A prospective randomised controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum-assisted vaginal delivery

The Impact of Total Deceleration Area and Fetal Growth on Neonatal Acidemia in Vacuum Extraction Deliveries

We aimed to investigate the correlation between total deceleration area (TDA), neonatal birthweight and neonatal acidemia in vacuum extractions (VEs). This is a retrospective study in a tertiary hospital, including VE performed due to non-reassuring fetal heart rate (NRFHR). Electronic fetal monitoring during the 120 min preceding delivery was interpreted by two obstetricians who were blinded to neonatal outcomes. TDA was calculated as the sum of the area under the curve for each deceleration. Neonatal birthweights were classified as low (<2500 g), normal (2500-3999 g) or macrosomic (>4000 g). A total of 85 VEs were analyzed. Multivariable linear regression, adjusted for gestational age, nulliparity and diabetes mellitus, revealed a negative correlation between TDA in the 60 min preceding delivery and umbilical cord pH. For every 10 K increase in TDA, the cord pH decreased by 0.02 (p = 0.038; 95%CI, -0.05-0.00). The use of the Ventouse-Mityvac cup was associated with a 0.08 decrease in cord pH as compared to the Kiwi OmniCup (95%CI, -0.16-0.00; p = 0.049). Low birthweights, compared to normal birthweights, were not associated with a change in cord pH. To conclude, a significant correlation was found between TDA during the 60 min preceding delivery and cord pH in VE performed due to NRFHR.

Head position and vacuum-assisted delivery using the Kiwi Omnicup

OBJECTIVE

To evaluate the association between fetal head position during prevacuum assessment and adverse outcomes.

METHOD

This retrospective cohort study included all vacuum-assisted deliveries using the Kiwi Omnicup over 5 years. Primary outcomes were third- or fourth-degree perineal tear, pH < 7.1, and subgaleal hematoma (SGH). AGAR, neonatal intensive care unit admission, cephalohematoma, Erb's palsy, third-stage duration, and postpartum hemorrhage were secondary. Outcomes were compared between the occiput posterior (OP) and occiput anterior (OA) positions.

RESULTS

The study included 1960 patients. OP position was more likely to involve epidural analgesia (311 [82.5%] vs. 1216 [77%], P = 0.020), higher fetal head station (P = 0.001), higher percentage of cup detachments (121 cases [32.1%] vs. 307 [19.4%], P = 0.001), and longer procedure (5.5 ± 3.7 min vs. 4.7 ± 2.8 min, P = 0.001). OP was associated with umbilical cord pH < 7.1 (21 [5.5%] vs. 52 [3.9%], P = 0.032), NICU admissions (16 [4.2%] vs. 38 [2.4%], P = 0.049), SGH (18 [4.8%] vs. 38 [2.4%], P = 0.013), and high-degree perineal tears (12 [3.2%] vs. 26 [1.7%], with borderline significance, P = 0.051). SGH and high-grade tears remained significantly associated with OP position (P = 0.008 and P = 0.016, respectively) after adjusting for maternal age, nulliparity, diabetes, epidural anesthesia, preprocedure head station, and birth weight.

CONCLUSION

OP position is an independent risk-factor for anal sphincter injury and SGH during vacuum-assisted delivery.

A Rare Complication during Vaginal Delivery, Hamman's Syndrome: A Case Report and Systematic Review of Case Reports

Background: Spontaneous pneumomediastinum (SPM) during pregnancy or labor is a rare event. We presented a case report and a systematic review of the literature to provide comprehensive symptoms, treatments, and complications analysis in the pregnant population affected by SPM. Methods: We conducted a comprehensive search of four databases for published papers in all languages from the beginning to 1 September 2021; Results: We included 76 papers with a total of 80 patients. A total of 76% patients were young primiparous, with a median age of 24 ± 5.4 years. The median gestational age was 40 ± 2.4 weeks, with a median duration of labor of 7.4 ± 4.2 h. In 86%, the ethnic origin was not specified. SPM develops in 55% of cases during the second stage of labor. Subcutaneous swelling and subcutaneous emphysema were present in 91.4%. Chest pain and dyspnea were present in 51.4% and 50% of the patients, respectively. We found that 32.9% patients had crepitus, and less common symptoms were dysphonia and tachycardia (14.3% and 14.3%, respectively). Oxygen and bronchodilators were used in 37.7% of the cases. Analgesics or sedatives were administered in 27.1%. Conservative management or the observation was performed in 21.4% and 28.6%, respectively. Antibiotics treatment was offered in 14.3%, whereas invasive procedures such as chest-tube drainage were used in just 5.7% of patients. There were no complications documented in most SPM (70.0%). We found that 16.7% of the SPM developed a pneumothorax and 5% developed a pneumopericardium.; Conclusions: In pregnancy, SPM occurs as subcutaneous swelling or emphysema during the second stage of labor. The treatment is usually conservative, with oxygen and bronchodilators and a low sequela rate. A universal consensus on therapy of spontaneous pneumomediastinum in pregnancy is necessary to reduce the risk of complications.

Prospective assessment of vacuum deliveries from midpelvic station in a tertiary care university hospital: Frequency, failure rates, labor characteristics and maternal and neonatal complications

BACKGROUND

Midpelvic vacuum extractions are controversial due to reports of increased risk of maternal and perinatal morbidity and high failure rates. Prospective studies of attempted midpelvic vacuum outcomes are scarce. Our main aims were to assess frequency, failure rates, labor characteristics, maternal and neonatal complications of attempted midpelvic vacuum deliveries, and to compare labor characteristics and complications between successful and failed midpelvic vacuum deliveries.

STUDY DESIGN

Clinical data were obtained prospectively from all attempted vacuum deliveries (n = 891) over a one-year period with a total of 6903 births (overall cesarean section rate 18.2% (n = 1258). Student's t-test, Mann-Whitney U-test or Chi-square test for group differences were used as appropriate. Odds ratios and 95% confidence intervals are given as indicated. The uni- and multivariable analysis were conducted both as a complete case analysis and with a multiple imputation approach. A p-value of <0.05 was considered statistically significant.

