Neonatal perioperative resuscitation (NePOR) protocol-An update

Abstract

Unexpected cardiac arrest in the perioperative period is a devastating complication. Owing to immaturity of organ systems, and presence of congenital malformations, morbidity and mortality are higher in neonates. There is abundant literature about early recognition and management of perioperative adverse events in children, but similar data and guidelines for surgical neonates is lacking. The current neonatal resuscitation guidelines cater to a newborn requiring resuscitation at the time of birth in the delivery room. The concerns in a newborn undergoing transition from intrauterine to extra uterine life is significantly different from a neonate undergoing surgery. This review highlights the causes and factors responsible for peri-arrest situations in neonates in the perioperative period, suggests preoperative surveillance for prevention of these conditions, and finally presents the resuscitation protocol of the surgical neonate. All these are comprehensively proposed as Neonatal Peri-operative Resuscitation (NePOR) protocol.

Introduction

Unexpected cardiac arrest in the perioperative period is a devastating complication. Few pediatric series reflect an increased incidence of anesthesia related deaths in children (1.4–1.6/10,000 anesthetics)[¹²³] and a still higher incidence in neonates (177/10,000).[⁴]

The current neonatal resuscitation guidelines cater to a newborn requiring resuscitation at the time of birth in the delivery room.[⁵] The concerns in a newborn undergoing transition from intrauterine to extra uterine life are significantly different from the neonate undergoing surgery. A surgical neonate requires a highly skilled resuscitative care in view of immaturity of organ systems, presence of congenital defects, low birth weight and also because of organ dysfunction due to the surgical pathology.

Most of these surgical procedures are urgencies rather than emergencies hence allowing a crucial time of 12–24 hours after birth for effective optimization. Early recognition and management of these risk factors have led to improved perioperative care. Thus, pediatric anesthesiologists dealing with surgical newborns need to be proficient in both preoperative preparation and intraoperative management of these babies. Availability of standard protocol for management of the sick newborns during perioperative period and their resuscitation in case of any adverse event will be of use to all personnel taking care of surgical neonates and will help in improving the outcomes of surgical neonates. Therefore, we propose a Neonatal Perioperative Resuscitation (NePOR) protocol for children less than 28 days of age undergoing surgery.

This review highlights the (1) causes and risk factors for neonatal morbidity and mortality, (2) preoperative surveillance and prevention for optimization of electrolyte imbalance and acid base abnormalities and the (3) common surgical conditions encountered in neonates and their associated metabolic and electrolyte disorders, and finally (4) resuscitation of a surgical neonate in the perioperative period.

Literature Search

A comprehensive literature search was done in PubMed, Goggle Scholar, Embase and Cochrane central register of controlled trials for studies relating to perioperative adverse events, peri arrest conditions and resuscitation in surgical neonates. Reviews, meta-analyses, and randomized clinical trials were included. Authors found 55 articles through search strategies and search engines. A total of 30 articles were included based on relevance, followed by proposition of resuscitation protocol for surgical neonate.

Causes and risk factors

Previous studies have highlighted factors other than anesthesia such as preoperative condition of the neonate, associated congenital malformations, and involvement of cardiac or gastrointestinal tract lesions, contribute to deaths in surgical neonates.[⁶⁷⁸] An early recognition and management of these risk factors leads to improved perioperative care and reduces morbidity and mortality.[²³⁴⁶⁷⁸]

Identification of risk factors

The risk factors for perioperative mortality in surgical neonates include i. American society of anesthesiologists (ASA) grade ii. prematurity iii. low birth weight iv. emergency surgery v. congenital malformations.

The extracted data from the POCA Registry and isolated single center studies analyzing the risk factors for mortality in surgical newborns highlighted ASA 3 and necrotizing enterocolitis/gastrointestinal perforation as independent risk factors for early mortality.[²] The risk of cardiac arrest increases linearly with increasing ASA status. Prematurity and low birth weight have further been correlated with poorer outcome after neonatal surgery. The neonates are mainly subjected to emergency surgery which is an independent risk factor for peri-operative mortality. Prematurity and preoperative congenital anomaly place the neonate at a higher risk for peri operative arrest.[²⁹¹⁰]

Causes of cardiac arrest

According to POCA the cause of perioperative arrest in neonates can either be due to patient related factors, surgery related factors or anesthesia related factors [Table 1].[⁹¹⁰]

Table 1: Causes of perioperative cardiac arrest

1. Patient-related factors—These include non-modifiable factors—low birth weight, prematurity, and congenital anomalies and modifiable factors in the form of acid base disturbances and electrolyte imbalance and coagulopathy. Neonates with underlying sepsis are more prone to develop perioperative arrest due to underlying electrolyte disturbances, acid base disorders and coagulopathy. Undiagnosed, uncorrected cardiac lesions can also lead to perioperative arrest by triggering lethal arrythmias or tetralogy spell.
2. Anesthesia-related factors—Inability to secure the airway or ventilate the neonate can lead to hypoxic cardiopulmonary arrest. Anesthetic overdose can cause myocardial depression.
3. Surgery-related factors— Other than the surgical pathology per se, accidental injury to a vital organ or major vessel, excessive vagal stimulation during surgical manipulation can result in asystole or life threatening arrythmias.

