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Cuffed endotracheal tubes in neonates and infants undergoing cardiac surgery are not associated with airway complications
Journal of Clinical Anesthesia (2016) 33, 422–427
Original Contribution
Cuffed endotracheal tubes in neonates and infants undergoing cardiac surgery are not associated with airway complications☆ Jennifer C. DeMichele MD a,⁎, Nikhil Vajaria MD b , Hongyue Wang PhD c , Dawn M. Sweeney MD (Associate Professor)d , Karen S. Powers MD (Professor)a , Jill M. Cholette MD (Assistant Professor of Pediatrics)a a
Departments of Pediatrics, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642, USA Department of Anesthesiology, Rush-Copley Medical Center, 2000 Ogden Ave, Aurora, IL, USA c Department of Statistics, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642, USA d Department of Anesthesiology, University of Rochester, 601 Elmwood Ave, Rochester, NY, 14642, USA b
Received 6 December 2015; revised 11 March 2016; accepted 23 April 2016
Keywords: Postextubation stridor; Congenital heart disease; Endotracheal intubation; Pediatric anesthesia
Abstract Study Objective: To determine the incidence of postoperative airway complications in infants b 5 kg in weight undergoing cardiac surgery intubated with Microcuff (Kimberley-Clark, Roswell, GA) endotracheal tubes (ETTs). Design: Retrospective review of infants weighing b 5.0 kg with congenital heart disease (CHD) presenting for cardiac surgery. Setting: Single-center, tertiary pediatric cardiac critical care unit at a university hospital. Patients: A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD from 2008 to 2013. Intervention: Intubation with Microcuff (Kimberley-Clark) ETTs. Study Design: Retrospective review of infants weighing b 5.0 kg with CHD presenting for cardiac surgery to a single-center tertiary care university hospital. Measurements: Perioperative data were collected. Primary outcome was development of tracheal stenosis and/or reintubation for stridor. Stridor was defined as mild (≤2 doses of racemic epinephrine), moderate (N 2 doses of racemic epinephrine), or severe (requiring reintubation). Secondary outcomes were variables possibly contributing to postextubation stridor. Infants with a tracheostomy, airway anomalies, and death prior to initial extubation were excluded. Logistic regression analysis was performed to evaluate the association between clinical risk factors and the incidence of postextubation stridor. Results: A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD from 2008 to 2013; 12 subjects were excluded for death prior to initial extubation. No infant developed tracheal stenosis. The incidence of any stridor was 20.9% (95% confidence interval, 15.8%-27.1%) with severe stridor in 2 cases (1%). Age at surgery, weight, duration of intubation, dexamethasone use, and ETT size were not significantly associated with postextubation stridor. Presence of a comorbidity was significantly associated with stridor (P = .01).
☆
The authors have no potential conflicts of interests or sources of financial assistance for this study. ⁎ Corresponding author at: University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA. Tel.: +1 585 276 3244. E-mail addresses: [email protected] (J.C. DeMichele;), [email protected] (N. Vajaria), [email protected] (H. Wang), [email protected] (D.M. Sweeney), [email protected] (K.S. Powers), [email protected] (J.M. Cholette). http://dx.doi.org/10.1016/j.jclinane.2016.04.038 0952-8180/© 2016 Elsevier Inc. All rights reserved.
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Conclusions: Microcuff ETTs in infants b 5.0 kg in weight undergoing cardiac surgery are associated with a low incidence of severe postextubation stridor. Because cuffed ETTs allow for improved control of ventilation/oxygenation and decreased risk of aspiration, they should be considered for use in this high-risk population. Larger studies are needed to confirm these results. © 2016 Elsevier Inc. All rights reserved.
1. Introduction Traditionally, cuffed endotracheal tubes (ETTs) are avoided in neonates and small infants for concern of development of airway complications including postextubation stridor, laryngeal edema, and/or subglottic tracheal stenosis/ injury [1–5]. Historically, cuffed ETT tubes have been reserved for children older than 8 years, when the laryngeal structure changes from cone to cylindrical shape, better accommodating the bulk of an ETT cuff [6]. Uncuffed ETTs have been deemed safer because lack of a cuff enables a larger internal diameter tube size, allowing for lower airway resistance and more efficient suctioning of tracheobronchial secretions [3,7]. In addition, it has been theorized that uncuffed ETTs exert less pressure on subglottic tracheal mucosa which decreases risk of airway swelling and postextubation stridor [5,7]. Accordingly, the risk for airway mucosal injury, glottic injury, and chance of bronchial intubation/injury often deters clinicians from using cuffed ETTs, particularly in neonates and small infants [1–3,5–8]. However, cuffed ETTs have multiple benefits including (1) more accurate capnographic tracing and spirometric tidal volume measurement, (2) improved control of ventilation and maintenance of airway pressures improving oxygenation, (3) fewer airway manipulations to upsize the ETT tube, and (4) reduced microaspiration [9–12]. Furthermore, airway injury/complications are often unrelated to the presence of a cuffed ETT and are secondary to other factors including multiple intubation attempts, prolonged duration of intubation, concurrent upper respiratory infection, reflux/aspiration, and improper ETT size [4,13]. MicroCuff (Kimberley-Clark, Roswell, GA) ETTs and other high-compliance, low-pressure cuffed ETTs are made of a polyurethane material that provides an effective seal at lower pressures, resulting in decreased compression and ischemia to the tracheal mucosa with reduced likelihood of airway swelling [3,10,11]. Recently, a small case series strongly advised against the use of Microcuff ETTs in infants b 6 months of age and/or b 3 kg in weight due to the development of postextubation stridor. [4]. We present our experience with the use of Microcuff ETT in neonates and infants b 5 kg in weight with congenital heart disease (CHD) undergoing cardiac surgical palliations or reparative procedures. Few data exist describing the airway complication rate of Microcuff ETT in this high-risk patient population. We hypothesize that cuffed ETTs allow for consistent positive airway pressure during postoperative mechanical
ventilation, improving control of oxygenation and ventilation in infants undergoing cardiac surgery, without inciting airway complications.
