Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LARYNGITIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1990

[Reflex control on laryngeal functions--vibration effect of the laryngeal mucosa on recurrent laryngeal nerve reflexes].

Electromyographic (EMG) responses of the intrinsic laryngeal muscle have been investigated to clarify reflexogenic laryngeal controls from a viewpoint of its functional significance during phonation. Twenty-five adult cats were anesthetized with intraperitoneal injection of 4ml/kg of a mixture of 10% urethane and 1% alpha-chloralose. Either the internal branch of the superior laryngeal nerve (ISLN) or the recurrent laryngeal nerve (RLN) was carefully dissected and central end of the dissected nerve was electrically stimulated. EMG of the contra-lateral Thyro-Arytenoid muscle (TA muscle) to the stimulation was recorded using a hooked-wire electrode inserted through the laryngeal mucosa. EMG of the TA muscle evoked by the stimulation of the ISLN were analyzed with respect to its latency and discharge pattern inter-collicular brainstem transsected. Together with the stimulation of the RLN, vibratory stimuli were given mainly to the subglottic mucosa as conditioning stimuli. The vibratory frequency was changed from 50Hz to 400Hz step-wisely. Following results were obtained. 1. EMG response of the contra-lateral TA muscle to the stimulation of the ISLN showed two different kinds of latency, approximately 8-10msec, and 40-60msec. 2. After inter-collicular brainstem transsection, evoked response of the latter disappeared. This result indicates that the ISLN-RLN reflex loop consisted of more than two routes, different in the number of synaptic junctions. 3. The vibratory stimuli given to the laryngeal mucosa had facilitatory effect on the reflexive EMG response evoked by the stimulation of the RLN. 4. This facilitatory effect of the vibratory stimuli disappeared after topical anesthesia of the laryngeal mucosa. 5. The facilitatory effect on the reflex responses was partially increased depending on the vibratory frequencies applied. In conclusion, vibratory stimuli to the laryngeal mucosa reflexively modulate the activity of the intrinsic laryngeal muscles.

Animals↗
PubMed1992

[Reflex control of laryngeal functions in the cat: the effect of vibratory stimuli of the laryngeal mucosa on the laryngeal reflex].

To investigate the effect of vibratory stimuli of the subglottic mucosa on the laryngeal reflex, experiments were performed on cats anesthetized with intraperitoneal injection of a mixture of urethane and chloralose. The external branch of the superior laryngeal nerve was cut, while the internal branch of the superior laryngeal nerve (ISLN) was mounted on stimulating electrodes. Electromyograms (EMG) were recorded from the contralateral thyreoarytenoid (TA), posterior cricoarytenoid (PCA), lateral cricoarytenoid (LCA), and cricothyreoid (CT) muscles. When the ISLN was electrically stimulated, the laryngeal reflex was induced. Short latency (early) and long latency (late) responses were observed in TA, PCA, LCA, and CT. Then, vibratory stimuli were applied to the surface of the subglottic mucosa. Vibratory frequencies used in this study were varied stepwise from 100 Hz to 400 Hz, with the amplitude adjusted at 20 microns. Vibratory stimuli had no effect on early responses but did, however, exert a facilitatory effect on late responses of TA and LCA in the transitional phase from inspiration to expiration and on late responses of PCA in the inspiratory phase. After denervation of ISLN, the vibratory effect on late responses disappeared completely. No significant vibratory effect was observed on CT in any respiratory phase. These results suggest that vibratory stimuli applied to the surface of the subglottic mucosa reflexively facilitate the laryngeal reflex and that ISLN afferents and respiratory drive modulate the laryngeal reflex.

Animals↗
PubMed1989

[DNA content in laryngeal keratosis, laryngeal cancer and normal laryngeal epithelium].

The DNA content in laryngeal precancerous lesion, laryngeal keratosis, laryngeal carcinoma and normal laryngeal epithelium had been measured in order to study the relationship between histopathologic picture and DNA content. The results showed that the DNA content in keratotic tissue increased to varying degrees as compared with the normal tissue. The DNA content in laryngeal cancer increased distinctly, being much higher than that in normal and keratotic tissues.

