Can ICU stay be predicted accurately enough for fast-tracking cardiac surgical patients?

OBJECTIVES

To improve the precision of currently available models for predicting length of stay of individual patients in the intensive care unit, to assist in directing patients into fast-track management after coronary artery bypass graft (CABG) surgery.

SETTING

ICU in an Australian teaching hospital.

DESIGN AND PARTICIPANTS

Prospectively collected data from 333 patients who underwent elective CABG surgery were analysed by univariate and multivariate regression, to develop models of increasing power through the addition of factors covering the operative and early ICU phases (1, 4 and 8 hours postoperatively) to traditional preoperative risk of patient care. The model that gave the best combination of precision and availability for clinical decision-making was then validated on a series of 117 patients who underwent CABG surgery. Overall competence of this model was assessed.

RESULTS

Addition of intraoperative factors to the first (preoperative only) model (R2 = 0.07) doubled the precision of the analysis (R2 = 0.18). Addition of factors derived from the first 4 hours of ICU management increased precision fivefold (R2 = 0.38). This model was satisfactorily validated: regression of actual versus predicted ICU stay from the validation set gave a slope of 0.85 and y intercept of 2.60 hours. The 95% confidence levels of individual predictions obtained from the development set, for an estimated ICU stay of 12 hours, spanned 43 hours.

CONCLUSIONS

Although the optimal model greatly increases precision, it is still inadequate for scheduling fasttrack patients, where wrong predictions for individuals can cause major problems in resource allocation.

Bench-to-bedside review: avoiding pitfalls in critical care meta-analysis--funnel plots, risk estimates, types of heterogeneity, baseline risk and the ecologic fallacy

Meta-analysis can be a powerful tool for demonstrating the applicability of a concept beyond the context of individual clinical trials and observational studies, including exploration of effects across different subgroups. Meta-analysis avoids Simpson's paradox, in which a consistent effect in constituent trials is reversed when results are simply pooled. Meta-analysis in critical care medicine is made more complicated, however, by the heterogeneous nature of critically ill patients and the contexts within which they are treated. Failure to properly adjust for this heterogeneity risks missing important subgroup effects in, for example, the interaction of treatment with varying levels of baseline risk. When subgroups are defined by characteristics that vary within constituent trials (such as age) rather than features constant within each trial (such as drug dose), there is the additional risk of incorrect conclusions due to the ecological fallacy. The present review explains these problems and the strategies by which they are overcome.

After-hours discharge from intensive care increases the risk of readmission and death

Despite reports showing night discharge from an intensive care unit (ICU) is associated with increased mortality, it is unknown if this has resulted in changes in practice in recent years. Our aim was to determine prevalence, trends and effect on patient outcome of discharge timing from ICU throughout Australia and New Zealand. Two datasets from the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS APD) were examined: (1) All submissions to the APD from 1.1.2003 to 31.12.2004 to determine contemporary practices. (2) Forty hospitals which had submitted continuous data between 1.1.2000 and 31.12.2004 to determine trends in practice over time. Outcomes investigated were hospital mortality and ICU readmission rate. Between 1.1.2003 and 31.12.2004, the ANZICS APD reported 76,690 patients discharged alive from ICU; 13,968 (18.2%) were discharged after-hours (between 1800 and 0559 hours). After-hours discharges had a higher readmission rate (6.3% vs. 5.1%; P < or = 0.0001) and higher mortality (8.0% vs. 5.3%; P = < 0.0001). Peak readmission (8.6%) and mortality rates (9.7%) were seen in patients discharged between 0300 and 0400 hours. After-hours discharge was a predictor of mortality (odds ratio 1.42, 95% confidence interval 1.32-1.52; P= < 0.0001) in multivariate analysis. Between 2000 and 2004, after-hours discharges increased (P = 0.0015) with seasonal peaks during winter The risk of death increased as the proportion of patients discharged after-hours rose. After-hours discharge from ICU is associated with increased risk of death and readmission to ICU. It has become more frequent. The risk of death increases as more after-hours discharges occur.

