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Biomedical subjects

C Verghese

Publications and source records attributed to C Verghese.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

The laryngeal mask airway in emergency medicine, neonatal resuscitation, and intensive care medicine.

In assessing the potential role of the LMA outside the operating room, the risks of a less secure airway must be balanced against the benefits of ease of training, success and speed of insertion, no need for direct visualization of laryngeal structures, and lesser need for ancillary equipment. The LMA has a role as an alternative to FMV in CPR when personnel skilled in tracheal intubation are not available. When skilled intubators are present, it has an important role as an alternative airway when intubation has been impossible. These roles extend to the prehospital setting, with an additional specific indication for its use when access to a patient is limited making tracheal intubation impossible. The LMA is incorporated into advanced life support training and as such should be regarded as a device providing temporary airway support, rather than a replacement for a tracheal tube. The LMA, and possibly also the ILM, should be standard equipment carried by prehospital trauma teams and by all those attending victims in the field.

Adult↗
PubMed1998

Absence of changes in antidiuretic hormone, angiotensin II, and atrial natriuretic peptide with clozapine treatment of polydipsia-hyponatremia: 2 case reports.

BACKGROUND: Polydipsia-hyponatremia is a poorly understood disorder that causes considerable mortality and morbidity. Hyponatremia in polydipsia-hyponatremia has been attributed to disturbances in antidiuretic hormone (ADH) function. Improvements in polydipsia-hyponatremia during clozapine treatment offered the chance to see if levels of ADH and other hormones associated with osmoregulation changed with improvement in biochemical and clinical measures of polydipsia-hyponatremia. METHOD: In this preliminary, longitudinal study, we studied 2 male schizophrenic patients (DSM-III-R) who had polydipsia-hyponatremia. Measures were (1) biochemical and clinical: serum sodium and osmolality, urine osmolality and specific gravity, normalized diurnal weight gain, and estimated urine volume and (2) endocrine: ADH, angiotensin II, atrial natriuretic peptide, and prolactin. Measures were collected during 2 months of baseline (typical neuroleptic) and 6 months of clozapine treatment. RESULTS: Single-case statistical procedures showed significant changes in sodium levels (a.m. and p.m.), estimated urine volume, and a.m. urine specific gravity in both patients and significantly decreased diurnal weight gain in 1 patient. Both serum and urine osmolality showed improvement, but values did not reach statistical significance. Low baseline ADH levels persisted through 6 months of clozapine treatment and showed no changes in the context of improvements in serum sodium and osmolality. No significant changes were seen in levels of angiotensin II and atrial natriuretic peptide. CONCLUSION: Given the limitations of this study, there is some evidence to suggest that the improvements in serum sodium and osmolality during clozapine treatment of polydipsia-hyponatremia may not be related to serum levels of ADH, although altered ADH receptor function cannot be ruled out. These data need to be extended in larger samples.

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↗
PubMed1997

Laryngeal mask airway and the incidence of regurgitation during gynecological laparoscopies.

We studied the incidence of regurgitation in 100 patients undergoing elective gynecological laparoscopies under general anesthesia with intermittent positive pressure ventilation using a laryngeal mask airway (LMA). Patients ingested methylene blue capsules 10-15 min before induction of anesthesia. After induction and insertion of an LMA using the recommended insertion technique, a fiberoptic examination of the larynx was made for traces of dye and to site a pH probe in the bowl of the LMA for continuous monitoring. LMA insertion was successful in all patients within two attempts (95 at first attempt). Fiberoptic examination revealed the vocal cords or cords and posterior or anterior epiglottis in 96 and no trace of dye in 99 patients. One patient regurgitated dye immediately after induction, and the stain was seen on the LMA after removal. The remaining 99 LMAs were not stained. Thirty patients were randomly selected for fiberoptic examination of the laryngopharynx before neuromuscular block was antagonized. Methylene blue staining did not occur in any of these patients. In 91 patients with complete pH data, regurgitation (pH < 4.0) did not occur. The 95% confidence limit for a true probability of regurgitation in this study is 0.041 or a true rate of regurgitation of less than 4.1%. A larger study would be required to possibly demonstrate a lower incidence of regurgitation. This study confirms the clinical impression that the incidence of regurgitation during laparoscopies with a LMA is extremely low.

Adolescent↗
PubMed1996

Clozapine withdrawal effects and receptor profiles of typical and atypical neuroleptics.

Withdrawal effects of neuroleptics have not received much attention. Clozapine withdrawal phenomena have been attributed to psychosis arising from D2 supersensitivity, which is unlikely since it has minimal action on D2 receptors. The time course and clinical features of this phenomenon suggest that cholinergic overdrive and gamma-aminobutyric acid (GABA) supersensitivity occurs after withdrawal, since it is strongly anticholinergic and has a GABAergic action. Recently, a number of patients showed marked decompensation when they were switched from clozapine to risperidone, especially when they were rapidly tapered off clozapine. This was probably more due to withdrawal effects than the primary psychosis or a lack of efficacy of risperidone. A slow withdrawal schedule would facilitate homeostatic mechanisms; anticholinergics would be useful in clozapine withdrawal. This area has not received any attention from researchers, nor are there any guidelines for clinicians. This will be particularly important with the widespread use of atypical agents in the future.

Antipsychotic Agents↗
PubMed1996

Problems and progress in the diagnosis and treatment of polydipsia and hyponatremia.

Fluid-electrolyte balance is regulated within a narrow range and disturbances in this system are unusual in animals and humans. Studies from the preneuroleptic era to date suggest that up to 25 percent of patients with schizophrenia have polydipsia, suggesting that it is related to the pathophysiology of the psychoses. Polydipsia and the related phenomenon of hyponatremia cause considerable mortality and morbidity. Prevalence studies are limited by imprecise measures available at present. The treatment was limiting water intake when patients reached critical levels of water retention, which however did not improve polydipsia. Recent case reports and open studies have shown that clozapine improves both polydipsia and water retention. The response occurs at low doses and is not related to improvement in psychosis. This may not be applicable to all patients and better understanding of the pathophysiology of polydipsia-hyponatremia would lead to more empirically derived treatments.

Behavior Therapy↗