Difficult ventilation in a patient with a giant aortic aneurysm: A challenge for the anesthesiologist

Patients with Marfan syndrome present anatomic variations that may increase the risk of a difficult airway. Moreover, they can present large aortic aneurysms, which may cause extrinsic airway compression. Therefore, difficult ventilation during general anesthesia poses a challenge in that the anesthesiologist has to promptly make a crucial differential diagnosis. Multidisciplinary preoperative assessment and planning of the airway and ventilation management are of utmost importance in such uncommon and highly complex clinical cases. Fiberoptic bronchoscopy is probably a really useful tool in order to assess the severity and extent of the airway compression, both preoperatively and intraoperatively. We present a clinical case where difficult ventilation occurred immediately after the induction of general anesthesia.

Keywords: Airway obstruction, aortopexy, difficult ventilation, large aortic aneurysm, mediastinal mass syndrome

How to cite this article:
Montane-Muntane M, Ascaso M, Rivera-Vallejo L, Navarro-Ripoll R. Difficult ventilation in a patient with a giant aortic aneurysm: A challenge for the anesthesiologist. Ann Card Anaesth 2023;26:86-9
How to cite this URL:
Montane-Muntane M, Ascaso M, Rivera-Vallejo L, Navarro-Ripoll R. Difficult ventilation in a patient with a giant aortic aneurysm: A challenge for the anesthesiologist. Ann Card Anaesth [serial online] 2023 [cited 2023 Jan 4];26:86-9. Available from: https://www.annals.in/text.asp?2023/26/1/86/367020

Introduction

Patients with Marfan syndrome present anatomic variations that may increase the risk of a difficult airway.[1] These variations range from high arched palate to increased thyromental distance, potential cervical spine instability, and temporomandibular joint laxity that can lead to dislocation, among others. Moreover, patients with Marfan syndrome can present large aortic aneurysms, which may cause extrinsic airway compression. Additionally, some of them have bullous lung disease with a history of recurrent pneumothorax.[2] Therefore, difficult ventilation during general anesthesia poses a challenge in that the anesthesiologist has to promptly make a crucial differential diagnosis. We present a clinical case where difficult ventilation occurred immediately after the induction of general anesthesia.

Case Report

A 16-year-old male with Marfan syndrome (who consented to this report) presented to the preoperative anesthesia clinic proposed to undergo a reintervention for a surgical repair of a large ascending aortic aneurysm with chronic dissection. The patient had a cardiac history consisting of a mechanical Bentall procedure performed in another center at the age of 8.

As per the other Marfan's complications, the patient presented lens subluxation, pectus carinatum, moderate scoliosis, and a history of bilateral spontaneous pneumothorax due to bullae.

The physical examination revealed a young asthenic male (height 196 cm, weight 60 kg, BMI 15.6 kg/m2), his saturation on room air was 100%. The previous anesthetic records exposed a Cormack–Lehane grade 2 view through a direct laryngoscopy. A computed tomography (CT) scan revealed an ascending aortic aneurysm (94 mm × 78 mm) that extended along 10 cm starting at 25 mm from the aortic ring, exactly where the previous Dacron graft ended. The large ascending aortic aneurysm caused an extrinsic compression of the distal trachea (minimum anteroposterior diameter of 2 mm) and displaced the pulmonary artery leftward [Figure 1]a, [Figure 1]b, [Figure 1]c. The patient denied any symptoms of airway obstruction neither in an upright position nor in a supine or recumbent position. The CT also revealed the adhesion of the aortic aneurysm wall to the internal table of the sternum. Therefore, as an aortic rupture during re-sternotomy was highly expected, the surgical team planned to proceed with femoral cannulation, under general anesthesia, to establish cardiopulmonary bypass (CPB) and achieve deep hypothermia before starting the re-sternotomy. The remainder of his examinations and medical history were unremarkable.

