The Science Journal of the American Association for Respiratory Care

2001 OPEN FORUM Abstracts

Sedation and neuromuscular blocking agent (NMBA) requirements during initiation of low VT ventilation in patients with acute lung injury (ALI)

RH Kallet, MS RRT, M Eisner MD, JM Luce MD. NHLBI ARDS Clinical Trials Networkat San Francisco General Hospital (SFGH)

Background: Theamount of sedation and use of NMBA required to treat respiratory distress and/orpatient-ventilator dyssynchrony (distress/dyssynchrony) during low VTventilation is unknown. Methods: The medical records of all 43 patients enrolledinto the ARDS Network low VT study at SFGH and randomized to eitherlow VT (6mL/kg) or traditional VT (12 mL/kg) ventilationwere reviewed retrospectively to determine both sedation/NMBA use, and the incidenceof distress/ dyssynchrony during the first 24 h of protocol management. Totalsedation requirements and Ramsey sedation scores were calculated. All analgesicsand sedatives were converted to fentanyl and lorazepam equivalents and expressedin mg/day.1 Data was expressed as mean (± standard deviation) andcomparisons were made using Mann-Whitney tests. NMBA use was assessed by two-sidedFisher?s Exact test. Alpha was set at 0.05.

Results: Distress/dyssynchrony was documented in 67% (14/21) of the patients in the low VTgroup, and in the 36% (8/22) of the patients randomized to traditional VT.Yet the total amount of analgesics and sedatives administered were not different.A trend towards higher NMBA use was found in the 12 mL/kg VT group(relative risk = 1.64; p = 0.24). NMBA?s were administered prior to enrollmentin all 6 patients in the 12 mL/kg VT group, and after enrollmentin both patients in the 6 mL/kg VT group. When sedation/analgesicrequirements were assessed in each VT group based upon the presenceof distress/ dyssynchrony, only the benzodiazepam dosages were different inthe low VT group.

Low VTTraditionalVTp
Fentanyl (mg/d)2.7 ± 2.32.5 ± 2.40.55
Lorazepammg/d19.4 ± 10.617.5 ± 14.80.37
Propofol (g/d) 2.94 ± 1.632.70 ± 3.05 0.86
Baseline Ramsey3.5 ± 1.53.8 ± 1.60.42
Day 1 Ramsey4.2 ± 1.63.6 ± 1.8 0.28
Low VT Group DyssynchronySynchronyp
Lorazepammg/d14.7 ± 1028.2 ± 4.60.007


Conclusion: Distress/dyssynchronywas higher in the low VT group despite equivalent administrationof sedatives/analgesics. This may suggest that higher levels of analgesics/sedatives(particularly benzodiazepams) may be required to treat distress/dys-synchronyduring low VT ventilation. However, the trend towards higher NMBAuse in the traditional VT group may have masked the opportunity todetect distress/dyssynchrony.

1. Cammarrano WB, etal. Acute withdrawl syndrome realted to the administration of analgesic andsedative medications in adult intensive care unit patients. Crit Care Med. 1998;26(4): 676-684. (NIH R01-HL51856)


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