Cyanosis surgery
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Cardiac catheterization
- Cardiac catheter interventions can be palliative by improving cyanosis or be corrective by relieving obstruction to flow.
- Balloon valvuloplasty can be effective in patients with critical pulmonary stenosis or aortic stenosis. Selected patients with pulmonary atresia are also candidates for balloon valvuloplasty if the obstruction is membranous, the tricuspid annulus and right ventricular size are adequate to support a two ventricle repair, and the coronary circulation does not depend upon the right ventricle [10].
Respiratory distress syndroem
Surfactant therapy
Exogenous surfactant replacement therapy is effective in reducing RDS mortality and morbidity in preterm infants [27-30]. Several clinical trials have shown the benefit of surfactant administration in preterm infants born less than 30 weeks gestation who are at the greatest risk for RDS [27,29,31,32]. In these trials, surfactant therapy compared with placebo was associated with a lower incidence and severity of RDS and mortality, and a decreased rate of associated complications including BPD, pulmonary interstitial emphysema, and other pulmonary leak complications, such as pneumothorax [27,29,31,32].
When surfactant therapy is used, the following issues must be addressed:
●Selection of surfactant preparation
●Indications for surfactant therapy
●Timing of administration
●Technical aspects of administration
Types of surfactant
Surfactant preparations include natural and synthetic surfactants. Although both types of surfactant preparations are effective, natural surfactants have been shown to be superior in clinical trials to synthetic preparations that did not contain protein B and C analogues [3,33,34]. In particular, the use of natural preparations was associated with lower inspired oxygen concentration and ventilator pressures, decreased mortality, and lower rate of RDS complications in preterm infants.
Three natural surfactants derived from either bovine or porcine lungs are commercially available in the United States (table 1). It appears that there are no clinically significant differences amongst the three preparations [35,36]:
●Poractant alfa – Porcine lung minced extract
●Calfactant – Bovine lung lavage extract
●Beractant – Bovine lung minced extract
Additional doses of surfactant therapy are administered if the patient has a persistent requirement of an FiO2 >0.30. Subsequent surfactant administration may decrease mortality and morbidity in infants less than 30 weeks gestation with RDS [27,39].
If the infant maintains adequate respiratory efforts and has an FiO2 requirement less than 0.30, no additional doses of surfactant are needed and the patient can be extubated to nCPAP [27,39].
Timing — If surfactant therapy is used, it is most effective when given within the first 30 to 60 minutes of life following placement of a pulse oximeter and clinical confirmation of correct endotracheal tube placement. However, the potential benefits of timely administration of surfactant must be balanced with adequate time for an initial trial of nCPAP [27,40,41].
Surfactant administration technique
Endotracheal administration — Endotracheal intubation has been the standard technique of surfactant administration. However, surfactant administration may be complicated by transient airway obstruction [3,42] or inadvertent instillation into only the right main stem bronchus if the endotracheal tube is advanced too far in the airway. During administration, oxygen saturation needs to be monitored, as oxygen desaturation may occur. Other complications associated with intubation and mechanical ventilation include pulmonary injury due to volutrauma and barotrauma associated with intermittent positive pressure ventilation, pulmonary air leak, and airway injury due to intubation. (See 'Endotracheal tube complications' below.)
Less invasive measures — Due to the complications from the delivery of surfactant by intubation, minimal or less invasive administrative techniques have been developed and appear promising. These interventions include aerosolized surfactant preparations, laryngeal mask airway-aided delivery of surfactant, pharyngeal instillation, and the use of thin intratracheal catheters [43-49].
However, evidence is of moderate quality that support their use over the traditional endotracheal administration. As a result, we continue to administer surfactant through the endotracheal route until there are conclusive data of the effectiveness, safety, and generalizability of these new noninvasive techniques. The use of less invasive measures to administer surfactant has expanded, especially in European centers [50]. However, there is wide variation in the administration and techniques used and in patient selection.
