Neonatal resuscitation: Current issues

The following guidelines are intended for practitioners responsible for resuscitating neonates. They apply primarily to neonates undergoing transition from intrauterine to extrauterine life. The updated guidelines on Neonatal Resuscitation have assimilated the latest evidence in neonatal resuscitation. Important changes with regard to the old guidelines and recommendations for daily practice are provided. Current controversial issues concerning neonatal resuscitation are reviewed and argued in the context of the ILCOR 2005 consensus.


Neonatal resuscitation: Current issues Indu A Chadha
Department of Anaesthesiology, B J Medical College, Ahmedabad -38 0016, India

INTRODUCTION
Neonatal Asphyxia accounts for 20.9% of neonatal deaths.] The goals of neonatal resuscitation are to prevent the morbidity and mortality associated with hypoxicischaemic tissue (brain, heart, kidney) injury and also to re-establish adequate spontaneous respiration and cardiac output. [2,3]idelines for neonatal resuscitation have been issued by the American Heart Association and the American Academy of Paediatrics.The guidelines are helpful in remembering the sequence for resuscitation.Failure to follow the guidelines has resulted in bad outcomes. [1,2]rapid assessment of newly born infants who do not require resuscitation can generally be identified by the following four characteristics: 1. Was the infant born after a full-term gestation?2. Is the amniotic fluid clear of meconium and evidence of infection?3. Is the infant breathing or crying?4. Does the infant have good muscle tone?
If the answer to all four of these questions is 'yes,' the infant does not need resuscitation and should not be separated from the mother.The infant can be dried, placed directly on the mother's chest and covered with dry linen, to maintain temperature.Observation of breathing, activity and colour should be ongoing.
If the answer to any of these assessment questions is 'no,' there is a general agreement that the infant should receive one or more of the following four categories of action in sequence: 1.Initial steps in stabilisation (provide warmth, position, clear airway, dry, stimulate, re-position) 2. Ventilation 3. Chest compressions 4. Administration of epinephrine and / or volume expansion The decision to progress from one category to the next is determined by the simultaneous assessment of three vital signs: respiration, heart rate and colour.Approximately 30 seconds is allotted to complete each step, re-evaluate and decide whether to progress to the next step [1][2][3][4] [Figure 1].
position the head in a 'sniffing' position to open the airway, clear the airway with a bulb syringe or suction catheter, dry the infant and stimulate breathing.Evaluation of the neonate for respiration, heart rate and colour at every 30-second interval must be done [1][2][3][4][5][6][7] [Figure 1].The above guidelines are to be followed during every delivery of a newborn.
Although the Apgar score is a simple useful guide to neonatal well-being and resuscitation, it is only a guide.It is useful to convey the information about a newborn's overall status and response to resuscitation at the time points, during resuscitation.The one minute score correlates well with acidosis and survival.[9][10][11] In every delivery room, an area should be allotted for neonatal resuscitation, with all the necessary equipment and drugs stored nearby [Table 1].During every delivery there should be at least one person whose primary responsibility is the new born.This person must be capable of initiating resuscitation, including administration of positive-pressure ventilation and chest compression. [1,3] high-risk births, the majority of newborns requiring resuscitation can be identified before birth.If need for resuscitation is anticipated, additional skilled personnel should be recruited and the necessary equipment prepared.3] If a pre-term delivery (< 37 weeks of gestation) is expected, special preparations will be required.

SPECIAL SITUATIONS
Conditions like Choanal atresia, pharyngeal airway malformations, laryngeal web, pneumothorax, plural effusion and Diaphramatic hernia should be looked for.][4] POST-RESUSCITATION CARE Infants who require resuscitation are at risk of deterioration after their vital signs have returned to normal.][4]

