Anesthesiology

Pectus repairs

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What the Anesthesiologist Should Know before the Operative Procedure

Pectus excavatum ("funnel chest") is the most common congenital chest wall abnormality in children, with an incidence between 1:300 and 1:500 children and more common in males. These children can develop progressive cardiac and pulmonary abnormalities related to the pectus, necessitating surgery. In addition, pectus excavatum is associated with conditions, like Marfan's Disease and mitral valve prolapse, that can complicate preanesthetic evaluation and preparation, as well as perioperative management.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Pectus excavatum may appear any time between infancy and adolescence. The patient may be asymptomatic, but often presents with some degree of cardiopulmonary abnormalities. The progression of cardiac or pulmonary deterioration may affect timing of surgery. Although some of these patients may have cardiopulmonary impairment, probably the most common reason for the procedure is cosmetic. Children with a pectus excavatum or the less common pectus carinatum ("pigeon breast") are often very self-conscious about the defect and express significant increases in self-esteem after repair.

Repair of congenital pectus excavatum is not an emergent or urgent procedure. However, if significant cardiac or respiratory impairment occurs, the surgeon has to balance the need to prevent further deterioration versus the possibility that the child will continue to grow and the pectus recur. In general, the current practice is to perform the surgery in early adolescence to get a repair that will be adequate, while minimizing the chance of the lesion recurring. Although there is some disagreement in the literature, there is reasonable evidence that both cardiac and pulmonary abnormalities are improved by pectus repair, with greater stroke volume and lung capacity after the repair. Patients report that they fell that their physical status is improved, with less fatigability, chest pain, and shortness of breath after the repair.

2. Preoperative evaluation

The gross appearance of the pectus does not have much of a role in preoperative evaluation. Instead, the focus is on functional status. History is important in identifying functional cardiopulmonary issues. The history should specifically focus on issues such as reduced exercise tolerance or easy fatigability, chest pain, palpitations, recurrent pulmonary infections, difficulty breathing with exertion, and wheezing. Some patients may also express anxiety over the cosmetic appearance of their chest. Physical examination may detect a murmur, wheezing, or limited chest excursion.

Medically unstable conditions warranting further evaluation include a previously undiagnosed murmur. There is a higher incidence of mitral valve prolapse in these patients. If a murmur is detected, further evaluation, usually by echocardiogram, is indicated. If the child has an active pulmonary infection, this should be evaluated and treated. There is a small incidence of pectus in patients with significant medical syndromes. These include Marfan's syndrome (dilated aortic root), celiac disease (poor nutrition), osteogenesis imperfecta (risk of fractures), and spinal muscular atrophy (generalized deterioration of skeletal muscles and respiratory failure). Delaying surgery may be indicated if the child has an active pulmonary infection that has not resolved or has bronchospasm not cleared with bronchodilators. Once these medical conditions are stabilized, surgery can proceed. Most patients with a mitral valve prolapse do not need surgical repair of the heart lesion.

3. What are the implications of co-existing disease on perioperative care?

These patients are usually healthy adolescents who may have cardiopulmonary issues related to the chest wall abnormality. Repair of the lesion will, at least, stabilize these conditions and may improve them. Although there is a reported incidence of pectus with celiac disease and Marfan's disease, these conditions do not normally complicate management of the case. In addition, pectus can occur in conjunction with kyphoscoliosis, adding especially to the pulmonary compromise of the patient.

Perioperative evaluation- Preoperative evaluation focuses primarily on the functional status of the cardiac and pulmonary systems. If the child has other conditions, such as celiac disease or osteogenesis imperfecta, the evaluation is specific to these disease states. With celiac disease, the important consideration is adequate nutrition and hydration. With osteogenesis imperfecta, the important consideration is the risk of fracture with positioning on the operating table and intubation.

Perioperative risk reduction strategies- These children are typically healthy, so that there are not specific risk reduction strategies except for postoperative pulmonary toilet. Preoperative incentive spirometry education at an age-appropriate level can speed recovery and minimize the chance of postoperative atelectasis and pulmonary infection.

b. Cardiovascular system

Acute/unstable conditions: The degree of cardiovascular impairment in these patients is variable. Because the heart is displaced to the left and compressed between the sternum and spine, these patients may have a reduced stroke volume, decreased cardiac output and reserve, arrhythmias. History will help identify those patients with the greatest impairment. An electrocardiogram may show right-axis deviation because of displacement of the heart. An echocardiogram may show reduced stroke volume, as well identify those patients that also have mitral valve prolapse. The degree of mitral valve prolapse will guide the need for prophylaxis for subacute bacterial endocarditis.

