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Biomedical subjects

G P Findlay

Publications and source records attributed to G P Findlay.

At least 19 recordsLinked to original sources
PubMed2001

Tracheal gas insufflation apparatus. Performance of a novel phase-specific device.

Tracheal gas insufflation is a technique in which gas is injected intratracheally during positive pressure ventilation. The fresh gas rinses expired gas from the tracheal tube and anatomical dead space, aiding carbon dioxide elimination. This reduces ventilatory volume and pressure, helping to reduce ventilator-induced lung damage. Complications of tracheal gas insufflation include interference with ventilator function, tracheal damage and barotrauma. Expiratory washout is a variation of tracheal gas insufflation. We designed and constructed an original expiratory washout system and evaluated its safety and performance in lung and animal models. We found that expiratory limb and tracheal tube occlusion tests caused the device to disable itself at acceptable intratracheal pressures. We also demonstrated up to 31% reduction in tidal volume compared with conventional ventilation, supporting the possibility of using this device clinically to lessen volutrauma. We concluded that aspects of this design might alleviate many of the safety concerns of using tracheal gas insufflation.

Animals↗
PubMed2000

The diagnosis of ventilator-associated pneumonia using non-bronchoscopic, non-directed lung lavages.

OBJECTIVES: (1)To assess the diagnostic utility of quantitative cultures of non-bronchoscopic lung lavage (NBL) in ventilator-associated pneumonia and evaluate the role of the Bacterial Index; (2) To assess the predictive value of NBL surveillance quantitative cultures in ventilated patients; (3) To evaluate the Clinical Pulmonary Infection Score (CPIS) system in ventilated patients. DESIGN: A prospective comparison of NBL with bronchoscopic bronchoalveolar lavage and protected specimen brush. SETTING: Three intensive care units in academic tertiary care centres. PATIENTS: 145 adults ventilated for 72 h, with and without clinical signs of pneumonia. INTERVENTIONS: Sampling of lower airway secretions by NBL, bronchoalveolar lavage and protected specimen brush. MAIN OUTCOME MEASURES: Diagnostic reliability of quantitative cultures, Bacterial Index and CPIS. RESULTS: 34 episodes of clinical ventilator-associated pneumonia were documented in 32 patients. 9 episodes were confirmed by concordant blood/pleural culture or post-mortem lung examination. Qualitative concordance of the predominant pathogen between sequential NBL: bronchoalveolar lavage and protected specimen brush was 83 %. Sensitivity and specificity of non-directed bronchial lavage at a threshold of 10(4) CFU/ml were 68 % and 70 % respectively (p = 0. 003) and were comparable with the bronchoscopic methods. However, the low positive predictive value of NBL indicates that quantitation in the absence of clinical signs is unlikely to be useful. Bacterial Index did not improve discriminatory power of quantitation compared with bacterial load of predominant organism. Mean CPIS for confirmed pneumonia cases was 8.4 +/- 1.01, significantly higher than for non-pneumonia observations (p = < 0.0001). CONCLUSION: NBL is a simple, safe, cheap, readily-available method of diagnosing ventilator-associated pneumonia with comparable diagnostic accuracy to bronchoscopic techniques. Quantitation of respiratory tract cultures can exclude pneumonia in patients with equivocal clinical signs. The diagnostic threshold should vary depending on the length of ventilation, likelihood of pneumonia and antibiotic administration. The Bacterial Index is a flawed mathematical device that has no contributory role in pneumonia diagnosis. The CPIS has some diagnostic role in selected cohorts of ventilated patients.

APACHE↗
PubMed1998

The recognition of critical incidents: quantification of monitor effectiveness.

We have conducted a prospective analysis of all reported critical incidents which occurred during the period from admission to the anaesthetic room until discharge from the operating theatre complex over a 1-year. The aim was to identify which monitors were most effective for initial recognition of those incidents. All patients were monitored in accordance with the recommendations of the procedures gave rise to 338 recorded critical incidents, of which 27 were deemed to have caused, or been likely to cause, patient harm. We have shown that a combination of arterial blood pressure measurement (noninvasive), ECG, pulse oximetry and clinical observation detected 90% of all reported critical incidents, and all the incidents causing patient harm. We have also shown that blood pressure monitoring by itself, and combination with ECG and pulse oximetry, detected proportionately more critical incidents resulting in patient harm (incidents resulting in harm remaining incidents, for each monitor) than clinical observation alone (p < 0.05) and all other remaining forms of monitoring together (p < 0.01).

Blood Pressure Determination↗
PubMed1997

Aluminum activates an anion channel in the apical cells of wheat roots.

We describe an anion channel in the plasmalemma of protoplasts isolated from wheat (Triticum aestivum L.) roots that is activated by aluminum (Al3+). In the whole-cell configuration, addition of 20-50 microM AlCl3 to the external solution depolarized the membrane and activated an inward current that could remain active for more than 60 min. The activation by Al3+ was rapid in 20% of protoplasts examined, whereas in another 30% a delay of more than 10 min occurred after Al3+ was added. Once the current was activated, changing the external Cl- concentration shifted the membrane reversal potential with ECl, showing that the channel is more selective for anions than cations (Ca2+, K+, tetraethylammonium+). The channel could be activated by Al3+, but not by La3+, and was observed in protoplasts isolated from the root apex but not in protoplasts isolated from mature root tissue. The anion channel antagonist niflumate inhibited the current in whole cell measurements by 83% at 100 microM. Outside-out patch recordings revealed a multistate channel with single-channel conductances of between 27 and 66 pS.

Journal Article↗
PubMed1996

Rocuronium pretreatment reduces suxamethonium-induced myalgia: comparison with vecuronium.

We have studied, in 150 patients undergoing elective oral surgery, the effectiveness and sequelae of pretreatment with rocuronium for reducing myalgia after suxamethonium. Patients were allocated randomly to one of three groups: anaesthesia was induced with propofol and fentanyl, and group V received vecuronium 1 mg, group R rocuronium 6 mg and group P placebo pretreatment. Suxamethonium 1.5 mg kg-1 was given 60 s after the pretreatment agent. All patients received ketorolac 10 mg i.v. and morphine 10 mg i.m. for analgesia. The incidence of postoperative myalgia on day 1 after rocuronium (20%) was significantly less than after vecuronium (42%) (P < 0.05) or placebo (70%) (P < 0.01). By day 4 the incidence of myalgia was 28.6% in the rocuronium group, 46.3% in the vecuronium group and 95% in the placebo group. Intubating conditions were not affected adversely by any pretreatment regimen.

Adolescent↗
PubMed1995

A prospective analysis of critical incidents attributable to anaesthesia.

The purpose of the study was an accurate and comprehensive prospective analysis of all untoward anaesthetic events and their sequelae, within a general hospital over a period of 1 year. We identified five system sets into which each of these critical incidents could be categorised. We also recorded data pertaining to the severity of the disturbance or event, the monitor that first identified the problem and the affect, if any, of the incident upon the patient. We found a critical incident rate of 6.68%, or one in 15 anaesthetic procedures performed. By far the majority of incidents were rapidly detected and effectively managed, with a morbidity rate of only 0.53%. The application of minimum monitoring standards was strongly reinforced. The presence of an anaesthetist throughout the period of the whole anaesthetic was shown to be the most effective component of these standards. The audit identified a trend for junior anaesthetists in particular to have a higher incidence of problems with the airway and circulation and for these to be associated with increased morbidity. This prompted revised supervision and training strategies for our junior anaesthetists.

Anesthesia↗