Huey-Wen Yien

Spectral analysis of systemic arterial pressure and heart rate signals of patients with acute respiratory failure induced by severe organophosphate poisoning.

ObjectiveSpectral analysis of systemic arterial pressure (BP) and heart rate (HR) signals may be an alternative prognostic tool for predicting patient outcome in the intensive care unit (ICU). We evaluated the applicability of the same analysis in the emergency department for predicting mortality in patients with acute respiratory failure induced by severe organophosphate poisoning. DesignProspective collection of data from 14 emergency service patients. SettingEmergency service at a large, university-affiliated medical center. PatientsConsecutive patients who, after attempting suicide by ingesting organophosphates, were admitted to the ICU of the emergency service with acute respiratory failure and remained for ≥2 days InterventionsNone. Measurements and Main ResultsDemographic and survival data and day 1 Acute Physiology and Chronic Health Evaluation (APACHE) II and Glasgow Coma Scale scores were recorded. Continuous, on-line, real-time spectral analysis of BP and HR signals was carried out during the first 12 hrs after admission. We then computed the total sum of power density during this period of the low-frequency (0.04–0.15 Hz) and very low-frequency (0.004–0.04 Hz) components in the BP and HR spectra, along with the averaged values of mean BP and HR. Eight patients who recovered exhibited vigorous power in the low-frequency and very low-frequency components of their BP and HR signals. There was a significant reduction in the power density of those four spectral components in three patients who eventually died. Three patients discharged in a vegetative state manifested significantly reduced power in the low-frequency component in their BP spectra, with maintained power in the other three spectral components. APACHE II and Glasgow Coma Scale scores of the recovered patients were discernibly different from those of patients who eventually died or who became vegetative. None of the 14 patients showed appreciable differences in mean BP, mean HR, erythrocyte or plasma cholinesterase concentration, or atropine requirement during the first 24 hrs. ConclusionThe low-frequency and very low-frequency components of BP and HR signals may be a sensitive alternative index for early prediction of mortality in patients with acute respiratory failure induced by severe organophosphate poisoning.

Perioperative plasma concentrations of tumor necrosis factor-alpha and interleukin-6 in infected patients.

OBJECTIVE To characterize the sequential plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) and their relationship with the clinical outcome in patients with intra-abdominal infection who underwent surgical intervention. DESIGN A prospective, comparative study. SETTING Surgical intensive care unit of a university hospital. PATIENTS Fifteen patients with surgically proved intra-abdominal infection were included as the infected group. The comparative noninfected group consisted of ten patients who underwent major abdominal surgery without infection. INTERVENTIONS Blood samples were obtained from the indwelling arterial catheter before induction of general anesthesia, and 1, 1.5, 2, 3, 4, 6, and 24 hrs after skin incision. MEASUREMENTS AND MAIN RESULTS Plasma cytokine concentrations were measured using radioimmunoassay. The hemodynamic and physiologic parameters were recorded for comparison with cytokine concentrations. In the noninfected group, the TNF-alpha concentration was very low throughout the observation period, and the IL-6 concentration increased 4 hrs after skin incision. The infected group had significantly higher TNF-alpha and IL-6 concentrations than the noninfected group. The TNF-alpha concentration increased from 129.2 +/- 46.4 to 1196.0 +/- 445.8 pg/mL and the IL-6 concentration increased from 54.2 +/- 24.3 to 560.3 +/- 187.5 pg/mL 2 hrs after skin incision in the infected group. The postoperative APACHE II score correlated significantly with both peak IL-6 (r2=.39) and peak TNF-alpha (r2=.32) concentrations. CONCLUSIONS Both TNF-alpha and IL-6 concentrations increased significantly after surgical intervention in patients with intra-abdominal infection. The pulse increase in TNF-alpha concentration and the persistent increase in IL-6 concentration were related to the poor postoperative clinical condition in infected patients.

Information categorization approach to literary authorship disputes

Scientific analysis of the linguistic styles of different authors has generated considerable interest. We present a generic approach to measuring the similarity of two symbolic sequences that requires minimal background knowledge about a given human language. Our analysis is based on word rank order–frequency statistics and phylogenetic tree construction. We demonstrate the applicability of this method to historic authorship questions related to the classic Chinese novel “The Dream of the Red Chamber,” to the plays of William Shakespeare, and to the Federalist papers. This method may also provide a simple approach to other large databases based on their information content.

Oral clonidine premedication preserves heart rate variability for patients undergoing larparoscopic cholecystectomy.

Background: Clonidine has been shown to reduce perioperative circulatory instability. This postoperative analgesic effect of clonidine was also known in previous studies. The aim of the study was to investigate the clinical efficiency of oral clonidine premedication in anesthesia and analgesia in patients undergoing laparoscopic cholecystectomy.

