Publications by authors named "David Siskind"

4 Publications

  • Page 1 of 1

Absence of COVID-19 Disease Among Chronically Ventilated Nursing Home Patients.

J Am Med Dir Assoc 2021 12 29;22(12):2500-2503. Epub 2021 Sep 29.

NYU Long Island School of Medicine, Mineola, NY, USA; Department of Medicine, NYU Langone Hospital-Long Island, Mineola, NY, USA.

Objective: To describe the experience of COVID-19 disease among chronically ventilated and nonventilated nursing home patients living in 3 separate nursing homes.

Design: Observational study of death, respiratory illness and COVID-19 polymerase chain reaction (PCR) results among residents and staff during nursing home outbreaks in 2020.

Setting And Participants: 93 chronically ventilated nursing home patients and 1151 nonventilated patients living among 3 separate nursing homes on Long Island, New York, as of March 15, 2020. Illness, PCR results, and antibody studies among staff are also reported.

Measurements: Data were collected on death rate among chronically ventilated and nonventilated patients between March 15 and May 15, 2020, compared to the same time in 2019; prevalence of PCR positivity among ventilated and nonventilated patients in 2020; reported illness, PCR positivity, and antibody among staff.

Results: Total numbers of deaths among chronically ventilated nursing home patients during this time frame were similar to the analogous period 1 year earlier (9 of 93 in 2020 vs 8 of 100 in 2019, P = .8), whereas deaths among nonventilated patients were greatly increased (214 of 1151 in 2020 vs 55 of 1189 in 2019, P < .001). No ventilated patient deaths were clinically judged to be COVID-19 related. No clusters of COVID-19 illness could be demonstrated among ventilated patients. Surveillance PCR testing of ventilator patients failed to reveal COVID-19 positivity (none of 84 ventilator patients vs 81 of 971 nonventilator patients, P < .002). Illness and evidence of COVID-19 infection was demonstrated among staff working both in nonventilator and in ventilator units.

Conclusions And Implications: COVID-19 infection resulted in illness and death among nonventilated nursing home residents as well as among staff. This was not observed among chronically ventilated patients. The mechanics of chronic ventilation appears to protect chronically ventilated patients from COVID-19 disease.
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December 2021

Transport of Nitric Oxide Via Lagrangian Coherent Structures Into the Top of the Polar Vortex.

J Geophys Res Atmos 2021 Jun 28;126(11):e2020JD034523. Epub 2021 May 28.

Department of Physics Norwegian University of Science and Technology Norway.

The energetic particle precipitation (EPP) indirect effect (IE) refers to the downward transport of reactive odd nitrogen (NO = NO + NO) produced by EPP (EPP-NO) from the polar winter mesosphere and lower thermosphere to the stratosphere where it can destroy ozone. Previous studies of the EPP IE examined NO descent averaged over the polar region, but the work presented here considers longitudinal variations. We report that the January 2009 split Arctic vortex in the stratosphere left an imprint on the distribution of NO near the mesopause, and that the magnitude of EPP-NO descent in the upper mesosphere depends strongly on the planetary wave (PW) phase. We focus on an 11-day case study in late January immediately following the 2009 sudden stratospheric warming during which regional-scale Lagrangian coherent structures (LCSs) formed atop the strengthening mesospheric vortex. The LCSs emerged over the north Atlantic in the vicinity of the trough of a 10-day westward traveling planetary wave. Over the next week, the LCSs acted to confine NO-rich air to polar latitudes, effectively prolonging its lifetime as it descended into the top of the polar vortex. Both a whole atmosphere data assimilation model and satellite observations show that the PW trough remained coincident in space and time with the NO-rich air as both migrated westward over the Canadian Arctic. Estimates of descent rates indicate five times stronger descent inside the PW trough compared to other longitudes. This case serves to set the stage for future climatological analysis of NO transport via LCSs.
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June 2021

Policy Recommendations Regarding Skilled Nursing Facility Management of Coronavirus 19 (COVID-19): Lessons from New York State.

J Am Med Dir Assoc 2020 Jul 2;21(7):888-892. Epub 2020 Jun 2.

United Hebrew, New Rochelle, NY.

To provide policy recommendations for managing Coronavirus 19 (COVID-19) in skilled nursing facilities, a group of certified medical directors from several facilities in New York state with experience managing the disease used e-mail, phone, and video conferencing to develop consensus recommendations. The resulting document provides recommendations on screening, protection of staff, screening of residents, management of Coronavirus 19 positive and presumed positive cases, communication during an outbreak, management of admissions and readmissions, and providing emotional support for staff. These consensus guidelines have been endorsed by the Executive Board of the New York Medical Directors Association and the Board of the Metropolitan Area Geriatrics Society.
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July 2020

The Role of Vertically and Obliquely Propagating Gravity Waves in Influencing the Polar Summer Mesosphere.

J Geophys Res Atmos 2020 May 17;125(9). Epub 2020 Apr 17.

Center for Space Science and Engineering Research, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA.

Using an 8-year (2007-2014) data set from two different limb-viewing instruments, we evaluate the relative roles of vertically versus obliquely propagating gravity waves (GWs) as sources of GWs in the polar summer mesosphere. Obliquely propagating waves are of interest because they are presumed to be generated by the summer monsoons. In the high-latitude upper mesosphere, the correlation coefficient between the time series of ice water content (IWC) and GW amplitude is 0.48, indicating that the observed GWs enhance polar mesospheric clouds (PMCs). For vertically propagating waves, the correlation coefficient between IWC and stratospheric/lower mesospheric (20-70 km) GW amplitude at the same high latitudes becomes more negative with increasing altitude. This change in correlation from negative in the lower mesosphere to positive at PMC altitudes suggests the presence of another source of GWs. The positive correlation coefficient between the time series of IWC and GW amplitude from 0-50°N, 20-90 km shows a slanted structure suggesting oblique propagation. This slanted structure is more robust in some seasons compared to others, and this interannual variability may be due to the latitudinal gradient of the mesospheric easterly jet where steeper gradients allow for low-latitude tropospheric GWs to be refracted to the high-latitude mesosphere more efficiently. Gravity-Wave Regional or Global Ray Tracer (GROGRAT) ray tracing simulations show that more GWs propagate obliquely compared to vertically propagating waves that reach PMC altitudes. For obliquely propagating waves, GROGRAT simulations indicate that nonorographic tropospheric GWs with faster phase speed (>20 m/s) and longer horizontal wavelength (>400 km) have a higher probability of reaching the polar summer mesosphere.
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May 2020