MICS Pediatric Heart Surgeries and Adult Congenital Heart Surgery.

Overview

The surgical approach has always been chosen according to the patient’s age, gender, and specific patient’s request, balancing safety and effectiveness of the operation and patient’s satisfaction after the operation (according to the “gender-differentiated minimally invasive surgery” protocol [7]). For example, a right anterior mini-thoracotomy (RAMT) is less visible in adult females when the incision is within the submammary sulcus. An axillary lateral mini-thoracotomy (RALMT) is currently offered to both male and females whose weight is higher than 10 kg, for repair of simple CHD such as ASD, partial anomalous pulmonary venous drainage (PAPVD), discrete subaortic stenosis (SAS), membranous ventricular septal defect (VSD), and partial atrioventricular septal defects (p-AVSD). On the contrary, some kind of a mini-sternotomy (MS), meant as limited to the body of the sternum, is offered mostly to infants and children, weighing less than 10 kg, in order to repair lesions other than ASD, such as large VSD with significant left to right shunt in 3–6-month-old infants. In fact, according to our experience, this approach with the help of an appropriate retractor (Bookwalker retractor, Codman Surgical instruments, GS Medical Ltd., Dublin) can guarantee an excellent exposure of the great vessels when other maneuvers are required (i.e., aortic cross-clamping, pulmonary valvotomy, closure of patent ductus arteriosus (PDA)). In addition to these approaches, a right posterior mini-thoracotomy (RPMT) has occasionally been offered as a surgical option in older children and young females, to approach the aortic valve, SAS repair, and VSD closure. Also, from June 2006, as a refinement of our minimally invasive protocol, we have routinely employed peripheral cannulation (usually through right groin vessels) for the cardiopulmonary bypass in patients with simple CHD and a bodyweight superior to 15 kg.

Last, as part of our minimally invasive armamentarium, a video-assisted thoracoscopic surgery (VATS) has also been widely utilized since 1994, for the correction of simple CHD as PDA and vascular rings. However, after the introduction of percutaneous closure of restrictive PDA, we have drastically reduced this practice.

Transesophageal echocardiography

Routine TEE imaging is helpful in the surgical repair of CHD in children. Performance of TEE in these patients submitted to MICS represents a great contributor to the overall excellence in outcome for CHD. The TEE that has been used intraoperatively since the 1980s [17, 18] is a mainstay of monitoring during simple and complex pediatric cardiovascular surgery [19, 20], especially in MICS, since it provides dynamic control and intraoperative anatomical information but also:

  • Allows the surgeon to review the anatomical findings preoperatively.

  • Can diagnose myocardial performance.

  • Provides an evaluation of postsurgical results and can show residual shunts or other surgical problems that can be addressed during the same operative time (avoiding repeat surgery and its associated costs [21, 22]).

  • Allows evaluation of effective de-airing after MICS procedure, enhancing patient’s safety in regard to air embolism-related problems.

It has been especially valuable in the operating room where it is used preoperatively to confirm or modify anatomical diagnoses which have been established by TTE and angiography and also identifies possible additional pathologic conditions to delineate anatomy and structural details that may have remained ill-defined by transthoracic imaging [23, 24, 25]. The technological advancements, particularly the use of small probe sizes, have significantly improved patient safety and success of cardiac surgery in infants and children [26, 27, 28, 29, 30, 31, 32, 33].

The probe is usually inserted by the anesthesiologist, after induction of general anesthesia, and it is used for all the time of operation with a Philips Sonos IE33 echocardiography machines (Philips, Andover, MA) equipped with pulsed, continuous wave, color Doppler, and 3D capabilities. In patients >20 kg, we have been using an adult probe (xMatrix probe: X7-2t; 3D matrix array probe; 2–7 MHz; Philips, Andover, MA) with 2500 elements per transducer and, on the contrary, in pediatric patients (whose weight is between 4.0 and 20.0 kg), a pediatric probe (Mini Multi probe: S7-3t; 3–7 MHz; Philips, Andover, MA) with 64 elements per transducer and dimensions of 10.7 mm (tip width) and 8.0 mm (tip height).

These clinical benefits, a growing number of highly skilled operators, and improvements in technology have led to the rapid adoption of TEE monitoring in pediatric cardiac surgery with remarkable advances in the management of patients with congenital heart disease in this particular setting.

Anesthesia care

In recent years, “FastTrack” management (FTM), in the perioperative care of patients with CHD, with early tracheal extubation after cardiac surgery, has become increasingly popular [34, 35, 36, 37] especially in MICS, with the delivery of cost-efficient care considered as an additional variable when measuring and comparing surgical outcomes [37, 38].

