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Biomedical subjects

G Riccardi

Publications and source records attributed to G Riccardi.

At least 91 records · Page 5Linked to original sources
PubMed1996

Long-term effects of fish oil on insulin resistance and plasma lipoproteins in NIDDM patients with hypertriglyceridemia.

OBJECTIVE: The aim of this study was to evaluate the long-term (6-month) effects of moderate fish oil supplementation on insulin sensitivity and plasma lipoproteins in NIDDM patients with hypertriglyceridemia. RESEARCH DESIGN AND METHODS: The study has been performed according to a randomized double-blind placebo-controlled design with a parallel group sequence. After a washout period of 4 weeks and a run-in period of 3 weeks, 16 NIDDM patients with hypertriglyceridemia (triglyceride [TG], 2.25-5.65 mmol/l) were randomly assigned to either fish oil (2.7 g/day eicosapentaenoic plus docosahexaenoic acid for 2 months, then 1.7 g/day for 4 more months) (n = 8) or placebo (n = 8). Diet and hypoglycemic drugs remained unchanged throughout the whole experiment. At baseline and after 6 months, insulin sensitivity was measured by euglycemic hyperinsulinemic clamp (insulin infused, 2.0 mIU.kg-1 body wt.min-1). At the same time, blood glucose control, fasting and postprandial serum insulin and nonesterified fatty acid (NEFA) concentrations, and fasting plasma lipoprotein concentrations were evaluated. RESULTS: In the group treated with fish oil compared with the baseline, there was: 1) a significant reduction in both plasma TG (2.92 +/- 0.23 vs. 3.85 +/- 0.32 [mean +/- SE] mmol/l, P < 0.001) and VLDL-TG (2.35 +/- 0.24 vs. 4.25 +/- 0.66 mmol/l, P < 0.01), without significant changes in blood glucose control; 2) a significant reduction in fasting NEFA concentrations (572 +/- 100 vs. 825 +/- 131 mumol/l, P < 0.01); and 3) a significant enrichment in long-chain omega-3 fatty acids of erythrocyte membrane phospholipids. In the placebo group, there were no changes in any of the variables analyzed. The insulin-mediated glucose uptake was unchanged in both groups (fish oil, 4.04 +/- 0.82 mg.kg-1.min-1 at baseline and 3.96 +/- 0.50 mg.kg-1.min-1 at 6 months; placebo, 3.51 +/- 0.62 mg.kg-1.min-1 at baseline and 4.09 +/- 0.49 mg.kg-1.min-1 at 6 months). CONCLUSIONS: In NIDDM patients with hypertriglyceridemia, moderate amounts of fish oil induce a long-term significant reduction in plasma triglycerides, VLDL triglycerides, and NEFA and a significant enrichment in the erythrocyte phospholipid content of long-chain omega-3 fatty acids, without deteriorating blood glucose control. However, this amount of omega-3 fatty acids was unable to improve insulin sensitivity in this group of patients.

Blood Glucose↗
PubMed1996

Does a high-carbohydrate diet have different effects in NIDDM patients treated with diet alone or hypoglycemic drugs?

