Showing papers on "Hypoventilation published in 1990"
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TL;DR: All 34 patients who were not dependent on ventilatory support 24 hours a day demonstrated significant improvement and in most cases normalization of ABG when off aid, and NIPPV can be an effective alternative to TIPPV, body ventilators, or oxygen therapy.
250 citations
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TL;DR: Sleep studies should be performed on post-polio patients with excessive daytime sleepiness and respiratory complaints, including individuals already on respiratory assistance such as rocking beds who have features of respiratory failure who can be treated effectively with long-term nasal mechanical ventilation.
80 citations
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TL;DR: Despite very high levels of PCO2 and low pH, the only pathophysiologic change found was temporary depression of neurologic function manifested by stupor or coma during the supercarbia period.
Abstract: Supercarbia (Pco2 >150 torr) may result in a number of pathophysiologic conditions in experimental models and in humans. We report the clinical course and outcome after supercarbia secondary to hypoventilation in five children. Supercarbia resulted from severe airway obstruction in four children and
69 citations
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TL;DR: The reduced ventilatory drive appears to be due to an altered neural control system that may cause episodic life-threatening hypoventilation occurring especially in relation to surgery, sedation, or intercurrent infection.
Abstract: Three patients with mitochondrial myopathies and progressive external ophthalmoplegia had repeated episodes of respiratory failure requiring assisted ventilation. Studies in these patients and asymptomatic family members, as well as a sporadic case of Kearns-Sayre syndrome, demonstrated markedly depressed ventilatory drive responses to hypoxia. In 2 patients, there was also decreased drive to hypercapnia. The reduced ventilatory drive appears to be due to an altered neural control system that may cause episodic life-threatening hypoventilation occurring especially in relation to surgery, sedation, or intercurrent infection.
59 citations
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TL;DR: It is concluded that noninvasive intermittent ventilatory assistance effectively reverses hypoventilation and symptoms in patients with late-stage Duchenne muscular dystrophy, but pulmonary function continues to deteriorate necessitating longer periods of ventilation, and often tracheostomy, within a few years.
58 citations
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39 citations
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TL;DR: This work focuses on the management of chronic hypoventilation in Chest D A Strumpf, R P Millman and N S Hill, the official journal of the American College of Chest Physicians.
36 citations
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TL;DR: In this article, the authors found that moderate hypercapnia powerfully depresses flexor withdrawal responses to noxious stimuli, by a mechanism involving release of endogenous opioids but not systemic catecholamines, which may account in part for the elevation in pain threshold during hypoventilation.
31 citations
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TL;DR: Reduced forced expiratory volume in 1 s to vital capacity ratios (FEV1/VC) and a higher proportion of cigarette smokers in the group of patients with CMS compared with control subjects suggested that at least some patients had mild airway obstructive lung disease.
Abstract: Persons with chronic mountain sickness (CMS) hypoventilate and are more hypoxemic than normal individuals, but the cause of the hypoventilation is unclear. Studies of 14 patients with CMS and 11 healthy age-matched control subjects residing in Lhasa, Tibet, China (3,658 m) were conducted to test the hypothesis that hypoventilation, blunted hypoxic ventilatory responsiveness (HVR), and hypoxic ventilatory depression of CMS were due to increased endogenous opioid production. Patients with CMS compared with control subjects exhibited hypoventilation (end-tidal carbon dioxide pressure [PETCO2] = 36.6 +/- 1.0 versus 31.5 +/- 0.5 mm Hg, p less than 0.05), lower tidal volume (VT = 0.54 +/- 0.02 versus 0.61 +/- 0.02 ml BTPS, p less than 0.05), blunted HVR (shape parameter A = 17 +/- 8 versus 114 +/- 22 mm Hg/L BTPS/min, p less than 0.05), and a depressant effect of ambient hypoxia on ventilation (delta PETCO2 with acute hyperoxia = -3.5 +/- 0.5 versus -1.0 +/- 0.6 mm Hg, p less than 0.05). Reduced forced expiratory volume in 1 s to vital capacity ratios (FEV1/VC) and a higher proportion of cigarette smokers in the group of patients with CMS compared with control subjects suggested that at least some patients with CMS had mild airway obstructive lung disease. Naloxone infusion (0.14 mg/kg) to six patients with CMS did not change resting VT, PETCO2, HVR, or SaO2.(ABSTRACT TRUNCATED AT 250 WORDS)
25 citations
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TL;DR: In patients with Ondine's curse and Hirschsprung's disease in whom the aganglionosis can be effectively managed, diaphragm pacing may lead to independence from mechanical ventilation and prolongation of life of an acceptable quality.
