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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Nasal continuous positive airway pressure (nCPAP) therapy in obstructive sleep breathing disorders].

The therapeutic efficacy and the incidence of significant side effects of nasal continuous positive airway pressure (nCPAP) treatment was investigated in 1140 patients with sleep-related apnoea (1089 men, 51 women; mean age 53.2 +/- 9.2 [16-84] years). All had been treated for the condition with nCPAP at the Marburg University Medical Polyclinic between 1986 and 1992. The mean number of attacks of apnoea and/or hypopnoea per hour of sleep ("respiratory disturbance index", RDI) was 45.8 +/- 25.6 before treatment and 3.5 +/- 4.8 under nCPAP. 21.1% of patients had an apnoea index of no more than 10/h. 11.6% an RDI of no more than 15/h. The average airway pressure was 8.7 (3-18) cm H2O. The treatment was successful in 1023 patients and these decided to continue the treatment long-term. The RDI could not be lowered under 10/h in 63 patients, while 4 patients declined ambulant treatment despite the demonstrated efficacy of nCPAP. Three patients developed acute left ventricular failure in the initial phase of the treatment, while in another 16 patients long-persisting central hypoventilation was shown to occur. These data show that treatment with nCPAP can be employed for all degrees of severity of obstructive sleep apnoea. However, because of the potentially life-threatening side effects, the introduction of the treatment must be undertaken in the sleep laboratory under continuous monitoring.

Adolescent↗
PubMed1995

Randomized controlled multicentre study of the prevention of complications by octreotide in patients undergoing surgery for chronic pancreatitis.

A randomized double-blind placebo-controlled multicentre trial was carried out in 247 patients undergoing major elective surgery for chronic pancreatitis to clarify whether the perioperative application of octreotide prevents postoperative complications. Eleven complications were defined, including death, anastomotic leakage, pancreatic fistula, abscess, fluid collection, shock, sepsis, bleeding, pulmonary insufficiency, renal insufficiency and postoperative pancreatitis. A total of 124 patients underwent pancreatic head resection, 55 left resection, 61 pancreaticojejunostomy and seven had other procedures. The overall mortality rate was 1.2 per cent (octreotide group 1.6 per cent, placebo group 0.8 per cent [corrected] (P not significant)). The postoperative complication rate in the octreotide group was 16.4 per cent (20 of 122 patients) and in the placebo group 29.6 per cent (37 of 125) (P < 0.007). The perioperative application of octreotide substantially reduces the risk of postoperative complications in patients undergoing major pancreatic surgery for chronic pancreatitis.

Adult↗
PubMed1995

Hypertrophic cardiomyopathy: a desensitized cardiac beta-adrenergic system in the presence of normal plasma catecholamine concentrations.

Only few data are available concerning the biochemical and functional state of the beta-adrenergic system in hypertrophied human myocardium. The present study was to investigate the myocardial beta-adrenergic signal transduction system in hypertrophic obstructive cardiomyopathy (HOCM). Thin myocardial strips were prepared from surgically excised, septal myocardium from 7 patients with HOCM and their force of contraction was measured in vitro. The positive inotropic effects of calcium and dihydro-ouabain, both acting independently of beta-adrenoceptors and cAMP, were similar in these preparations to those, previously published, seen with nonfailing myocardium. In contrast, the beta-adrenoceptor agonist isoprenaline and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) had reduced positive inotropic effects. Their EC50-values were about 10 fold higher than the respective EC50-values published for nonfailing myocardium. The positive inotropic potencies of isoprenaline and IBMX were reduced in HOCM by as much as they were in the additionally investigated myocardium from 6 patients with severe mitral regurgitation (MR, NYHA III). In order to clarify whether the functional alterations are related to changes in the beta-adrenoceptors, beta-adrenoceptor density and beta 1: beta 2-adrenoceptor subtype distribution were determined in the same myocardium using 125I-Iodocyanopindolol saturation binding. Myocardial beta-adrenoceptor density was reduced to 68% in HOCM and to 56% in MR compared to nonfailing myocardium controls (NF: 64.8 +/- 6.5 fmol/mg protein). In HOCM, this reduction was due to a selective down regulation of beta 1-adrenoceptors (24.9 +/- 3.7 fmol/mg protein vs NF: 46.4 +/- 6.8 fmol/mg protein, P < 0.05), whereas beta 2-adrenoceptor density was unchanged (19.0 +/- 1.9 fmol/mg protein vs NF: 18.4 +/- 3.3 fmol/mg protein, n.s.). In MR both beta-adrenoceptor subtypes were reduced (beta 1: 26.9 +/- 1.4 fmol/mg protein, beta 2: 9.6 +/- 1.7 fmol/mg protein; both P < 0.05 vs NF). Electrochemically determined plasma catecholamine levels were elevated in MR. However, plasma catecholamine levels were normal or slightly below normal in HOCM. In summary, myocardial beta-adrenoceptors are downregulated and their function is impaired in HOCM. This desensitization is not caused by a negative feedback regulation due to increased plasma catecholamines. The present results show that the desensitizations of the beta-adrenergic system associated with HOCM has characteristics that indicate a major deviation in its development from that of the beta-adrenergic desensitization previously described to occur in congestive heart failure.