Figure 1: Preoperative and postoperative imaging. (a) A preoperative chest X-ray shows moderate scoliosis and an enlarged cardiac silhouette due to the aortic aneurysm shadow. (b) A preoperative computed tomography (CT) scan clip shows a large ascending aortic aneurysm (94 mm × 78 mm), closely related to the internal table of the sternum. In the back of the aneurysm, the distal trachea is partially occluded due to external compression (white arrow). (c) A preoperative CT 3D reconstruction reveals an aneurysm that extends through the ascending aorta to the arch with evident aneurysmal dilation of both coronary ostia. (d) A postoperative CT clip shows the relief of the airway compression (white arrow) by the replacement of the aneurysm with a tube graft along with the aortopexy

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On the day of the elective surgery, the patient was taken to the cardiac operating room (OR) and transferred to the OR table in a supine position, without presenting any symptoms of airway obstruction. Given that a difficult airway was expected, the difficult airway trolley was present in the OR. Anxiolysis was achieved with 2 mg of intravenous midazolam. Standard monitoring, left radial arterial cannula, processed Electroencephalogram (EEG) (BISTM, Medtronic, Minneapolis, MN, USA), and bilateral non-invasive near-infrared spectroscopy tissue oximetry (INVOS 5100CTM, Medtronic, Minneapolis, MN, USA) were placed. General anesthesia was then induced with 1 mg/kg lidocaine, 2.5 μg/kg fentanyl, 2 mg/kg propofol, and 0.6 mg/kg rocuronium. After the induction, facial mask ventilation with a Guedel cannula was not successful: neither capnography nor chest excursion were obtained. Direct laryngoscopy was performed and a 7.5 mm endotracheal tube (ETT) was placed (Cormack–Lehane 2B), however, no effective ventilation was accomplished, there was no capnography, and the peripheral oxygen saturation (SpO2) fell to 75%. An esophageal placement of the tube was suspected, so it was removed and a laryngeal mask was placed. Ventilation was acceptable and the SpO2 rose to 100%, at the expense of very high airway pressures. Fiberoptic intubation was performed and a 7 mm ETT was placed, an extrinsic compression of the carina was visualized distal to the tip of the ETT, which occluded the tracheal lumen almost completely and was accompanied by tracheomalacia [Figure 2]a. Lung ventilation became extremely difficult; it slightly improved with a ventilatory strategy of low tidal volume, high respiratory rate, and high positive end-expiratory pressure (14 cm H2O). The suboptimal ventilation of the patient caused severe hypercapnia (EtCO2 85 mmHg and PaCO2 93 mmHg), which induced heart rhythm disturbances without hemodynamic instability. Given the severity of the scenario, the previously planned femoral arterial and venous cannulas were rapidly inserted and CPB was established uneventfully, temporarily solving the ventilation problems. A left ventricular vent cannula was placed through the apex using a left mini-thoracotomy. Once deep hypothermia (18°C) was achieved, the surgical team started the re-sternotomy. This finally caused the rupture of the large aneurysm and circulatory arrest was induced. The mediastinal dissection was completed and unilateral antegrade cerebral perfusion was initiated through the brachiocephalic trunk (BCT). The surgical team proceeded with an ascending aorta and arch replacement with a 26 mm Hemashield tube graft and reimplantation of the BCT and left common carotid using a bifurcated prosthesis (12 and 8 mm, respectively). Finally, the ascending aortic graft was wrapped with the remains of the ascending aortic aneurysm tissue as an aortopexy to decompress the trachea and definitively solve the ventilatory problem [Figure 3], [Figure 1]d. The intraoperative fiberoptic bronchoscopy (FOB) confirmed a significant improvement in the diameter of the trachea after the aortopexy [Figure 2]b. The circulatory arrest, aortic cross-clamp, and CPB times were 35, 77, and 217 min, respectively. The patient was uneventfully extubated in the intensive care unit during the first postoperative day and was discharged on the eighth postoperative day.

Figure 2: Intraoperative fiberoptic bronchoscopy. (a) The tracheal lumen, at the level of the carina, is almost completely occluded due to the extrinsic compression by the aneurysm. (b) Relief of the airway compression after the aortopexy

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Figure 3: Surgical view of the aortopexy. The remains of the aortic aneurysm tissue surround the aortic graft to bring the aorta away from the airway toward the sternum, thereby, increasing the airway lumen

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Discussion

Perioperative mediastinal mass management is an anesthetic challenge. The lack of clinical guidelines, the relative scarcity of cases, and the heterogeneity between them are the main reasons that make the safe conduct of anesthesia highly complex.[3]

There are previous case reports where patients with a tracheal mass are placed in femoro-femoral bypass before general anesthesia but patients always presented airway obstruction symptoms.

