48 research outputs found
Obstructive sleep apnea and pulmonary hypertension
No full textObstructive sleep apnea (OSA) is associated with repetitive nocturnal arterial oxygen desaturation and hypercapnia, large intrathoracic negative pressure swings, and acute increases in pulmonary artery pressure. Rodents when exposed to brief, intermittent hypoxia for several hours per day to mimic OSA developed pulmonary vascular remodeling and sustained pulmonary hypertension and right ventricular hypertrophy within a few weeks. Until recently, however, it was unclear whether episodic nocturnal hypoxemia associated with OSA was sufficient to cause similar changes in humans. This controversy appears to have been resolved by several recent studies that have shown (a) pulmonary hypertension in 20% to 40% of patients with OSA in the absence of other known cardiopulmonary disorders and (b) reductions in pulmonary artery pressure in patients with OSA after nocturnal continuous positive airway pressure (CPAP) treatment. The pulmonary hypertension associated with OSA appears to be mild and may be due to a combination of precapillary and postcapillary factors including pulmonary arteriolar remodeling and hyperreactivity to hypoxia and left ventricular diastolic dysfunction and left atrial enlargement. Although measurable changes in the structure and function of the right ventricle have been reported in association with OSA, the clinical significance of these changes is uncertain. Right ventricular failure in OSA appears to be uncommon and is more likely if there is coexisting left-sided heart disease or chronic hypoxic respiratory disease.Dimitar Sajkov and R. Doug McEvo
Comparison of effects of sustained isocapnic hypoxia on ventilation in men and women
No full text Sajkov, Dimitar, Alister Neill, Nicholas A. Saunders, and R. Douglas McEvoy. Comparison of the effects of sustained isocapnic hypoxia on ventilation in men and women. J. Appl. Physiol. 83(2): 599–607, 1997.—Sleep-related respiratory disturbances are more common in men than in premenopausal women. This might, in part, be due to different susceptibilities to the respiratory depressant effects of hypoxia. Therefore, we compared ventilation during 10 min of baseline room-air breathing and 20-min sustained isocapnic hypoxia (fractional inspired O2 = 11%, arterial saturation of O2 ≈ 80%) followed by 10 min of breathing 100% O2 in 10 normal men and in 10 women in the follicular phase of the menstrual cycle. Control measurements were made during two transitions from room air (10 min) to 100% O2 (10 min) and averaged. Inspired minute ventilation (V˙i) after 2 min of hypoxia was the same in men and women [131 ± 6.1% baseline for men, 136 ± 7.7% baseline for women; not significant (NS)] and declined to the same level after 20 min (115 ± 5.0% baseline for men, 116 ± 6.6% baseline for women; NS) associated with a similar decline in inspiratory time and tidal volume. Breathing frequency did not change.V˙i decreased transiently during subsequent 100% O2 breathing in both men and women, associated with reduced frequency and duty cycle and increased expiratory time. The fall inV˙i was significantly greater than that observed during control hyperoxia experiments in men but not in women. We conclude that ventilatory responses to sustained isocapnic hypoxia do not differ between awake healthy men and women in the follicular phase of their menstrual cycle. However, after termination of isocapnic hypoxia, men appear to depress their ventilation to a greater degree than women. </jats:p
Accidental Rivaroxaban Overdose in a Patient with Pulmonary Embolism: Some Lessons for Managing New Oral Anticoagulants
No full textRivaroxaban is an orally active direct factor Xa inhibitor used to treat venous thromboembolism with approved starting dose of 15 mg twice-daily. We present a case of an accidental overdose in a patient with pulmonary thromboembolism, when the patient received two 150 mg doses of rivaroxaban, instead of 15 mg as prescribed, given 12 hours apart. This error was recognised ten minutes after the second dose, when 50 gm oral activated charcoal was given. Rivaroxaban was stopped and rivaroxaban concentrations, INR, and APTT were monitored. The overdose was uncomplicated and 15 mg twice-daily rivaroxaban was restarted on day two. Apparently unlikely and potentially hazardous dispensing errors do happen. Each oral anticoagulant has a different dosing schedule. In our patient, the prescription for 15 mg twice-daily rivaroxaban was misread as 150 mg twice-daily (a correct dose for dabigatran in atrial fibrillation). Such errors are preventable. Prompt administration of activated charcoal under monitoring of a specific rivaroxaban assay can greatly help management of unusual situations like this one
Sleep apnoea related hypoxia is associated with cognitive disturbances in patients with tetraplegia
