Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitor... more Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitoring of intubated patients in EMS. Previous work has explored the use of ETCO2 monitoring in non-intubated patients with sensors placed in the nares. However, little is known about the effect of passive O2 delivery [nasal cannula (NC) or high-flow, non-rebreather mask (NRB)] on ETCO2 measurement. Objective: To compare ETCO2 measurements in non-intubated Traumatic Brain Injury (TBI) patients receiving O2 via NC vs. NRB in the field. Methods: A subset of cases from the EPIC EMS TBI Study (NIH-1R01NS071049) were evaluated (4/13-4/18). Non-intubated cases from 5 EMS agencies providing monitor data, including continuous ETCO2. Start and end segments were excluded to remove artifact from initiation (“ramp-up”) or termination of monitoring. Statistics: Wilcoxon rank-sum test, two-sample t-test, and Chi-squared test were used as appropriate. Linear regression compared continuous variables in adju...
Background: It is well established that prehospital hypoxia dramatically increases mortality in T... more Background: It is well established that prehospital hypoxia dramatically increases mortality in Traumatic Brain Injury (TBI). Thus, in EMS TBI research, case ascertainment and risk-adjustment are highly dependent upon documentation of in-field O2 saturation. Objective: To compare the rate of hypoxia identified by EMS personnel and documented in EMS patient care records (PCR) vs the actual rate of hypoxia recorded by continuous, non-invasive monitor in TBI. Methods: A subset of major TBI cases (moderate/severe) in the EPIC EMS TBI Study (NIH 1R01NS071049) were evaluated (3/30/13-6/26/15). Cases from 4 EMS agencies that report continuous monitor data (Philips MRx™) as part of EPIC were included. All monitor data available for post-hoc review were displayed and accessible to the providers during EMS care. We compared PCR documentation of hypoxia (O2 sat <90%) to actual recorded monitor data on each patient (Fisher’s Exact Test; α=0.05). Results: 77 cases were included [median age: 5...
The development and testing of incident detection algorithms was based on Los Angeles and Minneap... more The development and testing of incident detection algorithms was based on Los Angeles and Minneapolis freeway surveillance data. Algorithms considered were based on times series and pattern recognition techniques. Attention was given to the effects of geometrics, sensor configuration and weather, and methods were developed for detection malfunctioning sensors and for identifying the lane of an incident. This, the fourth volume, contains documentation of programs which can be implemented to provide the incident detection function in a real-time system, and programs which can be used for evaluating and calibrating incident detection algorithms. /FHWA/
Background: Recent studies have shown that the lowest prehospital systolic blood pressure (SBP) i... more Background: Recent studies have shown that the lowest prehospital systolic blood pressure (SBP) is strongly associated with mortality across a remarkably wide range (far above 90 mmHg) in traumatic...
Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitor... more Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitoring of intubated patients in many emergency care settings, including EMS. Previous work has explored the use of ETCO2 monitoring in non-intubated patients with sensors placed in the nares. However, nothing is known about the effect of passive oxygen delivery [nasal cannula (NC) or non-rebreather mask (NRB)] on ETCO2 measurement. Objective: To compare ETCO2 measurements in non-intubated Traumatic Brain Injury (TBI) patients receiving O2 via NC vs NRB in the prehospital setting. Methods: A subset of major TBI cases (CDC Barell Matrix Type-1) in the Excellence in Prehospital Injury Care (EPIC) TBI Study (NIH/NINDS-1R01NS071049; ClinicalTrials.gov-NCT01339702) were evaluated 4/13-3/17). Non-intubated cases from 6 EMS agencies providing monitor data (Philips MRx) were included when continuous ETCO2 data were available. Statistics: Two-tailed t test, α = 0.05. Results: The 104 included cases h...
