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Biomedical subjects

J Roca

Publications and source records attributed to J Roca.

At least 109 records · Page 6Linked to original sources
PubMed1999

Long term outcome of soybean epidemic asthma after an allergen reduction intervention.

BACKGROUND: Asthma outbreaks due to the inhalation of soybean dust released from handling of soybean in the city harbour occurred in Barcelona, Spain from 1981 to 1987. The installation of bag filters in the responsible silo was followed by a substantial reduction of airborne soybean dust released into the atmosphere and the disappearance of asthma outbreaks. A study was undertaken to assess the relevant outcomes in asthma patients affected by soybean epidemic asthma eight years after this environmental intervention. METHODS: A repeat case-control study was performed in 1995 on a population of subjects with epidemic and non-epidemic asthma previously assessed in 1989. The same protocol was used in both surveys to collect data from patients via a questionnaire and respiratory function, skin and laboratory tests were performed under blinded conditions with regard to epidemic and non-epidemic status. Environmental soybean allergen in pollution filters was measured by means of a RAST inhibition technique. RESULTS: During 1995 and 1996 the 24 hour mean airborne levels of soybean allergen on a sample of 39 unloading days (range 31-269 U/m(3)) were systematically below the lowest level ever detected during an epidemic day (1500 U/m(3)). Measurable levels of serum IgE antibodies against soybean were still present in 55% of patients with epidemic asthma compared with 6.0% of those with non-epidemic asthma (p<0.05). These proportions were almost identical to those observed in 1989. The proportion of patients with soybean asthma with symptoms in 1989 who reported the absence of symptoms in 1995 was similar to the control subjects, so most of the relative risks (RRs) of improvement were near to 1. The only statistically significant differences between the two groups were a smaller proportion of patients with epidemic asthma showing improvement in terms of being woken up by attacks of coughing (RR improvement 0.47; 95% CI 0.22 to 0.99) and the need for treatment at the emergency room (RR improvement 0.63; 95% CI 0.41 to 0.96). CONCLUSIONS: Eight years after a large reduction in the levels of airborne soybean allergen half of the former soybean epidemic asthma patients were still sensitised to soybean. These results indicate an initial improvement in soybean epidemic asthma in the two years following the intervention with no further improvement in subsequent years.

Allergens↗
PubMed1999

Evidence of O2 supply-dependent VO2 max in the exercise-trained human quadriceps.

Maximal O2 delivery and O2 uptake (VO2) per 100 g of active muscle mass are far greater during knee extensor (KE) than during cycle exercise: 73 and 60 ml. min-1. 100 g-1 (2.4 kg of muscle) (R. S. Richardson, D. R. Knight, D. C. Poole, S. S. Kurdak, M. C. Hogan, B. Grassi, and P. D. Wagner. Am. J. Physiol. 268 (Heart Circ. Physiol. 37): H1453-H1461, 1995) and 28 and 25 ml. min-1. 100 g-1 (7.5 kg of muscle) (D. R. Knight, W. Schaffartzik, H. J. Guy, R. Predilleto, M. C. Hogan, and P. D. Wagner. J. Appl. Physiol. 75: 2586-2593, 1993), respectively. Although this is evidence of muscle O2 supply dependence in itself, it raises the following question: With such high O2 delivery in KE, are the quadriceps still O2 supply dependent at maximal exercise? To answer this question, seven trained subjects performed maximum KE exercise in hypoxia [0.12 inspired O2 fraction (FIO2)], normoxia (0.21 FIO2), and hyperoxia (1.0 FIO2) in a balanced order. The protocol (after warm-up) was a square wave to a previously determined maximum work rate followed by incremental stages to ensure that a true maximum was achieved under each condition. Direct measures of arterial and venous blood O2 concentration in combination with a thermodilution blood flow technique allowed the determination of O2 delivery and muscle VO2. Maximal O2 delivery increased with inspired O2: 1.3 +/- 0.1, 1.6 +/- 0.2, and 1.9 +/- 0.2 l/min at 0.12, 0.21, and 1.0 FIO2, respectively (P < 0.05). Maximal work rate was affected by variations in inspired O2 (-25 and +14% at 0.12 and 1.0 FIO2, respectively, compared with normoxia, P < 0.05) as was maximal VO2 (VO2 max): 1.04 +/- 0.13, 1. 24 +/- 0.16, and 1.45 +/- 0.19 l/min at 0.12, 0.21, and 1.0 FIO2, respectively (P < 0.05). Calculated mean capillary PO2 also varied with FIO2 (28.3 +/- 1.0, 34.8 +/- 2.0, and 40.7 +/- 1.9 Torr at 0.12, 0.21, and 1.0 FIO2, respectively, P < 0.05) and was proportionally related to changes in VO2 max, supporting our previous finding that a decrease in O2 supply will proportionately decrease muscle VO2 max. As even in the isolated quadriceps (where normoxic O2 delivery is the highest recorded in humans) an increase in O2 supply by hyperoxia allows the achievement of a greater VO2 max, we conclude that, in normoxic conditions of isolated KE exercise, KE VO2 max in trained subjects is not limited by mitochondrial metabolic rate but, rather, by O2 supply.