No full textSleep disordered breathing is common in patients with tetraplegia. Nocturnal arterial hypoxemia and sleep fragmentation due to sleep apnoea may be associated with cognitive dysfunction. We therefore studied the influence of sleep disordered breathing on neuropsychological function in 37 representative tetraplegic patients (mean age 34±9.7 years). Thirty percent (11 of 37 patients) had clinically significant sleep disordered breathing, defined as apnoea plus hypopnoea index (AHI) greater than 15 per hour of sleep. Most apnoeas were obstructive in type. Seven patients (19%) desaturated to <80% during the night. Neuropsychological variables were significantly correlated with measures of sleep hypoxia, but not with the AHI and the frequency of sleep arousals. The neuropsychological functions most affected by nocturnal desaturation were: verbal attention and concentration, immediate and short-term memory, cognitive flexibility, internal scanning and working memory. There appeared to be a weak association between the presence of severe sleep hypoxia and visual perception, attention and concentration but no association was found between sleep variables and depression scores. We concluded that sleep disordered breathing is common in patients with tetraplegia and may be accompanied with significant oxygen desaturation. The latter impairs daytime cognitive function in these patients, particularly attention, concentration, memory and learning skills. Cognitive disturbances resulting from sleep apnoea might adversely affect rehabilitation in patients with tetraplegia.Dimitar Sajkov, Ruth Marshall, Pieter Walker, Ivanka Mykytyn, R Douglas McEvoy, Jo Wale, Howard Flavel, Andrew T Thornton and Ral Anti
New cost-effective pleural procedure training: Manikin-based model to increase the confidence and competency in trainee medical officers
No full textPurpose of the study: Pleural diseases are common in clinical practice. Doctors in training often encounter these patients and are expected to perform diagnostic and therapeutic pleural procedures with confidence and safely. However, pleural procedures can be associated with significant complications, especially when performed by less experienced. Structured training such as use of training manikin and procedural skills workshop may help trainee doctors to achieve competence. However, high costs involved in acquiring simulation technology or attending a workshop may be a hurdle. We hereby describe a training model using a simple manikin developed in our institution and provide an effective way to document skill acquisition and assessment among trainee medical officers. Study design: This was a prospective observational study. The need for training, competence and confidence of trainees in performing pleural procedures was assessed through an online survey. Trainees underwent structured simulation training through a simple manikin developed at our institute. Follow-up survey after the training was then performed to access confidence and competence in performing pleural procedures. Results: Forty-seven trainees responded to an online survey and 91% of those expressed that they would like further training in pleural procedure skills. 81% and 85% of responders, respectively, indicated preferred method of training is either practising on manikin or performing the procedure under supervision. Follow-up survey showed improvement in the confidence and competence. Conclusion: Our pleural procedure training manikin model is a reliable, novel and cost-effective method for acquiring competences in pleural procedures.</p
Pulmonary Hypertension
No full textThis volume presents overviews as well as in depth reviews of many aspects of the clinical presentation, pathophysiology, and treatment of Pulmonary Hypertension (PH) especially PH related to thromboembolic disease. Saleem Sharieff presents a comprehensive synopsis of the epidemiologic, clinical, histopathologic, and therapy of PAH. Next, Dimitar Sajkov, Bliegh Mupunga, Jeffrey J. Bowden, and Nikolai Petrovsky comprehensively review World Health Organization group III PH. The cellular and biochemical pathophysiology of PH are summarized by Rajamma Mathew. Specific mechanisms implicated in the pathogenesis of PH are presented by Junko Maruyama, Ayumu Yokochi, Erquan Zhang, Hirohumi Sawada, Kazuo Maruyama; and Aureliano Hernandez and Rafael A. Areiza. Jean Elwing and Ralph Panos discuss PH associated with acute thromboembolism. Mehdi Badidi and M Barek Naz discuss PH caused by chronic thromboembolic disease. Juan C. Grignola, Maria J. Ruiz-Cano, Juan P. Salisbury, Gabriela Pascal, Pablo Curbelo, and Pilar Escribano present the physiologic assessment of patients with chronic thromboembolic disease prior to surgical pulmonary endarterectomy and, finally, Henry Liu, Philip L. Kalarickal, Yiru Tong, Daisuke Inui, Michael J Yarborough, Kavitha A. Mathew, Amanda Gelineau, and Charles Fox comprehensively review the clinical perioperative evaluation and management of patients with PH due to chronic thromboembolic disease