The goals of management are to identify which patients will be expected to have a reduced cardiac output perioperatively, which patients have recurring arrhythmias that may complicate the anesthetic course, and which patients need antibiotic prophylaxis for underlying structural heart defects.

c. Pulmonary

Compression of chest contents - Because of the progressive compression of lung contents, there is a decrease in base lung capacity. Some patients may also have recurring pulmonary infections related to poor cough and clearing of secretions. there are standardized scales to evaluate the degree of deformity of the chest wall and compression of the lung contents. The most commonly used is the Haller.

Index, which is the ratio of the horizontal distance of the ribcage (transverse diameter) and the shortest distance between the sternum and vertebrae. This was traditionally measured with a CT scan, but is now commonly done on chest x-rays to minimize radiation exposure. A normal chest has an index of 2.5, while an index of 3.25 or greater is considered severe compression. Pulmonary function tests may also be performed if there is question about the degree of restrictive lung disease or obstructive disease the child has. Probably the most useful information that comes from pulmonary function testing is a determination whether or not the patient needs additional medication to decrease bronchospasm.

Reactive airway disease (Asthma): Asthma is a common finding in children, though it is not proven that there is a higher incidence in these patients. As mentioned above, pulmonary function testing may be prudent if there is a question about how well-controlled their reactive airway disease is currently.

Pulmonary infections - If there is any evidence of ongoing pulmonary infections, these should be cleared with antibiotics and chest physiotherapy before proceeding with this elective surgery.

d. Renal-GI:

These patients do not typically have renal disease. Patients with celiac disease have about a 1% incidence of pectus, but the incidence does not seem related to the severity of the celiac disease.

e. Neurologic:

These patients do not typically have neurologic disease.

f. Endocrine:

These patients do not typically have endocrine disease.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

If the patient is receiving medications for control of reactive airway disease, they should be continued until the day of surgery. There are no other medications that these patients would likely be receiving based on the pectus.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Reactive airway disease - continue as before surgery

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac - continue with administration on the morning of the procedure

Pulmonary - If the patient is on chronic medication for bronchospasm, those medications should be continued. If the patient has moderate or severe bronchospasm, they should receive three days of oral prednisoneprior to the procedure. If they take daily or frequent doses from a metered dose inhaler, such as albuterol, they would benefit from a normal "puff" before induction.

Renal - not typically an issue

Neurologic - not typically an issue

Anti-platelet- not typically an issue

Psychiatric- not typically an issue

j. How To modify care for patients with known allergies -

There are no specific issues related to allergies that would influence care for this surgery except as it relates to a known allergy to anesthetic drugs, antibiotics, or blood products

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

N/A

l. Does the patient have any antibiotic allergies? (common antibiotic allergies and alternative antibiotics)

Known allergies to the penicillins and cephalosporings are the most commonly seen antibiotic allergies in pediatric surgical patients. Clindamycin is the most commonly used

substitute in patients with known allergies.

m. Does the patient have a history of allergy to anesthesia?

When the family gives a history of allergy to anesthesia either in the patient or relative, it is important to get a detailed history of the event. True allergy to anesthetic agents in children is very rare.

Malignant hyperthermia:

  1. Documented- avoid all trigger agents such as succinylcholine and inhalational agents:

    1. Proposed general anesthetic plan:

    2. Insure MH cart available:

      [- MH protocol]

  2. Family history of MH: Determine exact relationship with suspected or known episode in family member. Obtain actual records of past event if possible. Consider MHS precautions if exact relationship and nature of event do not clearly rule out MHS

  3. Local anesthetics/ muscle relaxants: As with all possible allergic events, determine as detailed a history of the event as possible and obtain hospital records, if available. If the episode is possibly a true allergic reaction, consider avoiding that class of drug.

5. What laboratory tests should be obtained and has everything been reviewed?

There is no blood work that is mandatory for these cases with the exception of a type and cross for blood. Especially with a Nuss procedure, type and cross units of blood should be available.

