Ventilation and weaning practices in Australia and New Zealand.

Using a one-day prospective point prevalence design, this study aimed to characterise the current practice of mechanical ventilation and weaning in Australian and New Zealand intensive care units. During 2005, a bi-national one-day survey of 55 intensive care units found the point-prevalence of mechanical ventilation to be 284/491(58%). Common modes used were synchronised intermittent mandatory ventilation with pressure support, pressure support ventilation (each 116/284, 41%) and pressure-control modes (48/284, 17%). Relative to volume-control modes, pressure-control was more frequently used for patients with respiratory disease (odds ratio 4.7, 95% confidence interval 2.4 to 9.2, P <0.001) or greater severity of illness (odds ratio 1.7, 95% confidence interval 1.1 to 2.6, P = 0.01, per five-point increment in the maximum sequential organ failure score). Excluding cardiothoracic surgery patients, the Kaplan-Meier estimated median total ventilation duration was 1.9 days (interquartile range 0.8 to 6.8 days). Apart from 24/255 (9.4%) patients who received only pressure support ventilation, weaning methods (attempted in 255 patients, 29 prior deaths) included: change to pressure support ventilation (186/255, 73%), T-piece (31/255, 12%) or other methods (14/255, 5.5%). The point prevalence of mechanical ventilation was greater than comparable international studies. Australian and New Zealand intensive care unit ventilatory practices are similar, but differ substantially from published international survey results, due to a near absence of assist/control, prominent use of pressure-control modes and a preference forpressure support ventilation weaning as opposed to T-piece.

Update in computer-driven weaning from mechanical ventilation.

Weaning from mechanical ventilation is a complex process requiring assessment and interpretation of both objective and subjective clinical parameters. For many years, automated computerised systems for various medical processes, including respiratory management, have been proposed to optimise decision-making and reduce variation amongst clinicians. SmartCare/PS, available since 2003 as a software application for the EvitaXL ventilator (Dräger Medical AG & Co. KG, Lübeck, Germany), is one of the first such ventilator systems to be made commercially available. SmartCare/PS can be described as a knowledge-based weaning system, which adjusts pressure support based on measurement of the patient's respiratory status, specifically the spontaneous respiratory rate, tidal volume and end-tidal carbon dioxide with the aim of optimising the weaning process. The primary proposed advantage of this system is an ability to provide management of ventilatory weaning through continuous physiological monitoring and real-time interventions. The relatively small number of available clinical studies indicate the system is able to deliver appropriate ventilation during pressure support weaning from both short-term and prolonged ventilation. Of potential clinical note, a recent study suggested that use of SmartCare/PS might be associated with useful reductions in the duration of weaning compared to existing clinical practice using weaning protocols. One recently published randomised trial supports this conclusion. However, given the known large variation in international critical care ventilatory practices further randomised trials are desirable.

The microbiology and outcome of sepsis in Victoria, Australia.

We analysed data from 33741 patients with ICD-10-AM-defined sepsis from an Australian hospital morbidity dataset to investigate the relationships between specific types of organisms, potential risk factors for infection, organ dysfunction, ICU utilization and hospital mortality. A total of 24% of patients received some of their care in an intensive care unit, and the overall hospital mortality rate was 18%. Gram-positive bacteria were isolated in 27% of cases and Gram-negative bacteria in 20%. Sepsis due to Staphylococcus aureus was associated with vascular and joint devices whereas Pseudomonas aeruginosa and Gram-negative rods were more common with genitourinary devices and lymphoproliferative disease. Sepsis-associated organ dysfunction most commonly involved the respiratory system, followed by the renal and circulatory systems. These patterns may provide useful clues to the pathogenesis and therapy of this often fatal syndrome which is a major ongoing problem for hospitalized patients.

Blood usage in an Australian intensive care unit: have we met best practice goals?

