RESUMEN
Objective To explore the similarities and differences between finger photoplethysmogram (PPG) and CSI in monitoring the depth of anaesthesia in Chinese adults under general anaesthesia. Methods Ninety-three patients, ASA ⅠorⅡ, aged 20-67, under general anaesthesia were enrolled. Anaesthesia was induced with target-controlled infusion (TCI) of propofol. The initial TCI concentration of propofol was set at 0.5 mg·L-1 followed by increments of 0.5 mg·L-1 at 3-min interval until the score of Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS)reached 0. PPG and CSI were continuously monitored and their values were recorded every 2-4 seconds. MOAAS was recorded every 30 seconds to evaluate the sedation level in the study period. ResultsFor the periodfrom pre-induction to pre-intubation, the difference of photoplethysmogram amplitudevalues had statistical significance between level 4 and level 3, level 3 and level 2 of MOAAS (P<0.05). CSIvalues declined along with the decrease of MOAAS levels and were statistically different between every two neighboring levels of MOAAS (P < 0.05). Photoplethysmogram amplitude (PPGA) and pulse beat interval (PBI) values showed significant differences before and after intubation, pre- and post-incision (P < 0.05). Conclusions PPGA and PBI appear to be suitable to monitor the nociceptive component of balanced general anesthesia , while the CSI exhibits a good performance in monitoring the sedation or hypnotic component of balanced general anesthesia , thusthe combination of PPGA and CSI would benefit the monitoring of the adequacy of depth of anaesthesia.
RESUMEN
BACKGROUND: The second derivative of the finger photoplethysmogram (SDPTG) is an indicator of arterial stiffness. The present study was conducted to clarify the factor structure of indices of the SDPTG in combination with components of the metabolic syndrome (MetS), to elucidate the significance of the SDPTG among various cardiovascular risk factors. METHODS: The SDPTG was determined in the second forefinger of the left hand in 1,055 male workers (mean age, 44.2+/-6.4 years). Among 4 waves of SDPTG components, the ratios of the height of the "a" wave to that of the "b" and "d" waves were expressed as b/a and d/a, and used as SDPTG indices for the analysis. RESULTS: Principal axis factoring analysis was conducted using age, SDPTG indices, components of MetS, and the serum levels of C-reactive protein (CRP) and uric acid. Three factors were extracted, and the SDPTG indices were categorized in combination with age as the third factor. Metabolic components and the SDPTG indices were independently categorized. These three factors explained 44.4% of the total variation. Multiple logistic regression analysis revealed age, d/a, serum uric acid, serum CRP, and regular exercise as independent determinants of the risk of MetS. The odds ratios (95% confidence intervals) were 1.08 (1.04 to 1.11), 0.10 (0.01 to 0.73), 1.24 (1.06 to 1.44), 3.59 (2.37 to 5.42), and 0.48 (0.28 to 0.82), respectively. CONCLUSION: The SDPTG indices were categorized in combination with age, and they differed in characteristics from components of MetS or inflammatory markers. In addition, this cross-sectional study also revealed decrease of the d/a as a risk factor for the development of MetS.