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Table of Contents
CASE REPORT  
Year : 2014  |  Volume : 17  |  Issue : 4  |  Page : 302-305
Severe tracheobronchial compression in a patient with Turner's syndrome undergoing repair of a complex aorto-subclavian aneurysm: Anesthesia perspectives


1 Department of Anesthesiology, Division of Cardiac Anesthesiology and Critical Care Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
2 Department of Radiology, Division of Cardiac Imaging, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
3 Department of Surgery, Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, Ontario, Canada

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Date of Submission23-Feb-2014
Date of Acceptance17-Aug-2014
Date of Web Publication1-Oct-2014
 

   Abstract 

We present a case of severe tracheobronchial compression from a complex aorto-subclavian aneurysm in a patient with Turner's syndrome undergoing open surgical repair. Significant airway compression is a challenging situation and requires careful preoperative preparation, maintenance of spontaneous breathing when possible, and consideration of having an alternative source of oxygenation and circulation established prior to induction of general anesthesia. Cardiopulmonary monitoring is essential for safe general anesthesia and diagnosis of unexpected intraoperative events.

Keywords: Aortic aneurysm; Cardiopulmonary bypass; Cerebral oximetry; Spontaneous ventilation; Turner′s syndrome

How to cite this article:
Hudson CC, Stewart J, Dennie C, Malas T, Boodhwani M. Severe tracheobronchial compression in a patient with Turner's syndrome undergoing repair of a complex aorto-subclavian aneurysm: Anesthesia perspectives. Ann Card Anaesth 2014;17:302-5

How to cite this URL:
Hudson CC, Stewart J, Dennie C, Malas T, Boodhwani M. Severe tracheobronchial compression in a patient with Turner's syndrome undergoing repair of a complex aorto-subclavian aneurysm: Anesthesia perspectives. Ann Card Anaesth [serial online] 2014 [cited 2020 Mar 31];17:302-5. Available from: http://www.annals.in/text.asp?2014/17/4/302/142071



   Introduction Top


An aortic aneurysm is a localized or diffuse dilatation of the aorta, which can be life-threatening if left untreated. Indications for repair - by open surgical technique or endovascular stent grafting - include size, presence of connective tissue disease, strong family history, and symptoms. We present a case of severe tracheobronchial compression from a complex aorto-subclavian aneurysm in a patient with Turner's syndrome undergoing open surgical repair with deep hypothermic circulatory arrest (DHCA). We highlight the challenges and considerations of this complex problem including cardiopulmonary bypass (CPB), spontaneous ventilation, lung isolation, and monitoring including transesophageal echocardiography (TEE), cerebral oximetry, and arterial pressure monitoring.


   Case report Top


A 27-year-old woman with Turner's syndrome presented for repair of complex proximal descending aorto-subclavian aneurysm (Crawford Type II). She initially presented 2 months prior with new onset left-sided neck and shoulder pain with weakness. Computerized tomography (CT) scan revealed a large proximal thoracic aortic aneurysm (TAA) measuring 8.0 cm × 5.5 cm involving her left subclavian artery [Figure 1]. In addition, she had an aberrant right subclavian artery that originated from the aneurysm and took a retro-esophageal and retro-tracheal course. Though asymptomatic from a respiratory standpoint, CT scan demonstrated significant airway compression: The carina was compressed to 3.9 mm and the left main bronchus to 1.6 mm [Figure 2]. Contrary to the imaging, flow-volume loops were normal and pulmonary functions showed forced expiratory volume in 1 second 3.05 L (99% predicted), forced vital capacity 3.47 L (112% predicted), and total lung capacity 4.64 L (111% predicted).
Figure 1: Three-dimensional surface-shaded computerized tomography reconstruction of the aorta reveals a common origin of the right and left common carotid arteries from the aortic arch (black arrow) in (a). Note the aneurysmal dilatation of an aberrant right subclavian artery (white arrowhead) from the proximal descending aorta in the antero-posterior projection in (a), right anterior oblique in (b) and posterior (c) projections. There is also aneurysmal dilation of the left subclavian artery (white arrow)

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Figure 2: Prospective electrocardiogram gated axial computerized tomography angiogram reveals an aneurysmal left subclavian and aberrant right subclavian arteries (white arrow). Note the marked compression of the carina as a result of the aneurysm (black arrow)