RESULTS

Attempted vacuum extractions from midpelvic station constituted 36.7% (n = 319) of all attempted vacuum extractions (12.9% (n = 891) of all births). Of these 319 midpelvic vacuum extractions, 11.3% (n = 36) failed and final delivery mode was cesarean section in 86.1% (n = 31) and forceps in the remaining 13.9% (n = 5). Successful completion of midpelvic vacuum by 3 pulls or fewer was achieved in 67.1%. There were 3.9% third-degree and no fourth-degree perineal tears. Cup detachments were associated with a significantly increased failure rate (adjusted OR 6.13, 95% CI 2.41-15.56, p< 0.001).

CONCLUSION

In our study, attempted midpelvic vacuum deliveries had relatively low failure rate, the majority was successfully completed within three pulls and they proved safe to perform as reflected by a low rate of third-degree perineal tears. We provide data for nuanced counseling of women on vacuum extraction as a second stage delivery option in comparable obstetric management settings with relatively high vacuum delivery rates and low cesarean section rates.

Instruments for assisted vaginal birth

BACKGROUND

Assisted vaginal births are carried out to expedite birth for the benefit of mothers and babies but are sometimes associated with significant morbidity for both. Various instruments are available, broadly divided into forceps and vacuum cups, and choice may be influenced by clinical circumstances, operator preference, experience and availability.  OBJECTIVES: To evaluate the different instruments in terms of success in achieving a vaginal birth, and the risk of morbidity for mother and baby.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (14 May 2021), and reference lists of retrieved studies.

SELECTION CRITERIA

We selected randomised controlled trials of assisted vaginal birth using different instruments. The review did not include quasi-randomised trials, cluster-randomised trials or cross-over designs. The review included trials for which abstracts alone were available as long as there was sufficient information to assess eligibility.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. We used the GRADE approach to assess the certainty of evidence.  The main outcomes assessed included failed delivery with allocated instrument, any maternal trauma, third- and fourth-degree tears, postpartum haemorrhage, any neonatal trauma, low Apgar and low umbilical artery pH.  MAIN RESULTS: We included 31 studies involving a total of 5754 women.  Risk of bias criteria were largely assessed as 'unclear', due to a lack of detail in trial reports. Blinding would have been challenging for all trials due to their inability to conceal the type of instrument used from either the woman or the operator, which is reflected in the risk of bias assessment. Any type of forceps versus any type of vacuum cup (12 studies, 3129 women) Forceps may be less likely to fail in achieving vaginal birth: risk ratio (RR) 0.58, 95% confidence interval (CI) 0.39 to 0.88; 11 studies, 3080 women; low certainty. 'Any maternal trauma' may be slightly more likely with forceps: odds ratio (OR) 1.53, 95% CI 0.98 to 2.40; 5 studies, 1356 women; low certainty; and third- or fourth-degree tears may also be more likely with forceps: RR 1.83, 95% CI 1.32 to 2.55; 9 studies, 2493 women; low certainty. There is no evidence of a difference in the incidence of postpartum haemorrhage (PPH) between the two groups: RR 1.71, 95% CI 0.59 to 4.95; 2 studies, 523 women; low certainty, because the evidence is very imprecise due to a very wide CI.  More women in the forceps group reported requiring pain relief. There is probably no evidence of difference in rates of low Apgar: RR 0.83, 95% CI 0.46 to 1.51; 7 studies, 1644 women; moderate certainty; or low umbilical artery pH in the forceps group compared to any vacuum: RR 1.33, 95% CI 0.91 to 1.93; 2 studies, 789 women; low certainty; both of these outcomes are imprecise and have wide CIs that include both benefit and harm. There were also lower rates of fetal trauma with 'any forceps' (cephalhematoma, retinal haemorrhage and jaundice). The composite outcome of 'any neonatal trauma' was not reported. Low-cavity forceps versus any vacuum cup (2 studies, 218 women) We included two small studies with 218 participants in this comparison, but we judged most of the evidence as very low certainty, hence it was not feasible to make judgements on the difference in the rates of failed delivery, any maternal trauma or third- and fourth- degree tears. PPH and low umbilical artery pH were not reported. Soft vacuum cup versus any rigid cup (9 studies, 1148 women) Failed delivery may be more likely in the soft vacuum cup group: RR 1.62, 95% CI 1.21 to 2.17; 9 studies, 1148 women; low certainty. There may be no difference in the rates of 'any maternal trauma': OR 0.63, 95% CI 0.24 to 1.67; 2 studies, 348 women; low certainty, but the confidence interval is wide, indicating possible benefit or harm. There may be no difference in the rates of third- or fourth-degree tears: RR 0.93, 95% CI 0.35 to 2.44; 4 studies, 619 women; low certainty. There is probably no difference in the rates of PPH: RR 0.89, 95% CI 0.49 to 1.61; 5 studies, 737 women; moderate certainty between the soft and rigid cup groups.   There may be little or no difference in the incidence of low Apgar scores: RR 0.82, 95% CI 0.49 to 1.37; 9 studies, 1148; low certainty; or low umbilical artery pH: RR 0.80, 95% CI 0.47 to 1.36; 1 study, 100 women; low certainty. Handheld vacuum versus any vacuum cup (4 studies, 968 women) There may be no difference in the rates of failures with allocated instrument: RR 1.35, 95% CI 0.81 to 2.25; 4 studies, 962 women; low certainty, any maternal trauma: OR 1.16, 95% CI 0.71 to 1.88; 2 studies; 394 women; low certainty, PPH: RR 0.31, 95% CI 0.03 to 2.92; 1 study, 164 women; low certainty, low umbilical artery pH: RR 1.06, 95% CI 0.71 to 1.59; 1 study, 164 women; low certainty, or low Apgar scores: RR 1.25, 95% CI 0.34 to 4.61; 3 studies, 784 women; low certainty) between the two groups. There is probably no difference in the rates of third- or fourth-degree tears between the 'handheld vacuum' and 'any vacuum cup' groups: RR 1.15, 95% CI 0.62 to 2.12; 4 studies, 962 women; moderate certainty.

