Consider the Use of Lidocaine in the Cuff of the Endotracheal Tube, But Be Aware of the Risks and Alternatives

Consider the Use of Lidocaine in the Cuff of the Endotracheal Tube, But Be Aware of the Risks and Alternatives

Jamey E. Eklund MD

Paul M. Kempen MD, PhD

Anesthesia providers must mitigate the undesired hemodynamic and neuromuscular responses to intubation. Usually (but of course, not always!), large doses of induction drugs and neuromuscular blockade smooth the way during intubation. Intraoperatively, an adequate level of inhalational anesthetic plus opioids will help the patient tolerate the endotracheal tube (ETT). On extubation, however, the dissipating anesthetic effects and re-emerging pharyngotracheal reflexes may lead to coughing and adverse symptoms, including tachyarrhythmias and increased intracranial, intraocular, or intravascular pressures, via the airway-circulatory reflex.

The incidence of coughing at extubation varies between 6.6% and 96%. Mitigating circulatory-airway reflex symptoms is especially important in patients with cardiovascular and reactive airway disease, neurosurgery, and certain head, neck, or ophthalmologic conditions. Multiple anesthetic strategies to prevent ETT-stimulated coughing have been described, including:

  • Elimination of the ETT completely during general anesthesia (i.e., mask anesthetics) or extubation during profound anesthesia when the ETT is no longer necessary (known universally as a “deep extubation”)

  • Use of local anesthetic via systemic intravenous (IV) or topical endotracheal administration

Anesthesia providers must consider patient history, co-morbidities, and surgical needs to select appropriate strategies.


Nonionized lidocaine has been shown to diffuse readily along a concentration gradient through the lipophilic plastic of an ETT cuff sufficiently to anesthetize adjacent mucosa, typically sparing the vocal cords (which are not in contact with the cuff). The cuff serves as a reservoir of local anesthetic. Comparing equal volumes of intracuff saline versus lidocaine, the incidence of postextubation coughing has been shown to be 59% versus 38%, respectively. Saline-filled cuffs functioned as the control and were shown to have comparable efficacy to air-filled cuffs. Estebe et al. extensively studied various concentrations of lidocaine (2% to 10%), as well as alkalinization of the lidocaine solution. Higher lidocaine concentrations and alkaline solution
pH effectively increase the available nonionized, lipophilic, and diffusible lidocaine. Alkalinization increases the available nonionized and diffusible lidocaine at any given concentration.


Although the use of lidocaine in the ETT cuff is appealing, serious potential risks deserve consideration. Plain or alkalinized lidocaine solutions (2% to 4%) are clinically effective while limiting exposure to potentially toxic (gram) amounts of intratracheal lidocaine from 10% solutions, should the approximately 10-mL-volume cuff rupture. Filling and deflating the cuff with noncompressible aqueous solutions typically occur much more slowly than with air, whereas similarly, complete elimination of intracuff air and the pressure-volume effects from N2O can be difficult. Many studies of intracuff lidocaine employed direct manometry to avoid excessive pressure; others inflated cuffs until positive-pressure ventilation at 20 cm H2O was confirmed without air leak. Prolonged cuff pressure >20 cm H2O can tamponade mucosal perfusion and result in tissue necrosis. Fluid-filled intracuff pressures may be difficult to assess, with slow fluid flow between pilot and tracheal balloons. Anesthesia providers who are unfamiliar with or unaware of fluid-filled cuffs may not completely empty them at extubation during the 1- to 2-second deflation attempt that is typical for air. Thus, the noncompressible fluid-filled ETT balloon may lead to vocal cord trauma when it is inadvertently pulled through the glottic opening. Although extubation with air-filled balloons was not found to cause arytenoid subluxation in several cadavers, the effect of fluid-filled balloons is unknown.