2. Methods We performed a retrospective chart review of sequential infants weighing b 5 kg with CHD presenting to the University of Rochester Medical Center (URMC) in Rochester, NY, for surgical repair or palliation from January 1, 2008, to June 30, 2013. Infants with a preexisting tracheostomy or known airway anomalies, and/or who died prior to initial extubation were excluded. Data collected included weight, length, gestational age at time of birth, days old on day of surgery, gender, cardiac diagnosis, and type of cardiac procedure performed. The presence of a “significant” comorbidity, defined as (1) a documented chromosomal or suspected genetic abnormality due to significant dysmorphic features on examination (ie, DiGeorge and velocardiofacial syndrome), (2) extracardiac abnormality/ malformation (ie, trachea-esophageal fistula), or (3) previously diagnosed significant medical comorbidity (ie, necrotizing enterocolitis). The Risk Adjustment for Congenital Heart Surgery Score and Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score were compiled for each procedure. The number of lifetime intubations, ETT manipulations (at initial, intraoperative, and postoperative periods), which included ETT exchanges for uncuffed to cuffed, plugged ETT tubes, and/or size changes, multiple ETT attempts, and duration of intubation were also recorded. Primary outcome was the incidence of airway complications including tracheal stenosis, reintubation for upper airway edema, and presence of postextubation stridor. Postextubation stridor was defined as follows: mild (requiring ≤ 2 doses of racemic epinephrine), moderate (requiring N 2 doses of racemic epinephrine), or severe (requiring reintubation and/or eventual tracheostomy for upper airway obstruction/abnormality). Administration of dexathamethasone (before and after extubation), ETT size, number of intubation attempts, and cuff pressure (when available) were recorded. ENT consultation and findings on assessment, hospital length of stay, and hospital-acquired infections were recorded. During the study period, 3 attending anesthesiologists performed the pediatric cardiac cases. ETT size was selected by the anesthesiologist on the day of surgery. If an uncuffed ETT was already in place, it was changed to a cuffed tube at
424 the time of surgery. Cuffed ETTs were upsized for the presence of significant air leak also at the time of surgery. Per standard practice at URMC, placement of a 3.5 ETT was attempted for all neonates/infants initially, with placement of a 3.0 ETT at the discretion of the attending anesthesiologist if the airway would not accommodate the larger ETT. Also per local standard of care at URMC, all infants weighing N 3 kg undergo a transesophageal ultrasound in the operating room (OR) as they come off of cardiopulmonary bypass for postoperative surgical assessment. In all cases, infants were transferred directly from the OR to the pediatric cardiac intensive care unit intubated and sedated for postoperative management. Per local standard of care at URMC, respiratory therapists check ETT cuff pressure on ventilated patients once per shift. Current practice is to remove all air from the ETT cuff, then inflate the ETT cuff until a minimal air leak is observed, with a goal cuff pressure of 10 to 12 mm Hg. Following discussion with the intensivist, if it was determined that the infant could be adequately ventilated with the cuff down, the respiratory therapist would then deflate the cuff. Children were weaned from mechanical ventilation as their cardiopulmonary and fluid status allowed. Those at risk for pulmonary hypertensive crisis were managed accordingly with continuous sedation and neuromuscular blockade as deemed appropriate. Preextubation dexamethasone and postextubation racemic epinephrine were given at the discretion of the pediatric intensivist based on the duration of intubation and/or presence of an air leak as demonstrated by audible examination and volume return on the ventilator. Standard dexamethasone dosing was utilized (0.5 mg/kg intravenous), and generally given for 1 to 2 doses prior extubation and postextubation for clinically relevant stridor not responsive to racemic epinephrine. Statistical analyses were performed using version 9.3 of the SAS System for Windows (SAS institute Inc, Cary, NC). Descriptive statistics were used to summarize study variables with mean and standard deviations for continuous variable and frequencies and percentages for categorical variables. Demographic and clinical factors were compared between infants who developed postextubation stridor and those who did not using t tests for continuous variables and χ2/Fisher exact test for categorical variables. Wilcoxon ranked sum test was used for nonnormally distributed data. Multiple logistic regression analysis was performed to evaluate the association between potential risk factors and the development of postextubation stridor. All tests were 2 sided, and a P value b .05 was considered statistically significant.
3. Results A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD; 12 were excluded due to death prior initial extubation so that 196 subjects were studied. No patients were excluded for preexisting tracheostomy or airway anomalies.
