Pulse oximetry and oxygen services for the care of children with pneumonia attending frontline health facilities in Lagos, Nigeria (INSPIRING-Lagos): study protocol for a mixed-methods evaluation.

INTRODUCTION: The aim of this evaluation is to understand whether introducing stabilisation rooms equipped with pulse oximetry and oxygen systems to frontline health facilities in Ikorodu, Lagos State, alongside healthcare worker (HCW) training improves the quality of care for children with pneumonia aged 0-59 months. We will explore to what extent, how, for whom and in what contexts the intervention works. METHODS AND ANALYSIS: Quasi-experimental time-series impact evaluation with embedded mixed-methods process and economic evaluation. SETTING: seven government primary care facilities, seven private health facilities, two government secondary care facilities. TARGET POPULATION: children aged 0-59 months with clinically diagnosed pneumonia and/or suspected or confirmed COVID-19. INTERVENTION: 'stabilisation rooms' within participating primary care facilities in Ikorodu local government area, designed to allow for short-term oxygen delivery for children with hypoxaemia prior to transfer to hospital, alongside HCW training on integrated management of childhood illness, pulse oximetry and oxygen therapy, immunisation and nutrition. Secondary facilities will also receive training and equipment for oxygen and pulse oximetry to ensure minimum standard of care is available for referred children. PRIMARY OUTCOME: correct management of hypoxaemic pneumonia including administration of oxygen therapy, referral and presentation to hospital. SECONDARY OUTCOME: 14-day pneumonia case fatality rate. Evaluation period: August 2020 to September 2022. ETHICS AND DISSEMINATION: Ethical approval from University of Ibadan, Lagos State and University College London. Ongoing engagement with government and other key stakeholders during the project. Local dissemination events will be held with the State Ministry of Health at the end of the project (December 2022). We will publish the main impact results, process evaluation and economic evaluation results as open-access academic publications in international journals. TRIAL REGISTRATION NUMBER: ACTRN12621001071819; Registered on the Australian and New Zealand Clinical Trials Registry.

Cascos de ventilación no invasiva en pacientes con hipoxemia severa por COVID-19 / Non-invasive ventilation helmets in patients with severe hypoxemia due to COVID-19

CONTEXTO: Ante el avance de la pandemia COVID-19 muchas provincias argentinas se encuentran en el límite de saturación de su capacidad sanitaria, especialmente para los pacientes más críticos que requieren hospitalización, oxigenoterapia y asistencia respiratoria mecánica (ARM). Se han analizado distintas alternativas en los pacientes con hipoxemias moderadas a severas que no corrigen con máscara reservorio. METODOLOGÍA: Un equipo multidisciplinario e independiente de conflictos de interés con el proveedor de esta tecnología, y de tecnologías alternativas realizó una evaluación de tecnología sanitaria enfocada en responder las preguntas clínicas: 1. ¿Cuál es la eficacia de los cascos para ventilación no invasiva en los pacientes internados con COVID-19? 2. ¿Cuál es la seguridad de los cascos para ventilación no invasiva en los pacientes internados con COVID-19? 3. ¿Cuál es el costo y la factibilidad de incorporar cascos para ventilación no invasiva en los pacientes internados con COVID-19? 4. ¿Cuál es el potencial impacto en la red prestacional pública de los cascos para ventilación no invasiva en los pacientes internados con COVID-19? Se realizó una búsqueda bibliográfica en las principales bases de datos, en buscadores genéricos de internet, y financiadores de salud. Se dio prioridad a las Revisiones Sistemáticas (RS), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas (EE), guías de práctica clínica (GPC), políticas de cobertura (PC) de diferentes sistemas de salud, ensayos clínicos aleatorizados (ECA), y estudios observacionales, desde 2000 hasta agosto 2020 sin ninguna restricción de idioma. RESULTADOS: Descripción de la Tecnología: Este informe se centra en el casco marca ECLERIS, por tratarse de un dispositivo médico "de pared" que no requiere equipamiento mecánico complejo, por ser fabricado en Argentina, cuenta con autorización de la Administración Nacional de Medicamentos, Alimentos y Tecnología Médica (ANMAT), y su adquisición es más factible en el contexto de pandemia. Tecnologías Alternativas: En el presente informe la tecnología no se compara con equipos de ARM, sino con la mejor alternativa disponible cuando estos ya no se encuentran disponibles, qué es escenario asumido. Estas alternativas pueden ser aquellos dispositivos que ofrecen oxígeno suplementario a presión atmosférica (máscaras y máscaras reservorio). No se compara en este caso la VNI con el respirador, ya que en este escenario se asume agotada la capacidad de respiradores. Pese a lo cual se incluirán en las búsquedas y análisis de estudios o guías que analicen la comparación entre VNI y ARM para buscar información sobre seguridad. Acerca del contexto, se analiza su utilización en salas de internación, guardia de emergencias y derivaciones en ambulancia. CONCLUSIÓN: La mayoría de las autoridades sanitarias recomiendan, cuando está disponible, la intubación precoz y ARM en los pacientes con neumonía grave y SDRA por COVID. Al analizar la eficacia en los pocos estudios identificados (de baja calidad), estos preferencian la VNI en contraposición a la intubación temprana, basada en evidencia indirecta (proveniente de pacientes con SARS y MERS) y en un estudio descriptivo de SARS-Cov2. En esos contextos mostrarían disminución de la mortalidad, aunque es necesario realizar más estudios. En el presente informe los cascos de VNI tipo ECLERIS no se comparan con equipos de ARM, sino con la mejor alternativa cuando estos ya no se encuentran disponibles, que es el escenario asumido y esperado. Estas alternativas pueden ser aquellos dispositivos que ofrecen oxígeno suplementario a presión atmosférica (máscaras y máscaras reservorio). La capacidad de limitar el tratamiento a pacientes seleccionados puede amplificar los beneficios potenciales reduciendo la tasa de fracaso. Si la combinación de hCPAP y la posición prona redujera la tasa de intubación, el sistema de salud podría mejorar la asignación de camas de UCI, otorgando un mejor tratamiento a todos los pacientes que necesitan asistencia ventilatoria.