Potential advantages were previously described [38]:

  1. Reduced incidence of airway irritation and ventilator-associated complications (i.e., accidental extubation, laryngotracheal trauma, pulmonary hypertensive crisis during endotracheal tube suctioning, mucous plugging of endotracheal tubes, barotraumas secondary to positive airway pressure ventilation, and ventilator-associated pulmonary infections and atelectasis)

  2. Reduced parental stress

  3. Reduced requirements of sedation and potential associated hemodynamic compromise

  4. More rapid patient mobilization

  5. Earlier ICU discharge

  6. Decreased length of hospital stay

  7. Reduced costs (ventilator-associated and length of ICU/hospital stay)

In this context, anesthesia should not be managed by a strict protocol. A general institutional approach for children who are candidates to FastTrack extubation consisted of induction of anesthesia with thiopental 5 mg/kg, fentanyl 3 mcg/kg, and rocuronium 0.9 mg/kg. During surgery and cardiopulmonary bypass (CPB), anesthesia is maintained with remifentanil 0.5–1 mcg/kg/min and propofol 3–5 mg/kg. Muscle relaxants are given again before CPB at 0.15 mg/kg. The patient is monitored as routine (ECG, pulse oximetry, invasive arterial pressure, central venous pressure, diuresis, temperature, and somatic and cerebral near-infrared spectroscopy (NIRS)). Shortly before the end of the surgery, remifentanil is discontinued, and intravenous morphine (0.1–0.2 mg/kg) or fentanyl (1–2 mcg/kg) is administered. When surgery is over, according to FTM protocol, the neuromuscular block is reversed by the intravenous administration of atropine, 0.01 mg/kg, and neostigmine, 0.05 mg/kg. Immediate post-extubation analgesia or sedation in children includes a single administration of rectal paracetamol (40–50 mg/kg), a bolus of morphine 0.05 mg/kg iv or fentanyl 0.5–1 mcg/kg iv, and/or midazolam 0.05–1 mg/kg iv, with repeated boluses as needed.

For the first 24 postoperative hours, morphine is given by continuous iv in most patients. Pain scores and vital signs are recorded by the bedside nurse, on an hourly basis throughout the day, or, when appropriate, by the parents or even by the child, if it is old enough to report his/her pain scores on a 0–10 pain scale. Supplemental analgesia is administrated if required, according to the recorded pain scores.

Despite this program, extubation in the OR after pediatric cardiac surgery is to be meditated. In order to migrate to a routine practice of early extubation, it is necessary that surgeons, anesthesiologists, intensivists, perfusionists, and nurses have the same mindset and cooperate to achieve this goal and the final decision. Extubation, either in the operating room or in the ICU, is usually decided based on clinical evaluation and also considering some operative parameters such as bypass and aortic cross-clamp times, the complexity of surgery, requirement of high dosage inotropic support, hemodynamic stability, and occurrence of persistent bleeding. Operating room extubation is usually not performed if there are signs of airway compromise, hemodynamic instability requiring bolus delivery of vasopressors, cardiac rhythm instability, excessive bleeding, or core temperature < 35°C.

In patients submitted to VATS, postoperative pain is significant, especially early after surgery [39, 40], and higher than sternotomy. For these reasons, there has been an increased interest in the use of paravertebral block (PVB). The intercostal nerves are relatively devoid of covering fascia as they traverse the paravertebral space, making it an ideal location for local anesthetic blockade [41]. The PVB technique includes the use of ultrasound [42] with a linear probe at high frequency in pediatric patient with weight > 15 kg, alternatively, which can be performed by a single injection at the level of paravertebral space intraoperatively under direct vision by the surgeon [43] or anesthesiologists prior to chest closure [44]. The single-shot multilevel PVB with ropivacaine 0.5% has a place in these procedures (max 0.4 ml/kg at the fifth intercostal space), with analgesic benefits seen in the first few hours, and can reduce long-term adverse pain outcomes.

In this kind of patients, a change in the attitude of surgeons, anesthesiologists, perfusionists, and nurses, combined with appropriate anesthetic and surgical techniques, permitted better results and outcomes.

Cardiopulmonary bypass and operative strategies

According to our minimally invasive surgical protocol [45], a direct aortic and bicaval cannulation is usually employed in patients with a body weight of less than 10 kg. Since 2006, in larger patients, we have routinely used a peripheral arterial and venous cannulation [46, 47, 48] for establishing the cardiopulmonary bypass (CPB). This is achieved by percutaneous cannulation of the superior vena cava (SVC) followed by surgical isolation and cannulation of the femoral vessels (Figure 1).