors. In 15 patients (11%) ventriculo-atrial shunt was implanted due to hydrocephalus. One predictive factor was the localisation of aneurysms as patients with hydrocephalus had PcoA aneurysms in 40% compared to 20% in the group of patients without hydrocephalus and only 7% compared to 28% MCA aneurysms. An other predictive factor was the severity of the subarachnoid haemorrhage (SAH) as 7 patients out of the 15 were graded Fisher IV on admission. Furthermore, an important predictive factor was the presence of acute hydrocephalus as 13 out of the 15 patients (87%) with shunt dependent hydrocephalus had acute hydrocephalus requiring external ventricular drainage. An other possible factor was the intraoperative opening of the lamina terminalis as in 73% of the patients with shunt dependent hydrocephalus compared to 82% in the group of patients without hydrocephalus this procedure was performed during surgery. The results suggest that shunt dependency is more likely after severe SAH especially in the presence of an acute hydrocephalus and in patients with aneurysms located in the basal cisterns. Therefore treatment of the acute hydrocephalus and possible the opening of the lamina terminalis could have a positive effect on the development of shunt dependent hydrocephalus after SAH.

Adolescent↗
PubMed1998

Quantitative evaluation of global and regional left ventricular diastolic function with color kinesis.

BACKGROUND: Diastolic wall motion asynchrony is a major determinant of impaired left ventricular (LV) filling in patients with concentric hypertrophy and coronary artery disease. We evaluated the ability of Color Kinesis, a new echocardiographic technique that color-encodes endocardial motion, to quantitatively assess global and regional LV filling properties. METHODS AND RESULTS: Color Kinesis images and mitral and pulmonary vein flow Doppler data were acquired in 29 patients with LV hypertrophy and 29 age-matched control subjects. In addition, Color Kinesis data were correlated to coronary angiographic findings in 15 patients with suspected coronary artery disease. Segmental analysis of Color Kinesis images was used to obtain time histograms of regional diastolic fractional area change, wherein early and late peaks (peaks 1 and 2) reflected rapid LV filling and atrial contraction, respectively. Regional mean LV filling time and filling curves were used to objectively identify diastolic endocardial motion asynchrony in patients with LV hypertrophy and coronary artery disease. None of the mitral and pulmonary vein Doppler indices differentiated patients with normalized mitral Doppler profile (n=13) from control subjects, whereas reduced peak1/peak2 ratio and prolonged mean filling time indicated augmented contribution of atrial contraction toward LV filling (P<.05). In 22 of 25 patients with LV hypertrophy and preserved systolic function and in all patients with coronary artery disease, delayed diastolic endocardial motion was observed in at least one segment. CONCLUSIONS: Analysis of Color Kinesis images provides objective assessment of global and regional LV filling properties and allows identification of both diastolic dysfunction in patients with normalized Doppler indices and wall motion asynchrony.

Adult↗
PubMed1998

Rapid and prognostically valid quantification of immunohistochemical reactions by immunohistometry of the most positive tumour focus. A prospective follow-up study on breast cancer using antibodies against MIB-1, PCNA, ER, and PR.