OBJECTIVE: To compare the effects of a nigh-carbohydrate diet on blood glucose and plasma lipids in NIDDM patients with either mild or severe glucose intolerance. RESEARCH DESIGN AND METHODS: A crossover design with a 15-day intervention diet was used. Eighteen patients were separated into two groups on the basis of hypoglycemic treatment (diet, n = 9, or diet plus glibenclamide, n = 9) and were assigned to a 15-day treatment with a high-carbohydrate/low-fiber diet containing 60% energy from carbohydrate and 20% from fat or a low-carbohydrate/low-fiber diet with 40% energy from carbohydrate and 40% from fat and then crossed over to the other diet for 15 more days. RESULTS: The high-carbohydrate diet produced a significant increase in postprandial blood glucose in patients on glibenclamide (13.6 +/- 1.4 vs. 11.0 +/- 1.8 mmol/l, P < 0.002, while no difference was recorded in the group on diet alone (9.7 +/- vs. 8.9 +/- 0.6 mmol/l). Postprandial insulin levels were significantly higher after the high-carbohydrate diet in the group on diet along (248 +/- 32 vs. 192 +/- 28 pmol/l, P < 0.01), while no significant differences were observed in the other group (226 +/- 19 vs. 202 +/- 24 pmol/l) The high-carbohydrate diet also induced a significant increase in fasting plasma triglyceride concentrations in both groups (1.36 +/- 0.2 vs. 1.12 +/- 0.2 mmol/l, P < 0.05 and 1.4 +/- 0.3 vs. 1.1 +/- 0.1 mmol/l, P < 0.05). No differences were observed in fasting plasma cholesterol and HDL. CONCLUSIONS: The effects of the high-carbohydrate diet on blood glucose control in NIDDM patients differ according to severity of glucose intolerance.

Biomarkers↗
PubMed1995

Cloning, sequencing and expression of the ilvBNC gene cluster from Streptomyces avermitilis.

The metabolism of the branched-chain amino acids (BCAA) isoleucine, leucine and valine is correlated to the production of polyketide antibiotics in many streptomycetes. Despite its significance, this biosynthetic pathway is poorly understood in Streptomyces. In order to develop a better understanding of Streptomyces BCCA biosynthesis, two genes, ilvBN and ilvC, encoding acetohydroxy acid synthase (AHS) and acetohydroxy acid isomeroreductase (IR), respectively, were cloned from Streptomyces avermitilis, a strain producing avermectins, potent antiparasitic compounds. The genes were isolated by applying a combination of PCR and genomic library screening. The deduced amino-acid sequences revealed significant homology to the AHS and IR proteins from other bacterial species. The ilvBN gene, expressed in Escherichia coli (Ec) by using the expression vector pGEX-4T-1, complemented the ilv- mutation of Ec PS1283. Ec transformants produced high levels of AHS, whose activity was feedback inhibited by valine.

Acetolactate Synthase↗
PubMed1995

Early abnormalities of cardiac function in non-insulin-dependent diabetes mellitus and impaired glucose tolerance.

The aim of this study was to evaluate the role of diabetes and minor abnormalities of glucose homeostasis, such as impaired glucose tolerance, as determinants of cardiac function and structure in a working population. We studied a population-based sample of 64 telephone company employees (both sexes, mean age 58 years): 25 with normoglycemia, 15 with impaired glucose tolerance, and 24 with non-insulin-dependent diabetes mellitus (NIDDM) diagnosed by oral glucose tolerance test according to the recommendations of the World Health Organization. Subjects with myocardial ischemia were excluded. Left ventricular end-systolic dimension, indexed to body surface area, was greater in those with NIDDM (p < 0.05) and in those with impaired glucose tolerance (p < 0.05) with respect to normoglycemic persons. The ratio of the peak early diastolic velocity wave to the late diastolic wave was lower in those with NIDDM (p < 0.05) and in those with impaired glucose tolerance (p < 0.05) than in participants with normoglycemia. Body mass index and blood pressure were similar in the 3 groups. These results clearly indicate that early abnormalities of cardiac structure and function are observed not only in patients with NIDDM, but also in those with impaired glucose tolerance, independent of the confounding role of myocardial ischemia, body weight, and blood pressure.

Adult↗
PubMed1995

Very low density lipoprotein subfraction abnormalities in IDDM patients: any effect of blood glucose control?