Adult↗
PubMed1999

Specific prognostic factors for secondary pancreatic infection in severe acute pancreatitis.

BACKGROUND/AIMS: The aim of the present study was to investigate whether there are specific prognostic factors to predict the development of secondary pancreatic infection (SPI) in severe acute pancreatitis in order to perform a computed tomography-fine needle aspiration with bacteriological sampling at the right moment and confirm the diagnosis. METHODS: Twenty-five clinical and laboratory parameters were determined sequentially in 150 patients with severe acute pancreatitis (SAP) and univariate, and multivariate regression analyses were done looking for correlation with the development of SPI. RESULTS: Only APACHE II score and C-reactive protein levels were related to the development of SPI in the multivariate analysis. A regression equation was designed using these two parameters, and empiric cut-off points defined the subgroup of patients at high risk of developing secondary pancreatic infection. CONCLUSION: The results showed that it is possible to predict SPI during SAP allowing bacteriological confirmation and early treatment of this severe condition.

APACHE↗
PubMed1999

Infusion phlebitis in post-operative patients: when and why.

BACKGROUND: The most common complication of intravenous therapy is infusion phlebitis. This study was done to prospectively assess its frequency in a series of consecutive patients who will undergo surgery, and to identify which variables may predict an increased risk for phlebitis. PATIENTS AND METHODS: 400 consecutive patients who will undergo surgery in a general surgery department were included. Only the first catheter, inserted the day before surgery, was taken into account. Eighteen variables (from the infusion, the catheter and from the patient) were prospectively evaluated for their contribution to the occurrence of phlebitis. RESULTS: 60/400 patients (15%) developed phlebitis, and most of them needed insertion of a further catheter. The univariate analysis showed that patients who developed phlebitis were older, and their pre-operative levels of both blood haemoglobin and neutrophil cound were significantly higher than those in patients who did not develop phlebitis. However, the multivariate analysis only confirmed the association with blood haemoglobin levels: the risk of phlebitis sharply increased in the patients with the highest haemoglobin levels. As to the influence of time on phlebitis development, there was a significant decrease in the day-specific risk, from the 5th day on. COMMENTS: In our series, blood haemoglobin levels were found to be the only variable associated to a higher risk of phlebitis. Besides, in contrast with the recommendations by the Centers for Disease Control, no significant increase in the day-specific risk of phlebitis was found. Thus, a guideline to select the type of catheter to be inserted in an individual patient is suggested.

Adolescent↗
PubMed1999

Inflammatory reaction in pulmonary muscular arteries of patients with mild chronic obstructive pulmonary disease.

Endothelial dysfunction and intimal thickening have been shown in pulmonary arteries (PA) of patients with mild chronic obstructive pulmonary disease (COPD). To investigate whether an inflammatory process related to tobacco smoking might be involved in the development of pulmonary vascular abnormalities in COPD, we characterized the inflammatory cell infiltrate and the endothelium-dependent relaxation in PA of 39 patients who underwent lung resection, divided into three groups: "nonsmokers" (n = 7); "smokers," with normal lung function (n = 12); and "COPD" (n = 20). Endothelium-dependent relaxation was assessed in vitro by exposing PA rings to adenosine diphosphate (ADP). Inflammatory cell types were identified by immunohistochemistry. PA of COPD patients developed lower relaxation in response to ADP than nonsmokers and smokers. The number of inflammatory cells was increased in PA of COPD compared with the other two groups. This cell infiltrate was largely constituted by T lymphocytes. The CD8(+) T-cell subset was increased in both smokers and COPD compared with nonsmokers, yielding a reduction of the CD4(+)/CD8(+) ratio. The intensity of the inflammatory infiltrate correlated with both the endothelium-dependent relaxation and the intimal thickness. We conclude that cigarette smoking induces a CD8(+) T-lymphocyte infiltrate in PA, which is associated with the impairment of the vessel's structure and function, suggesting the potential involvement of an inflammatory process in the pathogenesis of pulmonary vascular abnormalities in the early stage of COPD.