GUIDELINES FOR wITHHOLDING AND DISCONTINUING RESUSCITATION
Morbidity and mortality for newborns vary according to the region and availability of resources. [2] withholding resuscitation For conditions associated with high mortality and poor outcome, withholding resuscitative efforts may be considered, particularly when there has been parental agreement.[2,11,12] A consistent and coordinated approach to individual cases by the obstetric and neonatal teams and the parents is an important goal.[2,10,12] Non-initiation of resuscitation and discontinuation of life-sustaining treatment during or after resuscitation are ethically equivalent, and clinicians should not hesitate to withdraw support with no functional survival.The following guidelines must be interpreted: [2,11] 1.When gestation, birth weight or congenital anomalies are associated with certain early death and unacceptably high morbidity, resuscitation is not indicated, for example, extreme prematurity (gestational age < 23 weeks or birth weight < 400 g), anencephaly or chromosomal abnormalities, such as trisomy 13. 2. In conditions with a high rate of survival and acceptable morbidity, resuscitation is nearly always indicated, for example, infant with gestational age 25 weeks and infant with congenital malformations.3. In conditons associated with uncertain prognosis, wherein survival is borderline, the morbidity rate is high and the anticipated burden to the child is high, parental desires concerning initiation of resuscitation should be supported.

Discontinuing resuscitative efforts
Infants without signs of life (no heart beat and no respiratory effort) after 10 minutes of resuscitation show either a high mortality or severe neuro-developmental 3] CURRENT ISSUES

Temperature control
For the full-term newborn both standard thermal care (removing wet blankets, prompt drying, warming pads, wrapping the infant in a warm blanket, placing the infant skin-to-skin with the mother and covering both with a blanket) and placing the dried infant under a radiant heater are effective in maintaining normal body temperature. [14,15][18][19] Only the is dried and covered with a cap.All resuscitation procedures, including intubation, chest compressions, and insertion of (central) lines, can be performed with the plastic cover in place.Currently, there is no evidence that this procedure improves mortality or the long-term outcome.Monitoring of body temperature should be considered, especially when resuscitation is prolonged, to avoid the small risk of inducing hyperthermia. [17,19,20][23][24] Hyperthermia should be avoided.The goal is to achieve normothermia and avoid iatrogenic hyperthermia.
Clearing the airway of meconium Aspiration of meconium before delivery, during birth or during resuscitation can cause severe meconium aspiration pneumonia (MAS) in 2 -9% of the newborn infants. [25]One obstetrical technique, to try to decrease aspiration has been to suction the meconium from the infant's airway after delivery of the head, but before delivery of the shoulders (intrapartum suctioning).
Studies suggest that intrapartum suctioning may be effective for decreasing the risk of the aspiration syndrome, [26][27][28] but evidence from a large trial did not show such an effect. [29]Therefore, current recommendations no longer advise routine intrapartum oropharyngeal and nasopharyngeal suctioning.In the case of meconium-stained amniotic fluid and a non-vigorous newborn, endotracheal suction by brief intubation or suction under direct vision is advised.
If the infant is vigorous, endotracheal suction is not recommended, because it may cause harm and does not improve the outcome. [30]ministration of oxygen A normal newly born infant achieves and maintains pink mucous membranes without administration of supplementary oxygen. [31,32]33] Healthy term newborns reach pre-ductal oxygen saturations, between 79 and 91%, 5 minutes after birth, [34] and it may take > 10 minutes to achieve a pre-ductal oxygen saturation of > 95% and nearly one hour to achieve post-ductal saturation of > 95%. [35,36]wborns delivered by caesarean section and preterms reach average pre-ductal oxygen saturations of 90%, two minutes later than the healthy term newborns. [31,32]here is concern about the potential adverse effects of 100% oxygen on the respiratory physiology, cerebral circulation, and tissue damage from oxygenfree radicals.Conversely, there is also concern about tissue damage from oxygen deprivation during and after asphyxia.[39][40][41][42] Study of preterm infants (< 33 weeks of gestation) exposed to 80% oxygen found lower cerebral blood flow when compared with those stabilized using 21% oxygen. [43]Meta-analysis studies showed a reduction in mortality rate and no harm in infants resuscitated in room air than with 100% oxygen. [44,45]pplementary oxygen is recommended whenever positive-pressure ventilation is indicated for resuscitation; free-flow oxygen should be administered to infants who are breathing, but have central cyanosis.
The standard approach for resuscitation is to use100% oxygen.Some clinicians may begin resuscitation with an oxygen concentration of less than 100% and some may start with room air.Both these practices during resuscitation of neonates are reasonable.If the clinician begins resuscitation with room air, supplementary oxygen must be available to use if there is no appreciable improvement within 90 seconds of the birth.In situations where supplementary oxygen is not readily available, positive-pressure ventilation should be administered with room air.Administration of a variable concentration of oxygen guided by pulse oximetry may improve the ability to achieve normoxia more quickly.

