Showing papers on "Hypoventilation published in 1979"

Changes in Arterial Blood Gases during and after a Period of Oxygen Breathing in Patients with Chronic Hypercapnic Respiratory Failure and in Patients with Asthma

Abstract: Summary without an unacceptable rise in the arterial carbon 1. Ten patients with chronic hypercapnic respiratory failure (group 1) and eight patients with asthma (group 2) breathed pure 0, from an MC mask for 60 min. Blood gases were measured during this period and for the subsequent 45 min. 2. In nine of ten patients in group 1 and in all eight patients in group 2 arterial 0, tension (Pa,o,) fell to values lower than had been obtained before 0, was given. 3. These undershoots in P40, are unrelated to changing CO, stores or to hypoventilation, and are more likely due to persistence of altered ventilationperfusion ratios associated with 0, breathing. 4. Magnitude of the undershoots is usually small, and periods of less than 15 min off 0, are unlikely to be harmful.

Lung function in diaphragm pacing

Abstract: Electric stimulation of the diaphragm via the phrenic nerve to induce ventilation has recently been used for the long-term management of chronic ventilatory insufficiency. Since 1973 three patients with inadequate alveolar ventilation have been treated with diaphragm pacing at the Toronto Western Hospital. Two, who had quadriplegia due to lesions of the spinal cord in the upper cervical region and a severe restrictive ventilatory defect, were treated with continuous diaphragm pacing. The third patient required assisted nocturnal ventilation because of primary alveolar hypoventilation. All three patients tolerated the diaphragm pacing well, and pulmonary function tests showed satisfactory gas exchange with the patients breathing room air. This form of therapy seems to be a practical clinical method of managing chronic ventilatory failure in patients with lesions of the upper cervical cord or primary alveolar hypoventilation.

Mechanisms of hyperventilation in head injury: case report and review.

Abstract: We report the case of a head-injured patient with spontaneous hyperventilation who had recurrent episodes of relative hypoventilation associated with increases in intracranial pressure. Detailed ventilatory studies were performed during the 2nd week after injury. Our findings in this patient prompted us to review the possible mechanisms underlying the observed changes. We suggest that spontaneous hyperventilation in head injury is secondary to a decrease in cortical inhibitory influences on respiratory control mechanisms and that the transient episodes of relative hypoventilation observed in our patient may reflect modified ventilatory responses dependent on the altered state of consciousness. (Neurosurgery, 5: 701--707, 1979).

The role of intermittent positive pressure breathing in respiratory physiotherapy.

Abstract: This article reviews the value and limitations of I.P.P.B. as opposed to other treatment methods available to the respiratory physiotherapist. In the treatment of patients with airways obstruction I.P.P.B. is presented as having a limited role. Alternative measures such as the use of simple nebulisation, relaxation therapy and manual methods to remove secretions are described as being preferable to I.P.P.B. in most cases. I.P.P.B. has some value in the early post-operative care of some patients undergoing surgery which results in limitation to spontaneous deep breathing postoperatively. However other methods, notably incentive spirometry should also be considered for these patients. In the treatment and prevention of respiratory complications associated with neuromuscular and skeletal disorders I.P.P.B. can play a significant role in counteracting the possible effects of hypoventilation. I.P.P.B. should be considered as one method among many which is available to the physiotherapist to assist in the treatment of respiratory complications associated with medical and surgical conditions.

Respiratory insufficiency in surgery

Abstract: Acute respiratory insufficiency (ARI) (reduced PaO2 and/or increased PaCO2) in surgical patients is mostly caused by atelectasis or bronchopneumonia. These complications may develop if functional residual capacity (FRC) is reduced. Even in surgical patients with normal lungs the supine position, some pulmonary disorders after any general anaesthesia, pain, and atonic intestine cause reduced FRC in the postoperative phase. Successful prophylaxis is based on these mechanisms, which are described. The adult respiratory distress syndrome (ARDS, termed "shock lung" a few years ago) is the most dangerous pulmonary complication leading to ARI. The evaluation of clinical data sugggests that noxious factors only active for a short time (so called "triggers") may start the development of ARDS when some physiological conditions (so called "constellations"), such as low flow syndrome, reduced FRC and overhydration, pave the way for this. In the early state prognosis is good if the patient is ventilated (CPPV) and kept on the dry side, and if cardiac output is elevated compared to the normal value at rest. Once fully established, ARDS has such a poor prognosis that the need for earliest possible commencement of therapy must be stressed emphatically. The following values may be taken as clear and simple symptoms for early diagnosis: vital capacity below 15 ml/kg (reflects decreased FRC), PaO2 breathing spontaneously room air below 60 mm Hg or 8 kPa (reflects increased intrapulmonary right to left shunt or regional hypoventilation), and respiratory rate above 25/min (reflects loss of compliance).