DNA↗
PubMed1998

Functional outcomes following treatment for advanced laryngeal cancer. Part I--Voice preservation in advanced laryngeal cancer. Part II--Laryngectomy rehabilitation: the state of the art in the VA System. Research Speech-Language Pathologists. Department of Veterans Affairs Laryngeal Cancer Study Group.

This two-part investigation assessed functional outcomes related to communication (including amount of speech therapy), swallowing and eating, and employment status for patients who received one of the two treatment modalities for advanced laryngeal cancer (stage III or IV laryngeal squamous cell carcinoma) in Veterans Administration Cooperative Study #268. One hundred sixty-six patients were randomized to primary surgery (laryngectomy) and radiotherapy (RT), and 166 to induction chemotherapy (CT) and RT. The first investigation dealt with examining and comparing functional outcomes for patients in the two treatment arms of the main study. Results showed clearly that patients with advanced laryngeal cancer are better off from the standpoint of speech communication if they can be treated for this disease without removal of the larynx. In contrast, there were few significant differences between patient groups for other non-speech-related measures. The second investigation focused on communication-related outcomes associated with the rehabilitation of total laryngectomy patients. Results revealed that only relatively small percentages of total laryngectomy patients (6%) developed usable esophageal speech or remained nonvocal (8%), and that a majority of patients ended up as users of artificial electrolarynx (55%) or tracheoesophageal (31%) speech. The results from both investigations are discussed with respect to factors that can influence the rehabilitation process and long-term outcome status of patients who are treated for advanced laryngeal cancer with these two strategies.

Adult↗
PubMed2003

Pharyngeal mucosal pressures with the laryngeal tube airway versus ProSeal laryngeal mask airway.

We tested the hypothesis that mucosal pressures are higher for the laryngeal tube airway trade mark than the ProSeal laryngeal mask airway. Fifteen fresh cadavers were studied. Microchip pressure sensors were attached to the laryngeal tube airway and ProSeal laryngeal mask airway at four similar anatomical locations (base of tongue, lateral pharynx, posterior pharynx and posterior hypopharynx) and three dissimilar locations (laryngeal tube airway trade mark, anterior and lateral hypopharynx; ProSeal laryngeal mask airway, pyriform fossa). The cuff volume (laryngeal tube airway, < or = 140 ml; ProSeal laryngeal mask airway, < or = 30 ml) was adjusted until the oropharyngeal leak pressure was 15 cm H2O and the mucosal pressures recorded. This was repeated at an oropharyngeal leak pressure of 20, 25 and 30 cm H2O. Mucosal pressures in the lateral pharynx were always similar. Mucosal pressures at the base of tongue and posterior pharynx were similar for the laryngeal tube airway and ProSeal laryngeal mask airway at 15 and 20 cm H2O, but were higher for the laryngeal tube airway at 25 cm H2O at 30 cm H2O. Mucosal pressures in the posterior hypopharynx were always higher for the laryngeal tube airway (all: p < 0.03). Mean mucosal pressures for the laryngeal tube airway ranged from 8-31, 2-13 and 15-41 cm H2O for the base of tongue, lateral pharynx and posterior pharynx (proximal cuff) respectively and 3-7, 3-7 and 7-18 cm H2O for the anterior, lateral and posterior hypopharynx (distal cuff) respectively. Mean mucosal pressures for the ProSeal laryngeal mask airway ranged from 6-23, 3-10, 8-25, 6-17 and 2-8 cm H2O for the base of tongue, lateral pharynx, posterior pharynx, pyriform fossa and posterior hypopharynx respectively. We conclude that mucosal pressures are higher for the laryngeal tube airway, particularly when oropharyngeal leak pressure greater than 25 cm H2O. This suggests that mucosal ischemic injury will be more common with the LTA than the PLMA.

Aged↗
PubMed1996

Laryngeal abductor function after recurrent laryngeal nerve injury in cats.

