Discuss the peri-operative problems and anaesthetic management of a two day old child scheduled to undergo TEF repair?
TEF is a fistulous
communication between the trachea and esophagus, occurring due to defective
embryogenesis. This communication is close to the carina and clinically presents at birth. It is
usually associated with an atresia of the esophagus, which ends as a blind upper pouch in the
neck or upper thorax, the distance between the upper and lower esophagus is variable.
ANOMALIES ASSOCIATED WITH TEF
Vertebral. Scoliosis and other vertebral defects
Anorectal. Imperforate anus,malrotation and duodenal atresia
Cardiac. ASD,VSD,PDA,TOF,right sided aortic arch
Renal. Renal agenesis ,dysplasia, polycystic kidneys,horseshoe kidney
Limb. Radial anomalies ,polydactyle
ANOMALIES ASSOCIATED WITH TEF
Vertebral. Scoliosis and other vertebral defects
Anorectal. Imperforate anus,malrotation and duodenal atresia
Cardiac. ASD,VSD,PDA,TOF,right sided aortic arch
Renal. Renal agenesis ,dysplasia, polycystic kidneys,horseshoe kidney
Limb. Radial anomalies ,polydactyle
PATHOPHYSIOLOGY
The two main problems in the newborn with TEF are
1. Aspiration pneumonitis –saliva, oral secretions and oral feeds pool in the blind upper
pouch and overflow into the trachea. Gastric secretions enter the lungs through the fistula.
Bag and mask ventilation in the newborn with TEF is avoided because this causes air to enter the stomach via the fistula, causing distention of the stomach, which hinders ventilation by tenting the diaphragm. Further distension, especially in a ventilated infant, may cause rupture of stomach and Pneumoperitoneum. This situation dictates early gastrostomy to provide a vent for the gases.
2. Dehydration – In the fetus the first sign of esophageal atresia may be Polyhydramnios in the mother.Atresia of the esophagus leads to an inability to swallow amniotic fluid leading to dehydration in the fetus and Polyhydramnios in the mother
PREOPERATIVE STABILIZATION
The two main problems in the newborn with TEF are
1. Aspiration pneumonitis –saliva, oral secretions and oral feeds pool in the blind upper
pouch and overflow into the trachea. Gastric secretions enter the lungs through the fistula.
Bag and mask ventilation in the newborn with TEF is avoided because this causes air to enter the stomach via the fistula, causing distention of the stomach, which hinders ventilation by tenting the diaphragm. Further distension, especially in a ventilated infant, may cause rupture of stomach and Pneumoperitoneum. This situation dictates early gastrostomy to provide a vent for the gases.
2. Dehydration – In the fetus the first sign of esophageal atresia may be Polyhydramnios in the mother.Atresia of the esophagus leads to an inability to swallow amniotic fluid leading to dehydration in the fetus and Polyhydramnios in the mother
PREOPERATIVE STABILIZATION
Keep nil oral
Head up position – to prevent regurgitation of stomach contents
suction catheter – a slow suction applied to the upper pouch.This makes sure there is no pooling of saliva overflowing into the trachea.
IV access. IV fluids to correct dehydration and avoid hypoglycemia- isotonic solution like NS may be given correct dehydration . 5% Dextrose with 1/4th Normal saline to prevent hypoglycemia.
Correction of acid base abnormalities.
Antibiotics –Inj. Ampicillin/ gentamicin
Inj. Vit.K 1mg IV/IM. (0.5mg if wt< 1500g)
ECHO – to find out associated cardiac anomaly and to look for right sided aortic arch. Evaluation of other anomalies – Chest and abdominal xray.,Renal ultrasound.
Optimisation of Respiratory status.This may range from simple oxygen supplementation to CPAP mask to more invasive methods.If pneumonia is severe infant may need intubation and ventilation in NICU in which case Endotracheal tube is positioned in such a way as to not ventilate the fistula and minimal pressure settings are used. In such babies gastric inflation must be monitored as it can impede ventilation as already explained.
a preop rigid Bronchoscopy usually just before surgery to define site of entry of distal TEF as well as to assess the degree of tracheomalacia.
Anaesthetic Management
The major anesthetic issues include (1) evaluation for aspiration pneumonia; (2) overdistention of the stomach from entry of air directly into the stomach through the fistula; (3) inability to ventilate the child because of the large size of the fistula; (4) problems associated with other anomalies, particularly a patent ductus arteriosus (shunting) and other forms of congenital heart disease; and (5) the need for postoperative intensive care.
Generally, an “awake sedated” intubation is performed with administration of 0.5 to 1 µg/kg offentanyl and 25 to 50 µg/kg of midazolam and topicalize the tongue, larynx, and vocal cords with no more than 5 mg/kg of lidocaine (1.0%).