AUTHORS' CONCLUSIONS

This review provides low-certainty evidence that forceps may be more likely to achieve vaginal birth and have lower rates of fetal trauma, but at a greater risk of perineal trauma and higher pain relief requirements compared with vacuum cups. There was low-certainty evidence that rigid vacuum cups may be more likely to achieve a vaginal birth than soft cups but with more fetal trauma, whilst handheld vacuum cups had similar success rates compared to other cups. There was no evidence of a difference in the rates of third- or fourth-degree tears or postpartum haemorrhages between types of cups, but wide confidence intervals around the estimates indicate further research is needed in this area.

Comparison of a practice-based versus theory-based training program for conducting vacuum-assisted deliveries: a randomized-controlled trial

PURPOSE

Vacuum-assisted deliveries (VAD) are complex procedures that require training and experience to be performed proficiently. We aimed to evaluate if a more resource intensive practice-based training program for conducting VAD is more efficient compared to a purely theory-based training program, with respect to immediate training effects and persistence of skills 4-8 weeks after the initial training.

METHODS

In this randomized-controlled study conducted in maternity staff, participants performed a simulated low-cavity non-rotational vacuum delivery before (baseline test) and immediately after the training (first post-training test) as well as 4-8 weeks thereafter (second post-training test). The study's primary endpoint was to compare training effectiveness between the two study groups using a validated objective structured assessment of technical skills (OSATS) rating scale.

RESULTS

Sixty-two participants were randomized to either the theory-based group (n = 31) or the practice-based group (n = 31). Total global and specific OSATS scores, as well as distance of cup application to the flexion point improved significantly from baseline test to the first post-training test in both groups (p_all < 0.007). Skill deterioration after 4-8 weeks was only found in the theory-based group, whereas skills remained stable in the practice-based group.

CONCLUSION

A practice-based training program for conducting VAD results in comparable immediate improvement of skills compared to a theory-based training program, but the retention of skills 4-8 weeks after training is superior in a practice-based program. Future studies need to evaluate, whether VAD simulation training improves maternal and neonatal outcome after VAD.

Adverse outcomes in vacuum-assisted delivery after detachment of non-metal cup: a retrospective cohort study

PURPOSE

To evaluate neonatal and maternal outcomes associated with detachment of non-metal vacuum cup during delivery and to identify risk factors for these detachments.

METHODS

This retrospective cohort study included women with singleton pregnancy, who underwent vacuum-assisted vaginal delivery with a non-metal vacuum cup in a single academic institution, January 2014-August 2019. Failed vacuum deliveries were excluded. Primary outcomes were defined as subgaleal hematoma (SGH) and cord blood pH < 7.15. Secondary outcome included other neonatal complications and adverse maternal outcomes. Outcomes were compared between vacuum-assisted deliveries with and without cup detachment during the procedure.

RESULTS

A total of 3246 women had successful VAD and met the inclusion criteria. During the procedure, the cup detached at least once in 665 (20.5%) deliveries and did not detach in 2581 (79.5%). The cup detachment group experienced higher rates of SGH (8.9% vs. 3.5%, p = 0.001) and cord blood pH < 7.15 (9.8% vs. 7.1%, p = 0.03). There were also more neonatal intensive care unit admissions (NICU) (4.4% vs. 2.7%, p = 0.03) and more fetuses with occiput posterior position (70.8% vs. 79.4%, p = 0.001), the vacuum duration was slightly longer (6 ± 3.7 vs. 5 ± 2.9 min) and more neonates had birth weights > 3700 g (14.1% vs, 10.3%, p = 0.006). Interestingly, there were more males in that group (60.6 vs. 54.6, p = 0.005). All these factors remained significant after controlling for potential confounders.

CONCLUSIONS

Vacuum cup detachment has several predictive characteristics and is associated with adverse neonatal outcomes that should be incorporated into decisions made during the procedure.

Exploring the reporting standards of RCTs involving invasive procedures for assisted vaginal birth: A systematic review

OBJECTIVE

Assisted vaginal birth (AVB) is a complex intervention involving medical devices, comprising multiple components. This complexity creates difficulties when designing and conducting randomised controlled trials (RCTs), in terms of describing, standardising and monitoring the intervention, and accounting for differing clinician expertise. This review examines the reporting standards of complex interventions involving a medical device, in the context of AVB RCTs.

STUDY DESIGN

Searches were undertaken from the start of indexing to March 2021, and limited to RCTs, feasibility and pilot studies including at least one device for AVB. RCTs were selected if they included participants having an AVB with any device, with or without a comparator group. Reporting details were assessed according to the Consolidating Standards of Reporting Trials extension for non-pharmacological treatments (CONSORT-NPT), focusing on intervention descriptions, standardization, adherence and clinician expertise. Screening of abstracts, full-text articles and data extraction was performed by two independent reviewers.

RESULTS

Of 4098 abstracts and 83 full-text articles, 39 papers were included, investigating 80 interventions. Twenty-seven different named devices were identified. Intervention descriptions were provided in 20 (55%) papers with varying levels of detail and with only one covering the entire procedure. Standardization of interventions was mentioned in 25 papers (64%). Only eight (21%) papers reported any form of adherence to the intended procedure. Some data regarding expertise were reported in 25 (64%) papers.

CONCLUSIONS

Despite some compliance with reporting standards, there is a lack of detail regarding intervention description, standardization, adherence and expertise in RCTs of AVB. This creates difficulties in understanding how intervention delivery was intended and what actually occurred. Clearer guidelines for the reporting of invasive procedures and devices are required.

Operative vaginal delivery: all you should know

Over the last three decades, the decrease in operative vaginal delivery (OVD) has lead to an increase in the rate of cesarean sections, giving rise to intense debate amongst healthcare providers. As the use of vacuum and forceps requires personnel be adequately trained so as to become familiar with the correct use of instruments, the lack of skilled and experienced instructors may well lead to this technique being discarded in the near future. The aim of this study was to review the literature, compare the recommendations from international OVD guidelines and to illustrate the correct technique of obstetrical vacuum and forceps application to promote OVD among clinicians as a safe way of delivery.

