Subglottic stenosis in pregnancy: a case report

Introduction

Management of subglottic stenosis (SGS) in pregnancy is challenging. Currently, there is no consensus regarding optimal management, such that clinicians must base their approach on a few published case reports and their own limited experience.

Background

SGS is characterised by narrowing of the airway in the region below the vocal cords extending to the inferior margin of the cricoid cartilage (1). Aetiology is classified as either congenital, acquired or idiopathic. Acquired causes include systemic inflammatory or autoimmune diseases (such as granulomatosis with polyangiitis or sarcoidosis) and iatrogenic injury from treatments/interventions such as chemoradiotherapy or prolonged tracheal intubation (2). Where no underlying cause has been identified, SGS is considered idiopathic.

Symptoms of SGS can vary in severity, ranging from mild dyspnoea to life-threatening airway compromise. In pregnancy, due to the associated anatomical and physiological changes (which include increased oedema of airway tissues and increased oxygen utilisation), symptoms may present for the first time, or pre-existing symptoms can worsen. Operative intervention(s) may be required during pregnancy to avoid decompensation during labour and/or delivery. The surgical treatment of SGS in non-pregnant patients can require advanced airway management techniques; airway management in the pregnant patient, whether for treatment of disease progression or to facilitate obstetric surgery, is further complicated by the increased risk of oxygen desaturation (reduced oxygen reserve and increased utilisation), pulmonary aspiration and bleeding (from highly vascularised, congested tissues) (3).

Rationale and knowledge gap

Management of SGS in pregnancy poses significant challenges, including the potential for critical airway obstruction and the requirement for emergency airway intervention(s), during which airway management may be especially difficult. Currently, there is no consensus on the optimal strategies for maternal airway surgery or fetal delivery in pregnant patients with SGS, therefore clinicians must base their management strategies on just a few case reports/series. A scoping review conducted in 2023 (2) identified only 15 case reports/case series, with a total of just 27 cases. The review summarised common approaches to surgical intervention, anaesthetic management and delivery planning; however, the authors concluded that further evidence was needed to evaluate the safety and effectiveness of airway management strategies during pregnancy, as well as to compare the relative safety of vaginal versus caesarean delivery, to better inform clinical decision-making for both patients and clinicians.

Objective

We present three cases of patients with SGS in pregnancy who have varied presentations, clinical courses and treatment strategies, to provide clinicians with valuable insights and guidance in the management of these complex patients in order to optimise maternal and fetal outcomes. We present this article in accordance with the CARE reporting checklist (available at https://joma.amegroups.com/article/view/10.21037/joma-25-4/rc).

Case presentation

This is a retrospective, limited series of case reports that describes the varied presentations, clinical courses and management of three pregnant patients with SGS, including the differing approaches to operative management for therapeutic surgical interventions during the course of their pregnancies and the differing modes of fetal delivery employed for each patient.

Case 1 (delivery date: August 2017)

A 29-year-old multiparous woman with a body mass index (BMI) of 25 kg/m² who presented with idiopathic subglottic stenosis (SGS) for the first time.

She presented to her general practitioner with increasing dyspnoea during the first trimester. Initially, she was referred for urgent lung spirometry; however, subsequent flexible nasendoscopy (FNE) confirmed SGS with 70% stenosis requiring surgical intervention. Following the recommendation of the multidisciplinary team (MDT) of experienced Ear, Nose and Throat (ENT) surgeons, anaesthetists, obstetricians and midwives, she underwent successful balloon dilatation at 23 weeks gestation, under general anaesthesia. This was performed in the left lateral position, using an apnoeic oxygenation technique with high-flow nasal oxygen (HFNO), following our institution’s standardised technique (4). Her symptoms significantly improved following the dilatation procedure. After further MDT discussion, an elective caesarean delivery under regional anaesthesia was planned at 38+5 weeks gestation, with the intention of performing pre-operative FNE to guide perioperative airway management.

However, she presented three days before her planned surgery with spontaneous rupture of membranes (at 38+2 weeks gestation). FNE was reassuring, and she underwent uncomplicated category-3 caesarean delivery under spinal anaesthesia.