The prognostic significance of immunohistochemical markers for cell proliferation [MIB-1, proliferating cell nuclear antigen (PCNA)] and hormone receptor analysis [oestrogen receptor (ER), progesterone receptor (PR)] was tested by means of immunohistometry in a series of 103 breast cancer patients in comparison with the lymph node status N, the tumour size T, histomorphological grading, and the biochemical ER and PR status. Immunohistochemical reactions were performed on 2 microns sections from paraffin-embedded tissue, using an indirect peroxidase method. The proportion of immunostained tumour cell nuclei was determined using a TV-image analysis system. Measurements were performed using a 20 x objective on 40 viewing fields (1.94 mm2, MIB-1 and PCNA) or 20 viewing fields (0.97 mm2, ER and PR). The mean immunopositivity of all viewing fields and the value of the most immunopositive viewing field (MIB-1max, PCNAmax, PRmax, ERmax) were calculated. The mean values and the maximal values were highly correlated (r = 0.903, P < 0.001). After 1:2:1 quantilization, 84.2 per cent of the 412 single measurements revealed mean and maximal values in the same category (P < 0.0001). For each of the four immunohistochemical markers, the prognostic significance of the maximal values was higher than that of the mean values. The highest prognostic significance was found for MIC-1max (P = 0.0002), followed by PRmax (P = 0.0046), ERmax (P = 0.0154), and PCNAmax (P = 0.0161). From the results of a Cox model, a 'prognostic index (PI)' was developed, ranging from -1 to 8: PI = 2 x N + T + MIB-1max-PRmax. The four groups of patients with PI values of < 2, 2-3, 4-5, and > 5 revealed significantly different 7.5-year survival probabilities (P < 0.0001). The simplicity of the PI makes it a clinically useful, routinely applicable, and understandable parameter in the surgical pathology of breast carcinoma.

Adult↗
PubMed1998

Different distribution of HLA class II and tumor necrosis factor alleles (TNF-308.2, TNFa2 microsatellite) in anti-topoisomerase I responders among scleroderma patients with and without exposure to quartz/metal dust.

OBJECTIVE: To investigate the influence of quartz/ metal dust exposure on the pathogenesis of systemic sclerosis (SSc; scleroderma), by an immunogenetic comparison of HLA class II and tumor necrosis factor (TNF) alleles in patients with and without exposure. METHODS: A retrospective study of 30 SSc patients exposed to quartz/metal dust (qSSc) and 50 patients with idiopathic SSc (iSSc) was conducted by DNA-based typing of HLA, TNF-308, and TNFa/b microsatellite alleles. RESULTS: A neutral or protective haplotype in iSSc anti-topoisomerase I (anti-topo I) responders was found to be a susceptibility haplotype in qSSc patients. HLA-DRB1*0301 (DR3), a component of the extended haplotype HLA-DQA1*0501;B1*0201;DRB1*0301; TNF-308.2;TNFa2/b3, had a decreased frequency in iSSc anti-topo I responders compared with non-responders (P = 0.03, odds ratio [OR] 0.11, 95% confidence interval [95% CI] 0.00-0.95), but a significantly increased frequency in qSSc anti-topo I responders compared with controls and with iSSc anti-topo I responders (P = 0.00004, Pcorr = 0.006, OR 11.38, 95% CI 3.17-44.35 and P = 0.0002, Pcorr = 0.02, OR 30.0, 95% CI 2.05-986, respectively). In contrast, DRB1*1104 (DR5) and DRB1*11/15 (DR5/DR2) with no TNF-308.2 and TNFa2 alleles were prevalent in only the iSSc anti-topo I responders compared with controls (P = 0.0005, Pcorr = 0.04, OR 11.0; 95% CI 2.68-45.93 and P = 0.0002, Pcorr = 0.02, OR 12.43, 95% CI 3.65-40.04, respectively). CONCLUSION: The mechanisms that lead to the development of anti-topo I in qSSc and iSSc patients are suggested to be distinct, although it is not clear that the two diseases themselves are different.

Autoantibodies↗
PubMed1998

Mild hyperphenylalaninemia and heterozygosity of the phenylalanine hydroxylase gene.

Newborn screening for phenylketonuria (PKU) is now the standard of practice. Initial phenylalanine blood levels of 240 mumol/L result in referral of affected newborns to medical facilities experienced in caring for patients with metabolic disorders. This case report concerns a female infant born in 1976 with a presumptive positive PKU screening test on the third day of life of 240 mumol/L phenylalanine. Follow-up levels while the mother was breast feeding on the sixth day of life were 324 and, on the 27th day, 312 mumol/L. She was subsequently lost to follow-up at age 11 years, but returned at 19 years of age due to pregnancy, with a blood phenylalanine level of 132 mumol/L. Mutation studies then were performed documenting that she was a carrier for the phenylalanine hydroxylase gene and did not have hyperphenylalaninemia. The mother's parents and the infant were also genotyped confirming heterozygosity. The infant on follow-up is completely normal, following a normal pregnancy.

