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Cardiotocography and medicolegal issues
Best Practice & Research Clinical Obstetrics and Gynaecology Vol. 18, No. 3, pp. 457–466, 2004 doi:10.1016/j.bpobgyn.2004.02.005 available online at http://www.sciencedirect.com
7 Cardiotocography and medicolegal issues Bode Williams
MRCOG
Clinical Senior Lecturer in Obstetrics and Gynaecology
S. Arulkumaran*
FRCOG
Professor in Obstetrics and Gynaecology Department of Obstetrics and Gynaecology, St George’s Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK
Obstetric litigation is on the increase. A review of litigation cases reveals that the majority of claims relating to the intrapartum period arise because the cardiotocograph- (CTG) was misinterpreted or because inappropriate action was taken in the presence of fetal heart rate abnormalities. Compulsory education and training in the interpretation of CTGs and in best practice are key factors in minimizing the threat of litigation. Newer methods, such as pulse oximetry or fetal electrocardiogram waveform analysis, can act as adjuncts to CTG and help to avoid birth asphyxia and hence litigation. Key words: cardiotocograph; litigation; obstetrics; intrapartum.
SETTING THE SCENE Obstetric litigation is a growing problem in Western countries and its escalating cost, together with the increase of medical malpractice insurance premiums, is a major concern for maternity service providers. In England, litigation arising from maternity services accounts for 60– 70% of the total sum paid out by the NHS litigation authority, but comprises only 26% of the workload.1 The main reason for this disproportion is because claims relating to cerebral palsy and hypoxic brain injuries involve very large settlements. Nowadays, settlements are uncapped. A severely brain damaged child who requires constant nursing care might be awarded over £1 million in damages, for the cost of future care and loss of income. The publicity generated can also attract other people towards litigation. Apart from financial compensation, patients resort to legal action because they want to find out what happened, why this occurred and to prevent future recurrence.2 * Corresponding author. Tel.: þ44-208-725-5959; Fax: þ44-208-725-5958. E-mail address: [email protected] (S. Arulkumaran). 1521-6934/$ - see front matter Q 2004 Elsevier Ltd. All rights reserved.
458 B. Williams and S. Arulkumaran
It is recognised that many more cases of adverse events arise during the intrapartum period than proceed to legal action. Furthermore, any adverse event involves severe mental distress to patients and caregivers. Although this is difficult to express in monetary terms, it is probably much greater than the cost of litigation.3 It appears that the root of the problem is the scale of preventable adverse events and not the threat of litigation.
CARDIOTOCOGRAPHY: BLESSING OR CURSE? For many years, it was assumed that birth asphyxia was the principal cause of cerebral palsy (CP). Indeed, when cardiotocography (CTG) was introduced in 1970s it was hoped that this technique would reduce the incidence of cerebral palsy and mental retardation by 50%. Disappointingly, the results of randomised trials showed little or no benefit with respect to long-term neurological outcome, despite widespread use of the CTG. Recent studies have shown that only around 3-20% of cases of CP are associated with intrapartum asphyxia.4 As a result, some obstetricians are questioning the value of intrapartum CTG monitoring because of its poor predictive value for CP, claims of overuse and rising rates of caesarean section. However, the CTG is now an integral part of intrapartum care in most delivery suites and it is helpful in identifying asphyxiating conditions during labour in a small group of babies at risk of death or irreversible brain injury. CTG remains the central documentary evidence for all claims for fetal asphyxia. In a review of 110 cases of obstetric litigation for cerebral palsy, Symond and Senior found that 70% of these claims were based on abnormalities of the CTG and their interpretation.5 Analysis of claims for alleged negligence have shown that the recurring theme in most litigation cases can be laid down to the following factors: † † † † † † †
misinterpretation of CTG tracing inappropriate action or delayed response technique and equipment problems inappropriate use of oxytocin record keeping and communication issues poor supervision inadequate staffing.6,7
These factors were also identified in the majority of cases of ‘intrapartum-related’ deaths of normally formed babies in the fourth CESDI report, which found that more than 50% of cases of perinatal deaths were due to avoidable errors despite fetal monitoring.8
PREVENTING ERRORS Errors commonly observed in CTG interpretation are directly related to the quality of the data acquisition and the presentation by the CTG machine. It is therefore crucial
Cardiotocography and medicolegal issues 459
that all obstetricians and midwives understand the reasons for erroneous recordings and recognise the limitations of the technique. The potential pitfalls are outlined below, with suggestions on how to avoid them. Patient identification The name of the woman, the date and time of commencement should be entered on every trace. The time is automatically recorded on new CTG machines but the clock on these machines must always be checked. The time at the end of the trace must also be recorded. If monitoring extends beyond one pack of paper, the packs should be labelled Part 1, 2, 3, etc. The timing and order of events is often crucial in Court and commonly disputed areas in cases of fetal compromise are the timing of intervention and what is an acceptable time delay from the time of decision-making to delivery. Recording of maternal pulsation This is a common source of error. To avoid it, the Medical Device Agency has advised that the fetal heart rate (FHR) should be auscultated prior to application of the electronic FHR monitor. In addition, the maternal pulse should be identified and recorded separately. It also helps to ensure that the optimal area for transducer placement is selected before securing the elastic strap. A well-recognised scenario is the case of a dead baby where maternal vessel pulsation, detected by the ultrasound transducer, or the maternal ECG complex, transmitted via the scalp electrode, mimicks a normal fetal heart trace. When there is any doubt, fetal demise should be confirmed by real-time ultrasound to avoid such distressing situations. During labour, the whole CTG trace should be reviewed at regular intervals for any sudden significant shift in the baseline FHR, which could indicate that the maternal pulse rather than the fetal pulse is being recorded. This situation might occur if the ultrasound transducer slips out of position with maternal movements or in the case of twins, where the transducer starts to record the maternal pulse after delivery of the first twin. To avoid this error, check the FHR of the second twin by auscultation and adjust the transducer position if necessary. Poor-quality erratic tracing The FHR tracing becomes difficult to interpret if there is persistent signal loss or if the tocograph ceases to record contractions for a significant period of time. The situation should be corrected by changing the transducer, electrode, connections and/or machine. If these actions do not rectify the problem, intermittent auscultation should be performed and this should be documented in the medical records. The Courts will view an uninterpretable CTG with utmost suspicion and such a recording might jeopardise a successful defence. CTG storage The secure storage and preservation of CTG tracings for an indefinite period is a matter of concern for many units, given that a claim on behalf of a child can be
