Role of Point of Care Ultrasound (POCUS) in Percutaneous Tracheostomy
Published on: February 22, 2022
Percutaneous tracheostomy (PcT) is a technique first described by Shelden in 1957. Over 100,000 adults in the United States receive tracheostomies each year. More than 50% of these are for prolonged mechanical ventilation due to acute respiratory failure.[1] Traditionally, tracheostomy is favored prior to the fourteenth day of mechanical ventilation to minimize injury to the tissue surrounding the endotracheal tube and to initiate aggressive ventilator weaning. Ultrasound-guided PcT (US-PcT) is advantageous with respect to cost, provides useful information about variations in the neck anatomy, identification of multiple bleeding structures (i.e. thyroid isthmus, anterior, jugular, and inferior thyroid vessels), and measures the distance from skin to the trachea, thereby allowing the choice of an appropriately sized tracheostomy tube.[2] When compared to surgical tracheostomy (ST) it involves lesser dissection and tissue trauma, and therefore fewer wound complications such as hemorrhage and infection.[3] The PcT is commonly performed in the neurocritical unit often secondary to impaired consciousness and/or insufficient protective reflexes. In an observational study of 118 patients in the neurocritical care unit comparing ST vs PcT, the procedural time was lengthier in the ST than PcT (39.0 [30.0–60.0] min vs. 15.0 [11.0–23.0] min, p<0.001). Also, procedure-induced complications were more common in patients who underwent ST compared to those who underwent PcT (26.3% vs. 11.5%, p=0.039).[4]
Clinical Course
A 58-year-old woman initially presented for an outpatient laparoscopic cholecystectomy for symptomatic cholelithiasis. Her perioperative course was complicated by left sided hemiplegia and global aphasia. A stroke alert was subsequently activated with CT head revealing a large 5.3cm x 5.2cm x 5cm hemorrhage with underlying edema and mass effect causing subfalcine herniation measuring about 9mm. Patient was taken for an emergent decompression with right frontal lobectomy. Intraoperatively, post tumor resection the patient had substantial worsening of her brain swelling. CT head revealed diffuse subarachnoid hemorrhage (Hunt & Hess scale 4, Modified Fischer scale 4) and early hydrocephalus (Fig.1). Upon re-exploration, a complex wide-neck anterior cerebral artery aneurysm measuring 4 mm was discovered. Subsequently, the patient underwent successful clipping of this aneurysm.
On arrival to the NeuroICU, the patient remained comatose. We initiated 3% hypertonic saline for mass effect reduction, nimodipine for vasospasm prevention, daily transcranial doppler (TCD) and Electroencephalogram (EEG) monitoring for any seizure activity and alpha-delta variability to detect any early vasospasm. Her course was further complicated by increased respiratory secretions and febrile episodes. Sputum cultures grew Citrobacter koseri. With the development of Ventilator-associated pneumonia and anticipated prolonged neurological recovery, early PcT for this patient was pursued. A Bedside ultrasound was performed prior to the procedure and the necessary landmarks were noted. A Sonosite PX (Fujifilm SonoSite Inc, Bothell, WA, USA) point-of-care ultrasound machine was used, with a 19 to 5 MHz linear array probe. The mode of imaging in our patient was set to maximal resolution and the depth adjusted to keep the trachea within the screen. We used axial imaging to identify the trachea and its surrounding structures (Figures 2,3&4). Our Patient had an uneventful procedure with minimal bleeding complication. Post tracheostomy, we were able to wean her sedation to assess neurological recovery and monitor treatment response effectively. She was initiated on ventilator weaning once her neurological status improved. Her ventilator was discontinued on day 13 post tracheostomy and placed on a tracheal mask.
Discussion
Patients in whom prolonged recovery is anticipated benefit from an early tracheal tube placement for the reasons described above. Although patients like the one above are not traditionally described in the literature as benefitting from early tracheostomy, in the NeuroICU this is a common practice. Spontaneous awakening assessments and regular neurological assessments necessitate minimal sedation which is best achieved with a tracheal tube.
There is no consensus on the optimal timing of tracheostomy in the ICU. The literature offers two categories of ‘early’ and ‘late’ for the timing of tracheostomy. However, these groups are not precisely defined resulting in overlap between the categories. A recent Cochrane Review of randomized controlled trials (RCTs) defined timing of tracheostomy as ‘early’ (10 days postintubation)[5]. Young et al in their study reported at any point between 4-14 days.[6] Similar to the timing of tracheostomy, evidence on the advantages of early over later tracheostomy also remains conflicting. A recent meta-analysis showed early tracheostomy was associated with shorter ICU length of mechanical ventilation. Although, no significant difference was observed between early and late tracheostomy for total hospital stay.[7] Additionally, Chorath et. al. reported early tracheostomy no more than 7 days after ventilator support may lower the rate of ventilator-associated pneumonia and ventilator duration.[8] In above-mentioned studies, bleeding has been the most common complication of tracheostomy. In many instances, bleeding complications have been minor (stomal venous bleeding).[9].