Abstract: Hirschsprung's disease can be associated with other congenital abnormalities, some of which are neural in origin. A rare association is with congenital failure of automatic control of respiration—central hypoventilation syndrome, sleep apnoea or Ondine's curse. Patients with this combination tend to have a short life expectancy. Diaphragmatic pacing by electrophrenic stimulation has proven useful in management of patients with central hypoventilation. Three children, two females and one male, with this combination are described. The male child, who had total intestinal aganglionosis, died at the age of one month despite an ileostomy and nocturnal mechanical ventilation. The two females had aganglionosis more typical of Hirschsprung's disease, one requiring colostomy. At the ages of 2 and 6 years, respectively, phrenic nerve stimulators were implanted. Both girls remain independant of nocturnal, mechanical ventilation two and three years after commencement of diaphragm pacing. In patients with Ondine's cur...
21 citations
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TL;DR: Loss of the descending wakefulness influence leads to loss of motor compensation that results in a rise in upper airway resistance, obstructive sleep apnea or hypoventilation in patients with kyphoskoliosis or thoracic neuromuscular disorders.
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TL;DR: It is concluded that cardiovascular responses to verapamil, nifedipine and probably other calcium antagonists are altered in the presence of blood gas abnormalities.
Abstract: 1. The influence of hypoventilation or hyperventilation on blood pressure and pulse rate responses to verapamil and nifedipine was studied in chloralose-anaesthetized rats. 2. Artificial ventilation with room air at a fixed volume of 10 ml kg-1 successfully induced combinations of hypoxaemia, hypercarbia and acidosis at a ventilator rate of 37 strokes min-1 and of hyperoxaemia, hypocarbia and alkalosis at 160 strokes min-1. 3. Hypoventilation caused significant decreases in both the blood pressure and pulse rate, whereas hyperventilation produced significant increases in these parameters. 4. In the controls, intravenous injections of graded doses of either verapamil or nifedipine caused dose-dependent decreases in mean blood pressure. The effects on pulse rate were not marked. 5. The hypotensive effects of verapamil were significantly more intense in hyperventilated rats, whereas those of nifedipine were significantly less pronounced in hypoventilated animals. The hypoventilated rats exhibited a significant dose-dependent decrease in pulse rate in response to verapamil administration. 6. It is concluded that cardiovascular responses to verapamil, nifedipine and probably other calcium antagonists are altered in the presence of blood gas abnormalities.
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TL;DR: It is concluded that mechanical ventilation in the acute stage of epidural bleeding may be of clinical value and due to the particular form of the time/pressure course, in epidural bleed, this treatment may have considerable therapeutic value.
Abstract: During an experimentally induced aggressive epidural bleed the effect on outcome of haematoma volume, cerebral perfusion pressures, intracranial pressure gradients and ventilation were examined in a swine model. Two groups of experiments were performed using either spontaneous ventilation (group 1, n=6) or mechanical ventilation for 1 hour (group 2, n=7). The preparations were otherwise identical. An animal was considered to have succumbed when the EEG became irreversibly isoelectric within a total follow-up time of 80 minutes. Mechanical ventilation had a marked effect on survival. All spontaneously ventilated animals succumbed, 4 of them in less than 60 minutes, the remaining 2 between 60 and 80 minutes after the start of bleeding. All mechanically ventilated animals survived for the 60 minutes while the ventilator was connected. Following disconnection 2 animals started to breathe spontaneously and survived the final 20 minutes of the 80 minutes of the follow-up time. The remaining 5 succumbed following apnoea. The size of haematoma did not differ significantly between the groups. Two additional factors, hypoventilation and a secondary rise in supratentorial pressure, contributed to a lethal outcome. Hypoventilation was an inevitable precursor of the isoelectric EEG. There was a close correlation between the development of hypoventilation and intracranial herniation. A secondary rise in supratentorial pressure, unrelated to ventilation, was seen after cessation of bleeding in 8/13 cases. It was associated with a falling supratentorial perfusion pressure and EEG attenuation, suggesting a secondary intracranial expansion, possibly due to oedema, hydrocephalus or both. It is concluded that mechanical ventilation in the acute stage of epidural bleeding may be of clinical value. Due to the particular form of the time/pressure course, in epidural bleeding, this treatment may have considerable therapeutic value.