Case Report of an Autopsy of a Child Who Died in a Drum-Type Washing Machine Tub: Pathophysiology Resulting in Death and Assessment of Previous Literature.

The patient was a 5-year-old boy who was found in a state of cardiorespiratory arrest in the tub of a washing machine without water with the door closed. The autopsy findings included severe facial congestion and petechiae of the facial skin and palpebral conjunctiva. Several organs exhibited congestion. Hemorrhagic spots were seen on the serous membranes of various organs, with particularly marked hemorrhagic spots seen on the lungs. The heart contained fluid blood without soft clots. There were no findings indicative of marked trauma, intoxication, or hyperthermia. The examination results suggested that asphyxia had occurred in this case. However, there were no findings indicative of cervical compression, oronasal obstruction, or the presence of a foreign body in the respiratory tract. Image analysis showed the child could make postural changes inside the washing machine tub. Consequently, impaired thoracic movement and postural asphyxia were considered unlikely to have occurred. The results of blood gas analysis showed no evidence of marked hypercapnia. We, therefore, concluded that the cause of the child's death was asphyxia due to hypoxia caused by being in a closed space, that is, a washing machine tub.

IUGR decreases cardiomyocyte endowment and alters cardiac metabolism in a sex- and cause-of-IUGR-specific manner.

Intrauterine growth restriction (IUGR) increases the risk of ischemic heart disease in adulthood. Studies in rats suggest cardiac vulnerability is more pronounced in males and in offspring that were exposed to hypoxia in utero. Therefore, we aimed to test the hypotheses that 1) IUGR adolescent males, but not females, have fewer cardiomyocytes and altered expression of cardiometabolic genes compared with controls; and 2) IUGR due to hypoxia has a greater effect on these parameters compared with IUGR due to nutrient restriction. IUGR was induced in guinea pigs by maternal hypoxia (MH; 10% O2, n = 9) or maternal nutrient restriction (MNR; ~30% reduction in food intake, n = 9) in the second half of pregnancy and compared with control ( n = 11). At 120 days of age, postmortem was performed and the left ventricle perfusion fixed for stereological determination of cardiomyocyte number or snap frozen to determine the abundance of cardiometabolic genes and proteins by quantitative RT-PCR and Western blotting, respectively. MH reduced the number of cardiomyocytes in female ( P < 0.05), but not male or MNR, adolescent offspring. Furthermore, IUGR males had decreased expression of genes responsible for fatty acid activation in the sarcoplasm ( FACS) and transport into the mitochondria ( AMPK-a2 and ACC; P < 0.05) and females exposed to MH had increased activation/phosphorylation of AMP-activated protein kinase-α ( P < 0.05). We postulate that the changes in cardiomyocyte endowment and cardiac gene expression observed in the present study are a direct result of in utero programming, as offspring at this age did not suffer from obesity, hypertension, or left ventricular hypertrophy.

