Emergency anesthetic management of an achondroplastic elderly gravida with polytrauma.

A 42-year-old pregnant female, diagnosed with achondroplasia, presented to our trauma center with multiple injuries after being involved in a motor vehicle accident. During her hospitalization, she underwent multiple surgeries and required admission in the intensive care unit. We describe the emergency anesthetic management of this patient, highlighting the effects of skeletal dysplasia on airway, cardiorespiratory system, and ventilatory mechanics. These effects, when superimposed upon with physiological changes of pregnancy, can lead to an unanticipated ventilatory challenge as we describe in this report. Copyright:

INTRODUCTION

Achondroplasia is the most common skeletal dysplasia causing dwarfism in humans with its incidence between 1 in 10,000 and 1 in 30,000 live births. It is characterized by disproportionate skeletal growth due to abnormal cartilage and bone development resulting in characteristic features such as short limbs (rhizomelia), midface hypoplasia, thoracolumbar kyphosis, and spinal stenosis.[1] Apart from dysplastic features, these patients tend to be obese with symptoms of obstructive sleep apnea and central apnea adding to the cardiorespiratory morbidity.[2] These factors combined together, predispose these patients to increased perioperative morbidity and mortality compared to the general population and therefore mandates a thorough preoperative evaluation which includes radiological imaging of the spine, pulmonary function testing, polysomnography, anticipating difficult airway, and arrangement of appropriate intensive care unit (ICU) facilities as backup.

Although uncommon, achondroplastics can present to the hospital requiring emergency surgery, where the conduct of the above investigations may not be possible. In this report, we describe a rare presentation of a 42-year-old achondroplastic elderly gravida who presented to our trauma center with polytrauma. Her anesthetic management offered a better understanding of respiratory pathophysiology in these patients. This will be described in this case report and the relevant anesthetic considerations in patients with achondroplasia.

CASE REPORT

An apparently well 42-year-old achondroplastic gravida with 26 weeks of gestation was involved in a motor vehicle accident. On presentation, she was conscious, oriented, and hemodynamically stable. She was breathing spontaneously with no apparent difficulties and maintaining oxygen saturation at 97% on room air. On auscultation, breath sounds were clear and equal on both sides. On the secondary survey, she was found to have sustained open Grade II fracture left distal shaft femur, fracture bilateral proximal tibia with degloving injury of the left thigh [Figure 1]. A focused assessment with sonography for free fluid abdomen was negative. Primary ultrasonography scan for fetal well-being showed fetal movements to be present. An urgent obstetrics consultation was done, and it was decided to follow fetal well-being with hourly ultrasound scan. However, a repeat scan done 4 h later showed absent fetal cardiac activity.

Figure 1

Bilateral leg radiograph showing right fracture distal femur with bilateral fracture proximal tibia

In view of the skeletal injuries with an intrauterine demise, the patient was planned for urgent long bone fixation surgery. Preanesthetic evaluation revealed her weight to be 57 kg, height of 124 cm, and body mass index of 37 kg/m2. She reported her exercise tolerance to be good with no past medical history, known allergies, or concurrent medication use. She did not give any history suggestive of obstructive sleep apnea. General examination revealed a large forehead, flat nose, and short neck. Airway examination revealed protruding incisors with mouth opening to three finger breadth leading to the visualization of hard palate only. Neck movements were normal. Routine blood investigations and preoperative arterial blood gas were normal. Chest radiograph taken bedside showed flattened ribs with cardiomegaly [Figure 2].

Figure 2

Chest radiograph showing flattened ribs with cardiomegaly

The patient was planned for rapid sequence induction with general anesthesia (GA). A difficult airway cart was prepared, and an arterial cannula was secured before induction. After preoxygenation for 3 min, GA was induced, and intubation attempted with endotracheal tube of size 6.5 mm internal diameter was successful at the first attempt. Bilateral equal air entry was confirmed. Immediately after intubation, the patient's oxygen saturation dropped, reaching a nadir of 78% with fraction inhaled oxygen (FiO2) of 1. Peak airway and plateau pressures were raised. Attempts for lung recruitment were made with manual bag ventilation. The patient's oxygen saturation gradually improved and settled at around 94% with FiO2 of 0.6 and positive end-expiratory pressure (PEEP) of 12 cm water. Anesthesia was maintained with isoflurane with mixture of oxygen and medical air. She underwent external fixation for fracture femur, while a decision was made to postpone the fixation surgeries for bilateral proximal tibia. Due to the patient's lung condition, it was decided to electively ventilate her and was shifted to the ICU. Her oxygenation status gradually improved overnight requiring minimal pressure support and PEEP. The patient was weaned off the ventilator and extubated the next day.

Follow-up

Over the course of her hospitalization, she underwent multiple surgeries which included open reduction and plating for bilateral tibia, hysterotomy for removal of dead fetus, and debridement and skin grafting for degloving injury under GA and were uneventful. She recovered well and was discharged to home care 8 weeks after her admission.

DISCUSSION

Although not as striking as long bones, the chest wall involvement in achondroplasia leads to a narrowed chest (reduced anteroposterior diameter and abnormal thoracic spine curvature). Spirometric studies investigating the effects of abnormal chest wall further demonstrated these patients to be having reduced vital capacity compared to normal individuals with similar age and adjusted height.[34] In addition, when pregnant, the large intraabdominal gravid uterus causes excessive diaphragmatic splinting resulting in greater than normal reduction in functional residual capacity in these patients.[5] We assume the physiological changes of pregnancy superimposed on preexisting reduced lung capacity led to sudden atelectasis upon induction in our patient resulting in rapid oxygen desaturation.

The other important anesthetic concerns in adult achondroplastics include spinal stenosis and neurogenic claudication, seen more commonly in those with persistent kyphosis. It usually starts to appear after the third and fourth decades of life, with about 80% of patients exhibiting some neurological signs of claudication and increased deep tendon reflexes in the sixth decade. Moreover, there have been case reports of failed spinal anesthesia and unpredictable spread of drugs in patients with skeletal dysplasia where epidural anesthetic was used.[56] The consensus among anesthesiologists thus remains to avoid neuraxial anesthesia in patients with skeletal dysplasias.[7] At the same time, successful use of neuraxial anesthesia for surgery in patients with achondroplasia has also been reported.[89] Although our patient did not elicit any signs or symptoms of neurological claudication, we considered it best to avoid neuraxial anesthesia in our patient.

Although rare, achondroplastics may present for emergency surgery which should alert an anesthesiologist to anticipate and avoid potential catastrophes related to airway and respiratory system in these patients. We also recommend these patients to be managed in a tertiary center with appropriate intensive care facilities.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting, and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to not require Institutional Review Board/Ethics Committee review, and the corresponding protocol/approval number is “not applicable.”

Declaration of patient consent

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

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Conflicts of interest

There are no conflicts of interest.