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Biomedical subjects

A Kapila

Publications and source records attributed to A Kapila.

At least 19 recordsLinked to original sources
PubMed1998

Clinical assessment of the single use laryngeal mask airway--the LMA-unique.

We conducted a clinical comparison of the laryngeal mask airway (LMA) and the new single use PVC LMA (LMA-Unique) in 100 fasted adult patients undergoing elective surgery. Patients were allocated to one of two groups: group 1 (n = 50) was managed by two consultants and group 2 by two trainee anaesthetists. Airway management was randomized prospectively within each group, and cuff pressure in both devices was maintained at a maximum of 50 mm Hg with upward size substitution if leaks persisted during intermittent positive pressure ventilation (IPPV). Insertion with the recommended technique was successful in all patients (85 first attempt). One patient (group 1) required four attempts for insertion of the LMA-Unique and in one patient (group 2) the LMA-Unique was replaced by a tracheal tube because of persistent leaks during IPPV. In 99 patients IPPV was uneventful. The adjusted mean volume of air for cuff inflation in the LMA-Unique was significantly less in group 1 (P = 0.0013). At fibreoptic laryngoscopic examination, the vocal cords or arytenoids, or both, could be seen in 92% of patients in group 1 and in 90% of patients in group 2. Immediate throat soreness was reported in four patients in group 1 and in seven in group 2. The results suggest that the LMA-Unique was similar in clinical performance to the LMA.

Adult↗
PubMed1998

Airway control during percutaneous dilatational tracheostomy: pilot study with the intubating laryngeal mask airway.

Percutaneous dilatation tracheostomy has become a common procedure for bedside insertion of tracheostomy tubes in the intensive care unit. Management of the airway during the procedure using the laryngeal mask airway (LMA) and other methods has been described. The intubating laryngeal mask airway has several potential benefits for airway management during percutaneous dilatation tracheostomy compared with the LMA. These include the use of both the fibreoptic bronchoscope and tracheal tube if necessary. We report the results of a pilot study of 10 patients that illustrates these advantages.

Adult↗
PubMed1997

The intubating laryngeal mask. I: Development of a new device for intubation of the trachea.

The standard laryngeal mask airway (LMA) functions both as a ventilatory device and as an aid to blind/fibrescopic-guided tracheal intubation. We describe the radiological and laboratory work used to bioengineer a new laryngeal mask prototype, the intubating laryngeal mask airway (ILMA). The aim was to create a new airway system with better intubation characteristics than the LMA. Other design goals were to eliminate the need for head-neck manipulation and insertion of fingers in the mouth during placement. Development was aided by analysis of magnetic resonance images of the human pharynx and laboratory testing with a variety of tracheal tubes. The principal features of this new system are an anatomically curved, rigid airway tube with an integral guiding handle, an epiglottic elevating bar replacing the mask bars, a guiding ramp built into the floor of the mask aperture and a modified silicone tracheal tube developed for use with the device.

Biomedical Engineering↗
PubMed1997

The intubating laryngeal mask. II: A preliminary clinical report of a new means of intubating the trachea.

We have assessed the efficacy of a new laryngeal mask prototype, the intubating laryngeal mask airway (ILMA), as a ventilatory device and blind intubation guide. The ILMA consists of an anatomically curved, short, wide bore, stainless steel tube sheathed in silicone which is bonded to a laryngeal mask and a guiding handle. It has a single moveable aperture bar, a guiding ramp and can accommodate an 8 mm tracheal tube (TT). After induction of anaesthesia with propofol 2.5 mg kg-1 and fentanyl 2.5 micrograms kg-1, the device was inserted successfully at the first attempt in all 150 (100%) patients and adequate ventilation achieved in all, with minor adjustments required in four patients. Placement did not require movement of the head and neck or insertion of the fingers in the patient's mouth. Blind tracheal intubation using a straight silicone cuffed TT was attempted after administration of atracurium 0.5 mg kg-1. If resistance was felt during intubation, a sequence of adjusting manoeuvres was used based on the depth at which resistance occurred. Tracheal intubation was possible in 149 of 150 (99.3%) patients. In 75 (50%) patients no resistance was encountered and the trachea was intubated at the first attempt, 28 (19%) patients required one adjusting manoeuvre and 46 (31%) patients required 2-4 adjusting manoeuvres before intubation was successful. There were 13 patients with potential or known airway problems. The lungs of all of these patients were ventilated easily and the trachea intubated using the ILMA. In 10 of 13 (77%) of these patients, no resistance was encountered and the trachea was intubated at the first attempt; three of 13 (23%) patients required one adjusting manoeuvre. Tracheal intubation required significantly fewer adjusting manoeuvres in patients with a predicted or known difficult airway (P < 0.05). We conclude that the ILMA appeared on initial assessment to be an effective ventilatory device and intubation guide for routine and difficult airway patients not at risk of gastric aspiration.

Adult↗
PubMed1997

The intubating laryngeal mask airway: an initial assessment of performance.

A new prototype of the laryngeal mask airway (LMA), the intubating laryngeal mask airway (ILMA), was used to facilitate tracheal intubation in 100 fasted patients presenting for elective surgery. Alignment of the ILMA with the larynx was assessed fibreoptically before intubation without the investigator performing the intubation being aware of the view score. Ease of intubation correlated with the view obtained and with the degree of manipulation of the ILMA needed to achieve tracheal intubation. Intubation was successful in 93 patients. Of the seven intubation failures, five occurred in the first 20 patients. Conventional connection to the breathing system and ventilation of the lungs of the patients were possible throughout the intubation procedure.