POCUS is a useful modality to identify landmarks prior to initiating the PcT, to determine if vasculature and/or the thyroid will be encountered during placement which may alter the surgical approach (Figure 4). With POCUS the depth of the trachea can be determined prior to needle placement (Figure 3). In a recent randomized study comparing the traditional landmark technique; ultrasonography-guided long-axis approach; and short-axis approach, it was found that POCUS guided tracheostomy had a lower number of punctures, a high first entry success rate, and fewer bleeding complications in comparison to the traditional landmark technique.[10] The French Intensive care society strongly agrees (Grade 2+) on the use of POCUS prior to the procedure.[11] In the given doppler images of our patient (Figure 4), we were able to identify the tracheal rings and noted the absence of blood vessels along the tract of dissection. This allowed for a bloodless dissection and reduced the risk of complications.
Another important consideration is the transient rise in intracranial pressure while performing bronchoscopy during PcT. Especially in acute brain injury patients undergoing early PcT, one may see the effects of hypoventilation and hypercarbia with prolonged bronchoscopy times. This is overcome with the help of ICP monitoring and allowing intervals of ventilation during procedure. Patients with hemodynamic instability, intracranial hypertension (ICP >15 mmHg), severe hypoxemia (PaO2/FiO2 <100 mmHg, with positive expiratory pressure > 10 cmH2O) and uncorrected bleeding disorders are at high risk of complications. PcTshould be avoided in patients with these complications. The relative contraindications to bedside PcT placement include variations in neck or tracheal anatomy, cervical injury, morbid obesity, and coagulopathy. The use of real time ultrasound guided tracheostomy has helped overcome some of these contraindications. Rajajee et al. used real time ultrasound guidance on morbidly obese, patients with cervical spine precautions, and previous tracheostomies for successful placement of tracheostomy tube. [12]
Conclusion
PcT is a safe bedside procedure with a low rate of complications. Early PcT can be considered in patients with anticipated prolonged mechanical ventilation and neuromuscular disorders. The use of POCUS is a promising tool that minimizes complications of bleeding and delineates anatomy prior to the procedure.
References
- Mehta, A.B., et al., Trends in Tracheostomy for Mechanically Ventilated Patients in the United States, 1993-2012. Am J Respir Crit Care Med, 2015. 192(4): p. 446-54.
- Muhammad, J.K., et al., Percutaneous dilatational tracheostomy: haemorrhagic complications and the vascular anatomy of the anterior neck. A review based on 497 cases. Int J Oral Maxillofac Surg, 2000. 29(3): p. 217-22.
- Durbin, C.G., Jr., Tracheostomy: why, when, and how? Respir Care, 2010. 55(8): p. 1056-68.
- Kwon, J., Y.O. Kim, and J.-A. Ryu, Safety and Feasibility of Percutaneous Dilatational Tracheostomy Performed by a Neurointensivist Compared with Conventional Surgical Tracheostomy in Neurosurgery Intensive Care Unit. J Neurointensive Care, 2019. 2(2): p. 64-69.
- Young, D., et al., Effect of early vs late tracheostomy placement on survival in patients receiving mechanical ventilation: the TracMan randomized trial. Jama, 2013. 309(20): p. 2121-9.
- Deng, H., et al., Early versus late tracheotomy in ICU patients: A meta-analysis of randomized controlled trials. Medicine, 2021. 100(3).
- Chorath, K., et al., Association of Early vs Late Tracheostomy Placement With Pneumonia and Ventilator Days in Critically Ill Patients: A Meta-analysis. JAMA Otolaryngol Head Neck Surg, 2021. 147(5): p. 450-459.
- Kupeli, I. and R.A. Nalbant, Comparison of 3 techniques in percutaneous tracheostomy: Traditional landmark technique; ultrasonography-guided long-axis approach; and short-axis approach – Randomised controlled study. Anaesthesia Critical Care & Pain Medicine, 2018. 37(6): p. 533-538.
- Trouillet, J.L., et al., Tracheotomy in the intensive care unit: guidelines from a French expert panel. Annals of Intensive Care, 2018. 8(1): p. 37.
- Rajajee, V., et al., Real-time ultrasound-guided percutaneous dilatational tracheostomy: a feasibility study. Crit Care, 2011. 15(1): p. R67.