ﺑﺎﺯﮔﺸﺖ ﺑﻪ ﺻﻔﺤﻪ ﻗﺒﻠﯽ
خرید پکیج
تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
نسخه الکترونیک
medimedia.ir

Amnioinfusion

Amnioinfusion
Literature review current through: Sep 2023.
This topic last updated: May 18, 2023.

INTRODUCTION — Amnioinfusion refers to the instillation of fluid into the amniotic cavity. The rationale is that augmenting amniotic fluid volume may decrease or eliminate problems associated with a severe reduction or absence of amniotic fluid, such as severe variable decelerations during labor. The procedure can be performed by transcervical or transabdominal routes. Transcervical amnioinfusion for the treatment of recurrent variable decelerations is the most common indication. Other possible uses include transabdominal amnioinfusion to aid in ultrasound diagnosis or to aid external cephalic version, although supporting data are lacking.

This topic will discuss the indications, techniques, and monitoring of transcervical amnioinfusion for management of recurrent variable decelerations in labor. Information on topics related to amniotic fluid and amniocentesis are presented separately.

(See "Physiology of amniotic fluid volume regulation".)

(See "Assessment of amniotic fluid volume".)

(See "Diagnostic amniocentesis".)

In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. However, we encourage the reader to consider the specific counseling and treatment needs of transgender and gender-expansive individuals.

INDICATIONS — In general, amnioinfusion is a second-line intervention for persistent variable decelerations seen on fetal heart rate tracings during labor and appears to decrease the risk of meconium aspiration syndrome in the setting of moderate to thick amniotic-stained fluid [1,2].

(See "Intrapartum category I, II, and III fetal heart rate tracings: Management", section on 'Variable decelerations without loss of variability or accelerations'.)

(See "Meconium aspiration syndrome: Management and outcome".)

Amnioinfusion does not appear to be helpful for treatment of chorioamnionitis or oligohydramnios, or thick meconium [3,4].

(See "Oligohydramnios: Etiology, diagnosis, and management in singleton gestations", section on 'Postdiagnostic evaluation'.)

(See "External cephalic version".)

(See "Preterm prelabor rupture of membranes: Management and outcome", section on 'Amnioinfusion'.)

(See "Prelabor rupture of membranes before and at the limit of viability", section on 'Amnioinfusion'.)

(See "Clinical chorioamnionitis".)

PREPARATION

Informed consent – As with all procedures, patients undergoing amnioinfusion are consented for treatment. The main benefit is avoiding cesarean delivery in individuals with recurrent variable decelerations during labor. The main risk is that the procedure does not resolve the concerning fetal heart tracing pattern and the patient requires a cesarean delivery. Additional risks, albeit extremely rare, include umbilical cord prolapse, amniotic fluid embolism, placental abruption, chorioamnionitis, and uterine rupture [5-7]. (See 'Complications' below.)

Prophylactic antibiotics – In the absence of other indications for antibiotic use, we do not administer antibiotics during amnioinfusion. A randomized trial showed that prophylactic use of cefazolin in the infusate (1 g/1000 mL of normal saline) did not significantly reduce rates of maternal or neonatal infection [8].

MATERIALS AND EQUIPMENT — The materials and equipment are all items that are typically available on any labor and delivery unit. Required materials include:

Catheter (intrauterine pressure catheter [preferred] or pediatric nasogastric feeding tube).

Solution for infusion (Lactated Ringer solution without dextrose [preferred] or normal saline).

Method of infusion.

Tubing to connect the components. We advise using an infusion pump because it allows instillation of a known rate of fluid, but gravity drainage is possible. (See 'Transcervical approach' below.)

We prefer Lactated Ringer to normal (0.9 percent) saline because the latter may cause small changes in the concentration of fetal electrolytes [9]. However, the electrolyte concentrations remain in the physiologic range so normal saline is an acceptable alternative if Lactated Ringer solution is not available [10,11]. There is no evidence that the fluid needs to be warmed above ambient room temperature prior to administration; however, warming the fluid to body temperature is a common practice [12,13]. A blood warmer should be used rather than a blanket or surgical fluid warming oven since ovens warm fluid to a wide range of temperatures [14].

