Fetal Blood Lactate – PubMed Abstracts 2000-2005
Am J Obstet Gynecol. 1999 Nov;181(5 Pt 1):1072-8.
Predictive value of fetal scalp blood lactate concentration and pH as markers of
neurologic disability.
Kruger K, Hallberg B, Blennow M, Kublickas M, Westgren M.
Department of Obstetrics and Gynecology, Huddinge University Hospital, Karolinska
Institutet, Stockholm, Sweden.
OBJECTIVES: We aimed to analyze the predictive value of the fetal scalp blood
lactate concentration and pH, especially in regard to outcome variables that are strong
predictors of impaired long-term outcome. An additional aim was to establish cutoff
lactate levels in fetal scalp blood. STUDY DESIGN: We conducted a retrospective
study of all patients who had fetal scalp blood sampling performed because of an
ominous fetal heart rate pattern at Huddinge University Hospital from October 1993
to October 1998. Fetal scalp blood sampling was performed in 1709 patients. The pH
and the lactate concentration were determined in fetal scalp blood of 1221 and 814 of
these patients, respectively. Outcome variables included pH <7.0 in umbilical artery
blood; base deficit >16.0 mmol/L in umbilical artery blood; Apgar scores <7 at 1
minute, <7 at 5 minutes, and <4 at 5 minutes; and hypoxic-ischemic encephalopathy.
RESULTS: Sensitivity and specificity were generally higher in the lactate group than
in the pH group, particularly in relation to an Apgar score <4 at 5 minutes and
moderate to severe hypoxic-ischemic encephalopathy. In 326 patients the scalp blood
lactate concentration and pH value had been obtained at the same time, thus allowing
a comparison between these methods. The areas under the receiver operating
characteristic curves were significantly higher for the lactate concentration than for
the pH value with 2 outcome variables: Apgar score <4 at 5 minutes (P =.033) and
moderate to severe hypoxic-ischemic encephalopathy (P =.015). CONCLUSIONS:
Our findings suggest that determination of the lactate concentration in fetal scalp
blood is a more sensitive diagnostic tool than is determination of the pH value for
predicting either an Apgar score <4 at 5 minutes or moderate to severe hypoxicischemic encephalopathy. In previous studies we also showed lactate measurements to
be more often successful than pH analysis. Therefore we consider the measurement of
lactate in fetal scalp blood to be an attractive alternative to pH analysis, and
determination of the lactate concentration in fetal scalp blood seems to be a useful
tool for monitoring the condition of the fetus. A suitable cutoff limit for fetal scalp
blood lactate concentration as an indicator of fetal asphyxia could be 4.8 mmol/L.
Obstet Gynecol Clin North Am. 1999 Dec;26(4):641-56, vii.
Scalp blood gas analysis.
Greene KR.
Plymouth Perinatal Research Group, Postgraduate Medical School, University of
Plymouth, United Kingdom.
The use of fetal blood sampling has been advocated widely to improve the specificity
of fetal heart rate monitoring, but it remains a clinically unpopular procedure. This
article considers its physiologic rationale and evidence base. It includes descriptions
of the technique with suggestions for improved clinical interpretation and discusses
the efficacy of fetal blood sampling with some consideration of possible alternatives.
Curr Opin Obstet Gynecol. 2000 Apr;12(2):123-7.
Intrapartum fetal surveillance.
Jibodu OA, Arulkumaran S.
Department of Obstetrics and Gynaecology, Derby City Hospital, Derby, UK.
Intrapartum hypoxia was thought to contribute to the incidence of cerebral palsy,
seizures and mental retardation. Electronic fetal monitoring was expected to prevent
or reduce this incidence. Electronic fetal monitoring has a high false positive rate and
fetal blood sampling, which is an invasive procedure, only allows an intermittent
assessment. Efforts are being made to improve fetal heart rate analysis and clinical
management. Fetal pulse oximetry, fetal electrocardiogram waveform analysis and the
intermittent measurement of lactate levels by fetal blood sampling may become
established as an adjunct to electronic fetal monitoring.
Aust N Z J Obstet Gynaecol. 1999 May;39(2):227-33.
