key: cord-0953177-d5u6n939
authors: Niermeyer, Weston L.; Ball, Jessica; Worobetz, Noah; Bourgeois, Tran; Onwuka, Amanda; Burrier, Candice; Chiang, Tendy
title: Respiratory viral panels and pediatric airway evaluation: the role of testing for upper respiratory infections to stratify perioperative risk
date: 2020-04-21
journal: Int J Pediatr Otorhinolaryngol
DOI: 10.1016/j.ijporl.2020.110057
sha: c6b0daaa78cd0437943c7d74214defdc73aeb728
doc_id: 953177
cord_uid: d5u6n939

Abstract Objectives Children admitted with stridor and respiratory distress comprise a complex patient group that requires the otolaryngologist to decide when to assess and intervene with direct laryngoscopy and bronchoscopy (DLB). Historically, the diagnosis of viral upper respiratory tract infection (URTI) can lead to postponement of surgery due to concerns of perioperative complications related to acute illness. Respiratory viral panels (RVP) are often used to confirm the presence of recent or active viral infection and can affect the differential diagnosis of upper airway obstruction. This study examined whether RVP positive testing is correlated with perioperative complications and operative findings in pediatric patients undergoing inpatient DLB. Methods A retrospective chart review of 132 pediatric patient encounters was performed. Viral testing results, DLB indication, DLB findings, and perioperative complications were compared. Results Sixty encounters (45.5%) involved a positive RVP, and 72 (54.5%) involved a negative RVP. Those with positive RVP were less likely to have an anatomic airway abnormality (p = 0.0250) and more likely to have a history of recurrent upper respiratory infections (p = 0.0464). The most common reason for DLB was to assess for structural airway abnormality. Laryngospasm occurred in 1 (1.7%) RVP positive and 1 (1.4%) RVP negative encounter, and 2 (2.8%) RVP negative encounters required reintubation. No other major complications were observed. No association was noted between RVP results and incidence of major or minor complication. Conclusions Major perioperative complications after surgical intervention with DLB for the management of complex, inpatient children with stridor and respiratory distress are rare. RVP positivity, specific pathogens identified on RVP, and presence of URI symptoms were not associated with perioperative complications.

Inpatient evaluation of children with stridor often involves surgical intervention with direct laryngoscopy and bronchoscopy (DLB) to assess for the presence of subglottic and lower airway pathology. In addition to stridor, obstruction may manifest as difficulty to extubate or acute respiratory distress. These signs are often due to fixed airway lesions, inflammatory or infectious processes or a combination of both. Because patients can have a complex presentation, acute decompensation or increased work of breathing can be suggestive of not only laryngotracheal pathology but also underlying upper respiratory tract infection (URTI). The presence of a URTI has been shown to increase perioperative morbidity and may in turn increase the risk of DLB [1, 2] . As pediatric otolaryngologists, we are faced with the decision to proceed with surgical intervention or postpone until the resolution of URTI symptoms. However, the safety of DLB in acutely ill pediatric patients is not well described.

Respiratory virus testing is available to objectively assess for URTI in children [3] . Respiratory viral panels (RVP) are easily administered by nasopharyngeal swabs and are most commonly used to differentiate between viral and bacterial infections, thus impacting clinical decision making. In the inpatient setting, positive viral testing may steer management by influencing the timing of anesthesia clearance and surgical intervention. In this study, a cohort of pediatric patients undergoing inpatient assessment for acute respiratory symptoms with recent history of RVP testing were examined retrospectively with the hypothesis that a positive RVP does not increase perioperative complications in children undergoing DLB.

A retrospective cohort study was conducted at a single pediatric tertiary hospital system to evaluate outcomes of patients who underwent a surgical airway procedure and had been assessed with RVP. Inclusion criteria consisted of patients aged 0 to 18 at the time of admission between January 2014 and December 2018 having underwent laryngoscopy or bronchoscopy (current procedural terminology (CPT) 31526 and 31622) and having received an RVP within 6 weeks prior to surgery. The study was approved by the Nationwide Children's Hospital Institutional Review Board.

