[back] Cord Clamping

PAPERS:
Analysis of cord blood gas at delivery: questionnaire study of practice in the United Kingdom
Jason Waugh, Anthony Johnson, and Andrew Farkas
BMJ 2001; 323: 727 [Full text]
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Rapid responses published:

[Read Rapid response] hat about cord blood lactate?
K N P Mickleson   (30 September 2001)
[Read Rapid response] Avoiding unmeritorious legal claims
Anthony Barton   (5 October 2001)
[Read Rapid response] It's just one blood gas result
Michael Hewson   (7 November 2001)
[Read Rapid response] Cerebral Palsy and Cord Blood Gases
George M Morley, MB ChB, none   (6 May 2002)


 
hat about cord blood lactate? 30 September 2001
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K N P Mickleson
Auckland

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Re: hat about cord blood lactate?
 

Email K N P Mickleson:
knpmsain@xtra.co.nz

 

Having been involved in many deliveries in a large unit I have often wondered why arterial cord blood lactate, an accurate measurement, has seemed never to have become established amongst Obstetricians.


 
Avoiding unmeritorious legal claims 5 October 2001
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Anthony Barton,
Solicitor and Medical Practitioner

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Re: Avoiding unmeritorious legal claims
 

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acb@cmck.com

 

Waugh and others state that "recording cord blood gases is important if cerebral palsy is later diagnosed". This procedure is of forensic as well as clinical importance; its application is retrospective. Normal cord blood gases represent evidence of absence of hypoxia at the time of birth.

Most litigation concerning cerebral palsy is legally aided. Although only a small proportion of cerebral palsy cases are due to intrapartum events, claimant lawyers argue that every case of cerebral palsy should be investigated. Funding is granted on the advice of the applicant's lawyer: most legally aided cases fail. Lawyers are often not deterred by absence of evidence, especially where cases are state funded. Evidence of absence may prove a more effective deterrent. Lawyers readily exploit the emotive argument about compensation for brain damaged babies as they (lawyers) are the main beneficiaries of legal action.

A process which can limit inappropriate legal action is to be welcomed.


 
It's just one blood gas result 7 November 2001
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Michael Hewson,
Neonatal Paediatrician
Wellington Hospital, New Zealand

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Re: It's just one blood gas result
 

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michael.hewson@ccdhb.org.nz

 

The authors suggest that routine cord gas determination will hold the line against unwarranted claims for compensation. Probably a more useful, cost-effective, and universally available discriminator would be the presence or absence of neonatal encephalopathy: no encephalopathy - no intrapartum asphyxia.

In the presence of encephalopathy, cord pH > 7.0 has never been shown to be of adequate specificity to exclude a diagnosis of intrapartum asphyxia.

Cord blood gases can be helpful, but they don't replace a full review of the history, clinical findings, and all investigations including neuro- imaging.

We (and our patients) probably still need lawyers.


 
Cerebral Palsy and Cord Blood Gases 6 May 2002
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George M Morley, MB ChB,
retired obstetrician
P.O. Box 181, Northport, MI 496770 USA,
none

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Re: Cerebral Palsy and Cord Blood Gases
 

Email George M Morley, MB ChB, et al.:
obgmmorley@aol.com

 

It is with great regret that I find that obstetricians in my native land have been medico-legally terrorized into the very same irrational and counter-productive procedures as American obstetricians. The analysis of cord blood gases has absolutely no bearing on the therapy or resuscitaion of a newborn. It is pure medico-legal evidence for doctor/hospital protection, taken in the forlorn hope that normal readings might reduce a settlement by a million pounds or dollars. Rational medical care requires comprehension of physiology, then the maintenance or the restoration of the physiological state - health; the guiding principle to avoid settlements is "First, do no harm!"

In 1969, Windle [1] produced (caused) spastic paralysis in monkeys by interrupting placental function at birth and preventing pulmonary respiration for measured periods. About 5 or 6 minutes of asphyxia was enough to produce permanent neurological damage that was confirmed by defined brain lesions at autopsy. In monkeys that recovered from (adapted to) minor damage, memory defects were noted - these monkeys could not remember for one minute into which canister food was placed; normal monkeys got it right almost every time. The asphyxiated monkeys had, in effect, attention deficit disorder. Brain damage in these monkeys occurred AFTER they were born.