Nasal high flow therapy: a novel treatment rather than a more expensive oxygen device.

Nasal high flow is a promising novel oxygen delivery device, whose mechanisms of action offer some beneficial effects over conventional oxygen systems. The administration of a high flow of heated and humidified gas mixture promotes higher and more stable inspiratory oxygen fraction values, decreases anatomical dead space and generates a positive airway pressure that can reduce the work of breathing and enhance patient comfort and tolerance. Nasal high flow has been used as a prophylactic tool or as a treatment device mostly in patients with acute hypoxaemic respiratory failure, with the majority of studies showing positive results. Recently, its clinical indications have been expanded to post-extubated patients in intensive care or following surgery, for pre- and peri-oxygenation during intubation, during bronchoscopy, in immunocompromised patients and in patients with "do not intubate" status. In the present review, we differentiate studies that suggest an advantage (benefit) from other studies that do not suggest an advantage (no benefit) compared to conventional oxygen devices or noninvasive ventilation, and propose an algorithm in cases of nasal high flow application in patients with acute hypoxaemic respiratory failure of almost any cause.

Solar powered oxygen systems in remote health centers in Papua New Guinea: a large scale implementation effectiveness trial.

BACKGROUND: Pneumonia is the largest cause of child deaths in Papua New Guinea (PNG), and hypoxaemia is the major complication causing death in childhood pneumonia, and hypoxaemia is a major factor in deaths from many other common conditions, including bronchiolitis, asthma, sepsis, malaria, trauma, perinatal problems, and obstetric emergencies. A reliable source of oxygen therapy can reduce mortality from pneumonia by up to 35%. However, in low and middle income countries throughout the world, improved oxygen systems have not been implemented at large scale in remote, difficult to access health care settings, and oxygen is often unavailable at smaller rural hospitals or district health centers which serve as the first point of referral for childhood illnesses. These hospitals are hampered by lack of reliable power, staff training and other basic services. METHODS: We report the methodology of a large implementation effectiveness trial involving sustainable and renewable oxygen and power systems in 36 health facilities in remote rural areas of PNG. The methodology is a before-and after evaluation involving continuous quality improvement, and a health systems approach. We describe this model of implementation as the considerations and steps involved have wider implications in health systems in other countries. RESULTS: The implementation steps include: defining the criteria for where such an intervention is appropriate, assessment of power supplies and power requirements, the optimal design of a solar power system, specifications for oxygen concentrators and other oxygen equipment that will function in remote environments, installation logistics in remote settings, the role of oxygen analyzers in monitoring oxygen concentrator performance, the engineering capacity required to sustain a program at scale, clinical guidelines and training on oxygen equipment and the treatment of children with severe respiratory infection and other critical illnesses, program costs, and measurement of processes and outcomes to support continuous quality improvement. CONCLUSIONS: This study will evaluate the feasibility and sustainability issues in improving oxygen systems and providing reliable power on a large scale in remote rural settings in PNG, and the impact of this on child mortality from pneumonia over 3 years post-intervention. Taking a continuous quality improvement approach can be transformational for remote health services.

Cognitive Deterioration in Moderate and Severe Hypobaric Hypoxia Conditions.