Normolipidaemic insulin-dependent diabetic (IDDM) patients are characterized by an increase in the smaller VLDL particles, considered to be the most atherogenic. Since blood glucose control is one of the main regulators of lipid metabolism in diabetic patients, it could influence the shift in the distribution of VLDL subfractions towards smaller particles. To evaluate this possibility, VLDL subfractions, post-heparin lipoprotein lipase and hepatic lipase activities have been evaluated in male IDDM patients with either unsatisfactory blood glucose control (group 1, HbA1c > 8%, n = 18) or good blood glucose control (group 2, HbA1c < 8%, n = 16) and in 16 normoglycaemic individuals. The three groups were comparable for sex, age, body mass index, and plasma lipid levels. Three VLDL subfractions (large, Svedberg flotation unit (Sf) 175-400; intermediate, Sf 100-175; small, Sf 20-100) were separated by density gradient ultracentrifugation and analysed for cholesterol, triglyceride, and phospholipid levels. When compared to control subjects both groups of IDDM patients showed a clear shift in VLDL subfraction distribution with a significant increase in the proportion of small VLDL (group 1; 49 +/- 2%; p < 0.005; group 2: 51 +/- 3%, p < 0.01; control subjects 40 +/- 2%) (mean +/- SEM) in relation to total VLDL. By contrast, the absolute lipid concentration of small VLDL was higher only in group 1, compared to control subjects (35 +/- 4 vs 27 +/- 3 mg/dl, p = 0.05). Post-heparin hepatic lipase activity was significantly reduced in both IDDM groups (group 1: 254 +/- 19 mU/ml, p < 0.05; group 2: 202 +/- 19 mU/ml, p < 0.005; control subjects 317 +/- 31 mU/ml). In conclusion, normolipidaemic IDDM patients show an increase in the smallest VLDL, whatever their degree of blood glucose control. However, this abnormality may be clinically relevant only in patients with unsatisfactory blood glucose control, since absolute lipid concentration of these potentially atherogenic particles is only increased in this group.

Adult↗
PubMed1995

Apolipoprotein AI-CIII-AIV genetic polymorphisms and coronary heart disease in type 2 diabetes mellitus.

The aim of this study was to verify whether or not the increased prevalence of coronary heart disease (CHD) commonly observed in patients with type 2 diabetes mellitus is related to a genetic background involving restriction fragment length polymorphisms (RFLPs) of apolipoproteins. On the basis of a case-control design, 62 type 2 diabetic patients with CHD (confirmed by clinical history and electrocardiogram) and 62 age- and sex-matched diabetic subjects without CHD were enrolled. In each of them RFLPs of the apolipoprotein CIII gene (S1 or S2 allele) and AI promoter region (A or G allele), together with fasting plasma lipids and apolipoproteins levels, were assessed. The rare S2 allele was found significantly (P = 0.05) more frequently in patients with CHD, and its related S1S2 genotype was associated with higher plasma levels of total cholesterol (P = 0.01), triglycerides (P = 0.007) and apo B (P = 0.001) than the S1S1 genotype. The A allele was more frequent (P = 0.004) in patients without CHD and was associated with lower plasma cholesterol (P = 0.0001), low-density lipoprotein (LDL)-cholesterol (P = 0.0001) and apo B (P = 0.005). The S1/A haplotype was more frequent (P = 0.05) in patients without CHD and was associated with the lowest plasma lipid levels. These results suggest that genetic factors, related to the apo AI-CIII-AIV gene cluster, could play a role in the development of CHD in type 2 diabetic patients, probably through modification of their plasma lipid pattern.

Alleles↗
PubMed1995

Lipoprotein(a) concentrations in non-insulin-dependent diabetes mellitus and borderline hyperglycemia: a population-based study.