An engineering perspective of vacuum assisted delivery devices in obstetrics: A review

Complications during childbirth result in the need for clinicians to use 'assisted delivery' in over 12% of cases (UK). After more than 50 years in clinical practice, vacuum assisted delivery (VAD) devices remain a mainstay in physically assisting child delivery; sometimes preferred over forceps due to their ease of use and reduced maternal morbidity. Despite their popularity and enduring track-record, VAD devices have shown little evidence of innovation or design change since their inception. In addition, evidence on the safety and functionality of VAD devices remains limited but does present opportunities for improvements to reduce adverse clinical outcomes. Consequently in this review we examine the literature and patent landscape surrounding VAD biomechanics, design evolution and performance from an engineering perspective, aiming to collate the limited but valuable information from a disparate field and provide a series of recommendations to inform future research into improved, safer, VAD systems.

Comparison of perinatal outcomes for all modes of second stage delivery in obstetric theatres: a retrospective observational study

OBJECTIVE

To compare rates of vaginal delivery and adverse outcomes of instrumental delivery trials in obstetric theatre compared to primary emergency full dilation caesarean section.

DESIGN

Retrospective cohort study.

SETTING

University teaching hospital.

POPULATION

Women with singleton, non-anomalous, pregnancy undergoing instrumental delivery trial in obstetric theatre.

METHODS

Data were collected from consecutive cases during 2014 until 2018 using clinical records. Multivariate regression analysis was used comparing outcomes per first delivery method.

MAIN OUTCOME MEASURES

Primary outcome was completion of vaginal delivery between all methods of instrumental delivery. Secondary outcome was a composite of immediate perinatal adverse outcomes for instrumental delivery modes and primary full dilation caesarean section.

RESULTS

From 971 deliveries analysed: ventouse delivery was significantly less likely to achieve vaginal delivery compared with Keilland's forceps delivery (odds ratio [OR] 0.42, 95% CI 0.22-0.79). Once confounding factors were adjusted for, adverse outcome rates were less frequent in the Keilland's forceps group than with primary full dilation caesarean section (OR 0.37, 95% CI 0.16-0.81); however, the receiver operating characteristic curve produced from this model demonstrated a low predictive value (AUC 0.64).

CONCLUSIONS

Attempting instrumental delivery in delivery suite theatre, as an alternative to primary emergency full dilation caesarean section, is both reasonable and safe. In this study, ventouse delivery performed poorly in comparison with other modes of instrumental delivery. Further research in the form of randomised controlled trials to identify the optimal mode of second stage delivery is paramount.

TWEETABLE ABSTRACT

Instrumental delivery trials in theatre are safe but use of ventouse was associated with a higher rate of failure.

Birth tears after spontaneous and vacuum-assisted births with different vacuum cup systems - a retrospective cohort study

Objectives Birth tears are a common complication of vaginal childbirth. We aimed to evaluate the outcomes of birth tears first by comparing the mode of vaginal birth (VB) and then comparing different vacuum cups in instrumental VBs in order to better advise childbearing women and obstetrical professionals. Methods In a retrospective cohort study, we analyzed nulliparous and multiparous women with a singleton pregnancy in vertex presentation at ≥37 + 0 gestational weeks who gave birth vaginally at our tertiary care center between 06/2012 and 12/2016. We compared the distribution of tear types in spontaneous births (SBs) vs. vacuum-assisted VBs. We then compared the tear distribution in the vacuum group when using the Kiwi Omnicup or Bird's anterior metal cup. Outcome parameters were the incidence and distribution of the different tear types dependent on the mode of delivery and type of vacuum cup. Results A total of 4549 SBs and 907 VBs were analyzed. Birth tear distribution differed significantly between the birth modes. In 15.2% of women with an SB an episiotomy was performed vs. 58.5% in women with a VB. Any kind of perineal tear was seen in 45.7% after SB and in 32.7% after VB. High-grade obstetric anal sphincter injuries (OASIS) appeared in 1.1% after SB and in 3.1% after VB. No significant changes in tear distribution were found between the two different VB modes. Conclusions There were more episiotomies, vaginal tears and OASIS after VB than after SB. In contrast, there were more low-grade perineal and labial tears after SB. No significant differences were found between different vacuum cup systems, just a slight trend toward different tear patterns.

Operative vaginal delivery: a review of four national guidelines

There is a broad range in the rates of operative vaginal deliveries (OVD) worldwide, which reflects the variety of local practice patterns, the number of trained clinicians and the lack of international evidence-based guidelines. The aim of this study was to review and compare the recommendations from published guidelines on OVD. Thus, a descriptive review of guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG), the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG), the Society of Obstetricians and Gynaecologists of Canada (SOGC) and the American College of Obstetricians and Gynecologists (ACOG) on instrumental vaginal birth was conducted. All the guidelines point out that the use of any instrument should be based on the clinical circumstances and the experience of the operator. The indications, the contraindications, the prerequisites and the classification for OVD are overall very similar in the reviewed guidelines. Further, they all agree that episiotomy should not be performed routinely. The RCOG, the RANZCOG and the SOGC describe some interventions which may promote spontaneous vaginal birth and therefore reduce the need for OVD. They also highlight the importance of adequate postnatal care and counseling. There is no consensus on the actual technique that should be used, including the type of forceps or vacuum cup, the force and duration of traction or the number of detachments allowed. Hence, there is need for international practice protocols, so as to encourage the clinicians to use OVD when indicated, minimize the complications and reduce rates of cesarean delivery.

Operative vacuum vaginal delivery: effect of compliance with recommended checklist

PURPOSE

Even if the prerequisites and the technique of vacuum extraction are largely established, the role of a checklist in this field has not been tested. To evaluate the role of a checklist implementation on the compliance with the recommended rules in operative vacuum vaginal delivery (OVD) and on maternal and perinatal outcomes.

MATERIALS AND METHODS

Retrospective cohort study on OVD between January 2012 and December 2015 at two hospitals with a tradition of teaching of OVD. A checklist for OVD was introduced in 2014. Three rules had to be recorded: fetal head station and position determination, no more than four tractions, and no more than three cup applications. Adverse maternal outcomes included third- and fourth-degree perineal tears. Adverse neonatal outcome included asphyxia, need for neonatal resuscitation, NICU admission, major head injuries, scalp injuries, and bone or brachial plexus injuries.