The transfusion of blood products, especially red cell concentrates, in critically ill patients is controversial and benefits of red cell concentrate transfusion in these patients have not been clearly demonstrated. We performed a prospective observational study to compare best evidence to actual practice of red cell concentrate and other blood product administration in an intensive care unit (ICU) in a university-associated tertiary hospital. All primary admissions during a 28-day period were included in the study and data collected included transfusion of red cells and blood products, patient demographics and ICU and hospital outcome. One hundred and seventy-five admissions were studied; 44% followed cardiac surgery. Forty-one patients (23%) received red cell concentrates in ICU, with 120 units transfused in 61 separate episodes. Other blood product usage was minimal. One third (20/61) of red cell concentrate transfusion episodes were of a single unit. The mean (+/- SD) pre-transfusion haemoglobin was 7.9 +/- 1.1 g/dl. Despite transfusion, such patients left ICU with a lower haemoglobin concentration compared with untransfused ICU patients (9.5 +/- 1.0 versus 10.5 +/- 2.1 g/dl; P < 0.001). Cardiac surgical patients received similar red cell transfusion to general ICU patients. Univariate analysis showed no significant difference in mortality between patients who did or did not receive red cell concentrate transfusion (P = 0.17). However, red cell concentrate transfusion was associated with a reduced adjusted mortality both in ICU (OR 0.13, 95% CI 0.02-0.73) and in hospital at 28 days (OR 0.10, 95% CI 0.02-0.58). The low red cell concentrate and blood product usage in our ICU were consistent with restrictive transfusion practice and selective red cell concentrate transfusion was associated with reduced mortality.

Helicobacter pylori infection in the Australian community: current prevalence and lack of association with ABO blood groups.

AIMS: To assess the current prevalence of Helicobacter pylori infection in an Australian urban population sample and to relate this to age, gender and ABO and Rhesus blood groups. METHODS: We performed a prospective epidemiological survey of H. pylori serological status in 500 consecutive voluntary blood donors who presented for the purpose of blood donation at the central -Melbourne branch of the Australian Red Cross Blood Service, Victoria, Australia, and gave a Melbourne suburban home address. RESULTS: The overall prevalence of specific anti-H. pylori IgG antibodies in this cohort was 32% (95% confidence interval = 28-36%) and H. pylori sero-positivity increased with age. The rate of H. pylori infection was not significantly different in men and women, with anti-H. pylori IgG anti-bodies detected in 35% (97/277) of men compared with 28% (63/233) of women (P = 0.12). Similarly, H. pylori serological status was not significantly different between subjects of different ABO (P = 0.18) or Rhesus blood groups (P = 0.55). CONCLUSION: This study showed that, contrary to expectation, the updated prevalence of H. pylori seropositivity (32%) in this Melbourne sample is at least as high as that found in previous Australian studies over the past 19 years. Seropositivity increased with age, and was not related to gender, confirming the infection pattern seen in other developed nations. Despite epidemiological evidence of increased peptic ulcer disease in ABO blood group O subjects, and recent evidence that H. pylori adhesion to gastric epithelial cells is mediated by blood group epitopes, no significant association between blood groups and H. pylori serological status was detected.

The influence of a blood conserving device on anaemia in intensive care patients.

The contribution of iatrogenic blood loss through diagnostic testing to the anaemia of critical illness remains controversial. We measured the effect of an arterial line blood conservation device upon blood loss and anaemia in adult intensive care patients. This randomized controlled trial of 160 patients in a major Intensive Care Unit (ICU) compared a blood conservation device (Venous Arterial Blood Management Protection Plus, VAMP Plus system, Baxter Healthcare) (VAMP group) to a standard arterial pressure line set attached to an arterial catheter (control group). The primary outcome measured was the change in haemoglobin concentration (Hb) during each patient's ICU admission and the volume of blood lost through diagnostic testing in ICU was also recorded. Both groups of 80 patients were matched for age, gender, severity of illness (APACHE II), baseline Hb on entry and ICU length of stay. Both groups had a similar (median [range]) change in Hb during ICU admission (VAMP-7 [-84 to +21] g/l; Control -4 [-67 to +40] g/l; P = 0.33). The VAMP patients lost significantly less blood for diagnostic testing while in ICU (VAMP 63 [0 to 787] ml; Control 133 [7 to 1227] ml; P = 0.001). We conclude that the VAMP Plus system significantly reduced iatrogenic blood loss in critically ill patients, but this reduction did not affect the fall in Hb that accompanies critical illness.