The objective of the study was to compare lipoprotein(a) [Lp(a)] concentrations in population-based samples of individuals with non-insulin-dependent diabetes mellitus (NIDDM), borderline hyperglycemia, and normoglycemia. From 2,740 male Italian Telephone Company employees aged 40 to 59 years participating in a health screening, we selected all those with NIDDM (n = 100) plus a random sample of 950 nondiabetic individuals. Diabetes was defined as fasting plasma glucose (FPG) of at least 140 mg/dL or current use of hypoglycemic drugs. Among nondiabetic individuals, 854 were defined as normoglycemic (FPG < 115 mg/dL) and 95 were defined as borderline hyperglycemic (115 < FPG < 140 mg/dL). Lp(a) level was measured on frozen plasma by enzyme-linked immunosorbent assay. Lp(a) concentrations were similar in people with NIDDM, borderline hyperglycemia, and normoglycemia: 11.2 +/- 14, 14.1 +/- 20, and 13.9 +/- 18 mg/dL, respectively (F = 1.03). Accordingly, the proportion of subjects with Lp(a) levels of at least 30 mg/dL was comparable in the three groups (12%, 15%, and 14%; chi 2 = 3.95, P = .41). Results were not confounded by differences in age, body mass index (BMI), waist to hip ratio, plasma lipids, alcohol consumption, physical activity, and use of drugs. Furthermore, within the diabetic group Lp(a) levels were not significantly different for those on diet only versus those on oral agents (10.8 +/- 14.1 v 11.7 +/- 14.7, P = .7) or for people with FPG of at least 180 as compared with people with FPG less than 180 mg/dL (9.9 +/- 12.8 v 11.5 +/- 14.8, P = .5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Dietary carbohydrates and glucose metabolism in diabetic patients.

Dietary carbohydrates represent one of the major sources of energy for the human body. However, the main (if not the only) therapy for diabetes since ancient times has been based on reducing dietary carbohydrates drastically because of their effects on blood glucose levels. The introduction of insulin in the 1920s and then of oral hypoglycaemic drugs led to various studies evaluating the biochemical characteristics of carbohydrates and their effects on glucose metabolism in diabetic patients. This review considers the role of dietary carbohydrates in the diet of diabetic patients in the light of the most recent studies and provides a short summary of the biochemistry of carbohydrates and the physiology of carbohydrate digestion.

Blood Glucose↗
PubMed1994

Sequence of the gene encoding an alkaline serine protease of thermophilic Bacillus smithii.

The complete nucleotide sequence of the gene encoding an alkaline serine protease from Bacillus smithii has been determined. Degenerate oligodeoxyribonucleotide primers were used to prime the amplification of a 507-bp sequence of the gene. This sequence was successively used for constructing new primers applied in inverse polymerase chain reaction, using as template self-ligated DNA fragments. The deduced amino-acid sequence is compared to serine proteases from B. amyloliquefaciens, B. licheniformis, B. subtilis and Thermus aquaticus.

Amino Acid Sequence↗
PubMed1994

Long term metabolic effects of two dietary methods of treating hyperlipidaemia.

OBJECTIVES: To compare the long term metabolic effects of two diets for treating hyperlipidaemia. DESIGN: Randomised controlled study: after three weeks of normal (control) diet, subjects were randomly allocated to one of two test diets and followed up for six months. SETTING: Lipid clinic of tertiary referral centre in Naples. SUBJECTS: 63 subjects with primary type IIa and IIb hyperlipoproteinaemia entered the study, and 44 completed it. Exclusion criteria were taking drugs known to influence lipid metabolism, evidence of cardiovascular disease, homozygous familial hypercholesterolaemia, and body mass index over 30. INTERVENTIONS: Two test diets with reduced saturated fat (8%) and cholesterol (approximately 200 mg/day): one was also low in total fat and rich in carbohydrate and fibre, and the other was low in carbohydrate and fibre and rich in polyunsaturated and monounsaturated fats. MAIN OUTCOME MEASURES: Fasting plasma lipid and lipoprotein concentrations; blood glucose, insulin, and triglyceride concentrations before and after a test meal. RESULTS: In comparison with the control diet, both test diets induced significant and similar decreases in low density lipoprotein cholesterol concentrations (by a mean of 0.72 (SE 0.15) mmol/l, P < 0.001, for low total fat diet; by 0.49 (0.18) mmol/l, P < 0.05, for high unsaturated fat diet) and plasma triglyceride concentrations (by 0.21 (0.09) mmol/l, P < 0.05, for low total fat diet; by 0.39 (0.15) mmol/l, P < 0.05, for high unsaturated fat diet), while high density lipoprotein cholesterol concentrations after fasting and plasma glucose and insulin concentrations during test meals were not modified by either diet. CONCLUSIONS: Both test diets are suitable (alone or in combination) for treatment of hypercholesterolaemia.

