Traction force profile in children with severe perinatal outcomes delivered with a digital vacuum extraction handle: A case-control study.

INTRODUCTION: During the second stage of labor, vacuum-assisted delivery is an alternative to forceps delivery and emergency cesarean section. Extensive research concerning perinatal outcomes has indicated that the risk of complications, although rare, is higher than with a spontaneous vaginal delivery. An important factor related to perinatal outcomes is the traction force applied. Our research group previously developed a digital extraction handle, the Vacuum Intelligent Handle-3 (VIH3), that measures and records traction force. The objective of this study was to compare traction force profiles in children with and without severe perinatal outcomes delivered with the digital handle. A secondary aim was to establish a safe force limit. MATERIAL AND METHODS: This was an observational case-control study at the delivery ward at Karolinska University Hospital, Sweden. In total, 573 children delivered with the digital handle between 2012 and 2018 were included. Cases were defined as a composite of severe perinatal outcomes, including subgaleal hematoma, intracranial hemorrhage, hypoxic ischemic encephalopathy 1-3, seizures or death. The cases in the cohort were matched 1:3 based on five matching variables. Traction profiles were analyzed using the MATLAB® software and conditional logistic regression. RESULTS: The incidence of severe perinatal outcomes was 2.3%. The 13 cases were matched with three controls each (n = 39). A statistically significant increased odds for higher total traction forces was seen in the case group (odds ratio [OR] 1.004; 95% confidence interval [CI] 1.001-1.007) and for the peak force (OR 1.022; 95% CI 1.004-1.041). Several procedure-related parameters were significantly increased in the case group. As expected, some neonatal characteristics also differed significantly. An upper force limit of 343 Newton minutes (Nmin) revealed an 86% reduction in severe perinatal outcomes (adjusted OR 0.14; 95% CI 0.04-0.5). CONCLUSIONS: Children with severe perinatal outcomes had traction force profiles with significantly higher forces. The odds for severe perinatal outcomes increased for every increase in Nmin and Newton used during the extraction procedure. A calculated total force level of 343 Nmin is suggested as an upper safety limit, but this must be tested prospectively to provide validity.

Perinatal outcome after vacuum assisted delivery with digital feedback on traction force; a randomised controlled study.

BACKGROUND: Low and mid station vacuum assisted deliveries (VAD) are delicate manual procedures that entail a high degree of subjectivity from the operator and are associated with adverse neonatal outcome. Little has been done to improve the procedure, including the technical development, traction force and the possibility of objective documentation. We aimed to explore if a digital handle with instant haptic feedback on traction force would reduce the neonatal risk during low or mid station VAD. METHODS: A two centre, randomised superiority trial at Karolinska University Hospital, Sweden, 2016-2018. Cases were randomised bedside to either a conventional or a digital handle attached to a Bird metal cup (50 mm, 80 kPa). The digital handle measured applied force including an instant notification by vibration when high levels of traction force were predicted according to a predefined algorithm. Primary outcome was a composite of hypoxic ischaemic encephalopathy, intracranial haemorrhage, seizures, death and/or subgaleal hematoma. Three hundred eighty low and mid VAD in each group were estimated to decrease primary outcome from six to 2 %. RESULTS: After 2 years, an interim analyse was undertaken. Meeting the inclusion criteria, 567 vacuum extractions were randomized to the use of a digital handle (n = 296) or a conventional handle (n = 271). Primary outcome did not differ between the two groups: (2.7% digital handle vs 2.6% conventional handle). The incidence of primary outcome differed significantly between the two delivery wards (4% vs 0.9%, p < 0.05). A recalculation of power revealed that 800 cases would be needed in each group to show a decrease in primary outcome from three to 1 %. This was not feasible, and the study therefore closed. CONCLUSIONS: The incidence of primary outcome was lower than estimated and the study was underpowered. However, the difference between the two delivery wards might reflect varying degree of experience of the technical equipment. An objective documentation of the extraction procedure is an attractive alternative in respect to safety and clinical training. To demonstrate improved safety, a multicentre study is required to reach an adequate cohort. This was beyond the scope of the study. TRIAL REGISTRATION: ClinicalTrials.gov NCT03071783 , March 1, 2017, retrospectively registered.

Association of traction force and adverse neonatal outcome in vacuum-assisted vaginal delivery: A prospective cohort study.

INTRODUCTION: Traction force is a possible risk factor for adverse neonatal outcome in vacuum extraction delivery, but the knowledge is scarce and further investigation is needed. Our hypothesis was that high-level traction force increases the risk of admission to the neonatal intensive care unit. MATERIAL AND METHODS: The study was a hospital-based prospective cohort study on low- and mid-vacuum extractions at the labor and delivery ward, Karolinska University Hospital, Huddinge, Sweden. Traction forces were measured in 331 women. An electronical handle was used to measure and register traction force. The main exposure variable was high-level traction force (≥75th percentile) during the first three pulls and the primary outcome was admission to the neonatal intensive care unit. Logistic regression was used to estimate the adjusted risk. RESULTS: Among the exposed, 14/84 (16.7%) were admitted to neonatal intensive care, and among the unexposed 10/247 (4%). The crude odds ratio (OR) of admission to the neonatal intensive care unit when exposed to high-level traction force was 4.7, and the adjusted (birthweight, gestational length, cup detachment, number of pulls, duration, duration >15 minutes, mid-cavity fetal head station, failed extraction, indication and parity) OR was 2.85 (95% confidence interval [CI] 1.09-7.48). No significant effect was seen in Apgar scores <7 at 5 minutes or pH <7.1. CONCLUSIONS: High-level traction force may be a risk factor for neonatal complications. Although these results do not mandate any alterations in clinical guidelines, perioperative feedback on traction force may be useful to alert the obstetrician to a timely conversion to cesarean section. To study plausible traction force specific outcomes such as head traumas, a larger sample size is required.

