Berechnung von CO2-Verlaufswerten aus Pulsoximetrien von Patienten unter nichtinvasiver nächtlicher Beatmung

Die respiratorische Insuffizienz lässt sich in eine hypoxämische und eine hyperkapnische respiratorische Insuffizienz differenzieren. Bei beiden Formen kann ein akuter und ein chronischer Verlauf unterschieden werden. Die häufigsten Ursachen der chronischen hyperkapnischen/ventilatorischen Insuffizienz sind Erkrankungen, bei denen es zur Erschöpfung der inspiratorischen Atemmuskulatur kommt. Hierzu zählen neuromuskuläre Erkrankungen, Kyphoskoliose, das Obesitas-Hypoventilationssyndrom und die chronisch obstruktive Lungenerkrankung. Mit fortschreitender Krankheit treten sowohl nachts als auch tagsüber Hyperkapnien auf. Den Patienten fällt dies vor allem durch das Auftreten einer Belastungsdyspnoe auf. Die Gefahr der Erkrankung besteht jedoch in einer Verschlechterung der Erkrankung mit zunehmender Erhöhung der pCO2-Werte und einer CO2-Narkose. Um dies zu verhindern, wird neben der invasiven auch die nichtinvasive Beatmung eingesetzt. Die Indikation für die nichtinvasive Beatmung wird dabei vor allem in Abhängigkeit vom Grad der Hyperkapnie, das heißt vom gemessenen pCO2-Wert, gestellt. Der pCO2 kann mithilfe verschiedener Methoden bestimmt werden. Während die end-tidale Messung in der Schlafmedizin keine Rolle spielt, werden die transkutane Messung sowie die Bestimmung aus arteriellem oder kapillärem Blut mittels einer Blutgasanalyse standardmäßig eingesetzt. Zum Monitoring und zur optimalen Anpassung der nichtinvasiven Beatmung ist allerdings eine kontinuierliche pCO2-Messung erforderlich. Das einzige dafür aktuell verfügbare Verfahren ist die transkutane pCO2-Messung. Entsprechend mehreren Studien liefert sie klinisch akzeptable Werte im Vergleich zur Blutgasanalyse und kann deshalb als Goldstandard der pCO2-Verlaufsmessung angesehen werden. Der Unterhalt der transkutanen Messgeräte ist jedoch sehr kostspielig, sodass es das Ziel dieser Studie war ein kostengünstigeres Alternativverfahren zu validieren. Diese Studie ist die erste, die die pCO2-Verlaufswerte aus Pulsoximetrien von Patienten unter nichtinvasiver nächtlicher Beatmung nach Ein-Punkt-Kalibrierung mithilfe einer patentierten Formel berechnet. Dafür wurden 20 Patienten unter nichtinvasiver Beatmung, von denen 10 Patienten zusätzlich Sauerstoff erhielten, rekrutiert. Es erfolgte eine nächtliche transkutane pCO2-Messung mit TOSCA 500-Messgeräten sowie die Abnahme von mindestens einer kapillären Blutgasanalyse für die Ein-Punkt-Kalibrierung. Im Anschluss an die Messung wurde der nächtliche pCO2-Verlauf aus den erhobenen Daten für jeden Patienten mit der Grundformel und einer SpO2-korrigierten Formel berechnet und mit den transkutanen Messwerten verglichen. Ziel der SpO2-Korrektur war es, die pCO2-Anstiege während nächtlicher Sauerstoff-Entsättigungen oder Leckagen besser abzubilden. Die graphische Darstellung der berechneten und transkutan gemessenen pCO2-Werte ließ einen ähnlichen Kurvenverlauf erkennen, der durch die SpO2-Korrektur weiter verbessert werden konnte. Die mittlere Abweichung der beiden Verfahren lag mit Ausnahme von vier Patienten sowohl bei der Einzel- als auch bei der Gruppenauswertung unter ± 4 mmHg. Die Regressionsanalyse konnte für die Patienten mit nichtinvasiver Beatmung ohne O2-Therapie, diejenigen mit nichtinvasiver Beatmung und O2-Therapie und auch für die Patienten mit starken nächtlichen pCO2-Schwankungen ≥ 10 mmHg einen stark positiven und statistisch signifikanten Zusammenhang nachweisen. Die Korrelation nahm mithilfe der SpO2-Korrektur im Vergleich zur Grundformel noch zu. Die Bland-Altman-Analysen ergaben einen Bias für die verschiedenen Gruppen von -0,84 mmHg bis 0,36 mmHg. Die limits of agreement erstreckten sich von maximal -8,16 mmHg bis 8,33 mmHg. Zusammenfassend konnte erstmals gezeigt werden, dass sich CO2-Verlaufswerte aus Pulsoximetrien von Patienten unter nichtinvasiver nächtlicher Beatmung zuverlässig und klinisch akzeptabel berechnen lassen. Um das übergeordnete Ziel, die Entwicklung eines Gerätes, das die pCO2-Verlaufswerte direkt nach einmaliger blutiger BGA-Kalibrierung aus der Pulsoximetrie berechnen kann, zu erreichen, sind jedoch Untersuchungen mit einer größeren Stichprobe notwendig. Dabei sollte die Faktorberechnung der SpO2-Korrektur weiter angepasst und der Hb-Wert der Patienten als weitere Komponente der Berechnungsformel geprüft werden. Zudem gilt es den standardisierten Einsatz des Pulsfrequenzmittelwertes zur Kalibrierung und eine automatisierte Einrechnung der Phasenverschiebung zu untersuchen