OBJECTIVE: To determine the influence of severity of neural injury of t he recurrent laryngeal nerve on recovery of laryngeal abductor function and the importance of synkinesis. DESIGN: The recovery of laryngeal abductor function was studied in 30 cats after crushing (second-degree injury) or transection followed by neurorrhaphy (fifth-degree injury) of the recurrent laryngeal nerve, with a reinnervation period of 10 weeks. MAIN OUTCOME MEASURES: Recovery of laryngeal abductor function was evaluated by videolaryngoscopy of spontaneous laryngeal abduction during respiration and electromyography of the posterior cricoarytenoid and vocalis muscles. Neural lesions were applied unilaterally, and recovery of laryngeal function was compared with the contralateral unimpaired hemilarynx. Reinnervation was confirmed by histologic examination. RESULTS: After the recurrent laryngeal nerve was crushed, laryngeal abductor function was similar to normal after a 10-week reinnervation period in 19 of the 20 cats; after neurorrhaphy, no notable recovery of laryngeal abduction resulted in any of 10 cats. Electromyographic recordings disclosed synkinesis after neurorrhaphy and recovery of normal activity patterns after crush injuries. CONCLUSIONS: Severity of neural injury to the recurrent laryngeal nerve influences the recovery of laryngeal abductor function. Damage to the endoneurium leads to misdirection of regenerating axons, inappropriate reinnervation, and synkinesis. No effective laryngeal function can then be expected.

Animals↗
PubMed2002

Comparison of times to achieve tracheal intubation with three techniques using the laryngeal or intubating laryngeal mask airway.

We compared the times to intubate the trachea using three techniques in 60 healthy patients with normal airways: (i) fibreoptic intubation with a 6.0-mm reinforced tracheal tube through a standard laryngeal mask airway (laryngeal mask-fibreoptic group); (ii) fibreoptic intubation with a dedicated 7.0-mm silicone tracheal tube through the intubating laryngeal mask airway (intubating laryngeal mask-fibreoptic group); (iii) blind intubation with the dedicated 7.0-mm silicone tracheal tube through the intubating laryngeal mask airway (intubating laryngeal mask-blind group). Mean (SD) total intubation times were significantly shorter in the intubating laryngeal mask-blind group (49 (20) s) than in either of the other two groups (intubating laryngeal mask-fibreoptic 74 (21) s; laryngeal mask-fibreoptic group 75 (36) s; p < 0.001). However, intubation at the first attempt was less successful with the intubating laryngeal mask-blind technique (15/20 (75%)) than in the other two groups (intubating laryngeal mask-fibreoptic 19/20 (95%) and laryngeal mask-fibreoptic 16/20 (80%)) although these differences were not statistically significant. We conclude that in this patient group, all three techniques yield acceptable results. If there is a choice of techniques available, the intubating laryngeal mask-blind technique would result in the shortest intubation time.

Anesthesia, Dental↗
PubMed1993

[Anesthesia and laryngeal muscle, especially intrinsic laryngeal muscles].

The intrinsic laryngeal muscles are highly specialized for phonation, respiration and sphincter activity. The muscles are disposed between three unpaired cartilages (the thyroid, cricothyroid and epiglottic) and the paired arytenoid cartilages. These laryngeal muscles, which are striated in character, are bilaterally disposed and can be grouped as adductors and abductors of the glottis and tensors of the vocal cords. The motor neurons for the intrinsic laryngeal muscles are located in the caudal half of the nucleus ambiguous. The intrinsic laryngeal muscles receive motor nerve supply from the external branches of the superior laryngeal and recurrent nerves on each side. The external branch of the superior laryngeal nerve serves in motor innervation of the cricothyroid muscle, while the other laryngeal muscles receive a motor innervation from the recurrent nerve. Compared with limb skeletal muscles, the intrinsic laryngeal muscle have unique morphologic and histochemical characteristics. In general, the intrinsic laryngeal muscle fibers contain greater percentages of histochemically type 1 fibers than limb skeletal muscles. In addition, morphometrical studies of the subneural apparatus at the neuromuscular junctions of the intrinsic laryngeal muscles demonstrate the difference between the morphological features of the nerve endings and the distribution pattern of the motor end-plates of the laryngeal muscles and those of the limb skeletal muscles. Finally, the influence of anesthetic drugs including neuromuscular blocking agents on the intrinsic laryngeal muscles is discussed. The gross anatomical features such as the motor innervation, localization of the neurons for the motor nerve fibers, and arrangement and characteristics of the motor end-plates of the intrinsic laryngeal muscles are described based on a review of literature and our current investigations.