Chest physiotherapy for the prevention of ventilator-associated pneumonia.

OBJECTIVE: Pneumonia is an important complication in patients who are intubated and mechanically ventilated, when it is commonly referred to as ventilator-associated pneumonia (VAP). Since VAP may be contributed to by impaired sputum clearance, we studied whether chest physiotherapy designed to enhance sputum clearance decreases the occurrence of VAP. DESIGN: Prospective controlled systematic allocation trial. SETTING: Tertiary teaching hospital ICU. PATIENTS AND PARTICIPANTS: Sixty adult patients intubated and mechanically ventilated for at least 48 h. INTERVENTIONS: Chest physiotherapy (intervention group) or sham physiotherapy (control group). MEASUREMENTS AND RESULTS: Control and intervention groups were well matched for age, sex, and admission PaO(2)/FiO(2) ratio, APACHE II score, and Glasgow Coma Score. There were no differences in the duration of mechanical ventilation, length of stay in ICU or mortality. VAP was assessed daily by combined clinical assessment and the clinical pulmonary infection score (CPIS). VAP occurred in 39% (14/36) of the control group and 8% (2/24) of the intervention group (OR = 0.14, 95% CI 0.03 to 0.56, P = 0.02). After adjustment was made by logistic regression for other important variables (APACHE II score, duration of mechanical ventilation, presence of tracheostomy, and GCS score), chest physiotherapy was independently associated with a reduced occurrence of VAP (adjusted OR = 0.16, 95% CI 0.03 to 0.94, P = 0.02). CONCLUSIONS: In this small trial, chest physiotherapy in ventilated patients was independently associated with a reduction in VAP. This suggested benefit of physiotherapy in prevention of VAP requires confirmation with a larger randomised controlled trial.

Prospective randomised open-label comparison of danaparoid with dextran 70 in the treatment of heparin-induced thrombocytopaenia with thrombosis: a clinical outcome study.

AIM: To compare clinical outcomes in a randomised comparison of treatment with danaparoid sodium (a heparinoid), or dextran 70, for heparin-induced thrombocytopaenia (HIT) plus thrombosis. METHODS: Forty-two patients with recent thrombosis and a clinical diagnosis of probable HIT who presented at ten Australian hospitals during a study period of six and one half years were randomly assigned to open-label treatment with intravenous danaparoid or dextran 70, each combined with oral warfarin. Thirty-four patients (83%) had a positive platelet aggregation or 14C-serotonin release test for HIT antibody. Twenty-five received danaparoid as a bolus injection of 2400 anti-Xa units followed by 400 units per hour for 2 h, 300 units per hour for 2 h, and then 200 units per hour for five days. Seventeen received 1000 mL dextran 70 on day one and then 500 mL on days 2-5. Patients were reviewed daily for clinical evidence of thrombus progression or resolution, fresh thrombosis or embolism, bleeding or other complications. The primary trial endpoint was the proportion of thromboembolic events with complete clinical resolution by the time of discharge from hospital. RESULTS: With danaparoid, there was complete clinical recovery from 56% of thromboembolic events compared to 14% after dextran 70 (Odds Ratio 10.53, 95% Confidence Interval 1.6-71.4; p = 0.02). Clinical recovery with danaparoid was complete or partial in 86% of thromboembolic events compared with 53% after dextran 70 (Odds Ratio 4.55, 95% Confidence Interval 1.2-16.7; p = 0.03). Overall clinical effectiveness of danaparoid was rated as high or moderate in 88% of patients compared with 47% for dextran 70 (p = 0.01). One patient given danaparoid died of thrombosis compared with three patients given dextran 70. The platelet count returned to normal after a mean of 6.7 days with danaparoid and 7.3 days with dextran 70. There was no major bleeding with either treatment. CONCLUSION: danaparoid plus warfarin treatment for HIT with thrombosis is effective, safe, and superior to dextran 70 plus warfarin.

Plasma granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor levels in critical illness including sepsis and septic shock: relation to disease severity, multiple organ dysfunction, and mortality.

