Incidence of maternal tachycardia during the second stage of labor: a prospective observational cohort study.

OBJECTIVE: To our knowledge, this is the largest prospective study reporting on maternal heart rate (MHR) levels in laboring women (30 patients), and maternal tachycardia that is a potential risk factor in fetal monitoring confusion. Our objective was to analyze a large population of contiguous laboring patients and to assess the MHR levels attained during the second stage. METHODS: We performed a prospective study that analyzed MHR levels of second-stage laboring patients evaluating numerous predisposing maternal conditions. Univariate and stepwise multivariate logistic regression analysis were performed. RESULTS: A total of 1105 contiguous patients were analyzed and 33.9% had a sustained MHR ≥100; 18.8% had an MHR ≥110; and 9.1% had an MHR ≥120. Multivariate analysis of all potential predisposing maternal conditions did not reveal any specific variable as uniformly significant for predicting maternal tachycardia across all levels of analysis. CONCLUSIONS: The incidence of maternal tachycardia in the second stage of labor is common. We recommend that if the MHR is ≥100 during labor, the simultaneous maternal and fetal heart rate (FHR) monitoring will be used to minimize the potential for fetal monitoring confusion and risking poor fetal outcome if the fetus is in distress.

Dosimetric impact of intrafractional patient motion in pediatric brain tumor patients.

The purpose of this study was to determine the dosimetric consequences of intrafractional patient motion on the clinical target volume (CTV), spinal cord, and optic nerves for non-sedated pediatric brain tumor patients. The patients were immobilized for treatment using a customized thermoplastic full-face mask and bite-block attached to an array of reflectors. The array was optically tracked by infra-red cameras at a frequency of 10 Hz. Patients were localized based on skin/mask marks and weekly films were taken to ensure proper setup. Before each noncoplanar field was delivered, the deviation from baseline of the array was recorded. The systematic error (SE) and random error (RE) were calculated. Direct simulation of the intrafractional motion was used to quantify the dosimetric changes to the targets and critical structures. Nine patients utilizing the optical tracking system were evaluated. The patient cohort had a mean of 31 +/- 1.5 treatment fractions; motion data were acquired for a mean of 26 +/- 6.2 fractions. The mean age was 15.6 +/- 4.1 years. The SE and RE were 0.4 and 1.1 mm in the posterior-anterior, 0.5 and 1.0 mm in left-right, and 0.6 and 1.3 mm in superior-inferior directions, respectively. The dosimetric effects of the motion on the CTV were negligible; however, the dose to the critical structures was increased. Patient motion during treatment does affect the dose to critical structures, therefore, planning risk volumes are needed to properly assess the dose to normal tissues. Because the motion did not affect the dose to the CTV, the 3-mm PTV margin used is sufficient to account for intrafractional motion, given the patient is properly localized at the start of treatment.