A new method for rapid measurement of lactate in fetal and neonatal blood.
Pennell CE, Tracy MB.
Department of Obstetrics and Gynaecology, University of Sydney, The Nepean
Hospital, Penrith, New South Wales, Australia.
A prospective trial to determine the accuracy and precision of the Boehringer
Mannheim Accusport handheld lactate meter in measuring plasma lactate levels in
umbilical cord blood and neonatal blood microsamples was performed in the labour
ward and the neonatal intensive care unit of the Nepean Hospital. Specimens were
collected from the umbilical artery of 160 consecutive deliveries covering gestations
from 26 to 42 weeks, and from 110 umbilical artery catheters covering a range of
gestations from 26 to 41 weeks. Serum was also obtained from an exchange
transfusion for coefficient of variation analysis. Blood was simultaneously tested for
lactic acid concentration on the Boehringer Mannheim (BM) Accusport held lactate
meter and the Radiometer ABL 625 blood-gas machine. Clinical data from the mother
and baby were recorded together with the full blood-gas analysis for comparison with
the lactate measures. Coefficients of variation for the BM Accusport lactate meter
were established by a further 120 samples of plasma lactate at 6 concentrations from 1
to 20 mmol/L. The stability of measurements with the BM lactate meter over a wide
range of temperatures was ascertained by repeated sampling of known concentrations
of plasma lactate from 0.5 degrees C to 37 degrees C. The BM Accusport lactate
meter was found to be accurate from 1 mmol/L to 20 mmol/L with a Passing Bablok
regression line y = 0.004 + 0.915 x (95% CI of slope of 0.889 to 0.946 and intercept 0.138 to 0.094) for whole blood, and y = 0.200 + 1.000 x (95% CI of slope 0.989 to
1.018 and intercept 0.080 to 0.222) for plasma. Between run coefficient of variation
(CV) was calculated to be 1.23% to 5.53% over the clinically significant range (2.219.3 mmol/L). The BM lactate meter was accurate from 5 to 37 degrees C. At 0.5
degrees C the BM lactate meter significantly underestimated the plasma lactate
concentration. There was no significant effect of haematocrit (41.5 to 62%), gestation,
or operator on the accuracy of the BM lactate meter. The Accusport handheld lactate
meter is an accurate, commercially available, method of measuring plasma lactate
levels in only 60 seconds at the point-of-care. It requires only 15 microL of blood and
is significantly cheaper than other assay methods. The BM lactate meter is well suited
to assess lactic acidaemia of fetal scalp and neonatal blood samples to help quantify
hypoxic stress in the perinatal period.
Curr Opin Obstet Gynecol. 2001 Apr;13(2):141-5.
Lactate measurements in scalp and cord arterial blood.
Nordstrom L.
Department of Obstetrics and Gynaecology, Karolinska Institute, Soder Hospital,
Stockholm, Sweden. lennart.nordstrom@kk.sos.sll.se
Lactate has been measured to evaluate fetal metabolic acidosis for some decades.
However, not until the past few years have reliable lactate meters become available
for bedside obstetric practice. The new technology, which requires only 5 microl
blood, has reduced the sampling failure rate of fetal scalp blood to almost nil. A
growing body of evidence has also shown lactate to be good at predicting neonatal
outcome.
Best Pract Res Clin Obstet Gynaecol. 2004 Jun;18(3):467-76.
Fetal scalp and cord blood lactate.
Nordstrom L.
Karolinska University Hospital, Solna, 17176 Stockholm, Sweden.
lennart.nordstrom@kus.se
Lactate measurements have been evaluated in intrapartum fetal surveillance for some
30 years. However, it was not until reliable, handheld, microvolume devices were
launched during the 1990s that lactate became a clinical option. Retrospective data
suggest that lactate determinations in fetal scalp blood are better than pH for
predicting severe neonatal morbidity. A randomised controlled trial comparing these
two measurements found lactate to be more favourable in clinical practice in terms of
less sampling failure and reduced time from the decision to do a fetal scalp blood
sample to the clinician receiving the result. At present, a large multicenter randomised
control trial is in progress in Sweden to compare lactate and pH measurement for the
clinical management of suspected fetal compromise. Main end-points in the study are
metabolic acidemia or pH <7.00 in cord arterial blood at delivery. Results are likely to
be available in 2-3 years time.