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brought within 21 years of birth or longer if the child is not legally capable of managing his or her own affairs. CTG papers are thermosensitive and tend to fade within 3-4 years. Another major problem is missing CTG traces. A review of litigation cases found that around 30% of traces were missing and that another 20% could not be interpreted.9 One solution is to employ electronic storage systems. CTG tracings can be downloaded and stored online in powerful central servers. Other systems make use of write-once-read-many-times (WORM) optical disks that can archive 4000 cases, with an average of 8 hours of trace, along with the clinical data. Storage of disks on shelves makes more economic sense than a storehouse holding 100 000 case notes. Apart from providing a robust way of storage, electronic systems facilitate easy retrieval, research and audit. Misreading CTGs CTG misinterpretation is the most common source of alleged negligence in obstetric litigation and the inexact nature of CTG traces causes great confusion in Court. There is little doubt that CTG interpretation is subject to variation outside the perfectly normal and grossly abnormal traces, even among obstetric experts. However, CTG interpretation can be improved with formal education and training. The best way to achieve competence in CTG interpretation is probably through a combination of strategies rather than a single approach: † It is essential that all maternity units provide a regular and structured programme of compulsory training on the interpretation of CTGs for all midwives and doctors. † Induction/educational programmes should include mandatory introductory training whenever an individual takes up a new post. † Regular rolling ‘CTG study days’ every 6 months will ensure that all staff keep up to date. Ideally, these sessions should be ‘protected from clinical work’ to maximise attendance. † All midwives and doctors should be encouraged to participate in weekly case review meetings, as this is the best way of reinforcing knowledge. † Self-directed learning should be encouraged. Units should provide learning resources such as books, interactive CD-ROMs or access to websites. Inaction with suspicious or abnormal CTG Inaction is a common feature in many claims. An abnormal CTG is considered to indicate a risk of fetal hypoxia, it is indefensible to take no action and, indeed, it is not acceptable practice. An appropriate action might include a decision to ‘wait and see’ for a limited period while taking remedial actions such as repositioning the woman, stopping oxytocin, using tocolysis (e.g. terbutaline 0.25 mg subcutaneous in the presence of hyperstimulation) or improving placental perfusion by maternal hydration. A fetal scalp blood sample might be obtained if the cervix is sufficiently dilated. Based on the clinical situation, immediate delivery might be the only option. The time of observation and the action taken including a decision to ‘wait and see’ should be recorded in the notes. Initialling the CTG is not enough and if a decision that has been taken is not clearly documented in the notes it will appear in retrospect that the CTG abnormality was simply ignored.
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With persisting FHR abnormalities, the scalp blood samples should be repeated within 30 minutes even if the previous results were normal. Time is of the essence in cases of prolonged FHR bradycardia because hypoxia and acidosis can develop rapidly. In such cases, especially if the bradycardia is due to placental abruption, cord prolapse or scar dehiscence, an immediate caesarean section should be performed, ideally within 15 minutes and certainly no longer than 30 minutes. There is a strong correlation between poor neonatal outcome and a delayed decision to deliver. Experienced paediatric personnel, skilled in neonatal intubation, should attend the delivery if resuscitation is anticipated. The promptness and efficiency of neonatal resuscitation might be critical in determining the subsequent fate of the infant. Unrecognised oxytocin hyperstimulation A common problem in litigation cases is oxytocin-induced hyperstimulation leading to prolonged decelerations, aggravation of existing late or variable decelerations, uterine rupture, fetal hypoxia and brain damage. This situation tends to occur when the monitoring of contractions is inadequate. It can allow excessive uterine activity to continue unrecognised, thus delaying the appropriate response to decrease or discontinue oxytocin. The only effective strategy to prevent claims based on unrecognised oxytocin hyperstimulation is to be meticulous in detecting uterine contractions. Contractions are most conveniently monitored externally with a tocodynamometer.10 Prior to commencing oxytocic agents, the nature of the uterine contraction should be recorded. There should be a clear labour-ward policy for oxytocin regimen. It goes without saying that with excessive uterine activity oxytocin should be stopped or discontinued. Furthermore, oxytocin should be discontinued in the presence of an abnormal FHR pattern and should only be restarted if the FHR becomes normal or if acidosis is excluded by scalp blood sampling. Oxytocin infusion rates in excess of 8 – 12 milliunits/minute can result in significant hyperstimulation; therefore dosage increments should be approached with caution. Oxytocin should be used with caution in the presence of a previous uterine scar because it is more common for such scars to rupture with oxytocin augmentation or induction of labour than during spontaneous labour.11 It is difficult to defend a case of a ruptured uterus successfully when oxytocin was used, unless there is clear evidence that uterine activity was monitored adequately, that it did not show hyperstimulation and that prompt action was taken on clinical suspicion or abnormal FHR findings suggestive of impending scar rupture. Failure to incorporate the clinical picture It must always be borne in mind that the CTG is only an investigation and that monitoring labour using only a single parameter is never sufficient. With any given CTG, the clinical actions and decisions will vary depending on the clinical picture. For instance, an abnormal CTG showing fetal tachycardia with atypical variable or late decelerations and reduced variability at 3 – 4 cm in a primigravid might warrant a caesarean section, whereas at 7– 8 cm it might indicate the need for fetal scalp blood sampling and an instrumental delivery in the second stage, if this can be carried out safely. Other clinical risk factors, such as thick meconium with scanty fluid, intrauterine growth restriction or intrauterine infection, cause a rapid decline in pH with
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an abnormal CTG and warrant early action. When there is abruption, cord prolapse or possible scar rupture, a suboptimal CTG needs immediate intervention because these traces can suddenly change for the worse, resulting in a poor outcome.10 The clinical picture should always have a major influence on the action planned on the face of a disquieting CTG.