Adult↗
PubMed1998

Enhanced expression of selectins in human skin wounds.

The aim of the study was to characterize the vitality and age of skin wounds by the detection of selectins. A prospective study was conducted for this purpose in which 197 vital human skin wounds (time since injury ranging from 3 min to 790 days) were investigated immunohistologically. Of the samples tested, 97 were taken from autopsy material and 100 from patient material from the department of surgery at the university hospital. The selectins were detected in paraffin sections after autoclaving and using the ABC technique. The intensity was rated by a semi-quantitative evaluation using a four-stage ordinal scale. Strong positive immunohistochemical reactions were observed for the P-selectin 3 min at the earliest and 7 h at the latest after the time of injury. For the E-selectin a positive staining was evident I h at the earliest and 17 days at the latest from the time the skin was injured. The staining intensity decreased significantly after an interval of 12 h from the time of injury (P < 0.05). The L-selectin was regularly detected on leukocytes in the samples of injured skin. The immunohistochemical results for the P- and E-selectins were significantly different between injured and uninjured skin (P < 0.01). The expression of the selectins is indicative of the vitality of the wound. P-selectin was detected in a few cases (n=4) at low intensity while E-selectin could not be found in the control samples (n=31) of postmortem skin wounds. The use of P- and E-selectins for forensic purposes can help to achieve better estimates of the age of wounds with short survival times.

Female↗
PubMed1998

Effect of high dose verapamil on restenosis after peripheral angioplasty.

OBJECTIVES: We sought to determine whether treatment with high dose verapamil prevents restenosis in patients at high risk for reoccurrence after successful percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND: Restenosis is the major limitation of PTCA. Calcium antagonists have demonstrated some potential as inhibitors of this process. METHODS: A total of 98 patients with peripheral occlusive arterial disease (POAD), stable angina pectoris, mild hypertension and at least one additional risk factor increasing the likelihood of restenosis after angioplasty were selected for this placebo-controlled, double-blind, randomized trial. Verapamil (240 mg twice daily) or placebo was taken for 6 months. Efficacy variables assessed before and after angioplasty and at 6 weeks and 6 months after PTCA included thickness of the intima/media complex degree of stenosis, interventricular septal thickness, crurobrachial pressure ratios of dorsalis pedis and posterior tibial arteries, distance to claudication and total vessel diameter. RESULTS: No significant intergroup differences emerged before or immediately after PTCA. Six weeks after angioplasty, a significant thickening of the intima/media complex in the treated vascular segment of 14.3% occurred in the placebo group versus 0% among verapamil patients (p < 0.01). At 6 months, the intima/media thickness was 35.7% greater in the placebo group but had decreased by 14.3% in the verapamil group (p < 0.001). At 6 months, a marked reduction in septal thickness was observed in the verapamil group versus that in the placebo group (p < 0.001). The rate of restenosis was also significantly lower in the verapamil group (p < 0.001). Few minor side effects were reported. CONCLUSIONS: In patients with POAD at increased risk for restenosis, the administration of high dose verapamil prevented recurrent stenosis for 6 months after successful peripheral angioplasty and was well tolerated.

Aged↗
PubMed1998

Neonatal neurological assessment of offspring in maternal phenylketonuria.

