Discussion
Preoperative evaluation and Hand-Off report
Critically ill pediatric patients often need anesthesia for various reasons. These patients have multiple organ dysfunction and complex medical problems and it is important for pediatric anesthesiologists to have a thorough preoperative assessment of the patient, no matter what the type of surgery is. However, in busy tertiary care centers, where minor procedures are commonly added to the OR schedule, this can present as a challenge. Although having electronic medical records allow an anesthesiologist to easily review patient information, critical details can be missed, especially for patients who have been in the ICU for a long period of time. The CT scan finding of lobar emphysema was completely missed in the preoperative evaluation. Having a standardized hand-off is essential to communicate important patient data during transfer of patient care. Communication failure is one of the greatest barriers in giving an effective handoff.1 It is thereby imperative that the providers actively communicate pertinent patient details during patient handoff to ensure nothing is lost during the transition.2 This successful transfer of information can be essential to reducing medical errors and providing quality patient care. Given the patient’s complicated medical history, receiving a quality handoff from the PICU provider to the attending anesthesiologist could have improved the physician’s understanding of the patient’s medical condition. This would also help the physician provider plan in advance and be more prepared for the adverse events that could occur during transport of the critically ill patient as well as throughout the perioperative period.
High Peak Airway Pressure in a Hemodynamically Unstable Patient
One of the common intraoperative events that anesthesiologists encounter in the operating room is high peak airway pressure and desaturation. It is important to recognize and treat the cause of this event early because increased peak airway pressures may lead to barotrauma and volutrauma which may result in pneumothorax, pneumomediastinum and acute lung injury. In addition, increased intrathoracic pressure may also result in hemodynamic consequences such as hypotension secondary to decreased venous return. This is particularly important for pediatric patients who are dependent on preload for their cardiac output. At worst, if untreated immediately, it may lead to bradycardia and potentially, cardiac arrest as what happened to our patient. The list of differential diagnosis is long and having a systematic way of ruling out each cause can be helpful in quickly solving the problem and preventing its complications. The most significant of these are tension pneumothorax and severe auto-positive end expiratory pressure (auto-PEEP). Both can lead to marked hypotension because of decreased cardiac output and marked hypoxia from ventilation and perfusion mismatch.3
There are three major components that should be assessed in a patient who is presenting with high peak airway pressures and desaturation: the anesthesia machine and/or circuit, the patient and the endotracheal tube. Disconnect the patient from the ventilator and manually ventilate the patient with 100% FiO2. If the patient is difficult to ventilate upon disconnection, the problem is not in the circuit or the ventilator, rather, the patient or the endotracheal tube. If a rush of air is heard upon disconnection and the patient becomes hemodynamically stable, then ventilator-induced auto-PEEP is the cause. If the patient doesn’t improve, look for unequal chest rise, listen for air leak and unequal breath sounds and feel for any resistance in bagging. Endotracheal tube migration is common in pediatric patients especially with small movements of the head and neck. Assess the position of the endotracheal tube by direct laryngoscopy, or if time permits, use a fiber optic bronchoscope. If the patient has bilateral breath sounds, pass a suction catheter to rule out a kinked endotracheal tube. If the catheter is able to pass, suction the patient for any possible mucus plug.
If the patient fails to improve despite doing the above, a more detailed review of the patient’s history and a more focused physical examination may aid in determining the cause. It is important to always associate the patient’s disease and co-morbidities with the situation at hand. Depending on the urgency of the situation, imaging studies may be done to help in diagnosis.
Diagnosis and Management of Congenital Lobar Emphysema
Congenital lobar emphysema (CLE) is a rare congenital anomaly characterized by overdistention of an otherwise normal lobe of the lung that compresses adjacent normal lung units and leads to atelectasis.4 The affected bronchus allows passage of air on inspiration but limits expulsion of air on exhalation, which leads to air trapping and lobar air expansion. If this process continues, it can cause a mediastinal shift, which can decrease venous return, decreased cardiac output and ventilation-perfusion abnormalities resulting to hypotension and hypoxia.5
Pathologic causes include bronchial collapse secondary to bronchial cartilage dysplasia, or bronchial obstruction due to redundant mucosal folds or septum, mucous plugs or extrinsic compression from abnormal vasculature.6 The most frequent site of involvement is the left upper lobe, occurring in 40-50% of the cases.
CLE is commonly confused with tension pneumothorax as both diseases present with unilateral decreased breath sounds and hemodynamic instability. As in our case, misdiagnosis may prompt the caregiver to do needle decompression and cause iatrogenic pneumothorax, which may further deteriorate a child’s condition. If this diagnosis was known early on, CLE could have been considered highly in the differential diagnoses and patient could have been managed differently.
CLE is initially diagnosed with a chest radiograph and computerized tomography scan.
Fluoroscopy helps establish diagnosis. In an obstructive emphysema, fluoroscopy shows ipsilateral mediastinal shift on inspiration and contralateral shift on expiration. Additionally, there is poor diaphragmatic movement and lack of volume change on the affected side during respiration.7
The treatment of congenital lobar emphysema with serious symptoms is lobectomy.8 If the patient has severe cardiovascular compromise, it is considered as a surgical emergency and only a thoracotomy could relieve the ventilatory and mediastinal compression from the expanding emphysematous lobe. Conservative management maybe done in older children with mild to moderate symptoms with a close follow up of the patient. 8
In the anesthetic management of these patients, inhalational induction is preferred and spontaneous ventilation is maintained until the chest is opened.9 Nitrous oxide is contraindicated. Gentle manual ventilation may be needed during induction, keeping the airway pressure below 20-25 mmHg to avoid over distention of the affected lobe. Intravenous ketamine for intraoperative analgesia are preferred over opioids because of the benefit of maintaining spontaneous ventilation and preventing further hemodynamic instability.
Cognitive Errors and Biases in Medical Decision Making
Cognitive errors are common and contribute significantly to delayed or incorrect diagnoses.10 In emergency situations, physicians are under pressure to make rapid critical decisions based on the limited information available. Their most immediate goal is to stabilize the patient for recovery. The risks of errors regarding patient care increases in the event that time limits the physician’s ability to review the past records of a patient. In this case, the physician was required to make a decision based on the patient’s current clinical manifestations and intraoperative radiologic findings. While the fluoroscopy findings revealed hyperlucency in the left thorax, which supported the diagnosis of a tension pneumothorax, past medical history would have supported that this was finding associated with her lobar emphysema. Given the acuity of the situation, other probable diagnoses were not taken into consideration and the anesthesiologist performed a needle decompression. This decision was influenced by availability bias (diagnosing based on an easily remembered or previously encountered event) and confirmation bias (the tendency to seek information that supports a diagnosis while disregarding information that is not consistent with the diagnosis). An error in decision happened because the physician was not aware of critical information that was required to provide the correct care. There are no clear strategies to avoid cognitive errors but cognitive self-monitoring strategies, use of clinical aids, counterbalancing heuristics with decision time-out maybe helpful.10