RELATED ISSUES Fetal scalp blood sampling All maternity units where CTG is employed should have ready access—24 hours a day—to an accurate microblood gas analyzer. CTG is an imperfect tool and many of the indicators used to identify early hypoxia are non-specific. Thus, if CTG is used as the sole method of intrapartum fetal surveillance, unnecessary operative deliveries will be performed.12 Fetal scalp blood sampling should therefore be performed in the presence of abnormal FHR patterns unless the CTG and/or the clinical picture demand immediate delivery. The correct equipment and optimum positioning of the woman for fetal blood sampling is very important. Once fetal scalp sampling has been done, pressure with a swab to the site of the puncture should stop the bleeding. After the amnioscope has been withdrawn, the mother must be observed to exclude significant fetal haemorrhage from the scalp puncture site. Two fetal blood samples taken at a 30-minute interval might be required to determine the rate of decline in the pH, in the face of persisting FHR abnormalities. If the rate of decline in the pH indicates possible fetal acidosis prior to the anticipated time of birth, then the delivery should be expedited. Immediate delivery is indicated if the pH is less than 7.20.13 The use of bedside fetal lactate measurement (using 5 ml of blood) to better define metabolic acidosis is becoming more popular.14 This will also reduce the number of cases in which the FBS tests are abandoned because of insufficient samples. Umbilical cord artery blood acid–base analysis In the current climate, any mishap in the delivery room has the potential to become a litigation case. For instance, the parents of a baby born with a low Apgar score and who required assisted ventilation might take legal action at a later date if the child develops neurological problems. However, the Apgar score was designed to assess the need and extent of resuscitation needed by a newborn, and a low Apgar score is poor at defining asphyxia; there are many other causes. Obstetric experts involved in litigation cases of birth asphyxia suggest that the Apgar score is a subjective evaluation and might be biased by the attending staff in the delivery room. This view is supported by both the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, who have challenged the use of Apgar score to define birth asphyxia. Various criteria has been set by national colleges and other groups to define the term ‘birth asphyxia’. The following essential and/or additional criteria were recently suggested by a group meeting in Australia.15
Cardiotocography and medicolegal issues 463
Essential criteria † profound umbilical artery metabolic acidemia (pH , 7.0 and base deficit BD . 12) † early onset of severe or moderate encephalopathy in infants . 34 weeks † cerebral palsy of a spastic quadriplegic or dyskinetic type Additional criteria † † † † †
A sentinel hypoxic event occurring immediately before or during labour. A sudden rapid sustained deterioration in FHR pattern. Apgar scores of , 7 after 5 minutes. Early evidence of multi-organ ischaemic injury. Early evidence of acute cerebral involvement.
A useful way of ruling out the diagnosis of birth asphyxia in a depressed newborn is to analyse the umbilical cord arterial blood gases. This technique is simple, convenient and provides objective assessment of the newborn’s condition at delivery.16 The umbilical cord arterial blood gas result could potentially reduce the risk of litigation and associated expenses by excluding birth asphyxia if cerebral palsy is diagnosed later.17 Many maternity units now routinely determine umbilical cord arterial and venous blood acid – base status on all deliveries.18 However, this approach has a cost implication. If, for reasons of cost, sampling is done on a selective basis, then the cord arterial blood pH and base deficit should be determined in cases where there has been any concern during labour, operative deliveries (especially those for suspected fetal compromise), cases where a fetal scalp blood sample was done, those who had abnormal traces, those with moderate and thick meconium-stained amniotic fluid, who had bleeding in labour, preterm infants, multiple gestations, vaginal breech deliveries and the depressed infant at birth.
CLINICAL RISK MANAGEMENT The ultimate aim of clinical risk management is to improve the standard of patient care. Improvements in the standard of practice and enhancement in patient safety brought about by this process should, in theory, minimise litigation. The process begins with the identification of critical incidents and adverse outcomes, establishing why and where things went wrong (root-cause analysis of events can help distinguish between ‘active failures’ of individual practitioners and ‘latent failures’ within the organisation). Lessons learned from this analysis, and any subsequent recommendations, should be disseminated to all relevant staff to prevent a recurrence.19 The main stimulus for the recent increase in clinical risk management activity seems to be an attempt by health service providers to curb the spiralling cost of obstetric litigation.20 Many maternity units in the UK have now formed Clinical Risk Management (CRM) groups of senior representatives from the various disciplines, hospital management and the legal team. A typical group might consist of a Lead Obstetrician, Clinical Director, Delivery Suite Manager, Clinical Risk Co-ordinator, Paediatrician, Obstetric Anaesthetist and Hospital Litigation Officer. Meeting once a fortnight or once a month, a CRM group will review incidents that have given rise to complications based on agreed list of adverse events that might give rise to litigation. This allows an initial investigation to be carried out as
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soon as possible after an adverse event and for the relevant staff to be asked to produce a statement of their involvement to supplement the existing medical records while the evidence is still fresh in their minds. The process should not focus on questions of attribution and individual staff must not be called before the group, otherwise the clinical staff might feel the process to be punitive and be less inclined to report adverse incidents. The downside is the difficulty with putting any policy action into practice. In-house educational programmes or ‘study days’ can help raise the level of awareness of any recommendations and thus prevent a recurrence. Most importantly, a successful process should engender a sense of ownership among the staff. Another important function of the CRM group is to instigate audit standards of clinical care and adverse outcomes. Audit of low arterial cord pH in newborns, admission to neonatal unit, the need for assisted ventilation and the decision-todelivery interval for emergency caesarean sections for presumed fetal compromise are some of the topics that can be used to identify suboptimal practices and organisational problems that contribute to adverse outcomes even where these do not prompt legal action. Rapid review of adverse incidents, audits and continuing educational programmes are likely to achieve a reduction in litigation by identifying weaknesses and putting remedial processes in place.