Objective: Little is known about End-Tidal CO 2 monitoring using nasal cannula sensors (NC-CO 2 )... more Objective: Little is known about End-Tidal CO 2 monitoring using nasal cannula sensors (NC-CO 2 ) in non-intubated patients. Objective: To describe the patterns of NC-CO 2 seen during the EMS care of spontaneously breathing major Traumatic Brain Injury (TBI) patients. Methods: Continuous NC-CO 2 data (Philips MRx™ monitors) were evaluated from non-intubated, major (moderate, severe, critical) TBI cases (4/13-5/17) in the EPIC TBI Study (NIH 1R01NS071049). Descriptive statistics were used to evaluate case and NC-CO 2 attributes. Results: Included were 92 cases [median age = 50 (range 10-91; 66% male)]. Median respiratory rate (RR) was >15/min in 87% of cases and >20/min in 53%. The highest median RR was 39. Sixteen cases (17%) had a median NC-CO 2 <20 mmHg, 37% (34) were 20-29, 18% (17) were 30-34, 25% (23) were 35-45. Two cases (2%) were 45-50, which has not been noted in this population previously. No case had a median NC-CO 2 >50. Several common NC-CO 2 patterns emerge...
Background: Studies show that EMS patients are often inadvertently hyperventilated (HV), resultin... more Background: Studies show that EMS patients are often inadvertently hyperventilated (HV), resulting in hypocapnia. In TBI, HV markedly increases mortality. We evaluated continuous prehospital ETCO2 data in intubated TBI patients. Methods: Analysis of monitor data files (Philips MRx™) from a sample of intubated TBI cases in the EPIC Study (NIH-R01NS071049). Results: Among hundreds of cases, graphical display of continuous ETCO2 from 3 subjects dramatically exemplified commonly-occurring inadvertent HV. Fig 1 shows unrecognized HV lasting nearly 15 min. Fig 2 reveals nearly 14 min of increasing ventilatory rate and progressively worsening hypocapnia. Fig 3 shows nearly 4 min of HV that ends abruptly with clear, sudden recognition and slowing of ventilatory rate that leads to restoration of normal ETCO2 in only a few breaths. The corresponding EMS patient care records (PCR) failed to document the presence, severity, and duration of HV. Conclusions: In a study emphasizing prevention of H...
Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitor... more Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitoring of intubated patients in EMS. Previous work has explored the use of ETCO2 monitoring in non-intubated patients with sensors placed in the nares. However, little is known about the effect of passive O2 delivery [nasal cannula (NC) or high-flow, non-rebreather mask (NRB)] on ETCO2 measurement. Objective: To compare ETCO2 measurements in non-intubated Traumatic Brain Injury (TBI) patients receiving O2 via NC vs. NRB in the field. Methods: A subset of cases from the EPIC EMS TBI Study (NIH-1R01NS071049) were evaluated (4/13-4/18). Non-intubated cases from 5 EMS agencies providing monitor data, including continuous ETCO2. Start and end segments were excluded to remove artifact from initiation (“ramp-up”) or termination of monitoring. Statistics: Wilcoxon rank-sum test, two-sample t-test, and Chi-squared test were used as appropriate. Linear regression compared continuous variables in adju...
Background: It is well established that prehospital hypoxia dramatically increases mortality in T... more Background: It is well established that prehospital hypoxia dramatically increases mortality in Traumatic Brain Injury (TBI). Thus, in EMS TBI research, case ascertainment and risk-adjustment are highly dependent upon documentation of in-field O2 saturation. Objective: To compare the rate of hypoxia identified by EMS personnel and documented in EMS patient care records (PCR) vs the actual rate of hypoxia recorded by continuous, non-invasive monitor in TBI. Methods: A subset of major TBI cases (moderate/severe) in the EPIC EMS TBI Study (NIH 1R01NS071049) were evaluated (3/30/13-6/26/15). Cases from 4 EMS agencies that report continuous monitor data (Philips MRx™) as part of EPIC were included. All monitor data available for post-hoc review were displayed and accessible to the providers during EMS care. We compared PCR documentation of hypoxia (O2 sat <90%) to actual recorded monitor data on each patient (Fisher’s Exact Test; α=0.05). Results: 77 cases were included [median age: 5...