Patients were excluded if they had one or more of the following: hospital admission within 10 days of birth, lack of bronchoscopy under anesthesia, non-otolaryngology surgery performed in the same case (combination cases with other services), tracheostomy performed in the same case, tracheostomy dependence, and extensive, non-airway, otolaryngology procedures performed in the same case. These exclusion criteria were necessary in order to eliminate complications related to other comorbid conditions or procedures. Medical records for all remaining patients were reviewed for perioperative events and operative details including surgical indications and intraoperative findings.

Demographic information, comorbidities, dates and results of RVP tests, dates of DLB, and viral prodrome symptoms were extracted from medical records. Indications for DLB were identified within the surgical note and classified as structural concern, clinical concern, infection, bleeding, and suspected foreign body/aspiration. Structural concerns included patients presenting with stridor and dysphonia, and patients diagnosed with stenosis, malacia, vocal cord paralysis, and obstruction on preoperative flexible laryngoscopy. Clinical concern represented patients who had respiratory distress or respiratory insufficiency with subsequent DLB based on the surgeon's judgment.

Patients were treated by a group of ten pediatric otolaryngologists. Perioperative management was performed according to standard of care. While there was potential for some variation in technique from case to case, standard DLB for the group included the use of topical lidocaine, exposure with a Parsons laryngoscope and visualization of the larynx and trachea with rod lens telescope and ventilating bronchoscope. Airway pathologies identified on DLB were characterized by type and location: supraglottis, glottis, subglottis, trachea, and bronchi.

Additional endoscopic surgical interventions performed alongside of DLB were recorded.

Symptom-based URTI infection diagnosis was made when a patient exhibited a minimum of 2 URTI symptoms (rhinorrhea, sore throat, sneezing, nasal congestion, malaise, cough, or fever greater than 38ºC) [4] . Statistical analyses were conducted with unique encounters rather than unique patients, as there were four patients each with two eligible encounters. RVP closest to surgical intervention were used in encounters with more than one RVP in the six-week time period. Categorical patient characteristics were reported as frequencies and proportions while continuous variables were reported as medians and interquartile ranges. Chi square and Fisher's exact tests were used to test for association between categorical variables and Wilcoxon two sample tests were used for continuous variables. Tests for association were carried out comparing RVP results (positive or negative) with patient characteristics, airway pathologies, perioperative major and minor complications, and viral prodrome. Tests for association were also carried out looking at the association of perioperative major and minor complications to individual virus type and viral prodrome. The relationship between RVP and perioperative complications was evaluated for the entire cohort as well as subgroups of the population based on the number of weeks prior to DLB that an RVP was performed. Findings were determined to be significant at p < 0.05. All statistical tests were conducted on SAS Enterprise version 7.15.

A total of 132 encounters were observed in this cohort. There were 72 RVP-negative (54.5%) and 60 RVP-positive (45.5%) encounters. Median patient age at intervention was 0.7 years (IQR: 0.2-2.8). Median hospital length of stay was 11 days (IQR: 5.0-33.5). Baseline characteristics and association with RVP results are listed in Table 1 . Patients with positive RVP were less likely to have history of known structural airway anomaly (p = 0.03) and more likely to have history of recurrent upper respiratory infections (p = 0.05). No other association between patient characteristics and RVP results were noted. Seventy-four percent of all encounters were characterized as ASA class III or IV indicating a high-risk population; no association with positive RVP results was found, however. The most common reason for DLB was to assess for structural airway abnormality, followed by airway assessment due to clinical concern (Table 2).

The most common viral pathogens discovered in RVP positive encounters were Rhinovirus/Enterovirus (29, 22.0%), Respiratory Syncytial Virus (7, 5.3%), and Human Metapneumovirus (5, 3.8%) ( Table 3) .

Structural airway anomalies on DLB were diagnosed in 77.3% of encounters with no difference between RVP negative encounters (59, 81.9%) compared to RVP positive encounters (43, 71.7%) ( Table 2 ). Structural airway anomalies were most often found in the subglottis among RVP positive encounters (23, 38.3%) and the supraglottis among RVP negative encounters (26, 36.1%). Fifteen percent of encounters had abnormalities at multiple levels of the airway. Nearly one third of encounters (25% RVP positive and 31.9% RVP negative) required an endoscopic intervention to address the airway pathology seen on DLB. These interventions included supraglottoplasty, foreign body removal, injection laryngoplasty, and excision of a mass, cyst, or granulation tissue.