Anesthesia↗
PubMed1991

An experimental study on the laryngeal electromyography and visual observations in varying types of surgical injuries to the unilateral recurrent laryngeal nerve in the neck.

A series of varying types of surgical injuries to the recurrent laryngeal nerve, including half section, double crush, suture ligation, and complete section of the nerve, was investigated in dogs by correlating clinical and electromyographic findings. The state of recovery from palsy was evaluated by recording the electromyography from the affected laryngeal muscles as well as by observing the movements of the vocal cords. Six electromyography patterns were recorded from the affected muscles following injuries to the recurrent laryngeal nerve. There is a close relationship between the electromyography patterns and the types of nerve injuries. Within 3 months after injuries of the recurrent laryngeal nerve, the electromyography motor unit potentials in the involved intrinsic laryngeal muscles and vocal cord movements on the side of the nerve injury were back to normal in the groups of dogs in which the recurrent laryngeal nerves were partially sectioned and doubly crushed; the electromyography potentials and vocal cord motion on the affected side did not return to normal in the group of dogs in which the recurrent laryngeal nerves were permanently ligated with suture. In the group of dogs which had had a complete section of the recurrent laryngeal nerve, no recovery of both electromyography and vocal cord function on the affected side was observed 6 months after injury of the recurrent laryngeal nerve. This study showed that the frequency of the regenerated potentials recorded from the affected muscles is related to the types and degrees of injuries to the recurrent laryngeal nerve. Recovery from recurrent laryngeal nerve palsy is complete within 3 months after nerve impairment if over half of the nerve fibers of the impaired nerve are maintained intact without degeneration. Moreover, the period from onset to complete recovery from palsy was remarkably short, less than 2 months. The most appropriate time for the electromyography examination to evaluate the degrees of the nerve injury and to anticipate the prognosis of recurrent laryngeal nerve palsy was proposed.

Animals↗
PubMed2002

[Laryngeal reinnervation for unilateral recurrent laryngeal nerve injuries caused by thyroid surgery].

OBJECTIVE: To explore the protocols and effects of laryngeal reinnervation for unilateral recurrent laryngeal nerve (RLN) injury caused by thyroid surgery. METHODS: Different protocols of laryngeal reinnervation were performed upon 29 patients with unilateral recurrent laryngeal nerve injury caused by thyroid surgery, just coming on to with a course of 2 years, including nerve decompression upon 8 cases, end to end anastomosis of recurrent laryngeal nerve upon 6 cases, and anastomosis of main branch of ansa cervicalis to recurrent laryngeal nerve upon 15 cases. All were been subjected to preoperative and postoperative voice recording, acoustic analysis, videolaryngoscopy, stroboscopy and electromyography. RESULTS: Nerve decompression had restored the normal functional adductory and abductory motion of the vocal cord in 5 patients with a course of less than four months. Although functional motion of vocal cord had not been recovered in three patients who received nerve decompression, 2 being with a course of longer than 4 months and one with a course of less than 4 months, and in all cases who received ansa cervicalis anastomosis and end to end anastomosis of recurrent laryngeal nerve, these procedures resulted in medialization of vocal cords except in two cases, one receiving ansa cervicalis anastomosis, and the other receiving end to end anastomosis of RLN. Acoustic parameters (Jitter, Shimmer, NNE) measured 6 months after operation of any kind all returned to normal, however, without significant difference among different groups (P > 0.05). The amplitude of evoked potential of reinnervated laryngeal muscles was significantly greater in the group of nerve decompression than in the group of end to end anastomosis of RLN and group of ansa cervicalis anastomosis (both P < 0.05). However, the amplitude of evoked potential of reinnervated laryngeal muscles between the latter two groups was not significantly different (P > 0.05). Except in one case in the end to end anastomosis of RLN group and one case in the ansa cervicalis anastomosis group, the mass and tension of the reinnervated vocal cord became much the same as the contralateral normal vocal cord and symmetric vibration of the vocal cords and physiological phonation were recovered in all cases. CONCLUSION: (1) Nerve decompression is the best procedure in laryngeal reinnervation. (2) Main branch of ansa cervicalis anastomosis and end to end anastomosis of RLN effectively restore the laryngeal vocalization. (3) Selection of the laryngeal reinnervation protocols should depend on the course, severity and type of nerve injury.