Initial breaths and assisted ventilation
48][49][50] The optimum pressure, inflation time, and flow rate required to establish an effective functional residual capacity have not been determined.
Inflation breaths are used in newborn resuscitation, to facilitate the aeration of the fluid-filled lungs, by applying a higher airway pressure for a prolonged period of time.
When a pressure of 30 cm H 2 O is applied for a duration of five seconds, a higher lung volume is achieved than in the conventional one-second inflations. [47]One trial in preterm newborns has shown that sustained initial inflations through a nasopharyngeal tube, followed by nasal Continuous Positive airway pressure (CPAP), reduces the need for intubation. [47]Although the evidence is based on a few studies, inflation breaths may have a positive effect on postnatal for newborns in need of resuscitation.
][51] Assisted ventilation rates of 40 to 60 breaths per minute are commonly used, but the relative efficacy of various rates has not been investigated.
The primary measure of adequate initial ventilation is the prompt improvement in heart rate.Chest wall movement should be assessed if the heart rate does not improve.If inflation pressure is being monitored, an initial inflation pressure of 20 cm H 2 O may be effective, but 30 to 40 cm H 2 O may be required in some term infants without spontaneous ventilation.If pressure is not monitored, the minimum inflation required to achieve an increase in heart rate should be used. [52]There is insufficient evidence to recommend an optimum inflation time.In summary, assisted ventilation should be delivered at a rate of 40 to 60 breaths per minute, to promptly achieve or maintain a heart rate >100 bpm.The optimum pressure, inflation time and flow required to establish an effective Functional Residual Capacity (FRC) has not yet been determined.

Devices
4] A T-piece is a valved mechanical device, designed to control flow and limit pressure.The pop-off valves of self-inflating bags are flow-dependent, and the pressures generated may exceed the value. [55]Target inflation pressures and long inspiratory times are more consistently achieved with a T-piece, rather than with bags, although the clinical implications are not clear. [56]o provide the desired pressure, healthcare providers need more training in the use of flow-inflating bags than with self-inflating bags. [57]ryngeal mask airways (LMAs) that fit over the laryngeal inlet have been shown to be effective for ventilating newly born near-term and full-term infants. [58,59]There are limited data on the use of these devices in small preterm infants. [60,61]The use of the LMA can provide effective ventilation in a time frame consistent with the current resuscitation guidelines, [59,61,62] although the infants studied were not being resuscitated.A controlled trial found no clinically significant difference between the use of the LMA and endotracheal intubation when the bag-mask ventilation was unsuccessful. [58][65] There is insufficient evidence to support the routine use of the LMA as the primary airway device during neonatal resuscitation, in the setting of meconium-stained amniotic fluid, when chest compressions are required, in very low birth weight infants, or for delivery of emergency intra-tracheal medications.In the case of non-successful mask ventilation, where endotracheal intubation is not possible or problematic, a laryngeal mask should be considered as a good alternative. [66,67]dotracheal tube placement Endotracheal intubation may be indicated at several points during neonatal resuscitation: a) When tracheal suctioning for meconium is required b) If bag-mask ventilation is ineffective or prolonged c) When chest compressions are performed d) When endotracheal administration of medications is desired For special resuscitation circumstances, such as congenital diaphragmatic hernia or extremely low birth weight (< 1000 g), the timing of endotracheal intubation may depend on the skill and experience of the providers.

After endotracheal intubation and administration
68] Exhaled CO 2 detection is effective for confirmation of endotracheal tube placement in infants and very low birth weight infants. [69,70]Exhaled CO 2 detection is useful as a quick confirmation of the accurate position of the endotracheal tube, especially when clinical judgement is uncertain. [70,71][70][71] Other clinical indicators of correct endotracheal tube placement are visual assessment during intubation, condensed humidified gas during exhalation, the presence or absence of chest movement and the confirmatory method after intubation, if the heart rate remains low and is not rising.These methods have to be systematically evaluated in neonates.