OBJECTIVE: To define the circulating levels of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) during critical illness and to determine their relationship to the severity of illness as measured by the Acute Physiology and Chronic Health Evaluation (APACHE) II score, the development of multiple organ dysfunction, or mortality. DESIGN: Prospective cohort study. SETTING: University hospital intensive care unit. PATIENTS: A total of 82 critically ill adult patients in four clinically defined groups, namely septic shock (n = 29), sepsis without shock (n = 17), shock without sepsis (n = 22), and nonseptic, nonshock controls (n = 14). INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: During day 1 of septic shock, peak plasma levels of G-CSF, interleukin (IL)-6, and leukemia inhibitory factor (LIF), but not GM-CSF, were greater than in sepsis or shock alone (p < .001), and were correlated among themselves (rs = 0.44-0.77; p < .02) and with the APACHE II score (rs = 0.25-0.40; p = .03 to .18). G-CSF, IL-6, and UF, and sepsis, shock, septic shock, and APACHE II scores were strongly associated with organ dysfunction or 5-day mortality by univariate analysis. However, multiple logistic regression analysis showed that only septic shock remained significantly associated with organ dysfunction and only APACHE II scores and shock with 5-day mortality. Similarly, peak G-CSF, IL-6, and LIF were poorly predictive of 30-day mortality. CONCLUSIONS: Plasma levels of G-CSF, IL-6, and LIF are greatly elevated in critical illness, including septic shock, and are correlated with one another and with the severity of illness. However, they are not independently predictive of mortality, or the development of multiple organ dysfunction. GM-CSF was rarely elevated, suggesting different roles for G-CSF and GM-CSF in human septic shock.

Smart technology improves patient-controlled analgesia: a preliminary report.

UNLABELLED: A new adaptive system has been designed to improve patient-controlled analgesia through the use of a variable bolus dose and a variable background infusion of analgesic. A novel hand set allows patients to rate their own pain on a linear scale of 1 to 10. Data derived from the hand set signals are used by an expert algorithm to repeatedly adapt the drug dosage of the bolus and of the background infusion according to both current pain intensity and the patient's response to previous dosage. To test the system, we performed a small pilot clinical study, using a randomized, double-blinded, cross-over design. The new system was alternated with a conventional system every 12 h. Use of the new system was associated with significantly lower pain scores and fewer bolus requests but more analgesic administration, though without increased adverse effects. It was very well accepted by both patients and clinical staff. IMPLICATIONS: Pain relief after surgery is often best provided by patient-controlled analgesia, which uses an IV infusion pump and a patient-activated switch. We have developed a new computer-controlled or "smart" patient-controlled analgesia that rapidly learns a patient's individual needs and provides continuously tailored pain relief.

Helicobacter pylori infection in intensive care: increased prevalence and a new nosocomial infection.

OBJECTIVE: The pathogenesis of acute gastric stress ulceration in the seriously ill is uncertain, and any role of Helicobacter pylori infection is unknown. We aimed to assess the relationship between H. pylori serological status and stress ulceration in seriously ill patients, as well as H. pylori serological status in intensive care nurses as a marker for nosocomial infection. DESIGN: Prospective epidemiologic survey. SETTING: Adult intensive care unit in a university teaching hospital. PATIENTS: One hundred patients, 100 nurses, and 500 blood donors as community controls. INTERVENTIONS: H. pylori serological status was measured in patients, staff, and controls using a rapid whole blood test. Upper gastrointestinal bleeding and risk factors for acute stress ulceration were recorded. MEASUREMENTS AND MAIN RESULTS: In seriously ill patients, H. pylori seropositivity (67%) was significantly higher than in the control group (39%) (p < .001). In patients, seropositivity was not related to age, country of birth, diagnostic category, severity of illness, or risk score for stress ulceration. There was a trend toward increased macroscopic gastric bleeding in seropositive patients. In intensive care nurses, H. pylori seropositivity (40%) was significantly higher than in age-matched controls (19%) (p < .001). Only duration of intensive care nursing was significantly associated with seropositivity (p = .02). CONCLUSIONS: The unexpectedly high H. pylori seropositivity rate in this seriously ill cohort raises the possibility that under intensive care conditions, H. pylori infection may modulate responses to illness and injury, with consequent clinical implications. Furthermore, the elevated seropositivity rate in intensive care nurses suggests that H. pylori can be nosocomially transmitted.