Adult↗
PubMed2001

Fibreoptic views through the laryngeal mask and the intubating laryngeal mask.

BACKGROUND AND OBJECTIVE: The intubating laryngeal mask (intubating laryngeal mask airway) was designed to facilitate blind intubation. Its value as an adjunct to fibreoptic laryngoscopy has not been evaluated. This study compares the intubating laryngeal mask airway with the standard laryngeal mask airway as conduits for fibreoptic laryngoscopy. METHODS: The fibreoptic view of the laryngeal inlet was graded via both devices in 60 anaesthetized patients. The fibreoptic view through the intubating laryngeal mask airway was assessed after the central epiglottic elevator bar had been lifted out of the field of vision by an 8-mm Euromedical tracheal tube, which was inserted to a depth of 18 cm. The fibreoptic view from the aperture bars of the laryngeal mask was recorded. RESULTS: The vocal cords were viewed less frequently through the intubating laryngeal mask airway (52%) than through the laryngeal mask airway (92%) [difference = 40% (95% CI = 26% to 54%), P < 0.0001]. CONCLUSION: The view of the laryngeal inlet is better through the laryngeal mask airway than through a tracheal tube inserted to 18 cm in the intubating laryngeal mask.

Adolescent↗
PubMed2001

The laryngeal mask and VBM laryngeal tube compared during spontaneous ventilation. A pilot study.

BACKGROUND AND OBJECTIVE: The laryngeal tube is a variant of the oesophageal obturator airway. The manufacturer claims that it is an alternative to ventilation with a facemask, laryngeal mask or endotracheal tube. To date, published studies have only involved controlled ventilation. We wished to find out if its use in spontaneous ventilation was equivalent to using the laryngeal mask airway. METHODS: We have compared the laryngeal tube with the laryngeal mask in a randomized prospective study involving patients breathing spontaneously under general anaesthesia. Criteria and a scoring system were used for the comparison. A sequential analysis chart with P=0.01 was chosen for each of two anaesthetists. RESULTS: Only seven and 10 pairs of patients were required to indicate that the laryngeal tube was poorer at airway maintenance than the laryngeal mask. Of the 17 patients who had received the laryngeal tube, successful airway maintenance was only possible in seven. In the remaining 10 patients, the laryngeal tube was abandoned and the rescue airway was the laryngeal mask in all cases. All 17 patients randomized to the laryngeal mask were successfully managed. CONCLUSIONS: We conclude that the laryngeal tube is not a satisfactory device for management of the airway during spontaneous ventilation.

Adult↗
PubMed2003

Laryngeal resistance before and after minor surgery: endotracheal tube versus Laryngeal Mask Airway.

BACKGROUND: The placement of an endotracheal tube (ETT) may promote laryngeal swelling, which is an important cause of upper airway obstruction after extubation. The authors hypothesized that laryngeal swelling after ETT placement increases laryngeal resistance and tested that hypothesis by comparing postoperative laryngeal patency between patients with ETT placement and those with a Laryngeal Mask Airway trade mark (LMA). METHODS: Fourteen adult patients who underwent elective minor surgeries were randomly allocated to two groups whose airway would be managed through ETTs (the ETT group) or LMAs (the LMA group) during the surgery. While maintaining at sevoflurane 1 minimum alveolar concentration, the authors measured laryngeal resistance before and after surgery, during both spontaneous breathing and mechanical ventilation under complete paralysis. In addition, they endoscopically measured the vocal cord angle under complete paralysis. RESULTS: In association with marked swelling of the vocal cords, the vocal cord angle significantly decreased after surgery in the ETT group, whereas the angle did not change in the LMA group. Laryngeal resistance during mechanical ventilation significantly increased only in the ETT group. Laryngeal resistance during spontaneous breathing significantly increased after surgeries in both groups. CONCLUSIONS: Postoperative laryngeal resistance increases at least in part because of laryngeal swelling in patients with ETT placement, whereas alteration of laryngeal neural control mechanisms has been also indicated. The use of the LMA trade mark has an advantage over ETT placement in order to avoid postoperative laryngeal swelling.