Adult↗
PubMed1995

The effects of prostacyclin on gastric intramucosal pH in patients with septic shock.

OBJECTIVE: To investigate whether infusing prostacyclin (PGI2) in patients with septic shock improves splanchnic oxygenation as assessed by gastric intramucosal pH (pHi). DESIGN: Interventional clinical study. SETTING: Surgical ICU in a university hospital. PATIENTS: 16 consecutive patients with septic shock according to the criteria of the ACCP/SCCM consensus conference all requiring norepinephrine to maintain arterial blood pressure. INTERVENTIONS: All patients received PGI2 (10 ng/kg x min) after no further increase in oxygen delivery could be obtained by volume expansion, red cell transfusion and dobutamine infusion. The results were compared with those before and after conventional resuscitation. The patients received continuous PGI2 infusion for 33-32 days. MEASUREMENTS AND RESULTS: O2 uptake was measured directly in the respiratory gases, pHi was determined by tonometry. Baseline O2 delivery, O2 uptake and pHi were 466 +/- 122 ml/min.m2, 158 +/- 38 ml/min.m2, and 7.29 +/- 0.09, respectively. While O2 uptake remained unchanged, infusing PGI2 increased O2 delivery (from 610 +/- 140 to 682 +/- 155 ml/min.m2, p < 0.01) and pHi (from 7.32 +/- 0.09 to 7.38 +/- 0.08, p < 0.001) beyond the values obtained by conventional resuscitation. While 9 of 11 patients with final pHi > 7.35 survived, all patients with final pHi < 7.35 died (p < 0.01). CONCLUSIONS: Infusing PGI2 in patients with septic shock increases pHi probably by enhancing blood flow to the splanchnic bed and thereby improves splanchnic oxygenation even when conventional resuscitation goals have been achieved.

Adult↗
PubMed1995

[Quantification of relevant measurements of the petrous bone with computerized tomography before cochlear implant operation].

In this investigation the following anatomical measurements of the petrous bone preceding cochlear implant were evaluated using computed tomography (CT): the width of the basal coil of the cochlea, the thickness of the promontory, the distance between the sigmoid sinus and the posterior wall of the external auditory canal and the thickness of the squamous part of the temporal bone in the area of operation. Initially it was necessary to ascertain how accurately CT represents the anatomical structures of the petrous bone. The procedure of CT investigation in adult patients was simulated using the base of a skull. The CT plane in which the above mentioned measurements preceding cochlear implant can be made was represented and measurements were taken. Subsequently the same plane in CT was represented macroscopically with a specially developed method. The results show that anatomical structures measured in CT are magnified by 5% in contrast to the original. This magnification is presumably attributable to the computing of connective tissue which is adjacent to bone and the incapacity of CT to image structures of different density in the same voxel. In the second part of this investigation we evaluated 66 preoperative CT's of patients who were given a cochlear implant. The results must be adjusted by 5% to allow for this error in magnification. In conclusion a preoperative radiologic evaluation of the anatomical structures relevant to cochlear implant is without doubt tenable. Also the negligible difference between CT and the anatomical original requires no operative consequences. Because cochleostomy is carried out with a diamond burr of 1 mm diameter, a tenth of a millimeter is negligible according to our experience.

Adolescent↗
PubMed1995

Analysis of proteins that interact with the IL-2 regulatory region in patients with rheumatic diseases.

In order to investigate transcriptional regulation of lymphokine genes in rheumatic diseases, peripheral blood mononuclear cells from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and systemic sclerosis (SSc) were analysed for expression of DNA-binding proteins. Nuclear extracts prepared from unstimulated and mitogen-activated cells were studied for their ability to bind to 32P-labelled oligonucleotides containing the AP-1, NF-AT, NF-B and CD28RC sites of the IL-2 promoter. Using gel mobility-shift assay, detection of protein binding to the AP-1 site was reduced in SLE compared with controls. NF-AT binding activity was enhanced in all groups of patients, and was associated with measures of disease activity in RA. In addition, SSc patients showed increased NF-kappa B binding activity. Altered patterns of DNA-binding proteins suggest disturbed intracellular signalling which may contribute to abnormal lymphokine production in rheumatic diseases.