Case 2 (delivery date: September 2022)

A 38-year-old primigravida with a BMI of 26 kg/m² who had been previously diagnosed with idiopathic SGS. She had undergone multiple balloon dilatation procedures from the age of 25. At 10 weeks gestation, the obstetricians referred her for FNE due to worsening dyspnoea, which revealed 50% airway stenosis. The MDT decided to monitor closely and review the need for surgical intervention as the pregnancy progressed.

Repeat FNE during the second trimester revealed significant worsening of stenosis. She underwent successful balloon dilatation at 25 weeks gestation under general anaesthesia, in left lateral position, using an apnoeic oxygenation technique with HFNO (with continuous transcutaneous carbon dioxide monitoring—now available at our institution). Her symptoms significantly improved following the dilatation procedure. Further MDT review in the third trimester confirmed that she remained symptom-free, with stable peak expiratory flow measurements (previously shown to correlate well with disease progression in this patient). The MDT agreed that progression to term gestation, spontaneous labour and vaginal delivery would be safe (in keeping with the patient’s preference). An epidural in early labour was planned so that emergency caesarean or instrumental delivery could be undertaken without general anaesthesia (and airway management).

After a prolonged labour (with effective epidural analgesia), the patient underwent uneventful forceps-assisted delivery following epidural top-up at 40 weeks gestation.

Case 3 (delivery date: January 2023)

A 34-year-old primigravida with a BMI of 40 kg/m² who had developed SGS secondary to childhood chemoradiotherapy for lymphoma.

Prior to pregnancy, she had been undergoing regular, six-monthly balloon dilatation procedures. In the first trimester, she was referred to the high-risk obstetric anaesthetic clinic. Following MDT review, further surgery was planned at 22 weeks gestation with the aim of providing sufficient airway dilatation to avoid further intervention until post-partum. The procedure was performed uneventfully under general anaesthesia, in left lateral position. Due to her raised BMI, supraglottic low-frequency manual jet ventilation (via the surgical laryngoscope) was preferred to apnoeic oxygenation. There was immediate improvement in the patient’s symptoms following the dilatation procedure.

However, by the third trimester, her previously resolved symptoms of dyspnoea had returned, with the addition of stridor when lying flat and on minimal exertion—this was attributed to a combination of pregnancy-related tissue engorgement, a mild respiratory tract infection and compression from a large gravid uterus (fetus measuring 95th centile). The region of stenosis was too distal to be visualised on FNE, so this modality could not be used in the assessment of disease severity. Following MDT discussion of the risks/benefits of early caesarean delivery versus further surgical dilatation in late pregnancy, an elective caesarean delivery was undertaken at 37 weeks gestation.

Prior to surgery, intravenous dexamethasone and nebulised adrenaline were administered to reduce airway congestion and improve symptoms during supine/left lateral positioning. Anaesthesia was conducted successfully using a combined-spinal-epidural technique, with reduced spinal dose to minimise respiratory compromise. HFNO was delivered perioperatively, to reduce work of breathing, optimise oxygenation, and in preparation for conversion to general anaesthesia (not required). A comprehensive airway management strategy had been agreed, with the necessary equipment and personnel present.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from all the patients for publication of these case reports. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

Key findings

Presentation and symptom burden

All three patients reported significantly increased dyspnoea from the first trimester, which prompted referral to the ENT surgeons and the joint high-risk obstetric-anaesthetic clinic for evaluation. Early symptom recognition is key to diagnosis (if SGS is previously unknown) and assessment with both spirometry flow-volume loops and FNE is essential to differentiate pathological shortness of breath from normal physiological dyspnoea of pregnancy. After diagnosis of SGS, repeated assessment with FNE may provide valuable information, to guide the necessity/timing of any surgical intervention(s) in some patients.

Type and timing of surgical intervention

All three patients underwent elective/expedited balloon dilatation (to relieve airway narrowing) in the second trimester, between 20 and 25 weeks’ gestation.

Anaesthesia technique

Two patients underwent apnoeic oxygenation with HFNO and one patient underwent high-pressure jet ventilation for their balloon dilatation procedures, without incurring any complications. Continuous transcutaneous carbon dioxide monitoring was utilised during the second case that underwent apnoeic oxygenation, by which time the benefit of continuous carbon dioxide monitoring was better recognised (leading to the acquisition of such a device by our institution)—understanding that sustained hypercarbia should be avoided in order to reduce the risk of uterine irritability and possible pre-term labour. This illustrates the progression in our clinical management and the technological advancements over time.