Cholesterol↗
PubMed1994

New shuttle vector for cloning in Bacillus stearothermophilus.

Cloning vector plasmid pRP9 was constructed on the basis of the broad host-range plasmid pLM6. pRP9 was a small plasmid (2.9 kb), possessed a convenient polyrestriction site sequence and efficiently transformed Bacillus subtilis, Bacillus stearothermophilus and Escherichia coli. Furthermore, pRP9 presented a very high segregational stability in Bacillus hosts. Also, the structural stability in Bacillus strains, grown under selective pressure, of pRP9 carrying a 3-kb fragment, was high. No single-stranded and high-molecular weight pRP9 DNA was found in B. stearothermophilus. The host/vector systems described possessed all the properties required for efficient gene cloning.

Bacillus subtilis↗
PubMed1994

[Neonatal screening for congenital hip dislocation. Indication of ultrasonography from a systematic study correlating clinical findings and ultrasonography].

INTRODUCTION: The aim of our study was to verify the correlation between clinical and sonographic screening for CDH. MATERIALS AND METHODS: Clinical and sonographic screening was carried out in 1000 newborns (2000 hips) during the first week of life. Anamnestic risk factors were evaluated and clinical examination was performed using the BARLOW, Le DAMANY and ORTOLANI maneuvers. We also took into account a possible limitation of abduction due to adductor hypertonia and the presence of a hip crepitation. All hips were evaluated by ultrasound examination using Graf's morphologic method. We considered as clinically pathological the positive BARLOW, Le DAMANY and ORTOLANI hips and "doubtful" the stable hips having "crepitation" or "hypertonia of the adductors". The hips considered pathological with the ultrasound were the hips 2c, 3a and 3b according to GRAF. RESULTS: 1) Hips clinically pathological (BARLOW, Le DAMANY and ORTOLANI): 150 (7.5 per cent). 2) The clinically stable hips but "doubtful":--crepitation: 105 (5.25 per cent); adductor hypertonia: 86 (4.3 per cent), total 191 (9.55 per cent). 3) Hips clinically normal but with at least anamnestic risk factor: 198 (9.9 per cent); 4) Hips clinically normal but without anamnestic risk factor: 1461 (73.05 per cent). 5) Hips echographically pathological, that is 2c, 3a and 3b according to Graf: 124 (6.2%) and particularly 2c: 61 (3.05 per cent), 3a: 61 (3.05 per cent) and 3b: 2 (0.1 per cent). DISCUSSION: 1) In the clinically pathological hips (BARLOW positive) 36 were echographically pathological with a clinical-sonographic correlation of 28.3 per cent (36 out of 127); all the ORTOLANI positive hips, were echographically pathological (100 per cent (23 out of 23)). In doubtful hips, sonograms were pathological in 17 of 105 hips with "crepitation" (0.85 per cent) and in 13 of 86 hips with "adductor hypertonia" (0.65 per cent). 2) The clinically and echographically pathological hips at birth, that is 2c, 3a and 3b, must be followed for months. At follow up they showed in almost all the cases an evolution towards normality. It is, therefore, indicated to repeat the clinical and sonographic examination in the first month, before undertaking any kind of treatment. 3) Finally, 12 hips, 0.6 per cent, presenting pathological sonographic type 2c and 3a, were found clinically normal. Nevertheless, almost all of these hips evolved normally. From this study only 0.05 per cent of clinically normal hips presented, later, a dysplasia of the acetabulum. Analysis of the results clearly showed that ultrasound examination may be an excellent help to clinical examination which, if well performed, has top priority for early diagnosis of C.D.H. CONCLUSION: The clinical examination, carefully performed in the first days of life, has priority because it allows discovering a pathological hip or a hip at risk. The sonographic examination is a useful image complementing the clinical examination because it allows confirmation of the diagnosis and follow up of the morphologic evolution of the hip with an inoffensive method and it can give indications for possible treatment. From our study we may conclude that at birth a clinical screening is preferable and that the ultrasound study is to be reserved for pathological, doubtful or at risk hips.

