PMID- 32350538
OWN - NLM
STAT- MEDLINE
DCOM- 20210329
LR  - 20210329
IS  - 1930-613X (Electronic)
IS  - 0026-4075 (Linking)
VI  - 185
IP  - 7-8
DP  - 2020 Aug 14
TI  - Intrathoracic Pressure Regulator Performance in the Setting of Hemorrhage and 
      Acute Lung Injury.
PG  - e1083-e1090
LID - 10.1093/milmed/usz485 [doi]
AB  - INTRODUCTION: Intrathoracic pressure regulation (ITPR) can be utilized to enhance 
      venous return and cardiac preload by inducing negative end expiratory pressure in 
      mechanically ventilated patients. Previous preclinical studies have shown 
      increased mean arterial pressure (MAP) and decreased intracranial pressure (ICP) 
      with use of an ITPR device. The aim of this study was to evaluate the hemodynamic 
      and respiratory effects of ITPR in a porcine polytrauma model of hemorrhagic 
      shock and acute lung injury (ALI). METHODS: Swine were anesthetized and underwent 
      a combination of sham, hemorrhage, and/or lung injury. The experimental groups 
      included: no injury with and without ITPR (ITPR, Sham), hemorrhage with and 
      without ITPR (ITPR/Hem, Hem), and hemorrhage and ALI with and without ITPR 
      (ITPR/Hem/ALI, Hem/ALI). The ITPR device was initiated at a setting of -3 cmH2O 
      and incrementally decreased by 3 cmH2O after 30 minutes on each setting, with 
      15 minutes allowed for recovery between settings, to a nadir of -12 cmH2O. 
      Histopathological analysis of the lungs was scored by blinded, independent 
      reviewers. Of note, all animals were chemically paralyzed for the experiments to 
      suppress gasping at ITPR pressures below -6 cmH2O. RESULTS: Adequate shock was 
      induced in the hemorrhage model, with the MAP being decreased in the Hem and 
      ITPR/Hem group compared with Sham and ITPR/Sham, respectively, at all time points 
      (Hem 54.2 +/- 6.5 mmHg vs. 88.0 +/- 13.9 mmHg, p < 0.01, -12 cmH2O; ITPR/Hem 
      59.5 +/- 14.4 mmHg vs. 86.7 +/- 12.1 mmHg, p < 0.01, -12 cmH2O). In addition, the 
      PaO2/FIO2 ratio was appropriately decreased in Hem/ALI compared with Sham and Hem 
      groups (231.6 +/- 152.5 vs. 502.0 +/- 24.6 (Sham) p < 0.05 vs. 463.6 +/- 10.2, (Hem) 
      p < 0.01, -12 cmH2O). Heart rate was consistently higher in the ITPR/Hem/ALI 
      group compared with the Hem/ALI group (255 +/- 26 bpm vs. 150.6 +/- 62.3 bpm, -12 
      cmH2O) and higher in the ITPR/Hem group compared with Hem. Respiratory rate 
      (adjusted to maintain pH) was also higher in the ITPR/Hem/ALI group compared with 
      Hem/ALI at -9 and - 12 cmH2O (32.8 +/- 3.0 breaths per minute (bpm) vs. 
      26.8 +/- 3.6 bpm, -12 cmH2O) and higher in the ITPR/Hem group compared with Hem at 
      -6, -9, and - 12 cmH2O. Lung compliance and end expiratory lung volume (EELV) 
      were both consistently decreased in all three ITPR groups compared with their 
      controls. Histopathologic severity of lung injury was worse in the ITPR and ALI 
      groups compared with their respective injured controls or Sham. CONCLUSION: In 
      this swine polytrauma model, we demonstrated successful establishment of 
      hemorrhage and combined hemorrhage/ALI models. While ITPR did not demonstrate a 
      benefit for MAP or ICP, our data demonstrate that the ITPR device induced 
      tachycardia with associated increase in cardiac output, as well as tachypnea with 
      decreased lung compliance, EELV, PaO2/FIO2 ratio, and worse histopathologic lung 
      injury. Therefore, implementation of the ITPR device in the setting of polytrauma 
      may compromise pulmonary function without significant hemodynamic improvement.
CI  - (c) The Author(s) 2020. Published by Oxford University Press on behalf of the 
      Association of Military Surgeons of the United States. All rights reserved. For 
      permissions, please e-mail: journals.permissions@oup.com.
FAU - Morris, Mackenzie C
AU  - Morris MC
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
FAU - Niziolek, Grace M
AU  - Niziolek GM
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
FAU - Blakeman, Thomas C
AU  - Blakeman TC
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
FAU - Stevens-Topie, Sabre
AU  - Stevens-Topie S
AD  - Airman Systems Directorate, 711 Human Performance Wing, Wright Patterson AFB, 
      Dayton, OH 45229.
FAU - Veile, Rosalie
AU  - Veile R
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
FAU - Heh, Victor
AU  - Heh V
AD  - Airman Systems Directorate, 711 Human Performance Wing, Wright Patterson AFB, 
      Dayton, OH 45229.
FAU - Zingarelli, Basilia
AU  - Zingarelli B
AD  - Division of Critical Care Medicine, Cincinnati Children's Hospital Medical 
      Center, 3333 Burnet Avenue, Location B, 5th Floor, Cincinnati, OH.
FAU - Rodriquez, Dario
AU  - Rodriquez D
AD  - Airman Systems Directorate, 711 Human Performance Wing, Wright Patterson AFB, 
      Dayton, OH 45229.
FAU - Branson, Richard D
AU  - Branson RD
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
FAU - Goodman, Michael D
AU  - Goodman MD
AD  - Department of Surgery, University of Cincinnati, 231 Albert Sabin Way ML, 
      Cincinnati, OH 0558.
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - England
TA  - Mil Med
JT  - Military medicine
JID - 2984771R
SB  - IM
MH  - *Acute Lung Injury/complications
MH  - Animals
MH  - Blood Pressure
MH  - Cardiac Output
MH  - Heart Rate
MH  - Lung
MH  - Lung Compliance
MH  - Swine
EDAT- 2020/05/01 06:00
MHDA- 2021/03/30 06:00
CRDT- 2020/05/01 06:00
PHST- 2020/05/01 06:00 [pubmed]
PHST- 2021/03/30 06:00 [medline]
PHST- 2020/05/01 06:00 [entrez]
AID - 5734972 [pii]
AID - 10.1093/milmed/usz485 [doi]
PST - ppublish
SO  - Mil Med. 2020 Aug 14;185(7-8):e1083-e1090. doi: 10.1093/milmed/usz485.