  1. Hemoglobin levels: Hemoglobin levels are not obtained for otherwise healthy children

  2. Electrolytes: Electrolyte levels are not obtained for otherwise healthy children

  3. Coagulation panel: Coagulation studies are not obtained for otherwise healthy children.

  4. Imaging: At a minimum, the patient will have a chest xr-ay. The chest x-ray in these patients will occasionally show an opacity in the right lung field secondary to compression of lung tissue that can be mistaken for an infiltrate, but does not represent active disease. The patient may also have had a CT of the chest. Both studies should be inspected for evidence of active infection

  5. Other tests: Pulmonary function tests, if obtained, should be reviewed to ensure extra attention to bronchodilator medication is not needed. The electrocardiogram should be reviewed and any unexpected abnormalities discussed with a cardiologist.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

These procedures are almost always conducted under general anesthesia. Although it is theoretically possible to combine a variety of regional anesthetic techniques for the case, it is not practical. There is some variability in the anesthetic technique related to which of the two surgical approaches are used for the case. With all surgical repairs, the anesthetic technique is based on general endotracheal anesthesia. There are no specific indications or contraindications for specific drugs or approaches for the anesthetic itself. The variability in technique is based primarily on the degree and nature of postoperative pain in the patients.

The Ravitch procedure and its variants are the classical approach to pectus repair. The sternum is approached through a skin incision in front, sternocostal cartilages are removed, and the lower sternum is mobilized and reshaped. A stabilizing bar is inserted under the sternum and will stay in place 6-9 months. This thoracotomy is associated with moderate postoperative pain in anterior midline. Consequently, intraoperative analgesia with opioids and opioids for postoperative pain management are most commonly used and appropriate for the procedure.

The Nuss procedure, a newer approach, is a minimally invasive technique using thoracoscopy. Under direct vision through a thorascope, a transmediastinal tunnel behind the sternum, and a curved metal bar is passed behind the sternum with the apex of the curve pointing posteriorly. The bar is rotated 180 degrees, elevating the depressed sternum. An advantage to this technique is preservation of the sternocostal cartilages. However, there is a sudden dramatic change in the chest wall configuration that is associated with significantly greater postoperative pain than after a Ravitch procedure. The pain is not only in the sternal area, but also along the lateral and posterior thoracic cage. This probably represents pain from the stretching or tearing of muscle fibers with the sudden change in configuration of the entire chest wall. Because of this different pain profile, many centers have adopted the use of a thoracic epidural catheter inserted before induction to provide focused postoperative pain relief. Other centers rely on either opioids or paravertebral nerve blocks for postoperative pain management.

a. Regional anesthesia - Used as part of a balanced anesthetic

Neuraxial

Benefits include a smooth emergence and excellent postoperative pain relief, especially after a Nuss procedure.

Drawbacks include lack of experience of placing epidural catheters in pediatric patients for some practitioners, a slight delay in starting the case, and the need to have postoperative care givers and settings that are suitable for the use and monitoring of children with epidural catheters and infusions. Many practitioners have little familiarity with inserting thoracic catheters in children and are, therefore, not comfortable with their use.

Issues, besides familiarity with neuraxial blockade in children, are primarily related to placement of the catheter and postoperative choice of drugs and infusion characteristics. Although some practitioners have successfully used catheters inserted at either the lumbar or even caudal level for these procedures, the success rate is not high. A thoracic catheter is consistently placed at the appropriate level. Most adolescent patients will tolerate the procedure awake with sedation, but younger children may not be able to cooperate adequately. Several groups have reported successful insertion of epidural catheters, including thoracic catheters, in anesthetized children without complication. Both fentanyl and fentanyl/bupivacaine infusions have been used successfully.

Peripheral Nerve Blocks, in particular intercostal blocks, can be used in this setting, but do not give the long-lasting benefit of other approaches. They are most useful in providing pain relief for short periods of time, especially in the immediate postoperative period. There is some work using paravertebral nerve blocks for postoperative pain, but there is not much in published experience with this to evaluate its relative efficacy.

b. General Anesthesia

The benefits of general anesthesia are the same as for any intrathoracic procedure. These include control of the airway, ability to reliably administer enriched oxygen mixtures, ability to suction the airway, and the ability to reverse atelectasis with positive pressure and controlled ventilation.

Drawbacks are the same as for any intrathoracic procedure. These include the potential for airway trauma, barotrauma, and drug overdose. There is nothing unique to this procedure or these patients that is different than other children having a thoracotomy.