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TL;DR: A 30-year-old man for whom Plaquenil had been prescribed for rheumatoid arthritis, and who had taken 4 g orally to end his life, survived the intoxication and is now under psychiatric treatment.
Abstract: We treated a 30-year-old man for whom Plaquenil (hydroxychloroquine) had been prescribed for rheumatoid arthritis, and who had taken 4 g orally to end his life. Symptoms of severe intoxication due to (hydroxy)chloroquine are rapid onset of hypoventilation, cardiovascular collapse with bradycardia, peripheral vasodilation, arrhythmias and convulsions. The lethal dose of chloroquine has been estimated at 3-5 g in adults and at 0.75-I g in young children. Acute intoxication should be treated with aspiration of gastric contents, artificial ventilation in case of hypoventilation and intravenous or intratracheal dopamine, noradrenaline or adrenaline in case of cardiovascular depression and peripheral vasodilation. Arrhythmias and convulsions should be treated symptomatically. The patient in our case survived the intoxication and is now under psychiatric treatment.
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TL;DR: Pressure support appears to be more suitable for patients with adequate drive but poor respiratory effort in conditions giving rise to low vital capacities and tidal volumes, while IMV is commonly used in patients with an inadequate respiratory drive but who can generate adequate tidal volumes.
Abstract: Choosing ventilation mode and settings IPPV remains the mainstay of ventilation therapy for patients with no spontaneous respiratory activity. These will be patients undergoing routine anaesthesia, comatose patients or sedated patients with respiratory failure. The use of PEEP is indicated when oxygenation is inadequate or in order to reduce high F iO 2 levels. The level of PEEP applied is chosen as a compromise between achieving satisfactory arterial blood gases and minimizing cardiovascular depression. Ventilator rates are adjusted during IPPV to achieve the required minute ventilation with given tidal volumes. Limiting factors include the absolute values of expiratory times in relation to the RC constant for the individual respiratory system, and the airway pressures produced with the given tidal volumes. In severe cases of asthma, controlled hypoventilation may be acceptable in order to allow full deflation of the lungs and avoid excessively high airway pressures. If full deflation of the lungs is not allowed, an ‘auto-PEEP' effect is produced as with the use of inverse ratio IPPV or with high ventilation frequencies as in HFV. Improved oxygenation in acute severe asthma with reduced hyperinflation and pleateau airway pressure, has been reported with the use of high inspiratory flows and low tidal volumes, in order to maximize expiratory times at a constant respiratory rate (Tuxen and Lane, 1987). Severe unilateral lung problems or mechanical mismatch may require the use of differential lung ventilation, possibly with mixed modes, in order to achieve satisfactory gas exchange. Such conditions include the occurrence of a unilateral bronchopleural fistula, a large unilateral bulla or severe unilateral collapse or consolidation. HFPPV or HFJV techniques in the past have been applied in extremecases of lung pathology where refractory hypoxaemia is a problem, or gross leaks from bronchopleural fistula have made IPPV ineffective. Certainly in cases of upper airway disruption the ability of HFJV to maintain ventilation in the absence of a sealed delivery circuit via a catheters makes it a technique of choice. The ability of HFJV to deliver high minute volumes also enables it to cope in the presence of large shunts. However, in cases of severe hypoxaemia, although HFV modes may offer improved oxygenation by promoting non-tidal mechanisms of gas transport at the higher frequencies (e.g. HFOV), or by taking advantage of grossly altered lung frequency responses, the consistent superiority of any one mode or combined mode has yet to be proven. Mixed spontaneous and mechanical modes of ventilation find their mainapplication in patients with spontaneous respiratory activity or in weaning from ventilation. IMV is commonly used in patients with an inadequate respiratory drive but who can generate adequate tidal volumes. While MMV may be more suitable for patients with variable respiratory drive, this mode still requires further evaluation. Pressure support appears to be more suitable for patients with adequate drive but poor respiratory effort, i.e. in conditions giving rise to low vital capacities and tidal volumes. During weaning from mechanical ventilation, the choice of mode and CPAP or sPEEP levels has to be made in a context that may not necessarily place P aO 2 or P aCO 2 level as the primary criteria. The mechanical ability of the patient to cope with the work of breathing may be a major problem and a compromise between gas exchange and work of breathing capability may have to be reached. Additional factors such as nutrition and patient psychology can also become important during prolonged weaning. CPAP and sPEEP techniques may also have a prophylactic role enabling patients with moderate respiratory dysfunction to avoid endotracheal intubation and/or mechanical ventilation. Accurate and adequate monitoring, including the measurement of respiratory mechanics, is essential for the optimum choice and adjustment of ventilation therapy.