J.C. DeMichele et al. Mean weight was 3.6 ± 0.7 kg. The majority of infants were term (73%). Sixty-two percent of subjects had a Risk Adjustment For Congenital Heart Surgery score N 4, and 67% had a Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score N 4. Seventy-one percent had a 3.5 Microcuffed ETT placed for the initial surgery. One-third (33%) of infants had single ventricle physiology, one-third (34%) were b 3 kg in weight, and approximately one-third (28%) of infants had an associated comorbidity (Table 1). Fifty-one (26%) had ETT manipulation in the OR just prior to surgery. Of these, 62% had N 1 intubation attempt, 16% had their preoperative uncuffed ETT exchanged to a cuffed ETT, and 24% had a change in their ETT size at the discretion of the anesthesiologist. Seventy-one percent received dexamethasone prophylactically before extubation trial and 34.5% received it postextubation. No infants developed tracheal stenosis. The incidence of any stridor was 20.5%. Severe stridor occurred in 2 cases (1%). Because of such a low incidence of severe stridor, all infants who developed any postextubation stridor were included in subsequent data analyses (Table 2). Age at the time of surgery, weight, surgical severity score, duration of intubation, ETT manipulation, prophylactic dexamethasone use, ETT size, prematurity, inflated ETT cuff, maximum ETT cuff pressure (n = 27), weight b 3 kg, or cyanosis postoperatively were not significantly associated with postextubation stridor (Table 3). Presence of comorbidity was significantly associated with the development of postextubation stridor (P = .01). However, upon multiple logistic regression analysis, having a comorbidity only trended to confer a higher risk in the development of postextubation stridor (odds ratio, 2.21 [0.994-4.91]; P = .051; Table 4), and OR manipulation of
Table 1
Subject characteristics
Characteristic (n = 196) Age (d) Weight (kg) Male sex Gestational age Term (N 38 wk) Late preterm (35-37 6/7 wk) Preterm (30-34 wk 6/7 wk) Undocumented Comorbidity Chromosomal abnormality Single-ventricle physiology STS-EACTS N 4 RACHS N 4 3.0 ETT size 3.5 ETT size 4.0 ETT size
34 ± 52.6 3.6 ± 0.7 104 (52%) 97 (73%) 25 (19%) 9 (7%) 67 56 (28%) 30 (15%) 59 (33%) 139 (71%) 131 (67%) 51 (26%) 140 (71%) 5 (3%)
STS-EACTS = Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score; RACHS = Risk Adjustment For Congenital Heart Surgery Score; ETT = endotracheal tube.
Cuffed endotracheal tubes in neonates and infants
425
Table 2 Primary outcome: postextubation stridor and/or significant airway complications
Microcuff ETT). After 48 hours of dexamethasone, he was extubated without complication or stridor recurrence.
Population (n = 196) None Mild (≤2 doses of racemic epi) Moderate (N 2 doses of racemic epi) Severe (requiring reintubation or tracheostomy) Total (all postextubation stridor) Tracheal stenosis
155 (79.1%) 37 (18.8%) 2 (1%) 2 (1%) 41 (20.5%) 0
the ETT trended to confer a protective effect (odds ratio, 0.36 [0.128-1.00]). Of the 2 infants who developed severe stridor, 1 received 7 doses of racemic epinephrine and 7 doses of dexamethasone postextubation, but did not require reintubation. This neonate with transposition of the great arteries and intact ventricular septum was status post an arterial switch operation. She was 3.16 kg in weight and 7 days old at the time of surgery, with a significant pectus excavatum. She was intubated with a 3.0 cuffed ETT for 6 days. Postoperative laryngoscopy demonstrated bilaterally vocal cord immobility. Direct laryngeal bronchoscopy showed a normal larynx, subglottis, trachea and bronchi, and evidence of severe aspiration. She recovered fully, and the immobility was attributed to temporary surgical traction injury. The second infant was born at 35 weeks' gestation with a suspected genetic disorder including abdominal situs inversus. He was 3.9 kg in weight undergoing stage II palliation for hypoplastic left heart syndrome, transposed great arteries, and critical pulmonary stenosis at day of life 74. He failed extubation on postoperative day 4 secondary to airway obstruction requiring reintubation with a smaller ETT size (initial 3.5 ETT replaced with a 3.0
Table 3
4. Discussion Our study suggests that Microcuff ETTs can be utilized in infants weighing b 5 kg with CHD undergoing cardiac surgery and prolonged intubation without increased incidence of tracheal stenosis or severe postextubation stridor. The incidence of severe postextubation stridor in our study was 1%. Other studies have shown slightly higher incidence rates for severe postoperative airway complications, but variations in study methodology and definitions of post–airway complications preclude direct comparison. In these studies, incident rates of postextubation airway complications ranged from 1% to 7.4% for uncuffed and cuffed ETTs [1,2,4,6,11,14]. Most included older patients had variable definitions of postextubation complication rates, did not use Microcuff or cuffed ETTs, and did not look specifically at this specific patient population, and majority of patients did not require postoperative or prolonged mechanical ventilation. Kolatat et al [15] focused on neonates managed with mechanical ventilation for N 4 days, intubated with uncuffed ETTs, for any signs of postextubation upper airway obstruction. They found a higher incidence rate (31.1%) of stridor despite the use of uncuffed ETTs. [15] These results suggest that uncuffed ETTs do not reliably protect against postextubation stridor in neonates intubated for more than 4 days. In addition, Mossad and Youssef [14] examined postextubation airway complications (subglottic stenosis) in infants undergoing CHD surgeries. The patient population was more similar to our study that other studies; however, only 2 of the 17 patients who developed subglottic stenosis had cuffed ETTs and only
Clinical factors and postextubation stridor a
Age at surgery (d) , mean ± SD Weight (kg) a, mean ± SD Duration of intubation (d), mean ± SD Number of ETT tape changes, mean ± SD Comorbidities b,d, n (%) Term vs preterm b, n (%) Cuff up vs cuff down b, n (%) Max cuff pressure (mm Hg) a, mean ± SD ≥ 3.5 ETT size c, n (%) ≤3 kg vs N 3 kg b, n (%) Cyanotic vs acyanotic infants b, n (%)
No stridor (n = 155)
Stridor (n = 41)
P
30 ± 46 3.5 ± 0.61 7.5 ± 10 1.5 ± 2.3 37 (25) 127 (82) 107 (82) 14 ± 5 117 (75) 41 (27) 43 (27)
52 ± 71 3.6 ± 0.76 9 ± 17 1.8 ± 2.8 18 (46) 31/(76) 27 (69) 8±5 28 (68) 9 (22) 12 (29)
.070 .472 .609 .412 .010 .320 .095 .239 .351 .543 .847
The only variable that demonstrated significance is in bold font. ETT = endotracheal tube. a t Test. b 2 χ Test. c Fisher exact test. d DiGeorge, Trisomy 21, unknown genetic disorder, necrotizing enterocolitis anatomical abnormality.