Four (3.0%) encounters had major airway complications reported by anesthesia (Table 4 ). Major complications included laryngospasm (1 (1.7%) RVP positive, 1 (1.4%) RVP negative) and need for reintubation (2 (2.8%) RVP negative). There were no bronchospasms, emergent tracheostomies, cardiac arrests, or mortalities. These major airway complications all occurred in patients who were younger than one year of age. No association was noted between prevalence of major complication and RVP results (p = 0.63). Oxygen desaturation below 90% was the most common complication (63, 47.7%), but an association between prevalence of oxygen desaturation and RVP result was not observed. Thirty-six (27.3%) encounters required an increase in respiratory management postoperatively compared to preoperatively. No significant association was observed, however, between escalated respiratory support and RVP results (p = 0.8028). In addition, no association was observed between specific type of virus or presence of multiple viruses and surgical complications (Table 3) .

Overall, RVP testing was most often performed within 1 week of operative intervention (RVP positive (39, 44.3%) and negative (49, 55.7%)) ( Figure 1 ). The proportion of observed complications appears to increase among RVP positive encounters as time interval between date of bronchoscopy and date of RVP decreased. Among positive RVP encounters obtained within a week of DLB, the complication rate (69%) was not different from encounters with negative RVP (65%). No association was observed between RVP result and number of complications when time interval was restriction to within 1 week.

To address potential effect modification of RVP by virus stage (active URI symptoms vs. asymptomatic viral shedding), we performed an analysis comparing perioperative complications using symptom-based URTI diagnosis compared to RVP-based URTI diagnosis. Among the 27 (20.5%) encounters that exhibited criteria for symptom-based diagnoses, 15 (25.0%) were RVP positive compared to 12 (16.7%) that were RVP negative (Table 5) . No association was observed between symptom-based and RVP-based URTI diagnosis, nor was an association seen between symptom-based URTI diagnosis and major or minor complications.

Pediatric otolaryngologists are often consulted to evaluate hospitalized children with acute airway symptoms. Presentations can vary, ranging from failure to extubate to stridor and respiratory distress. Acute processes can arise from infectious processes and can mimic static airway lesions. In clinically complex scenarios, our institution uses rapid viral testing to help establish the clinical picture and determine the urgency of intervention as acute viral respiratory infection can increase perioperative risk of laryngospasm, bronchospasm, reintubation. Thus, a positive test may lead to medical management with steroids and close observation whereas a negative test may result in earlier operative intervention. We sought to explore these practices by examining the peri-operative outcomes of patients undergoing DLB with a recent history of viral testing. Interestingly, our study showed no association between respiratory viral positivity and increased complications among children undergoing inpatient DLB. Overall rates of complications were low in spite of nearly 74% of procedures performed on ASA fitness class III/IV patients. Nearly one-half of encounters underwent intervention due to concerns for structural airway abnormality. Anatomic airway abnormalities were more common in RVP negative patients; they were diagnosed on DLB in over one-half of RVP negative encounters and one-third of RVP positive encounters. Despite viral panel result, concurrent endoscopic intervention was common, performed in nearly 30% of patients overall. We identified that while minor complications are common (oxygen desaturation occurred in almost half of all patients), they responded to minimal intervention (oxygen supplementation). The only major complication observed were laryngospasm and the need for reintubation. No other major complications were noted in this study.

Our findings in the context of viral testing results are supported by previous research by Tait and Knight which showed no increase of complications in children with URTIs at the time of surgery (based on symptoms) compared to control patients [8] . A subsequent prospective study showed no differences in perioperative laryngospasm, bronchospasm, or apnea between groups without URTI, with recent URTI, and with active URTI [9] .

In contrast, associations have been found between URTIs and bronchospasm, laryngospasm, and oxygen desaturation in a variety of other studies [1,2,10]. Cohen and Cameron found that patients with URTI were more likely to experience respiratory-related complications [1].

