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Biomedical subjects

J Mancebo

Publications and source records attributed to J Mancebo.

At least 55 records · Page 3Linked to original sources
PubMed1994

Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation.

Several modalities of ventilatory support have been proposed to gradually withdraw patients from mechanical ventilation, but their respective effects on the outcome of weaning from mechanical ventilation are not known. We conducted a randomized trial in three intensive care units in mechanically ventilated patients who met standard weaning criteria. Those who could not sustain 2 h of spontaneous breathing were randomly assigned to be weaned with T-piece trials, with synchronized intermittent mandatory ventilation (SIMV), or with pressure support ventilation (PSV). Specific criteria for performing tracheal extubation were defined for each modality. The number of patients who could not be separated from the ventilator at 21 d (i.e., who failed to wean) was compared between the groups. Patients in whom tracheal intubation was required in a 48-h period following extubation were also classified as failures. Among 456 mechanically ventilated patients who met weaning criteria, 109 entered into the study (35 with T piece, 43 with SIMV, and 31 with PSV). The three groups were comparable in terms of etiology of disease or characteristics at entry in the study. When all causes for weaning failure were considered, a lower number of failures was found with PSV than with the other two modes, with the difference just reaching the level of significance (23% for PSV, 43% for T piece, 42% for SIMV; p = 0.05). After excluding patients whose weaning was terminated for complications unrelated to the weaning process, the difference became highly significant (8% for PSV versus 33% and 39%, p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Volume-controlled ventilation and pressure-controlled inverse ratio ventilation: a comparison of their effects in ARDS patients.

Volume-controlled ventilation with positive end-expiratory pressure (PEEP) (CPPV) is the conventional ventilatory approach in adult respiratory distress syndrome (ARDS) patients, but some reports suggest that pressure-controlled ventilation with an inverse inspiratory to expiratory ratio (PCIRV) may improve gas exchange in these patients. We analysed the acute effects on gas exchange, lung mechanics and haemodynamics induced by CPPV and PCIRV in ARDS patients. CPPV and PCIRV were applied randomly in ARDS patients. During CPPV, external PEEP was titrated according to the initial inflection point in the static pressure-volume (P-V) curve of the respiratory system, or it was 10 cmH2O when there was no inflection. During PCIRV, external PEEP was not applied, and inspiratory to expiratory (I/E) ratio was inversed until total PEEP was equal to the inflection point in the P-V curve, or it was 10 cmH2O. Respiratory rate, fractional inspiratory oxygen (FIO2), and tidal volume (VT) were kept constant in both modes. Eight ARDS patients were studied prospectively and admitted to a general Intensive Care Unit (ICU) of a University Hospital. Haemodynamic measurements, airflow (V), airway pressure (Paw) and VT were obtained using standard methods. We did not observe any significant change between CPPV and PCIRV with respect to: arterial oxygen tension (PaO2) 117 +/- 12 vs 107 +/- 15 mmHg (16 +/- 2 vs 14 +/- 2 kPa), arterial carbon dioxide tension (PaCO2) 40 +/- 2 vs 39 +/- 2 mmHg (6 +/- 0.3 vs 5 +/- 0.3 kPa), intrapulmonary shunt function (QS/QT) 36 +/- 3 vs 38 +/- 4%, cardiac output (CO) 7.1 +/- 0.7 vs 7 +/- 0.8 l.min-1, and total PEEP 9.7 +/- 0.6 vs 9 +/- 0.3 cmH2O. Oxygen transport and total respiratory system compliance remained unchanged in both modes. Mean Paw was slightly lower during CPPV (17 +/- 1 cmH2O) than during PCIRV (19 +/- 1 cmH2O). PCIRV does not appear to have clinical advantages over CPPV in terms of gas exchange, haemodynamics, or static lung mechanics when using the same total PEEP and minute ventilation.

Adult↗
PubMed1992

[Emphysematous pyelonephritis: a case report and review of the literature].

A case is presented of an E. Coli emphysematous pyelonephritis in a 66 year old female diabetic patient who presented systemic sepsis with positive hemoculture. Diagnosis was obtained thanks to X-ray and the patient had a favorable evolution after left nephrectomy. This is a rare kidney disease (123 described cases) which evolves with necrosis of renal parenchyma and gas formation which frequently expands to the perirenal space and/or to the collector system. It presents a high mortality which can decrease according to the promptness of diagnosis based on X-ray. Thirty eight literature cases of the last decade are reviewed evaluating the efficiency of image diagnostic measures and surgical performance.

Aged↗
PubMed1991

Effects of albuterol inhalation on the work of breathing during weaning from mechanical ventilation.