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J.C. DeMichele et al.
Table 4 Multiple logistic regression of clinical risk factors and postextubation stridor
Age at surgery (age) Weight (kg) Duration of intubation (d) Comorbidities Operating room manipulation of ETT tube a
OR (95% CI)
P
1.00 (0.998-1.01) 0.813 (0.309-2.14) 0.997 (0.961-1.04) 2.072 (0.916-4.69) 0.358 (0.128-1.004)
.197 .578 .296 .051 .051
OR = odds ratio; CI = confidence interval; ETT = endotracheal tube. a ETT exchange for change in ETT size, ETT exchange of uncuffed to cuffed, ETT exchange for a plugged ETT, and multiple intubation attempts.
188 were b 1 month of age. They found an incidence of significant airway complications of 2.1% compared with our 1%, implying a possible protective effect of cuffed ETTs compared with uncuffed. However, further studies would have to determine whether cuffed ETTs actually confer a benefit against significant airway complications in this patient population. Newth et al [11] performed a prospective single-center study documenting their experience using high-compliance, low-pressure cuffed ETTs vs uncuffed ETTs in critically ill children admitted to the intensive care unit requiring mechanical ventilation during a 1-year period. They found no significant difference in the use of racemic epinephrine for postextubation subglottic edema between cuffed vs uncuffed groups, or differences in successful extubation rates or need for tracheostomy. Four hundred seventy six patients were younger than 2 years, of whom 269 were postcardiac surgery. Of these, the minority had cuffed ETT (n = 54), with 215 having uncuffed ETTs. The postextubation stridor rate was similar for infants b 24 months of age (16.9% uncuffed vs 17% cuffed). No specific data collection or subgroup analyses were conducted for those infants intubated for cardiac surgery. The greatest concern regarding use of a cuffed ETT remains the potential for damage to the tracheal mucosa from excessive inflation of the cuff [8]. Neonates and infants with singleventricle physiology and intracardiac mixing lesions causing systemic desaturation and labile balance between systemic to pulmonary blood flow are at increased risk for developing tracheal mucosa injury from decreased tissue oxygenation and perfusion. Fluctuations in cardiac output occurring during cardiopulmonary bypass and in the immediate postoperative period may cause inadequate tissue blood flow and oxygenation, further increasing tissue mucosal injury. Our study demonstrates that infants less than 3 kg in weight and cyanotic infants (ie, infants undergoing surgical palliations with intracardiac mixing that leaves them cyanotic post-operatively) conferred no higher risk of postextubation stridor or airway complications despite more complex intra and postoperative courses. Other factors such as multiple ETT exchanges for inappropriate size, multiple ETT intubation attempts and intubations,
preexisting comorbidities, and/or severe reflux likely contribute to the development of postextubation stridor in infants requiring prolonged ventilation. The possible association of comorbidities with the development of postextubation stridor found in this study needs to be examined further in a larger more detailed analysis. In addition, our study demonstrated that OR ETT manipulation trended to confer a decrease risk in postextubation stridor. Whether this protective effect was possibly due to the exchange from an uncuffed to a cuffed ETT, or possibly due to the correct size ETT being chosen, needs to also be examined in a larger more detailed analysis. Limitations of this study include all of the well-known limitations of retrospectively designed studies. A prospective study would allow for more objective determination of postextubation airway complications and their association with patient variables as well as possibly compare the complication rates between cuffed and uncuffed ETTs in this high-risk population. Our findings in this study provide evidence against the historically held belief that cuffed ETTs should be contraindicated in children younger than 8 years. This study demonstrates that the incidence of severe postextubation stridor is low in small infants with CHD undergoing cardiac surgery. Because cuffed ETTs allow for improved control of ventilation and oxygenation, decreased risk of aspiration, and improved pulmonary toilet, and do not appear to significantly increase airway complications, they should be used for neonates and infants who will require prolonged postoperative mechanical ventilation. Larger prospective studies in pediatric cardiac surgical patients are needed to confirm these results.
References [1] Weiss M, Dullenkopf A, Fisher JE, Keller C, Gerber AC. Prospective randomized controlled multi-centre trial of cuffed or uncuffed endotracheal tubes in small children. Br J Anaesth 2009;102: 867-73. [2] Weiss M, Dullenkopf A. Cuffed tracheal tubes in children: past, present, future. Expert Rev Med Devices 2007;4:73-82. [3] Sathyamoorthy M, Lerman J, Lakshminrusimha S, Feldman D. Inspiratory stridor after tracheal intubation with a MicroCuff tracheal tube in three young infants. Anesth 2013;118:748-50. [4] Litman RSDO, Maxwell LGMD. FAAP: cuffed vs uncuffed endotracheal tubes in pediatric anesthesia: the debated should finally end. Editorial. Anesthesiology 2013;118:500-1. [5] Azarfarn R, Seyedhejazi M, Golzari SEJ, Bilehjani E, Ghabili K, Alizadehas A. Do pediatric patients undergoing cardiac surgeries require larger-sise cuffed endotracheal tubes? A prospective study. Pediatr Anesth 2012;23:228-32. [6] Khine H, Corldry D, Kettrick R. Comparison of cuffed and uncuffed endotracheal tubes in young children during general anesthesia. Anesthesiology 1997;86:627-31. [7] Bhardwaj N. Pediatric cuffed endotracheal tubes. J Anesthesiol Clin Pharm 2013;29:13-6.
