Abstract
Background
Tracheostomy is increasingly performed as a planned procedure for a wide range of indications. While superficial cervical plexus block (SCPB) is widely used as regional anesthesia for tracheostomy, its limitation in suppressing laryngeal reflexes may lead to discomfort and complications. Combining bilateral SCPB with bilateral superior laryngeal nerve block (SLNB) could potentially improve patient outcomes by reducing airway reflexes.
Objective
This study aimed to compare the effectiveness of bilateral SCPB alone versus bilateral SCPB combined with bilateral SLNB in sedated patients undergoing surgical tracheostomy.
Methods
A double-blind, randomized controlled trial was conducted at Alexandria University Hospital. A total of 120 adult patients, both intubated and non-intubated, requiring elective tracheostomy was randomly allocated into two groups: Group 1 received an ultrasound-guided bilateral SCPB alone, while Group 2 received a combination of ultrasound-guided bilateral SCPB and bilateral SLNB. The primary outcome was the incidence of intraoperative coughing and laryngospasm. Secondary outcomes included postoperative pain, cumulative analgesic requirements, time to first analgesic request, postoperative complications and patients’ satisfaction.
Results
Group 2 (SCPB + SLNB) demonstrated a significantly lower occurrence of coughing and laryngospasm compared to Group 1 (p < 0.05). No significant difference was observed in postoperative pain intensity between the two groups. Additionally, postoperative complications and patients’ satisfaction were comparable between both groups, with no significant differences noted.
Conclusion
The addition of bilateral SLNB to SCPB significantly suppresses airway-related reflexes during tracheostomy.
Highlights
- •
Reduced airway reflexes with combined SCPB and SLN block.
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Addition of SLN block had no significant effect on postoperative pain control.
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No increase in postoperative complications when combining SCPB and SLN block.
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Ultrasound guidance enabled precise nerve localization of SCPB and SLN block administration.
1
Introduction
Tracheostomy is a surgical procedure creating an opening in the trachea to secure the airway, indicated for patients needing prolonged mechanical ventilation, those with laryngeal disorders, or individuals unable to undergo intubation due to conditions like laryngeal paralysis, tumors, edema, or trauma [ , ]. It reduces ICU stays, enhances comfort, and minimizes aspiration risk [ ]. While prolonged ventilation is the primary indication, it is also performed emergently to ensure airway safety [ , ] (see Figs. 1–3 ).
Various anesthetic approaches for tracheostomy include general, regional, and local anesthesia. Regional anesthesia is preferred when general anesthesia is unnecessary or poses systemic risks. The superficial cervical plexus block (SCPB) provides effective analgesia with fewer complications than deep blocks, though risks include hematoma, local anesthetic systemic toxicity (LAST), vascular or neural injury, and unintended phrenic nerve blockade causing respiratory impairment [ ].
SCPB is widely used in carotid endarterectomy, thyroid procedures, and vocal cord interventions [ ]. Ultrasound guidance improves precision and safety by visualizing muscles, cervical vertebrae, vessels, nerves, and fascia [ ]. The cervical plexus (CP), formed by spinal nerves C1–C4, gives rise to the greater auricular, transverse cervical, lesser occipital, and supraclavicular nerves, providing sensory innervation to the anterolateral neck, shoulder, and ear [ ]. However, SCPB may not fully inhibit laryngeal reflexes, risking discomfort, coughing, or laryngospasm during tracheostomy cannula insertion [ ].
Combining SCPB with a superior laryngeal nerve block (SLNB) can address this limitation. The SLN, a vagus nerve branch, divides into external (controlling cricothyroid muscle) and internal branches (sensory innervation to mucosa above vocal cords). The internal branch triggers cough and laryngeal adductor reflexes, making SLNB valuable for suppressing airway reflexes during tracheostomy [ ]. Ultrasound-guided SLNB enhances precision and safety, reducing risks like vascular injury, nerve trauma, or anesthetic spread to the recurrent laryngeal nerve (RLN) [ ].
The airway is innervated by autonomic and sensory nerves, primarily the vagus nerve, which provides parasympathetic fibers to the trachea, bronchi, and larynx, regulating bronchoconstriction, mucus secretion, and reflexes. The RLN, a vagus branch, controls intrinsic laryngeal muscles (except cricothyroid) and supplies sensory innervation below the vocal cords, playing a vital role in airway protection [ ]. The glossopharyngeal nerve (cranial nerve IX) contributes to sensory innervation of the pharynx and posterior tongue, crucial for swallowing and gagging reflexes [ ].
This trial primarily aimed to assess the effectiveness of bilateral SCPB alone versus its combination with bilateral SLNB for tracheostomy in sedated patients. Our objective was to evaluate whether adding SLNB could reduce airway irritation, suppress laryngeal reflexes, and minimize coughing and laryngospasm, ultimately improving patient comfort and safety during the procedure.