Catecholamine activity and infectious disease episodes

Abstract: The profile of 3-hydroxy-4-methoxy methoxy acid (VMA) excretion was studied in relation to reported acute infectious disease episodes. Daily VMA excretion levels and symptom reports were analyzed for a group of 47 volunteers over a four-week period. Results showed a tendency for elevated VMA levels to occur with greater frequency within three days prior to the onset of symptoms. These findings are interpreted as suggesting that elevated levels of catecholamine activity may increase susceptibility to disease by interfering with the immune response, and in the presence of an agent lead to an infectious disease episode

An epidemiologic study of tennis elbow: Incidence, recurrence, and effectiveness of prevention strategies

An epidemiologic study of the incidence and recurrence of tennis elbow among over 500 tennis players (278 men, 254 women; age range, 20 to 50 years) indicated that age and amount of playing time per day were contributing factors to the injury. Both incidence and recurrence rates increased with age. An interactive effect of playing time and age was observed with increased playing time associated with higher incidence at younger ages. Larger grip size was also associated with higher incidence in the older group. These findings were interpreted as being consistent with the hypothesis that tennis elbow is a degenerative disease, the onset of which is hastened by overuse of the arm and elbow. Changes in stroke technique and types of racket were successful in preventing recurrence. Least successful was the forearm brace

Body Fat Distribution and Male/Female Differences in Lipids and Lipoproteins

The role of body fat distribution, as assessed by the ratio of waist-to-hip circumferences (WHR), in statistically explaining differences in levels of lipoproteins between men and women was studied using data collected in 1985-1986 from employed adults (mean age, 40 years). As compared with the 415 women, the 709 men had higher mean levels of triglycerides (+38 mg/dl) and apolipoprotein B (+11 mg/dl) as well as lower mean levels of high density lipoprotein (HDL) cholesterol (-15 mg/dl) and apolipoprotein A-I (-19 mg/dl). Additionally, men were more overweight, consumed more alcohol, and exercised more frequently than women but were less likely to smoke cigarettes. Controlling for these characteristics, however, did not alter the differences in lipoprotein levels between men and women. In contrast, adjustment for WHR (which was greater among men) reduced the sex differences in levels of apolipoprotein B (by 98%), triglycerides (by 94%), HDL cholesterol (by 33%), and apolipoprotein A-I (by 21%). Similar results were obtained using analysis of covariance, stratification, or matching; at comparable levels of WHR, differences in lipid and lipoprotein levels between men and women were greatly reduced. Although these results are based on cross-sectional analyses of employed adults and need to be replicated in other populations, the findings emphasize the relative importance of body fat distribution. Whereas generalized obesity and body fat distribution are associated with lipid levels, fat distribution (or a characteristic influencing fat patterning) can be an important determinant of sex differences in levels of triglycerides, HDL cholesterol, and apolipoproteins B and A-I

Associations of Aerobic Exercise and Alcohol Consumption With Systolic Blood Pressure in Employed Males

Patterns of alcohol consumption and physical activity were analysed in relation to blood pressure in a group of 522 employed males. Alcohol intake, as well as age and the body mass index, were directly related to systolic blood pressure (SBP) while aerobic exercise was inversely related. Men who exercised occasionally or not at all had a mean (&#x00B1 s.d.) SSP of 120.3 &#x00B1 14.3, whereas men who took frequent exercise had a mean SSP of 117.4 &#x00B1 12.7 (P < 0.02). Among light and moderate drinkers (&#x2264 7 ounces/week), increased frequency of exercise was associated with a lower SBP (b = -0.149, P = 0.05); but we observed no effect among heavy drinkers (b = -0.036, P is NS). These findings suggest that the contribution of aerobic exercise towards lowering SSP may be mitigated by heavier use of alcohol

Relation of triglyceride levels to coronary artery disease: The Milwaukee Cardiovascular Data Registry.

Although levels of triglycerides have consistently shown a strong association with cardiovascular disease In both case-control and cohort studies, it remains controversial whether this relation exists Independently of levels of cholesterol and other risk factors. The association of arteriographically documented coronary artery disease with plasma levels of triglycerides, total cholesterol, and high density lipoprotein (HDL) cholesterol was therefore examined in 5,216 white adults (81% were male) referred to two Milwaukee hospitals between 1972 and 1988. Elevated levels of triglycerides were related to the extent of coronary artery disease (estimated using the total number and severity of stenoses). In both sexes, this association existed independently of total cholesterol, age, obesity, hypertension, smoking, and alcohol consumption. In addition, the association between triglycerides and coronary artery occlusion was strongest at total cholesterol levels &#x2264 250 mg/dl. However, both +stratified and regression analyses Indicated there was no residual association between triglyceride levels and occlusion after controlling for HDL cholesterol. (Levels of HDL cholesterol and triglycerides showed a moderate Inverse association: r = -0.39 to -0.51.) These results indicate that the association between coronary artery occlusion and levels of triglycerides is indirect, and that the disparate findings of earner studies may have resulted from not controlling for HDL cholesterol

