Proportional assist ventilation versus pressure support ventilation in weaning ventilation: a pilot randomised controlled trial

OBJECTIVE

Proportional assist ventilation with load-adjustable gain factors (PAV+) is a mode of ventilation that provides assistance in proportion to patient effort. This may have physiological and clinical advantages when compared with pressure support ventilation (PSV). Our objective was to compare these two modes in patients being weaned from mechanical ventilation.

DESIGN

Prospective randomised controlled trial comparing PSV with PAV+.

SETTING

University-affiliated, tertiary referral intensive care unit (ICU).

PARTICIPANTS

Mechanically ventilated patients on a controlled mode of ventilation for at least 24 hours, who were anticipated to be spontaneously ventilated for at least 48 hours after randomisation.

INTERVENTIONS

Nil.

MAIN OUTCOME MEASURES

The primary outcome was time to successful liberation from the ventilator after the commencement of a spontaneous mode of ventilation. Secondary outcomes were requirement of rescue (mandatory) ventilation, requirement of sedative drugs, requirement for tracheostomy, re-intubation within 48 hours of extubation, ICU length of stay (LOS), hospital LOS, and ICU and hospital mortality.

RESULTS

50 patients were randomised to either PSV (n = 25) or PAV+ (n = 25). There was no significant difference between the PAV+ and PSV groups in time to successful weaning (84.3 v 135.9 hours, respectively; P = 0.536). Four patients randomised to PAV+ were crossed over to PSV during weaning. There was no significant difference between groups for rescue ventilation, reintubation within 48 hours, tracheostomy, sedatives and analgesics prescribed, and ICU and hospital LOS. ICU mortality was higher in the PSV group (25% v 4 %; P = 0.002).

CONCLUSIONS

Both modes of ventilation were comparable in time to liberation from the ventilator.

Low-flow veno-venous extracorporeal carbon dioxide removal in the management of severe status asthmatics: a case report

Status asthmaticus is a life-threatening condition that requires intensive care management. Most of these patients have severe hypercapnic acidosis that requires lung protective mechanical ventilation. A small proportion of these patients do not respond to conventional lung protective mechanical ventilation or pharmacotherapy. Such patients have an increased mortality and morbidity. Successful use of extracorporeal membrane oxygenation (ECMO) is reported in such patients. However, the use of ECMO is invasive with its associated morbidity and is limited to specialised centres. In this report, we report the use of a novel, minimally invasive, low-flow extracorporeal carbon dioxide removal device in management of severe hypercapnic acidosis in a patient with life threatening status asthmaticus.

Imatinib for bleomycin induced pulmonary toxicity: a case report and evidence-base review

The evidence supporting therapy with imatinib for bleomycin‐induced pneumonitis (BIP) is equivocal. Further experience is needed to establish its role in BIP management. While it may be considered in the management of BIP, it is important to be mindful of the adverse effects including thrombocytopenia and gastrointestinal bleeding.

Management of severe hypercapnia post cardiac arrest with extracorporeal carbon dioxide removal

Normocapnia is recommended in intensive care management of patients after out-of-hospital cardiac arrest. While normocapnia is usually achievable, it may be therapeutically challenging, particularly in patients with airflow obstruction. Conventional mechanical ventilation may not be adequate to provide optimal ventilation in such patients. One of the recent advances in critical care management of hypercapnia is the advent of newer, low-flow extracorporeal carbon dioxide clearance devices. These are simpler and less invasive than conventional extracorporeal devices. We report the first case of using a novel, extracorporeal carbon dioxide removal device in Australia on a patient with out-of-hospital cardiac arrest where mechanical ventilation failed to achieve normocapnia.

Hypothermia predicts mortality in critically ill elderly patients with sepsis

BACKGROUND

Advanced age is one of the factors that increase mortality in intensive care. Sepsis and multi-organ failure are likely to further increase mortality in elderly patients.We compared the characteristics and outcomes of septic elderly patients (> 65 years) with younger patients (≤ 65 years) and identified factors during the first 24 hours of presentation that could predict mortality in elderly patients.