Effect of team training and monitoring on the rate of failed mid and low cavity vacuum extraction: a hospital based intervention study.

BACKGROUND: Clinical team training has been advocated as a means to improve delivery care, and failed extractions is a suggested variable for clinical audit in instrumental vaginal delivery. Other activities may also have intended or unintended effects on care processes or outcomes. METHODS: We retrospectively observed 1074 mid and low vacuum extraction deliveries during three time periods (prevalence periods): Baseline (period 0), implemented team training (period 1 and 2) and monitoring of traction force during vacuum extraction (period 2). Our primary outcome was failed extraction followed by emergency cesarean section or obstetric forceps delivery. RESULTS: The prevalence proportion (relative risk) of failed extraction decreased significantly after implementation of team training, from 19% (period 0) to 8 % (period 1), corresponding to a relative risk of 0.48 [0.26-0.87]. The secondary procedural outcome complicated delivery (duration > 15 min or number of pulls > 6, or cup detachment > 1) was decreased in period 2 compared to period 1, RR 0.42 [0.23-0.76]. Secondary clinical (neonatal) outcome were not affected. CONCLUSION: Clinically based educational efforts and increased monitoring improved procedural outcome without improving neonatal outcome. The study design has inherent limitations in making causal inference.

Prophylaxis and treatment of HIV infection in pregnancy, Swedish guidelines 2024.

In May 2024, the Swedish Reference Group on Antiviral Therapy updated the guidelines on management of HIV infection in pregnancy. The most important recommendations and revisions were: (i) ART during pregnancy should be started as early as possible and continue after delivery; (ii) Suppressive ART should normally not be modified; (iii) The treatment target of HIV RNA <20 copies/ml remains; (iv) Dolutegravir/emtricitabine/tenofovir DF is the first-line drug combination also in pregnant women and women planning pregnancy; (v) There is no evidence of an increased risk of neural tube defects associated with dolutegravir; (vi) Mode of delivery for women with effective ART and HIV RNA <200 copies/ml should follow standard obstetric procedures; (vii) Caesarean section is recommended if HIV RNA ≥200 copies/ml; (viii) Scalp electrode, foetal blood sampling and/or vacuum delivery should be used on strict indications, but does not necessitate intensified infant prophylaxis; (ix) Management and mode of delivery in case of premature or full-term rupture of membranes should follow standard obstetric procedures; (x) Recommended infant antiretroviral prophylaxis has been updated; (xi) The duration of infant antiretroviral prophylaxis (gestational age ≥35 weeks and mother on effective ART and HIV RNA <200 copies/ml) has been changed from 4 to 2 weeks; (xii) Infants born to women with HIV RNA ≥200 copies/ml should receive 4 weeks of combination prophylaxis; (xiii) Fertility evaluation and assisted reproduction should be offered to women on suppressive ART according to the same principles as for other women; (xiv) Women living with HIV should still be advised against breastfeeding; (xv) Women who nevertheless opt to breastfeed should be offered intensified support and follow-up.

Predictive value of traction force measurement in vacuum extraction: Development of a multivariate prognostic model.

OBJECTIVE: To enable early prediction of strong traction force vacuum extraction. DESIGN: Observational cohort. SETTING: Karolinska University Hospital delivery ward, tertiary unit. POPULATION AND SAMPLE SIZE: Term mid and low metal cup vacuum extraction deliveries June 2012-February 2015, n = 277. METHODS: Traction forces during vacuum extraction were collected prospectively using an intelligent handle. Levels of traction force were analysed pairwise by subjective category strong versus non-strong extraction, in order to define an objective predictive value for strong extraction. STATISTICAL ANALYSIS: A logistic regression model based on the shrinkage and selection method lasso was used to identify the predictive capacity of the different traction force variables. PREDICTORS: Total (time force integral, Newton minutes) and peak traction (Newton) force in the first to third pull; difference in traction force between the second and first pull, as well as the third and first pull respectively. Accumulated traction force at the second and third pull. OUTCOME: Subjectively categorized extraction as strong versus non-strong. RESULTS: The prevalence of strong extraction was 26%. Prediction including the first and second pull: AUC 0,85 (CI 0,80-0,90); specificity 0,76; sensitivity 0,87; PPV 0,56; NPV 0,94. Prediction including the first to third pull: AUC 0,86 (CI 0,80-0,91); specificity 0,87; sensitivity 0,70; PPV 0,65; NPV 0,89. CONCLUSION: Traction force measurement during vacuum extraction can help exclude strong category extraction from the second pull. From the third pull, two-thirds of strong extractions can be predicted.