BACKGROUND: Hypoxia continues to present risks in military aviation. Hypoxia symptoms include sensory and cognitive effects; of these, it is important to identify which components of operator performance are most vulnerable to hypoxia-induced decline in order to determine which sensory modality is most effective for alerting an impaired aviator of an imminent hypoxic episode. METHODS: A study was performed in a hypobaric chamber to characterize deterioration of cognitive performance under moderate (MH) and severe (SH) hypoxia conditions, culminating in subjects' inability to perform tasks. Subjects operated a synthetic workstation, performing multiple simultaneous tasks during hypobaric exposures equivalent to 5486 m (18,000 ft) MH and 7620 m (25,000 ft) SH ascents. Performance was compared across baseline, altitude exposure, and recovery periods within MH vs. SH altitude profiles. Ascents lasted until at least one of a list of termination criteria was met, at which point the chamber was returned to ground level pressure and the subject resumed workstation performance during recovery. RESULTS: SH conditions generated greater deficits than MH conditions, and these more severe effects hastened the termination of exposures (5 vs. 18 min mean duration, respectively). Workstation performance collapsed rapidly on SH exposure, with Mathematics and Auditory Monitoring tasks proving vulnerable to breakdown. In MH exposures, these tasks exhibited impaired accuracy (declining 11% and 9%, respectively) and speed, with declines in Auditory Monitoring lingering into recovery. DISCUSSION: The relative robustness of memory and visual monitoring vs. the vulnerability of mathematical and auditory processing suggest that care should be taken designing purely auditory cockpit hypoxia warning alerts.Beer JMA, Shender BS, Chauvin D, Dart TS, Fischer J. Cognitive deterioration in moderate and severe hypobaric hypoxia conditions. Aerosp Med Hum Perform. 2017; 88(7):617-626.

Early EEG for outcome prediction of postanoxic coma: prospective cohort study with cost-minimization analysis.

BACKGROUND: We recently showed that electroencephalography (EEG) patterns within the first 24 hours robustly contribute to multimodal prediction of poor or good neurological outcome of comatose patients after cardiac arrest. Here, we confirm these results and present a cost-minimization analysis. Early prognosis contributes to communication between doctors and family, and may prevent inappropriate treatment. METHODS: A prospective cohort study including 430 subsequent comatose patients after cardiac arrest was conducted at intensive care units of two teaching hospitals. Continuous EEG was started within 12 hours after cardiac arrest and continued up to 3 days. EEG patterns were visually classified as unfavorable (isoelectric, low-voltage, or burst suppression with identical bursts) or favorable (continuous patterns) at 12 and 24 hours after cardiac arrest. Outcome at 6 months was classified as good (cerebral performance category (CPC) 1 or 2) or poor (CPC 3, 4, or 5). Predictive values of EEG measures and cost-consequences from a hospital perspective were investigated, assuming EEG-based decision- making about withdrawal of life-sustaining treatment in the case of a poor predicted outcome. RESULTS: Poor outcome occurred in 197 patients (51% of those included in the analyses). Unfavorable EEG patterns at 24 hours predicted a poor outcome with specificity of 100% (95% CI 98-100%) and sensitivity of 29% (95% CI 22-36%). Favorable patterns at 12 hours predicted good outcome with specificity of 88% (95% CI 81-93%) and sensitivity of 51% (95% CI 42-60%). Treatment withdrawal based on an unfavorable EEG pattern at 24 hours resulted in a reduced mean ICU length of stay without increased mortality in the long term. This gave small cost reductions, depending on the timing of withdrawal. CONCLUSIONS: Early EEG contributes to reliable prediction of good or poor outcome of postanoxic coma and may lead to reduced length of ICU stay. In turn, this may bring small cost reductions.

Healthcare burden of pulmonary hypertension owing to lung disease and/or hypoxia.

BACKGROUND: Group 3 pulmonary hypertension (PH) encompasses PH owing to lung diseases and/or hypoxia. Treatment patterns, healthcare resource use, and economic burden to US payers of Group 3 PH patients were assessed. METHODS: This retrospective observational study extracted data from July 1, 2010 to June 30, 2013 from two Truven Health Analytics MarketScan databases. Adult Group 3 PH patients were identified based on claims for PH (ICD-9-CM 416.0/416.8), a related lung disease, and an echocardiogram or right heart catheterization (RHC). The index date was the date of the first PH claim; data were collected for 12 months pre- and post-index. A difference-in-difference approach using generalized estimating equations was done to account for baseline differences. RESULTS: Group 3 PH patients (n = 2,236) were matched 1:1 to controls on lung disease. PH patients had higher all-cause resource utilization and annual healthcare costs ($44,732 vs. $7,051) than controls. Costs were driven by inpatient admissions (35.4% of total costs), prescriptions (33.0%), and outpatient care (26.5%). Respiratory-related costs accounted for 11.4% of post-index annual costs for PH patients. PH diagnosis was not confirmed in the majority of PH patients (<7% RHC use) but nevertheless, 22% of PH patients post-index had claims for drugs approved for the treatment of pulmonary arterial hypertension (PAH). CONCLUSIONS: Group 3 PH poses a significant clinical and economic burden. Given the low use of RHC and the prevalence of PAH-indicated prescriptions that are not currently approved for Group 3 PH, this study suggests some Group 3 PH patients may not be receiving guideline-recommended treatment.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study.

