Mask induction with sevoflurane in a parturient with severe tracheal stenosis

Subglottic tracheal stenosis complicating pregnancy: A case report

The case presented details an uncommon case of subglottic tracheal stenosis exacerbated by pregnancy. We outine the multidisciplinary management involved and the outcomes for the pregnancy. The case serves as a reminder that shortness of breath in pregnancy has a broad differential diagnosis, and stridor is always abnormal.

Transnasal Humidified Rapid Insufflation Ventilatory Exchange in Laryngotracheal Resection and Reconstruction: A Report of Two Pregnant Cases

Introduction

The incidence of tracheal stenosis is progressively increasing. A risk factor for developing this clinical condition is a history of prolonged endotracheal intubation. A transnasal humidified rapid insufflation ventilatory exchange, known as THRIVE, has gained importance in tracheal resection surgeries.

Case Presentation

Herein, we describe the anesthetic management of two obstetric patients, a 19-year-old and 29-year-old, with a history of prolonged endotracheal intubation and a diagnosis of tracheal stenosis. The patients required the resection of the tracheal segment and end-to-end anastomosis. The anesthetic management focused on THRIVE using a high-flow nasal cannula.

Conclusions

This system proved to be a safe anesthetic technique for pregnant women and the fetus. Furthermore, it allowed surgeons to better visualize the surgical field without the risk of accidental injury to the endotracheal tube.

Endoscopic management of idiopathic subglottic stenosis in pregnancy

Aims

To describe the use of laser, endoscopic balloon dilatation with jet ventilation anaesthesia in the treatment of pregnant women with idiopathic subglottic stenosis.

Materials and methods

This is a case review of pregnant women with idiopathic subglottic stenosis, presenting to a tertiary referral centre with worsening breathlessness. Data were extracted from patient case notes.

Results

Four women underwent surgical management of subglottic stenosis in pregnancy. One patient required two procedures during the course of their pregnancy due to restenosis. All women had improvement in symptoms post-operatively and went on to deliver healthy babies at term.

Conclusion

Endoscopic balloon dilatation of idiopathic subglottic stenosis is a safe and viable treatment option in pregnancy and should be offered as first-line treatment in symptomatic women.

Pregnancy-associated idiopathic laryngotracheal stenosis: presentation, management and results of surgical treatment

OBJECTIVES

Idiopathic laryngotracheal stenosis (ILTS) is an uncommon problem arising mostly in women. In some, it arises during or is exacerbated by pregnancy. Experience with management of patients with this rare association is limited. This study seeks to evaluate the management of patients with pregnancy-associated ILTS and compare outcomes to cases not associated with pregnancy.

METHODS

Retrospective review of 15 patients undergoing surgical treatment of pregnancy-associated ILTS from 1971 to 2013. Variables of interest and airway outcomes were compared to patients with non-pregnancy-associated ILTS.

RESULTS

Pregnancy-associated ILTS was observed in 15/263 (5.7%) patients. Symptoms developed during their first pregnancy. When compared to non-pregnancy patients, these patients were younger (37 vs 47 years; P = 0.0003), had more prior tracheostomies (26.7% vs 10.9%; P = 0.085) and had more preoperative airway dilatations (86.7% vs 57.7%; P = 0.030). All patients completed pregnancy without complications and ultimately underwent laryngotracheal resection. The expression of hormonal receptors in the surgical specimens was similar in both groups (oestrogen receptors: 100% vs 75% and progesterone receptors: 71.4% vs 72.1%, in pregnancy and non-pregnancy patients, respectively). Airway outcomes were good/excellent in 13 (86.7%) patients with pregnancy-associated ILTS and 225 (90.7%) patients without pregnancy association (P = 0.642), and did not change when adjusting for other risk factors.

CONCLUSIONS

Pregnancy-associated ILTS is rare. The pathophysiology is unclear, but appearance of symptoms during pregnancy may suggest hormonal factors. To minimize foetal risk, dilatation during pregnancy followed by laryngotracheal resection after delivery is the preferred treatment. Pregnancy association does not seem to affect outcomes with expected satisfactory results in most patients.

