Transcript CTG Traces
1 Calibration of the CTG 2 Calibration of the CTG 3 Calibration of the CTG 4 Calibration of the CTG 5 Features and Terminology of CTG • The four main features of CTG are: ▫ ▫ ▫ ▫ Baseline rate. Baseline variability. Accelerations. Decelerations. 6 Baseline Fetal Heart Rate • Baseline rate is defined as the level of the fetal heart rate when it is stable, excluding accelerations and decelerations. • It is determined over a time of 5-10 minutes, and expressed in beats per minute. Reassuring: Normal baseline 110 – 160 Non-Reassuring: Moderate bradycardia Moderate tachycardia 100 – 109 161 – 180 Abnormal: Abnormal bradycardia Abnormal tachycardia < 100 > 180 7 Normal Baseline FHR 8 Baseline Bradycardia 9 Baseline Tachycardia 10 Baseline Variability • Baseline variability is the minor fluctuations in baseline fetal heart rate occurring over 3-5 cycles/minute. Reassuring: Normal baseline 5 bpm between contractions for up to 40 minutes Non-Reassuring: Non-reassuring baseline variability < 5 bpm for 40 minutes or more, but less than 90 minutes Abnormal: Abnormal baseline variability < 5 bpm for 90 minutes or more Note: if repeated accelerations are present with reduced variability, the CTG should be regarded as reassuring. 11 Normal Variability 12 Reduced Variability 13 Reduced Variability 14 Accelerations • Accelerations are abrupt, transient increase in fetal heart rate of 15 bpm, lasting for 15 seconds. • The absence of accelerations otherwise normal CTG is of significance. with an uncertain 15 Acceleration 16 Decelerations • Decelerations are a transient slowing of the fetal heart rate below the baseline of 15 bpm for 15 seconds. • There are 5 types of decelerations: ▫ ▫ ▫ ▫ ▫ Early deceleration Late deceleration Variable deceleration Atypical variable deceleration Prolonged deceleration • In addition, there are one specific pattern: ▫ Sinusoidal pattern 17 Early Decelerations • Uniform, repetitive, periodic slowing of the FHR with onset early in the contraction and return to baseline at the end of contraction. • The lowest point of the deceleration coincides with the highest point of the contraction wave. • Usually associated with head compression. • Tend to occur late in the first stage or during the second stage of labor. • Benign, not significant, not associated with fetal hypoxia. 18 Early Decelerations 19 Early Decelerations 20 Early Decelerations 21 Late Decelerations • Uniform, repetitive, periodic slowing of the FHR with onset mid- to the end of the contraction. • The lowest point of the deceleration more than 20 seconds after the peak of the contraction wave, always ending after the contraction. • In non-accelerative trace, with baseline variability < 5 bpm, the definition would include decelerations < 15 bpm. • Late decelerations, if present for > 30 minutes, are always indicative of fetal hypoxia, and further action is indicated. 22 Late Decelerations 23 Late Decelerations 24 Late Decelerations 25 Variable Decelerations • The MOST COMMON form of decelerations occurring during labor. • Variable, intermittent, periodic slowing of the FHR, with rapid onset and recovery. • Time relationships with contraction waves are variable. Sometimes, they may resemble other types of decelerations in timing and shape. 26 Variable Decelerations – cont’d • Variable decelerations are often caused by umbilical cord compression. • Variable decelerations are either typical or atypical. • Typical variable decelerations are an autonomic nervous system response to cord compression and are indicative of the fetus coping well. 27 Variable Decelerations – cont’d • However, the fetus may become tired over time and, if typical variable decelerations occur with over 50% of contractions for more than 90 minutes, this should be regarded as nonreassuring, particularly if there is any degree of fetal compromise such as fetal growth restriction. • Atypical variable decelerations may subsequently develop indicating that the fetus is now less able to cope with cord compression. 28 Pure (Typical) Variable Decelerations 29 Prolonged Decelerations • An abrupt decrease in FHR to levels below the baseline that lasts at least 60-90 seconds. • If fetal bradycardia occurs for more than 3 minutes, plan should be made to urgently expedite delivery. A “category 1” birth should be declared and the woman should be immediately transferred to the theatre. If the fetal heart rate recovers within 9 minutes, the decision for immediate delivery should be reconsidered, if reasonable, and in consultation with the woman. 30 Prolonged Decelerations 31 Sinusoidal Pattern • A regular oscillation of the baseline long-term variability (resembling a sine wave). • Smooth, undulating pattern, lasting at least 10 minutes, has a relatively fixed period of 3-5 cycles per minute at an amplitude of 5-15 beats per minute above and below the baseline. • Baseline variability is absent. • A true sinusoidal pattern is an abnormal feature and is associated with high rates of fetal morbidity and mortality. 32 Sinusoidal Pattern 33 Intrapartum CTG Baseline rate Reassuring 110 – 160 bpm Non-Reassuring •100 – 109 bpm •161 – 180 bpm < 5 bpm for 40-90 min (in absence of accelerations) Abnormal •< 100 bpm •> 180 bpm •Sinusoidal pattern for min Comments: 10 Variability 5 bpm or more < 5 bpm for 90 minutes (in absence of accelerations) Accelerations present Decelerations None •Typical variable decelerations with > 50% of contractions for over 90 minutes •Single prolonged decelerations up to 3 minutes •Atypical variable decelerations > 50% of contractions for over 30 minutes •Single prolonged deceleration > 3 minutes Opinion Normal CTG (all 4 features reassuring) Suspicious CTG (one non-reassuring feature) Pathological CTG (two or more non-reassuring, or one or more abnormal features) Cervical Dilatation Cont’s Comments: : 10 min Liquor Color Gestational Age Comments: Maternal Pulse Action Date: Time: Comments: Signature: Status: