Biomedical subjects

Linda Denehy

Publications and source records attributed to Linda Denehy.

7 recordsLinked to original sources

PubMed2007

Efficacy of a heated passover humidifier during noninvasive ventilation: a bench study.

BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. OBJECTIVES: To examine the effects of mechanical ventilation parameters on relative humidity and absolute humidity during NPPV, and to evaluate the effect of a heated passover humidifier on relative humidity, absolute humidity, and ventilator performance during NPPV. METHODS: We performed a bench study to assess the effects of inspiratory positive airway pressure (IPAP) of 10 cm H(2)O, 15 cm H(2)O, and 20 cm H(2)O, respiratory rates of 12 breaths/min and 24 breaths/min, and inspiratory-expiratory ratios of 1:2 and 1:3 on relative and absolute humidity. The measurements were obtained on room air and with a heated humidifier at medium and maximum heater settings. RESULTS: Without humidification, the relative humidity in the NPPV circuit (range 16.3-26.5%) was substantially lower than the ambient relative humidity (27.6-31.5%) at all ventilatory settings. Increasing the IPAP decreased the relative humidity (Spearman's rho = 0.67, p < 0.001). Changing the respiratory rate or inspiratory-expiratory ratio had no significant effect. Both relative and absolute humidity increased with humidification, and the air was fully saturated at the maximum heater setting. Delivered IPAP was reduced by 0.5-1 cm H(2)O during humidification. CONCLUSIONS: NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.

Benchmarking↗

PubMed2004

Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated.

The purpose of this prospective randomised cross-over study was to measure peak expiratory flow rates during manual hyperinflation and to determine if the addition of a head-down tilt to physiotherapy treatment increased sputum production in patients who are intubated and ventilated. Twenty patients who were intubated, ventilated and haemodynamically stable were randomised to a sequence of physiotherapy treatment in a flat side-lying or a head-down tilt position. Peak expiratory flow rates were measured for each breath during manual hyperinflation using a Vitalograph peak flow meter. Sputum wet weight was collected for each treatment position and static pulmonary compliance was measured before and immediately following physiotherapy treatment. There was a significant increase in peak expiratory flow (p < 0.001) and sputum production (p = 0.008) in the head-down tilt position. The mean difference and 95% confidence intervals for expiratory flow were 0.17 (0.15 to 0.19) l/sec and for the wet weight of sputum 1.97 (0.84 to 3.10) g. The peak expiratory flow rate was sufficient to produce annular flow in both flat side-lying (1.97 +/- 0.09) l/sec and in the head-down tilt position (2.14 +/- 0.08) l/sec. Static pulmonary compliance improved significantly following physiotherapy treatment (p = 0.003). The mean difference and 95% confidence intervals pre- and post-treatment for static pulmonary compliance were 5.18 (2.14 to 8.22) ml/cmH(2)O. The results suggest that addition of a head-down tilt to physiotherapy treatment, including manual hyperinflation, in patients who are intubated and ventilated, increases sputum production and improves peak expiratory flow.

Adult↗

PubMed2003

The effect of physiotherapy treatment on oxygen consumption and haemodynamics in patients who are critically ill.

The purpose of this study was to determine metabolic and haemodynamic changes with and without physiotherapy treatment in haemodynamically stable, intubated and ventilated patients. This was a prospective, randomised cross-over study. Ten intubated, ventilated and haemodynamically stable patients underwent a 20 min physiotherapy treatment and a 20 min period of undisturbed side lying. Mean oxygen consumption (VO2mean) was measured on a minute-to-minute basis by indirect calorimetry. Mean arterial pressure (MAP) was recorded minutely from the indwelling arterial line and cardiac index (CI) was calculated from the indwelling pulmonary artery catheter. Time to recovery to within 5% of resting VO2 was also recorded. The results showed no significant increase in VO2mean with either positioning the patient in side lying or physiotherapy treatment (p = 0.17). Time to recovery to within 5% of baseline VO2 occurred within seven minutes for all patients and there was no significant difference between either physiotherapy treatment or positioning in side lying (p = 0.63). There were no significant differences in CI (p = 0.44) or MAP (p = 0.95) during physiotherapy treatment compared with undisturbed side lying. It is concluded that physiotherapy treatment does not significantly alter VO2mean or MAP and CI in stable intubated and ventilated patients.

Aged↗

PubMed2003

Does removal of deep breathing exercises from a physiotherapy program including pre-operative education and early mobilisation after cardiac surgery alter patient outcomes?

The aim of this study was to establish whether removal of breathing exercises from a regimen including early mobilisation changes the incidence of post-operative pulmonary complications for patients after cardiac surgery. Two hundred and thirty patients undergoing open heart surgery at Monash Medical Centre, Melbourne, were enrolled in this randomised controlled trial. All patients received physiotherapy treatment pre-operatively and post-operatively for three days. Patients were mobilised as soon as possible after surgery. Breathing group (control) patients performed a set routine of deep breathing exercises at each physiotherapy visit while those in the intervention group did not perform this routine. Other than the breathing exercises, patient management was similar between groups in terms of assessment, positioning and mobility. The incidence of postoperative pulmonary complications, post-operative length of stay, oxyhaemoglobin saturation and pulmonary function were measured pre-operatively and post-operatively. Intention-to-treat analysis was performed for post-operative pulmonary complications and length of stay. Other data were analysed using t-tests, chi square and repeated measures analysis of variance. There were no significant differences between the groups in the primary dependent variables. It is concluded that removal of breathing exercises from the routine physiotherapy management of open heart surgery patients does not significantly alter patient outcome.

Breathing Exercises↗

PubMed2002

Can early extubation and intensive physiotherapy decrease length of stay of acute quadriplegic patients in intensive care? A retrospective case control study.

BACKGROUND AND PURPOSE: Respiratory complications remain a major cause of morbidity and mortality in the acute quadriplegic patient population. The literature has suggested that early insertion of a tracheostomy facilitated pulmonary management and an earlier discharge from the intensive care unit (ICU). Recently, a change in practice has meant that these patients are considered for extubation and intensive physiotherapy treatment, including an overnight on-call service, rather than tracheostomy. The aim of the present retrospective, case-controlled study was to determine if either practice resulted in a difference in length of stay in intensive care and if an on-call physiotherapy service for these patients was cost effective. METHOD: A case control design was used. Between April 1997 and November 1999, seven patients who did not require a tracheostomy were identified; case control subjects were matched for severity with seven patients who did receive a tracheostomy. Length of stay in intensive care and on the acute ward, days from injury to fixation and the overall number of respiratory physiotherapy and night physiotherapy treatments were recorded. RESULTS: Five of the seven patients in the non-tracheostomy group received on-call overnight physiotherapy treatment, with an average of five sessions over a total of three nights. This group's length of stay in an ICU was significantly less than patients who were tracheostomized (p = 0.02). The overall number of physiotherapy treatments between the two groups was not significantly different. CONCLUSIONS: The results of this study suggest that if extubation and intensive physiotherapy is undertaken for suitable patients, the length of stay in intensive care can be significantly reduced. This represents a considerable cost saving for ICUs and more than covers the added cost of providing an after hours on-call physiotherapy treatment service. A prospective evaluation is required to confirm these findings.

Adolescent↗

PubMed2002

A comparison of the effects of manual and ventilator hyperinflation on static lung compliance and sputum production in intubated and ventilated intensive care patients.

BACKGROUND AND PURPOSE: Lung hyperinflation is a technique used by physiotherapists to mobilize and remove excess bronchial secretions, reinflate areas of pulmonary collapse and improve oxygenation. Hyperinflation may be delivered by the ventilator or manually, by use of a manual resuscitation circuit, depending upon the respiratory and cardiovascular status of the patient. The effects of manual hyperinflation, with respect to excess bronchial secretions and static lung compliance, have been well-established. There is, however, only limited evidence as to the efficacy of ventilator hyperinflation as a physiotherapy treatment technique. The purpose of the present study was to compare the effects of manual hyperinflation and ventilator hyperinflation on static pulmonary compliance and sputum clearance in stable intubated and ventilated patients. METHOD: Twenty patients who met the inclusion criteria were studied. This was a double crossover study where all patients were randomly allocated to one of two treatment sequences over two days. The first sequence involved manual hyperinflation followed two hours later by ventilator hyperinflation and the order was reversed on the second day. In the second sequence, ventilator hyperinflation preceded manual hyperinflation. The variables of static pulmonary compliance and sputum wet weight were analysed by use of an analysis of variance (ANOVA) for repeated measures. Statistical significance was set at p < 0.05. RESULTS: There was no significant difference in sputum wet weight production between either technique or on either day of treatment. Static pulmonary compliance improved with both hyperinflation techniques (p < 0.05). CONCLUSIONS: Hyperinflation as part of a physiotherapy treatment can be performed with equal benefit using either a manual resuscitation circuit or a ventilator. Both methods of hyperinflation improve static pulmonary compliance and clear similar volumes of pulmonary secretions.

Adolescent↗

PubMed1999

A survey of manual hyperinflation in Australian hospitals.

A telephone survey was conducted to examine the use of manual hyperinflation (MHI) by physiotherapists in intensive care units (ICUs) in 32 Australian teaching hospitals. A 100 per cent response rate was obtained from senior ICU physiotherapists. Results showed that 91 per cent of respondents used manual hyperinflation as a physiotherapy treatment technique. There was strong agreement on the components of the technique, preferred treatment position, contraindications and perceived benefits but considerable variation in duration of treatment, number of breaths per set and circuits used. Fewer than 55 per cent stated that a maximum airways pressure of 40 cm H2O or less was used with MHI and only 31 per cent monitored airways pressure. These results are compared with previously published surveys.

Journal Article↗