Surfactant in combination with budesonide
Limited data in preterm infants with severe RDS requiring mechanical ventilation suggest that the combination of surfactant and budesonide(corticosteroid) reduced the incidence of BPD and the composite outcome of death and BPD [55]. There was no difference in mortality. However, there were several limitations raising concern of bias, including small number of patients, studies performed by the same group, incomplete blindness in the study design, and follow-up of the entire cohort at two to three years of age. As a result, the combination of surfactant and budesonide cannot be recommended until there are larger studies that show definite benefit that outweighs any adverse effect of the intervention.
Inhaled nitric oxide
Data from clinical trials show that the use of inhaled nitric oxide (iNO) either as rescue or routine therapy is not beneficial in preterm infants with RDS in reducing mortality or the risk of BPD. As a result, we concur with the 2014 AAP clinical report and the ECG guidelines that iNO should not be used to treat preterm infants with RDS except in rare cases of pulmonary hypertension or hypoplasia [2,56]. The evidence is discussed in greater detail separately.
Thermoregulation
Infants should be maintained in a thermal neutral environment to minimize heat loss and maintain the core body temperature in a normal range, thereby reducing oxygen consumption and caloric needs. The ambient temperature should be selected to maintain an anterior abdominal skin temperature in the 36.5 to 37ºC range. Rectal temperatures should be avoided in infants with RDS because of the greater risk of trauma or perforation associated with their use. As a result, abdominal temperatures are used to set the servo-controlling temperatures in incubators and in radiant warmers. (See "Short-term complications of the preterm infant", section on 'Hypothermia'.)
Fluid management
Fluids should be adjusted to maintain a slightly negative water balance, as infants are born in a positive fluid state. Excessive fluid intake may increase the risk of patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), and bronchopulmonary dysplasia (BPD) [57] and should be avoided.
There is no evidence to support the routine use of diuretics (particularly furosemide) in preterm infants with RDS [58]. Diuretic use should be avoided because it often results in serum electrolyte abnormalities, and in the case of loop diuretics, nephrocalcinosis, especially hyponatremia and hypokalemia, due to urinary loss of sodium and potassium. (See "Fluid and electrolyte therapy in newborns", section on 'Disorders of sodium balance'.)
Cardiovascular management
Cardiovascular management is focused on ensuring adequate perfusion for all patients. Systemic hypotension occurs commonly in the early stages of RDS. As a result, blood pressure should be frequently monitored noninvasively or continuously via intravascular catheter. However, intervention is not usually required for extremely low birth weight (ELBW) infants (BW <1000 g) with adequate perfusion. In contrast, infants with poor perfusion are in shock and require resuscitation to stabilize their hemodynamic state. (See "Etiology, clinical manifestations, evaluation, and management of low blood pressure in extremely preterm infants", section on 'Management approach' and "Etiology, clinical manifestations, evaluation, and management of neonatal shock".)
PDA is common in preterm infants with RDS. It may manifest as hypercapnia and contribute to difficulties in weaning from mechanical ventilation, which may predispose the patient to BPD. The clinical features, diagnosis, and management of PDA in preterm infants are discussed separately. (See "Pathophysiology, clinical manifestations, and diagnosis of patent ductus arteriosus in premature infants" and "Management of patent ductus arteriosus in preterm infants".)
Pulmonary atresia
- Cardiac catheterization is done to evaluate the defect or defects of the heart; this procedure is much more invasive.
- The patient will need to have a series of surgeries to improve the blood flow permanently.
- The type of surgery recommended depends on the size of the right ventricle and the pulmonary artery. If they are normal in size and the right ventricle is able to pump blood, open heart surgery can be performed to make blood flow through the heart in a normal pattern. If the right ventricle is small and unable to act as a pump, doctors may perform another type of operation called the Fontan procedure. In this two-stage procedure, the right atrium is disconnected from the pulmonary circulation. The systemic venous return goes directly to the lungs, by-passing the heart. The first surgery will likely be performed shortly after birth. A shunt can be created between the aorta and the pulmonary artery to help increase blood flow to the lungs. As the child grows, so does the heart and the shunt may need revised in order to meet the body's requirements.
- A cardiac catheterization procedure can be used as a diagnostic procedure, as well as initial treatment procedure as balloon atrial septostomy to improve mixing oxygenated blood and unoxygenated blood between the right and left atria.