Aged↗
PubMed1999

Effects of endurance training on skeletal muscle bioenergetics in chronic obstructive pulmonary disease.

Physiologic adaptations after an 8-wk endurance training program were examined in 13 patients with chronic obstructive pulmonary disease (COPD) (age, 64 +/- 4 [SD] yr; FEV1, 43 +/- 9% pred; PaO2, 72 +/- 8 mm Hg; and PaCO2, 36 +/- 2 mm Hg) and in eight healthy sedentary control subjects (61 +/- 4 yr). Both pre- and post-training studies included: (1) whole-body oxygen consumption (V O2) and one-leg O2 uptake (V O2leg) during exercise; and (2) intracellular pH (pHi) and inorganic phosphate to phosphocreatine ratio ([Pi]/[PCr]) during exercise; and half-time of [PCr] recovery. After training, the two groups increased peak V O2 (p < 0.05 each) and showed a similar fall in submaximal femoral venous lactate levels (p < 0.05 each). However, control subjects increased peak V E (p < 0.01) and raised peak O2 delivery (p = 0.05), not shown in patients with COPD. Both groups increased post-training O2 extraction ratio (p < 0.05). The most consistent finding, however, was in patients with COPD, who had a substantial improvement in cellular bioenergetics: (1) half-time of [PCr] recovery fell from 50 +/- 8 to 34 +/- 7 s (p = 0.02); and (2) at a given submaximal work rate, [Pi]/[PCr] ratio decreased and pHi increased (p < 0.05 each). We conclude that beneficial effects of training in patients with COPD essentially occurred at muscle level during submaximal exercise.

Aged↗
PubMed1999

A double-blind, placebo-controlled study of the effects of policosanol in patients with intermittent claudication.

This study was undertaken to evaluate the efficacy and tolerability of policosanol, a new cholesterol-lowering drug with concomitant antiplatelet effects, in patients with intermittent claudication. After a baseline period of 6 weeks, 62 patients were randomized to receive, under double-blind conditions, either placebo (31 patients) or policosanol (31), 10 mg twice daily. Walking distances in a treadmill (constant speed 3.2 km/hr, slope 10 degrees) were assessed before and after 6 months of treatment. Both groups were similar at randomization. Policosanol increased significantly (p < 0.01) the initial claudication distance from 132.5+/-13.5 m (baseline) to 205.7+/-36.3 m (after therapy) and the absolute claudication distance (p<0.0001) from 229.5+/-22.0 m to 365.4+/-46.9 m; meanwhile both variables remained unchanged in the placebo group (p<0.05). The reduction of lower limb symptoms showed a greater benefit in the policosanol group. There was no significant change in either group in the ankle/arm pressure ratio. The treatment was well tolerated. There were 10 discontinuations (seven placebo, three policosanol) from the study. Six withdrawals occurred because of adverse events (AE); all were in placebo patients. There were five serious vascular AEs in the placebo group but none in the policosanol group (p<0.05). Overall, 12/31 (38.7%) placebo patients and 3/31 (9.7%) policosanol patients experienced AEs after randomization, which showed a lesser incidence of AEs in the policosanol group (p<0.01). The present study demonstrates a beneficial effect of policosanol in patients with intermittent claudication.

Adult↗
PubMed1999

Infusion phlebitis in patients with acute pneumonia: a prospective study.