Adult↗
PubMed2002

The laryngeal tube compared with the laryngeal mask: insertion, gas leak pressure and gastric insufflation.

BACKGROUND: We have compared the laryngeal tube and laryngeal mask in 22 patients for the success rate of insertion, gas leak pressure and the incidence of gastric insufflation. METHOD: In a randomized, crossover design, the laryngeal tube and laryngeal mask were inserted in turn after induction of anaesthesia and neuromuscular block. The cuffs were inflated until the intracuff pressure reached 60 cm H(2)O. We measured adequacy of ventilation and the minimum airway pressure at which gas leaked around the cuff. The presence or absence of gastric insufflation was studied at an inflation pressure of 20 cm H(2)O. RESULTS: It was possible to ventilate through the laryngeal tube in 21 patients and through the laryngeal mask in 21 patients. The mean leak pressure for the laryngeal tube (26 (SD 5) cm H(2)O) was significantly greater than that for the laryngeal mask (19 (4) cm H(2)O) (P<0.01; 95% confidence intervals for mean difference: 5.3-10.2 cm H(2)O). Gastric insufflation did not occur when the laryngeal tube was used and was noted in three patients when the laryngeal mask was used. CONCLUSION: The laryngeal tube provides a better seal in the oropharynx than the laryngeal mask.

Adolescent↗
PubMed1996

[Serum dihydrotestosterone versus total testosterone values of patients with laryngeal carcinomas and chronic laryngitis].

BACKGROUND: Paradoxically, the highest incidence of laryngeal carcinomas occurs in the presence of reduced gonadal androgen levels associated with ageing, while the stimulating effects of androgens on the laryngeal mucosa and their tumors have been reported in the literature. The decrease of testosterone values and nearly unchanged values of dihydrotestosterone in serum and tissues of elderly men have been documented in recent endocrinological literature. This trial was performed in an effort to resolve this apparent contradiction. METHODS: Twenty-two male laryngeal cancer patients and ten patients with chronic laryngitis were examined, and their dihydrotestosterone and total testosterone values in serum recorded. Blood sampling was performed for each patient between 7 and 10 a.m. before commencement of tumor therapy. An enzyme immunoassay (Serono automat SR 1) was used to determine the values of total testosterone, whereas a 5 alpha dihydrotestosterone (H 3)- radio-immuno-assay was carried out after serum extraction. RESULTS: The total testosterone values of the laryngeal cancer patients were found to be significantly lower than the values in the laryngitis group, but the mean levels of dihydrotestosterone were found to be comparable within both groups. However, the scattering of dihydrotestosterone values was much higher in the group of laryngeal cancer patients than in the laryngitis group. CONCLUSIONS: The average age of the cancer patients examined was 10 years higher than in the laryngitis group. The present results partially correspond to the reports in the endocrinological literature. Together with experimental results regarding the effects of pure substances of testosterone and dihydrotestosterone on permanent laryngeal cancer cell lines, the current results confirm the importance of the imbalance between testosterone and dihydrotestosterone as a cofactor in the development of squamous cell carcinomas of the larynx. Testosterone substitution as well as blocking of 5 alpha-reductase, the enzyme which facilitates formation of dihydrotestosterone from testosterone, are regarded as promising therapeutic opportunities for the future, especially for patients with laryngeal preneoplasias or as recurrence prophylaxis after primary tumor therapy.

Aged↗
PubMed1996

Effect of a second laryngeal stimulation during recovery from the laryngeal chemoreflex.