Pre-resuscitation surveillance and prevention of cardiac arrest in surgical neonate

Pre resuscitation surveillance: Initial evaluation

The first assessment includes evaluation of the neonate on the basis of color, breathing, consciousness and circulation.[¹¹¹²]

1. Color—
1. Pale: suggests anemia requiring arrangement of adequate blood and or postponing surgery if it is not urgent, to build up oxygen carrying capacity of blood pre-operatively.
2. Yellowish discoloration: suggests jaundice warranting avoidance of hepatotoxic drugs.
3. Bluish discoloration: In central areas may suggest underlying cardiac pathology and needs evaluation by means of transthoracic echocardiography.
2. Breathing—Normal respiratory rate for a neonate is 40-60/min. Any added sounds during auscultation (secretions, wheeze, spasm, conducted sounds from upper airway); presence of any stridor may suggest airway obstruction and warrants a thorough evaluation and preparation for airway management. Also look for presence of apnea (cessation of breathing for 20 seconds).
3. Conscious level—decreased/impaired level of consciousness could be due to inadequate oxygen supply to brain, presence of toxic metabolites, decreased substrate delivery (hypoglycemia) or brain dysfunction.
4. Circulation—Capillary refill time <3 seconds suggests dehydration. Heart rate of <60/min suggests poor central perfusion and chest compressions need to be initiated in neonates. Systolic, diastolic, and mean BP below the 95% confidence interval according to the gestational week is termed as hypotension warranting intervention. The presence of abnormal heart sounds or murmurs suggests congenital cardiac lesion.
5. Pulse Oximetry—Pulse oximetry screening is an important tool to detect congenital cardiac pathology in neonates. Pre and post ductal difference of more than in oxygen saturation >3% warrants evaluation of the child for congenital cardiac disease prior to surgery.[¹³]
6. Echocardiography—Targeted echocardiography is recommended in neonates in case of a suspicion of persistent pulmonary hypertension, right heart failure, pericardial effusion and even in the management of patent ductus arteriosus or congenital diaphragmatic hernia.[¹⁴]
7. Near-infrared Spectroscopy (NIRS)—NIRS measure tissue and cerebral oxygenation. Although, the role of NIRS in resuscitation protocols is still emerging, it can form a promising tool in management of hypoxemia. The numeric value measured gives regional oxygen saturation (rSO₂) and is called the “tissue oxygenation index (TOI)” (normal values: 55–85%). A value less than 55% warrants intervention.[¹⁵]

Prompt recognition and management of peri-arrest conditions

Prompt recognition and management of peri arrest conditions can help to avert impending arrest.[^12161718] A step wise approach to tackle some of the common peri-arrest conditions, namely hypoglycemia,[¹⁹] hypoxemia, laryngospasm,[¹⁶] airway obstruction, hypotension,[¹⁸] hyperkalemia,[¹⁷] anaphylaxis,[²⁰] and bradycardia[¹²] in the perioperative period is given in Figure 1.

Figure 1: Management of perioperative conditions. (a) hyperglycemia; (b) laryngospasm/airway obstrction; (c) hypotension; (d) hyperkalemia; (e) anaphylaxis; (f) bradycardia

Congenital cardiac conditions

In neonates with duct dependent lesions, to keep the ductus arteriosus patent is a lifesaving procedure. Prostaglandins infusion is used to maintain the patency of PDA and allow the mixing of systemic and pulmonary circulation and maintenance of both systemic and pulmonary circulation. The initial lower dose of PGE1 of 0.02 mcg/kg/min followed by 0.01 mcg/kg/min is efficacious.[²¹]

Neonatal surgical emergencies and associated abnormalities

Data from World Health Organization mentions, one in 33 infants born has one or more associated congenital anomalies like tracheoesophageal fistula (TEF), congenital diaphragmatic hernia (CDH), pyloric stenosis (PS), which might require urgent surgery.[²²] Table 2 highlights the concerns and optimization for these surgical emergencies.

