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Results for “POSITIVE-PRESSURE RESPIRATION”

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At least 577 records · Page 32Linked to original sources
PubMed1977

High-frequency positive-pressure ventilation (HFPPV) in neonates and infants during neuroleptal analgesia and routine plastic surgery, and in postoperative management.

The low pulmonary compliance, the high airway resistance and the "rapid" breathing pattern of neonatal and paediatric patients make it necessary to design special ventilators to match the pulmonary physiology of infants. A ventilator system which also in small children has a negligible compression volume was evaluated in a lung model and during repair of cleft lip and palate in 16 patients under general anaesthesia and in two other infants during other operations. High-frequency positive-pressure ventilation (HFPPV) was given with an insufflation frequency (f) of 60 per min and a relative insufflation time (t%) of 32%. In addition, two neonates treated postoperatively with HFPPV are reported. Despite the "open" character of the ventilator system both intra- and postoperative ventilation were uneventful in all patients. The arterial oxygenation was good in all cases, as judged from clinical signs or blood gas analyses. Postoperative ventilation required conventional clinical observation and intermittent analyses of blood. HFPPV has been shown to depress, or abolish, spontaneous respiration via reflex mechanisms. In all patients in this investigation respiratory movements were absent at normo- or slight hyperventilation during HFPPV.

Adult↗
PubMed1978

[Surgical treatment of the flail chest (author's transl)].

Six patients with traumatic flail chest underwent surgical stabilization using a procedure introduced by Brunner, Hoffmeister and Koncz (2). Compared with internal stabilization by intermittend positive pressure respiration (IPPR), there are some advantages: Time of artificial respiration is shortened, early mobilization is possible, nursing is easier. The procedure is simple to do and is indicated in those patients, in whom longterm artificial respiration is not necessary for other reasons.

Adult↗
PubMed1978

Long term prognosis of infants with severe idiopathic respiratory distress syndrome. II. Cardio-pulmonary outcome.

75 out of 77 children surviving IRDS with the aid of intermittent positive pressure ventilation have been followed up by age 2.6-7.6 years together with 68 matched controls. The morbidity of lower respiratory tract illnesses was significantly higher in IRDS survivors than in controls affecting a total of 48%, half whom were admitted to hospital on at least on occasion. Only 3 IRDS survivors had pneumonias beyound their third year, however. One child suffered from a moderate stridor due to a partial laryngeal stenosis and one from some dyspnoea at function caused by broncho-pulmonary dysplasia. Thoracic X-ray changes were found significantly more often and more marked in IRDS survivors but on the whole the changes were discrete. Neither the occurrence of pneumonia nor X-ray changes in the IRDS survivors were statistically relatable to a number of neonatal or therapeutical characteristics. Measurements of heart volume, respiratory frequency, oxygen saturation and acid-base values did not differ between the groups. Ventilated IRDS survivors, even with some degree of radiographic demonstrable residua, thus seem to have a good long-term prognosis with regard to lung function, irrespective of a preliminary high morbidity of lower respiratory tract illnesses.

Acid-Base Equilibrium↗
PubMed1978

Lung tissue guanosine 3',5'-monophosphate: effects of ventilation and anesthesia.

In vivo levels of guanosine 3',5'-cyclic monophosphate (cGMP) in rat lung were measured by radioimmunoassay. The basal levels of this agent were found to change depending on the method of killing or anesthesia used. Lowest values were found after microwave irradiation to the head (10.2 fmol/mg wet wt). Values after pentobarbitol anesthesia, with or without atropine, were significantly higher (19-24 fmol/mg). In animals anesthetized with pentobarbital and ventilated at pressures of 7 cmH2O with no end-expiratory pressure, lung cGMP was 42-49 fmol/mg. Ventilation at higher pressures resulted in much higher levels of cGMP (20 cmH2O, 105 fmol/mg; 30 cmH2O, 233 fmol/mg). The response of cGMP to ventilation was not blocked by pretreatment of the animals with atropine. High-pressure ventilation was without effect on lung adenosine 3',5'-cyclic monophosphate.

Animals↗
PubMed1978

Passive expiration as a test of lung function.