Adult↗
PubMed1995

Intrathoracic pressure changes and cardiovascular effects induced by nCPAP and nBiPAP in sleep apnoea patients.

The effect of nasal continuous positive airway pressure (nCPAP) and nasal bi-level positive airway pressure (nBiPAP) on intrathoracic pressure and haemodynamics during wakefulness was studied in a group of nine patients with severe sleep apnoea. No patient took cardiovascular medication. Patients were studied with a Swan Ganz catheter, an arterial line and an oesophageal balloon. nCPAP and nBiPAP were applied in the following pressure sequence: 5, 10 and 15 cm H2O of CPAP and 10/5 and 15/10 cm H2O of nBiPAP. Measurements were made at the end of a 5-min period at each pressure level. Intrathoracic pressure was noted to increase to a level of approximately 50% of the pressure delivered at the mask. At a CPAP of 10 cm H2O and above, as well as at BiPAP of 10/5 or higher, there was a decrease in cardiac output (CO) and cardiac index (CI). CI fell below the normal value in two of the patients. Transmural pulmonary artery pressure (PPAtm) decreased at a CPAP of 15 cm H2O and at both BiPAP levels. Transmural right atrial pressure (PRAtm) decreased at both BiPAP levels. There were no differences in CO, CI, PPAtm and PRAtm between nCPAP and nBiPAP at equal inspiratory pressures. SaO2 increased during BiPAP 15/10 cm H2O, whereas heart rate and arterial blood pressure did not change significantly. The data presented here are consistent with the literature on positive end-expiratory pressure (PEEP) applied via intratracheal tube and are likely to be due to a reduced venous return. It is concluded that nasally applied positive pressure may have acute negative effects on cardiac function in patients with sleep apnoea.

Journal Article↗
PubMed1995

Ventilatory response to isocapnic hyperoxia.

Breathing O2 for up to 1 h has been shown to either not influence or slightly increase (6-13%) minute ventilation. However, end-tidal PCO2 was not kept constant in these experiments. In nine healthy men, we studied the ventilatory, blood pressure, and heart rate responses to 30 min of normobaric hyperoxia (50% O2) at isocapnic conditions. Hyperoxia led to a 60% increase in mean minute ventilation (P = 0.002), largely due to an increase in mean tidal volume from 0.66 +/- 0.04 (SE) to 0.88 +/- 0.05 liter (P = 0.007). Fifteen minutes after the termination of hyperoxia, minute ventilation was still increased (P = 0.02) compared with baseline, although it was reduced compared with hyperoxia (P = 0.02). Arterial blood gas analyses in six subjects before and during hyperoxia showed an increase in arterial PO2 and O2 saturation but no change in arterial PCO2 or pH. Hyperoxia induced no changes in arterial blood pressure or heart rate. We conclude that 1) isocapnic hyperoxia stimulates respiration markedly, an effect that is approximately five times higher than previously measured; 2) the increase in ventilation induced by hyperoxia does not affect arterial blood pressure and heart rate; and 3) in experiments using hyperoxia, its effect on breathing and subsequently on PCO2 has to be taken into account.

Adult↗
PubMed1995

Evaluation of liver function tests to predict operative risk in liver surgery.

Despite numerous studies in the past it is not possible yet to predict postoperative liver failure and safe limits for hepatectomy. In this study the following liver function tests ICG-ER (indocyaninegreen elimination rate), GEC (galactose elimination capacity) and MEGX-F (monoethylglycinexylidid formation) are examined with regard to loss of liver tissue and prediction of operative risk. Liver function tests were assessed in 20 patients prior to liver resection and on the 10th. postoperative day. Liver and tumor volume were measured by ultrasound and pathologic specimen and the parenchymal resection rate was calculated. In patients without cirrhosis (n = 10) ICG-ER and MEGX-F remained unchanged after resection, GEC was reduced but did not correspond to the resection rate. Patients with cirrhosis (n = 10) had a significantly lower ICG-ER and GEC before resection than patients without cirrhosis. After resection these tests were unchanged. Patients with liver related complications and cirrhosis (n = 5) had lower ICG-ER and GEC than patients with cirrhosis and no complications. In the postoperative course all liver function tests in these patients were significantly lower compared to preoperative results. Comparing liver function tests ICG serves best to indicate postoperative liver failure. Liver function tests do not correspond with loss of liver tissue.