TRANSCERVICAL APPROACH — The transcervical approach is the route used for laboring patients because the fetal membranes must be ruptured for transcervical infusion. (See 'Indications' above.)

Catheter insertion — An intrauterine pressure catheter (IUPC) is inserted using standard technique described in the package materials and attached to intravenous extension tubing. While a pediatric nasogastric feeding tube can be used if an IUPC is not available, we prefer to avoid feeding tubes because intrauterine pressure monitoring cannot be performed through a feeding tube [15]. (See "Use of intrauterine pressure catheters", section on 'Technique'.)

Infusion protocol — Sterile fluid is infused through the catheter into the amniotic cavity. We use the following protocol:

Bolus amount: 250 mL to 600 mL of Lactated Ringer solution without dextrose given over 30 to 60 minutes

Continuous infusion rate: 200 mL/hr of Lactated Ringer solution without dextrose

-The continuous infusion rate is begun at the completion of the bolus above.

-Continuing the infusion may help to prevent recurrence of decelerations as some fluid will usually leak from the uterine cavity during and after the infusion.

End point: The infusion is continued until delivery is achieved, a safety concern is encountered, or it is determined that the amnioinfusion is not having the desired effect (ie, the variable decelerations do not resolve). (See 'Safety monitoring' below.)

It is important to note that infusion protocols vary across institutions and no one protocol has been proven superior. A survey of United States obstetric units revealed that they used the following methods in decreasing order of frequency: (1) a fluid bolus (50 to 1000 mL) followed by a constant infusion, (2) serial boluses (200 to 1000 mL administered every 20 minutes to four hours), and (3) constant infusion (15 to 2250 mL/hour) [5]. A randomized trial found that continuous and intermittent infusions were similarly effective [16]. Although most units use an infusion pump, this method has not been shown to result in better outcomes than gravity alone [12].

Because it is possible to introduce fluid into the uterus too rapidly, the American College of Obstetricians and Gynecologists recommends that each obstetric unit establish a protocol for intrauterine pressure monitoring during amnioinfusion or limiting the volume and rate of infusion when the technique is used [17].

Safety monitoring — We continually assess the following parameters during amnioinfusion:

Fetal heart rate should be monitored continuously to determine whether the variable decelerations resolve and to identify the occurrence of new nonreassuring fetal heart rate patterns. We stop the infusion if the intervention is not achieving a clinically desirable effect.

Assess uterine resting tone every 30 minutes to prevent excessive infusion of fluid. If the resting tone (between contractions) is noted to increase by more than 15 mmHg above the baseline, we slow or stop the infusion.

Assess fluid per vagina (color and amount) every 30 minutes. We stop the infusion if fluid becomes frankly bloody or no fluid is noted to leak out.

Assess maternal respiratory status. We stop the infusion if concerns for fluid overload arise.

If the amnioinfusion achieves the desired resolution of decelerations but the decelerations recur after the amnioinfusion is discontinued, reinitiation can be performed with the above safety monitoring.

If the amnioinfusion fails to achieve the desired resolution of decelerations in the desired amount of time, then we take other indicated measures to address the nonreassuring tracing. (See "Intrapartum category I, II, and III fetal heart rate tracings: Management".)

TRANSABDOMINAL APPROACH — Transabdominal amnioinfusion has been described for the evaluation and diagnosis of fetal anomalies in the setting of second-trimester oligohydramnios, to prolong pregnancy following midtrimester preterm premature rupture of membranes (PPROM), and to facilitate external cephalic version.