Cuffed endotracheal tubes in neonates and infants [8] Wei JL, Bond J. Management and prevention of endotracheal intubation injury in neonates. Curr Opin Otolaryngol Head Neck Surg 2011;19: 474-7. [9] Tobias JD. Pediatric anesthesia: “pediatric airway anatomy may not be what we thought: implications for clinical practice and the use of cuffed endotracheal tubes.”. John Wiley & Sons Ltd; 2014 1-11. [10] Taylor C, Subaiya L, Corsino D. Pediatric cuffed endotracheal tubes: an evolution of care. Oschner J 2011;11:52-6. [11] Newth CJ, Rachman B, Patel N, Hammer J. The use of cuffed versus uncuffed endotracheal tubes in pediatric intensive care. J Pediatr 2004; 144:333-7.
427 [12] Dorsey D, Bowman S, Klein M, Archer D. Perioperative use of cuffed endotracheal tubes is advantageous in young pediatric burn patients. Burns 2010;36:856-60. [13] Salgo B, Schmitz G, Henze K. Evaluation of a new recommendation for improved cuffed tracheal tube size selection in infants and small children. Acta Anaesthesiol Scand 2006;50:557-61. [14] Mossad E, Youssef G. Subglottic stenosis in children undergoing repair of congenital heart defects. J Cardiothorac Vasc Anesth 2009;23:658-62. [15] Kolatat T, Aunganon K, Yosthiem P. Airway complications in neonates who received mechanical ventilation. J Med Assoc Thai 2002;85(Suppl. 2):S455-62.
Original Contribution
Cuffed endotracheal tubes in neonates and infants undergoing cardiac surgery are not associated with airway complications☆ Jennifer C. DeMichele MD a,⁎, Nikhil Vajaria MD b , Hongyue Wang PhD c , Dawn M. Sweeney MD (Associate Professor)d , Karen S. Powers MD (Professor)a , Jill M. Cholette MD (Assistant Professor of Pediatrics)a a
Departments of Pediatrics, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642, USA Department of Anesthesiology, Rush-Copley Medical Center, 2000 Ogden Ave, Aurora, IL, USA c Department of Statistics, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642, USA d Department of Anesthesiology, University of Rochester, 601 Elmwood Ave, Rochester, NY, 14642, USA b
Received 6 December 2015; revised 11 March 2016; accepted 23 April 2016
Keywords: Postextubation stridor; Congenital heart disease; Endotracheal intubation; Pediatric anesthesia
Abstract Study Objective: To determine the incidence of postoperative airway complications in infants b 5 kg in weight undergoing cardiac surgery intubated with Microcuff (Kimberley-Clark, Roswell, GA) endotracheal tubes (ETTs). Design: Retrospective review of infants weighing b 5.0 kg with congenital heart disease (CHD) presenting for cardiac surgery. Setting: Single-center, tertiary pediatric cardiac critical care unit at a university hospital. Patients: A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD from 2008 to 2013. Intervention: Intubation with Microcuff (Kimberley-Clark) ETTs. Study Design: Retrospective review of infants weighing b 5.0 kg with CHD presenting for cardiac surgery to a single-center tertiary care university hospital. Measurements: Perioperative data were collected. Primary outcome was development of tracheal stenosis and/or reintubation for stridor. Stridor was defined as mild (≤2 doses of racemic epinephrine), moderate (N 2 doses of racemic epinephrine), or severe (requiring reintubation). Secondary outcomes were variables possibly contributing to postextubation stridor. Infants with a tracheostomy, airway anomalies, and death prior to initial extubation were excluded. Logistic regression analysis was performed to evaluate the association between clinical risk factors and the incidence of postextubation stridor. Results: A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD from 2008 to 2013; 12 subjects were excluded for death prior to initial extubation. No infant developed tracheal stenosis. The incidence of any stridor was 20.9% (95% confidence interval, 15.8%-27.1%) with severe stridor in 2 cases (1%). Age at surgery, weight, duration of intubation, dexamethasone use, and ETT size were not significantly associated with postextubation stridor. Presence of a comorbidity was significantly associated with stridor (P = .01).
☆
The authors have no potential conflicts of interests or sources of financial assistance for this study. ⁎ Corresponding author at: University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA. Tel.: +1 585 276 3244. E-mail addresses: [email protected] (J.C. DeMichele;), [email protected] (N. Vajaria), [email protected] (H. Wang), [email protected] (D.M. Sweeney), [email protected] (K.S. Powers), [email protected] (J.M. Cholette). http://dx.doi.org/10.1016/j.jclinane.2016.04.038 0952-8180/© 2016 Elsevier Inc. All rights reserved.
Cuffed endotracheal tubes in neonates and infants
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Conclusions: Microcuff ETTs in infants b 5.0 kg in weight undergoing cardiac surgery are associated with a low incidence of severe postextubation stridor. Because cuffed ETTs allow for improved control of ventilation/oxygenation and decreased risk of aspiration, they should be considered for use in this high-risk population. Larger studies are needed to confirm these results. © 2016 Elsevier Inc. All rights reserved.