Table 2: Checklist for resuscitation preparedness

Perioperative resuscitation for pulseless cardiac arres

Prompt recognition of cardiac arrest in the operating room minimizes the period of no flow, increases the chances return of spontaneous circulation (ROSC) and decreases the incidence of neurologic injury. This demands an effective communication and team effort [Figure 2]. The resuscitation team in the OT can include not only the pediatric anesthetists, but also the pediatric surgeons, scrub nurse, and the anesthesia/OT technician. NePOR teams should understand their duties and responsibilities [Figure 3].

Figure 2: Intraoperative cardiac arrest algorithm

Figure 3: Role of team members in case of perioperative cardiac arrest in a neonate

Checklist

Neonate-specific resuscitation checklist should be displayed near the resuscitation trolley in the neonatal operation theatre, ICU, and other areas such as pre-anesthesia room, post anesthesia care units (PACU) where the neonates are cared for. A list of equipment required during neonatal resuscitation is given in Table 3.

Table 3: Surgical Emergencies

Recognition of “need to resuscitate”

Recognition and immediate initiation of resuscitation plays a fundamental role in the successful outcome of the resuscitative efforts. Bradycardia and asystole are the first documented rhythms in majority of neonatal cardiac arrest. The indications for neonatal resuscitation include:

1. Heart rate <60/minute
2. Arterial blood pressure <5th centile
3. Cyanosis or dark colored blood in the surgical field
4. ECG waveform showing asystole
5. Loss of arterial blood pressure waveform
6. Loss of pulse oximeter waveform

Immediate Intervention

1. Check the monitor: Loss of waveforms on monitor is a warning which should not be ignored. A quick check to ensure that no cable/sensor disconnection has occurred helps in ascertaining the true situation.
2. Early Response
1. Notify the team: Immediately notify the surgeons and other OT staff.
2. Increase FiO₂ to 100% and switch off inhalational agents: During bradycardia, tissue hypoxia can ensue because of low cardiac output with reduced peripheral oxygen delivery leading to metabolic acidosis. High inspired oxygen tension will help in maximizing the oxygen saturation and, in turn, systemic oxygen delivery. Inhalational agents cause cardiovascular depression and can worsen the cardiovascular collapse, therefore should be switched off.
3. Optimize the position if possible: Supine position is the best position for resuscitation. Prompt action should be taken to optimize the position of the neonate to initiate cardiopulmonary resuscitation. However certain surgeries like tracheoesophageal fistula and meningomyelocele repair warrant lateral decubitus or prone position and changing the position can take time as the child may be strapped with attached monitoring and iv lines. In these situations, CPR should be started immediately, while the position is being optimized.
4. Initiate cardiopulmonary resuscitation[²⁸]: Immediate initiation of CPR should be done with chest compressions and airway management.
3. Airway Management: In the operation theatre settings generally, the neonates having a cardiopulmonary arrest during the surgical procedure are intubated. However, cessation of heart beat (asystole or HR <60/minute) at the time of induction of anesthesia before the airway has been secured, warrants immediate control and maintenance of airway either via mask ventilation or placement of endotracheal tube (ETT) or Laryngeal mask airway (LMA).

ETT for airway management

ETT is preferred over LMA as it prevents over distention of the stomach which can compromise effective ventilation, prevents the risk of aspiration and obliviates the need for cricoid pressure. However, insertion of ETT can be technically difficult especially in the presence of airway abnormalities and time consuming.

The size of ETT can be decided by the weight or gestation.[²⁹] Size 2.5 mm ETT is used in neonates weighing less than 1250 grams with gestational age of less than 32 weeks, size 3 mm ETT in neonates weighing between 1250 grams to 3000 grams with gestational age between 32 and 38 weeks and size 3.5 mm ETT is used in neonates more than 3000 grams with gestational age of more than 38 weeks. Owing to the increased incidence of difficult intubation in neonates, 0.5 mm size smaller ETT should be kept ready.

In a premature infant the ETT should be fixed at 8–9 cm at the lip while in term neonate at 9–10 cm. An alternative to assess ETT length is by the rule of six i.e. Oral tube length (cm) =6 + wt (kg). These formulas can only guide. Proper positioning needs to be confirmed clinically by auscultation and capnograph.

Cuffed Vs. Uncuffed ETT: Either cuffed (CETT) or uncuffed ETT can be used to secure the airway. Age based recommendations for cuffed endotracheal tubes in neonates and infants have been provided by Khine et al. and Salgo et al.[³⁰³¹]

Role of laryngeal mask airway (LMA)

So far there is no substantial data to prove the advantage of LMA during neonatal resuscitation, especially in neonates <34 weeks of gestation and 2000 gm. A recent review suggested the safe efficacy of LMA for newborn resuscitation in the delivery room.[³²]

Indications for the use of LMA include LMA already in situ, difficult intubation, and inexperienced anesthesiologist.