BACKGROUND: The pneumococcal conjugate vaccine's (PCV) impact on childhood pneumonia during programmatic conditions in Africa is poorly understood. Following PCV13 introduction in Malawi in November 2011, we evaluated the case burden and rates of childhood pneumonia. METHODS AND FINDINGS: Between January 1, 2012-June 30, 2014 we conducted active pneumonia surveillance in children <5 years at seven hospitals, 18 health centres, and with 38 community health workers in two districts, central Malawi. Eligible children had clinical pneumonia per Malawi guidelines, defined as fast breathing only, chest indrawing +/- fast breathing, or, ≥1 clinical danger sign. Since pulse oximetry was not in the Malawi guidelines, oxygenation <90% defined hypoxemic pneumonia, a distinct category from clinical pneumonia. We quantified the pneumonia case burden and rates in two ways. We compared the period immediately following vaccine introduction (early) to the period with >75% three-dose PCV13 coverage (post). We also used multivariable time-series regression, adjusting for autocorrelation and exploring seasonal variation and alternative model specifications in sensitivity analyses. The early versus post analysis showed an increase in cases and rates of total, fast breathing, and indrawing pneumonia and a decrease in danger sign and hypoxemic pneumonia, and pneumonia mortality. At 76% three-dose PCV13 coverage, versus 0%, the time-series model showed a non-significant increase in total cases (+47%, 95% CI: -13%, +149%, p = 0.154); fast breathing cases increased 135% (+39%, +297%, p = 0.001), however, hypoxemia fell 47% (-5%, -70%, p = 0.031) and hospital deaths decreased 36% (-1%, -58%, p = 0.047) in children <5 years. We observed a shift towards disease without danger signs, as the proportion of cases with danger signs decreased by 65% (-46%, -77%, p<0.0001). These results were generally robust to plausible alternative model specifications. CONCLUSIONS: Thirty months after PCV13 introduction in Malawi, the health system burden and rates of the severest forms of childhood pneumonia, including hypoxemia and death, have markedly decreased.

Assessment of tumor oxygenation and its impact on treatment response in bevacizumab-treated recurrent glioblastoma.

Antiantiogenic therapy with bevacizumab in recurrent glioblastoma is currently understood to both reduce microvascular density and to prune abnormal tumor microvessels. Microvascular pruning and the resulting vascular normalization are hypothesized to reduce tumor hypoxia and increase supply of systemic therapy to the tumor; however, the underlying pathophysiological changes and their timing after treatment initiation remain controversial. Here, we use a novel dynamic susceptibility contrast MRI-based method, which allows simultaneous assessment of tumor net oxygenation changes reflected by the tumor metabolic rate of oxygen and vascular normalization represented by the capillary transit time heterogeneity. We find that capillary transit time heterogeneity, and hence the oxygen extraction fraction combine with the tumoral blood flow (cerebral blood flow) in such a way that the overall tumor oxygenation appears to be worsened despite vascular normalization. Accordingly, hazards for both progression and death are found elevated in patients with a greater reduction of tumor metabolic rate of oxygen in response to bevacizumab and patients with higher intratumoral tumor metabolic rate of oxygen at baseline. This implies that tumors with a higher degree of angiogenesis prior to bevacizumab-treatment retain a higher level of angiogenesis during therapy despite a greater antiangiogenic effect of bevacizumab, hinting at evasive mechanisms limiting bevacizumab efficacy in that a reversal of their biological behavior and relative prognosis does not occur.

In silico study of the impact of cancer stem cell dynamics and radiobiological hypoxia on tumour response to hyperfractionated radiotherapy.