Primates are characterized by a very large, oxygen dependent brain, and at normal, physiological birth, placental oxygenation of the brain (signified by cord pulsation) continues until pulmonary oxygenation is well established; establishment of pulmonary respiration entails transfusion of a large amount of placental blood into the neonate to initiate and maintain the pulmonary circulation. These physiological events are firmly programmed into the neonates reflexes by its genetic code to prevent hypoxic brain damage and to support optimal survival. After the newborn is breathing and pink, the cord vessels close physiologically. Without these reflexive mechanisms, the primate order (and Man) would be extinct. The cord clamp is not a part of human anatomy or human physiology.

The procedure for obtaining cord blood gases at birth is to amputate the child's placenta immediately and save a cord section containing blood. This results in immediate asphyxia - loss of placental oxygenation and loss of placental transfusion that establishes pulmonary oxygenation. If the neonatologist cannot adequately restore the child's blood volume and effect ventilation with pulmonary circulation within five minutes, the result of immediate clamping will be exactly the same as Windle produced in his monkeys - spastic paralysis. Even if adequate oxygenation from ventilation is achieved, the child is still extremely hypovolemic with deficient perfusion of other life support organ-systems.

The previous paragraph applies to a normal newborn. In fetal distress due to cord compression,(tight cord around the neck is the most common cause), compression acts a a venous tourniquet and the placenta becomes engorged with fetal blood volume; the child is born ashen white. Cord blood analysis (immediate cord clamping) at this time may well cause fatality. [2] If the child survives immediate clamping, it is extremely hypovolemic, hypoxic and ischemic, and very prone to develop hypoxic, ischemic encephalopathy in the NICU.

Such newborns seldom convulse at birth; if the cord is left intact and the compression is relieved with the child placed well below the level of the placenta, massive transfusion of oxygenated placental blood and continued placental circulation (oxygenation) will often turn the child purple, then pink. Brain damage incurred in utero will never be reversed, but additional brain damage or primary brain damage should be prevented. A newborn that receives a 50% boost in blood volume of oxygenated placental blood is unlikely to develop hypoxic, ischemic lesions; a hypoxic, hypovolemic newborn that loses its placental life support system (and its blood volume) at the moment of birth is almost certain to suffer brain damage.

Therefore, immediate cord clamping is a probable cause of the brain injury that the obstetrician is hoping to avoid; it is not rational medical care. If a cord pH is reported normal and the child has brain damage, the cord pH proceure is the probable cause of the brain damage. If a cord pH is abnormal and the child is brain damaged, the cord pH procedure probably caused or augmented the brain damage. Immediate cord clamping to obtain blood gases or a pH is not a rational medico-legal act.

Thus the presence of a cord pH, regardless of it being normal or otherwise, in the records of a child with birth brain injury is evidence that strongly indicates iatrogenic cause. If a cord pH is ever deemed necessary at birth, a scalp pH should suffice, or a very fine needle inserted into a pulsating cord vessel will provide the blood sample without destruction of the child's only functioning life support system.

The Ethics and Practice Committees of the American College of Obstetricians and Gynecologists over the past two years have been unable to answer the above critique of immediate cord clamping as advocated in their Practice Bulletin 138; however, they have withdrawn Educational Bulletin 216 from publication. One hopes that the Royal College Committee Members of the profession are not too medico-legally petrified to rescue their British colleagues.

TO AVOID BIRTH ASPHYXIA AND ITS RESULTANT BRAIN INJURY, ONE SHOULD NOT ASPHYXIATE THE CHILD WITH A CORD CLAMP. Further rational information regarding cord clamping is available at:

www.cordclamping.com

G. M. Morley, MB ChB (Edinburgh 1957) FACOG

References:

1. Windle,W. Brain Damage by Asphyxia at Birth. Scientific American. 1969 Oct; 221(4):76-84

2. Peltonen, T. Placental Transfusio: Advantage - Disadvantage. Eur J Pediatr.1981; 137:141-146

 


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