CAUSATION AND LIABILITY The crucial first step for successful legal action is to establish causation. The question to consider is whether brain injury is a direct consequence of intrapartum asphyxia. The essential requirements for this are an abnormal CTG, evidence of severe perinatal asphyxia (i.e. arterial cord pH , 7.0), a depressed newborn requiring intensive resuscitation, neonatal neurological sequelae and evidence of multiorgan system dysfunction. If the CTG was normal, or the cause of neonatal encephalopathy remains unclear, then the Paediatric Neurologist should be asked to exclude a host of metabolic, genetic and infectious causes of neurological impairment. An accurate diagnosis of the underlying disorder is ultimately in the child’s best interest. If the history is suggestive of severe perinatal asphyxia then the focus will shift to the question of liability. The medical records will be scrutinised to determine whether the standard of care fell short of acceptable practice and whether appropriate action was taken in the presence of an abnormal CTG. The timing of intervention and the definition of acceptable practice are major areas of disputes. Liability is usually judged on what a reasonably competent practitioner would have done (the Bolam test). According to the Bolam principle: The test is the standard of the ordinary skilled man exercising and professing to have the specialist skill. A man need not possess the highest expert skill to be at risk of being found negligent. If a breach in the standard of care is established then compensation will be awarded.21 The Bolitho principle is increasingly being used, especially in cases in which there is an unresolved dispute among medical experts as to whether liability is due to omission or commission of care by the practitioner. According to the Bolitho principle:
Cardiotocography and medicolegal issues 465
If it can be demonstrated that the professional opinion is not capable of withstanding logical analysis, the judge is entitled to hold that the body of opinion is not reasonable or responsible.
CONCLUSION The threat of litigation is said to be the obstetrician’s and the midwife’s worst nightmare. The anguish of being involved in litigation can have long-term consequences on the working lives of these practitioners. On the other hand, everyone has sympathy for the parents with a handicapped child, nothing can compensate for the grief and the enormous burden that such a tragedy imposes on the rest of the family. Rapid investigation and prompt discussion of events would allay parental anger. If causation and liability were proven beyond doubt, it would be worthwhile settling these cases out of Court. Unfortunately, obstetric litigation will continue to rise. Nowadays parents expect to give birth to a healthy baby and if the baby is born with neurological deficits parents and their advisors believe that someone is to blame. The CTG is here to stay, despite the ongoing debate about its widespread application. Additional methods of intrapartum fetal monitoring are in early clinical use. However, most of these methods are used in conjunction with the CTG, hence the importance of learning about CTG interpretation. The other monitoring modalities currently in use are discussed elsewhere in this issue. The challenge facing perinatal healthcare professionals is how to achieve optimal maternal and neonatal outcomes without resorting to defensive practice. Structured and compulsory training in CTG interpretation for all midwives and doctors, good practice and good communication, and the use of adjuncts such as FBS for pH and blood gases or lactate, pulse oximetry or fetal ECG waveform analysis will play an important role in reducing adverse events and avoiding litigation. Better education of the public about the limitations of the technology would also help to reduce the gap between expectations and outcomes. Practice points All maternity units should have the following in place: † regular and compulsory training in the interpretation of CTG for all staff involved in intrapartum care † guidelines on CTG interpretation and appropriate management options for abnormal CTG in spontaneous, augmented and induced labour † an effective and reliable way of record keeping and CTG storage. Electronic archiving systems can help solve this problem † ready access to fetal scalp blood sampling or measured introduction of adjunctive methods of fetal surveillance † measurement of umbilical cord artery blood pH in deliveries where there was concern for the fetus during labour, operative/difficult deliveries or when the neonate’s condition at delivery is suboptimal † a mechanism for the rapid review of adverse events and dissemination of recommendations † regular audit of adverse outcomes
466 B. Williams and S. Arulkumaran
Research agenda † evaluate the impact of CTG education on improvement in clinical outcome † improve computerised interpretation of intrapartum CTGs to increase the sensitivity and specificity (e.g. evaluation of short-term variability) † assess neonatal outcome related to incident/insult-to-delivery interval compared with decision-to-delivery interval † evaluate the possible mechanisms of fetal neurological injury