2
Methods
2.1
Study design
This randomized, parallel-group, double-blind controlled trial was conducted at the Ear, Nose and Throat (ENT) department of Alexandria University Hospital over one year. Patients, surgeons, and outcome assessors were blinded to group assignment. Ethical approval was obtained from the Alexandria University Research Ethics Committee (IRB No: 00012098), and the trial was registered in the Pan African Clinical Trial Registry (PACTR 202407555927073). Informed consent was obtained from all participants, and the study adhered to CONSORT guidelines and the Helsinki Declaration.
A total of 120 intubated and non-intubated patients were enrolled and randomized using a computer-generated list (1:1 allocation ratio) with sealed, opaque envelopes to maintain blinding. Inclusion criteria were age 18–75 years, indication for elective surgical tracheostomy, ASA classification I-III, and ability to provide informed consent. Exclusion criteria included cognitive impairment, chronic opioid use, contraindications to regional anesthesia (e.g., coagulopathy, infection at the injection site), local anesthetic allergy, pregnancy, or inability to consent. Intubated ICU patients were included only if awake, alert, and communicative. Cases with unsuccessful blocks were excluded.
2.2
Study interventions
Following randomization, 120 sealed envelopes labeled 1 to 120 were prepared. Group 1 received bilateral SCPB with 10 mL of 0.5 % bupivacaine per side (total 20 mL) and a placebo (2 mL normal saline per side, total 4 mL) to mimic SLNB. Group 2 received bilateral SCPB with 10 mL of 0.5 % bupivacaine per side (total 20 mL) and bilateral SLNB with 2 mL of 2 % lidocaine per side (total 4 mL). After enrollment, two research assistants, who had no further role in the study, assembled 20 mL and 4 mL syringes in accordance with the specifications outlined in the envelopes. Each syringe was labeled with the patient’s assigned randomization number. All remaining investigators, staff, and patients remained unaware of group allocations.
Patients were transferred to a block room, monitored, and positioned supine. Skin was disinfected with 2 % chlorhexidine in 70 % isopropyl alcohol. Blocks were performed by a trained anesthesiologist using a 6–13 MHz linear ultrasound probe (Sonosite) with a sterile sheath, in-plane technique, and a 22-gauge, 50 mm needle (Stimuplex Ultra 360, Braun, Germany). Patients fasted for ≥6 h pre-procedure. After transferring patients to the operating room, each patient received lactated Ringer’s infusion, and 0.05 mg/kg iv midazolam. For patients who were intubated and admitted to the ICU prior to tracheostomy, standard ICU protocols were followed, including continuous monitoring of vital signs. These patients were closely managed by the ICU team to ensure stability during tracheostomy. After the tracheostomy, patients were transferred back to the ICU for continued observation and care. Administration of sedatives and analgesics was adjusted based on each patient’s response.
2.2.1
Bilateral SCPB
The head was rotated opposite the side, and the transducer placed horizontally at the sternocleidomastoid midpoint. After 1 mL of 2 % lidocaine for skin anesthesia, 10 mL of 0.5 % bupivacaine was injected beneath the sternocleidomastoid-trapezius fascia above the interscalene groove per side, with spread visualized under ultrasound [ ].
2.2.2
Bilateral SLNB
The neck was slightly extended, and the hyoid bone’s greater horn identified. Two mL of 2 % lidocaine was injected around it per side [ ]. SLNB was performed 5 min post-SCPB, followed by ≥ 15 min of monitoring. SCPB success was confirmed by reduced cold sensation over the neck within 15 min; SLNB success was confirmed by ultrasound visualization of anesthetic spread.
2.2.3
Tracheostomy procedure
Tracheostomies were performed in the operating room using standard surgical methods (horizontal slit, vertical slit, or window procedure) [ ]. Throughout the procedure, patients received 100 % oxygen via facemask and 50 mcg iv fentanyl for discomfort. No local anesthetic was administered at the incision site. Persistent discomfort was managed with 0.5 mg/kg iv ketamine boluses. Post-procedure, patients were transferred to the Post-Anesthesia Care Unit.
2.3
Outcomes
2.3.1
Primary outcome
The incidence of coughing and laryngospasm during tracheostomy, assessed in real-time by trained healthcare providers, was recorded as binary outcomes (present/absent) and severity (mild, moderate, severe) at predefined time points: start of tracheostomy, tube insertion, and emergence. Coughing was defined as forceful air expulsion through the tracheal tube [ ], graded as mild (minimal vocal cord movement), moderate (noticeable air expulsion), or severe (forceful expulsion with significant secretion movement) [ ]. Laryngospasm, defined as involuntary vocal cord closure causing airflow obstruction, was identified by stridor and increased respiratory effort [ ], graded as mild (partial closure, minimal impact), moderate (increased airway resistance requiring intervention), or severe (near/complete closure needing urgent treatment) [ ].
2.3.2
Secondary outcomes
Patients were requested to assess their pain intensity at rest using a Numeric Rating Scale (NRS) immediately after surgery, at 6 h, 12 h, and 24 h. Pain scores were from 0 (no pain) to 10 (worst possible pain). All patients received iv diclofenac sodium 75 mg every 12 h iv morphine 0.1 mg/kg for patients with an NRS equal to or above 4, with subsequent doses until the pain score decreased to three. Total iv ketamine (mg), the initial 24 h cumulative morphine (mg) and the times taken until the first request for additional analgesia were recorded. Postoperative complications such as bleeding, postoperative nausea and vomiting, wound infection, or tube displacement were recorded. patient satisfaction was conducted using a simple binary (“Yes” or “No”) format [ ].
