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Biomedical subjects

E G Hahn

Publications and source records attributed to E G Hahn.

At least 19 recordsLinked to original sources

[A humidification system for CPAP therapy in obstructive sleep apnea--evaluation of the effectiveness in changing climatic environmental conditions].

OBJECTIVE: Upper airway dryness is a frequent side-effect of nasal continuous positive airway pressure (nCPAP) therapy in obstructive sleep apnoea syndrome (OSA). In this situation, heated humidification is often used. Therefore, the present study aimed to investigate the humidification performance--defined as the maximum achievable humidity in the tube system of the CPAP device--of a heated humidifier (HH) offered as CPAP accessories, as a function of ambient air conditions (humidity and temperature). PATIENTS AND METHODS: In 30 patients (22 male, 8 female, mean age 56.4 +/- 11.7 years) with OSA undergoing CPAP treatment, temperature (T) and relative humidity (RH) in the CPAP tube system were measured, with and without the HH Somnowave, until a steady state was achieved. At the same time, ambient T and RH in the examination room were recorded. T and RH were used to calculate the absolute humidity (AH). RESULTS: The conditions of the examination room during the examination nights were as follows: T = 21.9 +/- 2.8 degrees C (15.2-26.9), RH 46.5 +/- 11.9% (21.7-69.1) and AH 9.2 +/- 3.2 g/m3 (3.7-16.7). The steady state AH without HH was 9.6 +/- 3.0 g/m3 (4.1-15.4), that with HH (humidification performance) 23.2 +/- 2.8 g/m3 (19.1-29.9) (p < 0.001). CONCLUSION: Under the ambient conditions of humidity and temperature, commonly found in European bedrooms, the HH demonstrate a high humidification performance. Thus, it would appear that the HH is suitable for the treatment of dry upper airways under nCPAP therapy.

Adult↗

Role of leptin in ulcer healing.

Leptin was shown to exhibit similar to cholecystokinin (CCK) cytoprotective activity against acute gastric lesions, but its role in ulcer healing has not been examined. The aims of this study were: (1) to compare the effects of exogenous leptin to those of CCK on the course of healing of chronic gastric ulcers; (2) to study the gene and protein expression of leptin at the ulcer margin during ulcer healing; and (3) to assess the effects of leptin administration on the mucosal gene expression of main growth factor such as transforming growth factor alpha (TGFalpha). Gastric ulcers were produced in rats by the acetic acid method. Rats with ulcers were divided in following treatment groups: (1) vehicle; (2) leptin (10 microg/kg i.p.); (3) CCK (10 microg/kg s.c.); and (4) leptin or CCK with or without tyrphostin A46 (200 microg/kg i.p.), an inhibitor of epidermal growth factor (EGF)-receptor tyrosine kinase or NG-nitro-L-arginine (20 mg/kg i.g.), a blocker of nitric oxide synthase. Animals were euthanized 9 days after ulcer induction. The area of gastric ulcers and the gastric blood flow at the ulcer area were determined. In addition, mucosal biopsy samples were taken from the ulcer area for histological evaluation as well as for the determination of mRNA and protein expression for leptin and constitutive nitric oxide synthase (cNOS) and inducibile nitric oxide synthase (iNOS) by reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blot, respectively. In addition, the gene expression for TGFalpha was analyzed by RT-PCR. Both leptin and CCK reduced significantly the ulcer area as compared to vehicle-treated group by approximately 50%. The treatment with tyrphostin or N(G)-nitro-L-arginine reversed in part the acceleration of ulcer healing by leptin and CCK. The expression of leptin mRNA and protein was significantly increased at the ulcer edge. The leptin-induced acceleration of ulcer healing was associated with increased expression of transcripts for TGFalpha as well as increased mRNA and protein expression for cNOS and iNOS at the ulcer margin. We conclude that leptin accelerates ulcer healing by mechanisms involving the up-regulation of TGFalpha and increased production of nitric oxide due to up-regulation of cNOS and iNOS in the ulcer area.

Animals↗

Luminal Nalpha-methyl histamine stimulates gastric acid secretion in duodenal ulcer patients via releasing gastrin.

