AccessAnesthesiology Blog

Symptomatic Arnold Chiari Malformation in a Gravid Female

mgelber — Wed, 13 Oct 2010 13:00:48 +0000

Authors: Dr. Christopher S. Manfred (Department of Anesthesiology, Dartmouth Hitchcock Medical Center) and Dr. Brian Sites (Department of Anesthesiology, Dartmouth Hitchcock Medical Center)

The patient was seen in the anesthesia pre-admission testing clinic for evaluation. On further questioning it was uncovered that the patient experienced symptoms including mild upper extremity paresthesias, occipital headaches, and dizziness, and syncopal events. She would become symptomatic with minor extensions of her neck, with supine positioning, during valsalva maneuvers (such as having bowel movements, coughing, or laughing), or with minimal exertion. Her pregnancy has been otherwise uncomplicated.
On review of systems, she has been troubled by persistent GERD throughout pregnancy that is being treated with antacids. The only other medicine she takes is a daily multi-vitamin. She has not had a previous anesthetic and denies family history of anesthetic complications or malignant hyperthermia.
On physical exam, the patient was a thin gravid female. Paresthesias and headaches were able to be elicited with minor neck extension and supine positioning. She had a Mallampati IV airway with less than 2 finger breadths mouth opening, prominent front incisors, 2 finger breadths thyromental distance, inability to extend her jaw, and was unable to extend her neck secondary due to Chiari symptoms. The rest of her physical exam was unremarkable.
After discussion with the patient regarding risks and benefits to the different methods of providing anesthesia for a c-section, the plan was formulated to attempt a single shot spinal block with the smallest diameter needle available. In the event a spinal block was unable to be performed, a general anesthetic with an awake fiber optic intubation was planned.
The night prior to the patient’s scheduled c-section, she presented in early spontaneous labor and was taken to the operating room for a c-section. The anesthesia team on at that time was able to successfully place a spinal bloc using a 25G pencil-point needle (after one unsuccessful attempt with a 27G pencil-point) containing 1.5ml of hyperbaric 0.75% bupivacaine with an epinephrine wash, 100 mcg of preservative free morphine sulfate, and 10 mcg of fentanyl. The patient experienced minor symptoms during delivery of the infant, but otherwise remained asymptomatic throughout the procedure.

Discussion

References

Morbidly Obese Patient with Cervical Spine Ankylosing Spondylitis Presenting with Acute Spinal Shock and Complex Airway Management

mgelber — Fri, 16 Jul 2010 17:48:52 +0000

Authors: Ulrike Berth MD, Shaheen Shaikh MD, Bronwyn Cooper MD, Stephen O. Heard, MD
Department of Anesthesiology, University of Massachusetts

Introduction

Preoperative Evaluation

Airway Management

Discussion

Ankylosing spondylitis leads to fibrosis, ossification, and ankylosis along the spinal column that can have a significant impact on airway management. Reduction in atlantooccipital articulation mobility, fixation of cervical vertebrae, and temporomandibular joint involvement can complicate airway management further. The cervical spine is also the most susceptible to fractures, particularly in hyperextension, that can lead to damage to the cervical spinal cord during intubation.This case illustrates the challenges posed by a morbidly obese patient in spinal shock with a stiff and unstable neck. The patient needed emergency surgery for traumatic paraplegia, but it was vital to stabilize the patient first. To ensure the most optimum outcome for this patient it was very important to have monitoring in place to be able to treat both anticipated and unforeseen events that might emerge during surgery. The entire anesthetic management of this patient was extremely formidable for many reasons. His morbid obesity caused challenging intravenous catheter placement, with additional concerns about securing the airway, high airway pressures and difficult ventilation intraoperatively in the prone position. Preoperative spinal shock, likely caused by shearing forces during the patient’s fall causing spinal cord injury well above the anatomical fracture site, resulted in hemodynamic instability. Type 2 diabetes mellitus and anticoagulation (warfarin therapy) were added concerns. The patient was stabilized in the PACU with a phenylephrine infusion, oxygen therapy, and fresh frozen plasma transfusions. Longstanding ankylosing spondylitis left the patient with a stiff neck with virtually no movement. Despite no acute fracture in his cervical spine, the cervical CT results showed osteophytes pressing against his spinal cord causing spinal cord compression. After considering all factors we felt the safest possible option to secure the airway was an awake fiberoptic intubation.Studies have shown that the Bullard laryngoscope, Glidescope, and Fastrack LMA can be safely used for the management of a difficult airway in patients with an unstable cervical spine. Further studies are needed to demonstrate their benefit versus the standard of awake fiberoptic intubation. Trauma patients often have unstable cervical spine injuries and the airway in the ED is often secured by rapid sequence intubation with manual inline stabilization. Our patient however not only had an unstable cervical spine but superimposed ankylosing spondylitis resulting in difficult airway management that was worsened by his morbid obesity.