Stereoscopic evaluation of fetal bony structures

OBJECTIVE

The purpose of this study was to assess the performance of stereoscopic compared with conventional viewing of 3-dimensional ultrasound (3DUS) data for evaluation of fetal bony structures.

METHODS

A series of 47 human fetuses were evaluated with conventional 3DUS scanning systems. Twenty-five volumes of the fetal head, thorax, and abdomen were acquired. Volume-rendered images of the fetal cranium and spine were displayed interactively on a real-time stereoscopic graphics workstation. Visualization parameters were interactively optimized. Both conventional and stereoscopic images were evaluated for the clarity of structure visualization (0, nonvisualized; 1, nondiagnostic; 2, adequate; and 3, excellent), the ability to identify key anatomic landmarks (eg, sutures, palate, vertebrae, and ribs), artifacts, and evaluation time.

RESULTS

Fetal bony structures, especially high-contrast structures, were readily identified with both conventional and stereoscopic. Overall, stereoscopic viewing provided a statistically significant improvement compared with conventional viewing (P < .01), improved conspicuity of complex bony structures, and added structural detail information that assisted in identification of complex anatomy in 14% of the fetal skull and 26% of the fetal spine cases. Overlapping structures were better identified on the volume-rendered stereoscopic display, with stereoscopic viewing improving differentiation of near and far structures. An interactive display and inclusion of a planar slice review further assisted in identification of structures. The evaluation times were comparable for the two methods.

CONCLUSIONS

The stereoscopic display of rendered 3DUS data adds valuable information that assists in identification of fetal bony structures, such as cranial sutures and spinal vertebrae, particularly in complex formations. The increasing availability of stereoscopic visualization workstations will offer an additional tool for fetal diagnosis and evaluation.

Long-stay patients in Australian and New Zealand intensive care units: demographics and outcomes

AIM AND METHODS

There is no consensus definition on what constitutes a long stay in the intensive care unit, and little published information on the demographic characteristics, resource usage or outcomes of long-stay patients. We used data from the Australian and New Zealand Intensive Care Society Adult Patient Database to identify patients who had spent > 21 days in the ICU. We examined their resource usage, hospital type, diagnoses and outcomes, and trends in these characteristics over 5 years (2000-2004).

RESULTS

6,565 patients (2.3% of all ICU patients) had one or more admissions > 21 days and accounted for 23% of total ICU bed-hour usage. Long-stay patients had a mean (SD) age of 60.3 (15.3) years and an APACHE III-J risk of death of 32.7% (21.3%). Metropolitan and tertiary hospitals had the highest proportions of long-stay patients. The three diagnoses most strongly associated with long ICU stay were neuromuscular disease (odds ratio [OR], 13.3; 95% CI, 10.2-17.4; P < 0.001), burns (OR, 6.0; 95% CI, 4.9-7.3; P < 0.001) and cervical spine injury (OR, 5.1; 95% CI, 3.4-7.5; P < 0.001), while the most common diagnosis was pneumonia (12.7% of total). During the period 2000- 2004, there was no significant change in the proportion, age, resource usage or outcomes of these patients. Overall observed mortality was 28% (predicted, 32.7%; 95% CI, 31.4%-34.5%). Of those aged >or= 80 years, 37% were discharged home, and 39% died.

CONCLUSIONS

Patients who spend > 21 days in the ICU use significant resources but appear to have worthwhile outcomes in all age brackets.