Chest compressions
Chest compressions are indicated for a heart rate that is < 60 bpm despite adequate ventilation with supplementary oxygen for 30 seconds.As ventilation is the most effective action in neonatal resuscitation and because chest compressions are likely to compete with effective ventilation, rescuers should ensure that assisted ventilation is being delivered optimally before starting chest compressions.Compressions should be delivered on the lower third of the sternum, [72,73] to a depth of approximately one-third of the anteriorposterior diameter of the chest.
Two techniques have been described [Figure 2]: a) Compression with two thumbs with fingers encircling the chest and supporting the back. [72,73]) Compression with two fingers with a second hand supporting the back.
The two-thumbs-encircling hands technique may generate higher peak systolic and coronary perfusion pressure than the two-finger technique. [74,75]The twothumb-encircling hands technique is recommended in newly born infants.However, the two-finger technique may be preferable when access to the umbilicus is required during insertion of an umbilical catheter.
Compressions and ventilations should be coordinated to avoid simultaneous delivery.The chest should be permitted to fully re-expand during relaxation, but the rescuer's thumbs should not leave the chest.There should be a 3:1 ratio of compressions to ventilations with 90 compressions and 30 breaths to achieve120 events per minute, to maximize ventilation at an achievable rate. [76]Thus, each event will be allotted approximately second.However, chest compressions are only effective if the lungs have first been successfully aerated, making the quality of the breaths and compressions more important than the rate.

Medications
Drugs are rarely indicated in resuscitation of the newly born infant. [77,78]Bradycardia is usually because of inadequate lung inflation or profound hypoxemia, and establishing adequate ventilation is the most important step to correct it. [75]However, if the heart rate remains < 60 bpm despite adequate ventilation with 100% oxygen and chest compressions, administration of epinephrine or volume expansion, or both, may be indicated.Rarely are buffers, a narcotic antagonist or vasopressors useful after resuscitation.

Epinephrine
Past guidelines recommended that initial doses of epinephrine be given through an endotracheal tube because the dose can be administered more quickly than through the intravenous route.Animal studies showed a positive effect of endotracheal epinephrine, using higher doses than are currently recommended. [79,80]83] Animal [82][83][84] and paediatric [84,85] studies show exaggerated hypertension, decreased myocardial function and worse neurologic function after administration of higher doses (0.1 mg/kg) via IV.Therefore, IV administration of 0.01 to 0.03 mg/kg per dose is the preferred route, because the intravenous route in neonates can easily be achieved by inserting an umbilical venous catheter.While access is being obtained, a higher dose (0.1 mg/kg) through the endotracheal tube may be considered, but the safety and efficacy of this practice have not been evaluated.The concentration of epinephrine for either route should be 1:10000 (0.1 mg/ml).[85][86] In addition, high intravenous dosages may increase the risk for intra-ventricular haemorrhage in preterm infants.Therefore, 0.01 -0.03 mg/kg epinephrine is recommended via the intravenous route (via umbilical vein).The dosage can be repeated every one to three minutes.

Volume expansion
Volume expansion must be considered when blood loss is suspected or the infant appears to be in shock (pale skin, poor perfusion, weak pulse) and not responding to other resuscitative measures.An isotonic crystalloid rather than albumin is the solution of choice for volume expansion in the delivery room [87][88][89] The recommended dose is 10 ml/kg of normal saline, which can be repeated.In premature infants, giving volume expanders too rapidly must be avoided, because rapid infusions of large volumes can cause intra-ventricular haemorrhage.Emergency volume expansion may be accomplished with an isotonic crystalloid solution or O-negative red blood cells.[89] Intraosseous access can serve as an alternative route for medications / volume expansion.

Naloxone
Naloxone is not a drug of choice as a part of initial resuscitative efforts in the delivery room for newborns with respiratory depression.If administration of naloxone is considered, heart rate and colour must first be restored by supporting ventilation.The preferred recommended route is IV or intra-muscular administration of naloxone.The recommended dose is 0.1 mg/kg, but no studies have examined the efficacy of this dose in newborns.Naloxone given to an infant born to an opioid-addicted mother has been associated with seizures. [90]Therefore, naloxone must be avoided in infants of mothers with opioid abuse.Naloxone is indicated in the infant for reversal of respiratory depression, secondary to maternal opioids, given four hours before delivery.Naloxone has a shorter half-life than the original maternal opioid.Therefore, the neonate must be monitored closely for recurrent apnoea or hypoventilation, and subsequent doses of naloxone may be required.

