HLTH 3800 - Article Critique

HLTH 3800 - Article Critique

• 1.
  Milking Compared withDelayed Cord Clamping to Increase Placental Transfusion in Preterm Neonates Alondra DeSantiago, Amanda Francois, Elizabeth Villegas, and Karen Wortham Rabe, H., Jewison, A., Alvarez, R., Crook, D., Stilton, D., Bradley, R., & Holden, D. (2011). Milking Compared With Delayed Cord Clamping to Increase Placental Transfusion in Preterm Neonates. Obstetrics & Gynecology, 117(2), 205-211. doi:10.1097/AOG.0b013e3181fe46ff
• 2.
  Context and Rationalefor the Study Anemia due to prematurity is a significant problem seen in infants born before 33 weeks of gestation, and preterm neonates need blood transfusions in order to help with this condition. The placenta is a reservoir of fetal blood containing up to 40% of the fetal blood with as much as 15-20 mL of blood in the umbilical cord, which may be used to stabilize the infant’s circulatory system. Optimal circulating blood volume for preterm neonates has been shown to be between 75-100 mL/kg of body weight.
• 3.
  Context and Rationale(cont.) Previous studies have found that a 30 second delay in umbilical cord clamping helps with stabilization, leading to fewer transfusions needed in the neonate’s first few days of life.This is now routine practice in hospitals. Blood volume has been shown to increase by 18% by delayed clamping. Recent studies on milking techniques also show higher hemoglobin values, higher blood pressure, and less need for blood transfusions.
• 4.
  Research Hypothesis In thisstudy, researchers questioned which method would be more beneficial for preterm babies: milking the cord four times or delaying cord clamping for 30 seconds. ● Researchers hypothesized that the two methods would produce different values of hemoglobin and hematocrit. ● Exposure: milking the cord 4 times/waiting 30 seconds before clamping cord ● Health outcome: enhanced placento-fetal blood transfusion
• 5.
  Epidemiologic Study Design Thiswas a randomized, comparative trial at a single tertiary care center. The study team recruited 58 neonates over an 18-month period from 212 women who were potentially eligible participants. Preterm neonates between 24 0/7 and 32 6/7 completed weeks of gestation were included if antenatal informed consent could be obtained from the parents before delivery. Before delivery, the fetuses were randomized into two groups. 31 neonates were randomized to the clamping group and were to have the umbilical cord clamped at 30 seconds.
• 6.
  Epidemiologic Study Design(cont.) 27 neonates in the milking group would have the cord milked towards them four times at a speed of 20 cm/2 seconds. Randomization was based on computer-created tables performed by a person not involved in the trial. The randomization was stratified by gestational age, 24 0/7 to 27 6/7 completed weeks of gestation and 28 0/7 to 32 6/7 weeks of gestation. Blinding of the clinicians was not possible.
• 7.
  Results of theStudy The primary outcomes analyzed were the blood hematocrit and hemoglobin of the preterm neonates at 1 hour after birth, and these outcomes were analyzed throughout the first 6 weeks of life (or until first blood transfusion). The mean hemoglobin values for each group of preterm neonates at 1 hour after birth were 17.3 g/L for the group subjected to clamping and 17.5 g/L for the group subjected to milking (P=0.71). The only difference in mean hemoglobin values during the first 6 weeks was on day 42, where higher values were observed in the neonate group subjected to milking. There were no statistically significant differences between the groups in leukocyte or platelet counts throughout the first 6 weeks of life.
• 8.
  Results of theStudy (cont.) The two groups had similar outcomes in regard to comorbidity, mortality, and other secondary outcomes. There was no significant difference in the number of preterm neonates in each group that had to undergo blood transfusion (clamping group, 15; milking group, 17; P=0.40).
• 9.
  Issues of Interpretationfor the Study Strengths Randomization was used in this study to help control confounding and bias. The randomization helped control confounding by ensuring that individual differences between neonates did not affect the outcome. Randomization was based on computer-created tables and was conducted by an individual not involved in the study in order to eliminate some possible biased influence. In addition to computer generated randomization, the results of this randomization were kept sealed in opaque envelopes which were opened preceding delivery. This also kept experimenter bias from interfering in the randomization process.
• 10.
  Issues of Interpretationfor the Study Strengths (cont.) This study attempted to eliminate confounding variables through restriction of admission criteria. Inclusion and exclusion criteria were used. Preterm neonates were only included if antenatal informed consent of parents could be obtained. Preterm neonates were excluded if there were multiple pregnancies (twins or more), fetal hydrops, Rhesus sensitization, or other known congenital abnormalities. During analysis, confounding was also controlled through stratification of the neonates by gestational age. This allowed for the experimenters to eliminate potential confounders due to the age and maturity of the infant.
• 11.
  Issues of Interpretationfor the Study Weaknesses The inclusion of another control group of neonates randomized to immediate cord clamping would have been useful but was not ethically acceptable in a hospital where clamping the cord after 30 seconds is a standard procedure. It would have been preferable to use a more accurate measure of placental transfusion other than hemoglobin and hematocrit after birth, but other available methods are harder to perform on a large number of babies. 39 out of the 58 newborns were delivered via Cesarean section, which could have altered the results in the way that placento-fetal blood transfusion occurred different than in natural deliveries. Blinding was not possible in order to eliminate experimenter bias.
• 12.
  Author’s Conclusions This studyhas shown that, in preterm neonates, the effects from milking the cord four times are similar to the effects from waiting 30 seconds before clamping the cord. The study demonstrated that neonates allocated to milking had similar hemoglobin values after birth compared with the clamping group, indicating a similar amount of blood transfer. For future studies, researchers suggest that a more clear definition of the interventions (only one clearly stated mode of milking or time interval before clamping) will result in a better interpretation of the results and ultimately help determine the most beneficial method.
• 13.
  Group Opinion This article’sconclusions seem useful for: Healthcare professionals and expecting parents to be informed of options when it comes time for their newborn’s cord to be cut, rather than immediately after delivery. This article could be used as a conversation starter for parents to discuss and begin planning with their healthcare provider the best method of cord cutting for their baby. Understanding that milking the umbilical cord may be the better option in some scenarios when time is crucial, as this was proven to be the faster method and had comparable results to delayed clamping. Some considerations in applying the results of this study include: Only 58 neonates were studied. Perhaps increasing the number of neonates could provide health professionals with more accurate, generalizable results. Standardized procedures for each of the examined methods (milking and delayed clamping) should be created. Further research will need to be done on these two methods. The authors mention that other healthcare workers should be careful to fully document how each technique is used in future studies to be able to accurately compare the methods. There is comparatively little information known about cord milking compared to clamping, as mentioned by the study. We think that though the results from this study show consistencies with other studies done on these two methods of increasing placental transfusion, more research should be done on milking the umbilical cord before it is introduced as an alternative routine practice to 30 second delayed cord clamping. The disparity between treatment groups in the number of infants delivered via cesarean section may have biased results. Future studies should be done in order to confirm that milking and delayed clamping truly have a comparable outcome.