To examine the hypothesis that the human pulmonary vascular response to hypoxia has a component with a slow time course, we measured pulmonary vascular resistance (PVR) in six healthy adult males during 8 h of isocapnic hypoxia. A balloon-tipped pulmonary artery catheter with thermistor was introduced via a forearm vein and used to derive PVR. The subjects were seated in a chamber in which the oxygen and carbon dioxide concentrations were adjusted to maintain an end-tidal Po2 of 50 Torr and an end-tidal Pco2 equal to the subject's normal prehypoxic value. PVR was measured before and at 0.5-h intervals during 8 h of hypoxia, the following 3 h of isocapnic euoxia (end-tidal Po2 100 Torr), and a subsequent 1-h reexposure to hypoxia. PVR rose from 1.23 +/- 0.26 (SE) Torr-min.1(-1) under euoxia [time (t) = 0] to 1.77 +/- 0.21 Torr.min.1(-1) at t = 0.5 h, reached a maximum at 2 h (2.91 +/- 0.33 Torr.min.1(-1)), and remained fairly constant between 2 and 8 h. Restoration of euoxia at 8 h led to a reduction in PVR with a slow component. Reexposure to hypoxia at 11 h resulted in a greater increase in PVR than at 1 h. Systemic vascular resistance had a similar slow component to its response, falling from 18.6 +/- 1.3 Torr.min.1(-1) at t = 0 to 17.3 +/- 1.4 Torr.min.1(-1) at t = 0.5 h, 14.4 +/- 0.6 Torr.min.1(-1) at t = 4 h, and 13.8 +/- 0.8 Torr.min.1(-1) at t = 8 h. The human pulmonary and systemic vascular responses to hypoxia extend over at least several hours.

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Correctional populations have an elevated human immunodeficiency virus (HIV) prevalence, yet many individuals lack access to subspecialty care. Our study showed that HIV-infected inmates had significantly greater virologic suppression and higher CD4 T-lymphocyte counts when managed by a multidisciplinary team of subspecialists conducting clinics via telemedicine. In other studies, these outcomes have been associated with reductions on HIV-related morbidity and mortality, as well as HIV transmission.

PurposeDischarge from an intensive care unit (ICU) out of hours is common. We undertook a systematic review and meta-analysis to explore the association between time of discharge and mortality/ICU readmission.MethodsWe searched Medline, Embase, Web of Knowledge, CINAHL, the Cochrane Library and OpenGrey to June 2017. We included studies reporting in-hospital mortality and/or ICU readmission rates by ICU discharge “out-of-hours” and “in-hours”. Inclusion was limited to patients aged ≥ 16 years discharged alive from a non-specialist ICU to a lower level of hospital care. Studies restricted to specific diseases were excluded. We assessed study quality using the Newcastle Ottowa Scale. We extracted published data, summarising using a random-effects meta-analysis.ResultsOur searches identified 1961 studies. We included unadjusted data from 1,191,178 patients from 18 cohort studies (presenting data from 1994 to 2014). “Out of hours” had multiple definitions, beginning between 16:00 and 22:00 and ending between 05:59 and 09:00. Patients discharged out of hours had higher in-hospital mortality [relative risk (95% CI) 1.39 (1.24, 1.57) p < 0.0001] and readmission rates [1·30 (1.19, 1.42), p < 0.001] than patients discharged in hours. Heterogeneity was high (I2 90.1% for mortality and 90.2% for readmission), resulting from differences in effect size rather than the presence of an effect.ConclusionsOut-of-hours discharge from an ICU is strongly associated with both in-hospital death and ICU readmission. These effects persisted across all definitions of “out of hours” and across healthcare systems in different geographical locations. Whether these increases in mortality and readmission result from patient differences, differences in care, or a combination remains unclear.Electronic supplementary materialThe online version of this article (10.1007/s00134-018-5245-2) contains supplementary material, which is available to authorized users.