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Biomedical subjects

J H Pennant

Publications and source records attributed to J H Pennant.

At least 19 recordsLinked to original sources

The dose-response relationship of ondansetron in preventing postoperative emesis in pediatric patients undergoing ambulatory surgery.

BACKGROUND: Postoperative nausea and vomiting is a distressing anesthetic complication that may delay discharge after ambulatory surgery. Effective prophylaxis for postoperative nausea and vomiting can be achieved in adults with lower doses of ondansetron, a 5-hydroxytryptamine subtype 3 receptor antagonist, compared with chemotherapy-induced emesis. However, the doses of ondansetron used in preventing postoperative nausea and vomiting in children are based on data from chemotherapy-induced emesis. The dose-related efficacy of intravenous ondansetron in the prophylaxis of postoperative emesis in the pediatric outpatient population was determined. METHODS: In a double-blind, randomized placebo-controlled study, 130 patients (mean age 5.7 +/- 3.4 yr) received placebo, 10, 50, or 100 micrograms/kg ondansetron during a standardized anesthetic. Episodes of postoperative vomiting or retching were recorded. RESULTS: Intravenous ondansetron in a dose of 50 micrograms/kg was more effective than placebo or a dose of 10 micrograms/kg in controlling the incidence and frequency of emesis in the hospital and during the first 24 postoperative hours. Increasing the dose of ondansetron to 100 micrograms/kg intravenously did not significantly reduce the incidence or frequency of emesis compared to 50 micrograms/kg intravenously. CONCLUSIONS: Intravenous ondansetron in a dose of 50 micrograms/kg is as effective as larger doses for the prophylaxis of emesis in children undergoing surgical procedures known to be associated with an increased risk for postoperative nausea and vomiting.

Ambulatory Surgical Procedures

Use of the laryngeal mask airway after oesophageal intubation.

We have compared insertion of a tracheal tube and laryngeal mask airway (LMA) both with and without the presence of a tube in the oesophagus in 20 ASA I and II patients undergoing elective laparoscopy. After induction of anaesthesia and neuromuscular block, we measured the times for an experienced anaesthetist to correctly position both an LMA and a tracheal tube with and without a tube in the oesophagus. The time to intubation was significantly less with the LMA than with the tracheal tube, both with and without an oesophageal tube in place (P < 0.05). We conclude that if a tracheal tube is placed unintentionally in the oesophagus, an LMA may be used subsequently to provide rapid and effective oxygenation of the patient.

Adolescent

Tracheal tube cuff inflation as an aid to blind nasotracheal intubation.

We have assessed the efficacy of tracheal tube cuff inflation in the oropharynx as an aid to blind nasotracheal intubation in 20 ASA I and II patients undergoing elective oral surgery. The trachea was intubated once using the technique of tracheal tube cuff inflation in the oropharynx and once keeping the tracheal tube cuff deflated throughout the manoeuvre. With the cuff deflated, intubation was successful in nine of 20 (45%) patients; in eight of 20 (40%) it was successful on the first attempt. With the tracheal tube cuff inflated, intubation was successful in 19 of 20 patients (95%), 15 of 20 (75%) of these on the first attempt. The success rates were significantly different (P < 0.01). Times to intubate were not significantly different (P > 0.05). We conclude that, in normal patients, tracheal tube cuff inflation in the oropharynx increases the success rate of blind nasotracheal intubation.

Adolescent

The laryngeal mask airway. Its uses in anesthesiology.

The LMA is a useful airway device for most adult and pediatric patients. It is easy and atraumatic to insert, with minimal somatic and autonomic responses from the patient. It is a suitable alternative to the face mask and to tracheal intubation in a wide variety of clinical situations. In addition, the LMA facilitates blind and fiberoptic techniques of intubation, but its role in the emergency scenario has yet to be established. The preliminary experience gained with this device in Europe and Australasia suggests that it may also transform contemporary anesthetic practice in the United States.

Anesthesiology

Comparison of the endotracheal tube and laryngeal mask in airway management by paramedical personnel.

An evaluation of the laryngeal mask airway (LMA) as a means of airway support when used by paramedical personnel was performed. Forty medical and paramedical students attempted to intubate the tracheas of 40 healthy anesthetized adults with the LMA and a cuffed endotracheal tube (ETT). The number of attempts to achieve correct placement and the time taken to adequately ventilate the lungs were recorded for both devices. End-tidal carbon dioxide was detected significantly sooner after commencement of the intubation attempt using the LMA (mean 38.6 s) compared with the ETT (mean 88.3 s, P less than 0.0001). Ninety-four percent of the students successfully ventilated the lungs on their first attempt with the LMA, whereas only 69% intubated the trachea on their first attempt with the ETT (P less than 0.01). Five students were unable to intubate the trachea after three attempts with the ETT, but all positioned the LMA satisfactorily on their first try in a mean time of 40 s. We conclude that unskilled operators with minimal training can safely and successfully ventilate unconscious patients more rapidly using the LMA than the ETT. These results suggest the LMA should be available in all areas where resuscitation is performed.

Adolescent