References

Awake Fiberoptic Intubation Using Dexmedetomidine in a Compromised Airway Secondary to a Thyroid Carcinoma

mgelber — Tue, 15 Jun 2010 16:20:30 +0000

Rebecca A. Ruffle DO*, Shaheen Shaikh MD*, Daniel Kim, MD‡
*Department of Anesthesiology, ‡Department of Otolaryngology, University of Massachusetts, Worcester, MA, USA

Introduction

Preoperative Course

Airway Examination

Intraoperative Course

Postoperative Course

Discussion

This case illustrates the challenges of endotracheal intubation in a patient with a thyroid carcinoma. Airway management is a crucial element in the preoperative planning by the anesthesiologist. Failed intubation is associated with serious complications (5). This patient’s initial evaluation revealed normal mouth opening, a Mallampati score of 2, absence of a short neck, normal neck mobility and thyromental distance of two finger breaths. On physical exam this patient’s thyroid mass distorted the anatomy of the external structures of the neck. MRI showed both tracheal deviation and compression of the trachea.When a goiter is accompanied by airway deformity, the patient it at risk for difficult direct laryngoscopy and intubation (2). Studies have shown that it is not the large size of a goiter that is associated with a higher degree of difficulty intubating, rather, the presence of a cancerous goiter is a major risk factor in predicting difficult endotracheal intubation (1). Difficult intubation of the trachea in these patients is caused both by carcinoma and associated tissue invasion and fibrosis (1). Tissue invasion changes the physical anatomy of the structures and fibrosis may reduce mobility making direct laryngoscopic view difficult (1). Awake fiberoptic intubation remains the gold standard for anticipated difficult intubation in such patients (3). The role of sitting fiberoptic bronchoscopy has been discussed with great success in the setting of thyroid tumors (4). In this case we chose the sitting position to decrease compression and occlusion of the airway from structures of the oropharynx.Fiberoptic bronchoscopy and tracheal intubation is challenging in an awake patient. The patient was prepared with topical anesthesia to decrease airway sensation. Then the patient was given midazolam for anxiolysis and glycopyrolate for its antisialogogue properties. Dexmedetomidine was selected for both its anxiolytic and antisialogogue properties, but most importantly because it is asedative that causes minimal respiratory depression (7).Dexmedetomidine is a selective alpha-2 agonist. It produces sedation via activation of postsynaptic alpha-2 receptors in the locus coeruleus that regulate wakefulness (6). We found that dexmedetomidine provided a moderate level of sedation without causing respiratory distress or hemodynamic instability. The patient was sleepy but easily aroused. He was cooperative and easy to communicate with. The dexmedetomidine infusion allowed us to safely perform fiberoptic bronchoscopy and tracheal intubation on the first attempt.In conclusion, we found that dexmedetomine is a useful agent for sedation during awake, sitting, fiberoptic intubation of the difficult airway. It provided minimal respiratory impairment and adequate sedation and anxiolysis.

References

Angioedema Requiring an Awake Fiberoptic Nasotracheal Intubation Following Levofloxacin Administration in a Patient on Chronic Lisinopril and Aspirin Therapy

admin — Thu, 13 May 2010 20:13:35 +0000

Authors: Brian Martin, MD, and Shaheen Shaikh, MD

Department of Anesthesiology, University of Massachusetts Medical School, Worcester, MA

Introduction

Case Report

Figure 1: A photograph of the patient following successful fiberoptic nasotracheal intubation.