STUDY OBJECTIVES: To prospectively assess the relative risk for phlebitis in a series of consecutive patients with pneumonia and to identify risk factors that predict an increased risk for phlebitis. SETTING: Internal medicine department of a tertiary teaching hospital. PATIENTS: Seven hundred sixty-six consecutive patients with acute pneumonia receiving IV therapy. INTERVENTIONS: Only the first catheter was taken into account. There were 308 short lines (a 51-mm, 18-gauge Teflon catheter); 307 midsized lines (a 28-cm, 16-gauge polyvinyl chloride catheter); and 151 long lines (71-cm, 14-gauge plain polyurethane catheter). Eighteen variables were prospectively evaluated in an open, nonrandomized study for their contribution to the occurrence of phlebitis. RESULTS: The overall phlebitis rate was 39%. Phlebitis developed in 53% of patients with short lines, in 41% of patients with midsized lines, and in 10% of patients with long lines, and these catheters remained in place an average (+/- SD) of 3.0+/-2.4 days, 4.6+/-3.4 days, and 7.8+/-6.6 days, respectively. The variables that influenced the development of phlebitis, as determined by multivariate analysis, were the following: type of catheter; blood hemoglobin levels; and IV therapy with either corticosteroids or erythromycin. CONCLUSIONS: According to our data, when the use of a catheter is expected to be required for < or = 36 h, a short line can be used. If a longer duration is expected, a longer line is warranted. Ours is the first study in which the relationship between blood hemoglobin levels and phlebitis has been reported. Because the use of intravascular devices is increasingly common, a more complete knowledge of the factors that influence their acceptance has become essential.

Acute Disease↗
PubMed1999

Nonviolent youth in a violent society: resilience and vulnerability in the country of Colombia.

Despite the ample literature on crime and violence, little research has been done outside English-speaking developed countries. Colombia has one of the highest homicide rates in the world. In order to identify individual factors related to resilience and vulnerability for violence and offending behavior in Colombia, we explored the life histories of 46 young men from high-risk families and compared those who had committed an offense to those who did not (resilient). The findings show that resilient men (compared to offenders) in Colombia have been less exposed to serious life stress, perceive stronger support from their families, narrate their past histories with greater detail and affect, and perceive greater degrees of control and coherence in their lives. The results are consistent with the existing literature and are interpreted within the framework of attachment theory.

Adaptation, Psychological↗
PubMed1998

[Measurement of exhaled nitric oxide in healthy subjects].

BACKGROUND: Endogenously synthesized nitric oxide (NO) is present in exhaled air and its analysis could be used as a tool to monitor inflammatory airway diseases. The objective of the present study was to develop the methodology for the measurement of exhaled NO and to obtain reference values in a group of healthy subjects. SUBJECTS AND METHOD: Exhaled NO was measured in 40 healthy subjects and 22 asthmatic patients using a single breath manoeuvre and a chemiluminescence analyzer. Comparisons of exhaled NO while breathing both, room air and medical air, were performed in 20 subjects. In seven asthmatic patients we evaluated the effect of an inhibitor of NO-synthesis (L-NAME). RESULTS: Mean (SD) exhaled NO in healthy subjects was 18 (13) parts per billion (ppb). Intraindividual variability was 6.5 (6.5%). The concentration of exhaled NO could be overestimated when environmental NO was high (> 80 ppb). Smokers showed lower levels than nonsmokers (10 [7] vs 22 [13] ppb, respectively; p < 0.005), whereas asthmatic patients showed higher exhaled NO levels (62 [31] ppb; p < 0.001). In these patients nebulization of L-NAME induced a progressive fall in exhaled NO (maximal decrease, -68 [15%]; p < 0.01). CONCLUSIONS: The measurement of NO concentration in exhaled air is reproducible, not influenced by the usual levels of environmental NO, and sensible enough to detect changes induced by the administration of a specific inhibitor. Exhaled NO concentration decreases in smokers and increases in asthmatics.

Adult↗
PubMed1998

Testing the measurement properties of the Spanish version of the SF-36 Health Survey among male patients with chronic obstructive pulmonary disease. Quality of Life in COPD Study Group.

The aim of this article is to evaluate the measurement properties of the Spanish version of the SF-36 Health Survey (SF-36). In total, 321 male chronic obstructive pulmonary disease (COPD) patients attending hospital outpatient or primary health clinics were cross-sectionally administered the SF-36, the St. George's Respiratory Questionnaire (SGRQ), and a dyspnea scale. A clinical measure of respiratory function, the proportion of the predicted Forced Expiratory Volume in 1 second (%FEV1) was also obtained. Internal consistency, central tendency, and dispersion statistics of scores were calculated, as well as the percentage of respondents with the highest and lowest scores for each scale and correlations between health status and clinical measures. All patients completed the SF-36 questionnaire, and less than 1% of items were missing. The proportion of patients with the worst possible score (floor effect) ranged from 0.9-20.1% among the different scales. The proportion of patients achieving the best possible score (ceiling effect) ranged from 0-61%. Cronbach's alpha coefficients were above 0.75 except for one scale (Social Functioning, alpha = 0.55). SF-36 scores were moderate to highly correlated with SGRQ scores (coefficients ranged from -.41 to -.79). Correlations were moderate to high with dyspnea and lower but statistically significant with %FEV1. A clear gradient of SF-36 scores was found according to dyspnea levels and disease staging based on %FEV1 impairment, the gradient being more marked for the Physical Functioning, Role-Physical, and General Health scales. Data presented suggest that the Spanish version of the SF-36 is acceptable, valid, and reliable in COPD patients. Although more studies are needed, this version is adequate in international comparisons of health outcomes.

