Providing Anesthesia for Patients With Congenital Lung Lesions
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Published on in In Utero Insights
The role of the anesthesiologist is to maintain patient safety and comfort while facilitating the planned surgical procedure. Many puzzle pieces interact and influence the anesthetic plan, or “prescription.” A small selection of items which become the puzzle pieces include the age and weight of the patient; the surgeon and their surgical approach (e.g., open thoracotomy vs. thoracoscopy); family history of anesthetic issues (such as malignant hyperthermia); the physiologic compromise caused by the lung lesion itself; and the physiologic derangement that occurs during the surgery itself. The anesthesiologist must fit many pieces together to come up with a sound anesthetic prescription, which includes management of the patient’s airway, ventilation strategies to avoid further lung injury, fluid and possible blood administration, and postoperative analgesia.
Depending on the degree of compromise to the developing fetus or child, surgical interventions may occur at various times. Some cases may require intervention while the fetus is still developing. In these situations, an experienced anesthesia team cares for both the mother and the fetus simultaneously. Minimally invasive procedures may require light maternal sedation, but open-fetal surgery, which may take place in the middle of gestation or near term, is a complex undertaking.1
Anesthesia for open mid-gestation procedures or near-term EXIT procedures involves deep general anesthesia for the mother. The anesthesia for open-fetal surgery is about twice as deep as anesthesia for normal surgery. This serves to anesthetize the mother, to anesthetize the fetus, and to ensure adequate uterine relaxation for the operation. Hypotension and maternal pulmonary edema are known complications of these procedures. The anesthesiologist must balance these competing needs with meticulous fluid and blood pressure management, while preparing for possible (albeit quite rare) rapid maternal blood loss, and providing post-operative maternal analgesia with an epidural. During these cases, the fetus is also carefully monitored and anesthetized, and the fetus may receive fluids, blood and other medications for anesthesia and resuscitation.
The ability of a fetus to feel pain is a subject that will require continued study. What is clear, however, is that a fetus will demonstrate a stress response to surgical stimulation, stress responses are associated with poorer outcomes in premature infants, and these stress responses are attenuated with opioids. Our current strategy with opioid management in fetal surgery results in blood concentrations of opioids that are comparable to those of neonates undergoing major surgery in the postnatal period.2
Most children diagnosed with lung lesions do not require fetal intervention or immediate surgery at the time of delivery. These children will undergo surgery a few days to several weeks after birth.
The anesthesiologist must be comfortable taking care of neonates and small babies, with all of their attendant concerns. Some issues include peaceful induction of anesthesia, skillful intubation, careful glucose control, and familiarity with still maturing organ systems. Some surgical techniques require advanced management of ventilation, such as ventilating only one lung while the diseased lung is intentionally collapsed and made still to optimize surgical exposure.3 The vast majority of patients are extubated in the operating room and recover in the neonatal intensive care unit for two to three days.
Postoperative analgesia may be quite a challenge for these patients. A comfortable child will have a better recovery, and a comfortable child will also help allay family anxiety. After thoracotomy, pain is often managed with a catheter, which is introduced into the epidural space via the sacrococcygeal ligament. The epidural catheter tip is advanced up to the thoracic vertebrae to cover the dermatomes involved in the incision. The epidural medications are chosen to maximize analgesia while minimizing side effects.4 A special team of doctors and advanced practice nurses follows children with epidurals to come up with patient-specific plans to manage their pain and to help transition these children to intravenous and oral analgesics.
Surgical care for these patients is challenging as there are many variables that can change at any time: tumors may suddenly increase in size in the prenatal period, bradycardia may occur during an open-fetal surgery, hypoxia may occur during a postnatal pulmonary lobectomy, or pain relief may become inadequate in the intensive care unit. The anesthesia team at CHOP is uniquely suited to care for these patients in all these stages. The surgical volume at CHOP is extraordinarily high by any standard, and high volume often makes for safer, more efficient care systems. To concentrate the anesthetic expertise, subsets of anesthesiologists within the department focus their care on certain patient populations (e.g., cardiac, neurosurgical, fetal, thoracic, craniofacial and orthopedic). This strategy further leverages the anesthesiologist’s knowledge base and technical skills. We understand and can anticipate the changes that may occur, we know how these changes will impact the anesthesia plan, and we have the skills to safely and quickly respond.
1. Anesthesia for fetal surgery. Lin EE, Tran KM. Semin Pediatr Surg. 2013;22(1):50–55.
2. Quantification of serum fentanyl concentrations from umbilical cord blood during ex utero intrapartum therapy. Tran KM, Maxwell LG, Cohen DE, Adamson PC, Moll V, Kurth CD, Galinkin JL. Anesth Analg. 2012;114(6):1265-1267.
3. Fluoroscopic-assisted endobronchial intubation for single-lung ventilation in infants. Cohen DE, McCloskey JJ, Motas D, Archer J, Flake AW. Pediatr Anaesth. 2011;21(6):681–684.
4. Efficacy of addition of fentanyl to epidural bupivacaine on postoperative analgesia after thoracotomy for lung resection in infants. Ganesh A, Adzick NS, Foster T, Cucchiaro G. Anesthesiology. 2008;109(5):890–894.
Contributed by: Kha Tran, MD
Categories: In Utero Insights Winter 2014