Management of subglottic stenosis in pregnancy using advanced apnoeic ventilatory techniques

Objective

To describe the use of balloon dilation with non-invasive ventilation in the treatment of pregnant patients with idiopathic subglottic stenosis.

Methods

The medical charts of four consecutive patients who underwent jet ventilation or high-flow nasal cannula oxygenation with balloon dilation for the treatment of idiopathic subglottic stenosis during pregnancy were reviewed.

Results

Objective improvement of subglottic stenosis was seen in all four cases, with end-result Myer–Cotton grade 1 lesions down from pre-procedure grade 3 lesions. Patients also reported subjective improvements in symptomatology, with no further airway issues. All patients delivered normally, at term.

Conclusion

Laryngeal dilation with continuous radial expansion pulmonary balloons using non-invasive ventilation for the treatment of idiopathic subglottic stenosis in pregnant patients is safe and efficacious, and should be the first line treatment option for this patient population. The improvement in symptoms, and lack of labour and pregnancy complications, distinguish this method of treatment from others reported in the literature.

Subglottic Tracheal Stenosis in Pregnancy: Anaesthetic Implications

We present the first reported case of a pregnant patient with severe subglottic tracheal stenosis who required elective surgical tracheostomy prior to administration of labour analgesia.

Incomplete Spontaneous Recovery from Airway Obstruction During Inhaled Anesthesia Induction: A Computational Simulation

BACKGROUND

Inhaled induction with spontaneous respiration is a technique used for difficult airways. One of the proposed advantages is if airway patency is lost, the anesthetic agent will spontaneously redistribute until anesthetic depth is reduced and airway patency can be recovered. There are little and conflicting clinical or experimental data regarding the kinetics of this anesthetic technique. We used computer simulation to investigate this situation.

METHODS

We used GasMan, a computer simulation of inhaled anesthetic kinetics. For each simulation, alveolar ventilation was initiated with a set anesthetic induction concentration. When the vessel-rich group level reached the simulation specified airway obstruction threshold, alveolar ventilation was set at 0 to simulate complete airway obstruction. The time until the vessel-rich group anesthetic level decreased below the airway obstruction threshold was designated time to spontaneous recovery. We varied the parameters for each simulation, exploring the use of sevoflurane and halothane, airway obstruction threshold from 0.5 to 2 minimum alveolar concentration (MAC), anesthetic induction concentration 2 to 4 MAC sevoflurane and 4 to 6 MAC halothane, cardiac output 2.5 to 10 L/min, functional residual capacity 1.5 to 3.5 L, and relative vessel-rich group perfusion 67% to 85%.

RESULTS

In each simulation, there were 3 general phases: anesthetic wash-in, obstruction and overshoot, and then slow redistribution. During the first 2 phases, there was a large gradient between the alveolar and vessel-rich group. Alveolar do not reflect vessel-rich group anesthetic levels until the late third phase. Time to spontaneous recovery varied between 35 and 749 seconds for sevoflurane and 13 and 222 seconds for halothane depending on the simulation parameters. Halothane had a faster time to spontaneous recovery because of the lower alveolar gradient and less overshoot of the vessel-rich group, not faster redistribution. Higher airway obstruction thresholds, decreased anesthetic induction, and higher cardiac output reduced time to spontaneous recovery. To a lesser effect, decreased functional residual capacity and the decreased relative vessel-rich groups' perfusion also reduced the time to spontaneous recovery.

CONCLUSIONS

Spontaneous recovery after complete airway obstruction during inhaled induction is plausible, but the recovery time is highly variable and depends on the clinical and physiologic situation. These results emphasize that induction is a non-steady-state situation, thus effect-site anesthetic levels should be modeled in future research, not alveolar concentration. Finally, this study provides an example of using computer simulation to explore situations that are difficult to investigate clinically.