RESULTS

Introduction of a checklist for OVD resulted in an increase in the compliance with the rules (83.3 versus 62.8%, p < .001). Cases in which the rules were respected had lower incidence of third- and fourth-degree perineal lacerations after controlling for episiotomy, nulliparity, and indication for OVD (OR = 0.4, 95% CI 0.18-0.89), but similar rates of failure of OVD (2.1 versus 2.2%, p = 1) and adverse neonatal outcome (10.8 versus 11.7%, p=.71).

CONCLUSION

Knowledge and documented compliance with a checklist of recommended rules in OVD may assist in achieving a lower rate of severe perineal and anal sphincter injury but does not alter the success of the procedure or neonatal outcome.

Vacuum extraction for non-rotational and rotational assisted vaginal birth

Vacuum-assisted birth is a safe mode of birth in the presence of a skilled provider. Vacuum extraction can avoid prolonged second stage of labour, birth asphyxia in the presence of foetal distress or maternal pushing where contraindicated. Vacuum-assisted births - particularly those in midpelvic rotational births - have been increasingly traded for caesarean births, although the latter are generally associated with potentially a greater risk to women and (future) children. In this article, (contra)indications and the basics of vacuum technique are elaborated. A specific section is dedicated to vacuum extraction for rotational birth. If these techniques are known, trained and practiced by obstetric care givers, then vacuum extraction has tremendous potential to make childbirth safer.

Kiwi omnicup handheld versus Mityvac M-style conventional vacuum system: a retrospective observational study

INTRODUCTION

To improve the choice of vacuum-assisted delivery (VAD) system, we compared the outcomes of Kiwi handheld system and Mityvac M-style conventional system (both use disposable plastic cups).

MATERIALS AND METHODS

Retrospective observational study with data collection from electronic medical records. The study was conducted at a tertiary medical center, with approximately 7000 deliveries annually. Categorical and continuous variables were analyzed using chi-square test and t-test, respectively. p value < .05 was considered significant. The main outcomes assessed were the overall failure rate of each system, failure rates for occipito-anterior (OA) versus occipito-transverse/occipito-anterior (OT/OP) positions, +1 versus +2 fetal stations, and early maternal/neonatal outcomes.

RESULTS

During a 10-month period, there were 507 (8.4%) attempted VADs, 36 failed (7.1%), and eight (1.5%) converted to cesarean section. Of these, 364 were Kiwi-assisted and 143 Mityvac-assisted. Background characteristics were similar. The handheld system had more failures overall (9.6 versus 0.7%), at OA (7.6 versus 0.9%), and non-OA positions (17.3% versus none), at +1 (13.25 versus 0.96%) and at +2/3 stations (6.1% versus none), than the conventional system did, respectively. There was a higher rate of early post-partum hemorrhage (15.3 versus 7.4%) in the conventional group. Both systems had similar rates of third/fourth degree perineal tears, shoulder dystocia and adverse neonatal outcomes.

CONCLUSIONS

Our results suggest more failures with Kiwi compared to Mityvac, overall and at any fetal position/station, without a significant difference in adverse outcome profile.

Strategies to reduce and maintain low perinatal mortality in resource-poor settings - Findings from a four-decade observational study of birth records from a large public maternity hospital in Papua New Guinea

BACKGROUND

In many low- to middle-income countries (LMIC) assisted vaginal birth rates have fallen, while caesarean section (CS) rates have increased, with potentially deleterious consequences for maternal and perinatal mortality.

AIMS

To review birth mode and perinatal mortality in a large LMIC hospital with strict labour management protocols and expertise in vacuum extraction.

MATERIALS AND METHODS

We conducted a retrospective observational study at Port Moresby General Hospital in Papua New Guinea. Birth registers from 1977 to 2015 (39 years) were reviewed. Overall and modified (fresh stillbirths and early neonatal deaths ≥500 g) perinatal mortality rates (PMRs) were calculated by birthweight/birth mode.

RESULTS

There were 365 056 births (5215 in 1977; 14 927 in 2015), of which 14 179 (3.9%) were vacuum extractions, 609 (0.2%) forceps births and 14 747 (4.4%) CS (increase from 2% to 5%). The failure rate of vacuum extraction was 2.5% (range 0.5-5.4%). Symphysiotomy was employed for 184 births. From 1989 to 2015, the modified mean PMR for babies ≥2500 g was 8.1/1000 births (range 5.6-12.1; 6.9 in 2015), 9.1/1000 for babies ≥1500 g (7.3-14.8; 9.1 in 2015) and 7.5/1000 (0-21.7; 9.0 in 2015) for vacuum extractions (98% were ≥2500 g). The overall PMR for these years was 29.7/1000 births.

CONCLUSIONS

In an LMIC with rapidly increasing birth numbers a comparatively low PMR can be achieved while maintaining low CS rates. This may be in part accomplished through strict use of second-stage protocols, perinatal audit, and supportive training that promotes judicious and proficient use of vacuum extraction and CS.

A randomized comparison of video demonstration versus hands-on training of medical students for vacuum delivery using Objective Structured Assessment of Technical Skills (OSATS)

BACKGROUND

To compare medical students' skills for vaginal operative delivery by vacuum extraction (VE) after hands-on training versus video demonstration.

METHODS

We randomized medical students to an expert demonstration (group 1) or a hands-on (group 2) training using a standardized VE algorithm on a pelvic training model. Students were tested with a 40-item Objective Structured Assessment of Technical Skills (OSATS) scoring system after training and 4 days later. OSATS scores were the primary outcome. Performance time, self-assessment, confidence, and global rating scale were secondary outcomes. We assessed the constructive validity of OSATS in this VE model comparing metric scores of experts and students.

RESULTS

In all, 137 students were randomized. OSATS scores were higher in group 2 (n = 63) compared with group 1 (n = 74) (32.89 ± 6.39 vs 27.51 ± 10.27, respectively; P < 0.0001). Global rating scale (1.49 ± 0.76 vs 2.33 ± 0.94, respectively; P < 0.0001), confidence (2.22 ± 0.75 vs 3.26 ± 0.94, respectively; P = 0.04), self-assessment (2.03 ± 0.62 vs 2.51 ± 0.77, respectively; P < 0.0001), and performance time (38.81 ± 11.58 seconds vs 47.23 ± 17.35 seconds, respectively; P = 0.001) also favored group 2. After 4 days, this effect persisted with OSATS scores still being significantly higher in group 2 (30.00 ± 6.50 vs 25.59 ± 6.09, respectively; P = 0.001). The assessed OSATS scores showed constructive validity. In a multiple linear regression analysis, group assignment independently influenced OSATS scores, whereas sex, handedness, sports activities, and type of curriculum were not independently associated with OSATS scores.