A 70-year-old woman with a history of hypertension, diabetes mellitus, previous angioedema and hypercholesterolemia, presented to the emergency department with complaints of tongue swelling awakening her from sleep. Her usual medications included lisinopril and aspirin. The patient had been discharged from the hospital four days earlier following treatment for a urinary tract infection. Following discharge, she was to take a five-day course of levofloxacin that had also been administered during her two-day hospital stay. She was transported to the hospital by ambulance and had received epinephrine subcutaneously and diphenhydramine intravenously. In the emergency department she was given additional doses of epinephrine subcutaneously and methylprednisolone intravenously. She was brought immediately to the operating room due to increasing tongue edema. In the operating room a surgical team was present for a possible emergency tracheostomy. The patient was given glycopyrrolate 0.3 mg and midazolam 1mg IV as premedication. Additional sedation was achieved with ketamine 30 mg. The patient remained sitting upright for the intubation. Oxymetazoline nasal spray was administered to the nares. A 7.5 mm endotracheal tube was lubricated with viscous lidocaine. The tube was placed in the left naris, advanced to the oropharynx, and then a fiberoptic bronchoscope was inserted through the endotracheal tube. The vocal cords were easily visualized and glottic edema was absent. The fiberoptic bronchoscope was then easily passed into the trachea and the endotracheal tube was advanced over the bronchoscope into the trachea. Proper endotracheal tube placement was confirmed via the presence of end tidal carbon dioxide and a second direct visualization of the carina (Figure 1). General anesthesia was induced with sevoflurane and propofol after securing the nasotracheal tube. The patient was transferred to the intensive care unit. The patient was extubated on hospital day 2 and was continued on intravenous steroids

Discussion

References

Case Discussion

Hypothyroidism in a Patient Presenting with Torsion of an Ovarian Cyst and a Possible Difficult Airway

admin — Sun, 21 Mar 2010 20:59:01 +0000

Authors: Andrew Cocchiarella, MD, Shaheen Shaikh, MD, William Frost, DO, and Stephen O. Heard, MD

Department of Anesthesiology, University of Massachusetts Medical School, Worcester, MA

Introduction

Preoperative evaluation

The patient’s longstanding hypothyroidism was secondary to familial pseudohypoparathyroidism that was also present in her mother, grandmother and maternal uncle. She was diagnosed with these endocrine disorders at age 8 and, due to noncompliance on the part of her family, was never effectively treated or followed. Her past medical history was also significant for developmental delay and morbid obesity (height 60”, weight 117 kg, BMI 50). She reportedly snored, but did not have apneic episodes while sleeping. Of note, she was actively vomiting while being evaluated by the anesthesia team.The patient was not cooperative with the physical examination and was unable to lie flat due to dyspnea. She was tachycardia (118/min) and hypotensive (77/36). Her respiratory rate was 18 and her oxygen saturation was 98% on room air. Her airway examination revealed a large tongue, Mallampati Class III airway, and reduced thyromental distance and neck extension. She had very poor dentition, including multiple missing teeth. A large abdominal mass extended above the umbilicus. She had no obvious peripheral veins and her only intravenous access was via a 22 gauge peripheral IV.Preoperative laboratory studies revealed hyponatremia (132mEql/L), hyperkalemia (5.5mEql/L), hypocalcemia (ionized calcium 3.0 mg/dL) and hypothyroidism (TSH 15.1 mIU/L). The bicarbonate concentration was 21mmol/L and the anion gap was 12. The hematocrit was 44%. A CT scan of the abdomen revealed a massive intraabdominal cyst.

Given the combination of a full stomach and a possibly difficult airway, we considered performing an awake fiberoptic intubation. Her developmental delay and uncooperative demeanor, however, precluded this option. We decided to proceed with an inhalational induction with maintenance of spontaneous ventilation.

The patient was given a bolus of crystalloid in the holding area and her hemodynamics improved. She was also given glycopyrrolate 0.2 mg IV, metoclopramide 10 mg IV, famotidine 20 mg IV and midazolam 2 mg IV and was brought to the operating room.