Threshold Effects of Dietary Calcium on Blood Pressure

The relationships of calcium and dietary sodium, potassium and alcohol to blood pressures were studied at three different levels of dietary calcium intake by adults in the Health and Nutrition Examination Survey (HANES) I sample. At low calcium intakes (P < 0.01). At higher calcium intakes alcohol, but not Na:K, was significantly related to blood pressures. Neither sodium nor potassium was separately related to blood pressure when the Na:K ratio was included in the regression model. The threshold effect of calcium was observed in all race-gender groups. These results indicate: (i) the Na:K is a more important correlate of blood pressure than either nutrient alone; and (2) a low calcium intake is necessary for the Na:K ratio to maximally affect blood pressure

Black/White Differences in Risk Factors for Arteriographically Documented Coronary Artery Disease in Men

Although the leading cause of death among black men in the United States is coronary artery disease (CAD), risk factors have not been well documented in black populations. Therefore, possible racial differences in the relation of several characteristics to the extent of CAD were assessed in 4,722 white and 169 black men who underwent arteriography. Associations between an occlusion score (ranging from 0 to 300), reflecting the severity of CAD, and levels of total and high-density lipoprotein (HDL) cholesterol, triglycerides, cigarette smoking, alcohol intake, relative weight, systemic hypertension and diabetes mellitus were examined. Most risk factors were significantly related to the extent of CAD in both races, but lipid levels showed stronger associations with CAD among blacks: correlations between CAD and total cholesterol were 0.16 (whites) vs 0.29 (blacks) and associations with HDL cholesterol were -0.22 (whites) vs -0.49 (blacks). In addition, at adverse levels of certain risk factors, blacks had more extensive CAD than did whites: mean occlusion scores were 148 (whites) and 238 (blacks) at HDL cholesterol levels <30 mg/dl. As assessed by multiple linear regression, however, only triglyceride levels were differentially related to CAD between whites (&#x03B2 = 0) and blacks (&#x03B2 = 0.47), p <0.01 for racial contrast. These results document the importance of risk factors in black men and indicate black/white differences in the relation of triglycerides to CAD

Effects of Drinking Patterns on the Relationship between Alcohol and Coronary Occlusion

Previous reports have described an inverse relationship between alcohol consumption and the prevalence of myocardial infarction or the extent of coronary artery occlusion. The study reported here explored the relationship between patterns of alcohol intake and coronary occlusion in 526 male patients who have had coronary arteriography. Patients were characterized as regular drinkers, occasional drinkers and non-drinkers. Regular drinkers were further characterized as drinking relatively consistent amounts or variable amounts. The inverse correlation between amounts of alcohol consumed and coronary occlusion found in previous studies was reaffirmed. It was also observed that the pattern of alcohol intake was related to the degree of occlusion. Higher levels of occlusion were found among non-drinkers, occasional drinkers, and regular drinkers with patterns of variable intake, while significantly lower levels of occlusion were observed for regular drinkers who drank relatively consistent amounts (P = 0.014). Furthermore, while occlusion scores were inversely correlated with amounts consumed by regular drinkers with consistent intake (P =0.019), drinkers with variable drinking patterns had higher occlusion scores regardless of amounts consumed. Analyses of serum lipids according to drinking patterns showed a significant association between the total/HDL cholesterol ratio and drinking patterns. These findings suggest that whatever attenuating effect alcohol consumption might exert on coronary occlusion, it appears to be reversed by a variable or sporadic pattern of alcohol intake

Risk factors and the anatomic distribution of coronary artery disease

Differences in the importance of risk factors according to the anatomic location of coronary artery disease (CAD) were assessed in 4722 men and 1069 women who underwent arteriography. Examined characteristics included total and high-density lipoprotein (HDL)-cholesterol, triglycerides, obesity, smoking. Alcohol consumption, diabetes, and hypertension. Of these risk factors, the ratio of total to HDL-cholesterol showed the highest correlation with the overall severity of CAD (r = 0.24, men; r = 0.38, women); in contrast, its relation to left main (LM) disease was much lower (r =0.10, men; r = 0.08 women) than were correlations with stenotic disease in the left anterior descending, circumflex, and right coronary arteries. Other risk factors also showed weaker associations with LM disease than with stenoses in other vessels, and none was related to increased LM disease after controlling for disease in other vessels. For example, as compared with men who had no significant CAD, those with 1-, 2-, and 3-vessel disease had mean increases in total cholesterol of 12, 18, and 19 mg/dl, respectively. In contrast, after adjusting for disease in other vessels, LM disease (present in 293 men) was associated with only a 4 mg/dl increase in mean cholesterol levels (P = 0.20). These results indicate that the relation of risk factors to CAD differs according to the location of the stenotic disease, and that LM disease is poorly predicted by the standard risk factors