Application Of Topical Anesthesia Research Articles

Reflex bradypnea elicited by cigarette smoke inhaled through an isolated larynx

The respiratory reflex responses elicited by laryngeal exposure to cigarette smoke were studied in 23 chloralose anesthetized dogs. A balloon-in-box system was connected to the breathing circuit, which allowed smoke to be inhaled spontaneously through an isolated larynx while preserving its normal respiratory flow and pressure. Our results in this study showed the following. (1) Two tidal breaths of cigarette smoke inhaled through the larynx triggered a mild but consistent bradypnea: expiratory duration (T E) increased from a control of 3.13 ± 0.18 sec (mean ± SEM) to peak of 4.07 ± 0.24 sec. during smoke inhalation. The slowing of respiration occurred only during the period of smoke inhalation and returned quickly toward control after resuming air breathing. (2) No concomitant cardiovascular response was detected in these animals. (3) There was no significant difference in the prolongation of T E between responses to low- and high-nicotine cigarette smoke. (4) The bradypneic response to smoke was completely abolished by application of topical anesthetic (lidocaine hydrochloride) to the mucosa of this airway segment. These results suggest that the smoke-induced reflex bradypnea is probably elicited by a stimulation of laryngeal afferents.

A comparative study of topical anesthesia for laparoscopic sterilization with the use of the tubal ring

A study of 300 women undergoing sterilization via standard or open laparoscopy was conducted at Siriraj Hospital in Bangkok, Thailand; one aspect of the study was designed to determine whether application of topical anesthesia to the fallopian tubes reduces the degree of pain experienced by the patient. The use or nonuse of topical anesthesia was randomized for all cases. Overall, data from this study indicate that application of topical anesthesia to the fallopian tubes tends to diminish surgical pain of patients sterilized by use of either the standard laparoscopy or the open laparoscopy approach and that pain in the recovery period is also reduced for open laparoscopy patients.

Topical anesthesia: H-reflex recovery changes by desensitization of the skin

The H-reflex recovery curve of the soleus muscle was studied in 53 normal subjects before and after the application of topical anesthesia (20% benzocaine) to various skin areas and dermatomes of the lower limb. Skin areas were those overlying the calf, tibialis anterior, quadriceps and hamstrings muscles, and the dermatomes were L 2, L 3, L 4, L 5, S 1, S 2. In 42 subjects the H-reflex initial recovery decreased by 10–80 msec with a mean of 20 ± 17 msec 30 min after application of the topical anesthesia. Also, the test reflex (the second sequential H-reflex) had a faster recovery with less inhibition than that before anesthesia. It was also noticed that the longer the inhibition period before anesthesia, the greater the decrease in recovery time. These observations had no correlation with the skin area or dermatome desensitized by the anesthesia. Furthermore, these observations were not noted when a placebo was sprayed on the skin. The results from this study indicate that input from cutaneous afferents may have an important inhibitory effect on the α-motoneurons of the soleus muscle. This effect is possibly more profound on the large phasic motoneurons. These results are discussed in relation to clinical interpretations of the H-reflex recovery curves.

Mediation of the ocular response to cyclocryocoagulation.

The possible roles of prostaglandins and a neural pathway in the disruption of the blood-aqueous barrier in the rabbit eye after cyclocryocoagulation were studied. Both the preoperative IV administration of the prostaglandin inhibitor acetylsalicylic acid and the application of retrobulbar and topical anesthesia reduced IOP and decreased breakdown of the blood-aqueous barrier, as measured by protein in the aqueous humour. These results imply that the acute response of the animal eye to cyclocryocoagulation is mediated partly by prostaglandins and partly by a neural component resistent an inhibitor of prostaglandin synthesis. When administered together, acetylsalicylic acid and ocular anesthesia yielded a further reduction in postoperative reactions and protein concentrations in the aqueous humour, but were unable to abolish the ocular response completely. The dual ocular mediation to cyclocryocoagulation is apparently due to the combined thermal and mechanical injury caused to ocular structures which synthesize prostaglandins and receive sensory innervation from the trigeminal nerve. The considerable breakdown of the blood-aqueous barrier in cyclocryocoagulation allows leakage of different molecular weight proteins, in equal ratio, into the aqueous humour.

Exploring the information support for speech

A well‐established feature of speech production is that talkers faced with both anticipated and unanticipated perturbations can spontaneously adjust the movement patterns of articulators such that the acoustic output remains relatively undistorted. Less clear is the nature of the underlying mechanism(s) involved. In this study we examined the production of static vowels and vowels embedded in a dynamic speech context in five subjects under normal conditions and a combined condition in which (a) the mandible was fixed via a biteblock, (b) proprioceptive information was reduced via bilateral anaesthetization of the temperomandibular joint, (c) tactile information from oral mucosa was reduced by extensive application of topical anaesthetic, and (d) auditory information was masked by white noise. Analysis of formant patterns revealed minimal distortion of the speech signal under the combined condition. These findings are unfavorable for a predictive simulation model which requires reliable peripheral information (Lindblom et al., 1979) and more in line with recent work suggesting that movement goals may be achieved by muscle collectives that behave qualitatively similar to a nonlinear vibratory system (Fowler et al., 1980; Kelso et al., 1980). [Work supported by NINCDS and BRSG.]

