Pulse oximetry-derived pleth variability index can predict dexmedetomidine-induced changes in blood pressure in spontaneously breathing patients.
OBJECTIVE
Hypertension or hypotension in patients receiving continuous infusions of dexmedetomidine (DEX) is often due to changes in vascular resistance caused by α2 receptor stimulation. We investigated whether baseline perfusion index (PI) and pleth variability index (PVI), derived from pulse oximetry readings, could predict DEX-induced changes in the hemodynamic status in spontaneously breathing patients.


METHODS
Observational study.


METHODS
Operating room.


METHODS
Patients (American Society of Anesthesiologists performance status 1 or 2) scheduled to undergo lower extremity or abdominal procedures under regional anesthesia were approached.


METHODS
The PI and PVI were set as baseline upon arrival in theater and were then measured at 2.5-minute intervals. Upon attaining stable hemodynamic status under spontaneous breathing, intravenous administration of DEX was initiated at 6 μg kg(-1) h(-1) for 10minutes, followed by continuous infusion at 0.6 μg kg(-1) h(-1).


METHODS
Blood pressure, heart rate, PI, and PVI were measured. Hypertension was defined as an increase in systolic blood pressure (SBP) >15% and hypotension as a decrease in SBP <15% from baseline.


RESULTS
Baseline PI and PVI correlated with the degree of change in SBP. The maximum percentage increase as well as the maximum percentage of decrease in SBP from baseline correlated with baseline PI (r=0.418 [P=.005] and r=0.507 [P<.001], respectively) and PVI (r=-0.658 [P<.001] and r=-0.438 [P=.003], respectively). PVI <15 identified DEX-induced hypertension (sensitivity 94%, specificity 85%) and PVI >16 identified DEX-induced hypotension (sensitivity 83%, specificity 64%).


CONCLUSIONS
PVI may predict DEX-induced changes in blood pressure in spontaneously breathing patients.
Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 788-510, Japan. Electronic address: satomako@asahikawa-med.ac.jp.
Makoto
M
Sato
Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 788-510, Japan. Electronic address: taka.kunisawa@nifty.ne.jp.
Takayuki
T
Kunisawa
Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 788-510, Japan. Electronic address: work96@mac.com.
Atsushi
A
Kurosawa
Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 788-510, Japan. Electronic address: sasakawa@asahikawa-med.ac.jp.
Tomoki
T
Sasakawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000139:chemically induced* / Q000453:epidemiology; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000009:adverse effects; D007022:Hypotension / Q000139:chemically induced* / Q000453:epidemiology; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D010991:Plethysmography / Q000379:methods; D012680:Sensitivity and Specificity
D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine
Blood pressure; Dexmedetomidine; Pleth variability index