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The surgical plan consisted of right carotid-axillary bypass followed by a descending aortic replacement under DHCA via left thoracotomy. In addition to her tracheobronchial compression from the aneurysm, the patient also had nonreassuring airway features (Mallampati 3, short thyromental distance, and limited range of motion of the neck) associated with Turner's syndrome. With significant potential for catastrophic airway compromise, we elected to cannulate the femoral artery and vein under subarachnoid block (SAB) prior to induction of general anesthesia. The SAB was placed with the patient in a sitting position, with a 25 gauge pencil point needle at the L3/L4 level: 10 mg of isobaric bupivacaine and 25 μg fentanyl were administered. Thereafter, under awake fiberoptic bronchoscopy (FOB), an armored 6.0 mm endotracheal tube was placed above the level of tracheal compression [Figure 3]. FOB examination showed dynamic motion of the trachea with worsening compression during inspiration. Anesthesia was induced with inhalational sevoflurane supplemented with intravenous agents, and spontaneous breathing was maintained during the carotid-axillary bypass graft portion of the surgery. Monitors included both upper and lower body invasive arterial blood pressure monitored via the right radial and femoral arteries, continuous cardiac output and mixed venous oxygen saturation monitoring via a pulmonary artery catheter, Bispectral Index (BIS™), and Cerebral/Somatic Oximetry INVOS ® . TEE was not inserted because of the possibility of worsening airway compression and the proximity of the aneurysm to the esophagus. The patient remained hemodynamically stable. Upon initiation of CPB, the patient was paralyzed with rocuronium: The aim of delaying muscle paralysis was to determine whether her dynamic airway compression would cause significant problems with positive pressure ventilation upon disengagement of CPB. The patient tolerated positive pressure ventilation. Upon the initiation of CPB, the right radial arterial pressure plummeted (right femoral arterial pressure remained normal), with concomitant decrease of bilateral cerebral oximetry values and mixed venous oxygen desaturation. The patient was immediately separated from CPB, and the desaturations and upper extremity blood pressure quickly recovered. To help delineate the reason for the physiological changes, a TEE was carefully inserted, revealing an undiagnosed Stanford Type B dissection [Figure 4]. We hypothesized that the false lumen of the dissection had been unknowingly cannulated by the femoral arterial CPB cannula. The procedure was abandoned for further work-up.
Figure 3: Fiberoptic bronchscopic image of the airway compression at the level of the carina during inspiration

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Figure 4: Transesophageal echocardiography image of the ascending aorta in the mid-esophageal short axis view with color Doppler. Note the intimal dissection fl ap with communication (white arrow) between the true and false lumens

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CT scan confirmed the new diagnosis of a dissection immediately distal to the aorto-subclavian aneurysm extending into the common iliac arteries [Figure 5]. Several days later, she returned for completion of her surgery. CPB was performed via direct ascending aortic and right atrial cannulation. As before, an awake fiberoptic intubation was performed. Because of dynamic airway knowledge obtained earlier, the patient was paralyzed on induction and a 7.0 mm Univent™ bronchial blocker was placed for lung isolation. The patient underwent successful repair of the aneurysm and Type B dissection, and had an uneventful recovery.
Figure 5: Three-dimensional surface-shaded computerized tomography (CT) reconstructions of the thoracic aorta in the antero-posterior projection (a) and lateral (b) projections reveal a dissection of the descending aorta (white arrows) below the subclavian artery aneurysms (white arrowheads). A corresponding sagittal reformatted image from the CT angiogram shows the aneurysm (black arrowhead) and dissection (black arrows) in (c)

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   Discussion Top


Turner's syndrome is characterized by the absence of all or a component of a second sex chromosome. [1] The prevalence of congenital heart disease is as high as 45% with coarctation of the aorta and bicuspid aortic valve being the most common structural problems. [2] Aortic dilatation is also associated with Turner's syndrome with numerous case reports of dissection. [2] In addition to Turner's syndrome, the patient had several complexities: Difficult airway, upper-airway compression, need for lung isolation, and a complex aorto-subclavian aneurysm. We also encountered an unusual intraoperative complication and diagnostic dilemma. Complex patients with complex pathology require careful planning and investigations to ensure an optimal outcome.

The biggest challenge for us was induction and maintenance of anesthesia in a patient with severe airway compression at risk of fatal obstruction. Patients with central airway obstruction requiring general anesthesia need a careful preoperative assessment. [3] Signs or symptoms of cardiorespiratory compromise include dyspnea, orthopnea, stridor, syncope, chest discomfort, cough, hoarseness, dysphagia, and superior vena cava obstruction. CT scan is essential to demonstrate the location and extent of the airway compromise. A 50% decrease in tracheobronchial lumen - either diameter or cross-sectional area - is associated with a greater risk of respiratory complications during general anesthesia. [4] Flow-volume loops are commonly ordered: Patients with intra-thoracic airway obstruction typically have a reduced expiratory flow rate, while patients with extra-thoracic airway obstruction typically have a reduced inspiratory flow rate. [5] Our patient had normal flow-volume loops: Current practice guidelines do not recommend routine spirometric testing as they are unreliable to detect dynamicity, severity, and site of airway obstruction. [3] A recent study evaluating 475 consecutive spirometries performed at a pulmonary function laboratory reached similar conclusions: All diagnostic criteria for detecting upper airway obstruction had low sensitivity. [6]

Where significant tracheobronchial compression is present, maintaining spontaneous ventilation with continuous hemodynamic and respiratory monitoring is essential. [3] In this case, we performed awake FOB - guided intubation and placed a small armored tube above the area of compression. The FOB allowed us to visualize the compression, determine whether it was dynamic or static with respiration, and ensure that we did not disturb it, causing edema and reduced luminal size. We maintained spontaneous breathing with volatile anesthetic and carefully titrated intravenous opioids. Our plan was to avoid lung isolation and administration of muscle relaxants until initiation of CPB. If muscle relaxants were required during the initial phase of the procedure, we would have used succinylcholine and manually assisted ventilation to assure that positive pressure ventilation could be tolerated. If airway obstruction did occur or we needed left lung isolation urgently, our plan was to immediately proceed to CPB.