The work of breathing is a major determinant of the success of weaning from mechanical ventilation. The aim of this study was to assess whether an inhaled bronchodilator could reduce the mechanical load on the respiratory muscles and diminish the work. For this purpose, 15 intubated patients in the process of weaning from mechanical ventilation inhaled the beta 2-agonist bronchodilator albuterol via a spacer device filled with 1 mg of the drug and connected to the endotracheal tube. During spontaneous breathing, the mean work of breathing diminished significantly after albuterol, from 9.35 +/- 1.05 to 8.33 +/- 1.13 J/min (p less than 0.01), and seven patients exhibited a decrease superior or equal to 15%. This decrease resulted from a marked reduction in lung and airway resistance, from 12.0 +/- 1.7 to 9.8 +/- 1.4 cm H2O.L-1.s (p less than 0.05). No significant changes were observed in the breathing pattern, intrinsic PEEP or arterial blood gas measurements after albuterol, and peripheral cardiovascular effects were not significant. In seven patients, we were able to compare the changes that occurred after albuterol in the work of breathing during weaning from mechanical ventilation with the changes in pulmonary function induced by albuterol after extubation, as assessed by the forced oscillation method. A close correlation was found between the two types of change, further indicating that the reduction in the work of breathing was more likely to occur in patients with the largest bronchodilating effect of albuterol at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1991

Constant-flow insufflation prevents arterial oxygen desaturation during endotracheal suctioning.

In mechanically ventilated patients, disconnection from the ventilator and endotracheal suctioning can induce major arterial oxygen desaturation resulting from apnea, changes in inspired oxygen fraction, and decrease in lung volume. The aim of this study was to test the efficacy of a simple method of delivering oxygen and maintaining lung volume during this process. Our study was conducted in two parts. In the first part, constant-flow insufflation of oxygen (CFI) was used in seven patients ventilated for acute respiratory failure (PaO2/FlO2 = 347 +/- 33 mm Hg) as a means of maintaining arterial oxygenation during apnea and disconnection from the ventilator. CFI was administered via a modified endotracheal tube in which small capillaries allowed delivery of a high-velocity jet flow near the tracheal end of the tube during disconnection from the ventilator. In comparison to apnea alone, CFI prevented a fall in arterial oxygen tension (16 +/- 7 mm Hg during CFI versus 117 +/- 27 during apnea, after 90 s of disconnection in the two situations, p less than 0.001), whereas it did not reduce the development of hypercapnia. The efficacy of CFI resulted both from the injection of oxygen into the trachea and from the maintenance of positive alveolar pressure induced by air entrainment (mean 10.4 +/- 1.1 cm H2O), preventing a fall in lung volume usually occurring after disconnection (+338 +/- 88 ml during CFI versus -344 +/- 64 ml during apnea, p less than 0.01). In the second part of the study CFI was used to prevent arterial oxygen desaturation induced by endotracheal suctioning.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Reversal of acute exacerbations of chronic obstructive lung disease by inspiratory assistance with a face mask.

BACKGROUND: Patients with acute exacerbations of chronic obstructive pulmonary disease may require endotracheal intubation with mechanical ventilation. We designed, and here report on the efficacy of, a noninvasive ventilatory-assistance apparatus to provide inspiratory-pressure support by means of a face mask. METHODS: We assessed the short-term (45-minute) physiologic effects of the apparatus in 11 patients with acute exacerbations of chronic obstructive pulmonary disease and evaluated its therapeutic efficacy in 13 such patients (including 3 of the 11 in the physiologic study) who were treated for several days and compared with 13 matched historical-control patients. RESULTS: In the physiologic study, after 45 minutes of inspiratory positive airway pressure by face mask, the mean (+/- SD) arterial pH rose from 7.31 +/- 0.08 to 7.38 +/- 0.07 (P less than 0.01), the partial pressure of carbon dioxide fell from 68 +/- 17 mm Hg to 55 +/- 15 mm Hg (P less than 0.01), and the partial pressure of oxygen rose from 52 +/- 12 mm Hg to 69 +/- 16 mm Hg (P less than 0.05). These changes were accompanied by marked reductions in respiratory rate (from 31 +/- 7 to 21 +/- 9 breaths per minute, P less than 0.01). Only 1 of the 13 patients treated with inspiratory positive airway pressure needed tracheal intubation and mechanical ventilation, as compared with 11 of the 13 historical controls (P less than 0.001). Two patients in each group died. As compared with the controls, the treated patients had a more transient need for ventilatory assistance (3 +/- 1 vs. 12 +/- 11 days, P less than 0.01) and a shorter stay in the intensive care unit (7 +/- 3 vs. 19 +/- 13 days, P less than 0.01). CONCLUSIONS: Inspiratory positive airway pressure delivered by a face mask can obviate the need for conventional mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.

Acute Disease↗
PubMed1990

Intrinsic PEEP on static pressure-volume curves.

The static pressure volume (PV) curve of the total respiratory system is a well established method to assess pulmonary mechanics during respiratory failure. We have tested the impact of auto-PEEP on the PV curve determination in 16 COPD patients. An isovolumic pressure increment (IPI) was found at the beginning of the curve and a close correlation between IPI and auto-PEEP level (r = 0.962) p less than 0.001) was observed. The regression equation was not significantly different from the identity line. We conclude that the appearance of IPI in PV curves is largely determined by auto-PEEP and it is a good estimate of the existing auto PEEP level.

Aged↗
PubMed1990

Endotracheal tube cuff pressure assessment: pitfalls of finger estimation and need for objective measurement.