Intraoperative course

The patient was positioned in a semi-upright position and standard ASA monitors were placed. Induction was first attempted by placing a mask with 8% sevoflurane in oxygen over her face, but she was combative and would not allow a tight seal. She was then given ketamine 110 mg IV in divided doses that enabled her to tolerate the mask. Cricoid pressure was maintained throughout the induction. A slow, smooth induction with maintenance of spontaneous respiration was accomplished, though she did become hypotensive requiring several bolus doses of phenylephrine. After insertion of a second peripheral IV (20-gauge), direct laryngoscopy was performed with a Macintosh 4 blade that revealed a grade II view. A 7.0 mm endotracheal tube was inserted atraumatically on the first attempt and its proper location was confirmed with auscultation and capnography. Rocuronium 50 mg IV was then given and cricoid pressure was released. Anesthesia was subsequently maintained with isoflurane 0.8 ET% in oxygen and air, supplemented by periodic bolus doses of fentanyl.Intraoperatively the patient was fluid resuscitated with 1500 ml of crystalloid during the first hour. Though her urine output was adequate (~2 mL/kg/hr), she required a phenylephrine infusion to maintain her systolic blood pressure above 100 mm Hg. The combination of untreated hypothyroidism, hyponatremia, hyperkalemia, hypotension and the stress of the surgery prompted us to consider an Addisonian crisis. Thus hydrocortisone 100 mg IV was given approximately one hour into the case. At the same time, an infusion of levothyroxine 200 mcg was given due to the concern about precipitating myxedema coma. During the second half of the three-hour case, the patient was weaned off the phenylephrine infusion. Oxygenation and ventilation were adequate throughout the case.

Figure 1: The 35 x 40 cm, 11 kg ovarian mass after its removal.

The surgical findings included torsion of the left ovary which contained a 35 x 40 cm, 11kg cystic mass (Figure 1). A left salpingo-oophorectomy was performed, along with an appendectomy, partial omentectomy and right oophoropexy.

We had several concerns that prompted our decision to leave the patient intubated postoperatively, including the possibility of a prolonged recovery from anesthesia as well as the likelihood of high postoperative opioid requirements in the setting of altered respiratory responses to hypercapnia and hypoxia due to hypothyroidism.

Postoperative course

Discussion

Familial pseudohypoparathyroidism is a rare form of hypoparathyroidism that is due to resistance of peripheral tissues to the effects of parathormone. It is associated with a phenotype characterized by short stature, obesity, developmental delay, round face, dental hypoplasia and short metacarpals and metatarsals. The primary anesthetic concern in hypoparathyroidism is hypocalcemia, which can be profound. Most patients with pseudohypoparathyroidism Type 1A (the subtype implicated in this case) also have primary hypothyroidism.

The ideal preoperative management of hypothyroidism consists of restoration of normal thyroid status. Patients receiving T3 should take their usual dose on the day of surgery due to its relatively short half-life of 1.5 days. T4, however, has a long half-life of 7 days and its administration on the morning of surgery can be considered optional.

The anesthetic implications of hypothyroidism depend on the severity of the condition. Patients with markedly decreased serum T3 and T4 levels, those who manifest any severe clinical symptoms of chronic hypothyroidism, or those with myxedema coma are all at increased risk of having complications during the perioperative period. In general, untreated hypothyroidism decreases anesthetic requirements slightly. Patients may be profoundly sensitive to opioids that may be associated with prolonged recovery from anesthesia or may precipitate hypothyroid coma. Volatile agents should be used cautiously as even low concentrations may produce profound hypotension and exacerbate hypothermia. Incipient or overt hypothyroid coma is an indication for urgent perioperative thyroid hormone replacement, usually 200-400 mcg of intravenous levothyroxine (T4) followed by 100 mcg daily or 10-25 mcg of intravenous triiodothyronine (T3) every 8 hrs. Hypothyroid patients also have an increased incidence of adrenocortical insufficiency and may not mount an appropriate adrenocorticotropic hormone response to stress. Thus, stress-dose steroid coverage may be required during the perioperative period. Finally, the need for prolonged ventilatory support must be anticipated as recovery from anesthesia may be substantially delayed in hypothyroid patients.

This case was challenging because of its emergent nature, the unclear severity of the patient’s longstanding hypothyroidism, and the possibility of a difficult airway in an uncooperative patient with known developmental delay. An awareness of the anesthetic implications of untreated hypothyroidism may assist in providing a good outcome in cases like this.

References

Case Discussion

Have you ever dealt with a similar case? How did you/do you handle it?
How have you/would you have handled this case?