OBJECTIVES: Advanced head and neck carcinomas (HNCs) are aggressive tumours, mainly due to hypoxia and a cancer stem cell (CSC) subpopulation. The aim of this study was to simulate tumour growth and behaviour during radiotherapy of three HNC groups (governed by different growth kinetics, hypoxia levels and CSC division pattern) to determine correlation between resistance factors and responses to hyperfractionated radiotherapy. METHODS: An in silico HNC model was developed based on biologically realistic input parameters. During radiotherapy simulation, three parameters were studied: growth kinetics, hypoxia and probability of CSC symmetrical division. Both independent and combined effects on tumour response to hyperfractionated radiotherapy were assessed. RESULTS: Oxic and very mildly hypoxic HNCs were revealed to be controlled by hyperfractionated radiotherapy, irrespective of growth kinetics and CSC division pattern. Moderately hypoxic tumours had different responses to radiotherapy: while slowly proliferating HNCs were still controllable, tumours with higher cell turnover were more resistant. In rapidly proliferating tumours, the number of fractions needed for tumour control increased exponentially with the probability of CSC symmetrical division, whereas in moderately growing HNC, this behaviour was linear. Severely hypoxic tumours could not be controlled by radiotherapy alone. Tumours with CSCs in a severely hypoxic niche required adjuvant therapies to be eradicated. CONCLUSIONS: Growth kinetics strongly influence tumour responses to treatment. Slowly growing tumours showed linear dependence between dose and hypoxia/CSC, whereas rapidly growing tumours followed exponential behaviour.

Evaluating the impact of pulse oximetry on childhood pneumonia mortality in resource-poor settings.

It is estimated that pneumonia is responsible for 15% of childhood deaths worldwide. Recent research has shown that hypoxia and malnutrition are strong predictors of mortality in children hospitalized for pneumonia. It is estimated that 15% of children under 5 who are hospitalized for pneumonia have hypoxaemia and that around 1.5 million children with severe pneumonia require oxygen treatment each year. We developed a deterministic compartmental model that links the care pathway to disease progression to assess the impact of introducing pulse oximetry as a prognostic tool to distinguish severe from non-severe pneumonia in under-5 year olds across 15 countries with the highest burden worldwide. We estimate that, assuming access to supplemental oxygen, pulse oximetry has the potential to avert up to 148,000 deaths if implemented across the 15 countries. By contrast, integrated management of childhood illness alone has a relatively small impact on mortality owing to its low sensitivity. Pulse oximetry can significantly increase the incidence of correctly treated severe cases as well as reduce the incidence of incorrect treatment with antibiotics. We also found that the combination of pulse oximetry with integrated management of childhood illness is highly cost-effective, with median estimates ranging from US$2.97 to $52.92 per disability-adjusted life year averted in the 15 countries analysed. This combination of substantial burden reduction and favourable cost-effectiveness makes pulse oximetry a promising candidate for improving the prognosis for children with pneumonia in resource-poor settings.

[Controversy in the treatment of a critically ill neonate in a rural health service]. / Controversias sobre el tratamiento de un neonato críticamente enfermo en un servicio de salud rural.

Cardiopulmonary resuscitation of newborns with perinatal hypoxia faces serious ethical, moral, medical and legal problems, particularly in rural areas. Ethical and moral issues have to do with the medical-parents relationship; with values, preferences and priorities of each of these groups; and with the scarce resources situation. Medical-technical problems are related to asphyxia complications, and their prognostic and therapeutic implications. Legal considerations arising from the fact of killing or letting die. In this article is analyzed the real case of a neonate with severe perinatal hypoxia in order to enhance the understanding of the incorporation of ethics in everyday clinical practice.

La reanimación cardiopulmonar de recién nacidos con hipoxia perinatal grave enfrenta problemas éticos, morales, médicos y legales, particularmente en áreas rurales. Los problemas éticos y morales tienen que ver con la relación médico-padres; con los valores, preferencias y prioridades de cada uno de estos grupos, y con la situación de la escasez de recursos. Los problemas técnico-médicos están relacionados con las complicaciones relacionadas a la asfixia, así como con sus implicaciones pronósticas y terapéuticas. Mientras que las consideraciones legales derivan del hecho de matar o dejar morir. En este artículo se discute el caso real de un neonato con asfixia perinatal grave con el propósito de fortalecer el entendimiento de la incorporación de la ética de la práctica clínica cotidiana.