Adult↗
PubMed1998

Interleukin-8 expression in bronchoalveolar lavage cells in the evaluation of alveolitis in idiopathic pulmonary fibrosis.

Interleukin-8 (IL-8) is a neutrophilic chemotactic factor which may have a prominent role in the attraction of neutrophils to the lung in idiopathic pulmonary fibrosis (IPF). The objective of this study was to investigate the usefulness of IL-8 expression in bronchoalveolar lavage (BAL) cells in the evaluation of alveolitis in IPF. We analysed the BAL cell expression of IL-8 by immunocytochemistry in 19 patients with IPF (six smokers, three ex-smokers and ten non-smokers) and in a control group composed of 14 individuals (six smokers, eight non-smokers). In IPF, BAL was performed on both the pulmonary lobe with the most extensive involvement and the one less extensively involved on high-resolution computed tomography (HRCT) scans. The percentages and absolute numbers of BAL IL-8+ macrophages from lobes with the most extensive HRCT scan involvement (36 +/- 6% and (6 +/- 2 x 10(4) ml-1) (SE) and from those less extensively involved [26% +/- 4% and (6 +/- 1) x 10(4) ml-1] were significantly higher with respect to both those from healthy smokers [17% +/- 6% and (7 +/- 4) x 10(4) ml-1] and those from non-smokers [2% +/- 1% and (1 +/- 0.3) x 10(4) ml-1] (P = 0.005 and P = 0.001, respectively), without differences between the two lobes. In contrast, both the proportions and the absolute numbers of BAL neutrophils in IPF were significantly higher in lobes with the most extensively involved HRCT scan in comparison with lobes with the least extensive involvement [13% +/- 3%, (3 +/- 1) x 10(4) ml-1 vs. 8% +/- 2%, (1 +/- 0.3) x 10(4) ml-1, P = 0.05]. Moreover, the numbers of BAL neutrophils, but not those of IL-8+ macrophages, correlated with the extent of total pulmonary HRCT scan abnormalities in the most involved lobe (r = 0.64, P = 0.04). A correlation between neutrophils and IL-8+ cells was not observed. The results of this study suggest that, in IPF, BAL neutrophilia offers a better description of the disease inflammatory process than the expression of IL-8 in BAL cells.

Aged↗
PubMed1998

Prediction equations for forced spirometry from European origin populations. Barcelona Collaborative Group on Reference Values for Pulmonary Function Testing and the Spanish Group of the European Community Respiratory Health Survey.

The objective of this study was the analysis of five sets of reference equations for forced spirometry (Crapo et al., ECSC, Knudson et al., Paoletti et al. and Roca et al.) using measurements of FVC and FEV1 obtained in the European Community Respiratory Health Survey (ECRHS) in Spain. Standardized forced spirometry was measured in 998 non-asthmatic subjects (20-44 years), randomly selected from the general population, participating in the ECRHS in four different Spanish cities. Observed minus predicted values for both FVC and FEV1 were examined for each set of predicted equations. Observed FVC (4448 +/- 980 ml) and FEV1 (3715 +/- 813 ml) showed a good agreement with values predicted by Roca et al. (99% and 101%, respectively). The mean observed minus predicted difference (residual) for FVC and FEV1 were -34 +/- 527 ml and 30 +/- 455 ml, respectively. The regression line between observed and predicted values was not different from the identity line for both FVC and FEV1. These results indicate that reference values obtained by Roca et al. are useful for the assessment of the ventilatory capacity in the general population of Spain. In addition, the study indicates that discrepancies among the reference equations from different authors compared in the present study are unlikely to be due to ethnic differences within European origin populations.

Adult↗
PubMed1998

Prediction equations for plethysmographic lung volumes.