REFERENCES 1. Hepworth S. Clinical cases by speciality. NHS Litigation Authority Journal 2003; Summer(issue 2): 4. 2. Vincent C, Young M & Phillips A. Why do people sue doctors? A study of patients and relatives taking legal action. Lancet 1994; 343: 1609–1613. 3. Dingwall R & Fenn P. Risk management: financial implications. BMJ 1995; : 73–87. 4. Nelson KB & Ellenberg JH. Antecedents of cerebral palsy. Multivariate analysis of risk. New England Journal of Medicine 1986; 315: 81–86. 5. Symonds EM & Senior EO. The anatomy of obstetric litigation. Current Opinion in Obstetrics and Gynecology 1991; 1: 241–243. 6. Capstick B & Edwards P. Trends in obstetric malpractice. Lancet 1990; 336: 931–932. 7. Ward CJ. Analysis of 500 obstetric and gynaecologic malpractice claims: causes and prevention. American Journal of Obstetrics and Gynecology 1991; 165: 298– 304. 8. Confidential Enquiry into Stillbirths and Deaths in Infancy. 4th Annual Report. 1997. Maternal and child Health Research Consortium. 9. Ennis M & Vincent CA. Obstetric accidents: a review of 64 cases. BMJ 1990; 300: 1365–1367. 10. Gibb DMF & Arulkumaran S. Fetal Monitoring in Practice. Oxford: Butterworth Heinemann, 1997. 11. Chua S & Arulkumaran S. Trial of scar. Australian and New Zealand Journal of Obstetrics and Gynaecology 1997; 37: 6–11. 12. Neilson JP. Fetal blood sampling as adjunct to heart rate monitoring. In Enkin MW, Keirse MJ, Renfrew MJ & Neilson JP (eds) Pregnancy and Childbirth Module of the Cochrane Database of Systematic Reviews. Cochrane Collaboration, Issue 2. Oxford: Oxford Update Software, 1995. 13. Royal College of Obstetricians and Gynaecologists 2001. The use of electronic fetal heart rate monitoring. National Institute of Clinical Excellence, clinical guidelines. Evidenced-based Clinical Guideline No 8. RCOG Clinical Effectiveness Support Unit, London, p. 14. 14. Nordstrom L, Ingemarsson I, Kublickas M, Persson B, Shimojo N & Westgren M. Scalp blood lactate: a new test strip method for monitoring fetal well-being in labour. British Journal of Obstetrics and Gynaecology 1995; 102: 894 –899. 15. MacLennan A. A template for defining a causal relation between acute intrapartum events and cerebral palsy: international consensus statement. BMJ 1999; 319: 1054–1059. 16. Johnson JW, Richards DS & Wagaman RA. The case for routine umbilical blood acid-base studies at delivery. American Journal of Obstetrics and Gynaecology 1990; 162: 621 –625. 17. Thorp JA, Sampson JE, Parisi VM & Creasy RK. Routine umbilical cord blood gas determinations? American Journal of Obstetrics and Gynaecology 1989; 161: 600–605. 18. Waugh J, Johnson A & Farkas A. Analysis of cord blood gas at delivery: questionnaire study of practice in the United Kingdom. BMJ 2001; 323: 727. 19. Capstick B. Risk management in obstetrics. In Clements RV (ed.) Safe practice in Obstetrics and Gynaecology. Edinburgh: Churchill Livingstone, 1994, pp 405–416. 20. Symon A. Obstetric Litigation from A-Z. Quay Books Division. Wiltshire, UK: Mark Allen Publishing Ltd, 2001. 21. Sanderson IM. Claims management: a guide for hospital claims manager. In Vincent C (ed.) Clinical Risk Management. London: BMJ Publishing, 1995, pp 492 –520.
7 Cardiotocography and medicolegal issues Bode Williams
MRCOG
Clinical Senior Lecturer in Obstetrics and Gynaecology
S. Arulkumaran*
FRCOG
Professor in Obstetrics and Gynaecology Department of Obstetrics and Gynaecology, St George’s Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK
Obstetric litigation is on the increase. A review of litigation cases reveals that the majority of claims relating to the intrapartum period arise because the cardiotocograph- (CTG) was misinterpreted or because inappropriate action was taken in the presence of fetal heart rate abnormalities. Compulsory education and training in the interpretation of CTGs and in best practice are key factors in minimizing the threat of litigation. Newer methods, such as pulse oximetry or fetal electrocardiogram waveform analysis, can act as adjuncts to CTG and help to avoid birth asphyxia and hence litigation. Key words: cardiotocograph; litigation; obstetrics; intrapartum.
SETTING THE SCENE Obstetric litigation is a growing problem in Western countries and its escalating cost, together with the increase of medical malpractice insurance premiums, is a major concern for maternity service providers. In England, litigation arising from maternity services accounts for 60– 70% of the total sum paid out by the NHS litigation authority, but comprises only 26% of the workload.1 The main reason for this disproportion is because claims relating to cerebral palsy and hypoxic brain injuries involve very large settlements. Nowadays, settlements are uncapped. A severely brain damaged child who requires constant nursing care might be awarded over £1 million in damages, for the cost of future care and loss of income. The publicity generated can also attract other people towards litigation. Apart from financial compensation, patients resort to legal action because they want to find out what happened, why this occurred and to prevent future recurrence.2 * Corresponding author. Tel.: þ44-208-725-5959; Fax: þ44-208-725-5958. E-mail address: [email protected] (S. Arulkumaran). 1521-6934/$ - see front matter Q 2004 Elsevier Ltd. All rights reserved.
458 B. Williams and S. Arulkumaran
It is recognised that many more cases of adverse events arise during the intrapartum period than proceed to legal action. Furthermore, any adverse event involves severe mental distress to patients and caregivers. Although this is difficult to express in monetary terms, it is probably much greater than the cost of litigation.3 It appears that the root of the problem is the scale of preventable adverse events and not the threat of litigation.