The development and testing of incident detection algorithms was based on Los Angeles and Minneap... more The development and testing of incident detection algorithms was based on Los Angeles and Minneapolis freeway surveillance data. Algorithms considered were based on times series and pattern recognition techniques. Attention was given to the effects of geometrics, sensor configuration and weather, and methods were developed for detection malfunctioning sensors and for identifying the lane of an incident. This, the fourth volume, contains documentation of programs which can be implemented to provide the incident detection function in a real-time system, and programs which can be used for evaluating and calibrating incident detection algorithms. /FHWA/
Background: Recent studies have shown that the lowest prehospital systolic blood pressure (SBP) i... more Background: Recent studies have shown that the lowest prehospital systolic blood pressure (SBP) is strongly associated with mortality across a remarkably wide range (far above 90 mmHg) in traumatic...
Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitor... more Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitoring of intubated patients in many emergency care settings, including EMS. Previous work has explored the use of ETCO2 monitoring in non-intubated patients with sensors placed in the nares. However, nothing is known about the effect of passive oxygen delivery [nasal cannula (NC) or non-rebreather mask (NRB)] on ETCO2 measurement. Objective: To compare ETCO2 measurements in non-intubated Traumatic Brain Injury (TBI) patients receiving O2 via NC vs NRB in the prehospital setting. Methods: A subset of major TBI cases (CDC Barell Matrix Type-1) in the Excellence in Prehospital Injury Care (EPIC) TBI Study (NIH/NINDS-1R01NS071049; ClinicalTrials.gov-NCT01339702) were evaluated 4/13-3/17). Non-intubated cases from 6 EMS agencies providing monitor data (Philips MRx) were included when continuous ETCO2 data were available. Statistics: Two-tailed t test, α = 0.05. Results: The 104 included cases h...
Objective: Little is known about End-Tidal CO 2 monitoring using nasal cannula sensors (NC-CO 2 )... more Objective: Little is known about End-Tidal CO 2 monitoring using nasal cannula sensors (NC-CO 2 ) in non-intubated patients. Objective: To describe the patterns of NC-CO 2 seen during the EMS care of spontaneously breathing major Traumatic Brain Injury (TBI) patients. Methods: Continuous NC-CO 2 data (Philips MRx™ monitors) were evaluated from non-intubated, major (moderate, severe, critical) TBI cases (4/13-5/17) in the EPIC TBI Study (NIH 1R01NS071049). Descriptive statistics were used to evaluate case and NC-CO 2 attributes. Results: Included were 92 cases [median age = 50 (range 10-91; 66% male)]. Median respiratory rate (RR) was >15/min in 87% of cases and >20/min in 53%. The highest median RR was 39. Sixteen cases (17%) had a median NC-CO 2 <20 mmHg, 37% (34) were 20-29, 18% (17) were 30-34, 25% (23) were 35-45. Two cases (2%) were 45-50, which has not been noted in this population previously. No case had a median NC-CO 2 >50. Several common NC-CO 2 patterns emerge...
Background: Studies show that EMS patients are often inadvertently hyperventilated (HV), resultin... more Background: Studies show that EMS patients are often inadvertently hyperventilated (HV), resulting in hypocapnia. In TBI, HV markedly increases mortality. We evaluated continuous prehospital ETCO2 data in intubated TBI patients. Methods: Analysis of monitor data files (Philips MRx™) from a sample of intubated TBI cases in the EPIC Study (NIH-R01NS071049). Results: Among hundreds of cases, graphical display of continuous ETCO2 from 3 subjects dramatically exemplified commonly-occurring inadvertent HV. Fig 1 shows unrecognized HV lasting nearly 15 min. Fig 2 reveals nearly 14 min of increasing ventilatory rate and progressively worsening hypocapnia. Fig 3 shows nearly 4 min of HV that ends abruptly with clear, sudden recognition and slowing of ventilatory rate that leads to restoration of normal ETCO2 in only a few breaths. The corresponding EMS patient care records (PCR) failed to document the presence, severity, and duration of HV. Conclusions: In a study emphasizing prevention of H...
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Papers by Eric Helfenbein