The Effect of Topical Anesthesia on Internal Laryngeal Behavior

Ultra-high speed motion picture laryngeal photography was employed on four subjects to determine the possible effects on the behavior of the internal larynx of orally administered topical anesthesia. Various parameters of laryngeal behavior were investigated, with and without anesthesia, and compared. They included maximum glottal width, glottal length, width of glottis spuria, duration of opening, closing, and closed phases of the vibratory cycle, and glottal area as a function of time. Results were consistent and failed to demonstrate that application of topical anesthesia affects the behavior of the larynx.

The mechanism for gastrin release.

THE VAGUS-denervated antrum pouch releases gastrin in response to contact with food 1 or distention. 2 This response is abolished by the previous local application of topical anesthetics to the antrum mucosa or by the parenteral administration of atropine. 3 These observations indicate that there exists a local mechanism governing gastrin release and suggest that this mechanism is in part dependent on local nervous reflexes. In 1942, Uvnas 4 advanced the concept that vagus impulses cause a direct release of gastrin, and in subsequent years he and his associates secured much additional evidence in its support. It is postulated that the vagi make direct connections with the gastrin-producing cells or with the local gastrin-releasing mechanism. Support for this idea of a vagal release of gastrin was reported from our laboratory 5 as a result of experiments on animals with isolated vagus-innervated antrum pouches. At that time (1957), it was suggested

A catheter for parotid sialography.

VARIOUS techniques for the cannulation of Stensen's duct in the performance of parotid sialography have been utilized. The majority rely on dilatation of Stensen's duct with lacrimal duct dilators prior to definitive cannulation. Few, if any, find the necessity for the application of topical or local anesthesia. Einstein and Perzik¹utilize a short blunt needle (20-23 French) attached to a syringe (Luerlock) for cannulation of the dilated duct and instillation of radiopaque solution. After injection, the needle is removed before roentgenograms are taken. Ross and Castro²utilize a blunt silver needle for the same purpose. Others, including the Head and Neck Service at the Los Angeles Veterans Administration Hospital, insert polyethylene tubing which is taped to the face in the examining room. The patient is then transported to the radiology department for instillation and films. All of the above techniques have their place and usually yield good

COMPARISON OF RADIOISOTOPE SCANNING AND DIFFERENTIAL OXYGEN UPTAKE OF THE LUNGS.

Differential spirometry is an accepted method for evaluating the distribution of pulmonary blood flow between the right and left lungs (1, 2). With this technic an index of the vascular perfusion through each lung is obtained by measuring the percentage of the total oxygen consumption by each lung (3). Recently, a new method of estimating regional pulmonary blood flow by radioisotope scintillation scanning has been described by Wagner et al. (4). Scanning is simple to perform and has been demonstrated to be safe (4), whereas differential spirometry is technically difficult and potentially hazardous (5). This study was undertaken to compare the estimates of pulmonary blood flow to each lung obtained by the two methods. Eighteen patients with unilateral and bilateral lung disease were studied. Sixteen had tuberculosis and 2, bronchiectasis. Differential spirometry was performed with a modified Gaensler-Collins bron-chospirometer, the patient being at rest in the supine position. The two bells of the bronchospirometer were filled with 100 per cent oxygen, and each contained a soda lime carbon dioxide absorption canister. After application of topical cocaine anesthesia, a Carlens catheter with balloons was placed in the trachea according to the technic described by Björkman (1) and Gaensler and Watson (5). When the balloons were inflated, the doublelumen catheter separated the ventilation from each lung. The oxygen uptake of each was determined simultaneously and expressed as a percentage of the total uptake. A radioisotope scan of the lungs was obtained three to ten days after the differential spirometry. During this interval no appreciable changes were observed on the chest roentgenograms. Scanning was performed after the intravenous administration of 0.5 ml. of 1 per cent aggregated human serum albumin tagged with 300 microcuries of I131 according to the technic described by Wagner and his co-workers. The majority of particles ranged in size from 20 to 100 μ and presumably were retained in pulmonary vessels of similar size. Once deposited, the distribution of radioactivity could be determined at any time over the next several hours. For the lung scan the radiation detector was placed over the anterior chest in 6 patients and over the posterior chest in 12. An estimate of the percentage of vascular perfusion to each lung was determined from the scan in the following manner: The central portion of a standard x-ray view-box was used as the light source in a darkened room. A photometer with a 1-in. diameter porthole was placed in direct contact with the radioisotope scan film. A control reading in foot-candles was obtained from a clear area of the film. Each lung was divided into an upper, middle, and lower zone, and 3 readings were taken from different areas in each zone.

Additional safeguard for use in bronchoscopy of tuberculous patient.

For some time, a face shield has been used in many hospitals for protection of the physician during bronchoscopy. It has been impractical to use this face guard during the actual application of topical anesthetics to the pharynx and tracheobronchial tree, because a headlight or headmirror could not be readily worn at the same time. This difficulty has been obviated by riveting an ordinary headmirror to the headpiece of the face shield (see figure). The apparatus shown above has been used in this hospital for several months. It has proved satisfactory as a safeguard for the physician during anesthetization of patients, particularly those with tuberculosis.