J Am Board Fam Pract: first published as 10.3122/jabfm.6.1.43 on 1 January 1993. Downloaded from Transcervical

Chris Vincent, MD, and Durlin Hickok, MD, MPH

Abslrtlet: BtIe/IgnnIful: 'l'ranscenical amnioinfusion is a new and relatively safe, simple procedure dud can be performed in most modern hospital maternity units. Metbotls: We reviewed die current medical Uterature concerning 1his topic by searching MIDLINE IDes from 1987 to die present, using key words "amnioinfusion," "fetal distress, " "prematnre ," "meconium aspiration," and "." Older articles were accessed from cross-reference of die more recent pubUcations. ResIIlts: When amnioinfusion was used to treat variable fetal heart rate deceleradons, it usually reduced die severity of the deceleradons, as well as die Cesarean section rate for fetal distress. Prophylactic transcervical amnioinfusion has been studied in 1hree other seam.: premature rupture of membranes, meconium passage during labor, and oUgohydramnios. A suggested protocol for saline amnioinfusion during labor is given. CmleIIlSlmls: Further studies are needed to confirm efficacy reports and to clarify die indications for saline amnioinfusion. 0 Am Board Fam Pract 1993; 1:43-8.)

The normal leakage of during labor cated by preterm labor and cervical incompetence seldom causes fetal problems. Variable fetal heart at 22 weeks' gestation, necessitating cervical rate (FHR) decelerations, however, can occur cerclage and treatment with indomethacin. At when the fluid volume is low enough to permit 24 weeks' gestation, a sonogram showed mild umbilical cord compression. 1 These decelera­ oligohydramnios, and indomethacin was discon­ tions, if severe and repetitive, can indicate fetal tinued. The patient was then treated with a con­ asphyxia.2 The management of severe variable tinuous infusion of subcutaneous terbutaline. A FHR decelerations includes changing maternal repeat sonogram at 32 weeks' gestation showed position, administering maternal oxygen, elevat­ normal interval fetal growth. The volume of ing the fetal presenting part, and performing vagi­ amniotic fluid was estimated to be at the lower nal or abdominal delivery.3 Recendy, transcervical limit of normal. On her admission to the hospi­ http://www.jabfm.org/ saline amnioinfusion has been used to treat vari­ tal the cerclage was removed, oxytocin augmen­ able FHR decelerations, potentially reducing the tation was begun, and she began having active Cesarean section rate for fetal distress. The pro­ contractions. cedure could be beneficial in preventing other While the patient was progressing through la­ complications of , such as premature t~nt labor, we noted variable FHR decelerations.

rupture of membranes, oligohydramnios, post­ When the patient's cervix was dilated approxi­ on 28 September 2021 by guest. Protected copyright. partum endometritis, and meconium aspiration mately 3 em, an epidural block was placed to syndrome.4,5 alleviate discomfort. A fetal scalp electrode and an intrauterine pressure catheter were placed to mustrative case monitor FHR and uterine contractions. The A 30-year-old woman, gravida 2, para 1, at 34 monitor registered one prolonged episode of fetal weeks' gestation was admitted to the hospital hav­ bradycardia (Figure lA). A second intrauterine ing had premature rupture of membranes 5 ho~ pressure catheter was placed, and amnioinfusion earlier. Her prenatal course had been compli- with normal saline was begun. The amnioinfusion reduced both the frequency and depth of variable FHR decelerations for the remainder of the first Submitted, revised, 4 March 1992. . stage of labor (Figure IB - IE). In the second From the Family Practice Clinic and the Deparanent of Pen­ stage of labor, how~r, the FHR tracing showed natal Medicine Swedish Medical Center, Seattle. Address reprint recurrent variable decelerations and terminal requests to chris Vincent, MD, Swedish Hospital Family Practice Clinic, 700 Minor Avenue, Seattle, WA 98104. bradycardia to 80 beats per minute for 5 minutes

Transcervical Amnioinfusion 43 J Am Board Fam Pract: first published as 10.3122/jabfm.6.1.43 on 1 January 1993. Downloaded from Methods We reviewed the current literature concerning this topic by using Grateful Med software to search MEDLINE files from 1987 to the present. The key words "amnio­ B infusion," "fetal distress," "pre­ mature rupture of membranes," "meconium aspiration," and "oligo­ hydramnios" were used. Older articles were accessed from cross reference of the more recent publications .