CONCLUSIONS

Hands-on training is superior to video demonstration for teaching VE on a pelvic model.

Decreased neonatal pain response after vaginal-operative delivery with Kiwi OmniCup versus metal ventouse

BACKGROUND

Vaginal delivery, especially operative assisted vaginal delivery, seems to be a major stressor for the neonate. The objective of this study was to evaluate the stress response after metal cup versus Kiwi Omnicup® ventouse delivery.

METHODS

The study was a secondary observational analysis of data from a former prospective randomised placebo controlled multicentre study on the analgesic effect of acetaminophen in neonates after operative vaginal delivery and took place at three Swiss tertiary hospitals. Healthy pregnant women ≥35 weeks of gestation with an estimated fetal birth weight above 2000 g were recruited after admission to the labour ward. Pain reaction was analysed by pain expression score EDIN scale (Échelle Douleur Inconfort Nouveau-Né, neonatal pain and discomfort scale) directly after delivery. For measurement of the biochemical stress response, salivary cortisol as well as the Bernese Pain Scale of Newborns (BPSN) were evaluated before and after an acute pain stimulus (the standard heel prick for metabolic testing (Guthrie test)) at 48-72 h.

RESULTS

Infants born by vaginal operative delivery displayed a lower pain response after plastic cup than metal cup ventouse delivery (p < 0.001), but the pain response was generally lower than expected and they recovered fully within 72 h.

CONCLUSIONS

Neonatal pain response is slightly reduced after use of Kiwi OmniCup® versus metal cup ventouse.

TRIAL REGISTRATION

Trial was registered under under NCT00488540 on 19th June 2007.

Audit of a program to increase the use of vacuum extraction in Mulago Hospital, Uganda

BACKGROUND

Prolonged second stage of labour is a major cause of perinatal and maternal morbidity and mortality in low-income countries. Vacuum extraction is a proven effective intervention, hardly used in Africa. Many authors and organisations recommend (re)introduction of vacuum extraction, but successful implementation has not been reported. In 2012, a program to increase the use of vacuum extraction was implemented in Mulago Hospital, Uganda. The program consisted of development of a vacuum extraction guideline, supply of equipment and training of staff. The objective of this study was to investigate the impact of the program.

METHODS

Audit of a quality improvement intervention with before and after measurement of outcome parameters.

SETTING

Mulago Hospital, the national referral hospital for Uganda with approximately 33 000 deliveries per year. It is the university teaching hospital for Makerere University and most of the countries doctors and midwives are trained here. Data was collected from hospital registers and medical files for a period of two years. Main outcome measures were vacuum extraction rate, intrapartum stillbirth, neonatal death, uterine rupture, maternal death and decision to delivery interval.

RESULTS

Mode of delivery and outcome of 12 143 deliveries before and 34 894 deliveries after implementation of the program were analysed. The vacuum extraction rate increased from 0.6 - 2.4 % of deliveries (p < 0.01) and was still rising after 18 months. There was a decline in intrapartum stillbirths from 34 to 26 per 1000 births (-23.6 %, p < 0.01) and women with uterine rupture from 1.1 - 0.8 per 100 births (-25.5 %, p < 0.01). Decision to delivery interval for vacuum extraction was four hours shorter than for caesarean section.

CONCLUSIONS

A program to increase the use of vacuum extraction was successful in a high-volume university hospital in sub-Saharan Africa. The use of vacuum extraction increased. An association with improved maternal and perinatal outcome is strongly suggested. We recommend broad implementation of vacuum extraction, whereby university hospitals like Mulago Hospital can play an important role.To support implementation, we recommend further research into outcome of vacuum extraction and into vacuum extraction devices for low-income countries. Such studies are now in progress at Mulago Hospital.

Clinical impact of the disposable ventouse iCup® versus a metallic vacuum cup: a multicenter randomized controlled trial

Background

Assisted vaginal delivery by vacuum extraction is frequent. Metallic resterilizible metallic vacuum cups have been routinely used in France. In the last few years a new disposable semi-soft vacuum extraction cup, the iCup, has been introduced. Our objective was to compare maternal and new-born outcomes between this disposable cup and the commonly used Drapier-Faure metallic cup.

Methods

This was a multicenter prospective randomized controlled open clinical trial performed in the maternity units of five university hospitals and one community hospital in France from October 2009 to February 2013. We included consecutive eligible women with a singleton gestation of at least 37 weeks who required vacuum assisted delivery. Women were randomized to vacuum extraction using the iCup or usual Drapier-Faure metallic cup. The primary outcome was a composite criterion including both the risk of cup dysfunction and the most frequent maternal and neonatal harms: the use of other instruments after attempted vacuum extraction, caesarean section after attempted vacuum extraction, three detachments of the cup, caput succedaneum, cephalohaematoma, episiotomy and perineal tears.

Results

335 women were randomized to the disposable cup and 333 to extraction using the metallic cup. There was no significant difference between the two groups for the primary outcome. However, failed instrumental delivery was more frequent in the disposable cup group, mainly due to detachment: 35.6 % vs 7.1 %, p < 0.0001. Conversely, perineal tears were more frequent in the metallic cup group, especially third or fourth grade perineal tears: 1.7 % versus 5.0 %, p = 0.003. There were no significant differences between the two groups concerning post-partum haemorrhage, transfer to a neonatal intensive care unit (NICU) or serious adverse events.

Conclusions

While the disposable cup had more detachments and extraction failures than the standard metallic cup, this innovative disposable device had the advantage of fewer perineal injuries.

Trial registration

www.clinicaltrials.gov: NCT01058200 on Jan. 27 2010.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0771-1) contains supplementary material, which is available to authorized users.

Prospective cohort study of a new vacuum delivery device to assist with complicated labour in low-resource settings

OBJECTIVES

Currently available vacuum devices used to assist women undergoing complicated labour are unsuitable for use in low-resource settings. The objective of this study was to evaluate the safety and feasibility of a new low-cost vacuum device, named Koohi Goth Vacuum Delivery System (KGVDS), designed for use in low-resource settings.