NeuroD1: developmental expression and regulated genes in the rodent pineal gland

NeuroD1/BETA2, a member of the bHLH transcription factor family, is known to influence the fate of specific neuronal, endocrine and retinal cells. We report here that NeuroD1 mRNA is highly abundant in the developing and adult rat pineal gland. Pineal expression begins in the 17-day embryo at which time it is also detectable in other brain regions. Expression in the pineal gland increases during the embryonic period and is maintained thereafter at levels equivalent to those found in the cerebellum and retina. In contrast, NeuroD1 mRNA decreases markedly in non-cerebellar brain regions during development. Pineal NeuroD1 levels are similar during the day and night, and do not appear to be influenced by sympathetic neural input. Gene expression analysis of the pineal glands from neonatal NeuroD1 knockout mice identifies 127 transcripts that are down-regulated (>twofold, p < 0.05) and 16 that are up-regulated (>twofold, p < 0.05). According to quantitative RT-PCR, the most dramatically down-regulated gene is kinesin family member 5C ( approximately 100-fold) and the most dramatically up-regulated gene is glutamic acid decarboxylase 1 ( approximately fourfold). Other impacted transcripts encode proteins involved in differentiation, development, signal transduction and trafficking. These findings represent the first step toward elucidating the role of NeuroD1 in the rodent pinealocyte.

Blood transfusion requirements for patients undergoing chemotherapy for acute myeloid leukemia how much is enough?

Although essential in the management of AML, there is little information quantitating transfusion requirements for these patients. We evaluated 111 consecutive adults treated for AML, showing that approximately 150 blood donors are required to adequately cater for a single patient's complete therapy with little variation for age, prognostic group or intensity of treatment.

Daily rhythm in pineal phosphodiesterase (PDE) activity reflects adrenergic/3',5'-cyclic adenosine 5'-monophosphate induction of the PDE4B2 variant

The pineal gland is a photoneuroendocrine transducer that influences circadian and circannual dynamics of many physiological functions via the daily rhythm in melatonin production and release. Melatonin synthesis is stimulated at night by a photoneural system through which pineal adenylate cyclase is adrenergically activated, resulting in an elevation of cAMP. cAMP enhances melatonin synthesis through actions on several elements of the biosynthetic pathway. cAMP degradation also appears to increase at night due to an increase in phosphodiesterase (PDE) activity, which peaks in the middle of the night. Here, it was found that this nocturnal increase in PDE activity results from an increase in the abundance of PDE4B2 mRNA (approximately 5-fold; doubling time, approximately 2 h). The resulting level is notably higher (>6-fold) than in all other tissues examined, none of which exhibit a robust daily rhythm. The increase in PDE4B2 mRNA is followed by increases in PDE4B2 protein and PDE4 enzyme activity. Results from in vivo and in vitro studies indicate that these changes are due to activation of adrenergic receptors and a cAMP-dependent protein kinase A mechanism. Inhibition of PDE4 activity during the late phase of adrenergic stimulation enhances cAMP and melatonin levels. The evidence that PDE4B2 plays a negative feedback role in adrenergic/cAMP signaling in the pineal gland provides the first proof that cAMP control of PDE4B2 is a physiologically relevant control mechanism in cAMP signaling.

Investigation into the impact of couch sag on delivered dose

The effect of couch sag on treatment delivery accuracy has been investigated by modelling the variation of delivered dose from planned dose due to the difference between the treatment and simulation couches. The couch sag of the Siemens (Concord, USA) Primus linac was determined relative to the couch sag of the Siemens (Germany) Sensation 4 CT Scanner. A phantom planning study was then undertaken to evaluate the likely clinical impact of the couch sag through an evaluation of changes in dose distribution, dose volume histograms and monitor units. The couch sag was simulated by altering the angle of the CT gantry when obtaining image studysets. A second investigation into the effects of couch sag was undertaken using an existing patient CT studyset. For this investigation, the couch sag was simulated by appropriate rotation of the gantry and collimator angles. The effect of couch sag on calculated monitor units (MU) was found to be statistically insignificant. The small monitor unit changes observed were likely to result from differences in the average linear attenuation coefficient along the beam path to the isocentre. The major differences seen however were in the regions away from the central axis. The dose volume histograms showed that both the bladder and rectum were further spared with increasing tilt angle whilst the PTV dose was unchanged. The only issue at South West Sydney Cancer Services (SWSCS) in terms of patient position variation arises from the angle induced by the couch sag (or more precisely, the difference in couch sag angle between the CT and Linac couches). Due to the relatively uniform structures (of PTV, bladder and rectum), and the proximity of these critical structures to the isocentre, this angular rotation about the isocentre did not cause any major variations to the DVH, MU and isodoses for realistic levels of couch sag (i.e. less than 20mm).