Twenty-five normal subjects, 14 non-smokers and 11 smokers, passively expired into a spirometer after a maximal active inspiration, and after a passive inflation of the chest by a pressure cycled intermittent positive-pressure breathing (IPPB) machine. Acceptable passive expirations could be performed by all subjects after a passive inspiration but by only 12 after an active inspiration. Expired volume was found to change exponentially with time (r greater than 0.98), and the time constant of passive expiration (Tp) was obtained. There was no significant difference between the smokers and non-smokers in age, sex, forced vital capacity, FEV1 FEV1/FVC%, maximum mid-expiratory flow rate, maximum expiratory flow at 50% and 25% of the vital capacity, or the magnitude of the fall in the dynamic compliance with increasing frequency of breathing (Cdyn/f). Tp in smokers (1.06 +/- 0.47 SD) was significantly longer than in the non-smokers (0.65 +/- 0.25 SD P less than 0.02). Tp had a significant correlation with Cdyn/f(Tp = 0.6 + 161.81 Cdyn/f +/- 0.38 SE, r = 0.49, P less than 0.02). We conclude that satisfactory passive expiratory spirograms can be easily obtained after a mechanically assisted passive inspiration. Tp thus obtained is determined by the intrinsic properties of the respiratory system (lung plus thorax), and is significantly prolonged in smokers compared with non-smokers when other studies of pulmonary function including frequency dependence of compliance are unchanged.

Adult↗
PubMed1975

Assisted ventilation in infants with meconium aspiration syndrome.

In a retrospective analysis of infants born with meconium staining over an 18-month period at Cook County Hospital, 32 infants met two of the three criteria for the diagnosis of meconium aspiration syndrome: (1) history of meconium in the oropharynx or trachea; (2) clinical evidence of respiratory distress; and (3) x-ray evidence of aspiration pneumonia. Seventeen infants developed respiratory failure; nine of these infants died. One infant without respiratory failure died of sepsis. Analysis of sequential arterial blood pH and gas tension showed that nonsurviving infants had persistently high PCO2 and A-a gradient in spite of initiation of assisted ventilation. These changes seem to be related to severe right-to-left shunting and ventilation perfusion abnormalities. The data further suggest that asphyxia and acidosis occur well before the infant is born and that intrapartum monitoring to recognize fetal asphyxia may help in improving morbidity and mortality from meconium aspiration syndrome.

Blood Gas Analysis↗
PubMed1977

Effect of different respirator adjustments on central haemodynamics in open-heart surgery patients.

Changes in cardiac index (CI) mean pulmonary artery pressure (PAP), mean pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), and pulmonary artery vascular resistance (PVR), associated with spontaneous respiration (SR) and two different types of intermittent positive pressure ventilation (IPPPV and IPNPV) were studied in a total of 17 patients undergoing aortic valve replacement or myocardial revascularization. Swan-Ganz thermodilution pulmonary artery cardiac output catheters were used and the aim was to determine: whether postoperative cardiac output may paradoxically be greater during IPPPV than during IPNPV or SR; whether the use of "negative" pressure in the expiratory phase during controlled ventilation may be responsible for bringing about the central haemodynamic conditions prevailing during spontaneous respiration; and whether, in weaning from postoperative IPPPV to SR, there is a risk of pulmonary congestion as a consequence of possible autotransfusion. IPPPV connected with anaesthesia induction caused a highly significant deterioration central haemodynamics. The use of positive end-expiratory pressure (PEEP) is not to be recommended for such patients at this stage. On the first postoperative day, the mean CI was lower during IPPPV than during IPNPV (P less than 0.1) or during SR (P less than 0.05). The changes observed in CI, were, however, so slight that the authors consider the routine use of PEEP to be beneficial during controlled ventilation following major open-heart surgery. In some patients, the CI was paradoxically higher during IPPPV than during IPNPV or SR. The mean CI was nearly the same during IPNPV (3.32) as during SR (3.38). However, PAP, PCWP and PVR values were significantly higher during SR than during IPNPV. Thus, according to this study, the use of "negative" end-expiratory pressure during controlled ventilation did not in these patients produce central pressure conditions corresponding to spontaneous respiration. The present study supports the finding that in weaning from controlled ventilation with PEEP to SR there is a danger of pulmonary congestion. This could be predicted by measurement of pulmonary wedge pressure, but not by measurement of central venous pressure.

Adult↗
PubMed1978

Evaluation of criteria for discontinuing mechanical ventilatory support.