The endotracheal tube is intentionally passed into the right main bronchus and then slowly withdrawn until breath sounds are heard on the left. Often this technique ensures that the tip of the endotracheal tube is placed beyond the origin of the fistula, thus avoiding massive distention of the stomach.
Care must be taken to avoid rupturing the stomach, so spontaneous and gently assisted ventilation may be appropriate until the fistula is ligated or a gastrostomy is completed. A change in the distance of insertion of the endotracheal tube of as little as 1 to 2 mm may determine whether the anesthesiologist is ventilating both lungs, one lung, or the fistula. Therefore, because a change in oxygen saturation may be the first indication that all is not well, the pulse oximeter is one of the most useful monitors in managing these children. A preductal and postductal location (two pulse oximeters) will diagnose intracardiac shunting. Taping the stethoscope to the left side of the chest in the axilla also decreases the possibility of unrecognized endobronchial intubation. Some surgeons prefer that the infant remain intubated postoperatively, whereas others prefer an attempt at extubation; it should be noted that approximately 30% will require reintubation for clearing of secretions.
Intraoperative temperature maintenance
Postoperative pain may be managed with a caudal catheter threaded up to the thoracic level and either intermittent bupivacaine (1 to 2 mL of 0.125% with epinephrine 1 : 200,000) administered every 6 to 8 hours or a continuous infusion of chloroprocaine (1.5%) with fentanyl (0.4 µg/mL) infused at 0.3 to 0.8 mL/kg/hr. Note that such management may be undertaken only with the full support of a pediatric pain service.
Head up position – to prevent regurgitation of stomach contents
suction catheter – a slow suction applied to the upper pouch.This makes sure there is no pooling of saliva overflowing into the trachea.
IV access. IV fluids to correct dehydration and avoid hypoglycemia- isotonic solution like NS may be given correct dehydration . 5% Dextrose with 1/4th Normal saline to prevent hypoglycemia.
Correction of acid base abnormalities.
Antibiotics –Inj. Ampicillin/ gentamicin
Inj. Vit.K 1mg IV/IM. (0.5mg if wt< 1500g)
ECHO – to find out associated cardiac anomaly and to look for right sided aortic arch. Evaluation of other anomalies – Chest and abdominal xray.,Renal ultrasound.
Optimisation of Respiratory status.This may range from simple oxygen supplementation to CPAP mask to more invasive methods.If pneumonia is severe infant may need intubation and ventilation in NICU in which case Endotracheal tube is positioned in such a way as to not ventilate the fistula and minimal pressure settings are used. In such babies gastric inflation must be monitored as it can impede ventilation as already explained.
a preop rigid Bronchoscopy usually just before surgery to define site of entry of distal TEF as well as to assess the degree of tracheomalacia.
Anaesthetic Management
The major anesthetic issues include (1) evaluation for aspiration pneumonia; (2) overdistention of the stomach from entry of air directly into the stomach through the fistula; (3) inability to ventilate the child because of the large size of the fistula; (4) problems associated with other anomalies, particularly a patent ductus arteriosus (shunting) and other forms of congenital heart disease; and (5) the need for postoperative intensive care.
Generally, an “awake sedated” intubation is performed with administration of 0.5 to 1 µg/kg offentanyl and 25 to 50 µg/kg of midazolam and topicalize the tongue, larynx, and vocal cords with no more than 5 mg/kg of lidocaine (1.0%).
The endotracheal tube is intentionally passed into the right main bronchus and then slowly withdrawn until breath sounds are heard on the left. Often this technique ensures that the tip of the endotracheal tube is placed beyond the origin of the fistula, thus avoiding massive distention of the stomach.
Care must be taken to avoid rupturing the stomach, so spontaneous and gently assisted ventilation may be appropriate until the fistula is ligated or a gastrostomy is completed. A change in the distance of insertion of the endotracheal tube of as little as 1 to 2 mm may determine whether the anesthesiologist is ventilating both lungs, one lung, or the fistula. Therefore, because a change in oxygen saturation may be the first indication that all is not well, the pulse oximeter is one of the most useful monitors in managing these children. A preductal and postductal location (two pulse oximeters) will diagnose intracardiac shunting. Taping the stethoscope to the left side of the chest in the axilla also decreases the possibility of unrecognized endobronchial intubation. Some surgeons prefer that the infant remain intubated postoperatively, whereas others prefer an attempt at extubation; it should be noted that approximately 30% will require reintubation for clearing of secretions.
Intraoperative temperature maintenance
Postoperative pain may be managed with a caudal catheter threaded up to the thoracic level and either intermittent bupivacaine (1 to 2 mL of 0.125% with epinephrine 1 : 200,000) administered every 6 to 8 hours or a continuous infusion of chloroprocaine (1.5%) with fentanyl (0.4 µg/mL) infused at 0.3 to 0.8 mL/kg/hr. Note that such management may be undertaken only with the full support of a pediatric pain service.
No comments:
Post a Comment