The laryngeal chemoreflex is a potential mechanism for sudden infant death. In experimental protocols in which a full recovery is allowed between stimuli, no laryngeal chemoreflex responses result in a fatal outcome. In the clinical situation there are no controls to prevent repeated laryngeal stimulation before a full recovery. The effect of a laryngeal stimulus applied during or soon after a laryngeal chemoreflex-induced apnea was investigated. Eighteen piglets were divided into groups aged 10 to 12 days, 17 to 21 days, and 32 to 36 days. Laryngeal stimulation was performed under normoxic conditions with water applied to the mucosa. Baseline respiratory and cardiovascular response data were measured. After recovery an initial stimulation was applied, followed by a second stimulation during the apnea or 5, 30, 60, or 120 seconds after restoration of breathing. No profound apneas occurred with baseline laryngeal stimulation. In piglets aged 32 to 36 and 17 to 21 days, a second laryngeal stimulus resulted in a shortened apnea duration. The response varied in piglets aged 10 to 12 days with profound apneas observed in 2 of 6 subjects and 4 of 30 trials. Piglets aged 17 to 36 days are less susceptible to the laryngeal chemoreflex during the immediate recovery period. In piglets aged 10 to 12 days, the laryngeal chemoreflex response may be more severe after a second stimulus.

Age Factors↗
PubMed2000

Laryngeal C-fiber afferents are not involved in the apneic response to laryngeal wood smoke in anesthetized rats.

Laryngeal exposure to wood smoke in rats evokes a reflex apnea which is mediated through superior laryngeal afferents (J. Appl. Physiol. 83: 723-730, 1997). To study the role of laryngeal C-fiber afferents in eliciting this response, capsaicin aerosol (0.05 - 0.2 microg/ml) and 5 ml of wood smoke were delivered separately into a functionally isolated larynx of anesthetized Sprague-Dawley rats at a constant flow rate of 1.4 ml/s, while animals breathed spontaneously. Studies were repeated after either an intravenous injection of ruthenium red (2 mg/kg; n = 8), a perineural capsaicin treatment (200 microg/ml for 5 min; n = 8) of the superior laryngeal nerves, or a perineural sham treatment (n = 8); Ruthenium red inhibits the stimulation of afferent C-fiber nerve endings by capsaicin, whereas perineural capsaicin treatment selective blocks the conduction of C-fiber afferents. Either ruthenium red or perineural capsaicin treatment abolished the apneic response to laryngeal capsaicin, but did not significantly affect the apneic response to laryngeal wood smoke. Furthermore, the apneic responses to both types of irritants were not significantly altered by perineural sham treatment, yet were completely eliminated by a subsequent denervation of superior laryngeal nerves. Our results suggest that superior laryngeal C-fiber afferents are not involved in eliciting the reflex apneic response to laryngeal wood smoke in anesthetized rats. It is speculated that this response may result mainly from the stimulation of myelinated afferents, possibly laryngeal irritant receptors.

Aerosols↗
PubMed1999

Second laryngeal cancers in previously treated larynges.

OBJECTIVES: To review the management and outcome of patients with new second primary cases of laryngeal cancer occurring more than 3 years after the initial cancer was treated. STUDY DESIGN: Retrospective review of 855 patients with newly diagnosed and treated laryngeal cancers. METHODS: Charts were reviewed and tabulated for occurrence of second primary laryngeal tumors, method of treatment for the index and second primary laryngeal tumors, and effect of smoking status or cessation of smoking. RESULTS: Of the 855 patients, 532 patients retained their larynx; of these 377 lived more than 3 years and thus were at risk for a second new primary cancer. Of these 377 patients at risk, 19 or 5.1% developed second primary tumors. The rate of second primary disease was lower in patients whose index laryngeal cancer was treated by irradiation (4.3%) compared with those treated surgically (9.2%). However, surgical treatment of second primary laryngeal tumors resulted in far higher rates of laryngeal voicing (82%) compared with irradiation (33%). CONCLUSION: When possible, management of the index primary tumor by endoscopic resection has resulted in the highest future retention of laryngeal speech, leaving all treatment options available should a second laryngeal cancer occur. Lifelong follow-up of patients with laryngeal cancer for secondary primary tumors is important. Second primary tumors were equally distributed between patients who continued to smoke and ceased to smoke after their index primary lesion was diagnosed.

Carcinoma, Squamous Cell↗