25 Jun 1990
TL;DR: In this article, the authors investigated the effect of cold exposure on male Holstein calves 1-3 months old and found that respiratory frequency decreased 29% while tidal volume increased 35%.
Abstract: : Possible thermoregulatory benefits of cold-induced changes in breathing pattern (hypoventilation) and the mechanism(s) by which cold stimulates a change in breathing pattern were investigated in male Holstein calves 1-3 months old. Effects of ambient temperatures (Ta) between 4 and 18 C on ventilatory parameters and respiratory heat loss were determined in 4 calves. As Ta decreased, respiratory frequency decreased 29% while tidal volume increased 35%. Total ventilation (VE) did not change significantly, but the ventilatory equivalent for O2 decreased with decreasing Ta. Calves were capable of conserving respiratory heat during cold exposure by decreasing expired air temperature and by decreasing dead space ventilation while increasing O2 extraction. hypoventilation is suggested as a mode of heat conservation in cold environments in animals which use panting as a means of increasing evaporative heat loss. The effect of cold-induced hypoventilation on pulmonary particle deposition was investigated in 10 calves. Deposition of nasally-instilled fluorescent Pasteurella haemolytica was significantly higher for cold-exposed calves. It is speculated that the cold-induced respiratory pattern change was responsible. Nasal mucus velocity (NMV) was measured in four unanesthetized calves at Ta = 2-4 C and Ta = 16-18 C, using a radiographic tracking technique. NMV was 24% lower during cold exposure. It is possible that cold-exposure decreases tracheal mucociliary clearance rate. It is speculated that mucociliary clearance rate may be partially genetically determined. Cold-induced decreases in particle clearance, and increases in deposition, may predispose calves to respiratory infection. Keyword: Dissertations.
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TL;DR: In patients with bronchial asthma, when blood pressure in the pulmonary artery is measured, very often hypertension is registered, and it is probable that its origin is in an allergic vasoconstriction of the pulmonary arteries, occurring simultaneously with the well known bronchoconStriction.
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TL;DR: In eight anesthetized mongrel dogs with thiopental, diazepam and pancuronium bromide, ECMO with arterio-venous shunt was performed under hypoventilation for 24 hours and there were no abnormalities in cardiovascular and other systems during ECMO.
Abstract: In eight anesthetized mongrel dogs with thiopental, diazepam and pancuronium bromide, ECMO with arterio-venous shunt was performed under hypoventilation for 24 hours. The blood flow through the ECMO which was connected between the femoral artery and vein was approximately 40% of the cardiac output. Hypoventilation was induced to decrease PaO2 to around 40mmHg and increase PaCO2 to around 80 mmHg. The ECMO improved the abnormal parameters, which were induced by the hypoventilation, to almost normal range (PaO2 80mmHg, PaCO2 30mmHg) for 24 hours. Furthermore, there were no abnormalities in cardiovascular and other systems during ECMO.
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TL;DR: The authors tested the monitor on eight anesthetized patients and found the apnea alarm to be effective and efficient and the ventilation alarm index, a system specific to this monitor, detected hypoventilation and also differentiated between irrelevant body movements and apnea.
Abstract: The Atlas AR-8800, an impedance pneumograph respiratory monitor, is claimed to detect both apnea and hypoventilation. The authors tested the monitor on eight anesthetized patients and found the apnea alarm to be effective and efficient. In addition, the ventilation alarm index, a system specific to this monitor, detected hypoventilation and also differentiated between irrelevant body movements and apnea.
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TL;DR: In both groups even when it was possible to maintain oxygenation capacity by conducting mechanical ventilation against severe respiratory failure, what can be said about the prognosis is that it depended totally on the improvement of cardiac function.