Thirty-three patients who required short-term postoperative mechanical ventilatory support were studied to compare different criteria established to initiate weaning from mechanical ventilation. Intermittent mandatory ventilation criteria (i.e., decreasing mechanical respirator rate as long as the arterial (pHa) remains above 7.35) and conventional criteria (ie, vital capacity greater than 15 ml/kg and peak negative pressure greater than 20 cm H2O) were compared to determine which would more rapidly predict a patient's ability to sustain total spontaneous respiration. All patients were eventually weaned from mechanical ventilation and had their tracheas extubated. Twenty-one patients maintained a pHa of greater than 7.35 during total spontaneous ventilation before they would, or could, meet conventional criteria for initiating a trial of spontaneous respiration (P less than .001). Seven patients simultaneously met both criteria for maintaining total spontaneous ventilation and the remaining five patients met conventional criteria before intermittent mandatory ventilation criteria. In the latter group, the pHa decreased below 7.35 during spontaneous respiration but in only one patient did it fall below 7.30. Our findings suggest that a patient's ability to maintain a pHa of greater than 7.35 while decreasing the frequency of mechanical ventilator breaths is more accurate than peak negative pressure and vital capacity for predicting ability to sustan adequate spontaneous respiration.

Adolescent↗
PubMed1977

[Treatment of flail chest from the general surgical view. Experience with 20 cases].

Flail chest is a serious complication of multiple fractures of the ribs that needs immediate management in order to avoid its disastrous respiratory and circulatory consequences. The authors present their experience with 20 cases of flail chest injury and discuss especially some practical aspects of its treatment. Skeletal traction was used frequently to stabilize the chest wall, while intermittent positive pressure respiration was reserved only for patients with uncompensated respiratory disturbances. The authors urge that a well-organized surgical unit should be able to provide appropriate management in such cases, since most of these patients have multiple injuries that need general surgical together with more specialized treatment.

Adolescent↗
PubMed1978

Amelioration of bronchopulmonary dysplasia after vitamin E administration. A preliminary report.

We studied the effect of vitamin E on the development of bronchopulmonary dysplasis in neonates with respiratory-distress syndrome. Twenty infants received vitamin E administered intramuscularly during the acute phase of the syndrome, and 20 infants served as controls. Administration of vitamin E significantly increased the serum vitamin E concentration. Nine vitamin-treated and 13 control patients required supplemental oxygen for longer than 250 hours; all were treated with positive-pressure ventilation and endotracheal continuous distending airway pressure. Six of those 13 controls had x-ray changes consistent with bronchopulmonary dysplasia, and four died. None of the nine vitamin-treated patients had changes characteristic of bronchopulmonary dysplasia (P = 0.046), and all survived. Administration of vitamin E during the acute phase of the respiratory-distress syndrome appears to modify the development of bronchopulmonary dysplasis.

Bronchial Diseases↗
PubMed1977

Body position and mode of ventilation influences arterial pH, oxygen, and carbon dioxide tensions in halothane-anesthetized horses.

Effects of body position and type of ventilation were determined on arterial blood gases (PaO2, PaCO2) and pH during and immediately following clinical halothane anesthesia in 36 young, physically conditioned horses. Horses in dorsal recumbency had a lower PaO2 than did similarly breathing horses in a lateral position. Predictably controlled positive-pressure ventilation inproved arterial oxygenation and permitted maintenance of a normal PaCO2. Most horses, regardless of type of ventilation and operative body positioning, were hypoxemic in the immediate postanesthetic period.

Anesthesia, Inhalation↗
PubMed1977

[Two-phase respiration of apnoeic newborn, basic research and clinical value (author's transl)].

Studies on fetal human and calf lungs proved an 1: 2,5 increase rate of the transpulmonary blood-flow after inflation of the alveolar spaces. The extent of the inflation depends on the function pressure X time. Based on the rupture rate of the pulmonary tissue, the factor pressure is limited to 20-30 ch H2O. Consequently the inflation only can be obtained by increasing the factor time. Conditional on the flow resistance in the variably calibrated branches of the pulmonary system, the maximal pressure of 30 cm H2O has to act repeated continuously at least 10 seconds over an endotracheal tubus. Only then even the periphere alveoles will fully be inflated (phase I equals monotone inflation phase). An intermittend pressure breathing of maximal plus 30 cm H2O respectively-30 cm H2O will be supporting. After the total inflation short pressure waves of plus 30 cm H2O in physiological frequency (equals 30/minute) will do for further ventilation of the alveoles (phase II equals rhythmical ventilation phase).

Asphyxia Neonatorum↗