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Background: Vasopressin is an alternative drug to adrenaline in intractable ventricular fibrillation. However, vasopressin can cause significant bradycardia, resulting in reduced cardiac output. We investigated whether pre-treatment with atropine abrogates vasopressin-induced bradycardia in a beating-heart canine model., Material/methods: Five adult mongrel dogs received endotracheal vasopressin (1.0 U/kg) with or without endotracheal atropine (0.02 mg/kg) or a placebo (10 ml saline) after being anesthetized and ventilated. Hemodynamic variables and arterial blood gases were determined. Each dog (studied 3 times, one week apart) served as its own control., Results: Endotracheal vasopressin produced early and significant (p<0.05) bradycardia (from 55+/-7 mmHg to 35+/-5 beats/min) compared with controls, starting one minute post-injection and lasting one hour. In contrast, in atropine-pretreated animals the heart rate increased significantly (p<0.05) for as long as one hour post-atropine and vasopressin administration. In addition, animals treated with vasopressin with or without atropine exhibited a significant rise in diastolic blood pressure (from 83+/-5 to 160+/-15 and from 83+/-3 to 108+/-10 mmHg, respectively). Systolic and mean blood pressures also increased significantly compared with controls. Blood gases remained unchanged in all groups., Conclusions: Endotracheal administration of vasopressin can cause protracted bradycardia. Pretreatment with atropine can abrogate this effect. We suggest that atropine administration be considered when vasopressin is administered during cardio-pulmonary resuscitation. Further studies are warranted to evaluate the effect of vasopressin and atropine in a closed-chest model of cardio-pulmonary resuscitation.

Background: Pulmonary disease is the most frequent cause of morbidity and mortality in cystc fibrosis patients. New techniques such as non-invasive positive pressure ventilation have resulted in prolongation of life expectancy in CF patients with end-stage lung disease., Objectives: To determine the role of NIPPV in CF patients awaiting lung transplantation., Methods: Between 1996 and 2001 nine CF patients (5 females) with end-stage lung disease were treated with bi-level positive airway pressure ventilation in the "spontaneous" mode., Results: The patients' mean age at initiation of BiPAP was 15 years (range 13-40 years) and the mean duration of BiPAP usage was 8 months (range 3-16 months). Four patients underwent successful lung transplantation, three patients died while awaiting transplantation, and the remaining two are still on NIPPV while waiting for transplantation. Patients' body mass index increased significantly (P < 0.05) during BiPAP therapy (from 16.1 to 17.2 kg/m2). Blood pH, PaCO2, and bicarbonate improved significantly (from 7.31 to 7.38, 90.8 to 67.2 mmHg, and 48.9 to 40.3 mEq/L, respectively). Pulmonary function tests were not affected by BiPAP usage. The patients experienced a significant alleviation in morning headaches and improvement in quality of sleep (P < 0.003). There were no major complications during BiPAP usage., Conclusions: We demonstrated that long-term NIPPV can stabilize and improve physiologic parameters such as ventilation, arterial blood gases and body mass index, as well as subjective symptoms such as sleep pattern, daily activity level, and morning headaches in CF patients with end-stage lung disease. Further prospectively controlled studies are needed to evaluate the potential of BiPAP therapy and its influence on morbidity and mortality in the post-lung transplantation period.