Oesophageal seal of the novel supralaryngeal airway device I-Gel in comparison with the laryngeal mask airways Classic and ProSeal using a cadaver model.

BACKGROUND: Supraglottic airway devices are increasingly used in anaesthesia and emergency medicine. This study was designed to investigate the oesophageal seal of the novel supralaryngeal airway device, I-Gel (I-Gel), in comparison with two of the laryngeal mask airways, Classic (cLMA) and ProSeal (pLMA), in a model of elevated oesophageal pressure. METHODS: The three supralaryngeal airway devices were inserted into eight unfixed cadaver models with exposed oesophagi that had been connected to a water column producing both a slow and a fast oesophageal pressure increase. The pressure applied until the loss of oesophageal seal during a slow and fast pressure increase was measured. RESULTS: During the slow increase of pressure, the pLMA withstood an oesophageal pressure up to a median of 58 cm H(2)O, while the cLMA was able to block the oesophagus up to a median of 37 cm H(2)O, and I-Gel already lost its seal at 13 cm H(2)O. One minute after maximum pressure had been applied, the pLMA withstood an oesophageal pressure of 59 cm H(2)O, the cLMA of 46 cm H(2)O, and I-Gel airway of 21 cm H(2)O. A fast release of oesophageal fluid was accomplished through the oesophageal lumen of both the pLMA and I-Gel. CONCLUSIONS: Both the pLMA and cLMA provided a better seal of the oesophagus than the novel I-Gel airway. The pLMA and I-Gel drain off gastrointestinal fluid fast through the oesophageal lumen. Thus, tracheal aspiration may be prevented with their use. Further study is necessary.

Hypertension guidelines and their limitations--the impact of physicians' compliance as evaluated by guideline awareness.

OBJECTIVE: The initial step of an optimal therapeutic strategy for patients with arterial hypertension is the recognition and acceptance of new recommendations by the physicians themselves. This guideline awareness of the physicians has never been evaluated in detail. DESIGN: The awareness of content of current recommendations in hypertension diagnosis, treatment and treatment control was therefore assessed in primary care physicians using a questionnaire. The guidelines of the German Hypertension Society were used as the reference standard. PARTICIPANTS: A total of 24 899 German physicians, including all internists, all cardiologists and 22% of general practitioners were contacted in a nationwide survey. MAIN OUTCOME MEASURES: The number of answers in agreement with the guideline was used as a measure of guideline awareness. Adequate awareness of content of guideline recommendations was defined as the correct answer to five out of eight questions; the correct answers had to include the appropriate definition of hypertension. RESULTS: The analysis was based on 11 547 returned questionnaires (47.1%). An adequate guideline awareness was found in 23.7% of the total study population, especially in 37.1% of cardiologists, in 25.6% of internists and in 18.8% of general practitioners. While the guideline awareness was significantly influenced by the duration of private practice, regional and municipal factors had only minor influence on the results. CONCLUSION: The impact of hypertension guidelines on actual medical knowledge is modest. Thus, the information strategies about current treatment guidelines must be improved and tailored to the needs of physicians in clinical practice to ultimately improve patient care.

[Guideline-adequate knowledge in internists and general practitioners about the diagnosis and treatment of arterial hypertension]. / Leitlinienadäquate Kenntnisse von Internisten und Allgemeinmedizinern am Beispiel der arteriellen Hypertonie.

Only a small proportion of patients with arterial hypertension are adequately treated. Although a possible cause for this fact may be the deficient knowledge of physicians about diagnosis and treatment of arterial hypertension, to date no studies have addressed this important problem in Germany. Therefore, we have reviewed the knowledge of internists and general practitioners about diagnosis and treatment of arterial hypertension using a questionnaire. The guidelines of the German Hypertension Society were used as the reference standard. The questionnaire was sent out in December 1999 to all internists (n = 15,952) and to a random sample of general practitioners (n = 8947) who work as statutory health insurance physicians. A total of 11,547 questionnaires were sent back and could be analysed. Adequate guideline knowledge was assumed if five out of eight questions were correctly answered; the correct answers had to include the correct definition of arterial hypertension (> 140/90 mmHg). The correct definition of arterial hypertension was known by 4103/11,547 participants (36%). An adequate guideline knowledge was found in 18.8% of the general practitioners and in 26.6% of the internists. There were no relevant regional differences. The level of awareness about diagnosis and treatment of arterial hypertension is insufficient among internists and general practitioners. This insufficient knowledge may in part explain the inadequate care for patients with arterial hypertension. Thus, the implementation and evaluation of new information and training strategies are mandatory to improve the care for patients with arterial hypertension.

