How To Test For Fetal Blood

Transcription

1 Fetal (FBS) / paired cord blood sampling guideline (GL839) Approval Approval Group Job Title, Chair of Committee Date Maternity & Children s Services Clinical Governance Committee Mr Mark Selinger, Consultant Obstetrician 2 nd May 2014 Change History Version Date Author, job title Reason 1.0 M Selinger, J Siddall Trust requirement (Consultants in Feto maternal medicine) 2.0 M Selinger, J Siddall Review due 3.0 M Selinger, J Siddall Review due 4.0 M Selinger, J Siddall Review due 5.0 M Selinger, J Siddall Review due 6.0 March 2012 M Selinger, J Siddall, P Street Changes in red 7.0 March 2014 M Selinger, J Siddall (Consultants in Feto maternal medicine) Review due If necessary, please also refer to the following guidelines: Cardiotography intrapartum guideline (V7.1 Feb 14) Cardiotograpy intrapartum gline V7. 1 Author: M Selinger, J Siddall March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 1 of 8

2 Overview: Fetal heart rate pattern analysis is a screening test for acidosis in labour; FBS is the gold standard diagnostic test. Paired cord blood gas analysis provides the only practical objective measure of the infant's condition at birth. In women with a low risk labour, if an abnormality in fetal heart rate is suspected, the mother should be advised that she should be transferred to a setting where continuous electronic monitoring can be deployed and fetal blood sampling performed if the abnormality is confirmed as described below 1,2. Indications: the CTG exhibits one abnormal (such as a prolonged bradycardia, but with recovery), or two or more, suspicious features, such as persistent variable decelerations, a low baseline (less than 110bpm) or a high baseline (greater than 160 bpm), reduced baseline variability less than 5 for more than forty minutes (see Cardiotography; intrapartum guideline). Contraindications: Where there is clear evidence of acute fetal compromise (for example, prolonged deceleration greater than 3 minutes with no sign of recovery), FBS should not be undertaken and urgent preparations to expedite birth should be made. Mother known to have HIV or Hepatitis B or C, active Herpes simplex Maternal pyrexia above C Fetal bleeding disorder (known or suspected from family history) <34 weeks gestation Face presentation Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 2 of 8

3 Procedure: Explanation to patient Set up trolley with FBS pack, good light source and other equipment as required Midwife in attendance Mother placed in left or right lateral position, good light, assistant, equipment Amnioscope passed up vagina to rest on fetal scalp. Sufficient contact on scalp to exclude amniotic fluid contamination Clean fetal scalp with swab from FBS pack Spray with ethyl chloride Smear skin with silicone jelly Stab scalp with guarded blade (do not twist, slice or carve with blade) Droplet of blood collected by capillary action into heparinised tube (no bubbles) On capillary samples insert a flea immediately the sample has been taken and agitate with the magnet to disperse heparin into the sample to prevent clots forming Blood gas analysis immediately Apply gentle pressure on the incision with a swab to secure haemostasis. In the event of the blood gas analyser on delivery suite being out of action samples can be processed on Buscot. N.B. The registrar on call should be informed if vaginal bleeding is noted or started after FBS. In case of new onset vaginal bleeding after FBS, bleeding from the fetal scalp should be excluded by direct vision of the fetal scalp with an amnioscope 3. Interpretation: FBS result ph Interpretation Action 7.25 Normal Repeat FBS within an hour if CTG pathological or it does not improve. Consider sooner if CTG deteriorates Borderline Repeat FBS within 30 minutes if CTG pathological. Consider sooner if added risk factor i.e. IUGR present or CTG deteriorates 7.20 Abnormal Expedite delivery Discuss case with Consultant on call Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 3 of 8

4 These results should be interpreted taking into account any previous ph measurement, the rate of progress in labour and the clinical features of the woman and baby. The obstetrician should document a plan of action in the maternal records detailing when the case will be reviewed, which may include the interval to the time when a second sample should be obtained. If the FHR trace pattern remains unchanged and the FBS result is stable after a second test, further sampling may be deferred unless additional abnormalities develop on the CTG trace. Where a third FBS is considered necessary, a consultant obstetric opinion should be sought. If FBS is not feasible or there are no FBS results the case must be discussed with the Consultant on call. Paired cord samples 4 Paired samples means that here are both arterial and venous samples taken from the cord. There are two arteries and one vein (AVA), the arteries carrying deoxygenated blood (blue in the diagram) and the vein the oxygenated blood (red in diagram below). It is easier to obtain the venous sample first as this is the largest vessel in the cord, then the arterial one. At delivery paired cord samples should be obtained from: All babies who had FBS in labour All instrumental vaginal deliveries All emergency caesarean sections All vaginal breech deliveries All babies born in poor condition i.e. apgar scores of less than 5 at 1 minute and less than 7 at 5 minutes. 5 Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 4 of 8

