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Biomedical subjects

M Sergi

Publications and source records attributed to M Sergi.

At least 19 recordsLinked to original sources
PubMed1999

Periodic breathing during sleep in patients affected by fibromyalgia syndrome.

Seventeen patients affected by fibromyalgia syndrome (FMS) (16 females and one male) and 17 matched healthy subjects underwent formal polysomnography, a sleep questionnaire and lung function tests. FMS patients slept significantly less efficiently than the healthy controls (p<0.01), had a higher proportion of stage 1 sleep (mean+/-SD, 21+/-6% versus 11+/-4%; p<0.001), less slow wave sleep (p<0.01) and twice as many arousals per hour of sleep (p<0.001). The respiratory pattern of FMS patients showed a high occurrence of periodic breathing (PB) (15+/-8% of total sleep time) in 15/17 patients, versus 2/17 control subjects. The short length of apnoeas and hypopnoeas did not affect the apnoea/hypopnoea index (5.1+/-3.5 versus 3.2+/-1.6; NS), but FMS patients had a greater number of desaturations per hour of sleep (8+/-5 versus 3+/-3; p<0.01). Pulmonary volumes did not differ between the two groups, but FMS patients had a lower transfer factor of the lung for carbon monoxide (TL,CO (5.8+1 versus 7.7+1 mmol x min(-1) x kPa(-1); p=0.001). PB occurrence correlated with TL,CO (r=-0.62; p=0.01), number of desaturations (r=0.76, p=0.001) and carbon dioxide tension in arterial blood (Pa,CO2) (r=-0.50; p=0.05). Stepwise multiple linear regression analysis showed desaturation frequency (p=0.0001) and TL,CO (p=0.029) to be the best predictors of PB percentage (R2 0.73; p=0.0001). Patients complaining of daytime hypersomnolence had a higher number of tender points, about twice as many arousals per hour and a lower sleep efficiency than patients who did not report this symptom. TL,CO was more impaired and the occurrence of PB was higher. The occurrence of periodic breathing in fibromyalgia syndrome patients, which was previously unreported, and is shown to be linked to a reduction of transfer factor of the lung for carbon monoxide could play a major role in the symptoms of poor sleep of these patients.

Disorders of Excessive Somnolence↗
PubMed1998

Validity of diurnal sleep recording performed by an ambulatory device in the diagnosis of obstructive sleep apnoea.

The objective of this study was to compare the results of oxygen desaturations and sleep apnoea during a daytime nap (D) versus nocturnal sleep (N) evaluation, recorded by a portable multichannel monitoring device in patients with a clinical suspicion of obstructive sleep apnoea (OSA). Two polysomnographic studies were performed, by means of the Healthdyne NightWatch System, in 82 subjects (mean age 57.9 years). No difference was found in the apnoea + hypopnoea index (AHI) and mean SaO2 between D and N recordings. At an AHI threshold of 20, in the D recordings, compared to the N ones, the sensitivity was 91% and the specificity 100%. A good correlation was found for AHI and oxygen desaturation index (ODI) between the two experimental conditions (r = 0.89 and 0.79, respectively). Our study shows that D recordings seem to be accurate for OSA diagnosis in the majority of patients with a clinical suspicion of sleep apnoea syndrome.

Female↗
PubMed1998

Prescription of nCPAP and nBIPAP in obstructive sleep apnoea syndrome: Italian experience in 105 subjects. A prospective two centre study.

Nasal continuous positive airway pressure (nCPAP) is the current treatment of obstructive sleep apnoea syndrome (OSAS). The indications of bilevel pressure support ventilation (BIPAP PSV) in OSAS patients remain controversial. The purpose of this investigation was to verify the frequency of prescription of BIPAP PSV in a group of OSAS patients when CPAP was ineffective or not tolerated during titration. The study included 286 consecutive patients > or = 18 years of age referred to two Sleep laboratories for sleep related breathing disorders (SRBD) between December 1994 and November 1995. Of these, 130 patients were enrolled and 105 (88 males, 77 females) with moderate to severe OSAS completed the study and were finally analysed. After a full night diagnostic polysomnography (PSGD), patients had a second full night PSG under nCPAP (PSGT). If nCPAP was not tolerated, or failed to correct breathing abnormalities during sleep, a second PSGT was performed, using a BIPAP PSV. Our study shows that nCPAP (mean 8.5 +/- 2.0 cmH20) was considered a satisfactory therapy in 81 patients (77%). Twenty four (23%) required BIPAP PSV (mean IPAP 13.9 +/- 2.9 cmH20). We found the highest prevalence of BIPAP in patients with OSAS associated to obesity hypoventilation syndrome (OHS) (11 of 17) and in OSAS associated to chronic obstructive pulmonary disease (COPD) (nine of 16). Patients treated with BIPAP PSV were more obese and had a higher PaCO2 and sleep-related desaturations and a lower FEV1, FVC, FEV1/FVC and PaO2. In conclusion our study shows that CPAP therapy in the effective therapeutic option in the majority of patients with OSAS. There is a subset of patients with OSAS associated to COPD or to OHS in whom BIPAP PSV may be a better treatment modality.