Galactose↗
PubMed1995

Reversal of sinus arrest and atrioventricular conduction block in patients with sleep apnea during nasal continuous positive airway pressure.

Sinus arrest and atrioventricular (AV) block have been demonstrated in as much as 30% of patients with sleep apnea (SA). The reversal of heart block after tracheostomy has been shown. Nasal continuous positive airway pressure (nCPAP) now is widely used as the treatment of SA, but little data are available on the effect of nCPAP on heart block in patients with SA. During a 17-mo period 239 patients were found to have SA in an ambulatory study. Heart block was identified in 17 (16 male, one female) of these patients. Standard polysomnography and two-channel long-term ECG before and during nCPAP therapy were performed in order to assess the effect of nCPAP on SA and heart block. Mean age of the 17 patients was 50.7 yr (range, 27 to 78 yr), mean respiratory disturbance index (RDI) was 90/h (SD +/- 36.1) before nCPAP and 6/h (SD +/- 6.2) on the second treatment night. The number of episodes of heart block during sleep decreased significantly (p < 0.001) from 1,575 before therapy to 165 during nCPAP. In 12 patients (70.6%) heart block was totally prevented by nCPAP. In another three patients, there was a 71 to 97% reduction in the number of episodes of heart block on the second treatment night, and in two of them a complete reversal occurred thereafter. Two patients exhibited an increase in block frequency during nCPAP, which was reversed after 4 wk of nCPAP in one but persisted in the other.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[The value of 3D video endoscopy for surgical procedures].

We discuss the problems of spatial perception that arise by the transmission of endoscopic surgery by traditional video systems and analyse the improvements that can be achieved by two- und three-dimensional systems. Starting with a description of the physics of vision and the principles of two- and three-dimensional imaging, we demonstrate the importance of optimal adaptation of technology to the natural perception processes of the observer. In this context we review critically the technology that is presently available. Only stereoscopic video technology with 'shutter glasses' provides the observer with the spatial information that is of such decisive importance for minimally invasive surgery. Finally we discuss new technical developments that further improve three-dimensional vision in endoscopy, such as a 3D video module that is small enough to be used intracorporally.

Computer Peripherals↗
PubMed1995

[Errors and risks in administration of nasal respiratory therapy of obstructive sleep apnea].

Over a period of 1 year we observed in our sleep laboratory in 502 patients with sleep related breathing disorders several side effects of positive airway pressure treatment, furthermore we observed in 5 patients unexpected dangerous complications due to the application of CPAP and BIPAP. We observed mask leakages which lead to insufficient positive airway pressure-therapy and an occurence of short central apnoeas during NREM sleep after arousal or wakefulness periods. Finally we observed in 5 patients during treatment with CPAP and BIPAP an unexpected appearance of long central apnoeas up to 110s and central hypoventilations up to 5 min accompanied by excessive hypoxaemia (SaO2 < 20%) and cardiac arrhythmias. We conclude that in the treatment of obstructive sleep apnoeas we have to expect in 1-2% complications of the positive airway pressure treatment itself. To avoid life endangered complications the first night application should be done only in conventional sleep laboratories.

Equipment Failure↗
PubMed1995

[Parameters for determining the effective treatment pressure in nCPAP therapy of sleep apnea].

We evaluated the accuracy of single parameters from the polysomnography in establishing the effective nCPAP treatment pressure in order to possibly economize pressure adjustment. In four patients (pts) a standard polysomnography was performed. 67 segments of 30-60s in duration, showing different typical types of breathing disturbances or normal breathing were selected. The segments were divided into 5 horizontal parts consisting of only one of the following signals: SaO2, snoring, mask pressure, esophageal pressure (Poes) and respiratory movements (RC + Abd). A second investigator then classified these 335 one lead recordings without knowing the complete segment. The classification based on the complete segment compared to that based on only one parameter gave an identical result in 44.8% (SaO2), 61.2% (Poes), 64.2% (RC + Abd), 80.6% (sonoring) and 82.1% (mask pressure) respectively. 97% of the complete segments were classified identically by both investigators. Each of the studied parameters alone was not adequate in establishing the correct pressure level. SaO2 corresponds least, mask pressure and snoring best to the classification based on all parameters.

Air Pressure↗
PubMed1995

[Machine-assisted detection of individually effective minimal CPAP pressure using the Vitalog HMS 5000 monitor].