Second-trimester oligohydramnios – Although uncommon in general practice, when used, the transabdominal approach is primarily restricted to pregnancies with midtrimester oligohydramnios or anhydramnios, where it is performed to enhance ultrasound imaging or to facilitate bladder or renal pelvis shunt placement in cases of obstructive uropathies. In a retrospective descriptive study of 61 pregnancies diagnosed with severe oligohydramnios between 17 and 26 weeks of gestation, use of amnioinfusion increased the mean number of diagnosed ultrasound findings from 0.39 (±0.45) to 1.59 (±1.24) [18]. The most frequently diagnosed abnormalities were renal (59 percent), previously undiagnosed PPROM (21 percent), and fetal growth restriction (18 percent).

Of note, although there are case reports, case series, and retrospective reviews of using serial amnioinfusion in pregnancies complicated by oligohydramnios, repeated amnioinfusion is not an established management strategy for these individuals [19-22]. Serial amnioinfusion in the setting of midtrimester PPROM is controversial. An ongoing multicenter randomly-assigned trial is comparing the use of serial amnioinfusion with expectant management following midtrimester PPROM [23]. (See "Prelabor rupture of membranes before and at the limit of viability", section on 'Amnioinfusion'.)

The transabdominal procedure does not differ from amniocentesis, except fluid is instilled rather than removed. Room temperature Lactated Ringer solution is manually infused until the desired level of ultrasound visualization is achieved. The infused volume is generally less than 100 mL. (See "Diagnostic amniocentesis".)

Third-trimester external cephalic version – While transabdominal amnioinfusion has been proposed to aid external cephalic version (ECV) of breech or transverse fetuses at term, supporting data are sparse, and thus we do not advise using amnioinfusion for this indication. A 2015 systematic review of trials and quasi-randomized trials reported that the body of evidence was insufficient to permit conclusions regarding efficacy and safety [24]. A subsequent trial reported no differences in the rates of cephalic presentation at delivery for 119 self-reported women at term with a breech fetus and one prior unsuccessful ECV attempt that were randomly assigned to amnioinfusion or no infusion prior to repeat ECV with a senior obstetrician (20 versus 12 percent) [25].

COMPLICATIONS — Complications of transcervical amnioinfusion are rare. While maternal amniotic fluid embolism has been described in case reports, a clear relationship to the procedure has not been documented [7,26]. Similarly, there does not appear to be any additional risk of cord prolapse [27] or uterine rupture in self-reported women with previous cesarean delivery [28]. Transcervical amnioinfusion may increase the risk of chorioamnionitis by washing out the amniotic fluid, which has bacteriostatic properties, or by the introduction of a foreign body to a region colonized by bacteria. In a meta-analysis that included one trial of 116 self-reported women, amnioinfusion was associated with increased risk of postpartum fever, but not with postpartum endometritis [29]. However, it is impossible to exclude the possibility of a small increase in risk given the small number of reported complications.

Iatrogenic complications have also been rarely reported. Iatrogenic polyhydramnios has been described and was associated with elevated intrauterine pressure and fetal bradycardia [30]. A case report attributed excessive fluid infusion and intrauterine manipulation to development of a shoulder presentation in a previously vertex presenting fetus [31]. In addition, there is potential risk for placental injury or disruption by the intrauterine pressure catheter, particularly at the time of placement.

Data regarding complications of transabdominal amnioinfusion are sparse because this technique is not routine and because it is typically employed in pregnancies that have additional complications, such as oligohydramnios or preterm premature rupture of the membranes (PPROM). One trial of 58 self-reported women reported no differences in maternal or fetal outcomes among those assigned to receive serial amnioinfusion for very early PPROM compared with expectant management.

SUMMARY AND RECOMMENDATIONS

Procedure and indications – Amnioinfusion, or the instillation of fluid into the amniotic cavity, is a second-line intervention for persistent variable decelerations seen on fetal heart rate tracings during labor. As with all procedures, patients undergoing amnioinfusion are consented for treatment. Antibiotic prophylaxis is not indicated. (See 'Indications' above and 'Preparation' above.)