Chi-Square Distribution↗
PubMed1996

Effects of aging and of chronic obstructive pulmonary disease on RR interval variability.

Clinical and experimental investigations suggest that spectral analysis of RR interval variability might be employed to assess changes in autonomic regulation of the SA node occurring in various chronic, cardiac or respiratory conditions. We studied three groups of subjects: young healthy, older healthy, and old patients with chronic obstructive pulmonary disease (COPD), considering RR interval and breathing, i.e. tidal volume, variability in the frequency domain (AR algorithms), in order to obtain markers of the sympathetic and vagal modulation of the SA node [by way, respectively, of the low (LF) and high frequency (HF) spectral components]. The gain of the relationship between tidal volume and heart period variation (index beta) was also examined. COPD patients demonstrated a reduced resting RR variance with maintained spectral power distribution; upon tilting they did not manifest the usual increase of LF (and attendant decrease of HF) component. Additionally, we observed that the index beta at rest was significantly reduced in older as opposed to younger subjects. This index was also reduced by tilt, in both groups. In patients the index beta was reduced as compared to the group of similar age and younger subjects, and did not diminish further with tilt. This study indicates that in patients with COPD, sympathetic excitatory modulation of the SA node is depressed. Furthermore, the index beta, which provides an assessment of the gain of respiratory modulation of RR interval variability is significantly reduced in patients, as compared to healthy subjects of similar age. These abnormalities of autonomic control, may represent a functional correlation of the hyperinflated state present in this clinical condition which can be assessed non-invasively with spectral analysis of RR interval and respiration.

Adult↗
PubMed1989

Cardiac output with CO2 rebreathing method in CAPD patients.

The aim of this study is to evaluate cardiac output (CO) with CO2 rebreathing method (RCO2) in patients (pts) on CAPD. We have studied 15 pts on CAPD from at least 6 months, the mean (+/- SD) age was 55 +/- 4 years, mean (+/- SD) hemoglobin was 10 +/- 2 gr/dl. The respiratory tests excluded obstructive or restrictive broncopneumopathies. Electrocardiograms and B-mode echocardiograms were normal. RCO2 was evaluated using the FICK formula: CO = VCO2/CvCO2 - CaCO2 where VCO2 is CO2 production; CvCO2 is the CO2 content in venous mixed blood; CACO2 is arterial CO2. VCO2 was obtained by collecting expired air into a Douglas bag during respiration at rest for 4 minutes. CvCO2 was obtained after 10-15 seconds of respiration in a mixture of 7% CO2 in O2. CaCO2 was obtained at CO2 end-tidal capnogram. RCO2 was performed in CAPD with full and empty abdomen. The mean (+/- SD) CO was 2.3 +/- 1.04 l/min with both full and empty abdomen, values below those theoretically calculated, taking into account the age and body surface (4.7 +/- 0.6 l/min P less than 0.0005). The reduction of CO is not induced by left ventricular insufficiency, but such phenomenon could be attributed to a redistribution of body fluid between intra and extracellular, in favour of the intracellular compartment. Therefore the increase in hematocrit and total plasma proteins can be fictitious.

Aged↗
PubMed1986

Mean transit time, forced expiratory volume and age in healthy male smokers and non-smokers.

We studied 67 healthy males aged 20-30 years, 29 of them non-smokers and 38 smokers. In smokers, forced expiratory volume (FEV), 1 s forced expiratory volume (FEV1) and peak flow (PF) were significantly lower than in non-smokers, while the FEV1/FEV ratio, flows and mean transit time (MTT) compared well. MTT appeared directly related to age and negatively to FEV1/FEV, with no difference between the two groups, but MTT was directly related to FEV in non-smokers and negatively in smokers. Multiple regression analysis, MTT = a + b(FEV)+c(age), showed that parameters b and c were significantly different between smokers and non-smokers and, in the former, parameter b was negative. In non-smokers the effects of age and FEV on MTT were roughly the same, but in smokers MTT was influenced above all by age, probably because MTT measured the effects of continued smoking.

Adult↗
PubMed1985

Ventilatory response to carbon dioxide and to isometric muscle contraction after administration of placebo, propranolol, mepindolol and salbutamol.