Nalpha-methyl histamine is an unusual histamine metabolite which is produced in the stomach infected by Helicobacter pylori and which was shown in animals to stimulate gastric acid secretion and to release gastrin in vitro isolated G-cells, but no information is available regarding its influence on gastric secretion and gastrin release in duodenal ulcer patients before and after H. pylori eradication. In this study, we compared the effects of intragastric administration of single or graded doses of Nalpha-methyl histamine on gastric acid secretion and plasma gastrin levels in 16 male duodenal ulcer patients (aging from 35 to 48 years and weighing 65-82 kg) before and after the eradication of H. pylori. Furthermore, the gastric luminal histamine and gastrin contents were determined before and after H. pylori eradication. In H. pylori-infected duodenal ulcer patients, the intragastric application of Nalpha-methyl histamine failed to affect gastric acid secretion or plasma gastrin levels. Following eradication of H. pylori, gastric luminal histamine and gastrin, and both basal gastric acid secretion and plasma gastrin levels, were significantly reduced. Nalpha-methyl histamine given intragastrically in graded doses to such H. pylori-eradicated duodenal ulcer patients was found to increase dose-dependently gastric acid output reaching at a dose of 5 mg, about 80% of histamine maximum induced by i.v. infusion of 25 microg/kg h of histamine dihydrochloride. We conclude that Nalpha-methyl histamine is a potent luminally active stimulant of gastrin release and gastric acid secretion in H. pylori-eradicated patients when luminal histamine is low but is not effective in H. pylori infected patients when luminal histamine is enhanced, possibly due to desensitization of gastrin (G-cells) and acid-producing (parietal) cells by Nalpha-methyl histamine produced excessively in H. pylori-infected stomach.

Adult↗

Changes in quality of life after medical intensive care.

OBJECTIVES: To determine outcome and changes in health-related quality of life (QOL) in medical intensive care patients. DESIGN AND SETTING: Prospective comparison of QOL before and 6 months after intensive care unit (ICU) admission in a 12-bed noncoronary medical ICU of a university hospital. PATIENTS: All 325 consecutively admitted adult patients who spent at least 24 h on the ICU were eligible. MEASUREMENTS AND RESULTS: QOL measurements were collected before and 6 months after ICU admission. Comorbidity classified by the Charlson index was 2.44 +/- 1.96. Mean stay in the ICU was 10.4 +/- 15.1 days, mean Acute Physiology and Chronic Health Evaluation II score was 23 +/- 10. Cumulative mortality was: ICU 24 %, hospital 34 %, 6 months 43 %. Relative to baseline, follow-up interviews of 185 survivors revealed no significant changes in the overall QOL score (p = 0.93). The subscales basic physiological activities (p = 0.07) and normal daily activities (p = 0.15) showed a nonsignificant deterioration. A significant improvement was noted for the domain emotional state (p = 0.013). CONCLUSIONS: Six months after admission to a medical ICU most survivors had regained their preadmission health-related QOL. Multivariate analysis showed that preadmission QOL, age, and severity of illness were most strongly associated with follow-up QOL. Of the survivors 86 % were living at home, and all but one of those previously in employment had returned to their former work. Most patients (94%) would undergo ICU treatment again if necessary.

Adolescent↗

Proliferating bile duct epithelial cells are a major source of connective tissue growth factor in rat biliary fibrosis.

Connective tissue growth factor (CTGF) is a downstream mediator of transforming growth factor-beta1 (TGF-beta1) and thus a potential target for antifibrotic treatment strategies. CTGF is up-regulated in disorders such as atherosclerosis, scleroderma, and fibrosis of kidneys and lungs. We investigated the temporospatial expression patterns of CTGF and TGF-beta1 mRNA in rat livers with acute fibrogenesis (after a single dose of CCl(4)) and with advanced fibrosis (6 weeks after complete bile duct occlusion). Multiprobe ribonuclease protection assay revealed increasing TGF-beta1 and CTGF mRNA levels 6 hours after injection of CCl(4), with peak levels after 72 hours. In biliary fibrosis TGF-beta1 and CTGF mRNA levels increased fourfold and sevenfold, respectively (P: < 0.001). In situ hybridization combined with cell-specific markers revealed CTGF transcripts in desmin-positive cells after a single dose of carbon tetrachloride, whereas no transcripts were found in normal livers. In biliary fibrosis, however, proliferating bile duct epithelial cells were the predominant source of CTGF mRNA. We conclude that in rat liver fibrogenesis CTGF is up-regulated in close association with TGF-beta1 and that, contrary to a previous report, not solely hepatic stellate cells but activated bile duct epithelial cells are the main source of this profibrogenic factor.

Acute Disease↗

Sensitivity of a simplified forced oscillation technique for detection of upper airway obstruction.