IFCC recommendation on reporting results for blood glucose.

In human beings, glucose is distributed like water between erythrocytes and plasma. The molality of glucose (amount of glucose per unit water mass) is the same throughout the sample. Different water concentrations in calibrator, plasma, and erythrocyte fluid can explain some differences that are dependent on sample type, methods requiring sample dilution, and direct reading biosensors detecting molality. Different devices for the measurement of glucose detect and report fundamentally different analytical quantities. The differences exceed the maximum allowable error of glucose determinations for diagnosing and monitoring diabetes mellitus, and they complicate the treatment. The goal of the International Federation of Clinical Chemistry, Scientific Division, Working Group on Selective Electrodes (IFCC-SD WGSE) is to reach a global consensus on reporting results. The document recommends harmonizing to the concentration of glucose in plasma (with the unit mmol/l), irrespective of sample type or technology. A constant factor of 1.11 will convert measured concentration in whole blood to the equivalent concentration in plasma.

Relationship between flow rate and NO production in postnatal mesenteric arteries.

We studied mesenteric arterial arcades from 3- and 35-day-old swine to determine the relationship between perfusate flow rate and release of nitric oxide (NO) into mesenteric effluent. Mesenteric arterial arcades were perfused under controlled-flow conditions with a peristaltic pump using warm oxygenated Krebs buffer. Basal rates of NO production were 43.6 +/- 4.2 vs. 12.1 +/- 2.5 nmol/min in 3- vs. 35-day-old mesentery during perfusion at in vivo flow rates (9 vs. 20 ml/min, respectively). Rate of NO production was directly related to flow rate over a wide range of flows (5-40 ml/min) in 3- but not 35-day-old mesentery. Both age groups demonstrated a brisk, albeit brief, increase in NO production in response to infusion of NO-dependent vasodilator substance P (10(-8) M/min). Tyrosine kinase inhibitor herbimycin A and L-arginine analog L-NMMA significantly attenuated flow-induced increase in NO production, and phosphatase inhibitor phenylarsine oxide increased magnitude of flow-induced increase in NO production in 3-day-olds. Removal of extracellular Ca(2+) and depletion of intracellular Ca(2+) stores (Ca(2+)-free Krebs with EGTA plus thapsigargin) had no effect on NO production in either group. Thus, basal rate of NO production is greater in mesenteric arterial arcades from 3- than from 35-day old swine, a direct relationship between flow rate and NO production rate is present in mesentery from 3- but not 35-day-olds, and phosphorylation events are necessary for this interaction to occur.

Patients with dilated cardiomyopathy and less than 20% ejection fraction increase exercise capacity and have less severe arrhythmia after controlled exercise training.

The results of this pilot study suggest that patients with a diminished ejection fraction as low as 16% can safely perform an exercise program. A significant improvement in peak VO2 and maximal work rate was achieved. Moreover, this study suggests that exercise training might diminish the severity of asymptomatic ventricular arrhythmia; however a larger controlled study is needed to confirm these findings.

[The place of thoracic plain film in the assessment of left heart insufficiency]. / Zum Stellenwert der Thoraxübersichtsaufnahme bei der Beurteilung der chronischen Linksherzinsuffizienz.