This study assesses the impact of prenatal and postnatal factors in maternal phenylketonuria (PKU). The Dubowitz Neurological Assessment of the Preterm and Full-term Newborn Infant was administered within the first 8 days of life to 56 offspring of women with PKU and 45 controls. Follow-up testing of the maternal PKU offspring at age 1 year consisted of the Bayley Scales of Infant Development and the Receptive-Expressive Emergent Language Scale (REEL). In addition, the Home Observation for Measurement of the Environment (HOME Scale) was given. Birth weight was lower (z = 2.0, p = 0.045), birth length was lower (z = 2.1, p = 0.03) and birth head circumference was smaller (z = 3.5, p = 0.0005) in the maternal PKU offspring than in the control infants. Examiners rated 29% of the maternal PKU offspring and 9% of the control infants abnormal (Fisher's exact test, p = 0.01). At 1 year of age, 19% of the maternal PKU offspring attained a Bayley Developmental Quotient (DQ) and a score on the Bayley Motor Scale below 85; 19% had receptive language delay; and 26% had expressive language delay. The gestational age at which the mother attained metabolic control was an important factor associated with birth measurements, the Dubowitz Rating and subsequent developmental scores. The Dubowitz Neurological Assessment score did not predict developmental outcome (chi-square = 1.3, p = 0.53), while the HOME score correlated with the DQ (r = 0.36, p = 0.02). In logistic regression analyses, the home environment was a greater determinant of risk for a low DQ than whether or not the mother attained metabolic control prior to pregnancy (OR = 0.85, p = 0.02). These results suggest that treatment strategies addressing both prenatal and postnatal factors will most effectively reduce risks in maternal PKU.

Developmental Disabilities↗
PubMed1998

How to involve staff in developing an outcomes-oriented organization.

Outcomes management requires the active participation of clinical staff and/or network providers to succeed. They form the bedrock of the system, since they are the ones who most typically administer the outcomes assessment questionnaires to consumers, encourage them to complete them, and respond to questions and complaints about them. Resistance from clinicians can cause even the most well-designed outcomes management system to fail. Yet with the application of several basic principles, organizations can maximize active participation from its clinicians to operate a dynamic outcomes management system. The authors of this article describe the principles involved, and the action steps necessary to implement them. These principles include: articulate the value of the outcomes management system, involve clinical staff in its design, make it relevant to treatment goals, assure clinicians the system will not be used punitively, show them how it will be used to improve treatment, obtain staff feedback routinely on how the system is working, and demonstrate how the organizational culture from top management down uses the outcomes information to make decisions.

Attitude of Health Personnel↗
PubMed1997

Thyreoglobulin and violent asphyxia.

The concentration of thyreoglobulin (tg) was determined for death caused by hanging, strangulation by ligature, and throttling. Cases of sudden death (traumatic aortic rupture, penetrating wounds of the heart) were used for comparison. The mean values in cases of hanging (149.9 +/- 202.3 ng/ml), strangulation by ligature (193.1 +/- 173.3), manual strangulation (561.6 +/- 173.9) are distinguishable from violent acute deaths (23.3 +/- 27.6) and living healthy individuals (17.3 +/- 16.1). By means of statistical comparisons, significant differences were found between throttling and strangulation by ligature and between throttling and hanging (adjusted P < 0.001). In connection with examination of the bodies high tg values can be regarded as a vital reaction in obstructive asphyxia.

Asphyxia↗
PubMed1997

Segmental analysis of color kinesis images: new method for quantification of the magnitude and timing of endocardial motion during left ventricular systole and diastole.

BACKGROUND: We describe a method for objective assessment of left ventricular (LV) endocardial wall motion based on Color Kinesis, a new echocardiographic technique that color-encodes pixel transitions between blood and myocardial tissue. METHODS AND RESULTS: We developed a software that analyzes Color Kinesis images and provides quantitative indices of magnitude and timing of regional endocardial motion. Images obtained in 12 normal subjects were used to evaluate the variability in each index. Esmolol, dobutamine, and atropine were used to track variations in LV function in 14 subjects. Objective evaluation of wall motion was tested in 20 patients undergoing dobutamine stress testing. Regional fractional area change, displacement, and radial shortening were displayed as histograms and time curves. Global function was assessed by calculating magnitude and timing of peak ejection or filling rates and mean time of ejection or filling. Patterns of endocardial motion were consistent between normal subjects. Fractional area change and peak ejection rate decreased with esmolol and increased with dobutamine. Time to peak ejection and mean time of contraction were prolonged with esmolol and shortened with dobutamine. Using atropine, we proved that our findings with dobutamine were not secondary to its chronotropic effects. Dobutamine induced regional wall motion abnormalities in 10 patients in 38 segments diagnosed conventionally. Segmental analysis detected abnormalities in 36 of these 38 segments and in an additional 5 of 322 segments. CONCLUSIONS: Analysis of Color Kinesis images allows fast, objective, and automated evaluation of regional wall motion sensitively enough to evaluate clinical dobutamine stress data. This method has significant potential in the diagnosis of myocardial ischemia.

