Endogenous angiotensin II in the regulation of hypoxic pulmonary vasoconstriction in anaesthetized dogs

INTRODUCTION: The role played by several vasoactive mediators that are synthesized and released by the pulmonary vascular endothelium in the regulation of hypoxic pulmonary vasoconstriction (HPV) remains unclear. As a potent vasoconstrictor, angiotensin II could be involved. We tested the hypothesis that angiotensin-converting enzyme inhibition by enalaprilat and type 1 angiotensin II receptor blockade by candesartan would inhibit HPV. METHODS: HPV was evaluated in anaesthetized dogs, with an intact pulmonary circulation, by examining the increase in the Ppa–Ppao gradient (mean pulmonary artery pressure minus occluded pulmonary artery pressure) that occurred in response to hypoxia (inspiratory oxygen fraction of 0.1) at constant pulmonary blood flow. Plasma renin activity and angiotensin II immunoreactivity were measured to determine whether activation or inhibition of the renin–angiotensin system was present. RESULTS: Administration of enalaprilat and candesartan did not affect the Ppa–Ppao gradient at baseline or during hypoxia. Plasma renin activity and angiotensin II immunoreactivity increased during hypoxia, and subsequent measurements were consistent with effective angiotensin-converting enzyme inhibition after administration of enalaprilat, and with angiotensin receptor blockade after administration of candesartan. CONCLUSION: These results suggest that, although the renin–angiotensin system was activated in hypoxia, angiotensin II is not normally involved in mediating acute HPV

Shoshin Beriberi and Severe Accidental Hypothermia as Causes of Heart Failure in a 6-Year-Old Child: A Case Report and Brief Review of Literature

Severe accidental hypothermia has been demonstrated to affect ventricular systolic and diastolic functions, and rewarming might be responsible of cardiovascular collapse. Until now, there have been only a few reports on severe accidental hypothermia, none of which involved children. Herein, we describe here a rare case of heart failure in a 6-year-old boy admitted to the emergency unit owing to severe hypothermia and malnutrition. After he was warmed up (core temperature of 27.2°C at admission), he developed cardiac arrest, requiring vasoactive amines administration, and veno-arterial extracorporeal membrane oxygenation. Malnutrition and refeeding syndrome might have caused the thiamine deficiency, commonly known as beriberi, which contributed to heart failure as well. He showed remarkable improvement in heart failure symptoms after thiamine supplementation. High-dose supplementation per os (500 mg/day) after reconstitution of an adequate electrolyte balance enabled the patient to recover completely within 2 weeks, even if a mild diastolic cardiac dysfunction persisted longer. In conclusion, we describe an original pediatric case of heart failure due to overlap of severe accidental hypothermia with rewarming, malnutrition, and refeeding syndrome with thiamine deficiency, which are rare independent causes of cardiac dysfunction. The possibility of beriberi as a cause of heart failure and adequate thiamine supplementation should be considered in all high-risk patients, especially those with malnutrition. Refeeding syndrome requires careful management, including gradual electrolyte imbalance correction and administration of a thiamine loading dose to prevent or correct refeeding-induced thiamine deficiency

Pediatric cardiac arrest registries and survival outcomes: A European study

Objective: The epidemiology of pediatric cardiac arrest in Europe is largely unknown. We aimed to characterize pediatric cardiac arrest registries and obtain the first survival outcome data on pediatric cardiac arrest in Europe. Design: This is a prospective multinational survey. Setting: We surveyed all 53 countries in Europe asking about: the existence registries for pediatric out-of-hospital cardiac arrest (pOHCA) and/or in-hospital cardiac arrest (pIHCA)), the data collected, and the structure of the registries. Subsequently, we investigated outcomes (number of pOHCA/pIHCA since start of the registry, return of spontaneous circulation (ROSC), survival to hospital discharge/30-day survival) from the countries with active registries. Patients and interventions: We obtained information from 33 countries including 25 of the 27 European Union states. Measurements and main results: Thirteen countries (39%) have an ongoing pediatric cardiac arrest registry (pOHCA: 11 countries, pIHCA: 8 countries). All use the Utstein template for data collection. Five countries (15%) collect data about CPR quality. Eleven countries (33%) expressed interest in European collaboration on registry data. Overall, 13 countries reported data on outcomes from a total of 17,708 pOHCAs and 2,743 pIHCAs. The ROSC rate after pOHCA ranges from 10% to 72% as compared to 60% to 72% after pIHCA. Survival to hospital discharge ranges from 16% to 39% after pOHCA as compared to 32% to 57% after pIHCA. Conclusions: Less than 40% of the European countries have a pOHCA and/or pIHCA registry, reporting a wide variety in survival rates, especially after pOHCA. More systematic data collection is needed to identify the real incidence and outcomes from pediatric cardiac arrest, ideally through a joint European registry

Paediatric out-of-hospital resuscitation in an area with scattered population (Galicia-Spain)

<p>Abstract</p> <p>Background</p> <p>Cardiorespiratory arrest (CRA) is a rare event in childhood. Our objective was to determine the characteristics of paediatric CRA and the immediate results of cardiopulmonary resuscitation (CPR) in Galicia, a community with a very scattered population.</p> <p>Methods</p> <p>All children (aged from newborn to 16 years old) who suffered an out-of-hospital CRA in Galicia and were assisted by the Public Foundation Medical Emergencies of Galicia-061 staff, from June 2002 to February 2005, were included in the study. Data were prospectively recorded following the Utstein's style guidelines.</p> <p>Results</p> <p>Thirty-one cases were analyzed (3.4 CRA annual cases per 100.000 paediatric population). The arrest was respiratory in 16.1% and cardiac in 83.9% of cases. CRA occurred at home in 58.1% of instances. Time CRA to initiation of CPR was shorter than 10 minutes in 32.2% and longer than 20 minutes in 29.0% of cases. 22.6% of children received bystander CPR. The first recorded rhythm was asystole in 67.7% of cases. Bag-mask ventilation was used in 67.7% and in 83.8% oro-tracheal intubation was done. A peripheral venous access was achieved in 67.7% and intraosseous access was used in 16.1% of patients. 93.5% of children were treated with adrenaline. After initial CPR, sustained restoration of spontaneous circulation was achieved in 38.7% of cases. Six children (19.4%) survived until hospital discharge. Four of 5 children with respiratory arrest survived, whereas only 2 of 26 children with cardiac arrest survived until hospital discharge.</p> <p>Conclusion</p> <p>Despite the handicap of a highly disseminated population, paediatric CRA characteristics and CPR results in Galicia are comparable to references from other communities. Programs to increase bystander CPR, equip laypeople with basic CPR skills and to update life support knowledge of health staff are needed to improve outcomes.</p

Clinical practice: Noninvasive respiratory support in newborns

The most important goal of introducing noninvasive ventilation (NIV) has been to decrease the need for intubation and, therefore, mechanical ventilation in newborns. As a result, this technique may reduce the incidence of bronchopulmonary dysplasia (BPD). In addition to nasal CPAP, improvements in sensors and flow delivery systems have resulted in the introduction of a variety of other types of NIV. For the optimal application of these novelties, a thorough physiological knowledge of mechanics of the respiratory system is necessary. In this overview, the modern insights of noninvasive respiratory therapy in newborns are discussed. These aspects include respiratory support in the delivery room; conventional and modern nCPAP; humidified, heated, and high-flow nasal cannula ventilation; and nasal intermittent positive pressure ventilation. Finally, an algorithm is presented describing common practice in taking care of respiratory distress in prematurely born infants