The sensitivity of a simplified variant of forced oscillation technique (FOT) was studied for assessment of dynamic upper airway obstruction during nasal continuous positive airway pressure (nCPAP) therapy for obstructive sleep apnoea (OSA). The airway impedance P[FOT] was measured by FOT and the oesophageal pressure (P(oes)) was recorded during stable stage II sleep in 11 patients with OSA. The CPAP level was initially set high enough to completely abolish upper airway obstruction. To induce gradually increasing upper airway re-obstruction, the CPAP pressure was then lowered stepwise. Thirty six such manoeuvres were analysed, blind, to define the first inspiration at which upper airway re-obstruction was detectable by analysis of P[FOT](t(FOT)) and by P(oes)(t(oes)), respectively. On seven occasions t(FOT) and t(oes) occurred together, in the remaining 29 cases t(FOT) preceded t(oes) with a mean latency of 6.0+/-7.7 (0-32) breath cycles. In no case did t(oes) preceed t(FOT). FOT is a highly sensitive tool for the assessment of incipient upper airway obstruction during nCPAP therapy.

Aged↗

CEA and CA 19-9 measurement as a monitoring parameter in metastatic colorectal cancer (CRC) under palliative first-line chemotherapy with weekly 24-hour infusion of high-dose 5-fluorouracil (5-FU) and folinic acid (FA).

BACKGROUND: There have been contradictory reports on the benefit of CEA and CA 19-9 measurements in patients with metastatic colorectal cancer using palliative chemotherapy. The object of this study was to examine the diagnostic accuracy of monitoring of palliative chemotherapy by means of CEA and CA 19-9. PATIENTS AND METHODS: The tumour markers CEA and CA 19-9 were subjected to serial measurement in patients with metastatic colorectal cancer (n = 90) using palliative first-line chemotherapy with weekly 24-hour infusion of high-dose 5-FU with FA and were compared with objective response according to WHO criteria. 85 patients could be evaluated. 43 patients (51%) initially had elevated CEA (> or = 10 ng/ml) and 33 patients (39%) elevated CA19-9 (> or = 50 IE/ml). In 24 patients (28%), both markers were initially increased. With CEA positive patients, 143 cycles of chemotherapy were carried out, which showed the following response in the various cycles: 21 episodes with progressions (ePD), 69 episodes with no change (eNC), 53 episodes with partial/complete remission (ePR/eCR). With CA 19-9 positive patients, 100 cycles of chemotherapy were carried out with the following results: 21 episodes with progressions (ePD), 48 episodes with eNC, and 31 episodes with ePR/eCR. RESULTS: A CEA rise by at least 50% differentiated between ePD versus eNC/ePR/eCR with a sensitivity of 76% and specificity of 90%. With CEA decreases of at least 30% in 99% of these patient episodes (78 of 79), a tumour progression could be excluded. Patients with an initial drop in CEA after the first cycle of chemotherapy of at least 50% of the initial level had a significantly higher probability of achieving an ePR/eCR in further therapy (relative risk 2.9; P = 0.002). With an CA 19-9 increase of at least 30%, a sensitivity progression of 62% and a specifity of 90% could be calculated. A CA 19-9 decrease of at least 60% excludes a progression in 95% of the patient episodes. CONCLUSIONS: A CEA or CA 19-9 rise is only conditionally appropriate for recording progressions. A progression however, can be excluded with falling levels with high diagnostic accuracy, in which CEA offers a greater degree of certainty than CA 19-9. With a drop in CEA 79 of 143 (= 55%) of the CT scans could be saved, in which case 78 of 79 patient episodes (99%) were correctly assessed as 'no progression'. In patients with an increased CEA and CA 19-9 the CEA determination is sufficient for the further monitoring. A confirmation of these results by multicenter trials can result in a considerable decrease of monitoring costs for palliative treatment.

Adult↗

Quantitative testing of liver function in patients with cirrhosis due to chronic hepatitis C to assess disease severity.

