International journal of clinical monitoring and computing最新文献

This paper presents preliminary results of our experience, over the past three and half years, with an on-line data management system in the OR that charts and documents all features relevant to anaesthesia. We achieved two goals with this system: 1) There has been a considerable improvement in the quantity and quality of documentation, and 2) we have been able to contain costs within our department, despite an increase in workload, by the continuous audit of the quality process in our specialty. Finally we learned that the quality assurance features that we documented and later analyzed, revealed rather conflicting and disappointing results. We believe that this is at least partly due to the reluctance of our staff to accept the concept of quality assurance and quality control in our field.

We attempted to evaluate prospectively local thermoregulatory vasoconstriction and vasodilatation in 15 volunteers by means of pulse oximetry and plethysmography as measured by a finger tip-pulse oximeter. Recent studies [1] concluded that the plethysmo time interval (PTI) between the QRS complex on ECG and the upstroke of the plethysmographic wave of the pulse oximeter is useful in evaluating the peripheral circulatory status. Venous (both Vv cubitae) blood samples for determination of SvO2 were drawn, as well as pulse oximetry SpO2 oxygen saturation measurements and calculation of PTI were performed under conditions of normothermia, hypothermia and hyperthermia, before and after immersing the hands of the volunteers in a cold (15 degrees C) and warm (45 degrees C) waterbath. Two pulse oximeters simultaneously were used, one for each hand, in order to check to which extent SpO2, SvO2 and PTI might be influenced by gross limb temperature changes. Our results show that during local hyperthermia SpO2 significantly decreased and during local hypothermia SpO2 increased after immersing the one hand in a warm waterbath and the other hand in a cold waterbath at the same time. The peripheral SvO2 significantly increased in the warm hand and decreased in the cold hand. PTI remained unchanged after exposure to either a cold or a warm waterbath. The possibility of technical causes for the SpO2 changes were eliminated. Finger-tip pulse oximetry SpO2 readings change with limb temperature. The change in venous oxygen saturation can be explained by temperature dependent arteriovenous shunts in the periphery. The observed change in SpO2 probably reflects altered transmission of arterial pulsations to venous blood in the finger.

The Sophus group was founded in Denmark in 1992 with the aims of doing research into human error in anaesthesiology. Development of a simulation-environment was seen as one of the tools for research and training. This article describes the PC user interface of the SOPHUS anaesthesia simulator, SOPHUS v. 2.0 for Windows 95, and the script language, SASL v. 1.2. The script language provides possibilities of making scenarios, which develop in different directions according to the treatment of the patient by means of IF/THEN-statements, loops etc.

Introduction: Surgical patients treated in French intensive care units (ICU's) appear to have higher mortality rates than patients in the United States. We hypothesized that this may be due to the French practice of not transferring dying patients from the ICU. We wished to determine if the different mortality rates could be explained by transfer practices for dying patients or other factors such as severity of illness.

Methods: Flowsheet data for 6,787 consecutive surgical ICU (SICU) patients from our institution over a 31 month period was entered into an ICU Clinical Information System which calculated the Day 1 Simplified Acute Physiology Score (SAPS) for each patient upon admission to the SICU. SICU and overall hospital mortality data were matched with severity data and the complete data set was analyzed against results for 2,604 surgical patients in French ICU's. Since terminally ill patients in France are not transferred to floor care, we also compared the French ICU mortality rate with both our SICU mortality rate and combined SICU and surgical floor mortality rates.

Results: Our overall SICU mortality was 1.7% and our combined SICU and hospital mortality was 4.2%, while the French ICU mortality was 14.1%. The French ICU's had more patients with higher severity of illness as measured by SAPS. When the effects of ICU transfer practices and severity of illness were considered, there were no mortality differences seen among patients admitted to the different units after elective surgery. Significant differences in mortality were seen when patients admitted emergently were studied.

Conclusions: The differences in severity adjusted ICU mortality between French ICU's and our SICU are explained by different triage practices for terminally ill patients following elective ICU admission. These triage differences do not fully explain the mortality differences seen among patients emergently admitted to the ICU. Other factors such as the presence of trauma, ICU staffing practices, patient mix or other unidentified factors may be responsible for the severity adjusted differences in mortality among emergency surgical ICU patients.

We examined spectral components of beat to beat variability in AC and DC signals of the reflectance photoplethysmograph at finger and earlobe sites in 20 resting volunteers and 20 patients during propofol, alfentanil, isoflurane, nitrous oxide anaesthesia. We observed that at rest, the majority of spectral power at both sites and in both signals was in the low 'thermoregulatory' frequency band (0.01-0.08 Hz). These fluctuations were greater in the finger than in the earlobe and in the AC signal compared to the DC. With anaesthesia, low as well as mid (0.08-0.15 Hz) frequency variability decreased at both sites and in both signals whereas high frequency 'ventilatory' power (0.15-0.45 Hz) was maintained. During anaesthesia we found no significant differences between the spectral components of the AC or DC signals or between the finger and the earlobe sites. At all frequencies, the fluctuations in the AC and DC signals were out of phase with each other.

Non-invasive acoustic airway-monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an acoustic pattern of airway's geometry was then calculated. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway could be detected by its acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff.: 0.97-1) and an adequate correlation between acoustic and planimetrical determination of cross-sectional area within the tubes (corr. coeff.: 0.78). Dispersion analysis confirmed reasonable reliability of acoustic cross-sectional measurements (Coefficients of variation: 0.6-2.1%). The acoustic mapping thus provides an excellent approximation of the true displacement and/or obstruction of tracheostomy and endotracheal tubes. We conclude that acoustic monitoring may provide a helpful tool for achieving an early warning system of airway disturbancies in intubated and mechanically ventilated patients, as geometrical changes of airway configuration may be detected before they lead to relevant effects on respiratory metabolism.

This paper presents a knowledge-based decision support system to assist mechanical ventilation in patients with the Adult Respiratory Distress Syndrome (DSSARDS). The knowledge base uses clinical algorithms developed from interviews and seminars with experts. The system contains 140 rules, applies backward chaining and was built on an IBM-PC compatible microcomputer. Clinical and physiological data and ventilator settings were used for suggestions of ventilatory support mode (VSMODE) and settings (MVSET) and for hemodynamic evaluation and therapy (HEMO). Success rates (s) and kappa coefficient (k) were used to measure agreement between DSSARDS and physicians at 4 decision steps related to: beginning of mechanical ventilation (FIRSTSET), VSMODE, MVSET and HEMO, DSSARDS prototype was evaluated in a development phase with 6 patients aged 48.6 +/- 15.9 years. Agreement results for 142 decision steps were: FIRSTSET k = 0.90, s = 0.93; VSMODE k = 0.76, s = 0.92; HEMO k = 0.58, s = 0.70, MVSET k = 0.86, s = 0.92 (p < 0.05 for all k). Improvements in the knowledge base were performed mainly in HEMO and VSMODE modules. The subsequent test phase studied 5 patients aged 54.8 +/- 11.0 years in a total of 900 decision steps. Results were: FIRSTSET k = 0.93, s = 0.95; VSMODE k = 0.93, s = 0.96; HEMO k = 0.97, s = 0.99, MVSET k = 0.96, s = 0.97 (p < 0.05 for all k). The results indicate significant agreement between DSSARDS and physicians for all decision steps. This suggests that DSSARDS may be used as a support for decision making and a training tool for mechanical ventilation in patients with the adult respiratory distress syndrome.