However, timing of infection in relation to surgery was not established and the study relied on symptoms for URTI diagnosis. Further, Tait et al. studied adverse respiratory event incidence and risk factors for patients undergoing elective surgery who were asymptomatic, had active URTI, or had recent (past 4 weeks) URTI [4] . They determined that there was no difference in incidence of laryngospasm and bronchospasm, but active and recent URTI patients had more overall events, as well as more breath-holding spells, oxygen desaturations (SpO2 < 90%), and severe coughing events compared to children without URTI. Still another study found that patients with a history of URTI in the previous two weeks had a 3.5-fold increase in prevalence of respiratory complications [8].

The heterogeneity in findings within the literature may be attributable to different methods used to establish URTI diagnosis. The diagnosis is often defined by the presence of symptoms reported by the parent/guardian of the patients or within the patient's medical record [11] .

Studies have found an increased risk of complications by using symptom history 30 days prior to surgery and also by evaluating symptoms at 2 weeks prior to surgery [12] . This study, with data on both symptoms and objective RVP assessments, as well as an analysis of the time interval between viral infection and bronchoscopy was designed to address these limitations. We found that symptom-based URTI criteria were met in 20.5% of encounters compared to a URTI diagnosis rate of 45.5% when RVP was used. Interestingly, 25.0% of RVP positive encounters were deemed URTIs based on symptoms alone and 16.7% of RVP negative encounters met symptom criteria for URTI. As a result, symptom-based URTI definitions do not appear to be a reliable measure for estimating RVP findings. The relatively low rate of symptom-based diagnosis compared to RVP-based diagnosis could be due to the RVP's ability to identify the DNA of a viral pathogen that is present but not causing clinically concerning symptoms. The low correlation between the two tests might be a result of the symptoms being caused by a disease process other than upper respiratory tract infection in the hospitalized patients. Furthermore, the symptom-based diagnosis results could be confounded by comorbid conditions and are limited by what was documented in the electronic medical record. In another study, Parnis et al. found that just 4.8% of patients that reported symptoms had a virus isolated on an immunofluorescence assay. Neither the patients who had URTI in the preceding 6 weeks nor the patients who tested positive for a viral pathogen had an increased probability of anesthetic complications [6] .

DLBs are commonly performed at our tertiary pediatric hospital, which may have contributed to the low complication rate. Airway instrumentation such as foreign body removal induces mucosal trauma, which may lead to postoperative complications. Two-thirds of patients did not require airway implementation beyond DLB, which may have contributed to overall low major complication rate. The treatment planning required for those patients who were found to have structural airway anomalies may have contributed to the 11-day median length of stay seen in this cohort. This study has several limitations. First, the retrospective nature of this study limits the characterization of perioperative outcomes to what is available in the medical record. In this study, patients were excluded if they did not have an RVP recorded within 6 weeks of DLB, were readmitted close to birth, required a tracheostomy, or had multiple surgical interventions beyond the airway. This was to create a sample that better represented those undifferentiated patients who present to the hospital with respiratory distress and do not have extremely complex healthcare needs that could contribute to adverse surgical outcomes. In doing so, our limited sample size may not have sufficient power to show any associations between RVP positivity and surgical complications should they exist. The outcomes of this study were not intended to apply to medically complex children or patients with known airway abnormalities. However, DLBs were performed in select patients for whom RVP was positive when medically indicated, specifically for those patients whose overall status warranted a surgical procedure despite a known URTI. Surgeons often elect to proceed to the operating room in order to visualize the patient's airway and determine the etiology of obstruction. In this way, this study population does not represent patients presenting for elective surgery for whom surgery is delayed due to suspected URTI. Additionally, only patients who had an RVP taken were compared. The decision to order RVP testing is typically made by emergency department personnel or primary treatment team. These patients received this test because there was a concern for infection causing acute respiratory distress, although RVP is not typically ordered for straightforward URTI. RVP is deferred in patients with high suspicion for structural abnormalities or known airway pathology and low concern for viral illness. Patients with positive RVPs are spared of inappropriate antibiotics and receive proper transmission-based precautions to prevent spread of infections [13, 14] . If the RVP is negative, the provider must consider alternative etiologies leading to respiratory distress. It is possible that patients in both groups had a bacterial or viral pathogen not tested for on the RVP. It is also expected that there were patients who received DLB but were not able to be included because the RVP test was not administered.

We demonstrate that major perioperative complications are infrequent following inpatient airway 

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