Airway concerns arise from the surgical procedure itself. Lung isolation is not a concern, so the use of a double lumen tube is not needed. However, there is always a concern that surgical manipulation can cause pneumothorax atelectasis, or direct lung injury.

c. Monitored Anesthesia Care

  1. Monitored anesthesia care is not appropriate for this procedure

6. What is the author's preferred method of anesthesia technique and why?

What prophylactic antibiotics should be administered? - Antibiotics should be given at the appropriate interval, less than hour, before skin incision.

What do I need to know about the surgical technique to optimize my anesthetic care? - General endotracheal anesthesia is the preferred method of anesthetic management. Although there can be some compression of lung tissue with either approach, nitrous oxide is not contraindicated. Consequently, a wide variety of drugs and techniques can be used with no demonstrated superiority over another. It is my preference to use a volatile agent-based technique with nitrous oxide and opioids unless there are specific contraindications based on other patient factors. Because both surgical approaches are either in the midline or involve tunneling symmetrically across the chest, there is no need for a double lumen tube. The surgical approach does alter the anesthetic technique in terms of intraoperative and postoperative pain management, with a thoracic epidural or paravertebral blocks considered for patients undergoing a Nuss procedure.

What can I do intraoperatively to assist the surgeon and optimize patient care? These are not complicated cases with special needs for changes in anesthetic technique. A double lumen tube will not enhance surgical conditions noticeably.

However, in the Nuss procedure, there may be a short period of time during the passing of the sternal bar where more shallow breaths may create a quieter field for the surgeon.

What are the most common intraoperative complications and how can they be avoided/treated? Most intraoperative complications are rare and surgical in nature, though the anesthesiologist will often have an important role in stabilizing the patient while the complication is addressed by the surgeon. There have been rare instances with the Nuss procedure where passing of the sternal bar has resulted in myocardial perforation. This is a dramatic event that must be addressed aggressively with immediate opening of the chest and control of bleeding or even institution of supportive cardiopulmonary bypass. Fortunately, this has occurred very few times. Other rare surgical complications associated with the Nuss procedure have included diaphragmatic perforation, subcutaneous emphysema, and dislocation of the stabilizing bar. With both the Nuss and Ravitch procedures, intraoperative atelectasis from compression of lung tissue can lead to intraoperative hypoxemia. Reexpansion of the lung and PEEP usually quickly reverses the condition, though suctioning of the endotracheal tube may also be needed to remove secretions.

Cardiac complications- There is always the possibility of direct injury to the heart, either during the open Ravitch technique or the thoracoscopic Nuss procedure.

Pulmonary complications- There is a possibility of a symptomatic pneumothorax with either the open Ravitch technique of the thoracoscopic Nuss procedure. Direct injury to the lung itself is unlikely, though possible. With the Ravitch procedure, postoperative complications have included flail chest and postoperative atelectasis. Blood loss is minimal to moderate. With the Nuss procedure, postoperative complications have included atelectasis, subcutaneous emphysema, myocardial perforations, diaphragmatic perforation, and pericardial and pleural effusions.

Neurologic complications: Whenever neuraxial regional techniques are used, there is always the potential for direct or indirect nerve injury.

a. Neurologic

There has been some recent (unpublished) concern about unexpected spinal cord injury in patients undergoing the Nuss procedure. The exact cause, related possibly to sudden deformation of the thoracic cage with turning of the sternal stabilizing bar or the use of a thoracic epidural catheter, is not known and subject to extensive speculation. This has led some centers to use different modalities of analgesia than the thoracic epidural catheter for postoperative analgesia for these patients, while other centers continue to use the modality. Some attention has also been focused on maintaining normal intraoperative blood pressures, especially when an epidural catheter is used, to ensure that there is adequate perfusion of, in particular, the spinal cord.

b. If the patient is intubated, are there any special criteria for extubation?

These patients are usually extubated without problem at the end of the procedure unless they have other medical issues that complicate the decision.