METHODS

A hospital-based, multicentre, prospective cohort study with no control group was conducted in Karachi, Pakistan. After training, KGVDS devices were made available for use by labour room staff at their discretion when instrumental delivery was indicated. Women to whom KGVDS was applied were followed from the start of labour until discharge. Feasibility was assessed in terms of successful expulsion of the foetal head following application of KGVDS and ease of use ratings. Safety was assessed by observing maternal and newborn post-delivery outcomes prior to discharge.

RESULTS

Koohi Goth Vacuum Delivery System was applied to 137 women requiring instrumental delivery, of whom 111 (81%; 95% CI = 74-88%) successfully expelled the foetal head assisted by KGVDS and 103 (75%) stated that they would agree to use KGVDS again. There were no serious maternal or neonatal injuries or infections related to KGVDS use. The mean score for 'ease of use' given by doctors and midwives using the device was 8 of 10.

CONCLUSIONS

Koohi Goth Vacuum Delivery System was feasible and safe to use for assisting complicated deliveries in low-resource hospitals in this initial evaluation. Our results indicate that this new device may have the potential to improve birth outcomes in settings where most mortality occurs and that further evaluations should be conducted.

Choice of instruments for assisted vaginal delivery

BACKGROUND

Instrumental or assisted vaginal birth is commonly used to expedite birth for the benefit of either mother or baby or both. It is sometimes associated with significant complications for both mother and baby. The choice of instrument may be influenced by clinical circumstances, operator choice and availability of specific instruments.

OBJECTIVES

To evaluate different instruments in terms of achieving a vaginal birth and avoiding significant morbidity for mother and baby.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2010).

SELECTION CRITERIA

Randomised controlled trials of assisted vaginal delivery using different instruments.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality, extracted the data, and checked them for accuracy.

MAIN RESULTS

We included 32 studies (6597 women) in this review. Forceps were less likely than the ventouse to fail to achieve a vaginal birth with the allocated instrument (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.45 to 0.94). However, with forceps there was a trend to more caesarean sections, and significantly more third- or fourth-degree tears (with or without episiotomy), vaginal trauma, use of general anaesthesia, and flatus incontinence or altered continence. Facial injury was more likely with forceps (RR 5.10, 95% CI 1.12 to 23.25). Using a random-effects model because of heterogeneity between studies, there was a trend towards fewer cases of cephalhaematoma with forceps (average RR 0.64, 95% CI 0.37 to 1.11).Among different types of ventouse, the metal cup was more likely to result in a successful vaginal birth than the soft cup, with more cases of scalp injury and cephalhaematoma. The hand-held ventouse was associated with more failures than the metal ventouse, and a trend to fewer than the soft ventouse.Overall forceps or the metal cup appear to be most effective at achieving a vaginal birth, but with increased risk of maternal trauma with forceps and neonatal trauma with the metal cup.

AUTHORS' CONCLUSIONS

There is a recognised place for forceps and all types of ventouse in clinical practice. The role of operator training with any choice of instrument must be emphasised. The increasing risks of failed delivery with the chosen instrument from forceps to metal cup to hand-held to soft cup vacuum, and trade-offs between risks of maternal and neonatal trauma identified in this review need to be considered when choosing an instrument.

[Kiwi vacuum extractor versus forceps and spatula: maternal and fetal morbidity evaluation in 169 fetal extractions]

AIM

To evaluate maternal and fetal complications resulting from the use of the Kiwi vacuum extractor and to compare them with those resulting from the use of forceps or spatula.

PATIENTS AND METHODS

Patients who had instrumental extraction between November 2006 and April 2007 were included in a unicentric retrospective study. Complications resulting from the use of Kiwi vacuum extractor and those of other instruments were compared.

RESULTS

One hundred and sixty-nine patients where included, 79 had extraction with Kiwi vacuum extractor. The two populations (women having extraction with Kiwi and woman having extraction with spatula or forceps) were similar in terms of maternal characteristics, progress of labour and delivery. The rate of episiotomies was significantly lower with KIWI (73.1% versus 94.4%; P=0.0001), as well as was postpartum haemorrhage rate (8.9 % versus 18.9%; P=0.04). No perineal tear of second or third degree occurred with Kiwi. Kiwi vacuum extractor was associated with a higher rate of shoulder dystocia (12.8% versus 6.7%, NS), but related fetal complication rates were similar in the two groups. The extraction failure rate was significantly higher with Kiwi (11.4% versus 4.4%; P=0.04), but cesarean section rate was similar for the two groups (1.3 % versus 4.4%).

DISCUSSION AND CONCLUSION

This study is the first comparing complications occurring after extraction with KIWI vacuum extractor to those occurring with other instruments. Although the results are limited by the retrospective nature of the study and the small size of the workforce, our study suggests that Kiwi vacuum extractor is associated with a lower rate of maternal complications and a rate of fetal complication similar to other kind of instruments. This instrument should be promoted and taught to younger patricians. Our study also revealed higher failure and shoulder dystocia rates. Larger studies are needed to better evaluate risks factor concerning these two complications in order to optimise the use of Kiwi vacuum extractor.

[Comparative study of two single-use vacuum extractor]

OBJECTIVE

To compare the effectiveness of two single-use vacuum devices, the Kiwi Omnicup and the Mitysoft Bell.

MATERIAL AND METHODS

This retrospective study was conducted during two different periods: from January 15th to March 14th to assess the Kiwi Omnicup and from March 15th to June 15th for the Mitysoft Bell. The primary outcome was the successful completion of delivery with the allocated instrument. Secondary outcomes were fetal scalp trauma and maternal perineal lesions. All deliveries were performed by similar teams.

RESULTS

Thirty-nine patients were included in the Kiwi Omnicup group and 48 in the Mitysoft Bell group. Compared to the Kiwi Omnicup, the Mitysoft Bell was associated with a greater number of cup detachments (41.7% vs. 10.3%; p<0.01) and a significantly higher rate of failure (31.3% vs. 12.8%). Rates of substantial scalp trauma and maternal trauma were similar in both groups.