Adult↗
PubMed1996

Reduction of isoflurane minimal alveolar concentration by remifentanil.

BACKGROUND: Remifentanil is a new micro-specific opioid receptor agonist currently under investigation. The interaction between opioids and volatile anesthetics is complex. Defining this interaction provides a basis for more rational dosing schemes when such combinations are used for anesthesia and allows the anesthetic potency of remifentanil relative to other opioids to be determined. METHODS: Two centers enrolled a total of 220 patients. Patients were randomized to receive a target concentration of remifentanil via a computer-assisted continuous infusion device of either 0.0, 0.5, 1.0, 1.5, 2.0, 4.0, 8.0, 16.0, and 32.0 ng/ml initiated before the administration of isoflurane. Patients were also stratified by groups 18-30, 31-55, and 56-65 yr. After induction of anesthesia with isoflurane the initial patient in each dose group was assigned an age-adjusted isoflurane concentration. The isoflurane concentration for each subsequent patient was adjusted according to the up/down technique until a minimum of 12 patients were enrolled in each group. Arterial blood samples for remifentanil whole blood concentrations were obtained. The patient was observed for purposeful movement for up to 1 min after skin incision. The minimum alveolar concentration (MAC) of isoflurane (0 ng/ml remifentanil group) and MAC reduction of isoflurane by remifentanil were determined. RESULTS: The MAC of isoflurane alone was 1.3%. Remifentanil caused an exponential reduction in the MAC of isoflurane with 1.37 ng/ml remifentanil a 77% reduction and 32 ng/ml a 91% reduction of isoflurane MAC. CONCLUSION: The MAC reduction of isoflurane by remifentanil is similar to that produced by other opioids. Although remifentanil was given at extremely high concentrations in the absence of isoflurane, it did not provide adequate anesthesia. A 50% isoflurane MAC reduction is produced by 1.37 ng/ml remifentanil whole blood concentration compared to previously published plasma concentrations of fentanyl of 1.67 ng/ml or sufentanil of 0.14 ng/ml.

Adolescent↗
PubMed1995

Measured context-sensitive half-times of remifentanil and alfentanil.

BACKGROUND: The context-sensitive half-time, rather than the terminal elimination half-life, has been proposed as a more clinically relevant measure of decreasing drug concentration after a constant infusion of a given duration. The context-sensitive half-time is derived from computer modelling using known pharmacokinetic parameters. The modelled context-sensitive half-time for a 3-h infusion of alfentanil is 50-55 min and is 3 min for remifentanil. The terminal elimination half-life is 111 min for alfentanil and 12-30 min for remifentanil. It has not been tested whether the modelled context-sensitive half-time reflects the true time for a 50% decrease in drug concentration or drug effect. METHODS: Thirty volunteers received a 3-h infusion of remifentanil or alfentanil at equieffective concentrations. Depression of minute ventilation to 7.5% ETCO2 was used as a measure of drug effect. Minute ventilation response was measured, and blood samples for drug concentration were taken during and after drug infusion. The recovery of minute ventilation (drug effect) and decrease in blood drug concentration was plotted, and the time for a 50% change was determined. RESULTS: The measured pharmacokinetic context-sensitive half-time for remifentanil after a 3-h infusion was 3.2 +/- 0.9 min, and its pharmacodynamic offset was 5.4 +/- 1.8 min. Alfentanil's measured pharmacokinetic context-sensitive half-time was 47.3 +/- 12 min, and its pharmacodynamic offset was 54.0 +/- 48 min. The terminal elimination half-life modelled from the volunteers was 11.8 +/- 5.1 min for remifentanil and 76.5 +/- 12.6 min for alfentanil. CONCLUSIONS: The measured context-sensitive half-times were in close agreement with the context-sensitive half-times previously modelled for these drugs. The results of this study confirm the value of the context-sensitive half-time in describing drug offset compared to the terminal elimination half-life.

Adult↗
PubMed1988

Neoplastic meningitis with eosinophilic pleocytosis in Hodgkin's disease: a case with cerebellar dysfunction and a review of the literature.

A 31-year-old man had Hodgkin's disease (stage IIA, nodular sclerosis) in apparent remission after radiotherapy. Nine months after the diagnosis of Hodgkin's disease, he developed neoplastic meningitis with eosinophilic pleocytosis and neurologic findings suggestive of peri-fourth ventricle infiltration. Morphologic and surface marker analysis of cerebrospinal fluid cells showed large numbers of T-lymphocytes and Reed-Sternberg variant cells positive for CD15, the Lex hapten expressed on myeloid cells and on a variety of malignant cells. Therapy with intrathecal methotrexate, oral dexamethasone, and cranial irradiation resulted in prompt resolution of his cerebrospinal fluid abnormalities and neurologic deficits. Ten months after the diagnosis of eosinophilic meningitis, systemic relapse of Hodgkin's disease occurred in right iliac and inguinal lymph nodes. The diagnosis, pathogenesis, and therapy of this unusual complication of Hodgkin's disease are reviewed.

Adult↗