1. Introduction Traditionally, cuffed endotracheal tubes (ETTs) are avoided in neonates and small infants for concern of development of airway complications including postextubation stridor, laryngeal edema, and/or subglottic tracheal stenosis/ injury [1–5]. Historically, cuffed ETT tubes have been reserved for children older than 8 years, when the laryngeal structure changes from cone to cylindrical shape, better accommodating the bulk of an ETT cuff [6]. Uncuffed ETTs have been deemed safer because lack of a cuff enables a larger internal diameter tube size, allowing for lower airway resistance and more efficient suctioning of tracheobronchial secretions [3,7]. In addition, it has been theorized that uncuffed ETTs exert less pressure on subglottic tracheal mucosa which decreases risk of airway swelling and postextubation stridor [5,7]. Accordingly, the risk for airway mucosal injury, glottic injury, and chance of bronchial intubation/injury often deters clinicians from using cuffed ETTs, particularly in neonates and small infants [1–3,5–8]. However, cuffed ETTs have multiple benefits including (1) more accurate capnographic tracing and spirometric tidal volume measurement, (2) improved control of ventilation and maintenance of airway pressures improving oxygenation, (3) fewer airway manipulations to upsize the ETT tube, and (4) reduced microaspiration [9–12]. Furthermore, airway injury/complications are often unrelated to the presence of a cuffed ETT and are secondary to other factors including multiple intubation attempts, prolonged duration of intubation, concurrent upper respiratory infection, reflux/aspiration, and improper ETT size [4,13]. MicroCuff (Kimberley-Clark, Roswell, GA) ETTs and other high-compliance, low-pressure cuffed ETTs are made of a polyurethane material that provides an effective seal at lower pressures, resulting in decreased compression and ischemia to the tracheal mucosa with reduced likelihood of airway swelling [3,10,11]. Recently, a small case series strongly advised against the use of Microcuff ETTs in infants b 6 months of age and/or b 3 kg in weight due to the development of postextubation stridor. [4]. We present our experience with the use of Microcuff ETT in neonates and infants b 5 kg in weight with congenital heart disease (CHD) undergoing cardiac surgical palliations or reparative procedures. Few data exist describing the airway complication rate of Microcuff ETT in this high-risk patient population. We hypothesize that cuffed ETTs allow for consistent positive airway pressure during postoperative mechanical
ventilation, improving control of oxygenation and ventilation in infants undergoing cardiac surgery, without inciting airway complications.
2. Methods We performed a retrospective chart review of sequential infants weighing b 5 kg with CHD presenting to the University of Rochester Medical Center (URMC) in Rochester, NY, for surgical repair or palliation from January 1, 2008, to June 30, 2013. Infants with a preexisting tracheostomy or known airway anomalies, and/or who died prior to initial extubation were excluded. Data collected included weight, length, gestational age at time of birth, days old on day of surgery, gender, cardiac diagnosis, and type of cardiac procedure performed. The presence of a “significant” comorbidity, defined as (1) a documented chromosomal or suspected genetic abnormality due to significant dysmorphic features on examination (ie, DiGeorge and velocardiofacial syndrome), (2) extracardiac abnormality/ malformation (ie, trachea-esophageal fistula), or (3) previously diagnosed significant medical comorbidity (ie, necrotizing enterocolitis). The Risk Adjustment for Congenital Heart Surgery Score and Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score were compiled for each procedure. The number of lifetime intubations, ETT manipulations (at initial, intraoperative, and postoperative periods), which included ETT exchanges for uncuffed to cuffed, plugged ETT tubes, and/or size changes, multiple ETT attempts, and duration of intubation were also recorded. Primary outcome was the incidence of airway complications including tracheal stenosis, reintubation for upper airway edema, and presence of postextubation stridor. Postextubation stridor was defined as follows: mild (requiring ≤ 2 doses of racemic epinephrine), moderate (requiring N 2 doses of racemic epinephrine), or severe (requiring reintubation and/or eventual tracheostomy for upper airway obstruction/abnormality). Administration of dexathamethasone (before and after extubation), ETT size, number of intubation attempts, and cuff pressure (when available) were recorded. ENT consultation and findings on assessment, hospital length of stay, and hospital-acquired infections were recorded. During the study period, 3 attending anesthesiologists performed the pediatric cardiac cases. ETT size was selected by the anesthesiologist on the day of surgery. If an uncuffed ETT was already in place, it was changed to a cuffed tube at
424 the time of surgery. Cuffed ETTs were upsized for the presence of significant air leak also at the time of surgery. Per standard practice at URMC, placement of a 3.5 ETT was attempted for all neonates/infants initially, with placement of a 3.0 ETT at the discretion of the attending anesthesiologist if the airway would not accommodate the larger ETT. Also per local standard of care at URMC, all infants weighing N 3 kg undergo a transesophageal ultrasound in the operating room (OR) as they come off of cardiopulmonary bypass for postoperative surgical assessment. In all cases, infants were transferred directly from the OR to the pediatric cardiac intensive care unit intubated and sedated for postoperative management. Per local standard of care at URMC, respiratory therapists check ETT cuff pressure on ventilated patients once per shift. Current practice is to remove all air from the ETT cuff, then inflate the ETT cuff until a minimal air leak is observed, with a goal cuff pressure of 10 to 12 mm Hg. Following discussion with the intensivist, if it was determined that the infant could be adequately ventilated with the cuff down, the respiratory therapist would then deflate the cuff. Children were weaned from mechanical ventilation as their cardiopulmonary and fluid status allowed. Those at risk for pulmonary hypertensive crisis were managed accordingly with continuous sedation and neuromuscular blockade as deemed appropriate. Preextubation dexamethasone and postextubation racemic epinephrine were given at the discretion of the pediatric intensivist based on the duration of intubation and/or presence of an air leak as demonstrated by audible examination and volume return on the ventilator. Standard dexamethasone dosing was utilized (0.5 mg/kg intravenous), and generally given for 1 to 2 doses prior extubation and postextubation for clinically relevant stridor not responsive to racemic epinephrine. Statistical analyses were performed using version 9.3 of the SAS System for Windows (SAS institute Inc, Cary, NC). Descriptive statistics were used to summarize study variables with mean and standard deviations for continuous variable and frequencies and percentages for categorical variables. Demographic and clinical factors were compared between infants who developed postextubation stridor and those who did not using t tests for continuous variables and χ2/Fisher exact test for categorical variables. Wilcoxon ranked sum test was used for nonnormally distributed data. Multiple logistic regression analysis was performed to evaluate the association between potential risk factors and the development of postextubation stridor. All tests were 2 sided, and a P value b .05 was considered statistically significant.
