Inspiratory pressure support reduces slowing of inspiratory muscle relaxation rate during exhaustive treadmill walking in severe COPD.

When patients with COPD walk to a state of intolerable dyspnea, there is excessive inspiratory muscle loading, as evidenced by slowing of the maximum relaxation rate of the inspiratory muscles, measured from esophageal pressure during a sniff (Sn Pes MRR). In this setting, inspiratory pressure support (IPS) delivered via an orofacial mask increases walking distance and reduces dyspnea, but the mechanism by which this benefit is achieved remains unclear. In this study we compared Sn Pes MRR after equidistant treadmill walking in six men with severe COPD (mean FEV1: 0.

Effect of L-arginine on renal blood flow in normal subjects and patients with hypoxic chronic obstructive pulmonary disease.

Background: L-arginine is the precursor of endothelium derived nitric oxide (NO) and increasing the available substrate may increase the production of NO. This has been shown by local infusion in peripheral vascular beds but there are few studies of the effects during systemic infusion. Renal vasoconstriction is known to be important in the pathogenesis of cor pulmonale in patients with hypoxic chronic obstructive pulmonary disease (COPD).

Exhaustive exercise slows inspiratory muscle relaxation rate in chronic obstructive pulmonary disease.

The excessive load placed on inspiratory muscles when patients with COPD exercise could lead to fatigue and contribute to exercise limitation. Slowing of maximal relaxation rate (MRR) of skeletal muscle is an early index of the fatiguing process. We investigated whether inspiratory muscle MRR slows when patients with COPD walk to exhaustion.

Exhaustive treadmill exercise does not reduce twitch transdiaphragmatic pressure in patients with COPD.

Reduced diaphragm contractility has been described in normal subjects after whole body endurance exercise, and it indicates low frequency fatigue (LFF); it is unknown whether LFF is of clinical importance. We therefore studied the effect of treadmill exercise to exhaustion on diaphragm contractility in six patients with severe chronic obstructive pulmonary disease (COPD) (mean FEV1, 0.71, 27% predicted).

Effect of inspiratory pressure support on exercise tolerance and breathlessness in patients with severe stable chronic obstructive pulmonary disease.

Background: In patients with chronic obstructive pulmonary disease exercise tolerance is commonly limited by breathlessness. These patients have an increased ventilatory load at rest which is exacerbated during exercise. The purpose of this study was to investigate the effect of supporting ventilation by non-invasive inspiratory pressure support (IPS) during submaximal treadmill exercise in such patients to see if they would experience less breathlessness and improve their exercise capacity.

Randomised controlled trial of nasal ventilation in acute ventilatory failure due to chronic obstructive airways disease.

Acute exacerbations of chronic obstructive airways disease (COAD) are a common cause of admission to hospital, and have a high mortality. Nasal intermittent positive pressure ventilation (NIPPV) has been used successfully in patients with respiratory failure due to neuromuscular and skeletal disorders, but the outcome of treatment in patients with COAD is less well known. We carried out a prospective randomised controlled trial of conventional treatment versus conventional treatment plus NIPPV, in 60 patients with acute ventilatory failure due to exacerbations of COAD.

Changes in oxygen saturation during inhalation induction of anaesthesia in children.

Changes in oxygen saturation (SaO2) were studied during induction of anaesthesia in 48 healthy children receiving halothane or isoflurane for outpatient dental extractions. Substantial reductions in SaO2 occurred in more than 50% of the children given isoflurane and were associated with the irritant effects of this agent on the airway. SaO2 was largely unaltered during the use of halothane.

Constitutive function of a positively regulated promoter reveals new sequences essential for activity.

A consensus "-10" recognition sequence for RNA polymerase was created at the positively regulated lambda Pre promoter by introducing three single base pair mutations. This altered promoter, Pre*, functions constitutively in vivo and in vitro at high efficiency despite very poor consensus "-35" region sequence homology. We examined the influence of the -35 region sequence information on promoter function by shifting the wild type -35 region +/- 2 base pairs relative to the -10 region consensus sequence and by completely replacing it with alternative DNA sequences.

Reye's syndrome: assessment of intracranial monitoring.

Direct measurements of arterial blood pressure and intracranial pressure were recorded in 39 patients aged 3.6 months to 5 years 11 months with Reye's syndrome judged to be stage 2 or beyond. Of 33 patients who survived, 27 made a full recovery and six were severely handicapped.

Reye's syndrome.

Reye's syndrome, an uncommon childhood encephalopathy of uncertain aetiology, is an important cause of mortality and permanent handicap. Since its recognition treatment has changed, current management focusing upon prevention or control of raised intracranial pressure. Prognosis is radically improved by early recognition and prompt transfer to a specialist centre.

Reversal of non-depolarising neuromuscular block in children: a comparison of atropine and glycopyrrolate in a mixture with neostigmine.

Atropine and glycopyrrolate were compared when given in a mixture with neostigmine for the reversal of non-depolarising neuromuscular block in children. Glycopyrrolate was an effective antimuscarinic agent and could be safely used as an alternative to atropine, although the advantages in this age group were not as marked as have been observed in adults.

Neonatal death in Northern Ireland.

A survey of neonatal deaths occurring over two years in Northern Ireland disclosed that many hospitals where babies could be born probably could not be staffed and equipped to deal effectively with major perinatal problems. The incidence of congenital malformations, especially neural tube defects, was high. A reduction in neonatal deaths from this cause might be expected if facilities for antenatal diagnosis and termination of pregnancy were made available, although this raises grave ethical problems.

Sensitivity to intravenous anaesthetics: a report of three cases.

Three patients with sensitivity to an intravenous anaesthetic-thiopentone, propanidid, and Althesin (alphadolone and alphaxalone)-are described. In the cases of thiopentone and Althesin the reaction was characterized by cardiovascular collapse, while bronchospasm also occurred with thiopentone. The reaction to propanidid was a direct skin sensitivity.