Data Interpretation, Statistical↗
PubMed1994

[The utilization of dry chemistry methods in a campaign to identify risk factor of cardiovascular diseases].

Dry chemistry methods on a Kodak Ektachem DT 60 instrument have been evaluated during a large scale (60,000 employees of the Italian Telephone Company) screening for the prevalence of cardiovascular risk factors. Comparison between dry chemistry methods on serum samples and liquid phase methods on the same samples yielded the following correlation coefficients: .991 (n = 100) for total cholesterol, .962 (n = 50) for high density lipoprotein (HDL) cholesterol, .987 (n = 100) for triglycerides, .997 (n = 50) for glucose, and .991 (n = 50) for uric acid. A 12% overestimation of serum triglycerides was observed with dry chemistry methods as compared to liquid phase methods. Accuracy and precision of these dry chemistry methods were evaluated by daily (n = 271 days) determinations of all the above parameters on each of two reference sera (low and high concentration). Dry chemistry methods average bias estimates (observed value - expected value)/expected value) x 100, measuring method's accuracy, were: 4.2% for total cholesterol, 1.2% for HDL cholesterol, 3.6% for triglycerides, 3.0% for glucose, 4.6% for uric acid. Average coefficients of variation (standard deviation/mean x 100, measuring method's precision, were: 5.0% for total cholesterol, 6.3% for HDL cholesterol, 5.9% for triglycerides, 3.6% for glucose, 7.2% for uric acid. Dry chemistry methods by Kodak Ektachem DT 60 proved highly comparable with liquid phase methods. Considering their level of accuracy and precision they can be recommended as quick and simple methods for population screenings.

Blood Glucose↗
PubMed1993

Mutation in a conserved motif next to the insulin receptor key autophosphorylation sites de-regulates kinase activity and impairs insulin action.

We have recently reported two non-insulin-dependent diabetic patients exhibiting a heterozygous point mutation (R1152-Q) next to the key tyrosine autophosphorylation sites (Y1146, Y1150, Y1151) of the insulin receptor. In the present study, we demonstrate that the Q1152 mutation alters a previously unrecognized consensus sequence in the insulin receptor family of tyrosine kinases. To define the effect of this alteration on insulin receptor function, the mutant insulin receptor (Q1152) was constructed and overexpressed in NIH-3T3 cells. In spite of normal insulin binding, "in vivo" and "in vitro" autophosphorylation as well as transphosphorylation by the wild-type receptor (WT) were deficient in Q1152 as compared with the transfected WT receptors. Insulin-stimulated kinase activity toward poly(Glu, Tyr) 4:1 and the endogenous substrates p120 and p175 were also impaired in Q1152. However, insulin-independent kinase activity of Q1152 was 2-5-fold higher than that of WT. While insulin stimulated 2-deoxyglucose uptake and glycogen synthase activity in WT-transfected cells with a sensitivity proportional to receptor number, no insulin stimulation was observed in Q1152 cells. Similar to the kinase, insulin-independent glycogen synthase activity and 2-deoxyglucose uptake were 2-fold higher in Q1152 than in either WT or parental cells. We conclude that the Q1152 mutation deregulates insulin receptor kinase and generates insulin insensitivity in cells. Alterations in this highly conserved region of the insulin receptor may contribute to non-insulin dependent diabetes mellitin pathogenesis in humans.