Abstract: Respiratory failure accompanied by cardiac failure occurs mostly due to decreased PaO2. However, sometimes we encounter patients with cardiac failure having on increase of PaCO2, who develop CO2 narcosis in the ICU. In this study we evaluated hypoventilation respiratory failure in patients with cardiac failure. Seventy-six patients with both respiratory failure and cardiac failure caused by intrinsic heart disease, who required mechanical ventilation in the ICU were studied. The patients were divided into 2 groups; hypoxic respiratory failure group (n = 53) and hypoventilation respiratory failure group (n = 23). Blood gas analysis and cardiovascular hemodynamics including arterial blood pressure, heart rate and Swan-Ganz catheter findings were performed before, during and after mechanical ventilation in each patient. Mortality rate and its relation to hemodynamic variables were also evaluated in each group. In both groups even when it was possible to maintain oxygenation capacity by conducting mechanical ventilation against severe respiratory failure, what can be said about the prognosis is that it depended totally on the improvement of cardiac function. The mechanism by which hypoxemia is displayed due to cardiogenic pulmonary edema is already well known, but in regard to the mechanism of hypercapnia in cases with hypersensitivity of the airways it is thought that through induction of cardiogenic pulmonary edema bronchial spasms is induced, and this causes hypercapnia. However, it is also possible to consider cardiac asthma as the cause. Among respiratory failure cases due to cardiogenic pulmonary edema that occurs in association with heart failure, there is both hypoxic respiratory failure as well as hypoventilation respiratory failure.(ABSTRACT TRUNCATED AT 250 WORDS)
01 Jan 1990
TL;DR: It is concluded that mechanical ventilation in the acute stage of epidural bleeding may be of clinical value and due to the particular form of the time/pressure course, in epidural bleed, this treatment may have considerable therapeutic value.
Abstract: Summary During an experimentally induced aggressive epidural bleed the effect on outcome of haematoma volume, cerebral perfusion pressures, intracranial pressure gradients and ventilation were examined in a swine model. Two groups of experiments were performed using either spontaneous ventilation (group 1, n = 6) or mechanical ventilation for 1 hour (group 2, n = 7). The preparations were otherwise identical. An animal was considered to have succumbed when the EEG became irreversibly isoelectric within a total follow-up time of 80 minutes. Mechanical ventilation had a marked effect on survival. All spontaneously ventilated animals succumbed, 4 of them in less than 60 minutes, the remaining 2 between 60 and 80 minutes after the start of bleeding. All mechanically ventilated animals survived for the 60 minutes while the ventilator was connected. Following disconnection 2 animals started to breathe spontaneously and survived the final 20 minutes of the 80 minutes of the follow-up time. The remaining 5 succumbed following apnoea. The size of haematoma did not differ significantly between the groups. Two additional factors, hypoventilation and a secondary rise in supratentorial pressure, contributed to a lethal outcome. Hypoventilation was an inevitable precursor of the isoelectric EEG. There was a close correlation between the development of hypoventilation and intracranial herniation. A secondary rise in supratentorial pressure, unrelated to ventilation, was seen after cessation of bleeding in 8/13 cases. It was associated with a falling supratentorial perfusion pressure and EEG attenuation, suggesting a secondary intracranial expansion, possibly due to oedema, hydrocephalus or both. It is concluded that mechanical ventilation in the acute stage of epidural bleeding may be of clinical value. Due to the particular form of the time/pressure course, in epidural bleeding, this treatment may have considerable therapeutic value.
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TL;DR: In more than a thousand chronic obstructive lung disease patients, it was observed in six cases, that exercise-induced hypercapnia was accompanied by a concomitant improvement in arterial oxygen tension (PaO2) and a decrease in the alveolo-arterial O2.
Abstract: In more than a thousand chronic obstructive lung disease (COLD) patients we have observed in six cases, that exercise-induced hypercapnia was accompanied by a concomitant improvement in arterial oxygen tension (PaO2) and a decrease in the alveolo-arterial O2. This behaviour was not due to technical errors. We explained the increase in PaO2 during exercise by three nonmutually exclusive mechanisms: 1) an increase in the respiratory quotient; 2) the exercise induced increase in alveolar ventilation, although inadequate to match the increase in CO2 production, would be redistributed to previously poorly ventilated regions of the lung, these regions therefore receiving enough oxygen to arterialize the blood flowing through the alveolar capillaries; 3) alternatively, perfusion would be redistributed in a more efficient way during exercise, so that even in the presence of hypoventilation, oxygenation would be improved.