3. Results A total of 208 infants weighing b 5 kg underwent cardiac surgery for CHD; 12 were excluded due to death prior initial extubation so that 196 subjects were studied. No patients were excluded for preexisting tracheostomy or airway anomalies.
J.C. DeMichele et al. Mean weight was 3.6 ± 0.7 kg. The majority of infants were term (73%). Sixty-two percent of subjects had a Risk Adjustment For Congenital Heart Surgery score N 4, and 67% had a Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score N 4. Seventy-one percent had a 3.5 Microcuffed ETT placed for the initial surgery. One-third (33%) of infants had single ventricle physiology, one-third (34%) were b 3 kg in weight, and approximately one-third (28%) of infants had an associated comorbidity (Table 1). Fifty-one (26%) had ETT manipulation in the OR just prior to surgery. Of these, 62% had N 1 intubation attempt, 16% had their preoperative uncuffed ETT exchanged to a cuffed ETT, and 24% had a change in their ETT size at the discretion of the anesthesiologist. Seventy-one percent received dexamethasone prophylactically before extubation trial and 34.5% received it postextubation. No infants developed tracheal stenosis. The incidence of any stridor was 20.5%. Severe stridor occurred in 2 cases (1%). Because of such a low incidence of severe stridor, all infants who developed any postextubation stridor were included in subsequent data analyses (Table 2). Age at the time of surgery, weight, surgical severity score, duration of intubation, ETT manipulation, prophylactic dexamethasone use, ETT size, prematurity, inflated ETT cuff, maximum ETT cuff pressure (n = 27), weight b 3 kg, or cyanosis postoperatively were not significantly associated with postextubation stridor (Table 3). Presence of comorbidity was significantly associated with the development of postextubation stridor (P = .01). However, upon multiple logistic regression analysis, having a comorbidity only trended to confer a higher risk in the development of postextubation stridor (odds ratio, 2.21 [0.994-4.91]; P = .051; Table 4), and OR manipulation of
Table 1
Subject characteristics
Characteristic (n = 196) Age (d) Weight (kg) Male sex Gestational age Term (N 38 wk) Late preterm (35-37 6/7 wk) Preterm (30-34 wk 6/7 wk) Undocumented Comorbidity Chromosomal abnormality Single-ventricle physiology STS-EACTS N 4 RACHS N 4 3.0 ETT size 3.5 ETT size 4.0 ETT size
34 ± 52.6 3.6 ± 0.7 104 (52%) 97 (73%) 25 (19%) 9 (7%) 67 56 (28%) 30 (15%) 59 (33%) 139 (71%) 131 (67%) 51 (26%) 140 (71%) 5 (3%)
STS-EACTS = Society of Thoracic Surgeons and European Association for Cardio-thoracic Surgery score; RACHS = Risk Adjustment For Congenital Heart Surgery Score; ETT = endotracheal tube.
Cuffed endotracheal tubes in neonates and infants
425
Table 2 Primary outcome: postextubation stridor and/or significant airway complications
Microcuff ETT). After 48 hours of dexamethasone, he was extubated without complication or stridor recurrence.
Population (n = 196) None Mild (≤2 doses of racemic epi) Moderate (N 2 doses of racemic epi) Severe (requiring reintubation or tracheostomy) Total (all postextubation stridor) Tracheal stenosis
155 (79.1%) 37 (18.8%) 2 (1%) 2 (1%) 41 (20.5%) 0
the ETT trended to confer a protective effect (odds ratio, 0.36 [0.128-1.00]). Of the 2 infants who developed severe stridor, 1 received 7 doses of racemic epinephrine and 7 doses of dexamethasone postextubation, but did not require reintubation. This neonate with transposition of the great arteries and intact ventricular septum was status post an arterial switch operation. She was 3.16 kg in weight and 7 days old at the time of surgery, with a significant pectus excavatum. She was intubated with a 3.0 cuffed ETT for 6 days. Postoperative laryngoscopy demonstrated bilaterally vocal cord immobility. Direct laryngeal bronchoscopy showed a normal larynx, subglottis, trachea and bronchi, and evidence of severe aspiration. She recovered fully, and the immobility was attributed to temporary surgical traction injury. The second infant was born at 35 weeks' gestation with a suspected genetic disorder including abdominal situs inversus. He was 3.9 kg in weight undergoing stage II palliation for hypoplastic left heart syndrome, transposed great arteries, and critical pulmonary stenosis at day of life 74. He failed extubation on postoperative day 4 secondary to airway obstruction requiring reintubation with a smaller ETT size (initial 3.5 ETT replaced with a 3.0
Table 3
4. Discussion Our study suggests that Microcuff ETTs can be utilized in infants weighing b 5 kg with CHD undergoing cardiac surgery and prolonged intubation without increased incidence of tracheal stenosis or severe postextubation stridor. The incidence of severe postextubation stridor in our study was 1%. Other studies have shown slightly higher incidence rates for severe postoperative airway complications, but variations in study methodology and definitions of post–airway complications preclude direct comparison. In these studies, incident rates of postextubation airway complications ranged from 1% to 7.4% for uncuffed and cuffed ETTs [1,2,4,6,11,14]. Most included older patients had variable definitions of postextubation complication rates, did not use Microcuff or cuffed ETTs, and did not look specifically at this specific patient population, and majority of patients did not require postoperative or prolonged mechanical ventilation. Kolatat et al [15] focused on neonates managed with mechanical ventilation for N 4 days, intubated with uncuffed ETTs, for any signs of postextubation upper airway obstruction. They found a higher incidence rate (31.1%) of stridor despite the use of uncuffed ETTs. [15] These results suggest that uncuffed ETTs do not reliably protect against postextubation stridor in neonates intubated for more than 4 days. In addition, Mossad and Youssef [14] examined postextubation airway complications (subglottic stenosis) in infants undergoing CHD surgeries. The patient population was more similar to our study that other studies; however, only 2 of the 17 patients who developed subglottic stenosis had cuffed ETTs and only