The chest radiographs of 24 patients with chronic left heart failure (mean duration of cardiac disease 4.3 years) were compared with the haemodynamic findings. Before the initiation of intensive medical treatment haemodynamic parameters were measured invasively and followed up for a period of up to 16 months. The heart size and roentgenographic patterns of pulmonary congestion showed a weak negative correlation with both the ejection fraction and the cardiac index. During therapy changes of cardiopulmonary haemodynamics did not correlate with alterations of the radiographic findings. Therefore chest radiographs are not useful in the assessment of the therapeutic success in long-existing left heart failure; nevertheless, they are indicated to identify secondary pulmonary disease.

Cardiopulmonary exercise testing (CPX) and transthoracic bioimpedance measurements: new tools for an "old disease" (congestive heart failure).

The purpose of the study was to examine the cardiovascular and cardiopulmonary exercise capacity in patients with symptomatic congestive heart failure more exactly than with conventional investigations, using the simultaneous non-invasive determination of the gas exchange parameters (ergospirometry, CPX) and of the hemodynamic (transthoracic bioimpedance). The reproducibility of the data were measured with each method with repeated tests under the same conditions in healthy subjects and patients with myocardial failure. Therefore we tested 15 patients with documented congestive heart failure repeatedly on a bicycle (semi-supine, +15 watts/min, symptom-limited). The ergospirometric (VO2, VCO2, RER = VCO2/VO2, max. VO2, VO2AT, VE, RR) and the bioimpedance-parameters (CI, SVI, HR) were measured simultaneously during rest and exercise. According to Wasserman et al. we used the VO2AT and the max. VO2 to assign the patients to the different Weber classes: Weber A: greater than 20 ml/min/kg max. VO2, greater than 14 ml/min/kg VO2AT; Weber B: 16 to 20 ml/min/kg max. VO2, 11 to 14 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. ml/min/kg VO2AT; Weber C: 10 to 16 ml/min/kg max. VO2, 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. VO2, 4 to 8 ml/min/kg VO2AT: Weber E: less than 6 ml/min/kg max. VO2, less than 4 ml/min/kg VO2AT. The V-slope-method according to Beaver et al. allowed for the determination of the anaerobic threshold in 13/15 patients. 2/15 patients didn't reach the anaerobic threshold. Oscillations of the gas exchange parameters due to Cheyne-Stokes-breathing were found in 9/15 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a twenty-four-hour milrinone infusion in patients with severe heart failure and cardiogenic shock as a function of the hemodynamic initial condition.

The systemic and pulmonary arterial hemodynamics of 40 patients with severe congestive heart failure were determined during a 24-hour infusion of milrinone (0.5 micrograms/kg/min) after a loading dose of 50 micrograms/kg. A subgroup (n = 18) with severe cardiac pump dysfunction and three patients in cardiogenic shock were analyzed separately; their hemodynamic response was compared with that of the total group (n = 40). After 15 minutes of intravenous therapy with milrinone, the total group (n = 40) showed an increase of 65% in cardiac index; in the subgroup (n = 18) cardiac index increased by 94% after 15 minutes and by 106% after 30 minutes. Likewise, pulmonary capillary wedge pressure decreased after 30 minutes in both the total group (n = 40) and the subgroup (n = 18). The heart rate showed an overall tendency to decrease. The systolic blood pressure tended upward and remained statistically unchanged in the total group, whereas in the subgroup in which pressure was initially low, there was an increase in the systolic pressure after 1 hour and a further increase after 24 hours. Mean arterial pressure also rose in this subgroup. The early improvement in all measured hemodynamic parameters was sustained throughout the 24-hour infusion period. Development of tolerance was not observed, nor were any clinically symptomatic side effects or symptomatic arrhythmias. Thus intravenous milrinone is a safe medication for the rapid and prolonged improvement in hemodynamics, specifically in patients with severely restricted cardiac pumping function.

Phosphodiesterase III inhibition or adrenoreceptor stimulation: milrinone as an alternative to dobutamine in the treatment of severe heart failure.