Adrenergic beta-Agonists↗
PubMed1997

Margatoxin binds to a homomultimer of K(V)1.3 channels in Jurkat cells. Comparison with K(V)1.3 expressed in CHO cells.

Voltage-gated potassium (K(V)) channels play key roles in setting the resting potential and in the activation cascade of human peripheral T lymphocytes. Margatoxin (MgTX), a 39-amino acid peptide from Centruroides margaritatus, is a potent inhibitor of lymphocyte K(V) channels. The binding of monoiodotyrosinyl margatoxin ([125I]MgTX) to plasma membranes prepared from either Jurkat cells, a human leukemic T cell line, or CHO cells stably transfected with the Shaker-type voltage-gated K+ channel, K(V)1.3, has been used to investigate the properties of lymphocyte K(V) channels. These data were compared with [125I]MgTX binding to heterotetrameric K(V) channels in rat brain synaptic plasma membranes [Knaus, H. G., et al. (1995) Biochemistry 34, 13627-13634]. The affinity for [125I]MgTX is 100-200 fM in either Jurkat or CHO/K(V)1.3 membranes, and the receptor density is 20-120 fmol/mg in Jurkat membranes or 1000 fmol/mg in CHO/K(V)1.3 membranes. In contrast to rat brain, [125I]MgTX binding to Jurkat and CHO/K(V)1.3 membranes exhibits an absolute requirement for K+, with no potentiation of binding by Na+. K(V)1.3 was the only K(V)1 series channel present in either CHO/K(V)1.3 or Jurkat plasma membranes as determined by immunoprecipitation of [125I]MgTX binding or by Western blot analyses using sequence-specific antibodies prepared against members of the K(V)1 family. The relative potencies of a series of peptidyl K(V) channel inhibitors was essentially the same for inhibition of [125I]MgTX binding to Jurkat, CHO, or rat brain membranes and for blocking 86Rb+ efflux from the CHO/K(V)1.3 cells, except that alpha-dendrotoxin was more potent at blocking binding to rat brain membranes than in the other assays. The characteristics of [125I]MgTX binding, the antibody profiles, and the effects of the peptidyl K(V) inhibitors all indicate that the [125I]MgTX receptor in Jurkat lymphocytes is comprised of a homomultimer of K(V)1.3, unlike the heteromultimeric arrangement of the receptor in rat brain.

Animals↗
PubMed1997

Maternal Phenylketonuria Collaborative Study (MPKUCS) offspring: facial anomalies, malformations, and early neurological sequelae.