A pilot assessment of alpha-stat vs pH-stat arterial blood gas analysis after cardiac arrest.

PURPOSE: Resuscitated cardiac arrest (CA) patients typically receive therapeutic hypothermia, but arterial blood gases (ABGs) are often assessed after adjustment to 37°C (alpha-stat) instead of actual body temperature (pH-stat). We sought to compare alpha-stat and pH-stat assessment of PaO2 and PaCO2 in such patients. MATERIALS AND METHODS: Using ABG data obtained during the first 24 hours of intensive care unit admission, we determined the impact of measured alpha vs calculated pH-stat on PaO2 and PaCO2 on patient classification and outcomes for CA patients. RESULTS: We assessed 1013 ABGs from 120 CA patients with a median age of patients 66 years (interquartile range, 50-76). Median alpha-stat PaO2 changed from 122 (95-156) to 107 (82-143) mm Hg with pH-stat and median PaCO2 from 39 (34-46) to 35 (30-41) mm Hg (both P < .001). Using the categories of hyperoxemia, normoxemia, and hypoxemia, pH-stat estimation of PaO2 reclassified approximately 20% of patients. Using the categories of hypercapnia, normocapnia, and hypocapnia, pH stat estimation of PaCO2 reclassified approximately 40% of patients. The mortality of patients in different PaO2 and PaCO2 categories was similar for pH-stat and alpha-stat. CONCLUSIONS: Using the pH-stat method, fewer resuscitated CA patients admitted to intensive care unit were classified as hyperoxemic or hypercapnic compared with alpha-stat. These findings suggest an impact of ABG assessment methodology on PaO2, PaCO2 , and patient classification but not on associated outcomes.

[Recommendations for pediatric oxygen therapy in acute and chronic settings: Needs assessment, implementation criteria, prescription practices and follow-up]. / Recommandations pour l'oxygénothérapie chez l'enfant en situations aiguës et chroniques : évaluation du besoin, critères de mise en route, modalités de prescriptions et de surveillance.

Recommendations for acute and long-term oxygen therapy (needs assessment, implementation criteria, prescription practices, and follow-up) in children were produced by the Groupe de Recherche sur les Avancées en Pneumo-Pédiatrie (GRAPP) under the auspices of the French Paediatric Pulmonology and Allergology Society (SP2A). The Haute Autorité de Santé (HAS) methodology, based on the Formalized Consensus, was used. A first panel of experts analyzed the English and French literature to provide a second panel of experts with recommendations to validate. Only the recommendations are presented here, but the full text (arguments+recommendations) is available at the website of the French Paediatric Society: www.sfpediatrie.com.

Red cell volume expansion at altitude: a meta-analysis and Monte Carlo simulation.

INTRODUCTION: Altitude acclimatization is associated with a rapid increase in hematocrit. The time course and the contribution of the red cell volume expansion are not clear. The purpose of the present meta-analysis was to explore how much altitude exposure is required to induce polycythemia in healthy lowlanders. METHODS: A systematic review was performed of 66 published articles (including 447 volunteers) identified through literature search. We performed a mixed-model random-effects meta-analysis and a Monte Carlo simulation on the extracted data. RESULTS: The following results were obtained in this study: 1) the red cell volume expansion for a given duration of exposure is dependent on altitude (P < 0.0001), that is, that the increase in red cell volume was accelerated at higher altitudes; and 2) the extent of the erythropoietic response depends on the initial red cell volume (P < 0.0001). It seems that exposure time must exceed 2 wk at an altitude of more than 4000 m to exert a statistically significant effect. At lower altitudes, longer exposure times are needed with altitudes lower than 3000 m not yielding an increase within 4 wk. CONCLUSIONS: Red cell volume response to hypoxia is generally slow, although it accelerates with increasing altitude. This, in combination with a dependency on initial red cell volume, suggests that, for example, athletes may need to spend more time at altitude to see an effect on red cell volume than commonly recommended.

The assessment of time-dependent myocardial changes in infants with perinatal hypoxia.