Perioperative monitoring

Preoperative and postoperative fetal heart rate monitoring was undertaken in all three cases for the dilatation procedures (no concerning features reported). Continuous fetal heart monitoring was not used.

Mode of fetal delivery

Elective/expedited caesarean delivery was undertaken in two cases, to reduce the risk of emergency intervention requiring general anaesthesia; however, it was determined that it was safe to allow one patient to proceed with spontaneous labour.

MDT approach

All three cases were reviewed in-person at the joint high-risk obstetric-anaesthetic clinic on at least two occasions. These cases highlight the need for MDT involvement, to ensure shared decision-making and a cohesive approach to patient care, so that maternal and fetal outcomes can be optimised.

Strengths and limitations

Despite these patients demonstrating a range of presentations and aetiology, there are consistent themes in their management. The differing strategies employed for labour and delivery reinforces the need for an individualised approach.

Case 1 has previously been published as a stand-alone case report; however, its inclusion is merited in this series as it enables direct comparison with other cases conducted at the same institution, offering valuable insights into both the common themes and variations in management of SGS during pregnancy. As this was also the first case undertaken at our institution, its inclusion also helps to demonstrate the learning and progression of institutional practices, including the use of newly available technology such as the continuous transcutaneous carbon dioxide monitoring. We acknowledge that re-presenting a previously published case may be viewed as a limitation; however, we believe that its comparative value within the broader series justifies its inclusion.

We recognise that this is a limited series of case reports from a single centre, and therefore, any conclusions must be interpreted with caution. In addition, the retrospective nature of these case reports introduces inherent limitations, including the risk of bias due to reliance on existing medical records and the lack of standardised data collection. We aim to review and collect data on similar future cases managed at our institution, to improve the robustness of our recommendations.

Comparison with similar research

Presentation and symptom burden

Pregnancy is associated with physiological changes that can worsen symptoms of SGS, especially dyspnoea—increased total body water causes mucosal oedema of the vocal cords, larynx and trachea. In a survey-based study (5), 71% of patients with idiopathic SGS reported increased severity of airway symptoms during pregnancy.

Type and timing of surgical intervention

The most common surgery performed for airway stenoses in pregnancy is endoscopic balloon dilatation (rather than laser). This involves the passage of a tiny balloon on a guidewire into the area of stenosis via the surgeon’s suspension laryngoscope (under microscopic guidance), which is then inflated for 20–60 seconds, then deflated, with this process repeated up to five times to ensure maximal dilatation (2).

The second trimester is preferred for surgical interventions; the risk of spontaneous abortion is lower than the first trimester and rates of preterm delivery are lower than the third trimester (6); and the risk of oxygen desaturation and pulmonary aspiration is higher in the third trimester. The requirement and timing of surgery should be individualised and determined by the MDT, having fully appraised the risks/benefits to mother and fetus.

Explanation of findings

Anaesthesia technique

Two patients underwent apnoeic oxygenation with HFNO for their dilatation procedures. Our institution has extensive experience of apnoeic oxygenation in non-pregnant patients (4,7); this technique was preferred to jet ventilation or intermittent tracheal intubation due to technique familiarity, and the advantages of unobstructed surgical access, avoidance of barotrauma, and avoidance of bleeding from instrumentation of narrowed, engorged tissues (4). Nevertheless, there are several concerns/limitations surrounding its use in pregnancy:

Increased oxygen consumption and reduced functional residual capacity may reduce efficacy of preoxygenation and apnoeic oxygenation, increasing the risk of oxygen desaturation (6). Patients were placed in a head-elevated position to optimise oxygenation, and individualised rescue oxygenation strategies were in place (though not required, with SpO₂ maintained ≥94% in both cases, with apnoea times of 13 and 12 minutes, respectively).

Increased gastro-oesophageal reflux relating to progesterone-induced relaxation of the oesophageal sphincter and increased abdominal pressure from the gravid uterus, increases the risk of pulmonary aspiration in an unprotected airway (6). All three patients underwent preoperative fasting and were administered prophylactic medication (sodium citrate and/or proton pump inhibitor). There were no episodes of pulmonary aspiration.