BACKGROUND/AIMS: Quantitative testing of liver function (QTLF) may allow a prognostic assessment of patients with various liver diseases. However, there are insufficient data about patients with liver cirrhosis due to hepatitis C. PATIENTS/METHODS: 86 consecutive patients (58 males, 28 females, age: 48.3 +/- 11.7 years) with chronic hepatitis C (HCV RNA pos.) underwent sonographically guided liver biopsy to confirm the diagnosis of cirrhosis. QTLF included aminopyrine breath test (microsomal liver function), galactose elimination capacity (cytosolic liver function), sorbitol clearance (liver plasma flow) and indocyanine green clearance (liver perfusion). Values were correlated with the Child-Pugh classification. RESULTS: 55% of the patients (n=47) had cirrhosis of Child-Pugh grade A, 28% of grade B (n=24) and 17% of grade C (n=15). QTLF showed a steady decrease from Child-Pugh grade A to grade B and to grade C. Contrary to markedly reduced tests of metabolic liver function in Child-Pugh grade patients, surrogate tests of hepatic perfusion were at the lower normal limit. All QTLF were significantly reduced in Child-Pugh grade B and C patients compared to healthy controls. Differences between the three Child grades were significant. CONCLUSION: In patients with cirrhosis due to hepatitis C, QTLF correlated inversely with Child-Pugh grades. Since in cirrhosis of grade A, surrogate tests of hepatic perfusion remained at the lower normal limit, whereas those of metabolic function were decreased, QTLF may be a tool to predict prognosis or complications in early cirrhosis due to chronic hepatitis C.

Aminopyrine↗

Adverse drug reactions in patients with gastroenterological diseases: does age increase the risk?

BACKGROUND: It has been claimed that the risk of adverse drug reactions increases with age. However, only limited data exist for disease-group specific risks and none for patients with liver and gastrointestinal diseases. AIMS: To determine the incidence and characteristics of adverse drug reactions and the physicians' awareness of adverse drug reactions. METHODS: During a 7-month period, a prospective survey of 532 male patients (158 aged 65 years or older; 30%) was conducted on a hepatogastroenterological ward of a tertiary-care university hospital, using intensive bedside and computer-assisted drug surveillance methods. RESULTS: No difference was found in the overall rate of adverse drug reactions between older and younger patients (25.9% vs. 24.2%) during 6213 treatment days. However, a significantly higher risk for developing adverse drug reactions could be shown for the elderly with biliary tract diseases (P < 0.01). Independently of age, patients suffering from gastric ulcers, acute episodes of pancreatitis, cholangitis or inflammatory bowel diseases were at high risk of adverse drug reactions. Adverse drug reaction-associated mortality was encountered in four elderly and none of the younger patients. Secondary pharmacological effects and drug toxicity were the main types of adverse drug reactions for both age groups. Although 75.3% of the adverse drug reactions were predictable, only 37.5% of all adverse drug reactions were recognized by the staff physicians. CONCLUSION: In hepatogastroenterological patients, advancing age was not associated with an overall increased risk of adverse drug reactions except for patients with biliary tract diseases. In the elderly, adverse drug reactions were more severe and carried higher mortality. Guidelines and educational programs should be developed to increase the awareness of adverse drug reactions and their prevention, especially in high risk patients and, thus, to improve patient outcomes.

Age Factors↗

Absence of efficacy of subcutaneous antisense ICAM-1 treatment of chronic active Crohn's disease.

BACKGROUND & AIMS: ISIS-2302, an antisense oligonucleotide directed against intercellular adhesion molecule 1, was effective in steroid refractory Crohn's disease in a pilot trial. The aim of this study was to investigate safety and efficacy of ISIS-2302 in chronic active Crohn's disease (CACD). METHODS: A dose-interval, multicenter, placebo-controlled trial was conducted in 75 patients with steroid-refractory CACD (Crohn's Disease Activity Index [CDAI], 200-400). The primary endpoint was steroid-free remission (CDAI <150) at week 14. RESULTS: Only 2 of 60 (3.3%) ISIS-2302-treated and no placebo patients reached the primary endpoint. Steroid-free remission at week 26 (secondary endpoint) was reached in 8 of 60 (13.3%) active treatment and 1 of 15 (6.7%) placebo patients. A greater proportion of ISIS-2302-treated than placebo patients achieved a steroid dose <10 mg/day at weeks 14 and 26 (48.3% vs. 33.3% and 55.0% vs. 40.0%, respectively, and a glucocorticoid dose of 0 mg [prednisone equivalent] at week 26 [23.3% vs. 6.7%, respectively]). Treatment with ISIS-2302 was safe. The most common side effects were injection site reactions in the active treatment group (23% in ISIS-2302-treated patients vs. none in placebo patients). No statistically significant differences in the frequency of side effects were detected between dose groups. CONCLUSIONS: The trial did not prove clinical efficacy of ISIS-2302 based on the primary endpoint. Positive trends were observed in some of the secondary endpoints.

Adult↗

Weekly 24-h infusion of high-dose 5-fluorouracil (5-FU) with folinic acid (FA) in adjuvant therapy of colon cancer.