No rest for the wounded: early ambulation after hip surgery accelerates recovery

BACKGROUND

Level 3 evidence-based guidelines recommend first walk after hip fracture surgery within 48 h. Early mobilization is resource and effort intensive and needs rigorous investigation to justify implementation. This study uses a prospective randomized method to investigate the effect of early ambulation (EA) after hip fracture surgery on patient and hospital outcomes.

METHODS

Sixty patients (41 women and 19 men; mean age 79.4 years) admitted between March 2004 through December 2004 to The Alfred Hospital, Melbourne, for surgical management of a hip fracture were studied. Randomization was either EA (first walk postoperative day 1 or 2) or delayed ambulation (DA) (first walk postoperative day 3 or 4). Functional levels on day 7 post-surgery, acute hospital length of stay and destination at discharge were compared.

RESULTS

At 1 week post-surgery, patients in the EA group walked further than those in the DA group (P = 0.03) and required less assistance to transfer (P = 0.009) and negotiate a step (P = 0.23). Patients in the EA group were more likely to be discharged directly home from the acute care than those in the DA group (26.3 compared with 2.4%) and less likely to need high-level care (36.8 compared with 56%). A failed early ambulation subgroup had significantly more postoperative cardiovascular instability and worse results for all outcome measures.

CONCLUSION

EA after hip fracture surgery accelerates functional recovery and is associated with more discharges directly home and less to high-level care.

Relation of interlobar collaterals to radiological heterogeneity in severe emphysema

BACKGROUND

A study was undertaken to assess the prevalence of interlobar collateral ventilation in patients with severe emphysema to identify factors that may help to predict patients with significant collateral ventilation.

METHODS

Between April 2002 and August 2003, ex vivo assessment of the lungs 17 consecutive patients with smoking related severe emphysema was performed. To assess collateral flow, all lobes of explanted specimens were selectively intubated using a wedged cuffed microlaryngeal intubation tube and then manually ventilated using a bagging circuit. Interlobar collateral ventilation was defined as the ability to easily inflate a non-intubated lobe at physiological pressures. Pre-transplant demographic characteristics, physiological data, radiological results, and explant histology were assessed for retrospective relationships with the degree of interlobar collateral ventilation in the explanted lung.

RESULTS

A total of 23 lungs were evaluated, 15 of which (66%) had significant collateral interlobar airflow. There were no significant differences in any demographic, physiological, or pathological variables between patients with collateral ventilation and those with no collateral ventilation. However, there was a significant relationship between the presence of interlobar collateral ventilation and radiological scores (p<0.05).

CONCLUSIONS

Interlobar collateral ventilation occurs to a much greater extent in patients with radiologically homogeneous emphysema than in those with heterogeneous emphysema. Heterogeneity of emphysema may predict patients with a significantly reduced risk of interlobar collateral ventilation.

Focal MIBI uptake is a better indicator of active myeloma than diffuse uptake

PURPOSE

Technetium-99m 2-methoxyisobutylisonitrile (MIBI) imaging has been proposed as a front-line investigation to detect bone disease both before and after the treatment of myeloma. In this study, we have compared the pattern of MIBI uptake (focal and diffuse) between patients with proven myeloma and a cohort of patients without myeloma, in order to identify the uptake pattern that best correlates with disease activity.

