Effects of Immediate versus Delayed Pushing During Second-Stage Labor on Fetal Well-Being by Simpson - Article Example

Critique of Quantitative Research Article-Nursing: Simpson, Kathleen Rice; James, Dotti C. (2005). Effects of Immediate Versus Delayed Pushing During Second-Stage Labor on Fetal Well-Being: A Randomized Clinical Trial. Nursing Research, Vol. 54(3),  149–157. Introduction The quantitative research critique involves the findings of a clinical research trial (CRT) reported on a comparative assessment of two different methods of nursing care for women in second-stage labour. Second-stage labour is the most active stage of labour directly preceding delivery. As such, it is the most stressful period of labour and delivery for both mother and foetus. It has been estimated that at least 30% of neurological defects in the newborn occur during this stage of labour (ACOG & AAP, 2003; Nelson et al, 1996; Pschirrer & Yeomans, 2000). The purpose of this CRT was to monitor the effects of two alternative second stage delivery methods on foetal well-being in order to determine whether either delivery method was less stressful to foetus during labour and delivery. The first method assessed is called the immediate coached closed-glottis approach. Its use has become increasingly common over the past 15 years to assist delivery in women receiving epidural anedthesia. This method involves coached closed-glottis pushing that is initiated as soon as cervical dilation is measured at 10 cm. At this time, the woman is asked to push 3-4 times per contraction while holding her breath (closed glottis). During this interval, the knees are bought toward the abdomen and elbows are outstretched. This stimulates the Valsalva maneuver. This process continues until the baby is delivered. Despite its widespread use, there is little clinical data examining the effects of the coached closed-glottis method on the fetus during the delivery process (Mayberry et al, 2000; Thomson, 1993, 1995). The rationale for this method is that it is supposed to shorten the duration of second stage labour, thereby reducing the necessity for caesarian section while also minimizing the time that the fetus is exposed to the physiological stress of the delivery process. The alternative method is called delayed open–glottis passive method. It is often referred to as “passive descent” or labouring down”. This method is less commonly used in second stage labour than the first. It involves a less rigid approach, such that the woman is encouraged to begin pushing only when she feels the physiologic urge to push. Some clinical studies have suggested that this method is as effective as the immediate, closed-glottis coached approach; however, it may be less stressful to the fetus. This is because the passive approach does not involve maternal haemodynamic stress associated with the Valsalva maneuver which may potentially affect the fetus during delivery (Association of Women’s Health, Obstetric and neonatal Nursing, 2000; Mayberry et al, 2000; Roberts, 2002). Most of the clinical research studies to date have focused on maternal well-being associated with these alternative approaches to second stage labour. Thus, the rationale for this CRT was to address specifically the effects of these alternative methods on foetal well-being during the birthing process. Relevant Research Studies As a background for their research, the authors cited the results of numerous research studies suggesting that active second stage labour may be associated with adverse fetal effects. Among the research studies cited were the following: Research studies indicating that the delivery process exerts physiological stresses on the fetus. These include deficits in the acid-base status during second stage labour reflected in progressively lower umbilical cord blood pH with increasing labour duration times (Roemer, Harms, Buess & Harvath, 1976). A study evaluating the effects of the Valsalva maneuver demonstrated an increase in intrathoracic pressure and decreased return blood flow from the lower extremities (Caldeyro-Barcia et al, 1981). Studies recording other physiological changes including decreased maternal partial pressure of CO2 and increase pp of O2 in colrd blood delivered to the fetus during active labour (Caldeyro-Barcia et al, 1981). A study that showed the duration of active second stage labour correlated positively with increased fetal anaerobic metabolism and hypoxia which may result from increased abdominal pressure that compromises placental blood flow (Nordstrom, Achanna, Naka, & Arulkumaran, 2001). Research showing that fetal heart rate may also be accelerated by maternal pushing due to umbilical cord compression and decreased blood pH (Bassell, Humayun & Marx, 1980). Increases in fetal cerebral blood flow have also been recorded (Aldrich et al, 1995). Prior studies indicated that the coached closed-glottis approach was associated with adverse fetal effects due to increased frequency of FHR decelerations and depressed cord blood pH (Fraser et al, 2000; Hansen et al, 2002; Thomson, 1993). These transient effects produced no long-term consequence for the majority of fetus in this study. If neglected, however, there is a risk of foetal hypoxia. CRT Parameters The CRT enrolled 45 nulliparous women in second stage labour. Criteria for inclusion in the research study were general good health, >=37 weeks gestation, single foetus, elective labour induction involving the use of epidural anesthaesia. Women with complicated pregnancies or medical conditions that might affect