Estimation of endotracheal (ET) cuff pressure by finger palpation is one of the methods currently used in the clinical setting. We compared the accuracy of this method with instrumental intracuff pressure measurement in tracheal model tests by 20 members of our ICU team. Four different ET tubes at three different pressure levels were examined. Accuracy for the estimated method by finger palpation was 69% for high pressures, 58% for normal pressures, and 73% for low pressures. We observed differences in terms of sensitivity, specificity, and positive predictive power between different tubes reflecting differences in tube characteristics and interobserver variability. We conclude that precise intracuff pressure measurement is mandatory to prevent complications of over- or underinflation.

Clinical Competence↗
PubMed1988

Value of static pulmonary compliance in predicting mortality in patients with acute respiratory failure.

The measurement of static pulmonary compliance by means of pressure-volume curves is an useful tool in the management of patients with acute respiratory failure. On admission to our Intensive Care Unit, we calculated the static pulmonary compliance values from the pressure-volume curve in 55 severe acute respiratory failure patients under mechanical ventilation. A predictive model, based on static pulmonary compliance measured on the deflation of the pressure-volume curve and patients' age, was developed using a function derived by stepwise discriminant analysis. Thirty-six of the 40 patients (90%) in the learning sample and 12 of the 15 patients (80%) in the test sample were correctly classified into survivors or non-survivors. The overall classification demonstrated an accuracy of 88% (48 of 55 patients). We conclude that the value of static pulmonary compliance can be an useful prognostic factor in patients with severe acute respiratory failure.

Adolescent↗
PubMed1988

Accuracy of an indirect carbon dioxide Fick method in determination of the cardiac output in critically ill mechanically ventilated patients.

We evaluated the accuracy of an indirect CO2 Fick method for measuring cardiac output in 30 critically ill mechanically ventilated patients. When the Fick principle was applied to CO2 using estimated PaCO2, the cardiac output obtained underestimated the thermodilution technique showing a lack of accuracy. However, there was a significant correlation between thermodilution and CO2 rebreathing methods using measured (r = 0.92; p less than 0.001) and estimated (r = 0.60; p less than 0.01) arterial PCO2. The regression equation using measured arterial PCO2 was y = 0.59 + 0.91x, and for estimated arterial PCO2 was y = 1.7 + 0.33x. The results suggest that the CO2 rebreathing method using measured arterial PCO2 may be useful to determine cardiac output in those seriously ill patients on artificial ventilation not requiring right heart catheterization.

Adult↗
PubMed1987

A clinical study of the adult respiratory distress syndrome.

The adult respiratory distress syndrome (ARDS) is a syndrome of diffuse lung injury with a high mortality rate. We evaluated retrospectively 35 adult patients with ARDS. Their overall mortality rate was 69% and was related to their age (32 +/- 14 yr in survivors and 54 +/- 15 yr in nonsurvivors; p less than .001) and to the number of complications during their illness (1.4 complications in survivors, 2.6 in nonsurvivors; p less than .005). The ARDS patients, due to an infectious etiology, incurred a 75% mortality rate, while those with a noninfectious etiology of ARDS had a 55% mortality rate (nonsignificant). Neither a simplified acute physiology score nor a respiratory failure severity index was significantly different between survivors and nonsurvivors on admission. The mean PEEP level on admission in survivors was 8.1 +/- 4.6 cm H2O and in nonsurvivors 3.7 +/- 3.9 cm H2O (p less than .025). We conclude that the age of the patients and superimposed multiple system organ failure are probably related with the still high mortality rate of this syndrome.

Acute Kidney Injury↗
PubMed1987

Effect of PEEP on the arterial minus end-tidal carbon dioxide gradient.

The effect of PEEP on the arterial minus end-tidal carbon dioxide gradient (PaCO2-PetCO2) was evaluated in 13 adult patients with acute respiratory failure. The morphologic study of the pressure-volume (P-V) curves allowed separation of the patients into two groups: group 1 (n = 7) with initial inflection point in the (P-V) curve, and group 2 without inflection point. We hypothesized that the profile of the PaCO2-PetCO2 gradient would indicate an appropriate PEEP level only in patients with recruitable air spaces. We ventilated group 1 patients with zero end expiratory pressure (ZEEP), PEEP corresponding to inflection point pressure (PEEPPi) and PEEP5 cm H2O above PEEPPi, and group 2 patients with ZEEP, 6 cm H2O PEEP and 12 cm H2O PEEP. The PaCO2-PetCO2 gradient changed significantly in group 1 (ZEEP: 13.59 mm Hg; PEEPPi: 8.33 mm Hg; PEEPPi + 5 cm H2O: 10.54 mm Hg), but not in group 2 (ZEEP: 14.15 mm Hg; PEEP 6 cm H2O: 14.20 mm Hg; PEEP 12 cm H2O: 16.53 mm Hg). Our results show that the PaCO2-PetCO2 gradient may be useful in selecting a PEEP level which produces alveolar recruitment, but only in those patients with initial inflection point in the P-V curve.

Adult↗