5 All babies of diabetic mothers, i.e. insulin, metformin and diet controlled All cases of shoulder dystocia All cases with intrapartum fever >38 All multiple pregnancies All babies of mothers with thyroid disease All babies with intrapartum pathological CTG trace. All babies with severe growth restriction All preterm babies greater than 24 weeks. All babies with thick meconium during labour. Heparinised syringes should be used to take the sample as soon as practical possible from the cord vessels. Blood can be collected from a clamped cord up to 60 minutes after delivery. The sample should be rolled in the syringe as soon as taken from the cord to disperse heparin from the syringe. This needs to be done immediately and not after both the cord samples have been taken otherwise the samples will start to clot. The syringes should be identified as venous or arterial. The sample should be analysed as soon as practical and within an hour of collection 6,7. If there is difficulty in obtaining blood from the umbilical artery, blood can be obtained from an artery on the fetal surface of the placenta. These arteries can be recognised because they cross over the veins. It is advisable to sample the cord close to the cut end. After the sampling reposition the artery clamps nearer to the placenta and above the puncture sites. Thus leaking of blood from the puncture sites is prevented and blood in the cord is preserved in case repeat sampling is indicated. The cord must remain double clamped until reliable and accurate results are available. To check whether the results are reliable, please use the algorithm in appendix 1 Write all blood gas results in the maternity notes preferably on the reverse of partogram in the tables printed. Store the printed results in the brown intrapartum envelope Inform paediatrician if cord arterial ph values <ph 7.05 or base excess of -12 Ensure that Apgar scores are written on the neonatal record. Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 5 of 8

6 References: 1. Royal College of Obstetricians & Gynaecologists (2001) Evidence-based clinical guidance No 8: The use of electronic fetal monitoring. 2. National Institute for Health & Clinical Excellence (2007). Intrapartum care: care of healthy women and their babies during childbirth. London. NICE 3. Westgate J, Garibaldi JM, Greene KR. Umbilical cord blood gas analysis at delivery: a time for quality data. Br J Obstet Gynaecol1994;101: Sabir, Hemmen; Stannigel, Hans; Schwarz, Annika; Hoehn, Thomas. Perinatal haemorrhagic shock following fetal scalp blood sampling. Obstetrics & Gynaecology. 115(2, Part 2): Duerbeck NB, Chaffin DG, Seeds JW. A practical approach to umbilical artery ph and blood gas determination. Obstet Gynaecol 1992;79: ACOG Committee Opinion No. 348, November 2006: Umbilical cord blood gas and acid-base analysis. Obstet Gynaecol 2006;108: (*Amendments made 24/1/12 at P Street request ) 6. Riley RJ, Johnson JW. Collecting and analyzing cord blood gases. Clin Obstet Gynaecol 1993;36: Armstrong L, Stenson B. Effect of delayed sampling on umbilical cord arterial and venous lactate and blood gases in clamped and unclamped vessels. Arch Dis Child Fetal Neonatal Ed 2006;91:F342 5 Auditable standards: 1. The indication for a first FBS and the requirement and timing of repeated FBS will be followed as stated in the guideline. All FBS results will be documented on the reverse of the partogram or intrapartum care record. 2. The consultant obstetrician will be informed in all cases when a third FBS is considered necessary. 3. Paired cord samples will be taken in the following circumstances: previous FBS in labour, assisted vaginal delivery, emergency caesarean delivery, breech delivery, babies born in poor condition (apgars less than 7 at 5 minute), diabetic mothers and shoulder dystocia. All paired cord blood samples will be documented on one of the following the reverse of the partogram, the elective caesarean section pathway, emergency procedure pathway or intrapartum record. 4. Both FBS and paired cord blood sample printout results will be stored in the brown intrapartum CTG envelope securely attached to the maternal health record. Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 6 of 8

7 Appendix 1 UMBILICAL CORD BLOOD GAS ANALYSIS Is the blood analyser working? Results available Take sample to Buscot or ITU Call the clinical engineer (even out of hours). Check ph Is arterial ph lower than venous ph? Is the difference between Venous and arterial ph more than 0.02 Is the difference between the arterial pco2 and venous pco2 more than 0.5kPa? Is arterial po2 lower than venous po2? The results are accurate Inform midwife/doctor Document results in the medical records Repeat sampling Send a pair of samples to Buscot Samples mislabelled Recheck origin of samples Repeat sampling if origin not clear Repeat sampling Mixed sample or sampling of the same vessel Repeat sampling Mixed sample or sampling of the same vessel Repeat sampling? Air contamination Author: M Selinger, J Siddall, P Street March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 7 of 8

8 Fetal/cord blood sampling guideline March 2014 Monitoring The audit team that will audit the above auditable standards will be formed by: A midwife and/or a doctor and/or a maternity support worker Audit and quality midwife A clinical audit facilitator / assistant The audit will compare results with previous audits, if applicable. The audit will review documentation stated in the maternal health records as evidence of compliance with standards. The table below shows the plan to follow based on the audit results obtained. This would be subject to earlier re-audit if concerns are raised from risk management about this particular topic. Continuous and prospective audits might override this plan. Results Risk Priority Minimum Plan If < 75% compliance 1 Implement action plan and re-audit within 3 months from completion of report If 75% compliance and results than previous audit (when applicable) If 75% compliance and results than previous audit (when applicable) 2 3 Implement action plan and re-audit within 6 months from completion of report Implement action plan and re-audit next financial year from completion of report The results will be disseminated depending on the risk priority. Risk Priority Dissemination Reported in Maternity Audit Forum 1 Uploaded in Maternity Intranet page RBHFT Maternity Newsletter Special measures identified in action plan Summary reported in Maternity Audit Forum 2 Uploaded in Maternity Intranet page RBHFT Maternity Newsletter 3 Summary reported in Maternity Audit Forum RBHFT Maternity Newsletter The dissemination on results and implementation of action plans and timely re-audit will be coordinated by the Audit and Quality Midwife and reported to the Maternity Clinical Audit Committee on a quarterly basis. This committee reports to Maternity Clinical Governance quarterly. Author: M Selinger, J Siddall March 2014 This document is valid only on date Last printed 14/10/ :11:00 Page 8 of 8