Automated ST-segment analysis during cesarean delivery: effects of ECG filtering modality.

STUDY OBJECTIVES: To determine the effect of different electrocardiographic (ECG) filtering modalities on ST-segment changes during cesarean delivery. We compared the use of narrow and standard bandwidth ECG filtering modes in assessing ECG-detected ischemic changes in healthy patients undergoing routine, elective cesarean delivery. DESIGN: Prospective, nonrandomized clinical trial. SETTING: Academic medical center. PATIENTS: 20 healthy parturients undergoing elective cesarean delivery with regional anesthesia. INTERVENTION: Continuous 5-lead ECG monitoring was performed in all 20 study parturients. The same incoming ECG signal was divided by a special cable and displayed on two Marquette 7010 monitors. Leads I, II, and V5 were analyzed. One of the monitors filtered the signal with a 0.07 to 100 Hz filter (DIAG), the other with a 0.3 to 40 Hz filter (MON). The ST segment was analyzed continuously by electronic comparison with a template established as a baseline at the beginning of the case. This continuous output was led in digital form every 15 seconds to an IBM PC computer for data analysis. MEASUREMENTS AND MAIN RESULTS: In each of the leads analyzed, the mean MON versus DIAG different showed a bias, with MON showing consistently lower (ie, more negative) readings than DIAG. Using different criteria for ST depression (> 0.25, > 0.5, or > 1.0mm), we categorized patients as showing more ST depression on either MON or DIAG. With the 0.25 mm criterion, ST depression was identified significantly more often in MON then DIAG in leads H and V5 (p < 0.05). Using the other criteria, the differences were similar, but were not statistically significant. In general, very few instances of ST depression were identified in lead I. No patient had sequelae indicative of intraoperative myocardial ischemia, such as chest pain, dyspnea, persistent ectopy, or hemodynamic instability. CONCLUSIONS: In patients at low risk for myocardial ischemia, narrow bandwidth (monitor mode) ECG filtering reveals greater degrees of ST-segment depression than does standard (diagnostic mode) ECG filtering. Studies examining ST-segment phenomena would be facilitated by including a description of the ECG filtering-technique.

Estimation of pharmacokinetic model parameters.

This paper addresses the problem of estimating the depth of anesthesia in clinical practice where many drugs are used in combination. The aim of the project is to use pharmacokinetically-derived data to predict episodes of light anesthesia. The weighted linear combination of anesthetic drug concentrations was computed using a stochastic pharmacokinetic model. The clinical definition of light anesthesia was based on the hemodynamic consequences of autonomic nervous system responses to surgical stimuli. A rule-based expert system was used to review anesthesia records to determine instances of light anesthesia using hemodynamic criteria. It was assumed that light anesthesia was a direct consequence of the weighted linear combination of drug concentrations in the patient's body that decreased below a certain threshold. We augmented traditional two-compartment models with a stochastic component of anesthetics' concentrations to compensate for interpatient pharmacokinetic and pharmacodynamic variability. A cohort of 532 clinical anesthesia cases was examined and parameters of two compartment pharmacokinetic models for 6 intravenously administered anesthetic drugs (fentanyl, thiopenthal, morphine, propofol, midazolam, ketamine) were estimated, as well as the parameters for 2 inhalational anesthetics (N2O and isoflurane). These parameters were then prospectively applied to 22 cases that were not used for parameter estimation, and the predictive ability of the pharmacokinetic model was determined. The goal of the study is the development of a pharmacokinetic model that will be useful in predicting light anesthesia in the clinically relevant circumstance where many drugs are used concurrently.

[Fibromas of the spermatic cord]. / I fibromi del funicolo spermatico.

The authors review the literature and report on a case of fibromatosis and a case of fibrolipoma of the spermatic cord, stressing the rarity and the therapeutic problems they may pose.

[A case of compression of the common peroneal nerve due to an intraneural mucoid pseudocyst]. / A proposito di un caso di compressione del nervo sciatico popliteo esterno da parte di una pseudocisti mucoide intraneurale.

The Authors report a case of paralysis due to compression of the external common peroneal nerve by a mucoid pseudocyst. They emphasize the rareness of such lesion, as well as the importance of a prompt diagnosis and a conservative surgical treatment.

[Angiomyolipoma of the kidney]. / L'angiomiolipoma del rene.

Kidney angiomyolipoma, although it is a benign tumour, may originate serious complications, which can endanger the patient's life. After a reviewing of the literature, the Authors show a case they had the opportunity to observe, in which it was necessary to perform the emergency nephrectomy. In the last years the modern diagnostical techniques allowed to precociously diagnose angiomyolipoma in preclinical stage, what suggests new therapeutical strategic.

[Primary torsion of the greater omentum]. / La torsione primitiva del grande omento.

Omental torsion means a partial or total rotation of omentum around its main axis, which is called primary or secondary, depending upon the presence or absence of another associated abdominal lesion. Due to the objective rareness and absence of a typical symptomatology, the diagnosis often is neither made, nor considered preoperatively. The Authors present three cases that they the opportunity to observe. They point out that, in case of laparotomy for acute painful symptomatology of the lower abdominal quadrants, one should not forget the inspection of greater omentum.

[An unusual case of a stomal complication]. / Su un caso singolare di complicanza stomale.

The Authors present a case, never reported till now, of stomal complication, and, after shortly reviewing the different colostomic complications, emphasize its rareness and hypothesize its pathogenesis.

[High-insertion choledochus]. / Il coledoco ad impianto alto.

A case of high-insertion choledochus is reported. The Authors, after a reviewing of the existing literature thereabout, describe the clinical and radiographic pictures whereby such lesion can appear. They emphasize the presence of this malformation requires particular attentions and changes in the surgical approach.