the baby with a best preductal pO2 <70 mmHg, or a persistent respiratory or metabolic acidosis despite 3-6 hours of expert effort to optimise ventilatory and circulatory support has a poor prognosis</p/><70 mmHg, or a persistent respiratory or metabolic acidosis despite 3-6 hours of expert effort to optimise ventilatory and circulatory support has a poor prognosis
Congenital diaphragmatic hernia is a serious congenital abnormality associated with
15 - 25 cases occur each year in Victoria corresponding to an incidence of approximately 1:3000.
In the early 1990's few were prenatally detected. With the virtual universal occurrence of mid trimester ultrasound examination for fetal abnormality more than 85% of cases are now prenatally detected.
The survival rate for all cases diagnosed is approximately 50-60%.
If a coexistent significant abnormality is present survival is <10%. This illustrates the importance of thorough evaluation, from the time of suspected fetal diagnosis, by a multidisciplinary team familiar with all aspects of the diagnosis and management of CDH.</p/><10%. This illustrates the importance of thorough evaluation, from the time of suspected fetal diagnosis, by a multidisciplinary team familiar with all aspects of the diagnosis and management of CDH
Reported survival for live born infants ranges from 50-90%. The international CDH Study Group database with over 1600 patients reports an overall survival of 66%. The experience for babies managed at RCH, Melbourne shows the survival for babies with isolated lesions to be 75% based on more than 200 infants. The difference in survival for all cases versus liveborns reflects the high rate of termination of pregnancy (TOP) where other anomalies are detected, a lower rate of TOP where an isolated lesion is present, as well as a relatively low incidence of stillbirth.
- establish an accurate description of the abnormalities present
- specify ultrasound features relevant to CDH using a standard form
- degree of mediastinal shift
- liver/stomach position
- lung:head ratio
- liquor volume
- fetal echocardiogram performed by a Paediatric cardiologist, if associated congenital heart disease suspected
- establish a fetal karyotype, if informed parental consent given
- provide informed and supportive counselling for the family including a written summary of any discussion with the parents. This summary should include a description of the abnormalities and most likely diagnoses, management options available, and possible outcomes
- referral to a Paediatric Thoracic Surgeon if not previously arranged
- regular general obstetric surveillance
- repeat Ultrasounds at 24, 30 and 34 weeks to assess fetal growth and features of the CDH as defined above
- prenatal steroid therapy - recommended according to usual indications. Clinical trials are under consideration for use at mature gestations
- fetal operative intervention (tracheal ligation) is an unproven therapy. It is not available in Australia and is not recommended outside of clinical trials (currently in progress overseas)
- to achieve a normal vaginal delivery following spontaneous onset of labour at term
Women who live more than 1 hour from the perinatal centre are encouraged to move to Melbourne at 35-36 weeks gestation. For pragmatic reasons induction of labour at 38-39 weeks is offered to these women.
Caesarean section without labour is not recommended unless there is a clear medical indication.
If unexpected delivery occurs in a Level II nursery, resuscitation must be undertaken and supervised by the most experienced clinician available.
Resuscitation will be individualised according to the condition of the baby and the response to initial steps in resuscitation.
Ventilation using a bag and mask should be minimised.
If endotracheal intubation is required make sure the tube is not inserted too far.
Positive pressure ventilation should be accompanied by inspiratory pressure or volume monitoring, when available.
IPPV, if required, should be provided by a mechanical ventilator at the earliest opportunity.
A large bore nasogastric tube (Ryles tube 10F) should be passed once the baby has been stabilised in the delivery room.
Physical contact with the parents should be facilitated before transfer.
Preductal saturation monitoring should be undertaken during any transfers. Saturations in the 70's and 80's are satisfactory provided sufficient ventilatory support is provided to ensure adequate tidal volume. This is the most difficult situation to get right and in the absence of portable volume monitors a highly experienced clinician must be supervising this period.
Stabilisation - immediate priorities
- achieve acceptable gas exchange
- saturations > 75%
- pCO2 at a level that allows the pH to be > 7.20 while minimising the chances of inducing lung injury or air leak.
- monitor preductal saturations
- apply a transcutaneous pCO2 monitor
- consult with NETS and level 3 centre
Updated 20 February 2012
Units reporting very high survival concentrate on minimising lung injury especially in the initial hours after birth and rarely exceed PIP of 25.
If available use a synchronised mode of ventilation
- establish venous access - if the baby's condition is poor and the circulation compromised rapidly place a UV catheter
- measure blood pressure and assess the circulation to determine the need for volume support
- obtain a chest X Ray
- if the baby's condition remains poor obtain a blood gas by the most expedient route (arterial stab) and adjust support accordingly
- arterial access
- if urgent - cannulate the UA
- if non urgent then either the procedure can be deferred until the baby has been transferred, or a right radial (i.e. preductal) line sited
- do not waste time (and arteries) if the first attempt is unsuccessful
- sedate and muscle relax the baby who remains in poor condition despite attempts at optimising ventilation. In particular muscle relaxants should be considered if the baby requires high pressure IPPV (e.g. a mean airway pressure of > 14)
- surfactant administration (survanta, one ampoule) is optional. Some babies with CDH tolerate this procedure very poorly
The baby with a best preductal pO2 <70 mmHg, or a persistent respiratory or metabolic acidosis despite 3-6 hours of attempting to optimise ventilatory and circulatory support has a very poor prognosis.</p/><70 mmHg, or a persistent respiratory or metabolic acidosis despite 3-6 hours of attempting to optimise ventilatory and circulatory support has a very poor prognosis
- requires a team of neonatologists, paediatric surgeons and paediatric intensivists
- continuous monitoring of transcutaneous pCO2, tidal and minute volumes
- the lowest FiO2 that results in a preductal saturation > 85% is maintained, especially in the initial hours of care. Permissive hypercarbia is strongly advocated
- preductal arterial access is desirable if the infant's condition is marginal
- assessment for dysmorphism - including echocardiography, renal and cranial sonography, a karyotype should be considered
- an ongoing metabolic acidosis requiring repeated large doses of base suggests myocardial ischaemia, sepsis or strangulated bowel
- the principles of management and escalation of therapy include
- use of muscle relaxants and sedatives
- synchronised ventilation (SIMV or A/C) with tidal/minute volume monitoring
- HFOV +/- Inhaled nitric oxide if the baby has unsatisfactory gas exchange after a reasonable trial of conventional ventilation, or there is an ongoing need for high ventilatory pressures or FiO2
- jet ventilation if there is overt gas trapping or air leak
- ECMO - less than 10% of babies need this
- surgery - after ventilatory and circulatory support weaned to satisfactory levels (e.g. FiO2 < 0.4 and mean airway pressure < 14)
- discharge to a level II unit considered after
- full enteral nutrition established for at least one week
- respiratory status indicates significant reserve
- audiology - arranged prior to discharge if possible
- long term follow up required