CARDIOTOCOGRAPHY: BLESSING OR CURSE? For many years, it was assumed that birth asphyxia was the principal cause of cerebral palsy (CP). Indeed, when cardiotocography (CTG) was introduced in 1970s it was hoped that this technique would reduce the incidence of cerebral palsy and mental retardation by 50%. Disappointingly, the results of randomised trials showed little or no benefit with respect to long-term neurological outcome, despite widespread use of the CTG. Recent studies have shown that only around 3-20% of cases of CP are associated with intrapartum asphyxia.4 As a result, some obstetricians are questioning the value of intrapartum CTG monitoring because of its poor predictive value for CP, claims of overuse and rising rates of caesarean section. However, the CTG is now an integral part of intrapartum care in most delivery suites and it is helpful in identifying asphyxiating conditions during labour in a small group of babies at risk of death or irreversible brain injury. CTG remains the central documentary evidence for all claims for fetal asphyxia. In a review of 110 cases of obstetric litigation for cerebral palsy, Symond and Senior found that 70% of these claims were based on abnormalities of the CTG and their interpretation.5 Analysis of claims for alleged negligence have shown that the recurring theme in most litigation cases can be laid down to the following factors: † † † † † † †
misinterpretation of CTG tracing inappropriate action or delayed response technique and equipment problems inappropriate use of oxytocin record keeping and communication issues poor supervision inadequate staffing.6,7
These factors were also identified in the majority of cases of ‘intrapartum-related’ deaths of normally formed babies in the fourth CESDI report, which found that more than 50% of cases of perinatal deaths were due to avoidable errors despite fetal monitoring.8
PREVENTING ERRORS Errors commonly observed in CTG interpretation are directly related to the quality of the data acquisition and the presentation by the CTG machine. It is therefore crucial
Cardiotocography and medicolegal issues 459
that all obstetricians and midwives understand the reasons for erroneous recordings and recognise the limitations of the technique. The potential pitfalls are outlined below, with suggestions on how to avoid them. Patient identification The name of the woman, the date and time of commencement should be entered on every trace. The time is automatically recorded on new CTG machines but the clock on these machines must always be checked. The time at the end of the trace must also be recorded. If monitoring extends beyond one pack of paper, the packs should be labelled Part 1, 2, 3, etc. The timing and order of events is often crucial in Court and commonly disputed areas in cases of fetal compromise are the timing of intervention and what is an acceptable time delay from the time of decision-making to delivery. Recording of maternal pulsation This is a common source of error. To avoid it, the Medical Device Agency has advised that the fetal heart rate (FHR) should be auscultated prior to application of the electronic FHR monitor. In addition, the maternal pulse should be identified and recorded separately. It also helps to ensure that the optimal area for transducer placement is selected before securing the elastic strap. A well-recognised scenario is the case of a dead baby where maternal vessel pulsation, detected by the ultrasound transducer, or the maternal ECG complex, transmitted via the scalp electrode, mimicks a normal fetal heart trace. When there is any doubt, fetal demise should be confirmed by real-time ultrasound to avoid such distressing situations. During labour, the whole CTG trace should be reviewed at regular intervals for any sudden significant shift in the baseline FHR, which could indicate that the maternal pulse rather than the fetal pulse is being recorded. This situation might occur if the ultrasound transducer slips out of position with maternal movements or in the case of twins, where the transducer starts to record the maternal pulse after delivery of the first twin. To avoid this error, check the FHR of the second twin by auscultation and adjust the transducer position if necessary. Poor-quality erratic tracing The FHR tracing becomes difficult to interpret if there is persistent signal loss or if the tocograph ceases to record contractions for a significant period of time. The situation should be corrected by changing the transducer, electrode, connections and/or machine. If these actions do not rectify the problem, intermittent auscultation should be performed and this should be documented in the medical records. The Courts will view an uninterpretable CTG with utmost suspicion and such a recording might jeopardise a successful defence. CTG storage The secure storage and preservation of CTG tracings for an indefinite period is a matter of concern for many units, given that a claim on behalf of a child can be
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brought within 21 years of birth or longer if the child is not legally capable of managing his or her own affairs. CTG papers are thermosensitive and tend to fade within 3-4 years. Another major problem is missing CTG traces. A review of litigation cases found that around 30% of traces were missing and that another 20% could not be interpreted.9 One solution is to employ electronic storage systems. CTG tracings can be downloaded and stored online in powerful central servers. Other systems make use of write-once-read-many-times (WORM) optical disks that can archive 4000 cases, with an average of 8 hours of trace, along with the clinical data. Storage of disks on shelves makes more economic sense than a storehouse holding 100 000 case notes. Apart from providing a robust way of storage, electronic systems facilitate easy retrieval, research and audit. Misreading CTGs CTG misinterpretation is the most common source of alleged negligence in obstetric litigation and the inexact nature of CTG traces causes great confusion in Court. There is little doubt that CTG interpretation is subject to variation outside the perfectly normal and grossly abnormal traces, even among obstetric experts. However, CTG interpretation can be improved with formal education and training. The best way to achieve competence in CTG interpretation is probably through a combination of strategies rather than a single approach: † It is essential that all maternity units provide a regular and structured programme of compulsory training on the interpretation of CTGs for all midwives and doctors. † Induction/educational programmes should include mandatory introductory training whenever an individual takes up a new post. † Regular rolling ‘CTG study days’ every 6 months will ensure that all staff keep up to date. Ideally, these sessions should be ‘protected from clinical work’ to maximise attendance. † All midwives and doctors should be encouraged to participate in weekly case review meetings, as this is the best way of reinforcing knowledge. † Self-directed learning should be encouraged. Units should provide learning resources such as books, interactive CD-ROMs or access to websites. Inaction with suspicious or abnormal CTG Inaction is a common feature in many claims. An abnormal CTG is considered to indicate a risk of fetal hypoxia, it is indefensible to take no action and, indeed, it is not acceptable practice. An appropriate action might include a decision to ‘wait and see’ for a limited period while taking remedial actions such as repositioning the woman, stopping oxytocin, using tocolysis (e.g. terbutaline 0.25 mg subcutaneous in the presence of hyperstimulation) or improving placental perfusion by maternal hydration. A fetal scalp blood sample might be obtained if the cervix is sufficiently dilated. Based on the clinical situation, immediate delivery might be the only option. The time of observation and the action taken including a decision to ‘wait and see’ should be recorded in the notes. Initialling the CTG is not enough and if a decision that has been taken is not clearly documented in the notes it will appear in retrospect that the CTG abnormality was simply ignored.