After curative resection (R-0) of primary colon cancer or curative metastases resection, the efficacy, toxicity and compliance of a weekly 24-h infusion of high-dose 5-FU with folinic acid was examined in a prospective feasibility trial. From June 1995 to June 1997, 19 patients were included, 11 patients with UICC stage III and 8 patients with UICC stage IV colon cancer. The patients received weekly 500 mg/m2 of calcium folinic acid (Rescuvolin) as a 1-2 h-infusion on an outpatient basis following a 24-h infusion of 2,000 mg/m2 5-FU via a pump system (intermate LV5 Baxter). The adjuvant therapy was administered for 6 months. 90% of the patients received the planned 18 chemotherapy applications. The total 5-FU dose given to each patient amounted to 34.4 g/m2 in 6 months, thus corresponding to 95% of the planned 5-FU total dose. The main toxicity was diarrhea CTC toxicity grade 3 in the case of 16% of the patients. After a median follow-up of 51 months (range: 37-59 months), 82% of the patients (9 out of 11) with stage III remained free of recurrence. The 2 cases of recurrence belonged to the pN2 subgroup. In stage IV only 12% of the patients (1 out of 8) remained free of recurrence. On an adjuvant basis, a weekly 24-h infusion of high-dose 5-FU with folinic acid is accompanied by a good complicance and a high-dose intensity of 5-FU. Now it is tested within randomized phase III trials of the "Arbeitsgemeinschaft Gastroenterologische Onkologie (AGO)" of the "Deutsche Gesellschaft für Verdauungs- und Stoffwechselerkrankungen" for UICC stage III colon cancer. Concerning stage IV, adjuvant therapy was not effective, a fact that seems to justify new drugs and new therapeutic strategies.

Adult↗

[Liver toxicity of drugs of plant origin].

Herbal drugs are widely used and often contain highly active pharmacological compounds. Recently, reports have mounted about hepatotoxicity of herbal remedies which ranges from mild liver enzyme alterations to chronic liver disease and liver failure. Hepatotoxicity of Chinese herbs has been recognized, e.g. during treatment of patients with atopic eczema. However, the toxic compounds remain to be determined. Hepatic veno-occlusive disease may result from pyrrolizidine alkaloids which are contained in numerous plants worldwide. Teucrium chamaedrys, commonly referred to as germander, may cause hepatitis and even liver cirrhosis. Significant hepatotoxicity has also been observed after the ingestion of chaparral. Recently, greater celandine, which is widely used for biliary disorders and dyspepsia, was identified as a cause of cholestatic hepatitis. Hepatotoxic reactions have also been observed after the ingestion of Atractylis gummifera, Callilepsis laureola, Senna, Kavapyrone and Pulegium. The aim of this review is to summarize potentially hepatotoxic herbal remedies, to further elucidate their mechanisms of toxicity and thereby underline the likelihood of plants to be the cause of liver damage.

Chemical and Drug Induced Liver Injury↗

Release of mast cell tryptase from human colorectal mucosa in inflammatory bowel disease.

BACKGROUND: Histologic detection of mast cells cannot adequately reflect their function and state of activation, since degranulated mast cells may escape from histologic assessment. To better define the role of mast cells in inflammatory bowel disease, the spontaneous secretion of mast cell tryptase, a highly mast cell specific protease, was measured from colorectal samples. METHODS: After detection of the initial basal tryptase release, gut mucosal samples were incubated in a modified Hanks/RPM1 medium using a mucosa oxygenation system. Spontaneous tryptase secretion from 153 viable samples of 22 controls, 30 patients with Crohn disease (CD) and 19 with ulcerative colitis (UC) was followed over 4 h. Tryptase was measured by radioimmunoassay. RESULTS: The rates of the initial basal tryptase release revealed that mast cell activation occurs during active inflammation in CD and UC. While the time course of tryptase release was similar in all three groups, spontaneous tryptase secretion (over 4 h) was found to be significantly enhanced and prolonged only in UC (P < 0.01 compared to controls), but not in CD. CONCLUSIONS: This study provides clear evidence from viable endoscopic colorectal samples that mast cell mediators were secreted during active inflammation in CD and UC. However, the extent of mast cell involvement and activation differs considerably between CD and UC. Significantly increased rates of tryptase secretion were found both in non-inflamed and inflamed tissue of UC, indicating that mast cell involvement is a typical feature of UC.

Adult↗

Risperidone-induced cholestatic hepatitis.