- Atrial Septostomy: a special catheter with a balloon in the tip is used to create an opening in the atrial septum. The catheter is guided through the foramen ovale to the left atrium (LA). Once the ballon is in the LA is inflated and then pulled back opening a bigger hole between the right atrium and the LA to mix blood.
- If the hospital does not have a catheterization lab with skill physician to perform the ballon atrial septostomy, an intravenous medication called prostaglandin is administered to keep the ductus arteriousus from closing.
Transposition of great arteries
Palliative interventions
- Cardiac catheterization
- Rashkind balloon atrial septostomy
- Balloon angioplasty
- Endovascular stenting
- Angiography
Cardiac catheterization is a minimally invasive procedure which provides a means of performing a number of other procedures.
- A balloon atrial septostomy is performed with a balloon catheter, which is inserted into a foramen ovale, PFO, or ASD and inflated to enlarge the opening in the atrial septum; this creates a shunt which allows a larger amount of red blood to enter the systemic circulation.
- Angioplasty also requires a balloon catheter, which is used to stretch open a stenotic vessel; this relieves restricted blood flow, which could otherwise lead to CHF.
- An endovascular stent is sometimes placed in a stenotic vessel immediately following a balloon angioplasty to maintain the widened passage.
- Angiography involves using the catheter to release a contrast medium into the chambers and/or vessels of the heart; this process facilitates examining the flow of blood through the chambers during an echocardiogram, or shows the vessels clearly on a chest x-ray, MRI, or CT scan - this is of particular importance, as the coronary arteries must be carefully examined and "mapped out" prior to the corrective surgery.
It is commonplace for any of these palliations to be performed on a TGA patient.
Moderate
- Left anterior thoracotomy
- Isolated pulmonary artery banding (PAB)
- Left lateral thoracotomy
- PAB (when coarctation or aortic arch repair also required)
- Right lateral thoracotomy
- Blalock-Hanlon atrial septectomy
Each of these procedures are performed through an incision between the ribs and visualized by echocardiogram; these are far less common than heart cath procedures.
Pulmonary artery banding is used in a small number of cases of d-TGA, usually when the corrective surgery needs to be delayed, to create an artificial stenosis in order to control pulmonary blood pressure; PAB involves placing a band around the pulmonary trunk, this band can then be quickly and easily adjusted when necessary.
An atrial septectomy is the surgical removal of the atrial septum; this is performed when a foramen ovale, PFO, or ASD are not present and additional shunting is required to raise the oxygen saturation of the blood.
Major
- Median sternotomy
- PAB (when intracardiac procedures also required)
- Concomitant atrial septectomy
In recent years, it is quite rare for palliative procedures to be done via median sternotomy. However, if a sternotomy is required for a different procedure, in most cases all procedures that are immediately required will be performed at the same time.
Total anomalus pulmonary venous return
Surgery should be performed as soon as possible in the patients of total anomalous pulmonary venous connection. The surgical procedure varies depending upon the anatomy of the TAPVC lesion.
- Supracardiac and infracardiac TAPVC: Connection is created between the pulmonary veins and the left atrium. The vertical vein is tied up so that the abnormal blood flow could be prevented.
- Pulmonary veins directly connected to the superiorvenacava: An intracardiac baffle is created that helps in transfer of blood from the right atrium, through atrial septum into the left atrium.
- Intracardiac (pulmonary vein connected to the coronary sinus): Coronary sinus is incised and connected to left atrium.
- Intracardiac (pulmonary vein opening directly into the right atrium): A interatrial connection is made and the blood is redirected from right atrium to left atrium.
Tricuspid atresia
First stage
First stage of surgery is performed in the neonatal period. The goals of the initial palliation are to ensure that blood exiting the right atrium (RA) is unimpeded, provides adequate pulmonary blood flow, protects the pulmonary artery bed from high pressures that could result in higher risk for subsequent operations, and ensures unobstructed flow from the left ventricle (LV) to the aorta. Choices for intervention are dependent on the anatomic variants as follows (table 1):
●TV atresia with normally related great arteries (type I):
•With diminished pulmonary blood flow, the initial surgery soon after birth aims to restore a reliable source of pulmonary blood flow with a modified Blalock-Taussig shunt (shunt from the innominate artery into the central pulmonary artery) (figure 4).