Due to the lack of information of reference values for plethysmographic lung volumes, standardized measurements were carried out on a selected sample of 482 healthy non-smoking volunteers (300 men and 182 women), aged 20-70 years, living in the Barcelona area (Spain). Prediction equations using age, height and body surface area (BSA) as covariates were calculated for the subdivisions of lung volumes [TLC, IC, EVC, FRC, RV and RV/TLC (%)], separately for both sexes. Simple linear equations predicted lung volumes as well as more complex equational models. BSA correction was useful for FRC but not for the other parameters. Our predicted FRC was up to 10% higher (mean 256 ml) than the FRC estimated by other studies using gas dilution techniques, but showed an acceptable agreement with the plethysmographic measurements carried out in an independent sample of 94 healthy non-smokers (42 men and 52 women) from Barcelona using different equipment. The present study provides an internally consistent set of prediction equations for static lung volumes. Differences in predicted FRC between the present study and other reference values obtained using gas dilution measurements should be attributed to the method of measurement.

Adult↗
PubMed1998

Selection of immature pig oocytes for homologous in vitro penetration assays with the brilliant cresyl blue test.

The present study was designed to evaluate the brilliant cresyl blue (BCB) test as a means of selection of immature pig oocytes to improve the performance of the homologous in vitro penetration (hIVP) assay carried out with immature oocytes to assess the penetrating ability of boar spermatozoa. Immature pig oocytes harvested from abattoir ovaries were incubated in 13 microM BCB in phosphate-buffered saline, and selected according to their colour (blue and colourless oocytes) after 90 min incubation at 39 degrees C in 5% CO2 in air. To assess the selection criteria of the BCB test (Experiment 1), the diameter and viability (FDA test) of blue and colourless oocytes were determined. Differences (P<0.01) were found in both mean diameter (113.08 +/- 0.65 microm v. 100.29 +/- 0.96 microm) and the viability rate (100 v. 70.71%) between blue and colourless oocytes. In Experiment 2, the selection effectiveness (healthy oocytes relative to inseminated oocytes) and penetrability (percentage of penetrated oocytes and number of sperm in penetrated oocytes) of unincubated (selected by morphological criteria) and BCB incubated oocytes were evaluated. Blue oocytes showed the best (P<0.001) selection effectiveness and the highest (P<0.01) penetrability. Finally, the effectiveness of the BCB test to reduce interassay variability in the results of hIVP assays was examined (Experiment 3). It was found that more consistent data (P<0.05) of selection effectiveness and percentage of penetrated oocytes were obtained when blue oocytes were used. In summary, these results indicate that the BCB test improves hIVP performance when used to preselect immature oocytes.

Animals↗
PubMed1998

Effect of inverse I:E ratio ventilation on pulmonary gas exchange in acute respiratory distress syndrome.

BACKGROUND: It is not known whether inverse I:E ratio ventilation (IRV) offers any real benefit over conventional mechanical ventilation with positive end-expiratory pressure (CMV-PEEP) at similar levels of end-expiratory pressure. METHODS: The effects of volume-controlled and pressure-controlled IRV (VC-IRV and PC-IRV, respectively) on VA/Q inequality were compared with those of CMV-PEEP at a similar level of end-expiratory pressure and with CMV without PEEP (CMV) in eight patients in the early stages of acute respiratory distress syndrome (ARDS). Respiratory blood gases, inert gases, lung mechanics, and hemodynamics were measured 30 min after the onset of each ventilatory mode. RESULTS: Recruitment of nonventilated, poorly ventilated (or both) but well-perfused alveoli increased the partial pressure of oxygen (PaO2) during CMV-PEEP (+13 mmHg) and IRV-VC (+10 mmHg; P < 0.05) compared with CMV. In contrast, PC-IRV did not affect PaO2 but caused a decrease in PaCO2 (-7 mmHg; P < 0.05). The latter was due to a concomitant decrease in dead space (P < 0.01) and shift to the right of VA/Q distributions. During PC-IRV, the increase in the mean of blood flow distribution (mean Q; P < 0.01) without a change in the dispersion (log SD Q) did not result in an increase in PaO2, probably because it reflected redistribution of blood flow within well-ventilated areas. CONCLUSIONS: Short-term PC-IRV improved carbon dioxide clearance, but the lung became less efficient as an oxygen exchanger. Furthermore, based on mean airway and plateau pressures, the risk of barotrauma was not reduced with this type of ventilation.

Adult↗