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Biomedical subjects

I R Morris

Publications and source records attributed to I R Morris.

10 recordsLinked to original sources
PubMed1994

Fibreoptic intubation.

Although not widely utilized, fibreoptic techniques represent a dramatic advance in the management of the difficult intubation. Particularly suited to the awake patient in the elective setting, fibreoptic intubation can also be useful in selected emergency situations, and can be done under general anaesthesia. In the awake patient fibreoptic intubation maintains a wide margin of safety while producing minimal patient discomfort, but requires adequate local anaesthesia of the airway. Intimate familiarity with the bronchoscope and the anatomy of the upper airway is essential as is careful attention to various aspects of technique. Intubation mannequins can be readily utilized to develop dexterity in bronchoscopic manipulation and intubation workshops are also effective in improving skills. This CME article provides the clinician with a detailed approach to the technique of fibreoptic intubation based on the author's personal experience supplemented by a limited literature review. Fibreoptic intubation is not a difficult skill to master and should be in the armamentarium of all practising anaesthetists.

Anesthesia, General↗
PubMed1988

Pharmacologic aids to intubation and the rapid sequence induction.

Endotracheal intubation usually can be performed in the emergency setting without the use of pharmacologic adjuncts. However, local airway anesthesia lessens patient discomfort, and the use of sedation and muscle relaxants occasionally may be necessary. Rapid sequence induction of general anesthesia adds benefits as well as risks to airway management; used in the circumstance of a full stomach combined with open eye injury or closed head injury associated with raised intracranial pressure, it should be practiced only by physicians appropriately trained and skilled at the procedure.

Anesthesia, Local↗
PubMed1988

Functional anatomy of the upper airway.

Anatomically, the upper airway consists of the pharynx and nasal cavities. However, functionally, the larynx and trachea may be included, and the oral cavity provides an alternate entrance to the respiratory passages. The nose is a pyramidal structure composed of bone and cartilage attached to the facial skeleton, and is divided by a midline septum into the two nasal cavities. The nose functions as a heater and humidifier of inspired gas, a voice resonator, and houses the olfactory receptors. The paranasal sinuses drain into the nasal cavities. An endotracheal tube may be passed through the nose into the trachea when necessary to protect the airway and achieve positive-pressure ventilation. The mouth opens posteriorly into the oropharynx and forms the entrance to the digestive tract as well as an alternate pathway for respiration. It is also involved in phonation. Orotracheal intubation can be used as an alternative to nasal intubation to achieve airway protection and ventilation when necessary; however, variations in upper airway anatomy may make this technique difficult. In supine unconscious persons, backward movement of the tongue and lower jaw may cause airway obstruction. The pharynx is a U-shaped fibromuscular tube extending from the base of the skull to the cricoid cartilage at the entrance to the esophagus. Anteriorly it opens into the nasal cavity, the mouth, and the larynx, which divide it into the naso-, oro-, and laryngopharynx, respectively. The pharynx thus forms a common aerodigestive tract and is intimately involved with the act of swallowing. The larynx consists of a framework of cartilages and fibroelastic membranes covered by a sheet of muscles and lined with mucous membrane. It evolved as a protective valve mechanism at the upper end of the lower airway necessitated by an unusual crossover between the airway and alimentary canal. It functions as an open valve in respiration, a partially closed valve in phonation, and as a closed valve protecting against aspiration during swallowing. The larynx extends from its oblique entrance formed by the aryepiglottic folds, the tip of the epiglottis, and the posterior commissure to the lower border of the cricoid cartilage and bulges posteriorly into the laryngopharynx. The trachea extends from the lower edge of the cricoid cartilage to the carina where it divides into the mainstem bronchi. It is formed by U-shaped cartilaginous rings anteriorly and is closed posteriorly by the trachealis muscle. A properly placed endotracheal tube should have its tip at about midtracheal level.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗
PubMed1984

Colonic motility in the postoperative period.

The effect of a laparotomy on postoperative motility in the colon has been studied in dogs. Movement has been recorded by an electrical impedance method each day after a standard laparotomy. Mean values of movement in the descending colon were reduced, not abolished, for 3 days after operation (preoperative: 34.0%; day 1: 17.9%; day 2: 22.1%; day 3: 23.9%). In contrast, there was no reduction in motility in the transverse colon but a rise in activity on the first postoperative day (preoperative: 39.1%; day 1: 63.3%). It is concluded that a laparotomy does not abolish colonic movement postoperatively and that there is a reduction which affects the distal colon for 3 days.

Abdomen↗
PubMed1983

Changes in small bowel myoelectrical activity following laparotomy.

Recordings of the myoelectrical activity have been obtained from the small intestine of 4 dogs by means of serosally implanted electrodes. The occurrence of the activity front (phase III) of the migrating myoelectrical cycle (MMC) in the recordings obtained each day after abdominal surgery have been compared. No activity fronts were seen on postoperative days 1 and 2. From days 3 to 6 there was a slightly reduced incidence, but from day 7 onwards an activity front was observed in each recording. It is concluded that the normal pattern of cyclic myoelectrical activity in the small intestine is disrupted for at least 2 days following a laparotomy, and the view that small bowel motility returns to normal soon after routine abdominal surgery may be inaccurate.

Animals↗
PubMed1983

Simultaneous recording of myoelectrical activity and resistance from the human colon.

A system used to record myoelectrical activity from the rectosigmoid colon has been modified so that a continuous recording of electrical resistance is obtained simultaneously. Normal subjects, patients with diverticular disease and patients with the irritable colon syndrome have been studied by this method. There were variations in resistance in the form of waves for 74.7, 88.5 and 89.0% of the time in the three groups. These changes were abolished by intravenous glucagon. The predominant frequency of the waves was 2-4 c/min and often coincided with myoelectrical waves of the same frequency. It is concluded that the resistance changes are produced by local movement in the colonic wall at the electrode site and that this technique may be valuable in studying colonic motility.

Colon↗