Clinical factors and postextubation stridor a
Age at surgery (d) , mean ± SD Weight (kg) a, mean ± SD Duration of intubation (d), mean ± SD Number of ETT tape changes, mean ± SD Comorbidities b,d, n (%) Term vs preterm b, n (%) Cuff up vs cuff down b, n (%) Max cuff pressure (mm Hg) a, mean ± SD ≥ 3.5 ETT size c, n (%) ≤3 kg vs N 3 kg b, n (%) Cyanotic vs acyanotic infants b, n (%)
No stridor (n = 155)
Stridor (n = 41)
P
30 ± 46 3.5 ± 0.61 7.5 ± 10 1.5 ± 2.3 37 (25) 127 (82) 107 (82) 14 ± 5 117 (75) 41 (27) 43 (27)
52 ± 71 3.6 ± 0.76 9 ± 17 1.8 ± 2.8 18 (46) 31/(76) 27 (69) 8±5 28 (68) 9 (22) 12 (29)
.070 .472 .609 .412 .010 .320 .095 .239 .351 .543 .847
The only variable that demonstrated significance is in bold font. ETT = endotracheal tube. a t Test. b 2 χ Test. c Fisher exact test. d DiGeorge, Trisomy 21, unknown genetic disorder, necrotizing enterocolitis anatomical abnormality.
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J.C. DeMichele et al.
Table 4 Multiple logistic regression of clinical risk factors and postextubation stridor
Age at surgery (age) Weight (kg) Duration of intubation (d) Comorbidities Operating room manipulation of ETT tube a
OR (95% CI)
P
1.00 (0.998-1.01) 0.813 (0.309-2.14) 0.997 (0.961-1.04) 2.072 (0.916-4.69) 0.358 (0.128-1.004)
.197 .578 .296 .051 .051
OR = odds ratio; CI = confidence interval; ETT = endotracheal tube. a ETT exchange for change in ETT size, ETT exchange of uncuffed to cuffed, ETT exchange for a plugged ETT, and multiple intubation attempts.
188 were b 1 month of age. They found an incidence of significant airway complications of 2.1% compared with our 1%, implying a possible protective effect of cuffed ETTs compared with uncuffed. However, further studies would have to determine whether cuffed ETTs actually confer a benefit against significant airway complications in this patient population. Newth et al [11] performed a prospective single-center study documenting their experience using high-compliance, low-pressure cuffed ETTs vs uncuffed ETTs in critically ill children admitted to the intensive care unit requiring mechanical ventilation during a 1-year period. They found no significant difference in the use of racemic epinephrine for postextubation subglottic edema between cuffed vs uncuffed groups, or differences in successful extubation rates or need for tracheostomy. Four hundred seventy six patients were younger than 2 years, of whom 269 were postcardiac surgery. Of these, the minority had cuffed ETT (n = 54), with 215 having uncuffed ETTs. The postextubation stridor rate was similar for infants b 24 months of age (16.9% uncuffed vs 17% cuffed). No specific data collection or subgroup analyses were conducted for those infants intubated for cardiac surgery. The greatest concern regarding use of a cuffed ETT remains the potential for damage to the tracheal mucosa from excessive inflation of the cuff [8]. Neonates and infants with singleventricle physiology and intracardiac mixing lesions causing systemic desaturation and labile balance between systemic to pulmonary blood flow are at increased risk for developing tracheal mucosa injury from decreased tissue oxygenation and perfusion. Fluctuations in cardiac output occurring during cardiopulmonary bypass and in the immediate postoperative period may cause inadequate tissue blood flow and oxygenation, further increasing tissue mucosal injury. Our study demonstrates that infants less than 3 kg in weight and cyanotic infants (ie, infants undergoing surgical palliations with intracardiac mixing that leaves them cyanotic post-operatively) conferred no higher risk of postextubation stridor or airway complications despite more complex intra and postoperative courses. Other factors such as multiple ETT exchanges for inappropriate size, multiple ETT intubation attempts and intubations,
preexisting comorbidities, and/or severe reflux likely contribute to the development of postextubation stridor in infants requiring prolonged ventilation. The possible association of comorbidities with the development of postextubation stridor found in this study needs to be examined further in a larger more detailed analysis. In addition, our study demonstrated that OR ETT manipulation trended to confer a decrease risk in postextubation stridor. Whether this protective effect was possibly due to the exchange from an uncuffed to a cuffed ETT, or possibly due to the correct size ETT being chosen, needs to also be examined in a larger more detailed analysis. Limitations of this study include all of the well-known limitations of retrospectively designed studies. A prospective study would allow for more objective determination of postextubation airway complications and their association with patient variables as well as possibly compare the complication rates between cuffed and uncuffed ETTs in this high-risk population. Our findings in this study provide evidence against the historically held belief that cuffed ETTs should be contraindicated in children younger than 8 years. This study demonstrates that the incidence of severe postextubation stridor is low in small infants with CHD undergoing cardiac surgery. Because cuffed ETTs allow for improved control of ventilation and oxygenation, decreased risk of aspiration, and improved pulmonary toilet, and do not appear to significantly increase airway complications, they should be used for neonates and infants who will require prolonged postoperative mechanical ventilation. Larger prospective studies in pediatric cardiac surgical patients are needed to confirm these results.
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