High levels of endogenous plasma catecholamines in patients with severe congestive heart failure induce a down-regulation of the myocardial beta-adrenoreceptors and thus cause adrenoreceptor agonists, such as dobutamine, to be less effective in the treatment of these patients. Phosphodiesterase III inhibitors work independent of adrenoreceptor activity and plasma catecholamine levels; thus these agents are likely to be more effective in the treatment of severe heart failure. The present study compares both the initial and late hemodynamic effects of dobutamine and milrinone during sequentially administered 24-hour infusions. Twenty patients with severe heart failure (New York Heart Association class III, n = 4; New York Heart Association class IV, n = 16) were investigated. Dobutamine could be administered at the prescribed maximum dose of 15 micrograms/kg/min for 24 hours in only 15 of 20 patients. In three patients the dose was reduced or dobutamine infusion completely stopped because of a drug-related increase in heart rate greater than 140 beats/min. Another 2 of 20 patients showed no hemodynamic improvement over 3 hours at the maximum dose of 15 micrograms/kg/min. Dobutamine administration was also discontinued in these patients on account of the existing unfavorable hemodynamic condition, and therapy with intravenous milrinone was started. All 20 patients responded to milrinone without side effects, although comparison of the hemodynamic effects during a 24-hour infusion was possible in only 15 patients. The 15 patients studied over both observation periods experienced an increase in heart rate from 88.8 to 105.6 beats/min (+ 1 hour; p less than or equal to 0.001) when receiving dobutamine but had no increase with milrinone. Stroke volume increased during dobutamine infusion from 19.3 to 28.9 ml/m2 (+49.6%) after 1 hour and then fell continuously to 25.2 ml/m2 after 12 hours; during milrinone therapy, stroke volume increased from 18.8 to 31.2 ml/m2 (+66%; p less than or equal to 0.001) and remained at this level until the end of the infusion (30.2 ml/m2). Pulmonary capillary wedge pressure (PCWP) decreased (p less than or equal to 0.001) immediately during milrinone therapy from 26.5 to 16.2 mm Hg after 30 minutes and stabilized at 20.1 mm Hg after 24 hours. During dobutamine infusion PCWP showed a delayed decrease from 27.8 to 19.0 mm Hg after 6 hours and subsequently rose to 22.7 mm Hg after 24 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

[The effect of hemodynamic changes in 24-hour milrinone infusion on sympathetic activity and the renin-angiotensin-aldosterone system in patients with severe heart failure]. / Auswirkung der hämodynamischen Veränderungen unter 24stündiger Milrinon-Infusion auf die sympathische Aktivität und das Renin-Angiotensin-Aldosteron-System bei Patienten mit schwerer Herzinsuffizienz.

The hemodynamics of 18 patients (subgroup A) with severe heart failure (baseline Cl less than or equal to 1.55 l.min-1.m-2), including three patients with cardiogenic shock, and another 22 patients (subgroup B) with moderate heart failure (baseline Cl from 1.55 to 2.5 l.min-1.m-2) were investigated during a 24 h milrinone infusion, combined with investigation of the response of the sympathetic tone (plasma catecholamine levels) and the renin-angiotensin-aldosterone system to the hemodynamic improvement in both subgroups. Cl increased (p less than or equal to 0.001) to 162.7% after 5 min and further to 206.4% of baseline after 30 min of milrinone therapy in subgroup A, and in B to 139.3% and further to 146.4% after 15 min. PCWP decreased (p less than or equal to 0.001) to 83.8% and further to 65.5% of baseline after 30 min in subgroup A, and to 58.4% in subgroup B. Heart rate decreased (p less than or equal to 0.05) from 99.4 to 94.7 bpm in A and showed a decreasing tendency in B. MAP rose in A from 75.5 to 79.4 after 1 h and further to 83.3 mm Hg (p less than or equal to 0.01) after 24 h; in subgroup B, MAP did not change. Plasma noradrenaline level decreased (p less than or equal to 0.001) in A from 1419.5 (B: 782.9) to 838.2 (B: 529.6) after 1 h and further to 655.1 (B: 467.9) pg/ml after 24 h. Plasma renin decreased (p less than or equal to 0.01) in A from 1047.6 (B: 460.2) to 597.4 (B: 222.5) and further to 392.6 (B: 191.7) microU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamics with dobutamine and milrinone in patients with severe heart failure in an intra-individual comparison]. / Hämodynamik unter Dobutamin und Milrinon bei Patienten mit schwerer Herzinsuffizienz im intraindividuellen Vergleich.