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With persisting FHR abnormalities, the scalp blood samples should be repeated within 30 minutes even if the previous results were normal. Time is of the essence in cases of prolonged FHR bradycardia because hypoxia and acidosis can develop rapidly. In such cases, especially if the bradycardia is due to placental abruption, cord prolapse or scar dehiscence, an immediate caesarean section should be performed, ideally within 15 minutes and certainly no longer than 30 minutes. There is a strong correlation between poor neonatal outcome and a delayed decision to deliver. Experienced paediatric personnel, skilled in neonatal intubation, should attend the delivery if resuscitation is anticipated. The promptness and efficiency of neonatal resuscitation might be critical in determining the subsequent fate of the infant. Unrecognised oxytocin hyperstimulation A common problem in litigation cases is oxytocin-induced hyperstimulation leading to prolonged decelerations, aggravation of existing late or variable decelerations, uterine rupture, fetal hypoxia and brain damage. This situation tends to occur when the monitoring of contractions is inadequate. It can allow excessive uterine activity to continue unrecognised, thus delaying the appropriate response to decrease or discontinue oxytocin. The only effective strategy to prevent claims based on unrecognised oxytocin hyperstimulation is to be meticulous in detecting uterine contractions. Contractions are most conveniently monitored externally with a tocodynamometer.10 Prior to commencing oxytocic agents, the nature of the uterine contraction should be recorded. There should be a clear labour-ward policy for oxytocin regimen. It goes without saying that with excessive uterine activity oxytocin should be stopped or discontinued. Furthermore, oxytocin should be discontinued in the presence of an abnormal FHR pattern and should only be restarted if the FHR becomes normal or if acidosis is excluded by scalp blood sampling. Oxytocin infusion rates in excess of 8 – 12 milliunits/minute can result in significant hyperstimulation; therefore dosage increments should be approached with caution. Oxytocin should be used with caution in the presence of a previous uterine scar because it is more common for such scars to rupture with oxytocin augmentation or induction of labour than during spontaneous labour.11 It is difficult to defend a case of a ruptured uterus successfully when oxytocin was used, unless there is clear evidence that uterine activity was monitored adequately, that it did not show hyperstimulation and that prompt action was taken on clinical suspicion or abnormal FHR findings suggestive of impending scar rupture. Failure to incorporate the clinical picture It must always be borne in mind that the CTG is only an investigation and that monitoring labour using only a single parameter is never sufficient. With any given CTG, the clinical actions and decisions will vary depending on the clinical picture. For instance, an abnormal CTG showing fetal tachycardia with atypical variable or late decelerations and reduced variability at 3 – 4 cm in a primigravid might warrant a caesarean section, whereas at 7– 8 cm it might indicate the need for fetal scalp blood sampling and an instrumental delivery in the second stage, if this can be carried out safely. Other clinical risk factors, such as thick meconium with scanty fluid, intrauterine growth restriction or intrauterine infection, cause a rapid decline in pH with
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an abnormal CTG and warrant early action. When there is abruption, cord prolapse or possible scar rupture, a suboptimal CTG needs immediate intervention because these traces can suddenly change for the worse, resulting in a poor outcome.10 The clinical picture should always have a major influence on the action planned on the face of a disquieting CTG.
RELATED ISSUES Fetal scalp blood sampling All maternity units where CTG is employed should have ready access—24 hours a day—to an accurate microblood gas analyzer. CTG is an imperfect tool and many of the indicators used to identify early hypoxia are non-specific. Thus, if CTG is used as the sole method of intrapartum fetal surveillance, unnecessary operative deliveries will be performed.12 Fetal scalp blood sampling should therefore be performed in the presence of abnormal FHR patterns unless the CTG and/or the clinical picture demand immediate delivery. The correct equipment and optimum positioning of the woman for fetal blood sampling is very important. Once fetal scalp sampling has been done, pressure with a swab to the site of the puncture should stop the bleeding. After the amnioscope has been withdrawn, the mother must be observed to exclude significant fetal haemorrhage from the scalp puncture site. Two fetal blood samples taken at a 30-minute interval might be required to determine the rate of decline in the pH, in the face of persisting FHR abnormalities. If the rate of decline in the pH indicates possible fetal acidosis prior to the anticipated time of birth, then the delivery should be expedited. Immediate delivery is indicated if the pH is less than 7.20.13 The use of bedside fetal lactate measurement (using 5 ml of blood) to better define metabolic acidosis is becoming more popular.14 This will also reduce the number of cases in which the FBS tests are abandoned because of insufficient samples. Umbilical cord artery blood acid–base analysis In the current climate, any mishap in the delivery room has the potential to become a litigation case. For instance, the parents of a baby born with a low Apgar score and who required assisted ventilation might take legal action at a later date if the child develops neurological problems. However, the Apgar score was designed to assess the need and extent of resuscitation needed by a newborn, and a low Apgar score is poor at defining asphyxia; there are many other causes. Obstetric experts involved in litigation cases of birth asphyxia suggest that the Apgar score is a subjective evaluation and might be biased by the attending staff in the delivery room. This view is supported by both the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, who have challenged the use of Apgar score to define birth asphyxia. Various criteria has been set by national colleges and other groups to define the term ‘birth asphyxia’. The following essential and/or additional criteria were recently suggested by a group meeting in Australia.15
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Essential criteria † profound umbilical artery metabolic acidemia (pH , 7.0 and base deficit BD . 12) † early onset of severe or moderate encephalopathy in infants . 34 weeks † cerebral palsy of a spastic quadriplegic or dyskinetic type Additional criteria † † † † †
A sentinel hypoxic event occurring immediately before or during labour. A sudden rapid sustained deterioration in FHR pattern. Apgar scores of , 7 after 5 minutes. Early evidence of multi-organ ischaemic injury. Early evidence of acute cerebral involvement.
A useful way of ruling out the diagnosis of birth asphyxia in a depressed newborn is to analyse the umbilical cord arterial blood gases. This technique is simple, convenient and provides objective assessment of the newborn’s condition at delivery.16 The umbilical cord arterial blood gas result could potentially reduce the risk of litigation and associated expenses by excluding birth asphyxia if cerebral palsy is diagnosed later.17 Many maternity units now routinely determine umbilical cord arterial and venous blood acid – base status on all deliveries.18 However, this approach has a cost implication. If, for reasons of cost, sampling is done on a selective basis, then the cord arterial blood pH and base deficit should be determined in cases where there has been any concern during labour, operative deliveries (especially those for suspected fetal compromise), cases where a fetal scalp blood sample was done, those who had abnormal traces, those with moderate and thick meconium-stained amniotic fluid, who had bleeding in labour, preterm infants, multiple gestations, vaginal breech deliveries and the depressed infant at birth.