In this report, we presented a case of difficult ventilation in which a wide differential diagnosis has to be made, following always a safety algorithm. First, the airway must be secured and the correct placement of the ETT has to be confirmed. In our first intubation attempt, the absence of capnography could be mainly due to three reasons: an esophageal placement of the ETT, the airway obstruction caused by the large aortic aneurysm, or a tension pneumothorax. FOB could have been useful if an extrinsic airway compression had been suspected and also to rule out esophageal intubation. While in the OR, we discarded the possibility of an extrinsic airway compression given that we thought that we could find difficulty in the ventilation but not an absolute impossibility of ventilation. A tension pneumothorax caused by the rupture of bullae would have been accompanied by hemodynamic instability. Moreover, tension pneumothorax is uncommon and is not usually produced right after the induction of anesthesia. Nevertheless, we decided to follow the difficult airway management algorithm[4] and place a third-generation laryngeal mask which enabled sufficient ventilation to prevent hypoxemia at the expense of high airway pressures. Besides, the difficult airway guidelines, we deem alternative approaches to also be suitable in this context, given the peculiarity of the clinical scenario.

Once the airway was secured, FOB was fundamental to diagnose the cause of the difficult ventilation. Worth noting, the obstruction was distal, right at the carina, and its management was, therefore, particularly challenging. The use of high PEEP enabled the maintenance of a narrow passage; otherwise, the extrinsic compression would totally collapse the airway through which ventilation was possible even though hypercapnia rapidly developed. The placement of a long ETT or an endobronchial tube in order to bypass the obstruction implies risks such as airway damage and aneurysm rupture.[5] Cannulation under sedation and local anesthesia has been described in similar cases of airway obstruction and it would have been an interesting option given that the surgical plan was to establish CPB before the re-sternotomy.[6] The absence of the symptoms of airway compression due to the patient's capacity to maintain a patent airway by the exertion of high negative pressure clearly led to an underestimation of the preoperative risk. The patient was not placed on CPB under sedation before the induction of general anesthesia because we guided our performance, our anesthetic plan, by the lack of airway obstruction symptoms.

In our clinical case, the ventilation problem was at first temporarily tackled by the initiation of CPB and it was finally solved by the performance of an aortopexy, which allowed uneventful early extubation. The use of this surgical technique is considered to be the cornerstone in order to avoid postoperative complications related to tracheomalacia.[7]

Multidisciplinary preoperative assessment and planning of the airway and ventilation management are of utmost importance in such uncommon and highly complex clinical cases. FOB is probably a really useful tool to assess the severity and extent of airway compression, both preoperatively and intraoperatively.[8] We conclude that the absence of airway obstruction symptoms is not a good indicator of easy ventilation, given that it can lead to an underestimation of the risks.[5] We truly believe that a standardized assessment and planning performed by a multidisciplinary team would reduce the odds of life-threatening complications during perioperative care.[5]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.Child AH. Non-cardiac manifestations of Marfan syndrome. Ann Cardiothorac Surg 2017;6:599-609.

2.Judge DP, Dietz HC. Marfan's syndrome. Lancet 2005;366:1965-76.

3.Blank RS, de Souza DG. Anesthetic management of patients with an anterior mediastinal mass: Continuing professional development. Can J Anaesth 2011;58:853-67.

4.Frerk C, Mitchell VS, McNarry AF, Mendonca C, Bhagrath R, Patel A, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015;115:827-48.

5.Erdös G, Tzanova I. Perioperative anaesthetic management of mediastinal mass in adults. Eur J Anaesthesiol 2009;26:627-32.

6.Malpas G, Hung O, Gilchrist A, Wong C, Kent B, Hirsch G, et al. The use of extracorporeal membrane oxygenation in the anticipated difficult airway: A case report and systematic review. Can J Anaesth 2018;65:685-97.

7.Jennings RW, Hamilton TE, Smithers CJ, Ngerncham M, Feins N, Fokeer JE. Surgical approaches to aortopexy for severe tracheomalacia. J Pediatr Surg 2014;49:61-6.

8.Kumar A, Dutta V, Negi S, Puri GD. Vascular airway compression management in a case of aortic arch and descending thoracic aortic aneurysm. Ann Card Anaesth 2016;19:568-71.