We report 4.5 µm luminosities for 27 nearby (D 5 Mpc) dwarf irregular galaxies measured with the Spitzer Infrared Array Camera. We have constructed the 4.5 µm luminosity-metallicity (L-Z) relation for 25 dwarf galaxies with secure distance and interstellar medium oxygen abundance measurements. The 4.5 µm L-Z relation is 12+log(O/H) = (5.78 ± 0.21) + (−0.122 ± 0.012) M [4.5] , where M [4.5] is the absolute magnitude at 4.5 µm. The dispersion in the near-infrared L-Z relation is smaller than the corresponding dispersion in the optical L-Z relation. The subsequently derived stellar mass-metallicity (M * -Z) relation is 12+log(O/H) = (5.65 ± 0.23) + (0.298 ± 0.030) log M * , and extends the SDSS M * -Z relation to lower mass by about 2.5 dex. We find that the dispersion in the M * -Z relation is similar over five orders of magnitude in stellar mass, and that the relationship between stellar mass and interstellar medium metallicity is similarly tight from high-mass to low-mass systems. We find a larger scatter at low mass in the relation between effective yield and total baryonic mass. In fact, there are a few dwarf galaxies with large yields, which is difficult to explain if galactic winds are ubiquitous in dwarf galaxies. The low scatter in the L-Z and M * -Z relationships are difficult to understand if galactic superwinds or blowout are responsible for the low metallicities at low mass or luminosity. Naively, one would expect an ever increasing scatter at lower masses, which is not observed.

June 23/30, 2020 e933 Existing American Heart Association cardiopulmonary resuscitation (CPR) guidelines do not address the challenges of providing resuscitation in the setting of the coronavirus disease 2019 (COVID-19) global pandemic, wherein rescuers must continuously balance the immediate needs of the patients with their own safety. To address this gap, the American Heart Association, in collaboration with the American Academy of Pediatrics, American Association for Respiratory Care, American College of Emergency Physicians, The Society of Critical Care Anesthesiologists, and American Society of Anesthesiologists, and with the support of the American Association of Critical Care Nurses and National Association of EMS Physicians, has compiled interim guidance to help rescuers treat individuals with cardiac arrest with suspected or confirmed COVID-19.Over the past 2 decades, there has been a steady improvement in survival after cardiac arrest occurring both inside and outside the hospital. 1 That success has relied on initiating proven resuscitation interventions such as high-quality chest compressions and defibrillation within seconds to minutes. The evolving and expanding outbreak of severe acute respiratory syndrome coronavirus 2 infections has created important challenges to such resuscitation efforts and requires potential modifications of established processes and practices. The challenge is to ensure that patients with or without COVID-19 who experience cardiac arrest get the best possible chance of survival without compromising the safety of rescuers, who will be needed to care for future patients. Complicating the emergency response to both out-of-hospital and in-hospital cardiac arrest is that COVID-19 is highly transmissible, particularly during resuscitation, and carries a high morbidity and mortality.Approximately 12% to 19% of COVID-positive patients require hospital admission, and 3% to 6% become critically ill. [2][3][4] Hypoxemic respiratory failure secondary to acute respiratory distress syndrome, myocardial injury, ventricular arrhythmias, and shock are common among critically ill patients and predispose them to cardiac arrest, [5][6][7][8] as do some of the proposed treatments such as hydroxychloroquine and azithromycin, which can prolong the QT. 9 With infections currently growing exponentially in the United States and internationally, the percentage of patients with cardiac arrests and COVID-19 is likely to increase.Healthcare workers are already the highest-risk profession for contracting the disease. 10 This risk is compounded by worldwide shortages of personal protective equipment (PPE). Resuscitations carry added risk to healthcare workers for many reasons. First, the administration of CPR involves performing numerous aerosol-generating procedures, including chest compressions, positive-pressure ventilation, and establishment of an advanced airway. During those procedures, viral particles can remain suspended in the air with a half-life of ≈1 hour and