Risperidone, a widely used atypical and potent neuroleptic drug, is assumed to induce fewer hepatic side-effects than phenothiazine anti-psychotics. Recently, we observed a case of risperidone-induced cholestatic hepatotoxicity. A 37-year-old male developed a rapid increase in liver enzymes and cholestatic parameters after starting treatment with risperidone for paranoid psychosis. Work-up for other potential aetiologies was negative. The results of a percutaneous liver biopsy were consistent with drug-induced liver injury and cholestasis. Over the course of one month after the discontinuance of all anti-psychotic agents, the liver function test results returned to near-normal values. This observation supports the need to monitor cholestatic parameters in addition to liver function enzymes during initiation and the first weeks of risperidone intake.

Adult↗

Immunoglobulin E and eosinophilic cationic protein in segmental lavage fluid of the small and large bowel identify patients with food allergy.

OBJECTIVE: Members of the general population often assume that they suffer from food allergy, but the true prevalence is low. Testing for the diagnosis of food-related hypersensitivity entails laborious procedures, including GI endoscopy. Our objective was to develop an endoscopic screening approach for food allergy. METHODS: Endoscopically guided segmental lavage was performed in 11 patients with GI allergy and in 20 controls during lower GI endoscopy of the terminal ileum, the coecum, and the rectosigmoid. Eosinophilic cationic protein (ECP) and protein were measured in native lavage fluid, and immunoglobulin E (IgE) was also measured after a 10-fold lavage concentration. RESULTS: IgE/protein in lavage fluid from the coecum (0.055 +/- 0.068 U/mg vs 0.003 +/- 0.012 U/mg; p = 0.001) and the rectosigmoid (0.134 +/- 0.170 U/mg vs 0.019 +/- 0.042 U/mg; p < 0.05) was significantly elevated in patients with GI allergy. ECP/protein was significantly elevated at the terminal ileum (22.95 +/- 37.67 microg/mg vs 7.09 +/- 7.68 microg/mg; p < 0.05) and the rectosigmoid (23.66 +/- 19.43 microg/mg vs 11.97 +/- 16.39 microg/mg; p < 0.05). The combined use of GI lavage IgE and ECP as a diagnostic test for food allergy resulted in a sensitivity of 91% and a specificity of 80%. CONCLUSIONS: In endoscopically guided segmental lavage fluid, IgE and ECP/protein are increased in patients with food allergy. These measurements seem to offer an attractive diagnostic tool and may serve as a screening method.

Adult↗

Reproducibility of a standardized titration procedure for the initiation of continuous positive airway pressure therapy in patients with obstructive sleep apnoea.

BACKGROUND: Manual titration of continuous positive airway pressure (CPAP) under polysomnographic control is the method most commonly employed to establish the minimal effective pressure (P(eff)) for the treatment of the obstructive sleep apnoea syndrome (OSA). To date, however, the reproducibility of P(eff) titrated in this way has not been investigated in any detail. OBJECTIVES: The present study aims to establish the reproducibility of P(eff) determined by manual titrations of CPAP under polysomnographic control in the sleep lab. METHODS: In a group of 50 patients (5 women), with a mean (SD) apnoea-hypopnoea index of 39.3 (21.8), apnoea index of 28.1 (20.9) and oxygen desaturation index of 39.3 (22.6), with newly diagnosed OSA, manual titration of CPAP was performed on two consecutive nights using the following standard titration protocol: starting at 4 mbar, CPAP was increased by steps of 1 mbar at intervals of at least 5 min, until no signs of airway obstruction could be seen, and arousals were no longer elicited. When no airway obstruction was detected over a period of 30 min, the pressure was lowered once during the night in steps of 1 mbar at intervals of at least 10 min, until obstructive events reappeared, whereupon the pressure was again increased as described above, until, once more, no signs of airway obstruction and no arousals occurred. The second titration was carried out in a blind manner, that is the lab technician did not know the results of the first pressure titration. RESULTS: The mean (SD) P(eff) for all titrations was 8.1 mbar (2.9). A high level of correlation was found between the P(eff) titrated on the first night and that titrated on the second night (Spearman correlation coefficient = 0.89). In a few individual cases, however, differences of up to 3 mbar were found between P(eff) on the first night and P(eff) on the second night. On average, the P(eff) measured on the second night was 0.5 mbar (SD = 1.3, range: -2.0 to 3.0 mbar) higher than that of the first night. CONCLUSIONS: With standardization of the manual titration of CPAP, P(eff) is readily reproducible. In individual cases, however, a difference of as much as 3.0 mbar between the two titrations is possible.

Adult↗