Albeit rare, cuff rupture has been reported, and lidocaine can be rapidly absorbed through the lung. Although diffusion from 10% lidocaine via intact ETT cuffs did not reach toxic plasma levels, systemic toxicity could occur if the cuff ruptures and releases >1 gram of lidocaine into circulation. Cuffs with pinhole-sized defects filled at minimal pressure typically leak slowly, thus limiting peak and rapid uptake and potential lidocaine toxicity. Knight et al. studied high-dose administration of lidocaine in a patient population to assess systemic toxicity. After induction with 6 mg/kg of lidocaine and maintenance anesthesia of 0.6 mg/kg diazepam and 50% N2O, a total of 21 mg/kg lidocaine via controlled intravenous infusion was administered up to the point of cardiac bypass without toxicity. Peak plasma concentrations of 9.5 mcg/mL were noted at sternotomy. Indeed, rapid parenteral injections carry a higher risk of toxicity; but based on this study, systemic toxicity should not be clinically evident in adults with doses smaller than 100 mg intravenous push or 160 mg via tracheal instillation.

Time-dependent diffusion of lidocaine from the cuff effectively limits toxicity, as hepatic metabolism occurs with a T1/2 of 90 minutes. With excessive pressure and resulting tracheal mucosa ischemia, systemic absorption may be further curtailed. In vitro studies demonstrated that higher
concentrations of lidocaine (4% vs. 2%), prolonged duration for diffusion (360 minutes vs. 60 minutes), and “priming” cuff membranes (by prefilling them) resulted in a maximum diffusion of only 17.49 mcg lidocaine. A similar independent study noted as much as 1% of a 4% lidocaine solution diffusing after 6 hours, whereas alkalinized lidocaine resulted in 65% diffusion of the stock solution (2 mL of 2% lidocaine) after 6 hours. Sufficient time must elapse for an effective topical accumulation of mucosal lidocaine, making intracuff lidocaine questionably effective in surgeries lasting <1 hour. Typically, cuffs are also prefilled significantly in advance to saturate the cuff membrane and to eliminate air, which may limit clinical utility in high-volume and rapid-turnover practices. Two separate in vivo studies comparing control to lidocaine-filled cuffs showed very significant cough suppression (5% vs. 70% and 16% vs. 38% to 44%, respectively). The primary goal of intracuff lidocaine is to prevent adverse hemodynamic and oxygenation changes. Unfortunately, this occurred with limited success: “The emergent hemodynamic and oxygenation saturation data were similar for all three groups [air, saline, lidocaine]”—Fagan et al.


The minimal anesthetic concentration for suppression of the airway-circulatory reflex from the ETT at extubation (MAC extubation on MACex) is comparable to the stimulus of skin incision and is effectively managed at 1.2 MAC. Extubation at MACex can effectively mitigate hemodynamic and hyperreactive airway responses from tracheal stimulation once the ETT is no longer required. “Deep extubation” involves removing the ETT while the patient is in a surgical plane of anesthesia. Removing the endotracheal tube can subsequently reduce anesthetic depth requirements, as surgical stimulation abates and dressings are applied, and can thus expedite emergence and transfer to the postoperative acute care unit. The anesthesia provider must, however, demonstrate airway skills to ensure adequate ventilation throughout emergence. Deep extubation is best performed after spontaneous respiration becomes evident. Removing an unnecessary ETT results in a situation equivalent to anesthesia via mask ventilation and with similar contraindications (i.e., high aspiration risk, difficult airway/high ventilation pressure requirements). Daley et al. showed that most anesthesia providers are hesitant to extubate in a deep plane of anesthesia because of aspiration risk. Thus, placement of a Salem sump (naso-gastric tube) after intubation (with removal immediately before extubation) maximizes stomach decompression and helps identify particulate stomach content.

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Jul 1, 2016 | Posted by in ANESTHESIA | Comments Off on Consider the Use of Lidocaine in the Cuff of the Endotracheal Tube, But Be Aware of the Risks and Alternatives

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