oxygen status to the foetus such as asthma or diabetes were excluded from the study. They were randomised into two groups: Group 1 received the immediate, coached closed-glottis method; Group 2 delivery method received the delayed, open-glottis, passive approach. Foetal well-being during the delivery process was continuously monitored in both groups via foetal oxygen saturation measurements. The total amount of time that the oxygen saturation levels in the foetus were abnormal during second stage labour was recorded and compared between the two groups. Additional measurements included foetal heart rate (FHR), Apgar scores and umbilical cord gases. Maternal well-being was assessed by length of labour, perineal status and birthing method. Data were assessed by descriptive statistics and ANOVA. Group differences were analysed using ANOVA, multivariate linear regression, Mann Whitney U Test and Pearson-Chi-Square analysis. The results of this study may be summarized as follows: Fetal oxygen destauration measurements over the duration of second stage labour were significantly higher in Group 1 compared to the Group 2 (M=12.5, SD=6.4 group 1; M=4.6, SD=8.5, group 2). There was a significant difference in the number of >=2 min epochs of FSpO2 between the groups, with higher numbers recorded for Group 1. FHR variable decelerations were greater in Group 1 (M=22.4, SD=8.2) than in Group2 (M=15.6, SD=10.4). FHR prolonged decelerations were greater in group 1 (M=3.3, SD=2.8) than in Group 2 (M=1.9, SD=1.6) No significant difference3s were observed in other FHR measurements, Apgar scores or umbilical blood gases. Conclusion The results of this study suggested that the delayed, passive open-glottis breathing method was less stressful to the foetus than the immediate, closed glottis approach. This was indicated by the significant difference in fetal oxygen destauration over the duration of second stage labour as well as in a decreased number of variable and prolonged FHR decelerations in the group using the delayed method. The authors concluded that the delayed method decreases the duration of the most stressful stage of labour, the active-pushing stage, thereby decreasing the effects on foetal oxygen levels (Roberts, 2002. The authors concluded that this CRT provided strong evidence that the delayed approach is less stressful to the foetus based on the study assessment. In addition to less perturbation of oxygen levels, the delayed method also was associated with fewer recorded FHR decelerations and less maternal perineal injury. These results were cited as similar to those of other researchers who have conducted similar studies (Fraser et al, 2000; Hansen et al, 2002; Sampselle and Hines, 1999). Moreover, it should be noted that the study showed that delayed pushing did not increase the occurrence of caesarian sections nor did this method produce a negative effect on Apgar scores, indicating that the prolongation of labour associated with the delayed approach did not affect important indicators of newborn well-being. This study indicated that the benefit of reduced foetal O2 desaturation makes this delivery approach more desirable for first-time deliveries than the commonly used coached immediate method. 3 References Aldrich, C. J., DAntona, D., Spencer, J. A. D., Wyatt, J. S., Peebles, D. M., Delpy, D. T., et al. (1995). The effect of maternal pushing on cerebral oxygenation and blood volume during the second stage of labour. British Journal of Obstetrics and Gynecology, 102(6), 448–453 American College of Obstetricians and Gynecologists & American Academy of Pediatrics. (2003). Neonatal encephalopathy and cerebral palsy: Defining the pathogenesis and pathophysiology. Washington, DC: Author. Association of Womens Health, Obstetric and Neonatal Nurses. (2000). Nursing management of the second stage of labor (Evidence based clinical practice guideline). Washington, DC: Author. Bassell, G. M., Humayun, S. G., & Marx, G. F. (1980). Maternal bearing down efforts—Another fetal risk? Obstetrics and Gynecology, 56(1), 39–41. Caldeyro-Barcia, R., Giussi, G., Storch, E., Poseiro, J. J., Kettenhuber, K., & Ballejo, G. (1981). The bearing-down efforts and their effects on fetal heart rate, oxygenation, and acid base balance. Journal of Perinatal Medicine, 9(Suppl. 1), 63–67 Fraser, W. D., Marcoux, S., Krauss, I., Douglas, J., Goulet, C., & Boulvain, M., for the PEOPLE (Pushing Early or Pushing Late with Epidurals) Study Group. (2000). Multicenter randomized controlled trial of delayed pushing for nulliparous women in the second stage of labor with continuous epidural analgesia. American Journal of Obstetrics and Gynecology, 182(5), 1165–1172. Hansen, S. L., Clark, S. L., & Foster, J. C. (2002). Active pushing versus passive fetal descent in the second stage of labor: A randomized controlled trial. Obstetrics and Gynecology, 99(1), 29–34 Mayberry, L. J., Wood, S. H., Strange, L. B., Lee, L., Heisler, D. R., & Nielson- Smith, K. (2000). Second stage labor management: Promotion of evidence-based practice and a collaborative approach to patient care (Practice Monograph). Washington, DC: Association of Womens Health, Obstetric, and Neonatal Nurses. Nelson, K. B., Dambrosia, J. M., Ting, T. Y., & Grether, J. K. (1996). 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Pushing techniques in the second stage of labour. Journal of Advanced Nursing, 18(2), 171–177. Thomson, A. M. (1995). Maternal behaviour during spontaneous and directed pushing in the second stage of labour. Journal of Advanced Nursing, 22(6), 1027–1034. ; Read More