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Biomedical subjects

Boris M Petrikovsky

Publications and source records attributed to Boris M Petrikovsky.

8 recordsLinked to original sources

Ultrasonic biophysical measurements in the normal human fetus for optimal design of the monolithic fetal pacemaker.

Ultrasound measurements, including xiphoid-to-pericardial distance and deployment angle, were made on human fetuses as a function of gestational age for the purpose of assessing the likelihood of 3 failure modes of a monolithic fetal pacemaker, including primary positioning failure due to device length and secondary dislodgement failure due to somatic growth. The small variation of the measurements over the gestational age range relevant to device implantation for the major indications of the device (for complete heart block complicated by hydrops and for bradycardia risk after fetal surgery or intrauterine intervention) predicts a small likelihood of these failure modes.

Echocardiography↗

The monolithic fetal pacemaker: prototype lead design for closed thorax deployment.

Prenatal sudden cardiac death and hydrops fetalis are often due to complete heart block. However, no pacing modality exists for intrauterine application for fetal bradycardia. A prototype lead for a novel fetal pacemaker has been developed and used in a direct pacing model. It has been demonstrated that the lead can be safely and successfully deployed using a hypochondriac and transdiaphragmatic or subxiphoid approach. Pacing with ventricular capture was evident with the widening of QRS duration from 50.2 +/- 9.8 to 95.1 +/- 12.8 ms (P = 0.0001). Further studies by echocardiogram revealed an increase in the pulse with pacing, confirming pacing. This study documents proof-of-concept for closed thorax over-the-wire deployment of a novel lead design applicable to fetal pacing. By combining the lead design with microcircuitry and a small power source, it is possible to create a monolithic fetal pacemaker system capable of being deployed in utero.

Animals↗

Viral studies on amniotic fluid from fetuses with and without abnormalities detected by prenatal sonography.

OBJECTIVE: To study the prevalence of viruses (cytomegalovirus [CMV] adenoviruses and enteroviruses) in amniotic fluid samples from fetuses with and without anomalies detected by prenatal sonography. STUDY DESIGN: Fluid samples obtained aseptically from 474 women undergoing genetic amniocentesis at our institutions from 1995 to 1996 were stored at -20 degrees C. Fetal anomalies (renal, central nervous system, gastrointestinal and cardiac) were detected by ultrasound in 162 of the fetuses. At a later date, the samples were retrieved, blinded, and tested by virus isolation techniques for CMV, adenoviruses and enteroviruses. Fisher's exact test was used for statistical analysis. RESULTS: The prevalence of viral isolation in amniotic fluid samples in fetuses with anomalies was 2.5% for CMV, 1.3% for adenovirus and 1.2% for enterovirus. Structurally normal fetuses had prevalences of 0.3%, 0% and 0%, respectively. CONCLUSION: The prevalence of viruses, especially CMV, appears to be higher in amniotic fluid from fetuses with sonographically detected anomalies.

Amniocentesis↗

Eyelid movements in normal human fetuses.

PURPOSE: We undertook this study to investigate the characteristics of blinking activity in healthy human fetuses. METHODS: Blinking activity was studied sonographically in healthy fetuses between 33 and 42 weeks' menstrual age. Horizontal and coronal sonographic views of the eye were obtained and videotaped. Fetal blinking movements were analyzed by reviewing the videotape in slow motion. Fetal vibroacoustic stimulation was also used when clinically indicated. RESULTS: We examined a total of 18 healthy fetuses. Fetal blinking was detected in 89% of cases, with a mean frequency of 6.2 movements per 60-minute observation period. Vibroacoustic stimulation was associated with increased fetal blinking in the 6 fetuses in which it was applied (mean, 15.3 movements per 60-minute observation period). CONCLUSIONS: Blinking is a normal fetal activity. The increased frequency of blinking activity associated with vibroacoustic stimulation may be considered a part of the normal startle reflex.

Acoustic Stimulation↗

"Endoview" project of intrapartum endoscopy.

INTRODUCTION: The change in obstetrical practices over the last decade in favor of trials of labor in patients with uterine scars has resulted in increased incidences of uterine ruptures. Although neither repeat cesarean delivery nor a trial of labor is risk free, evidence from a large multicenter study shows vaginal birth after the cesarean (VBAC) is associated with shorter hospital stays, fewer postpartum blood transfusions, and a decreased incidence of postpartum maternal fever. The uterine rupture remains the most serious complication associated with VBAC. Factors associated with uterine rupture include excessive exposure to oxytocin, dysfunctional labor, and a history of more than 1 cesarean delivery.2 Because uterine rupture may be a life-threatening event, intrapartum surveillance and the ability to perform an emergency surgery are both necessary when trial of labor is allowed. Until now, no early symptoms pathognomonic to uterine rupture had been described. We share our experiences with the novel approach to the problem - an intrapartum endoscopy. MATERIALS AND METHODS: Endoscopic examination was accomplished by using the intraoperational fiberscope (Olympus and Endoview system (Costa Mesa, CA, USA). A gas-sterilized 25-cm long fiberscope is introduced into the amniotic cavity through the cervical canal after rupture of the membranes. The distance between the fiberscope and the object varies from 3 to 50 mm. The fiberscope has a separate channel for the fluid infusion (normal saline) throughout the procedure; the surgeon looks through the eyepiece directly and exhibits control over the flexible scope. The duration of endoscopy is less than 15 minutes. The inserting of the endoscopic device is very similar to that of insertion of an intrauterine pressure catheter. The IRB Committees of both participating institutions approved the study protocol. Twenty-eight patients with an unknown or poorly documented site of the uterine scar were included in the study. An ultrasound examination had been performed on all patients prior to endoscopy to assess fetal wellbeing and placental location. The ages of the patients ranged from 21 to 38 years. Eighteen women had 1 previous cesarean delivery, and 10 had 2. The performance of intrapartum endoscopy did not interfere with fetal monitoring; 21 fetuses were monitored externally, 7 internally. Indications for previous cesarean deliveries were as follows: fetal distress in 11 cases, failure to progress in labor in 8, placenta previa in 2, and unknown in 7. Twenty-one patients delivered vaginally; 7 had had repeat cesarean deliveries. All neonates were born in satisfactory condition. The Apgar scores at 1 minute varied from 7 to 9 and at 5 minutes from 8 to 10. The integrity of the uterine wall was assessed by manual postpartum uterine exploration in each case of vaginal delivery and by visualization and palpation of the scar site in each abdominal delivery. RESULTS: The lower uterine segment and contractile portion of the anterior uterine wall were visualized successfully in all patients. In 25 patients, the presumed scar site looked totally indistinguishable from the rest of the lower uterine segment and anterior uterine wall. Two scars were identified as vertical in 2 patients who were delivered by a repeat abdominal operation. A vertical scar appears as a groove running in a cephalad-caudad direction from the lower uterine segment into the contractile portion of the anterior uterine wall. The usefulness of the intrapartum endoscopy is best demonstrated by the following case reports (2 of 28 study cases).

Adult↗