The validity of the static-charge-sensitive bed in the detection of fentanyl-induced respiratory depression.
BACKGROUND
Only a few methods for the measurement of breathing are non-invasive and do not interfere with measured parameters. The static-charge-sensitive bed (SCSB) could be such a monitor. The aim of this study was to evaluate the validity of the SCSB compared with the respiratory inductive plethysmograph (RIP) using a fentanyl-induced respiratory depression model.


METHODS
Eight healthy male volunteers were infused with intravenous (i.v.) fentanyl (15 microg/kg/h) until a decrease in SpO2 below 90% for 1 min emerged. Breathing was continuously and simultaneously measured with SCSB and RIP. Oxygenation, hemodynamics, arterial blood gas analysis, and subjective opioid-related effects were monitored. Fentanyl concentration was measured from an arterial blood sample. The respiratory rate data of the SCSB (automated analysis and manual calculation) were compared with the corresponding RIP data, using analysis of variance for repeated measures. The validity of the SCSB compared with RIP was evaluated using an intra-class correlation coefficient.


RESULTS
Mean fentanyl dose was 629 microg. A statistically significant association was found between the RIP and SCSB data in the manual SCSB analysis (P < 0.0001), but not in the automated SCSB analysis (P = 0.91). After adjusting for the effect of time and the SCSB method, an intra-class correlation coefficient between the manually calculated SCSB values and the RIP values was 0.66.


CONCLUSIONS
Clinically significant changes in respiratory rate were detected with the SCSB, but the results had to be analyzed manually. The SCSB best suits situations, where comprehensive data are needed. It is not suitable for on-line respiratory monitoring, as the automated analysis did not calculate the respiratory rate correctly.
Department of Anesthesiology and Intensive Care, Turku University Hospital, Turku, Finland. eeva.nikkola@hus.fi
E M
EM
Nikkola
K A
KA
Leino
R S K
RS
Takala
O A
OA
Kirvelä
M A O
MA
Salonen
D000328:Adult; D000701:Analgesics, Opioid / Q000009:adverse effects*; D000704:Analysis of Variance; D001513:Beds / Q000145:classification*; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D005283:Fentanyl / Q000009:adverse effects*; D006801:Humans; D008297:Male; D009862:Online Systems; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects; D010108:Oxyhemoglobins / Q000032:analysis; D010991:Plethysmography / Q000379:methods; D015203:Reproducibility of Results; D012119:Respiration / Q000187:drug effects; D012131:Respiratory Insufficiency / Q000139:chemically induced* / Q000175:diagnosis
D000701:Analgesics, Opioid; D010108:Oxyhemoglobins; D002245:Carbon Dioxide; D010100:Oxygen; D005283:Fentanyl