Induction of general anesthesia in patients with severe positional symptoms due to airway compression is challenging even with maintenance of spontaneous ventilation, unless an alternative technique to maintain oxygenation and/or circulation (extracorporeal membrane oxygenation or CPB) has been established. Therefore, we prepared the patient for CPB prior to inducing general anesthesia. Heparinization, vein and artery isolation, and cannulation take time and establishment of CPB may not occur in time to prevent adverse outcomes unless prior preparations are made. We administered a SAB for femoral artery and vein cannulation, providing good analgesia for the procedure while maintaining an awake, spontaneously breathing patient. [7] Another option would have been to use local infiltration. Regarding the safety of SAB in the presence of heparinization, a meta-analysis in 2009 [8] of a total of 1106 patients and an academic institutions' experience of 10,000 cases found that SABs are safe for cardiac surgery prior to full heparinization. [9]

The intraoperative sequelae demonstrated the importance of appropriate intraoperative monitors. Measuring right upper extremity perfusion is critical for complicated cases, particularly aortic cases requiring peripheral cannulation. When femoral cannulation is utilized, it is imperative to have monitors measuring the perfusion of the head and upper body. Right radial arterial pressure monitoring ensures that perfusion is occurring at least to the level of the aortic arch vessels. However, this does not ensure perfusion to the brain: With regards to aortic dissection, the carotid arteries may originate from the false lumen. There are various case reports describing how cerebral oximetry has identified and prevented catastrophic events that would not otherwise have been detected in a timely fashion. [10] In our case, the right radial arterial pressure damping and cerebral oximetry desaturation helped us quickly identify that there was a problem with cannulation, allowing us to address it immediately and avoid a potential anoxic brain injury.

To summarize, significant airway compression from a TAA can be a challenging situation. Its management requires careful preoperative evaluation and planning including imaging studies, maintenance of spontaneous breathing when possible, and consideration of having an alternative source of oxygenation and circulation established prior to general anesthetic induction. Furthermore, appropriate cardiopulmonary monitoring and vigilance is essential for safe induction and maintenance of general anesthesia, as well as for identification and diagnosis of unexpected intraoperative events.

 
   References Top

1.Elsheikh M, Dunger DB, Conway GS, Wass JA. Turner's syndrome in adulthood. Endocr Rev 2002;23:120-40.  Back to cited text no. 1
    
2.Sybert VP, McCauley E. Turner's syndrome. N Engl J Med 2004;351:1227-38.  Back to cited text no. 2
    
3.Slinger P. Management of the patient with a central airway obstruction. Saudi J Anaesth 2011;5:241-3.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
4.King DR, Patrick LE, Ginn-Pease ME, McCoy KS, Klopfenstein K. Pulmonary function is compromised in children with mediastinal lymphoma. J Pediatr Surg 1997;32:294-9.  Back to cited text no. 4
    
5.Miller RD, Hyatt RE. Evaluation of obstructing lesions of the trachea and larynx by flow-volume loops. Am Rev Respir Dis 1973;108:475-81.  Back to cited text no. 5
[PUBMED]    
6.Modrykamien AM, Gudavalli R, McCarthy K, Liu X, Stoller JK. Detection of upper airway obstruction with spirometry results and the flow-volume loop: A comparison of quantitative and visual inspection criteria. Respir Care 2009;54:474-9.  Back to cited text no. 6
    
7.Chiu CL, Teh BT, Wang CY. Temporary cardiopulmonary bypass and isolated lung ventilation for tracheal stenosis and reconstruction. Br J Anaesth 2003;91:742-4.  Back to cited text no. 7
    
8.Zangrillo A, Bignami E, Biondi-Zoccai GG, Covello RD, Monti G, D'Arpa MC, et al. Spinal analgesia in cardiac surgery: A meta-analysis of randomized controlled trials. J Cardiothorac Vasc Anesth 2009;23:813-21.  Back to cited text no. 8
    
9.Kowalewski R, Seal D, Tang T, Prusinkiewicz C, Ha D. Neuraxial anesthesia for cardiac surgery: Thoracic epidural and high spinal anesthesia-why is it different? HSR Proc Intensive Care Cardiovasc Anesth 2011;3:25-8.  Back to cited text no. 9
    
10.Bar-Yosef S, Sanders EG, Grocott HP. Asymmetric cerebral near-infrared oximetric measurements during cardiac surgery. J Cardiothorac Vasc Anesth 2003;17:773-4.  Back to cited text no. 10
    

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Correspondence Address:
Christopher C .C. Hudson
Division of Cardiac Anesthesiology and Critical Care Medicine, University of Ottawa Heart Institute, 40 Ruskin Street H2410, Ottawa, Ontario K1Y 4W7
Canada
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-9784.142071

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

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