2.3.3
Statistical methods
A sample size of 120 patients (60 per group) provided 80 % power to detect a 25 % difference in complications between isolated SCPB and SCPB + SLNB using Chi-square tests at a 0.05 significance level (IBM SPSS Statistics, ver. 29) [ ]. Data were analyzed using IBM SPSS 24.0. Qualitative data were described as numbers/percentages, with Chi-square tests for categorical variables. Quantitative data were summarized as mean ± standard deviation, with independent t-tests for normally distributed data. Significance tests were two-tailed (p < 0.05).
3
Results
Of 134 assessed patients, 14 were excluded (12 did not meet criteria, 2 declined), leaving 120 randomized (9 intubated in Group 1, 8 intubated in Group 2). Tracheostomy tube insertion was successful in all cases. Demographic and clinical characteristics (age, sex, BMI, ASA status) and pathological conditions (e.g., laryngeal, tongue, esophageal, lip cancer) were similar between groups ( Table 1 ).
| Group 1 (n = 60) | Group 2 (n = 60) | Statistical Analysis | ||
|---|---|---|---|---|
| Age (years) | t | p | ||
| Min. | 54 | 55 | ||
| Max. | 80 | 79 | ||
| Mean ± SD | 67.02 ± 6.93 | 66.85 ± 6.89 | 1.741 | 0.584 |
| Median | 66.0 | 66.5 | ||
| Sex | χ 2 | p | ||
| Male (no., %) | 48 (80.0 %) | 45 (75.0 %) | 0.414 | 0.122 |
| Female (no., %) | 12 (20.0 %) | 15 (25.0 %) | 0.763 | 0.177 |
| BMI (kg/m2) | t | p | ||
| Min. | 17.90 | 17.80 | ||
| Max. | 25.70 | 25.40 | ||
| Mean ± SD | 21.71 ± 1.83 | 21.69 ± 1.80 | 1.899 | 0.372 |
| Median | 21.80 | 22.05 | ||
| ASA Physical Status Classification | χ 2 | p | ||
| ASA I (no., %) | 7 (11.67 %) | 5 (8,3 %) | 0.665 | 0.148 |
| ASA II (no., %) | 46 (76.67 %) | 45 (75.0 %) | 0.606 | 0.392 |
| ASA III (no., %) | 7 (11.67 %) | 10 (16.67 %) | 0.622 | 0.349 |
| Pathological Condition | χ 2 | p | ||
| Cancer larynx | 36 (60.0 %) | 34 (56.7 %) | 0.235 | 0.171 |
| Cancer tongue | 11 (18.4 %) | 8 (13.3 %) | 0.870 | 0.130 |
| Esophageal cancer | 8 (13.3 %) | 12 (20.0 %) | 0.525 | 0.261 |
| Cancer lip | 5 (8.3 %) | 6 (10.0 %) | 0.611 | 0.791 |
Cough incidence was identical at surgery start (mild only, no significant difference). During tube insertion and emergence, Group 2 had significantly fewer cough cases than Group 1. Mild/moderate cough was more frequent in Group 1; severe cough was absent in both groups ( Table 2 ). No laryngospasm occurred at surgery start or emergence. During tube insertion, Group 2 had fewer laryngospasm cases than Group 1: mild (20.0 % Group 1, 11.7 % Group 2), moderate (6.7 % Group 1, 3.3 % Group 2), and severe (3.3 % Group 1, 0 % Group 2) ( Table 3 ).
| Incidence of Cough | Group 1 (n = 60) | Group 2 (n = 60) | χ 2 | p | ||
|---|---|---|---|---|---|---|
| Number | Percentage | Number | Percentage | |||
| Start of Surgery | ||||||
| Total incidence | 4 | 6.7 % | 4 | 6.7 % | 0.924 | 0.663 |
| Mild | 4 | 6.7 % | 4 | 6.7 % | 0.754 | 0.243 |
| Moderate | 0 | 0.0 % | 0 | 0.0 % | ||
| Severe | 0 | 0.0 % | 0 | 0.0 % | ||
| Tracheostomy Tube Insertion | ||||||
| Total incidence | 18 | 30.0 % | 9 | 15.0 % | 3.771 | <0.001∗ |
| Mild | 10 | 16.7 % | 7 | 11.7 % | 0.667 | 0.113 |
| Moderate | 6 | 10.0 % | 2 | 3.3 % | 0.467 | 0.315 |
| Severe | 2 | 3.3 % | 0 | 0.0 % | ||
| Emergence from Anesthesia | ||||||
| Total incidence | 9 | 15.0 % | 3 | 5.0 % | 5.013 | <0.001∗ |
| Mild | 7 | 11.7 % | 3 | 5.0 % | 0.744 | 0.691 |
| Moderate | 2 | 3.3 % | 0 | 0.0 % | ||
| Severe | 0 | 0.0 % | 0 | 0.0 % | ||
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