•In the presence of unobstructed pulmonary blood flow (type Ic), a pulmonary artery band may be placed in early infancy to restrict the amount of pulmonary blood flow and protect the pulmonary bed from high systemic pressures. As mentioned above, the vast majority of ventricular septal defects (VSDs) decrease in size over time and restrict pulmonary blood flow. A pulmonary artery band, therefore, may not be required in all patients who have unobstructed pulmonary flow at birth through a VSD, and could be restricted to patients who are symptomatic despite maximal medical therapy for pulmonary congestion/heart failure. Furthermore, a pulmonary artery band may stimulate myocardial hypertrophy that may more rapidly reduce the size of the VSD.
•Rarely, the degree of restriction to pulmonary blood flow is enough to maintain adequate oxygenation without pulmonary overcirculation and heart failure. These patients may not require surgery in the neonatal period and can be taken directly to the second stage of palliation.
●TV atresia with transposition of great arteries (type II):
•In the presence of significant subaortic obstruction with a restrictive VSD, enlargement of the VSD or a Damus-Kaye-Stansel anastomosis (anastomosis between the main pulmonary artery and ascending aorta) with a modified Blalock-Taussig shunt is the initial surgery of choice.
•If an isolated coarctation is present, it should be relieved and a pulmonary artery band may be considered to restrict pulmonary blood flow.
•Similar to type I lesions, in a few cases, the size of the VSD is large enough to maintain systemic output, in which case a pulmonary artery band alone may be adequate.
Second stage — The second palliative procedure for both type I and type II lesions is a cavopulmonary anastomosis (Glenn procedure). This stage of palliation is typically performed at three to six months of life when infants experience progressive cyanosis as they begin to outgrow their neonatal shunt. This surgery involves removal of the original shunt, and direct anastomosis of the superior vena cava to the right pulmonary artery. The Glenn procedure relies on passive venous drainage from the superior vena cava directly into the pulmonary artery. However, there is persistent systemic desaturation due to continued inferior vena cava flow into the RA. In a case series of 557 patients who underwent second stage palliation for single ventricle anatomy from 1998 to 2010, the overall mortality rate was low (4.7 percent) and there were no deaths in the 12 percent of patients who had TV atresia [25]
Tetralogy of fallot
Palliative surgery
- The surgery involved forming an anastomosis between the subclavian artery and the pulmonary artery.
- The Pott shunt and the Waterson procedure are other shunt procedures which were developed for the same purpose.
- Potts shunt: Shunt between left pulmonary artery and descending aorta.
- The technique has been modified and is usually performed using a Gortex tube to create the connection.
- Waterson shunt: Shunt between right pulmonary artery and ascending aorta.
Total Surgical Repair
- The surgery generally involves:
- Making incisions into the heart muscle, relieving the right ventricular outflow tract stenosis by careful resection of muscle
- Repairing the VSD using a Gore-Tex or Dacron patch or a homograft.
- Additional reparative or reconstructive work may be done on patients as required by their particular anatomy.
- The repair could be done by either of the approaches i.e.transatrial or transpulmonary
Coarcitation of aorta
Indications for Surgery
- There is a lack of consensus for the indications and the time for surgery. Some groups of surgeon consider balloon angioplasty and stenting as the initial approach and reserving surgery for more complicated conditions or treatment failures. Whereas, others consider surgical repair as the first line of therapy.
- Surgery is the first choice in aortic coarctations involving:
- Long length of aorta
- Severe coarctations causing almost complete or complete obliteration of the aortic lumen.
- Associated with other cardiac defects for e.g. large patent ductus arteriosus, ventricular septal defect.
Surgical Techniques
- The choice of technique depends on the patient's age at presentation, size, associated abnormalities, and anatomy of the coarctation.
- Surgical approach - median sternotomy is preferred over left lateral thoracotomy, in complex arch repairs.