c. Postoperative management

What analgesic modalities can I implement? Most patients who undergo a Ravitch repair get good pain relief from opioids. It is our practice to use patient controlled analgesia as the preferred method, with dilaudid or morphine as the opioid. We start with demand-only, but add a background infusion if needed. Intercostal nerve blocks can be used at the end of the procedure for the immediate postoperative period to supplement the opioids. For patients who have a Nuss procedure, the choice of analgesic methods is more complicated. Because of the concern about potential spinal cord hypoperfusion, at least one center has stopped using thoracic epidural analgesis intraoperatively and postoperatively. Because patients who have had the Nuss procedure have extensive postoperative pain in the lateral and posterior chest walls, as well as the sternal region, parenteral opioids may not give optimal pain relief, especially in the first 24 hours postoperatively. Paravertebral nerve blocks may offer significant help in the first hours postoperatively. Consequently, our approach to analgesia in children undergoing a Nuss procedure starts with a conversation with our surgical colleagues about the controversy surrounding thoracic epidural analgesia. If both the surgical and anesthesiology staff conclude that thoracic epidural analgesia is desirable, the risks and benefits are discussed with the family and, as appropriate, the patient. If any involved are uncomfortable with the epidural approach, we use opioids in the case, continuing with PCA in the postoperative period. If we do use a thoracic epidural catheter, we will use a constant infusion in younger children and patient controlled patient analgesia in older children. In some patients with thoracic epidural catheters, breakthrough pain is treated with a supplemental, demand-only PCA.

What level bed acuity is appropriate? These patients normally are admitted to a general floor for postoperative care. If there are medical issues that require critical care monitoring or if there is a serious complication, then the patient will recover in a critical care unit.

What are common postoperative complications, and ways to prevent and treat them? The most common postoperative complication is atelectasis. Aggressive preoperative education about pulmonary toilet maneuvers and encouragement of incentive spirometry and coughing usually will minimize this complication. Pain is probably the second most common postoperative complication and requires close attention to ensure both baseline and rescue protocols. Pneumothorax is an occasional postoperative complication that may require drainage if compromising either ventilation or oxygenation.

What's the Evidence?

Castellani, C, Windhaber, J, Schober, PH, Hoellwarth, ME. "Exercise performance testing in patients with pectus excavatum before and after Nuss procedure". Pediatr Surg Int. vol. 26. 2010. pp. 659-63.

Frantz, FW. "Indications and guidelines for pectus excavatum repair". Curr Opin Pediatr. vol. 23. 2011. pp. 486-91.

Jaroszewski, D, Notrica, D, McMahon, L, Steidley, DE, Deschamps, C. "Current management of pectus excavatum: a review and update of therapy and treatment recommendations". J Am Board Fam Med. vol. 23. 2010. pp. 230-9.

Kelly, RE, Cash, TF, Shamberger, RC, Mitchell, KK, Mellins, RB, Lawson, ML, Oldham, K, Azizkhan, RG, Hebra, AV, Nuss, D, Goretsky, MJ, Sharp, RJ, Holcomb, GW, Shim, WK, Megison, SM, Moss, RL, Fecteau, AH, Colombani, PM, Bagley, T, Quinn, A, Moskowitz, AB. "Surgical repair of pectus excavatum markedly improves body image and perceived ability for physical activity: multicenter study". Pediatrics. vol. 122. 2008. pp. 1218-22.

Koumbourlis, AC. "Pectus excavatum: pathophysiology and clinical characteristics". Paediatr Respir Rev. vol. 10. 2009. pp. 3-6.

Krueger, T, Chassot, PG, Christodoulou, M, Cheng, C, Ris, HB, Magnusson, L. "Cardiac function assessed by transesophageal echocardiography during pectus excavatum repair". Ann Thorac Surg. vol. 89. 2010. pp. 240-3.

Hammer, G, Hall, SC, Davis, PJ, Motoyama, EK, Davis, PJ. "Anesthesia for General Abdominal, Thoracic, Urologic and Bariatric Surgery". SMITH'S ANESTHESIA FOR INFANTS AND CHILDREN. C.V. Mosby. 2011. pp. 745-785.

Birmingham, PK, Wheeler, M, Suresh, S, Dsida, RM, Rae, BR, Obrecht, J, Andreoni, VA, Hall, SC, Cote, CJ. "Patient-controlled epidural analgesia in children: can they do it?". Anesth Analg. vol. 96. 2003. pp. 686-91.

Soliman, IE, Apuya, JS, Fertal, KM, Simpson, PM, Tobias, JD. "Intravenous versus epidural analgesia after surgical repair of pectus excavatum". Am J Ther. vol. 16. 2009. pp. 398-403.

Weber, T, Mätzl, J, Rokitansky, A, Klimscha, W, Neumann, K, Deusch, E. "Medical Research Society. Superior postoperative pain relief with thoracic epidural analgesia versus intravenous patient-controlled analgesia after minimally invasive pectus excavatum repair". J Thorac Cardiovasc Surg. vol. 134. 2007. pp. 865-70.

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