Maternal phenylketonuria (PKU) in untreated women has resulted in offspring with microcephaly, mental retardation, congenital heart disease (CHD), and intrauterine growth retardation. The Maternal Phenylketonuria Collaborative Study (MPKUCS) was designed to determine the effect of dietary control of blood phenylalanine (Phe) during pregnancy in preventing damage to the fetus associated with untreated Maternal PKU. A cohort of offspring from MPKUS pregnancies was ascertained and examined to evaluate malformations, including CHD, craniofacial abnormalities, microcephaly, intrauterine and postnatal growth retardation, other major and minor defects, and early abnormal neurological signs. For analysis, the women were grouped according to their mean Phe levels in mumol/liter, < or = 360, 361-600, 601-900, or > 900, during critical gestational weeks of 0-8 (N = 203) and 8-12 (N = 190), and average for Phe exposure throughout pregnancy (N = 183). Frequencies of congenital abnormalities increased with increasing maternal Phe levels. Significant relationships included average Phe 0-8 weeks and CHD (P = 0.001); average Phe 8-12 weeks and brain, fetal, and postnatal growth retardation (P < 0.0005 for all), wide nasal bridge (P < 0.0005), and anteverted nares (P = 0.001); and average Phe exposure during the entire pregnancy and neurological signs (P < 0.0005). Although 14% of infants had CHD, none of the CHD occurred at 120-360 mumol/liter and only one (3%) at 361-600 mumol/liter. At levels of 120-360 mumol/liter, there were three infants (6%) with microcephaly, two (4%) with postnatal growth, and none with intrauterine growth retardation, in contrast to 85%, 51%, and 26%, respectively, with Phe above 900 mumol/liter. These data support the concept that women with PKU should begin a low-phenylalanine diet to achieve Phe levels of < 360 mumol/liter prior to conception and should maintain this throughout pregnancy.

Cohort Studies↗
PubMed1997

The relationship of genotype to phenotype in phenylalanine hydroxylase deficiency.

Seventy-two adults with phenylketonuria were evaluated to investigate the genotypic relationship to phenotype. Patient data were collected by chart review and medical follow-up as well as current psychological evaluation. Nineteen diagnosed neonatally had remained on a phenylalanine-restricted diet all their lives, whereas 34 who were also diagnosed on newborn screening had discontinued dietary restriction during childhood. Nineteen others who were born prior to newborn screening were diagnosed later than the newborn period on clinical grounds but have remained on dietary restriction. Comparison between intellectual ability, academic achievement, and mental illness was made with degree of diet control as defined by range of blood phenylalanine levels over time. Diet discontinuation in childhood did not significantly lower IQ per se but appeared to diminish academic achievement. The lowest IQ scores were associated with poor dietary restriction of phenylalanine in the diet during childhood. While there appears to be a strong genotypic relationship to phenotypic metabolic parameters in phenylketonuria, there does not seem to be a similar relationship to intellectual ability in adults. Mutation R408W was not strongly related to the occurrence of mental illness in this sample. We conclude that dietary restriction of phenylalanine neonatally and good control contributed to normal intellectual development. Continuation of dietary treatment into adulthood appeared to improve academic achievement in patients with severe phenylalanine hydroxylase mutations.

Adult↗
PubMed1997

[CHARTWEL-Bronchus (ARO 97-1): a randomized multicenter trial to compare conventional fractionated radiotherapy with CHARTWEL radiotherapy in inoperable non-small-call bronchial carcinoma].

BACKGROUND: The CHART-bronchus trial sponsored by the Medical Research Council showed an improvement in survival of 10% compared to conventional fractionation to 60 Gy when patients with inoperable non-small-cell lung cancer (NSCLC) were treated with CHART to 54 Gy. At present it is not known whether this survival advantage holds when the dose of conventional treatment is increased and whether CHART can be replaced by the more practicable CHARTWEEL (CHART-weekend less). PROTOCOL OF THE TRIAL: A randomized multicenter trial of definite radiotherapy in locally advanced inoperable NSCLC was designed (ARO 97-1, Arbeitsgemeinschaft Radioonkologie der Deutschen Krebsgesellschaft). Conventional fractionation to 66 Gy (5 weekly fractions of 2 Gy) is compared with CHARTWEEL to 60 Gy (15 weekly fractions of 1.5 Gy, Monday to Friday, interval between fractions > or = 6 hours, overall treatment time 2.5 weeks). The main endpoint of the trial is overall survival. It was calculated that an entry of 665 patients is needed to detect an improvement in 2-year survival of 10%, the actual time is estimated to be 5 years or less. The trial was activated on 1.9.1997.

Adult↗
PubMed1997

Effects of gas flow management on postintubation end-tidal anesthetic concentration and operating room pollution.