UNLABELLED: Continuous positive airway pressure ventilation (CPAP) has been proven to be highly effective in the elimination of sleep-related breathing disorders (SRBD) in the last couple of years. The titration of the effective airway pressure should be carried out under continuous polysomnographic supervision in the sleep laboratory. The CPAP ventilation may result in potential hazards through the positive airway pressure and each patient needs an individually adjusted pressure for therapy. In a prospective study we investigated under polysomnographic supervision the effectivity and the hazards of a machine-controlled CPAP calibration in 22 male patients (pts) (age: 53.6 +/- 8.9 years, BMI: 29.9 +/- 5.0 kg/m2) with obstructive SRBD (RDI: 50.6 +/- 1/h). Automatic CPAP-calibrations were carried out using the Vitalog HMS-5000 monitor and the Respironics BiPAP-STD ventilator. An algorithm determined the cyclical changes of the airway pressure. The following night we controlled the assessed pressure through manual adjustment during conventional polysomnography. RESULTS: The CPAP-levels assessed through the automatic calibrations (8.36 +/- 2.36 cmH2O) showed in 19 pts a good agreement with the CPAP-levels of the control nights (8.15 +/- 2.36 cmH2O), the difference was statistically nonsignificant (p < 0.5). The CPAP-levels of the automatic titrations and the control nights agreed exactly in 12 pts (63%). 3 pts of the 22 failed the automatic CPAP-titration process because of functional or psychical reasons. 14 pts (64% of 22 pts) showed a good functional tolerance to the cyclical changes of the airway pressure. 3 pts were unable to fall asleep under the increasing airway pressure, but after falling asleep at a constant pressure of 2 or 4 cmH2O they could tolerate the automatic pressure titration. A reset of the actual pressure to the baseline was necessary in 13 pts to enable them falling asleep, in 2 pts because of increase of the airway pressure due to movement artifacts, in 2 pts because of central apneas and in one patient because of ventricular extrasystoles. 35 increases of the baseline level (48% of altogether 73 increases) occurred due to clinically irrelevant desaturations. We found a direct hazardous effect of the machine-controlled CPAP-titration (central apneas, secondary alveolar hypoventilation, ventricular extrasystole) in 7 pts with chronic obstructive pulmonary disease and/or cardiovascular disorder. CONCLUSION: The machine-controlled CPAP-titration should be carried out only in a selected group of patients. Nevertheless, despite of the good agreement of the assessed pressure levels with the polysomnographic controls, this method seems to be not suitable for the clinical routine because of its potential hazards and contraindications in high risk patients.

Adult↗
PubMed1995

[Continuous single layer anastomosis as the standard procedure in the gastrointestinal tract].

The continuous suture by single layer technique is suitable for all anastomoses in the gastrointestinal tract. Anastomotic dehiscence rate has been examined and amounts 1.7% for anastomoses in the stomach 0.3% in the small intestine and 2.8% in the colon. In comparison with other techniques the anastomosis is safe and easy to learn. Costs and time of surgery can be reduced significantly.

Anastomosis, Surgical↗
PubMed1995

Transhiatal oesophagectomy compared with transthoracic resection and systematic lymphadenectomy for the treatment of oesophageal cancer.

OBJECTIVE: To compare the results of transhiatal oesophagectomy with those of transthoracic resection with systematic two field en bloc lymphadenectomy in the treatment of carcinoma of the oesophagus. DESIGN: Prospective open (non-random) study. SETTING: University hospital, Germany. SUBJECTS: 87 patients with carcinoma of the oesophagus of whom 46 underwent transhiatal, and 41 transthoracic resection. MAIN OUTCOME MEASURES: Morbidity and short and long term mortality. RESULTS: The type of operation was chosen on clinical grounds, and the groups were comparable except for site and type of tumour, and nodal stage. The hospital mortality was 7/46 (15%) in the transhiatal group and 4/41 (10%) in the transthoracic group. The most common complication was anastomotic leak (23/46, 50%, compared with 10/41, 24%, p = 0.014), followed by major pulmonary complications (16/46, 35%, compared with 12/41, 29%), and cardiac complications (12/46, 26% compared with 11/41, 27%). Median survival was 350 days in the transhiatal group and 378 days in the transthoracic group. The percentage survival after one, two, and three years in the two groups was 48 and 55, 26 and 18, and 21 and 17, respectively. There were no significant differences in short or long term mortality. CONCLUSION: We have been unable to show that the oncologically more radical procedure (transthoracic resection with systematic two field en bloc lymphadenectomy) results in longer survival, but we have shown that it can be done with similar morbidity and short term mortality. Because it is possible to stage the disease exactly with a transthoracic resection, and because published reports from other centres have hinted at improved prognosis after it, we shall continue to do the operation for suitable patients.

Adult↗