Heart Rate Variability in Neonatal Rats After Perinatal Cocaine Exposure

Pregnant rats received saline once daily (Control QD) or twice daily (Control BID), cocaine 2 mg/kg IV daily (COC QD) or twice daily (COC BID) throughout gestation beginning on gestational day 4. The treatment was continued in nursing mothers until postnatal day 7. All studies were performed in their offsprings on postnatal days 1 and 7. An age-dependent increase in heart rate was observed from D1 to D7 in all four groups of animals. Cocaine exposure significantly increased heart rate in the once daily treatment group on D1 and D7. In contrast, twice daily cocaine exposure did not alter heart rate. Maturational changes in heart rate variability (HRV) were also documented. Low-frequency (LF: 0.25-0.8 Hz) power of HRV is a marker of both sympathetic and parasympathetic influences. and high-frequency (HF: 0.8-2.4 Hz) power is a marker of efferent vagal activity. Total power (TP) is the sum of LF and HF. TP, normalized units of LF (LF as percent of TP), and normalized HF power decreased from D1 to D7 in all groups. Cocaine treatment affected both LF and HF powers and there was an interaction between cocaine treatment and age for both LF and HF. Although LF/HF ratio decreased from D1 to D7 in both groups of control animals. LF/HF did not change from D1 to D7 in either cocaine-treated group. Thus, cocaine exposure significantly attenuated the age-dependent change in LF/HF. Our results indicated that there were normal developmental changes in HRV consistent with continued postnatal development of autonomic nervous system. Perinatal cocaine exposure appeared to modify these changes. The specific autonomic mechanism for the cocaine effect may be a decline in parasympathetic activity and a concomitant change in sympathetic activity.

Time‐varying spectral analysis revealing differential effects of sevoflurane anaesthesia: non‐rhythmic‐to‐rhythmic ratio

Heart rate variability (HRV) may reflect various physiological dynamics. In particular, variation of R‐R peak interval (RRI) of electrocardiography appears regularly oscillatory in deeper levels of anaesthesia and less regular in lighter levels of anaesthesia. We proposed a new index, non‐rhythmic‐to‐rhythmic ratio (NRR), to quantify this feature and investigated its potential to estimate depth of anaesthesia.

Instructor-based Real-time Multimedia Medical Simulation to Update Concepts of Difficult Airway Management for Experienced Airway Practitioners

Background: We integrated lecture, real‐time multimedia display and medical simulation into a new renewal airway management training protocol for experienced nurse anesthetists. Methods: Trainees of the Taiwan Association of Nurse Anesthetists from northern Taiwan and junior residents from our department were enrolled into the training program. A 4‐hour renewal curriculum in the management of airway emergen‐cies was developed, which consisted of a 2‐hour general lecture (including 4 divided sections) and a 2‐hour instructor‐based real‐time multimedia medical simulation of 4 specific techniques. After detailed explanation of each specific instrument at the beginning of each simulation, the instructors demonstrated accurate and successful management of 4 airway crises from clinical experience by using a standardized human patient simulator situated on the stage of the conference room. Meanwhile, real‐time display of instructors’ performance, responsive physical parameters and images from specific instruments were conducted by video camera and video processor, and projected on a 3‐frame screen. Brief summary and feedback were performed after each simulation. Trainees completed a questionnaire 6 months after they participated in the training program. Results: Two hundred and forty‐two nurse anesthetists and 13 young residents were trained with this protocol. The questionnaire revealed that the renewal training program was useful. Participants updated their knowledge of difficult airway management, gained more confidence, improved performance, and provided effective assistance in handling airway crises. Conclusion: Renewing practice guidelines and teaching airway management skills, especially for difficult airway crises and protection of personnel, continues to be an important issue. Instructor‐based real‐time multimedia simulation is a fast, useful and systematic renewal educational method for many participants with extensive experience of airway management to update their knowledge about difficult airway management, and acquire improved decision‐making and communication capabilities, skills of specific airway management. [J Chin Med Assoc 2008;71(4):174–179]

Analyzing autonomic activity in electrocardiography about general anesthesia by spectrogram with multitaper time-frequency reassignment

Autonomic nerve activities in human body under general anesthesia are dynamic and diverse. Respiratory sinus arrhythmia is associated with depth of anesthesia, which exists in the high-frequency region of RRI (beat-to-beat R-peak interval) spectrum. Analyzing RRI variation in electrocardiography by classical power spectrum is insufficient because of the lack of temporal resolution. To better understand autonomic activity during anesthesia, we used spectrogram of RRI to extract its instantaneous information. For improving visual resolution, we choose a newly developed technique, multitaper time-frequency reassignment (MTFR), to estimate spectrograms. The technique provides time-varying spectrogram for RRI with good performance in time-frequency resolution and low fluctuation. Real-life cases are used to demonstrate the variety of autonomic activity presented clearly by the MTFR spectrogram, compared with Gabor spectrogram. Their implications in depth of anesthesia are discussed.

Pseudomonas Cepacia Induced Septic Shock after Propofol-A Case Report

We report a healthy young female who developed septic shock and multiple organ failure soon after receiving a cosmetic surgery for augmentation of breasts under general anesthesia. Blood cultures yielded the growth of pseudomonas cepacia. We describe the clinical course and investigate the causes of the septic shock. Contamination of propofol, the intravenous anesthetic agent, was suspected.

Albumin Administration in Patients with Severe Sepsis Due to Secondary Peritonitis

Background: To determine whether or not intravenous administration of human albumin can reduce mortality in patients with severe sepsis due to secondary peritonitis. Methods: Adult patients who were admitted to the surgical intensive care unit (SICU) who fulfilled the criteria of severe sepsis due to secondary peritonitis were consecutively included in this retrospective study. Patients who received and those who did not receive at least a daily minimum of 25 g intravenous human albumin for 3 days during their first 7 days of SICU admission were classified as the study group and control group, respectively. Results: A total of 133 patients were included in this study. For patients with baseline serum albumin ≤ 20 g/L, 28‐day mortality was significantly lower in the study group. For patients with baseline serum albumin > 20 g/L, albumin administration had no significant effects on 28‐day mortality. Conclusion: For patients with severe sepsis due to secondary peritonitis, albumin administration may reduce 28‐day mortality in patients whose baseline serum albumin is ≤ 20 g/L, but no such effect was found in patients whose baseline serum albumin was > 20 g/L.