Conservative management of subglottic stenosis in pregnancy resulting in vaginal birth

We present a case of subglottic stenosis complicating pregnancy. The patient was born prematurely at 24 weeks gestation and required a twelve-month period of intubation. Airway trauma from prolonged intubation resulted in acquired subglottic stenosis. As an adult the patient had a longstanding audible stridor; however, was not breathless during activity before or during pregnancy. The patient went into spontaneous labour at 37+4 weeks and delivered vaginally with epidural analgesia. This case is significant, as no cases of a patient with such a degree of stenosis delivering vaginally without airway treatment have been reported.

Tuberculosis-induced tracheobronchial stenosis during pregnancy

Central airway stenosis is extremely rare in pregnancy and could lead to respiratory and cardiovascular embarrassment, especially at the time of delivery. Initially, patients may not show obvious signs of respiratory difficulty. Early recognition of the disease and anticipatory management of a complicated delivery are very important. We present a pregnant patient with tuberculosis-induced severe tracheobronchial stenosis and discuss the management challenges of her delivery.

Idiopathic subglottic stenosis in pregnancy: A deceptive laryngoscopic view

A 28-year-old lady with term gestation, pre-eclampsia and a vague history of occasional breathing difficulty, on irregular bronchodilator therapy, was scheduled for category 1 lower segment caesarean section in view of foetal distress. A Cormack-Lehane grade 1 direct laryngoscopic view was obtained following rapid sequence induction. However, it was not possible to insert a 7.0 or 6.0 size styleted cuffed tracheal tube in two attempts. Ventilation with a supraglottic device was inadequate. Airway was secured with a 4.0 size microlaryngeal surgery tube with difficulty. Computed tomography scan of the neck following tracheostomy for failed extubation revealed subglottic stenosis (SGS) with asymmetric arytenoid calcification. This report describes the management of a rare case of unrecognised idiopathic SGS in pregnancy.

Severe glottic stenosis in a parturient with ectodermal dysplasia

Airway stenosis in pregnancy is challenging and the literature does not offer consensus regarding its evaluation and anesthetic management. A 21-year-old nulliparous woman with ectodermal dysplasia and severe glottic stenosis was referred to the obstetric anesthesia team for evaluation and peripartum management recommendations. She had a history of a congenital complete glottic web that required a tracheostomy at birth. After decannulation at age four, she was lost to follow-up. On examination in early pregnancy, she was found to have a dangerously narrow airway with fixed vocal cords and a glottic aperture of 2-3mm. At nine weeks of gestation an elective tracheostomy was performed under local anesthesia. She later underwent an uneventful cesarean delivery under spinal anesthesia. Ultimately, early interdisciplinary planning for an elective tracheostomy helped assure patient safety during advancing pregnancy and delivery.

Jet ventilation for the excision of vocal cord polyps in a pregnant patient

The anaesthetic management of patients presenting with laryngeal tumours and airway obstruction is difficult. We present the case of a pregnant woman at 30 weeks gestation who underwent surgical removal of two vocal cord polyps under general anaesthesia using jet ventilation

Forehead is as sensitive as finger pulse oximetry during general anesthesia

PURPOSE

To compare the performance of a forehead probe to a conventional finger pulse oximetry probe in anesthetized patients.

METHODS

Eighteen patients participated in the study. Each probe was connected to a Nellcor N-550 pulse oximeter. Anesthesia was induced and maintained with propofol. After intubation, the patients received air to achieve a steady-state of peripheral arterial oxygen saturation (SpO(2)). Ventilation was interrupted to induce a hypoxic state. As soon as one of the two SpO(2)'s decreased to 90%, the patients' lungs were ventilated with 100% oxygen. To evaluate the performance of the two pulse oximeters, time to the lowest (TL), time of recovery (TR) and lag times to beginning of SpO(2) decrease (Lag) were measured.

RESULTS

There were no significant differences in TL and TR between forehead and finger pulse oximetry under normal perfusion conditions during general anesthesia. When the axillary artery was compressed to mimic reduced peripheral perfusion, SpO(2) in the forehead decreased sooner than in the finger during hypoxia. The forehead and finger TLs were similar, however, TR was significantly longer in the finger.

CONCLUSION

The forehead SpO(2) sensor can be used as an alternative to the conventional finger sensor during general anesthesia.