CLINICAL RISK MANAGEMENT The ultimate aim of clinical risk management is to improve the standard of patient care. Improvements in the standard of practice and enhancement in patient safety brought about by this process should, in theory, minimise litigation. The process begins with the identification of critical incidents and adverse outcomes, establishing why and where things went wrong (root-cause analysis of events can help distinguish between ‘active failures’ of individual practitioners and ‘latent failures’ within the organisation). Lessons learned from this analysis, and any subsequent recommendations, should be disseminated to all relevant staff to prevent a recurrence.19 The main stimulus for the recent increase in clinical risk management activity seems to be an attempt by health service providers to curb the spiralling cost of obstetric litigation.20 Many maternity units in the UK have now formed Clinical Risk Management (CRM) groups of senior representatives from the various disciplines, hospital management and the legal team. A typical group might consist of a Lead Obstetrician, Clinical Director, Delivery Suite Manager, Clinical Risk Co-ordinator, Paediatrician, Obstetric Anaesthetist and Hospital Litigation Officer. Meeting once a fortnight or once a month, a CRM group will review incidents that have given rise to complications based on agreed list of adverse events that might give rise to litigation. This allows an initial investigation to be carried out as
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soon as possible after an adverse event and for the relevant staff to be asked to produce a statement of their involvement to supplement the existing medical records while the evidence is still fresh in their minds. The process should not focus on questions of attribution and individual staff must not be called before the group, otherwise the clinical staff might feel the process to be punitive and be less inclined to report adverse incidents. The downside is the difficulty with putting any policy action into practice. In-house educational programmes or ‘study days’ can help raise the level of awareness of any recommendations and thus prevent a recurrence. Most importantly, a successful process should engender a sense of ownership among the staff. Another important function of the CRM group is to instigate audit standards of clinical care and adverse outcomes. Audit of low arterial cord pH in newborns, admission to neonatal unit, the need for assisted ventilation and the decision-todelivery interval for emergency caesarean sections for presumed fetal compromise are some of the topics that can be used to identify suboptimal practices and organisational problems that contribute to adverse outcomes even where these do not prompt legal action. Rapid review of adverse incidents, audits and continuing educational programmes are likely to achieve a reduction in litigation by identifying weaknesses and putting remedial processes in place.
CAUSATION AND LIABILITY The crucial first step for successful legal action is to establish causation. The question to consider is whether brain injury is a direct consequence of intrapartum asphyxia. The essential requirements for this are an abnormal CTG, evidence of severe perinatal asphyxia (i.e. arterial cord pH , 7.0), a depressed newborn requiring intensive resuscitation, neonatal neurological sequelae and evidence of multiorgan system dysfunction. If the CTG was normal, or the cause of neonatal encephalopathy remains unclear, then the Paediatric Neurologist should be asked to exclude a host of metabolic, genetic and infectious causes of neurological impairment. An accurate diagnosis of the underlying disorder is ultimately in the child’s best interest. If the history is suggestive of severe perinatal asphyxia then the focus will shift to the question of liability. The medical records will be scrutinised to determine whether the standard of care fell short of acceptable practice and whether appropriate action was taken in the presence of an abnormal CTG. The timing of intervention and the definition of acceptable practice are major areas of disputes. Liability is usually judged on what a reasonably competent practitioner would have done (the Bolam test). According to the Bolam principle: The test is the standard of the ordinary skilled man exercising and professing to have the specialist skill. A man need not possess the highest expert skill to be at risk of being found negligent. If a breach in the standard of care is established then compensation will be awarded.21 The Bolitho principle is increasingly being used, especially in cases in which there is an unresolved dispute among medical experts as to whether liability is due to omission or commission of care by the practitioner. According to the Bolitho principle:
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If it can be demonstrated that the professional opinion is not capable of withstanding logical analysis, the judge is entitled to hold that the body of opinion is not reasonable or responsible.
CONCLUSION The threat of litigation is said to be the obstetrician’s and the midwife’s worst nightmare. The anguish of being involved in litigation can have long-term consequences on the working lives of these practitioners. On the other hand, everyone has sympathy for the parents with a handicapped child, nothing can compensate for the grief and the enormous burden that such a tragedy imposes on the rest of the family. Rapid investigation and prompt discussion of events would allay parental anger. If causation and liability were proven beyond doubt, it would be worthwhile settling these cases out of Court. Unfortunately, obstetric litigation will continue to rise. Nowadays parents expect to give birth to a healthy baby and if the baby is born with neurological deficits parents and their advisors believe that someone is to blame. The CTG is here to stay, despite the ongoing debate about its widespread application. Additional methods of intrapartum fetal monitoring are in early clinical use. However, most of these methods are used in conjunction with the CTG, hence the importance of learning about CTG interpretation. The other monitoring modalities currently in use are discussed elsewhere in this issue. The challenge facing perinatal healthcare professionals is how to achieve optimal maternal and neonatal outcomes without resorting to defensive practice. Structured and compulsory training in CTG interpretation for all midwives and doctors, good practice and good communication, and the use of adjuncts such as FBS for pH and blood gases or lactate, pulse oximetry or fetal ECG waveform analysis will play an important role in reducing adverse events and avoiding litigation. Better education of the public about the limitations of the technology would also help to reduce the gap between expectations and outcomes. Practice points All maternity units should have the following in place: † regular and compulsory training in the interpretation of CTG for all staff involved in intrapartum care † guidelines on CTG interpretation and appropriate management options for abnormal CTG in spontaneous, augmented and induced labour † an effective and reliable way of record keeping and CTG storage. Electronic archiving systems can help solve this problem † ready access to fetal scalp blood sampling or measured introduction of adjunctive methods of fetal surveillance † measurement of umbilical cord artery blood pH in deliveries where there was concern for the fetus during labour, operative/difficult deliveries or when the neonate’s condition at delivery is suboptimal † a mechanism for the rapid review of adverse events and dissemination of recommendations † regular audit of adverse outcomes
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Research agenda † evaluate the impact of CTG education on improvement in clinical outcome † improve computerised interpretation of intrapartum CTGs to increase the sensitivity and specificity (e.g. evaluation of short-term variability) † assess neonatal outcome related to incident/insult-to-delivery interval compared with decision-to-delivery interval † evaluate the possible mechanisms of fetal neurological injury
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