Identification of independent predictors for intravenous thiopental-induced yawning

Yawning and airway physiology: a scoping review and novel hypothesis

Background and purpose

Yawning is a stereotypical complex muscular movement and is commonly executed by most vertebrates. In seconds, the entire airway is fully dilated and surrounding muscles are powerfully stretched, most prominently around the pharynx. To date, yawning has been rarely studied, and as of yet there is no consensus on its main function.

Material and methods

To investigate a mechanical airway function for yawning, a literature search was conducted to relate the frequency of yawning and obstructive airway conditions.

Results

The results show that changes in obstructive airway conditions and alteration of the frequency of yawning are temporally related.

Interpretation

These relationships, however, cannot be interpreted as causal, nor can they be extrapolated to explain the function of yawning. Yet airway management and yawning share many physiological characteristics. We therefore propose a novel hypotheses: yawning plays a significant role in airway physiology by muscle repositioning and widening the airway lumen, thereby securing long-term oxygenation.

Drug-Induced Yawning—A Review

Objective:

To review the current literature on drug-induced yawning.

Data Sources:

Literature was accessed through MEDLINE/PubMed (1996-July 2011), International Pharmaceutical Abstracts (1997-July 2011), and EMBASE, using the search terms yawning, drug-induced yawning, and adverse drug reactions.

Study Selection and Data Extraction:

Relevant clinical trials and case reports were selected and included to present background information. Bibliographies of all relevant articles were reviewed for additional citations.

Data Synthesis:

Yawning is a common stereotype behavior with unknown physiologic function that occurs in most vertebrates and humans as early as 15 weeks of intrauterine life. Yawning Is under the control of several neurotransmitters and neuropeptides, Including dopamine, serotonin, oxytocin, and acetylcholine. Among drugs, antidepressants, opioids, dopaminergic agents, benzodiazepines, and induction agents are the main pharmacologic classes associated with yawning.

Conclusions:

Yawning is rarely a serious adverse reaction and is not frequently listed in the drug summary. Most available data are based on case reports, small studies, and older literature. Clinicians should be aware of the agents commonly triggering this behavior.

Inhibitory effects of landiolol and nicardipine on thiopental-induced yawning in humans

PURPOSE

Either the calcium (Ca(2+))-channel blocker nicardipine or the beta(1)-adrenoceptor antagonist landiolol may be intravenously (IV) administered to reduce the hemodynamic responses to tracheal intubation. In this study, we examined the effects of these drugs on the yawning response elicited by intravenous thiopental in humans.

METHODS

After Institutional Review Board approval, 180 consenting American Society of Anesthesiologists (ASA) I or II patients undergoing elective surgery were recruited. In a double-blind, randomized design, three groups of 60 patients each received one of the following intravenous injections: (1) landiolol 0.1 mg/kg (L-group), (2) nicardipine 0.02 mg/kg (N-group), or (3) saline (S-group). In all patients, anesthesia was subsequently induced IV with 4 mg/kg thiopental. Thereafter, the occurrence of the yawning response (characterized by mouth opening) was continuously assessed as the only clinical endpoint for 1 min. Throughout the study, mean arterial blood pressure and heart rate were also recorded at 1-min intervals.

RESULTS

The incidence of the yawning response was lower in both the L-group (6.7%) and the N-group (16.7%) than in the S-group (46.7%) (each, P < 0.01).

CONCLUSIONS

Prior intravenous administration of either a Ca(2+)-channel blocker or a beta(1)-adrenoceptor antagonist can greatly reduce the thiopental-induced yawning response in humans.