CONCLUSION

The Mitysoft Bell is not as successful at achieving a vaginal delivery as the Kiwi Omnicup. This could be explained by the shape of the cup.

New and underutilised technologies to reduce maternal mortality and morbidity: what progress have we made since Bellagio 2003?

In 2003, maternal health experts met in Bellagio, to consider new and underutilised technologies vital to pregnancy-related health services in low-resource settings. Five years later, we examine what progress has been made and what new opportunities may be on the horizon. Based on a review of literature and consultation with experts, we consider technologies addressing the five leading causes of maternal mortality: postpartum haemorrhage, eclampsia, obstructed labour, puerperal sepsis, and unsafe abortion (pregnancy termination and miscarriage). In addition, we consider technologies related to obstetric fistula, which has received more attention in recent years.

Kiwi Omnicup versus Malmstrom metal cup in vacuum assisted delivery: a randomized comparative trial

AIM

To compare the success, clinical outcomes, and maternal and neonatal complications between the Kiwi Omnicup and the Malmstrom metal cup in vacuum assisted delivery.

METHODS

This was a prospective randomized comparative trial. Women who required vacuum assisted vaginal delivery were randomized into the Kiwi Omnicup (KO) group and the Malmstrom metal cup (MM) group. The vacuum assisted deliveries were conducted according to hospital protocol. Details of the procedure and delivery outcomes including success and complications were analyzed.

RESULTS

One hundred and sixty-four women were recruited - 85 were assigned to vacuum assisted delivery using the KO and 79 the MM. One hundred percent delivery success was achieved with no significant differences between the two instruments in terms of maternal morbidity (P = 0.66). Six women in the MM group sustained post delivery complications in comparison to five in the KO group. Three babies were diagnosed with birth asphyxia in each group. More babies in the MM group were admitted to the Neonatal Intensive Care Unit (NICU) (10 babies versus 5 babies) and suffered complications (14 versus 12 babies), compared to the KO group, although the difference was not statistically significant. There were no intrapartum or neonatal deaths and of those admitted to the NICU, all were discharged within a week without any serious consequences.

CONCLUSION

Kiwi Omnicup is an effective alternative to the currently available Malmstrom metal cup for vacuum assisted delivery with no increase in maternal or neonatal morbidity or mortality.

Fetal trauma in term pregnancy

OBJECTIVE

The objective of the study was to determine the incidence and type of fetal trauma in term pregnancy in relation to method of delivery, maternal age, parity, and birthweight.

STUDY DESIGN

From the Nova Scotia Atlee Perinatal Database, fetal trauma was evaluated in all term (37 weeks or longer) singleton fetuses without major anomaly in vertex presentation over a 14-year period (1988-2001).

RESULTS

The overall risk of fetal trauma was low (2.0%); that of major fetal trauma was 0.16%. Major and minor fetal trauma was significantly increased with labor, compared with no labor (adjusted relative risks [RRs], 9.59; 95% confidence interval [CI], 1.34-68.47, and RR, 11.25; 95% CI, 5.05-25.09, respectively). Cesarean delivery was protective for major and minor fetal trauma, compared with vaginal delivery (adjusted RRs, 0.21; 95% CI, 0.12-0.40, and RR, 0.46; 95% CI, 0.39-0.54, respectively).

CONCLUSION

The risk of significant fetal trauma in term pregnancy is very low and most likely to be associated with labor and with assisted vaginal delivery.

Towards safe practice in instrumental vaginal delivery

Approximately one in ten deliveries in the Western world is an instrumental vaginal delivery. Like other surgical operations, instrumental vaginal delivery has its complications, and the operator is obliged to critically appraise the indication for the procedure and the background risk factors, and communicate effectively with the woman. Also, it calls for team work. The safe approach to instrumental delivery should therefore be similar to that adopted for other surgical operations in terms of preoperative assessment, intraoperative precautions and postoperative care. Safe practice in instrumental delivery addresses the various types of error that may occur, and places a strong premium on operator skills, competence, and familiarity with the particular instrument. This chapter reviews good practice in the conduct of instrumental delivery, highlights what could go wrong, and outlines interventions that could reduce the incidence of harm. Issues relating to communication and consent as well as training and documentation are discussed. Indications for abandonment are outlined, and the importance of situational awareness is emphasized. Safe practice tips are amply provided.

[Five questions about the Kiwi OmniCup vacuum extractor]

The vacuum extractor Kiwi OmniCup (Clinical Innovations, Muray, Utah, USA) has been developed to provide several advantages. This is a complete system with an integral hand-held vacuum operated by the obstetrician. This is also a single use instrument, which may reduce the risk of potential transmission of infections and the logistic of sterilization process. Further potential benefits of this system include the smaller overall equipment size and the ability to measure traction force. However, the data about its efficiency remain conflicting. The first works demonstrated very high successful rate of vaginal delivery, whereas two recent randomized studies showed that the Kiwi Omnicup was less efficient than currently used vacuum extractor. It appears to be as safe as conventional a device for both mother and newborn. However, further additional data remain necessary needed to complete its evaluation.

Monitoring obstetricians’ performance with statistical process control charts

OBJECTIVE

The main objective of this study was to pave the way towards proactive, continuous assessment of individuals and hospitals by demonstrating the application of evidence-based competency standards in maternity care using statistical performance monitoring.

DESIGN

Retrospective study using data routinely collected by a large maternity hospital.

SETTING

A large teaching hospital.

POPULATION

Clinicians who routinely perform either amniocentesis or ventouse deliveries.

METHOD

As a 'proof of principle', we have used statistical process control (SPC) charts to compare the observed complication rates for amniocentesis and ventouse delivery with the expected complication rates based on published data.

MAIN OUTCOME MEASURES

The recorded complication rates for amniocentesis and ventouse delivery.

RESULTS

The SPC charts identified significant variation in complication rates within the team and showed the ways in which prospective data can be used to provide continuous feedback to individuals on their performance.

CONCLUSION

The study shows that statistical performance monitoring and, in particular, the use of control charts can be a valuable tool in the continuous assessment of individuals and the healthcare service being provided. The control charts provide a more immediate indication of current performance and provide an alternative to performance-based league tables for the presentation of yearly performance data.