When apnoeic oxygenation using HFNO was first described (8), a proposed benefit was attenuation of carbon dioxide accumulation; subsequent studies have demonstrated that the rate of arterial carbon dioxide accumulation is unaffected by oxygen flow rates (9). Carbon dioxide accumulation is of particular concern in pregnancy, since maternal hypercarbia may cause harmful acidosis in the fetus. Prolonged apnoea should be avoided and carbon dioxide monitoring ideally employed (transcutaneous carbon dioxide monitoring was not available at our institution for use in Case 1, but was available for use at the time of Case 2).

HFNO has been used safely during laser laryngotracheal surgery at some institutions; however it has also been associated with airway fire (10), such that it should be considered a relative contraindication. Though laser was not required in these cases, its use as an adjunct to balloon dilatation would have been precluded at our institution in combination with HFNO, such that an alternative oxygenation technique would have been selected in the event of laser use.

Jet ventilation was used for Case 3 due to her raised BMI and unfavourable body habitus for apnoeic oxygenation (perceived increased risk of oxygen desaturation). Given the brevity of the procedure, low-frequency manual jetting was deemed suitable; however, high frequency or double-jet (combined high and low frequency) ventilation may be preferable for longer procedures.

Perioperative monitoring

Continuous perioperative fetal monitoring is logistically difficult to achieve, and there is no clear evidence to support its use. The American College of Obstetricians and Gynecologists advises that fetal monitoring should be individualised and determined by the MDT (11). In line with these recommendations and the approach described in other case reports, only preoperative and postoperative fetal heart rate monitoring was undertaken (no concerning features reported).

Mode of fetal delivery

Elective/expedited caesarean delivery was preferred in two cases, to reduce the risk of emergency intervention requiring general anaesthesia (and challenging airway management); however, one case demonstrates that it may be safe to allow spontaneous labour (with an epidural), in select patients. In this case, peak expiratory flow measurements (as an indicator of disease progression) were helpful in decision-making, though this is not generally applicable. This highlights the importance of a well-coordinated MDT that enables individualised care to be delivered safely.

MDT approach

Early and continued involvement of experienced obstetricians, midwives, anaesthetists and surgeons is essential to ensure optimal assessment, planning and care during any surgical treatment(s), labour (if applicable) and delivery. These patients are high-risk and decisions are complex.

Implications and actions needed

Based upon our experience, considerations for management of SGS in pregnancy include:

• Prompt recognition and evaluation of symptoms in early pregnancy.
• Early referral to high-risk obstetric-anaesthetic clinic and ENT for assessment (including FNE).
• Comprehensive MDT discussion regarding requirement for (and timing of) surgical intervention(s), and individualised plan for remainder of pregnancy, labour and delivery.
• Surgical intervention (most likely balloon dilatation) undertaken in the second trimester, where required and possible.
• Consideration of apnoeic oxygenation with HFNO to facilitate surgery—with continuous carbon dioxide monitoring, if available (though clinicians should use the technique they are most familiar with).
• Fetal heart rate monitoring pre- and post-procedure.
• Regular post-dilatation MDT review.
• Consideration of elective caesarean delivery to avoid emergency airway management (though the approach to labour and delivery should be patient-specific).

Conclusions

This retrospective case report of three pregnant patients with SGS highlights the importance of early involvement and continued combined input from anaesthetists, midwives, obstetricians and surgeons so that decisions regarding the requirement/timing of operative dilatation procedures during pregnancy and the timing/mode of fetal delivery can be made safely, minimising the need for emergency airway interventions in patients with challenging airways. Both apnoeic oxygenation with HFNO and high-pressure jet ventilation were used safely to facilitate surgery in these patients, who all underwent balloon dilatation procedures during their second trimester.

Acknowledgments

One of the cases (Case 1) has been published previously as a stand-alone case report: Bourn S, Milligan P, McNarry AF. Use of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) to facilitate the management of subglottic stenosis in pregnancy. Int J Obstet Anesth 2020;41:108-13.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://joma.amegroups.com/article/view/10.21037/joma-25-4/rc

Peer Review File: Available at https://joma.amegroups.com/article/view/10.21037/joma-25-4/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://joma.amegroups.com/article/view/10.21037/joma-25-4/coif). P.A.W. serves as an unpaid editorial board member of Journal of Oral and Maxillofacial Anesthesia from June 2022 to December 2025. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from all the patients for publication of these case reports. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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