Chest compressions

Chest compressions should be initiated if heart rate falls below 60/min, at the lower half of the sternum using preferably two thumbs with hands encircling the chest at a ratio of 3 compression: 1 ventilation. Two fingers technique is less effective and leads to faster rescuer fatigue.

Resuscitation medications

Route of medication

Intravenous route is preferred for administering drugs, as surgical neonates generally have an intravenous catheter in place. In cases of difficulty in securing iv access as seen during circulatory collapse alternate routes like intraosseous (IO) or through ETT can be used. ETT route require drugs to be delivered at 2.5–10 times the dose administered through intravenous or IO route. Despite having the same effectiveness as intravenous, IO route is not commonly used.

Drugs during resuscitation

Epinephrine: 0.01–0.03 mg/kg epinephrine in 1:10,000 (0.1 mg/ml) concentration should be given after 2-3 minutes by intravenous route. 0.1–0.3 mg/kg endotracheal epinephrine in 1:10,000 (0.1 mg/ml) concentration can be given when intravenous line is not established.

Fluid—In cases of suspected hypovolemia 10 ml/kg of normal saline or lactated Ringer should be infused.

Sodium bicarbonate: In cases of suspected or confirmed metabolic acidosis, diluted sodium bicarbonate (4.2%) can be given in a dose of 2 meq/kg over 2 minutes.

Intraoperative resuscitation for hypoxic arrest

Inability to ventilate a neonate is one the most important cause of perioperative cardiac arrest. Desaturation or hypoxemia can precipitate to bradycardia and as already discussed bradycardia is the most commonly encountered lethal cardiac arrest rhythm in a neonate.

Post resuscitation care

As soon as there is ROSC, a systematic approach is required to identify and treat the cause of cardiac arrest and prevent any neurological or other organ system injuries. This consists of 2 phases:

In the first phase we have to continue advanced life support resuscitation in view of immediate life-threatening conditions

In second phase support the various organ systems, like cardiac, renal, gastrointestinal, neurological etc.

1. Maintain normotension and normal tissue perfusion
Invasive blood pressure which should be maintained within 20% of baseline. If there are signs of inadequate perfusion, give lactated Ringers 10 ml/kg over 5–10 min.
Administer dobutamine/dopamine to increase cardiac output, if sepsis is suspected start with noradrenaline infusion.

2. Maintain oxygenation and ventilation
Oxygen levels should be titrated to keep saturation between 94 and 99% (arterial oxygen tension between 60 and 300 mmHg). In preterm neonates recommended oxygen saturation levels are 91–95%.[³³³⁴³⁵]

3. Maintain normothermia
Maintain normal temperature of neonate (core temperature monitoring) avoiding hyperthermia (>38 degree C) or hypothermia (<32 degree C) to take place.
Maintain normoglycemia
Try to keep blood glucose levels <180 mg/dl, avoid hypoglycemia (<60 mg/dl)

4. Maintain normal metabolic milieu
Get arterial blood gas analysis done, to look for metabolic acidosis, try to keep pH >7.30

5. Treat seizures
Seizures need to be treated aggressively using phenobarbitone, benzodiazepines or anesthetic agents.

6. Correct dyselectrolytemias
7. Maintain renal perfusion
Monitor urine output keeping >1 ml/kg/hour

8. Maintain hematocrit
Correct anemia and maintain hematocrit levels to 45–55% to preserve oxygen carrying capacity of blood.

Post-resuscitation drugs:

Glucose: 2 ml/kg of 10% dextrose (200 mg/kg) IV

Nalaxone: 0.1 mg/kg rapidly IV or IM.

Phenobarbital (seizures): 20 mg/kg slow IV push.

Dopamine (hypotension): 2 to 20 mcg/kg/min IV infusion.

Breaking bad news to parents and family

Both anesthetist and surgeon as a team should share the responsibility of breaking the bad news to parents.[¹²] Parents should be handled with utmost politeness and diligence. One staff member should guide the parents and be with them after breaking the bad news.

Summary

Neonatal perioperative resuscitation requires teamwork from nurses, surgeons, and anesthesiologists. It is important to understand the likely causes of perioperative arrest in neonates, optimize them prior to surgery, understand what skills are needed for resuscitation and practice these infrequently used skills.

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Conflicts of interest

There are no conflicts of interest.