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(\ ,-, r\ Variable FUR Decelerations The first reported use of transcer- '"--.. .. _-_ .. / \----:' \._---) ''----_.. _,.' _ vical saline amnioinfusion was in D 1983.6 At that time, Miyazaki and Taylor performed saline amnioin­ fusion on 42 patients, 14 with pro­ -, longed FHR decelerations and 28 "~/"'--jt\,,--./'\~,, __ /\ ,.",!\...,_J \" __"'!?_-" ',,_, __ _ with repetitive variable FHR de­ Hi .; f2 E celerations. The FHR pattern re­ turned to normal in 12 of the 14 patients with prolonged FHR de­ celerations and 19 of the 28 with variable FHR decelerations. This study was not randomized or con­ trolled; therefore, the effect on fe­

tal outcome and Cesarean section http://www.jabfm.org/ I r ~. rate could not be determined. The authors did note, however, that the procedure was a safe, simple, and effective treatment for variable FHR decelerations. Figure 1. Ten-minute segments offetal-monitortog strip from the patient Two years later the same group on 28 September 2021 by guest. Protected copyright. presented In the text: (A) a few minutes before amnioinfusion, (8) 30 published a prospective, random­ minutes after amnioinfusion was begun, (C) 60 minutes after ized study of 96 cases of repetitive amnioinfusion was begun, (D) 90 minutes after amnioinfusion was variable FHR decelerations not begun, (£) 150 minutes after amnioinfusion was begun, (F) and at relieved by changes in maternal delivery, 230 minutes after amnioinfusion was begun. position or oxygen administra- tion.7 These patients were ran­ domly assigned to either a saline (Figure 1F). The baby was delivered by vacuum amnioinfusion group or a nontreated control extraction a few minutes later. group. Patients within each group were further At delivery, a tight nuchal cord was reduced stratified by parity. The outcome measurements without difficulty. Umbilical cord blood gases included complete relief of variable FHR decel­ were normal and infant Apgar scores were 7 at erations, Cesarean section rate for fetal distress 1 minute and 8 at 5 minutes. Both patients did and infant Apgar scores. Statistically significan~ well and had routine hospital courses. differences were noted in the Cesarean section

44 JABFP Jan.-Feb. 1993 Vol. 6 No. 1 J Am Board Fam Pract: first published as 10.3122/jabfm.6.1.43 on 1 January 1993. Downloaded from rate in the nulliparous patients who received am­ of a prospective randomized trial of saline am­ nioinfusion and in the relief of variable FHR nioinfusion in patients with PROM. Sixty-one decelerations in all patients in the infusion group. patients with fetal mean gestational age of 31 Apgar scores were similar between the study and weeks were studied. Twenty-nine women re­ control cases. ceived amnioinfusion while the remainder served More recently Owen, et al. 8 have researched as controls. Statistically significant differences the use of saline amnioinfusion in patients who were noted in the number of severe FHR decel­ either demonstrated variable FHR deceleration erations in both the first and second stages of during labor or were at risk for umbilical cord labor and in the number of mild and moderate compression resulting from the following compli­ FHR decelerations in the first stage of labor. cations: (1) post-term pregnancy, (2) preterm la­ Mean umbilical cord blood pH was also signifi­ bor with ruptured membranes, and (3) oligohy­ cantly higher in the treatment group compared dramnios. Their results showed a significantly with the control group. There were no differ­ lower rate of postpartum endometritis and a ences in the Cesarean section rates. They con­ lower, but not significantly different, Cesarean cluded that amnioinfusion for PROM was benefi­ section rate in the study patients. They concluded cial with respect to umbilical cord pH and FHR that the technique was safe and might be benefi­ decelerations. cial, but they suggested that more studies were In Japan, Ogita and others14,15 have developed warranted before they could make a general use a new transcervical catheter (pROM-fence) de­ recommendation. signed to remain in place for several days in pa­ During the last few years several researchers tients with PROM. The catheter allows infusion have attempted to pick out candidates for saline of saline or other solutions into the amniotic cav­ amnioinfusion by defining the characteristics of ity while plugging the rupture. In one study, 84 patients at risk for developing severe variable patients were treated with a continuous infusion FHR decelerations. By using the amniotic fluid of a saline solution containing a cephalosporin index, a semiquantitative sonographic assessment antibiotic. During a 6.5-day (average) course, of amniotic fluid volume, Sarno and others9 they noted a drop in the incidence of positive showed that patients with values less than 5 cm amniotic fluid cultures from 39 percent to 4 per­ were at increased risk for Cesarean section for cent. There were no apparent complications, and fetal distress, and their infants were more likely to although there was no control group for compari­ http://www.jabfm.org/ have severe variable FHR decelerations during son, they reported a 4.8 percent infection rate in labor and 1 minute Apgar scores of less than 7. the newborns compared with a reported infection IO rate in the literature of 26.5 percent in neonates Strong, et al. demonstrated that a saline am­ .. " nioinfusion of 250 mL will increase the am­ recelvmg expectant management. " niotic fluid index by an average of 4.3 em, which Wenstrom and Parsons4 conducted a prospec­ for most patients will correct the amniotic fluid tive randomized study on the prevention of loss. Chauhan observed a similar increase in the meconium aspiration syndrome by saline amnio­ on 28 September 2021 by guest. Protected copyright. in 21 patients treated with a infusion. In this study 36 out of 85 patients were 250 mL saline amnioinfusion.ll Macri, et al,12 selected to receive amnioinfusion plus routine showed a lower rate of fetal distress, higher cord care. Neonates in the study group had signifi­ blood pH, and a lower Cesarean section rate cantly better 1-minute Apgar scores and less me­ in patients in whom saline amnioinfusion was conium below the vocal cords. Mothers had sig­ used to maintain an amniotic fluid volume greater nificantly fewer operative deliveries. Sadovsky, et 16 than 10 em. al. conducted a similar randomized, controlled study of prophylactic amnioinfusion in 21 of 40 women with labor complicated by meconium. Prophylactic Use of Saline ~Ilioi~sion. . Prophylactic use of transcerncal salme amn~om- Neonates in the amnioinfusion study group had fusion has been studied in three settmgs: significantly higher cord blood pH and less me­ premature rupture of membranes (P~OM), me­ conium below the vocal cords. They were also less conium passage during labor, and oligohydram­ likely to need positive pressUre ventilation after nios. In 1985 Nageotte, et al.13 reported their results birth. There was a lower, although not signifi-