Materials and equipment – The materials and equipment are those commonly found on labor and delivery units and include a catheter, solution, infusion pump, and connecting tubing. We prefer Lactated Ringer to normal (0.9 percent) saline because the latter may cause small changes in the concentration of fetal electrolytes. However, the electrolyte concentrations remain in the physiologic range so normal saline is an acceptable alternative if Lactated Ringer solution is not available. (See 'Materials and equipment' above.)

Transcervical infusion during labor – The transcervical approach is the route used for laboring patients; the fetal membranes must be ruptured for transcervical infusion.

Protocols – Protocols for amnioinfusion vary across institutions. There is no evidence that any one method is superior in terms of safety, efficacy, or complications rates. (See 'Transcervical approach' above.)

Monitoring – During transcervical amnioinfusion, we routinely monitor the infusion rate, fetal heart rate, fluid per vagina, and maternal respiratory status. (See 'Safety monitoring' above.)

Transabdominal infusion – Transabdominal amnioinfusion has been described for the evaluation and diagnosis of fetal anomalies in the setting of second trimester oligohydramnios and to facilitate external cephalic version. However these are not standard indications and supporting data are sparse. (See 'Transabdominal approach' above.)

Risks and complications – The main risk of amnioinfusion is that it may not resolve a concerning fetal heart rate tracing. Rare complications have been reported including amniotic fluid embolism, cord prolapse, and uterine rupture, although it is not clear if the amnioinfusion was the cause. (See 'Complications' above.)

ACKNOWLEDGMENTS — The editorial staff at UpToDate acknowledge Henry Roque, MD, MS, Jonathan Gillen-Goldstein, MD, and Edmund Funai, MD, who contributed to an earlier version of this topic review.

