Major Transport Events Research Articles

Safety of transport and retrieval of patients on extracorporeal membrane oxygenation during the peak of COVID-19 pandemic in the State of Qatar

Background: Transport and retrieval of patients on extracorporeal membrane oxygenation (ECMO) support can be hazardous with complications reported for up to 27% of patients1. Transport of COVID-19 patients on ECMO requires appropriate training, resource allocation, meticulous planning, effective communication and co-ordination. Strict adherence to infection control procedures and appropriate use of personal protective equipment is recommended2. The Extracorporeal Life Support Organisation registry reports 43% in-hospital mortality of COVID-19 patients supported on ECMO. This includes in-house and retrieval ECMO cases3. Methods: Between March 1st and September 30th 2020, 32 confirmed COVID-19 positive patients underwent peripheral cannulation followed by transportation to the Medical Intensive Care Unit (MICU) at Hamad General Hospital. Mobile ECMO is complex and time consuming. Following arrival at the bedside and thorough clinical assessment, the ECMO consultant may decline, recommend optimisation of the care provided, or opt for cannulation and initiation of ECMO. Cannulation can be performed at the bedside or in the operating room. Following stabilisation, the patient is transferred for computed tomography imaging and then transported by ambulance to hospital (Figure 1). Finally, another transfer from hospital entrance to the MICU takes place. All these phases pose risks for errors and complications unless vigilance, teamwork and continuous effective monitoring and co-ordination is observed. Patients were evaluated for age and severity of illness (Table 1). In addition, all major transport-related adverse events were reported and analysed. Major transport events are cardiac arrest, ECMO emergencies (membrane or mechanical failure, air embolism, accidental decannulation, or significant cannula dislodgement), significant arrhythmia, severe bleeding or cardio-respiratory instability, and vehicle breakdown/malfunction. Findings: The majority of our patients were critically ill with high probability of mortality as depicted by SOFA and APACHE2 score. 29 out of 32 patients were male. None of our patients suffered major complications during transportation. Conclusion: This small case series demonstrates transport and retrieval on ECMO for COVID-19 positive patients can be safely undertaken provided appropriate expertise, protocols and resources are used.

Impact of Southern California anthropogenic emissions on ozone pollution in the mountain states: Model analysis and observational evidence from space

AbstractThe impact of Southern California (SoCal) anthropogenic emissions on ozone (O3) in the mountain states in May 2010 is studied using the Sulfur Transport and Deposition Model. We identified two to six major transport events from SoCal to different subregions in the mountain states, with transport times of 0–2 days indicated by trajectories, time‐lag correlations, and forward/adjoint sensitivities. Based on forward sensitivity analysis, the contributions from SoCal anthropogenic emissions to the monthly mean daily maximum 8 h average (MDA8) surface O3 in the mountain states decrease with distance from SoCal, and they range from <1 ppbv (in Wyoming) to 15 ppbv (in western Arizona). These contributions show medium (>0.6) to strong (>0.8) positive correlations with the modeled total surface MDA8 O3. For the most strongly affected states of Arizona and New Mexico, these contributions have median values of ~3, ~2, ~5, and ~15 ppbv when the total surface MDA8 O3 exceeded thresholds of 60, 65, 70, and 75 ppbv, respectively. Surface MDA8 O3 values in SoCal show strong nonlinear responses to varied magnitudes of perturbation (e.g., ±50% and 100%) in SoCal anthropogenic emissions and weak nonlinear responses in the mountain states. Case studies show that different scales of transport (e.g., trans‐Pacific, stratospheric intrusions, and interstate) can be dynamically and chemically coupled and simultaneously affect O3 in the mountain states when the meteorological conditions are favorable. During some of these strong transport periods, the contributions of SoCal anthropogenic emissions to hourly O3 in the mountain states can exceed 20 ppbv, close to the magnitude during a summer event reported by Langford et al. (2010). Satellite observations from the Tropospheric Emission Spectrometer and the Measurements of Pollution in the Troposphere multispectral retrievals qualitatively demonstrate large and interstate scales of transport, respectively. Suggestions are made for future satellite missions to measure O3 with improved spatial coverage, temporal frequency, and near‐surface sensitivity to provide better observational constraints on interstate pollution transport studies.

Evaluating chemical transport models: Comparison of effects of different CFC‐11 emission scenarios

In this study we compare the results of model simulations of CFC‐11 in the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM2) with two different published emission distributions. We find that for predicted CFC‐11 concentrations at the Atmospheric Lifetime Experiment/Global Atmospheric Gases Experiment (ALE/GAGE) observation sites there is very little difference resulting from the two distributions. However, the difference is apparent in major transport events such as pollution events. This has important implications for assessment of regional emissions from a sparse network like ALE/GAGE using inverse methods. It also implies that differences between modeled and observed CFC‐11 concentrations are due predominantly to model transport errors not model emission errors.

Acoustic backscatter measurements of suspended sediments as part of the 1988 STRESS experiment

As part of the 1988 STRESS (Sediment Transport Events on Shelves and Slopes) experiment, an upward looking 1‐MHz backscatter sonar was deployed in 90 m of water off the California coast for a period of 2 months. Dubbed “ABSS” (Acoustic Back Scatter System), this instrument made vertical profiles of the suspended sediment from 1.5 to 27.O m above bottom. Temporal sampling allowed both slow (every half‐hour) sampling to look at the long time evolution of the bottom boundary layer and fast (0.5 Hz over 2 min) sampling to look at individual wave‐induced suspension. During the course of the development, two major transport events (storms) were seen. in this talk, the ABSS measurement results, the correlation of the suspended sediment profiles obtained to relevant environmental variables, the correlation of the acoustic data to other measurement techniques (e,g., OBS, transmissometer), and the ramifications for coastal boundary layer monitoring are discussed. [Work supported by ONR.]