METHODS

This study was conducted in a Level III intensive care unit with a case mix of medical and surgical patients excluding cardiac and neurosurgical patients.We performed a retrospective review of all septic patients admitted to our ICU between July 2004 and May 2007. In addition to demographics and co-morbidities, physiological and laboratory variables were analysed to identify early predictors of mortality in elderly patients with sepsis.

RESULTS

Of 175 patients admitted with sepsis, 108 were older than 65 years. Elderly patients differed from younger patients with regard to sex, temperature (37.2°C VS 37.8°C p < 0.01), heart rate, systolic blood pressure, pH, HCO3, potassium, urea, creatinine, APACHE III and SAPS II. The ICU and hospital mortality was significantly higher in elderly patients (10.6% Vs 23.14% (p = 0.04) and 19.4 Vs 35.1 (p = 0.02) respectively). Elderly patients who died in hospital had a significant difference in pH, HCO3, mean blood pressure, potassium, albumin, organs failed, lactate, APACHE III and SAPS II compared to the elderly patients who survived while the mean age and co-morbidities were comparable. Logistic regression analysis identified temperature (OR [per degree centigrade decrease] 0.51; 95% CI 0.306- 0.854; p = 0.010) and SAPS II (OR [per point increase]: 1.12; 95% CI 1.016-1.235; p = 0.02) during the first 24 hours of admission to independently predict increased hospital mortality in elderly patients.

CONCLUSIONS

The mortality in elderly patients with sepsis is higher than the younger patients. Temperature (hypothermia) and SAPS II scores during the first 24 hours of presentation independently predict hospital mortality.

An Investigation into VOC Emissions from Polyurethane Flexible Foam Mattresses

Emissions of volatile species from flexible polyurethane foam mattresses were investigated by using large scale chamber tests designed to replicate the product use as mattress cores. Various trace impurities were identified and their concentrations were measured for input into a human health and toxicity risk assessment, which has concluded that none was injurious to health. The raw materials used to make the foam were analysed to identify the source of emanations and routes to their reduction or elimination. Several analytical artefacts were identified, and some recommendations made for their avoidance. Detailed product knowledge was essential to the reliable interpretation of analytical data. A quantitative risk assessment was carried out on each of the volatiles. No evidence of any human health risk was identified from the ‘worst-case’ exposure model employed

The Irukandji syndrome. A devastating syndrome caused by a north Australian jellyfish

BACKGROUND

The Irukandji syndrome is a group of delayed (10-40 mins, mean 30 mins) severe systemic symptoms occurring after an initial mild skin sting by small carybdeid (box) jellyfish including Carukia barnesi, known colloquially as the 'Irukandji'. Although the syndrome is well known in tropical Australian waters, the 1998-1999 season in north Queensland was notable for the unusually high number of victims with severe toxic heart failure who needed admission to intensive care facilities for more complex investigations and treatment. There have also been other severe and unusual symptoms reported this year, which leads to the conclusion that there may be more than one species of jellyfish causing the Irukandji syndrome, or a seasonal variation in the symptoms and/or severity of symptoms caused by Carukia spp.

OBJECTIVE

This article describes the updated current state of information on the ecology of jellyfish causing the Irukandji syndrome, introduces the new symptoms, and discusses some treatment regimens that may be effective. Problems associated with inappropriate treatment are also discussed.

DISCUSSION

To date there have been no reported deaths from Irukandji envenomation but there have been a number of patients who were probably only saved by high quality intensive care treatment. Research into the cause and treatment of this potentially devastating syndrome is hampered by lack of funding, although there are large costs to the taxpayers for retrieval and medical treatment of victims. These costs are analysed and presented.

A presumptive case of fatal Murray Valley encephalitis acquired in Alice Springs

A presumptive case of Murray Valley Encephalitis (MVE) acquired in Alice Springs in March 1997 is reported. The patient subsequently died in Mackay. The diagnosis of Murray Valley Encephalitis was supported by the detection of flavivirus IgM in cerebrospinal fluid. Low titres of IgM specific to Murray Valley Encephalitis and Alfuy were detected in a single serum sample. The patient's travel movements indicate that his infection was acquired in the Alice Springs vicinity. This conclusion was further supported by the detection of Murray Valley Encephalitis activity in sentinel animals in the area and by the presence of large numbers of the principal mosquito vector of Murray Valley Encephalitis in the Northern Territory.