- Subclavian flap aortoplasty is found to be the most commonly performed followed by resection in end-to-end anastomosis, patch aortoplasty, and bypass graft when the surgery is done during infancy. Whereas, in children and adolescent undergoing coarctation repair end-to-end anastomosis is commonest followed patch aortoplasty and subclavian flap aortoplasty.
- Patch aortoplasty are less frequently used these days because of concerns regarding the development of aortic aneurysm at the site of surgery.
- Available Techniques:
- Resection and end-to-end anastomosis
- Patch aortoplasty
- Left subclavian flap aortoplasty
- Tubular bypass grafts
- Combination techniques
Atrial septal defect
- Surgical closure is the most common method of treatment method for atrial septal defect and has been the gold standard for many years. Many surgeons prefer more minimally invasive techniques over the conventional sternotomy to avoid potentials for additional complications. Special consideration must be taken into account for the age of the patient and the size of the defect involved. Surgical closure is indicated for patients with primum, sinus venosus and coronary sinus type of atrial septal defects. However, ostium secundum atrial septal defects are commonly treated by percutaneous closure. With uncomplicated atrial septal defect, (without pulmonary hypertension and other comorbidities) the post-surgical mortality is as low as 1%. Minimally invasive repair of atrial septal defect has been shown to be as successful as the conventional sternotomy. Although they have not been associated with reduced morbidity and mortality rates, they have been proven to have the advantage of being less invasive, less post-surgical complications, decreased hospital stay, and more cosmetic benefits.
Pulmonary hypertension
- The choice of treatment for pulmonary hypertension requires the assessment of the clinical severity of the disease and the identification of any underlying cause.
- Patients who have PH secondary to a medical condition such as left heart failure, lung diseases, or thromboembolic disease should receive treatment for the underlying cause.
- Patients who have pulmonary arterial hypertension (PAH) must undergo vasoreactivity testing in order to assist in the selection of the optimal therapy which includes calcium channel blockers, endothelin receptor antagonist, phosphodiesterase inhibitors, or prostanoids.
- Surgical intervention such as atrial septostomy or lung transplantation should be considered among patients with pulmonary arterial hypertension who fail to improve on optimal therapy or when medical therapy is unavailable.
- Failure of clinical improvement among PAH patients with WHO functional class II or III is defined as either:
- A stable and unsatisfactory clinical status, or
- An unstable and deteriorating Failure of clinical improvement among PAH patients with WHO functional class IV is defined as either:
- Absence of quick improvement to a WHO functional class III or less, or
- A stable and unsatisfactory clinical status
Atrial Septostomy
- Atrial septostomy is a surgical procedure that creates a shunt between the right and left atria.
- It relieves pressure on the right side of the heart, but at the cost of lower oxygen levels in blood (hypoxia). It is best performed in experienced centers.
- Graded balloon dilatation of atrial septostomy is the recommended type of atrial septostomy.
- Atrial septostomy might be considered among PH patients with WHO functional class IV and right heart failure refractory to therapy.
- Atrial septostomy should also be considered among PH patients who have Eisenmenger's syndrome, idiopathic PAH, and those awaiting lung transplantation.
Lung Transplantation
- Lung transplantation is considered in the treatment of patients with idiopathic PH, PH associated with congenital heart disease, or pulmonary veno-occlusive disease (PVOD) who fail to improve on optimal medical therapy.
- Combined lung and heart transplantation might be considered in selected patients.
- According to the Registry of the International Society for Heart and Lung Transplantation, the survival rates following lung transplantation are 61%, 49%, and 25 % at 3, 5, and 10 years respectively.
Pulmonary Thromboendarterectomy
- Pulmonary thromboendarterectomy (PTE) is a surgical procedure that is used for the treatment of chronic thromboembolic pulmonary hypertension.
- It is the surgical removal of an organized thrombus along with the lining of the pulmonary artery.
- PTE is a large and very difficult procedure that is currently performed in a few select centers. Case series show remarkable success in most patients.
- Treatment for hypoxic and miscellaneous varieties of PH have not been established. However, studies of several agents are currently enrolling patients. Many physicians will treat these diseases with the same medications as for PAH, until better options become available.