  1. Hofmeyr GJ, Lawrie TA. Amnioinfusion for potential or suspected umbilical cord compression in labour. Cochrane Database Syst Rev 2012; 1:CD000013.
  2. Davis JD, Sanchez-Ramos L, McKinney JA, et al. Intrapartum amnioinfusion reduces meconium aspiration syndrome and improves neonatal outcomes in patients with meconium-stained fluid: a systematic review and meta-analysis. Am J Obstet Gynecol 2023; 228:S1179.
  3. Hofmeyr GJ, Kiiza JA. Amnioinfusion for chorioamnionitis. Cochrane Database Syst Rev 2016; :CD011622.
  4. Novikova N, Hofmeyr GJ, Essilfie-Appiah G. Prophylactic versus therapeutic amnioinfusion for oligohydramnios in labour. Cochrane Database Syst Rev 2012; :CD000176.
  5. Wenstrom K, Andrews WW, Maher JE. Amnioinfusion survey: prevalence, protocols, and complications. Obstet Gynecol 1995; 86:572.
  6. Dragich DA, Ross AF, Chestnut DH, Wenstrom K. Respiratory failure associated with amnioinfusion during labor. Anesth Analg 1991; 72:549.
  7. Maher JE, Wenstrom KD, Hauth JC, Meis PJ. Amniotic fluid embolism after saline amnioinfusion: two cases and review of the literature. Obstet Gynecol 1994; 83:851.
  8. Edwards RK, Duff P. Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid. Infect Dis Obstet Gynecol 1999; 7:153.
  9. Shields LE, Moore TR, Brace RA. Fetal electrolyte and acid-base responses to amnioinfusion: lactated Ringer's versus normal saline in the ovine fetus. J Soc Gynecol Investig 1995; 2:602.
  10. Gonzalez JL, Mooney S, Gardner MO, et al. The effects of amnioinfused solutions for meconium-stained amniotic fluid on neonatal plasma electrolyte concentrations and pH. J Perinatol 2002; 22:279.
  11. Puder KS, Sorokin Y, Bottoms SF, et al. Amnioinfusion: does the choice of solution adversely affect neonatal electrolyte balance? Obstet Gynecol 1994; 84:956.
  12. Glantz JC, Letteney DL. Pumps and warmers during amnioinfusion: is either necessary? Obstet Gynecol 1996; 87:150.
  13. Nageotte MP, Bertucci L, Towers CV, et al. Prophylactic amnioinfusion in pregnancies complicated by oligohydramnios: a prospective study. Obstet Gynecol 1991; 77:677.
  14. Burrows WR, Gervasi L, Kosty D, et al. Warming fluid for amnioinfusion during labor. J Reprod Med 1995; 40:123.
  15. Abdel-Aleem H, Amin AF, Shokry M, Radwan RA. Therapeutic amnioinfusion for intrapartum fetal distress using a pediatric feeding tube. Int J Gynaecol Obstet 2005; 90:94.
  16. Rinehart BK, Terrone DA, Barrow JH, et al. Randomized trial of intermittent or continuous amnioinfusion for variable decelerations. Obstet Gynecol 2000; 96:571.
  17. Guidelines for Perinatal Care, 8th edition, American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (Ed), Elk Grove Village, IL and Washington D.C. 2017.
  18. Vikraman SK, Chandra V, Balakrishnan B, et al. Impact of antepartum diagnostic amnioinfusion on targeted ultrasound imaging of pregnancies presenting with severe oligo- and anhydramnios: An analysis of 61 cases. Eur J Obstet Gynecol Reprod Biol 2017; 212:96.
  19. Haeri S, Simon DH, Pillutla K. Serial amnioinfusions for fetal pulmonary palliation in fetuses with renal failure. J Matern Fetal Neonatal Med 2017; 30:174.
  20. Morita A, Kondoh E, Kawasaki K, et al. Therapeutic amnioinfusion for chronic abruption-oligohydramnios sequence: a possible prevention of the infant respiratory disease. J Obstet Gynaecol Res 2014; 40:1118.
  21. Takahashi Y, Iwagaki S, Chiaki R, et al. Amnioinfusion before 26 weeks' gestation for severe fetal growth restriction with oligohydramnios: preliminary pilot study. J Obstet Gynaecol Res 2014; 40:677.
  22. Esaki M, Maseki Y, Tezuka A, Furuhashi M. Continuous amnioinfusion in women with PPROM at periviable gestational ages. J Matern Fetal Neonatal Med 2020; 33:1151.
  23. van Teeffelen AS, van der Ham DP, Willekes C, et al. Midtrimester preterm prelabour rupture of membranes (PPROM): expectant management or amnioinfusion for improving perinatal outcomes (PPROMEXIL - III trial). BMC Pregnancy Childbirth 2014; 14:128.
  24. Cluver C, Gyte GM, Sinclair M, et al. Interventions for helping to turn term breech babies to head first presentation when using external cephalic version. Cochrane Database Syst Rev 2015; :CD000184.
  25. Diguisto C, Winer N, Descriaud C, et al. Amnioinfusion for women with a singleton breech presentation and a previous failed external cephalic version: a randomized controlled trial. J Matern Fetal Neonatal Med 2018; 31:993.
  26. Dorairajan G, Soundararaghavan S. Maternal death after intrapartum saline amnioinfusion--report of two cases. BJOG 2005; 112:1331.
  27. Roberts WE, Martin RW, Roach HH, et al. Are obstetric interventions such as cervical ripening, induction of labor, amnioinfusion, or amniotomy associated with umbilical cord prolapse? Am J Obstet Gynecol 1997; 176:1181.
  28. Hicks P. Systematic review of the risk of uterine rupture with the use of amnioinfusion after previous cesarean delivery. South Med J 2005; 98:458.
  29. Pierce J, Gaudier FL, Sanchez-Ramos L. Intrapartum amnioinfusion for meconium-stained fluid: meta-analysis of prospective clinical trials. Obstet Gynecol 2000; 95:1051.
  30. Tabor BL, Maier JA. Polyhydramnios and elevated intrauterine pressure during amnioinfusion. Am J Obstet Gynecol 1987; 156:130.
  31. Washburne JF, Chauhan SP, Magann EF, et al. Amnioinfusion-induced malpresentation. J Miss State Med Assoc 1998; 39:240.
Topic 5383 Version 26.0

References

آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