No abstract

The transition from intrauterine to extrauterine life that occurs at the time of birth requires timely anatomic and physiologic adjustments to achieve the conversion from placental gas exchange to pulmonary respiration. This transition is brought about by initiation of air breathing and cessation of the placental circulation. Air breathing initiates marked relaxation of pulmonary vascular resistance, with considerable increase in pulmonary blood flow and increased return of now-welloxygenated blood to the left atrium and left ventricle, as well as increased left ventricular output. Removal of the lowresistance placental circuit will increase systemic vascular resistance and blood pressure and reduce right-to-left shunting across the ductus arteriosus. The systemic organs must equally and quickly adjust to the dramatic increase in blood pressure and oxygen exposure. Similarly, intrauterine thermostability must be replaced by neonatal thermoregulation with its inherent increase in oxygen consumption.Approximately 85% of babies born at term will initiate spontaneous respirations within 10 to 30 seconds of birth, an additional 10% will respond during drying and stimulation, approximately 3% will initiate respirations after positive-pressure ventilation (PPV), 2% will be intubated to support respiratory function, and 0.1% will require chest compressions and/or epinephrine to achieve this transition. [1][2][3] Although the vast majority of newborn infants do not require intervention to make these transitional changes, the large number of births worldwide means that many infants require some assistance to achieve cardiorespiratory stability each year.Newly born infants who are breathing or crying and have good tone immediately after birth must be dried and kept warm so as to avoid hypothermia. These actions can be provided with the baby lying on the mother's chest and should not require separation of mother and baby. This does not preclude the need for clinical assessment of the baby. For the approximately 5% of newly born infants who do not initiate respiratory effort after stimulation by drying, and providing warmth to avoid hypothermia, 1 or more of the following actions should be undertaken: providing effective ventilation with a face mask or endotracheal intubation, and administration of chest compressions with or without intravenous medications or volume expansion for those with a persistent heart rate less than 60/min or asystole, despite strategies to achieve effective ventilation (Figure 1).The 2 vital signs that are used to identify the need for an intervention as well as to assess the response to interventions are heart rate and respirations. Progression down the algorithm should proceed only after successful completion of each step, the most critical being effective ventilation. A period of only approximately 60 seconds after birth is allotted to complete each of the first 2 steps, ie, determination of heart rate and institution of effective ventilation. Subsequent progression to the next step will depend o...

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations (CoSTR) for neonatal life support includes evidence from 7 systematic reviews, 3 scoping reviews, and 12 evidence updates. The Neonatal Life Support Task Force generally determined by consensus the type of evidence evaluation to perform; the topics for the evidence updates followed consultation with International Liaison Committee on Resuscitation member resuscitation councils. The 2020 CoSTRs for neonatal life support are published either as new statements or, if appropriate, reiterations of existing statements when the task force found they remained valid. Evidence review topics of particular interest include the use of suction in the presence of both clear and meconium-stained amniotic fluid, sustained inflations for initiation of positive-pressure ventilation, initial oxygen concentrations for initiation of resuscitation in both preterm and term infants, use of epinephrine (adrenaline) when ventilation and compressions fail to stabilize the newborn infant, appropriate routes of drug delivery during resuscitation, and consideration of when it is appropriate to redirect resuscitation efforts after significant efforts have failed. All sections of the Neonatal Resuscitation Algorithm are addressed, from preparation through to postresuscitation care. This document now forms the basis for ongoing evidence evaluation and reevaluation, which will be triggered as further evidence is published. Over 140 million babies are born annually worldwide ( https://ourworldindata.org/grapher/births-and-deaths-projected-to-2100 ). If up to 5% receive positive-pressure ventilation, this evidence evaluation is relevant to more than 7 million newborn infants every year. However, in terms of early care of the newborn infant, some of the topics addressed are relevant to every single baby born.