"Altered Short-Term Dynamics of Cardio-Respiratory Interaction during Propofol-Induced Yawning".

"Cardiac and respiratory oscillations have been shown to interact with each other. This interaction could reflect autonomic nervous system functionality. Propofol-induced yawning during anesthesia induction seems to be associated with sympathetic activation. Presumptively, there is high linearity among interaction of different physiologic system behaviors. Recently, investigators used coherence analysis to quantify the existence and strength of linearity between system signals for study of cardio-respiratory interaction under different physiological conditions. In this investigation, we used a method of time-frequency coherence function to analyze ECG and respiration signals to investigate the linearity of cardio-respiratory dynamics in patients undergoing routine propofol induction procedures for elective surgery. In this prospective, observational clinical study, a total of 84 eligible patients were enrolled. The patients were categorized into yawning and no-yawning groups during propofol induction. During induction, both groups demonstrated significant reduction in high frequency coherence (coh-HF) with simultaneously significant increase in very low frequency coherence (coh-VLF) compared to the pre-induction period. As yawning occurred, the yawning group had more significant changes of cardio-respiratory coherences than the no-yawning group at coh-LF and coh-VLF bands. The yawning group also showed loss of linearity at high frequency band (coh-HF > 0.5) as compared with the pre-induction period, and also showed increases in linearity at low (coh-LF > 0.5) and very low (coh-VLF > 0.5) frequency bands compared with the no-yawning group. Propofol-induced yawning alters cardio-respiratory dynamics with changes of linearity between cardio-vascular and respiratory system behaviors."

Clinical assessment of propofol-induced yawning with heart rate variability: a pilot study.

STUDY OBJECTIVES: To investigate the proportion of propofol-induced yawning and sympathovagal balance during propofol-induced yawning. DESIGN: Prospective, observational, clinical study. SETTING: University hospital and 2400-bed tertiary medical center. PATIENTS: 546 ASA physical status I and II patients undergoing elective surgery with general anesthesia. INTERVENTIONS: Standard induction of anesthesia was performed with intravenous (IV) propofol two to four mg/kg (group P), or pretreatment with atropine 0.1 mg/kg (group AP) or with fentanyl 1 to 3 microg/kg (group FP) before propofol. Continuous standard electrocardiogram for heart rate variability (HRV) was performed in another 20 patients to investigate sympathovagal balance during propofol-induced yawning. MEASUREMENTS AND MAIN RESULTS: The proportions of yawning were 53.5% (207/386), 61.1% (55/90), and 0% (0/50) in the P, AP, and FP groups, respectively. Propofol-induced yawning could be dramatically decreased by pretreatment with IV fentanyl (P < 0.001, chi2 test). Significant increased ratio of low-frequency/high-frequency power was detected during HRV monitoring in 9 patients with yawning in comparison with 11 patients without yawning (P < 0.05, Wilcoxon signed-rank test). CONCLUSIONS: Pretreatment with fentanyl may inhibit propofol-induced yawning. Fluctuations in autonomic function have been noted during propofol-induced yawning.

Postoperative paraplegia as a result of undiagnosed primitive neuroectodermal tumor, not epidural analgesia.

Postoperative paraplegia is a rare complication after epidural analgesia and often occurs with spinal hematoma or cord injury. We present the case of a 16-year-old girl who suffered from a tumor mass in the neck and abdomen who underwent gynecologic operation. Preoperatively, liver metastasis was found by computed tomography. Pathologic findings revealed that the abdominal mass was an ovarian dermoid cyst. After the operation, the patient complained of paraplegia while receiving epidural analgesia for postoperative pain control. A peripheral primitive neuroectodermal tumor in the thoracic and lumbar spines with spinal cord compression was later detected using magnetic resonance imaging. Learning from this case, we suggest that when a patient is preoperatively diagnosed with tumor metastasis, back pain and soreness, spinal cord compression from tumor metastasis should be excluded before epidural analgesia is implemented.

Are P values and statistical assessments in poster abstracts presented at annual meetings of Taiwan Society of Anesthesiologists relative to the characteristics of hospitals?

BACKGROUND: Many anesthesiologists in medical centers (MC) or in anesthesiologist-training hospitals (ATH) are accustomed to present their research data in the form of poster abstracts at the annual meetings of Taiwan Society of Anesthesiologists (TSA) to represent their academic gainings in a designated period of time. However, an orphaned P value without mentioning the related specified statistical test has frequently been found in these articles. The difference in presentation of statistical test after P value between MC/ATH and non-MC/non-ATH in recent three TSA consecutive annual meetings was explored in this article. METHODS: We collected the proceedings handbooks of TSA annual meetings in a period spanning 3 yrs (2003 to 2005) and analyzed the hospital characteristic of first institute-byliner in the poster abstract. Data were analyzed with Fisher's exact test and statistical significance was assumed if P < 0.05. RESULTS: Included were 101 poster abstracts with byliners of 20 hospitals. Only 2 of the 20 hospitals were accredited as non-ATH and 4 as non-MC. There were 64 (63%) abstracts without specified statistical test after P value and no significant difference was found among each category. (P = 0.47 in ATH vs. non-ATH and P = 0.07 in MC vs. non-MC). CONCLUSIONS: The basic concept of P value with specified statistical test was not applicable comprehensively in poster abstracts of the annual conferences. Based on our wishful intention, we suggest that the anesthesia administrators and senior anesthesiologists at ATH or MC, and the members of the committee responsible for running academic affairs in TSA, should pay attention to this prodigy and work together to improve our basic statistics in poster presentation.