Aust N Z J Obstet Gynaecol. 2004 Dec;44(6):549-52.
Determining the fetal scalp lactate level that indicates the need for intervention
in labour.
Allen RM, Bowling FG, Oats JJ.
Mater Hospital, South Brisbane, Queensland, Australia. rodallen@hotmail.com
BACKGROUND: Fetal scalp lactate testing has been shown to be as useful as pH
with added benefits. One remaining question is 'What level of lactate should trigger
intervention in the first stage of labour?' AIMS: This study aimed to establish the
lactate level in the first stage of labour that indicates the need for intervention to
ensure satisfactory outcomes for both babies and mothers. METHODS: A prospective
study at Mater Mothers' Hospital, Brisbane, Australia, a tertiary referral centre. One
hundred and forty women in labour, with non-reassuring fetal heart rate traces, were
tested using fetal blood scalp sampling of 5 microL of capillary blood tested on an
Accusport (Boeringer, Mannheim, East Sussex, UK) lactate meter. Decision to
intervene in labour was based on clinical assessment plus a predetermined cut off.
Main outcome measures were APGAR scores, cord arterial pH, meconium stained
liquor and Intensive Care Nursery admission. RESULTS: Two-graph receiver
operating characteristic (TG-ROC) analysis showed optimal specificity, and
sensitivity for predicting adverse neonatal outcomes was a scalp lactate level above
4.2 mmol/L. CONCLUSIONS: Fetal blood sampling remains the standard for further
investigating-non-reassuring cardiotocograph (CTG) traces. Even so, it is a poor
predictor of fetal outcomes. Scalp lactate has been shown to be at least as good a
predictor as scalp pH, with the advantages of being easier, cheaper and with a lower
rate of technical failure. Our study found that a cut off fetal scalp lactate level of 4.2
mmol/L, in combination with an assessment of the entire clinical picture, is a useful
tool in identifying those women who need intervention.
Gynecol Obstet Fertil. 2005 Mar;33(3):107-12.
[Value of fetal scalp lactate sampling during labour: a comparative study with
scalp pH]
[Article in French]
Ramanah R, Martin A, Riethmuller D, Maillet R, Schaal JP.
Service de gynecologie-obstetrique, CHR Saint-Jacques, avenue du 8-Mai-1945,
25030 Besancon cedex, France.
OBJECTIVE: To evaluate the validity and the feasibility of fetal scalp lactate
sampling during labour in the assessment of non reassuring fetal status. PATIENTS
AND METHOD: A prospective observational study was conducted on 129 fetal scalp
blood samplings. Scalp lactate measurements were compared to scalp pH (gold
standard procedure), neonatal cord blood gas (pH and lactates) and Apgar score.
Pathological values taken were for scalp lactates>5 mmol/l, scalp pH<7.20, cord
arterial pH<7.10, cord arterial lactates>6,35 mmol/l, and Apgar score<7 at one and
five minutes. All measurements were performed using the Rapid Lab 860 device from
Bayer. RESULTS: Scalp lactate correlated significantly with scalp pH (R=-0.54,
P=0.001), with umbilical artery pH (R=-0.46, P=0,01), with umbilical artery lactate
(P=0.49, P=0.01), but with neither Apgar score at one minute (R=-0.21, ns) nor at 5
minutes (R=-0.11, ns). Scalp lactate at a cut-off value of 5 mmol/l had the same
predictive values than scalp pH at 7.20 to predict neonatal acidosis. Sampling failure
with scalp lactate was inferior to 1 vs 18% for scalp pH. DISCUSSION AND
CONCLUSION: The measurement of lactate in fetal blood scalp seems correlated to
the fetal scalp pH. It may be an attractive alternative to pH analysis and a useful tool
for monitoring fetal asphyxia, especially with the advent of handheld devices
requiring small sample volumes.