Inhalation of volatile anesthetics via a laryngeal mask is associated with lower incidence of intraoperative awareness in non-critically ill patients

<div><p>Background</p><p>Increased incidence of intraoperative awareness was reported in critically ill patients during major operations, particularly under total intravenous (TIVA) or endotracheal general anesthesia (ETGA). However, the incidence and effect of anesthesia techniques on awareness in generally healthy, non-critically ill patients during operations have yet to receive significant attention.</p><p>Methods and results</p><p>This retrospective matched case-control study was conducted between January 2009 to December 2014. Surgical patients (ASA physical status I-III) whom reported intraoperative awareness during this study period were interviewed and their medical records were reviewed. The potential risk factors for awareness were compared with the non-case matched controls, who were randomly selected from the database. A total of 61436 patients were included and 16 definite cases of intraoperative awareness were identified. Patients who received ETGA and TIVA had significantly higher incidence of developing awareness compared to those who were anesthetized using laryngeal masks (LMA) (P = 0.03). Compared with the matched controls (n = 80), longer anesthesia time was associated with increased incidence of awareness (odds ratio 2.04; 95% CI 1.30–3.20, per hour increase). Perioperative use of muscle relaxant was also associated with increased incidence of awareness, while significantly lower incidence of awareness was found in patients who were anesthetized with volatile anesthetics.</p><p>Conclusions</p><p>The overall incidence of awareness was 0.023% in the ASA≤ III surgical patients who received general anesthesia. Anesthesia with a laryngeal mask under spontaneous ventilation and supplemented with volatile anesthetics may be the preferred anesthesia technique in generally healthy patients in order to provide a lower risk of intraoperative awareness.</p></div

Characteristics and descriptions of intraoperative awareness.

<p>Characteristics and descriptions of intraoperative awareness.</p

Study design and flow diagram.

<p>ASA PS: American Association of Anesthesiologists physical status; EA: epidural anesthesia; ICU: intensive care unit; NB: nerve block; SA: spinal anesthesia.</p

Conditional logistic regression analysis of the risk factors associated with awareness.

<p>Conditional logistic regression analysis of the risk factors associated with awareness.</p

Incidence and risk factors for postoperative lingual neuropraxia following airway instrumentation: A retrospective matched case-control study

<div><p>Background</p><p>Lingual nerve injury or neuropraxia is a rare but potentially serious perioperative complication following airway instrumentation during general anesthesia. This study explored the the incidence and perioperative risk factors for lingual nerve injury in patients receiving laryngeal mask (LMA) or endotracheal (ETGA) general anesthesia in a single center experience.</p><p>Methods and results</p><p>All surgical patients in our hospital who received LMA or ETGA from 2009 to 2013 were included, and potential perioperative risk factors were compared. Matched controls were randomly selected (in 1:5 ratio) from the same database in non-case patients. A total of 36 patients in the records had reported experiencing tongue numbness after anesthesia in this study. Compared with the non-case surgical population (n = 54314), patients with tongue numbness were significantly younger (52.2±19.5 vs 42.0±14.5; P = 0.002) and reported lower ASA physical statuses (2.3±0.7 vs 1.6±0.6; P<0.001). Patient gender, anesthesia technique used, and airway device type (LMA or ETGA) did not differ significantly across the two groups. A significantly higher proportion of patients underwent operations of the head-and-neck region (38.9 vs 15.6%; P = 0.002) developed tongue numbness after anesthesia. Multivariate logistic regression analysis indicated that head-and-neck operations remained the most significant independent risk factor for postoperative lingual nerve injury (AOR 7.63; 95% CI 2.03–28.70).</p><p>Conclusion</p><p>The overall incidence rate of postoperative lingual neuropraxy was 0.066% in patients receiving general anesthesia with airway device in place. Young and generally healthy patients receiving head-and-neck operation are at higher risk in developing postoperative lingual neuropraxy. Attention should be particularly exercised to reduce the pressure of endotracheal tube or laryngeal mask on the tongue during head-and-neck operation to avert the occurrence of postoperative lingual neuropraxy.</p></div

Characteristics of patients with postoperative lingual neuropraxy.

<p>Characteristics of patients with postoperative lingual neuropraxy.</p

Conditional logistic regression analysis of the risk factors associated with postoperative lingual neuropraxy (cases vs non-cases population, n = 36 vs 54314).

<p>Conditional logistic regression analysis of the risk factors associated with postoperative lingual neuropraxy (cases vs non-cases population, n = 36 vs 54314).</p

Characteristic analysis of postoperative lingual neuropraxy in cases and matched control patients.

<p>Characteristic analysis of postoperative lingual neuropraxy in cases and matched control patients.</p

Characteristic analysis of postoperative lingual neuropraxy (LN) in at-risk patients.

<p>Characteristic analysis of postoperative lingual neuropraxy (LN) in at-risk patients.</p

Conditional logistic regression analysis of the risk factors associated with postoperative lingual neuropraxy (cases vs matched controls, n = 36 vs 180).

<p>Conditional logistic regression analysis of the risk factors associated with postoperative lingual neuropraxy (cases vs matched controls, n = 36 vs 180).</p