Pain relief using smart technology: an overview of a new patient-controlled analgesia device.

A new adaptive patient-controlled analgesia (PCA) system designed to improve PCA through the use of a variable bolus dose and a variable background infusion is outlined here. The handset allows patients to rate their pain on a scale of 1-10. Data derived from the handset signals are used by an expert algorithm to repeatedly adapt the drug dosage of the bolus and the background infusion according to both pain intensity and patient response to previous dosages. A feasibility study of the system consisted of a small number of randomized, double-blind, crossover clinical trials. The new system was alternated with a conventional system every 12 h. When the new system was active, 12-h questionnaire pain scores were significantly lower and a trend toward fewer bolus requests was found in alternating intervals. In addition, when the new system was used to commence trials, the number of bolus requests were significantly lower and there was a trend toward lower handset scores, lower questionnaire pain scores, and lower verbal pain scores over the entire trial period. The new adaptive PCA system was well accepted by both patients and clinical staff. The trials successfully established the feasibility of the new system. Further development is being carried out as a result.

The optimal dosage of ceftazidime for severe lower respiratory tract infections.

The optimal dosage of antibiotics for the treatment of patients with severe lower respiratory tract infections (LRTI) has not been determined but may be lower than is commonly administered at present. We have compared the efficacy of a low dosage of ceftazidime (1 g tds) with the more usual dosage (2 g tds) in a prospective, randomized study of the treatment of LRTI in seriously ill patients. Fifty patients on an Intensive Care Unit received one or the other regimen for 5 days; the demographic characteristics of the two groups were comparable. There was no significant difference in terms of clinical and microbiological response rates between the two regimens. Overall, clinical resolution was documented for 86% of patients, there was no change in 8% and 6% deteriorated. Microbiological eradication was achieved in 52% of patients from whom a pathogen was isolated (46% of all patients). We conclude that ceftazidime 1 g tds is effective treatment for severe LRTI in hospitalized patients.

Oxygen dissociation curve in the adult respiratory distress syndrome.

The oxygen tension for half saturation (P50) was determined for venous blood in thirteen patients with the adult respiratory distress syndrome undergoing intensive therapy. The mean value for P50 was found to be significantly lower than the value found in ten normal control subjects (22.9 mmHg and 26.7 mmHg respectively; t = 3.03, P < 0.01). The extent of reduction in P50 was not related to serum phosphate level nor was it a predictor of short-term outcome. It is unlikely that the slight left-shifted oxygen-haemoglobin dissociation curve contributes in a major way to an oxygen delivery deficiency and its cause is unexplained.

Apparent lack of synergism between heparin and dihydroergotamine in prevention of deep vein thrombosis after elective hip replacement: a randomised double-blind trial reported in conjunction with an overview of previous results.

We report the results of a double-blind, randomised trial of venous thrombosis (VT) prevention in 117 patients having elective hip replacement where low dose heparin alone (5,000 IU sodium heparin given subcutaneously [sc] 8 hourly until the seventh postoperative day) was compared with low dose heparin plus dihydroergotamine (DHE; 0.5 mg, given 8 hourly by sc injection). The trial end point consisted of VT discovered through bilateral ascending venography done routinely on the seventh postoperative day. VT developed in 34% of patients given heparin/DHE (95% confidence interval = 22% - 47%) compared with 24% in those given low dose heparin alone (95% confidence interval = 14% - 37%; p = 0.34), difference = 10% (95% confidence interval = -7% to +26%). Corresponding figures for the incidence of proximal (above-knee) thrombosis were 17% and 14% (95% confidence intervals = 8% - 29% and 6% - 25% respectively). These results are discussed in the context of a detailed overview of published evidence concerning VT prevention with heparin/DHE after hip replacement and we conclude it is unlikely that heparin/DHE is markedly superior to low dose heparin alone in this clinical setting.