Transcervical Amnioinfusion 45 J Am Board Fam Pract: first published as 10.3122/jabfm.6.1.43 on 1 January 1993. Downloaded from cantly different, Cesarean section rate in the pressure catheter is placed and attached via an amnioinfusion group. extension tube to the transducer. A 1000-mL bag Strong, et aU studied 60 women in latent labor of 37°C 0.9 normal saline is connected to stand­ who had oligohydramnios. These patients were ard intravenous tubing fitted with an 18-gauge randomized to receive standard therapy or saline needle, which is then inserted into the side port of amnioinfusion. The study group had significantly the extention tubing (Figure 2, left). Alternatively less frequent meconium passage, fewer severe a second intrauterine catheter can be placed, and variable FHR decelerations, less frequent end­ the intravenous tubing connected directly to this stage fetal bradycardia, and fewer Cesarean sec­ catheter (Figure 2, right). tions for fetal distress. At delivery, the neonates in Initially 250 to 500 mL of fluid is infused over the study group had significantly higher cord 20 to 30 lninutes. The rate is then adjusted accord­ blood pH, but no differences in Apgar scores. In ing to the severity of the decelerations and a randomized, controlled trial of297 women with amount of vaginal fluid leakage. In the previously oligohydramnios, Schrimmer, et al. 17 also re­ mentioned studies, the infusion rate varied from ported a significantly lower rate of operative de­ 160 to 180 mLIh. Miyazaki and Nevarez7 noted liveries and higher neonatal cord blood pH in that if a single catheter is used, there will be a 35- those mothers treated prophylactically with saline to 4O-mmHg artifactual increase in the intrauter­ amnioinfusion. In a smaller randomized, con­ ine pressure reading, possibly because of resis­ trolled study of 26 women with term or post-term tance to outflow of the infusate through the cath­ complicated by oligohydramnios, eter holes. This increase in pressure does not occur prophylactic amnioinfusion significantly de­ if the infusion is run directly through a second creased the rate of severe variable FHR decelera­ catheter. A double-lumen catheter is also available tions. There were also fewer Cesarean section (lntran II, Utah Medical Products, Midvale, deliveries for fetal distress in the treatment group, Utah), eliminating the need to place two catheters. although the difference was not significant at the Although the procedure is considered safe, it is p < 0.05 level. l8 important to monitor the intrauterine pressure; respiratory failure, iatrogenic Method of Saline Amnioinfusion and elevated intrauterine pressure have been re­ A suggested protocol for saline amnioinfusion for ported. Dragich, et al. 20 described a patient with the relief of repetitive variable decelerations dur­ respiratory failure associated with amnioinfusion. ing labor has appeared in the medicalliterature.19 Tabor and Maier2 1 reported a case of polyhy­ http://www.jabfm.org/ When confronted with severe variable FHR de­ dramnios during a prolonged amnioinfusion that celerations in a laboring patient, Galvan, et al. responded to removal of amniotic fluid and recommend first performing a vaginal examina­ administration of subcutaneous terbutaline. tion to exclude a prolapsed cord. Following this Sorensen, et al. 22 also reported a case of amnio­ examination the procedure is explained to the infusion-related iatrogenic polyhydramnios that patient and consent obtained. An intrauterine responded to removal of the excess fluid. on 28 September 2021 by guest. Protected copyright.

Figure 2. Left: Single-c:atheter method of transcervical amnlolnfusion. Right: Double-catheter method of transcervical amnioinfusion. .

46 JABFP Jan.-Feb.I993 Vol. 6 No. I J Am Board Fam Pract: first published as 10.3122/jabfm.6.1.43 on 1 January 1993. Downloaded from

In a study of the effect of amnioinfusion on nioinfusion among 18 women attempting vaginal uterine pressure and activity, Posner