Hemodynamics during 24-h dobutamine (dob) and subsequent 24-h milrinone (mil) infusion were studied in 20 patients (pts) with severe heart failure (NYHA III: 4 pts, NYHA IV: 16 pts). Three of 20 patients showed a heart-rate increase to 140 bpm and more during dob; five patients were non-responders to dob. Heart rate rose (p less than or equal to 0.001) during dob from 88.8 to 105.6 bpm (+1 hr) and then decreased to 93.0 bpm after 24 h; stroke volume index increased (p less than or equal to 0.001) from 19.3 to 28.9 ml.m-2 (+49.6%) after 1 h and then decreased to 25.2 ml.m-2 after 12 h as did heart rate. During mil heart rate did not change; stroke volume index increased from 18.8 to 31.2 (+66.0%, p less than or equal to 0.001) after 1 h and showed no development of tolerance during the rest of the infusion period. PCWP decreased (p less than or equal to 0.001) during mil from 26.5 to 16.2 mm Hg after 30 min, tending upward again to 20.1 mm Hg after 24 h; during dob the decrease (p less than or equal to 0.01) of PCWP from 27.8 to 19.0 mm Hg after 6 h was delayed, also tending upward during the rest of the infusion period to 22.7 mm Hg after 24 h. There was no sustained decrease of PVR during dob, but after the start of mil infusion PVR decreased (p less than or equal to 0.001) from 312.7 to 172.1 dynes/s/cm-5 (+15 min), remaining on this level during the rest of mil infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamics and differentiated CO transfer following fulminant lung embolism and pulmonary artery embolectomy and following recurrent lung embolism]. / Hämodynamik und differenzierter CO-Transfer nach fulminanter Lungenembolie und Pulmonalisembolektomie sowie nach rezidivierenden Lungenembolien.

Pulmonary embolectomy as an emergent surgical treatment after massive pulmonary embolism often is necessary in cardiogenic shock (CS) and even without previous diagnostic. If complete dissolution of the thromboembolus is possible or spreading of microemboli may occur is unknown. Therefore we studied 21 patients surgically treated by embolectomy, ten of these with consecutive cardiogenic shock (CS) and twelve patients after repetitive microembolism and cava-blocking. Besides lung-functional parameters for special CO-diffusion capacity (DLCO), differentiated in membrane (DM) and vascular (VC) component (Roughton and Forster), we measured mean pulmonary artery pressure (PAP) at rest and at exercise. Patients after repetitive embolism showed considerably more diminution of DLCO (-31%) than those after single massive embolic event (-15%) even concomitant by CS (-10%). Repetitive microembolism lowered VC by 21%. Slight decrease of DM was found after CS. Mean pulmonary artery pressure was elevated at rest (26 mm Hg) and exercise (33 mm Hg) after repetitive microembolism and normal after massive embolism or CS. Pulmonary embolectomy may prevent disturbances of DLCO or PAP even after CS. Damage of vascular integrity (VC) was found after microembolism. Pulmonary embolectomy seems to remove total embolic material and therefore seems to be optimal.

[Microbiological aspects of nosocomial risks of suction bottles]. / Aspects microbiologiques des risques nosocomiaux des flacons d'aspiration.

The suction and collection of more or less contaminated biological fluids or regurgitated matter in reusable glass bottles may be responsible for nosocomial infections. Based on a study conducted in 49 cases, the authors try to demonstrate the microbiological risks in the operating theatre of changing and transport of these bottles and the risks for the environment and the hospital staff in the cleaning of these bottles. The connection to the vacuum system was found to be contaminated in 26.1% of cases, the environment of the waste evacuation and cleaning zone was contaminated in 59.2% of cases and, in 28.6% of cases, the microorganism detected was identical to that in the bottle. All of these factors suggest that a disposable system, although apparently more expensive, ensures a greater degree of safety, avoiding the problems related to transport emptying and elimination of these bottles.