OBJECTIVE: The aim of the study was to assess myocardial damage in infants due to perinatal hypoxia. METHODS: The findings of 29 infants with perinatal hypoxia and 20 healthy infants were compared. Blood gas analysis, serum lactate, cardiac troponin I (cTnI), troponin T (cTnT), creatine kinase-MB (CK-MB) and B-type natriuretic peptide (BNP) were evaluated. Echocardiography together with tissue Doppler imaging was performed. RESULTS: cTnT, CK-MB and BNP were higher in patients at the first day. There were positive correlations between the left ventricular (LV) myocardial performance index (MPI) and cTnT at first day and also at first month. LV ejection fraction and fractional shortening were lower at first day and at first month in patients. Myocardial systolic (Sm) and diastolic (Em and Am) velocities at all segments were lower at first day, and interventricular septum Sm, LV Sm, LV Em, right ventricular Em and LV Am were still lower at first month in patients. Isovolumic relaxation time at all segments together with LV MPI was higher at first day, ejection time values were lower and MPI values were higher at all segments at first month in patients. CONCLUSIONS: These findings demonstrated that the signs of myocardial damage due to perinatal hypoxia still present at first month.

Doppler echocardiographic assessment of left ventricular diastolic function in chronic hypoxic rats.

Little information is available on the mechanism of diastolic left ventricular (LV) dysfunction in patients with chronic respiratory disease complicated by hypoxia. The purpose of this study was to investigate how chronic hypoxia impairs LV diastolic function in an hypoxic animal model. Thirty-six male Wistar rats 8 weeks old were assigned to normoxia (N), chronic hypoxia (CH), and re-normoxia (RN) groups, 12 rats per group. The N group rats were kept in ambient air for 8 weeks, while the CH group was kept hypoxic for 8 weeks. After 8 weeks of hypoxia the RN group rats were kept for a further 8 weeks in ambient air. LV systolic and diastolic functions, as well as right ventricular (RV) function, were analyzed using Doppler echocardiography;we also measured the hematocrit, and weighed the LV and RV. Hematocrit, RV weight/body weight, and RV weight/LV weight were higher in the CH group than in the other 2 groups. However, most of these parameters returned to normoxia levels after re-normoxia. In the CH group, LV dimension and area were smaller than in the other 2 groups. LV systolic function was preserved in all groups;however, in the CH group, mitral flow showed a restrictive pattern, while pulmonary flow demonstrated a pulmonary hypertensive pattern with prolonged RV ejection time. In conclusion, chronic hypoxia induced pulmonary hypertension and RV hypertrophy. Although LV systolic function was preserved, diastolic function was impaired in hypoxia. Ventricular interaction may impair LV diastolic function.

Recovering at the cost of amnesia?

Despite the great progress of psychiatry, many of its fundamental problems remain unresolved. Obviously, new ideas that expand the present understanding of such problems are useful. In this paper, the following hypothesis is proposed: mental disorders are caused by hypoxic phenomena, stimulating hypertrophied growth of a neural network; treatment should be directed towards the damaging of abnormal elements of this network; successful treatment is inevitably accompanied by moderate retrograde amnesia. Based on this hypothesis, the connection between etiology, pathogenesis, and therapy of mental disorders is described, the role of retrograde amnesia is shown, and potential new methods of treatment (shaking, vibration, and ultrasound) are predicted. To test the hypothesis, some means are discussed. The first means is based on the analysis of the reasons of unsuccessful clinical trials of the method of mental disorders treatment by acute hypoxic hypoxia (USA, 1938-1940). Such a method, according to the hypothesis, should damage the abnormal elements of a neural network as a result of acute hypoxia. Analysis of the equipment and procedure shows that the trials were unsuccessful as a result of insufficiently powerful hypoxic influence. Improvements to this method are proposed. When using this method, it is advisable to measure the cerebral blood oxygenation index and reduce it by regulating the oxygen concentration in the hypoxic gas mixture given to the patient. This reduction should continue until the patient reaches a state of moderate retrograde amnesia. It is also advisable to note the blood oxygenation index value at the moment when the patient lapses into unconsciousness, and then, on the basis of this value, estimate a necessary power (i.e., acuteness and duration) of hypoxic hypoxia. Other means for testing the hypothesis are also discussed: retrospective analysis of the results of electroconvulsive therapy, and testing the predicted methods of treatment.