Healthy males (23-29 years) volunteered as subjects. We studied the ventilatory response to carbon dioxide and to isometric exercise (50% of maximum voluntary contraction) after administration of propranolol (20 mg), mepindolol (5 mg), salbutamol (20 mg) and placebo (single dose orally). The increase of pulmonary ventilation (VE) activated by central (CO2) and reflex stimulus (hand-grip) did not differ statistically between the four drugs. Analysis of VE in terms of inspiratory drive (Vt/Ti) and timing ratio (Ti/Ttot) showed that during CO2 stimulation mepindolol and salbutamol increased VE predominantly by the increase of Vt/Ti, presumably through the direct stimulation on the respiratory center. During rebreathing, Ti/Ttot increased significantly after administration of placebo and propranolol, so VE increased by a rise of Vt/Ti and by an increase of an effective 'timing component' (Ti/Ttot). Propranolol does not modify the ventilatory response to CO2 and hand-grip when VE is analyzed in terms of Vt/Ti and Ti/Ttot.

Adult↗
PubMed1984

Ventilatory volumes, flow rates, transfer factor and its components (membrane component, capillary volume) in obese adults and children.

We have studied the ventilatory volumes, flow rates, transfer factor and its components (membrane component and capillary volume) in 19 women and 23 children with moderate obesity. The adults showed restrictive defects, but the pulmonary volumes of children were within normal range. Peak flow, flows at 75 and 50% forced expiratory volume, in two groups, normalized for the forced expiratory volume, did not differ between the two groups. The transfer factor was reduced in adults, because of reduction of the alveolar volume, the membrane component was low in both groups; transfer factor and membrane component normalized for functional residual capacity were not different between the two groups. The capillary volume was greater in children than adults, because the excess body weight was greater for the children. In simple obesity, the main alteration is the decrease of distensibility of the chest wall that becomes worse as time goes on and is the cause for the alterations in ventilatory volume, flow and transfer factor.

Adult↗
PubMed1981

Ventilatory pattern during handgrip on normal man.

We studied the ventilatory response to an isometric handgrip (50% maximum voluntary contraction) in 7 young normal subjects. VE increased significantly during isometric contraction due to increases in Vt/Ti (the mean inspiratory flow) and Ti/Ttot (the timing component of ventilation). The increase in Vt/Ti is greater than that in Ti/Ttot; thus, the contribution of the neural inspiratory drive is predominant in increasing the pulmonary ventilation during a handgrip.

Hand↗
PubMed1980

Pulmonary diffusing capacity and its components (DM and Vc) in young, healthy smokers.

We have studied the diffusing capacity and its components (DM and Vc) in two groups of 9 males, healthy, smokers and nonsmokers, with similar age, biometric characteristics and spirographic values. Also, BT was not different between the two groups, because the smokers were asked to stop smoking 12 h before the test. Our data showed that TF and DM are significantly lower in smokers than in nonsmokers (p less than 0.005 and less than 0.01, respectively, while Vc was not different between the two groups and confirm that Vc is influenced by COhb level.

Adult↗
PubMed1980

Ventilatory and pressor response to isometric exercise in normal subjects.

We studied in 8 young, healthy males, the behaviour of heart rate (HR), systolic blood pressure at the upper (SBPUL) and lower (SBPLL) resting limbs, pulmonary ventilation (VE), oxygen uptake (VO2) and production of CO2 (VCO2) during and after two levels of isometric effort (handgrip at 50 and 100% maximum voluntary contraction; MVC). HR, SBPLL, VE, VO2, and VCO2 did not vary between the two efforts, but SBPUL is significantly different between them. The possible mechanism and predominant role of nervous reflexes upon the pressor and ventilatory response to isometric exercise are discussed.

Adult↗
PubMed1980

[Effects of handgrip on cardiovascular and respiratory apparatus of healthy young subjects (author's transl)].

We have studied, in eight healthy subjects, aged 22-26 years, some cardiovascular and respiratory effects, during maximal and half-maximal isometric effort, four minutes lasting, performed with hand (handgrip). During contraction and 15 minutes lasting recovery, heart rate, arterial systolic pressure at resting arm and at limb, pulmonary ventilation, VO2 and VCO2 have been evaluated. The data of the two tests have been submitted to the Student's test. During isometric contraction and recovery, heart rate rapidly increases and decreases, respectively, without significant differences between the two contractions. The abrupt increase of the systolic arterial pressure is greater during maximal work, at resting arm; arterial pressure at limb increases rapidly during contraction, but do not varies between the two efforts. These arterial pressure responses to isometric contraction presumably are related to a neurogenic vasoconstriction. During recovery of maximal work, the systolic arterial pressure, at limb, is significantly greater than basal values from 5th to 15th minute and versus the half maximal effort at 7th, 10th and 15th minute, presumably because the vasoconstriction is still effective. Pulmonary ventilation, VO2 and VCO2 increase during contraction; VO2 and VCO2 further increase after 10 minutes of recovery, probably because the debt of O2 is repaid.

Adult↗