STUDY OBJECTIVE: To study how different anesthetic practices during the transition from anesthetic delivery by mask to endotracheal intubation affect end-tidal postintubation anesthetic concentration and operating room (OR) pollution. DESIGN: Prospective study. SETTING: Anesthesia research laboratory. MEASUREMENTS AND MAIN RESULTS: We studied four gas flow management practices: practice vaporizer off, only the anesthetic vaporizer was turned off; all off, oxygen (O2), nitrous oxide (N2O), and the vaporizer were turned off; gas off: O2 and N2O were turned off; and all on: neither the gas flows nor the vaporizer were turned off. A model of inhalational anesthetic induction was simulated by using an adult circle system attached to a reservoir bag ("artificial lung"). By using a fixed gas flow, we achieved an end-tidal N2O (ETN2O) concentration of 70% and end-tidal halothane (ETHal) concentration of 3%, then stopped mechanical ventilation and performed the four practices for a 30-second "intubation" period. During this time, the reservoir bag was disconnected from the circuit, and the gas volume exiting the circuit (pollution volume) was measured. After this 30-second disconnect period, the bag was reconnected to the anesthetic circuit, and the original ventilation, gas flows, and vaporizer setting were resumed. The anesthetic concentrations were measured at 10, 20, and 30 seconds after reconnection. For the vaporizer off practice, ETHal was low and did not return to equilibrium within 30 seconds (p < 0.05); ETN2O clinically was unaltered. In the all off practice, anesthetic concentrations were below equilibrium at 10, 20, and 30 seconds (p < 0.05). For the gas off practice, ETHal was slightly below equilibrium at all times; ETN2O was below equilibrium at 10, 20, and 30 seconds (p < 0.05). In the all on practice, end-tidal anesthetic concentrations were unchanged when compared with equilibrium (p > 0.05). Pollution volumes in the vaporizer off and all on practices were ten-fold higher than in the all off and gas off practices (p < 0.05). CONCLUSION: In a mechanical model of anesthetic induction, turning the gas flows off before "intubation" and leaving the vaporizer on (the gas off practice) maintained "postintubation" end-tidal drug concentrations close to "preintubation" equilibrium and minimized OR pollution.

Air Pollution, Indoor↗
PubMed1997

Influence of inspiratory capacity on bronchodilatation via Turbuhaler or pressurized metered-dose inhaler in asthmatic children: a comparison.

This study was designed to compare the bronchodilatatory effect of terbutaline inhaled through Turbuhaler (TH) or pressurized metered-dose inhaler (pMDI) in young asthmatics, and to assess the possible relationship between patients' inspiratory capacity and bronchodilatation for both devices. One hundred and eighteen asthmatics (aged 4 10/12-20 6/12 years) with bronchial obstruction (mean Vmax 50%: 59.5% pred, SD 17.8% pred) were allocated at random to two groups of 59 patients to inhale 0.5 mg terbutaline either by TH or by pMDI (and placebo by dummy of the other device). In- and expiratory spirometry and bodyplethysmography were conducted before and 10 min after inhalation. Bronchodilatation was effective [change in airways resistance (delta RAW) -50%, change in forced expiratory volume in 1 s (delta FEV1)+15%, delta Vmax 50% or 25% + 25% of baseline] in 41 of 59 patients with pMDI (69.5%) and 33 of 59 patients with TH (55.9%). The effect on Vmax 50% was significantly better with pMDI than with TH. Turbuhaler users with higher inspiratory flow [forced inspiratory volume in 1 s (FIV1), forced inspiratory flow at 50% vital capacity (FIF50)] reached better bronchodilatation, while bronchodilatatory effect was not correlated with inspiratory performance in MDI users. Peak inspiratory flow (PIF) did not correlate well with bronchodilatation by TH. When using TH for bronchodilatation, the effectiveness of terbutaline depends upon the degree of inspiratory capacity. This can lead to impaired bronchodilatatory effect in subgroups of obstructive young asthmatics with low inspiratory flow. In contrast, when using a pMDI, inspiratory capacity does not seem to influence the effectiveness of terbutaline.

Adolescent↗