Glucose
Low blood glucose has been associated with an adverse neurologic outcome in a neonatal animal model of asphyxia and resuscitation. [91]Neonatal animals that were hypoglycemic at the time of an anoxic or hypoxic-ischaemic insult had larger areas of cerebral infarction or decreased survival, or both, when compared with the controls.One clinical study showed an association between hypoglycaemia and a poor neurologic outcome in perinatal asphyxia. [92]e blood glucose concentration associated with the least brain injury after asphyxia and resuscitation cannot be defined based on the available evidence.Infants requiring resuscitation should be monitored and treated to maintain a normal glucose level; 50% Dextrose in a dose of 0.5 ml/kg may be given to correct hypoglycaemia.

Sodium bicarbonate
Use of sodium bicarbonate during resuscitation is controversial.It may be helpful to correct metabolic acidosis after a prolonged period of resuscitation. [81]owever, it is harmful, particularly if given too early, as it mixes with acid and forms carbon dioxide.The lungs must be adequately ventilated to remove the carbon dioxide.The dose is 1 -2 mEq / Kg / dose given as 4.2% solution (0.5 mEq/ml) at the rate of 1mEq / Kg / min.

Induced hypothermia
Studies are conflicting.One multicenter trial did not show a difference in the number of survivors with severe disabilities when head cooling was used. [93][96] A rapid increase in body temperature could cause hypotension. [97]Cooling to a core temperature of < 33°C may cause arrhythmia, bleeding, thrombosis and sepsis, but studies have not reported these complications with modest hypothermia. [95,96,98]Avoidance of hyperthermia is particularly important in infants who may have had a hypoxic-ischaemic event.
There is insufficient data to recommend the routine use of modest systemic or selective cerebral hypothermia after resuscitation of infants with suspected asphyxia.
Chadha: Neonatal resuscitation: Current issues Further clinical trials are needed to determine which infants benefit most and which method of cooling is most effective.

CONCLUSION
Neonatal resuscitation contributes to a better care of newly born infants.Many important issues concerning neonatal resuscitation, have to be answered in the future, such as the effect of endotracheal suction in a meconium-stained, non-vigorous newborn, the outcome of preterm infants treated with occlusive plastic wrapping, the effect of inflation breaths with positive end-expiratory pressure on postnatal adaptation for newborns, the percentage and timing of additional oxygen in newborns not responding initially, the use of continuous positive airway pressure during neonatal resuscitation, the most efficacious intravenous dose of epinephrine in newborns with an asystole and the outcome of infants treated with hypothermia.In addition, implementation and training of the new guidelines in Neonatal Life Support Programmes will further contribute to the improvement in the care of newborn infants.
may be considered at several steps.

Figure 2 :
Figure 2: Two methods of chest compression (Neonatal Resuscitation Guidelines, Circulation, 2005) catheter.If bradycardia occurs during suctioning then stop suctioning and re-evaluate the heart rate.
e) If the newborn is not breathing and remains apnoeic or gasping, has a heart rate of < 100 bpm or appears blue, the next step is to assist the neonate's breathing by positive pressure ventilation, and if he is cyanotic supplemental oxygen is to be given.

Table 1 : Neonatal resuscitation supplies and equipment 1. Suction equipment 4. Medication
Tape half or three-fourth inches Cardiac monitor and electrodes or pulse oximeter and probe (optional for delivery room) Oropharyngeal airway (0, 00, and 000 sizes or 30, 40, 50 mm lengths) 3. Intubation equipment 6.For very pre-term babies Laryngoscope with straight blades, No.0 (preterm) and No.1 (term) Extra bulbs and batteries for laryngoscope Endotracheal tubes 2.5,3.0,3.5,4.0-mminternal diameter (ID) Stylet (optional) Scissors Tape or securing device for ET tube Alcohol sponges CO 2 detector or capnograph Laryngeal mask airway (optional) Compressed air source O 2 blender to mix O 2 and compressed air Pulse oximeter and probe Re-closeable, food-graded plastic bag (1-gallon size) or plastic wrap Chemically activated warming pad Transport incubator to maintain baby's temperature during its move to the nursery