3T3 Cells↗
PubMed1993

Abnormal distribution of VLDL subfractions in type 1 (insulin-dependent) diabetic patients: could plasma lipase activities play a role?

Very low density lipoproteins (VLDL) have an abnormal lipid composition in Type 1 (insulin-dependent) diabetic patients. Since VLDL represent a heterogeneous lipoprotein class, this might be due either to a shift in the distribution or to an abnormal composition of VLDL subclasses or both. In order to investigate these possibilities and to evaluate possible pathogenetic mechanisms, lipid composition (non-esterified and esterified cholesterol, triglycerides, phospholipids) of four VLDL subfractions of decreasing size (A: Svedberg flotation unit [Sf] > 400, B: Sf > 400, B: Sf 175-400, C: Sf 100-175, D: Sf 20-100), isolated by density gradient preparative ultracentrifugation, and plasma post-heparin lipolytic activity (lipoprotein lipase and hepatic lipase) were evaluated in 13 male normolipidaemic insulin-dependent diabetic patients in good glycaemic control (HbAlc 6.9 +/- 0.5%) (mean +/- SEM) and 9 male control subjects matched for age, body mass index and plasma lipid values. Compared to control subjects, diabetic patients showed a reduced total lipid concentration of VLDL of intermediate size (B and C) reaching statistical significance only for VLDL C (0.16 +/- 0.02 vs 0.24 +/- 0.03 mmol/l; p < 0.05). Expressing each VLDL subfraction as percent of the total VLDL lipid concentration, a significant decrease in particles of intermediate size (C) (20.5 +/- 1.6 vs 27.9 +/- 1.5%; p < 0.005) was present, which was compensated by an increase in the smallest ones (D) (50.5 +/- 2.7 vs 37.4 +/- 3.1%; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Haemodynamic effects of pressure support and PEEP ventilation by nasal route in patients with stable chronic obstructive pulmonary disease.

BACKGROUND: Intermittent positive pressure ventilation applied through a nasal mask has been shown to be useful in the treatment of chronic respiratory insufficiency. Pressure support ventilation is an assisted mode of ventilation which is being increasingly used. Invasive ventilation with intermittent positive pressure, with or without positive end expiratory pressure (PEEP), has been found to affect venous return and cardiac output. This study evaluated the acute haemodynamic support ventilation by nasal mask, with and without the application of PEEP, in patients with severe stable chronic obstructive pulmonary disease and hypercapnia. METHODS: Nine patients with severe stable chronic obstructive pulmonary disease performed sessions lasting 10 minutes each of pressure support ventilation by nasal mask while undergoing right heart catheterisation for clinical evaluation. In random order, four sessions of nasal pressure support ventilation were applied consisting of: (1) peak inspiratory pressure (PIP) 10 cm H2O, PEEP 0 cm H2O; (2) PIP 10 cm H2O, PEEP 5 cm H2O; (3) PIP 20 cm H2O, PEEP 0 cm H2O; (4) PIP 20 cm H2O, PEEP 5 cm H2O. RESULTS: Significant increases in arterial oxygen tension (Pao2) and saturation (Sao2) and significant reductions in arterial carbon dioxide tension (PaCO2) and changes in pH were observed with a PIP of 20 cm H2O. Statistical analysis showed that the addition of 5 cm H2O PEEP did not further improve arterial blood gas tensions. Comparison of baseline values with measurements performed after 10 minutes of each session of ventilation showed that all modes of ventilation except PIP 10 cm H2O without PEEP induced a small but significant increase in pulmonary capillary wedge pressure. In comparison with baseline values, a significant decrease in cardiac output and oxygen delivery was induced only by the addition of PEEP to both levels of PIP. CONCLUSIONS: In patients with severe stable chronic obstructive pulmonary disease and hypercapnia, pressure support ventilation with the addition of PEEP delivered by nasal mask may have short term acute haemodynamic effects in reducing oxygen delivery in spite of adequate levels of SaO2.

Aged↗