METHODS

Nineteen scans were taken in 16 consecutive patients (nine males and seven females: aged 39-71 yr) with active myeloma. A further 20 scans (10 subjects having MIBI myocardial perfusion scintigraphy and 10 subjects having MIBI parathyroid adenoma localisation studies), comprised the control (non-myeloma) cohort. Scans were evaluated in a double-blinded fashion by two observers for any diffuse skeletal MIBI uptake (homogeneous uptake in spine, sternum and/or long bones), and/or abnormal focal uptake (patchy, focal or tubular uptake in the skeleton or soft tissues).

RESULTS

The pattern of MIBI uptake was significantly different in the myeloma-positive subjects and the control cohort. Focal uptake was highly discriminatory, being seen in 15 of 19 (79%) scans of the myeloma-positive group as opposed to one of 20 (5%) scans of the control group (P < 0.0001). In contrast, diffuse uptake was seen in 17 of 19 (89%) scans in patients with myeloma, and in 11 of 20 (55%) of the control cohort (P = 0.02). Using multiple logistic regression analysis, any focal uptake was significantly predictive for active myeloma (P = 0.0007) but diffuse uptake was not (P = 0.15). Diffuse uptake alone, without focal uptake, was found in four of 19 scans with myeloma and in 10 of 20 without active myeloma, but was not significantly associated with absence of active myeloma (P = 0.06). Using the criteria of Pace et al. for positivity (diffuse activity >50% myocardial activity), we demonstrated improved specificity from 45% to 100%, but significantly impaired sensitivity for presence of myeloma (79% vs. 37%, P = 0.02).

CONCLUSION

Our study thus illustrates that the presence of any focal uptake of MIBI is useful in indicating active myeloma whereas diffuse uptake is not.

Effects of Silybum marianum on serum hepatitis C virus RNA, alanine aminotransferase levels and well-being in patients with chronic hepatitis C

BACKGROUND/AIMS

Silybum marianum is a herbal preparation commonly used by subjects with chronic hepatitis C (CHC). The aims of this pilot study were to assess the efficacy and safety of S. marianum on serum hepatitis C virus (HCV) RNA, alanine aminotransferase levels and well-being in patients with CHC.

METHODS

Twenty-four subjects with CHC were enrolled into a randomized, double-blind, placebo-controlled, crossover study. Subjects received 12 weeks of S. marianum (either 600 mg or 1200 mg/day) and placebo separated by a 4-week washout interval. Baseline biochemical, virological, psychological and quality-of-life tests were performed, with biochemical tests repeated monthly, and HCV RNA titer and quality-of-life and psychological assessments repeated at the end of both treatment periods.

RESULTS

Seventeen patients completed the trial. Mean changes in HCV RNA titers, serum ALT levels and Short Form-36 scores were not significantly different for subjects on S. marianum compared to those on placebo. There was no significant change in mean State-Trait Anxiety Inventory State-Anxiety scores on S. marianum from baseline. Adverse events were similar with S. marianum and placebo.

CONCLUSIONS

S. marianum is well tolerated in subjects with CHC, but does significantly affect serum HCV RNA, alanine aminotransferase levels, quality of life or psychological well-being in subjects with this condition.

Road traffic injuries in the elderly

OBJECTIVE

Elderly victims of motor vehicle collisions are increasing with the aging population. This study aimed to investigate the injury pattern of elderly victims involved in motor vehicle collisions.

METHODS

This was a retrospective study using data from the Victorian State Trauma Outcome Registry and Monitoring Group (VSTORM) from June 2001 to July 2003, Australian Bureau of Statistics year 2001 population estimates, and Victoria Transport Accident Commission year 2001 total road death toll. Elderly victims were defined as age 65 and above. Comparison of fatality rates and general injury patterns for the elderly and young victims was undertaken.

RESULTS

The total fatality rate of the elderly group was almost double that of the younger group. The elderly victims had a higher rate of chest injuries (23.42% v 18.17%; p = 0.003). The three most common chest injuries of the elderly victims were rib fractures (23.58%), flail chest (9.55%), and sternum fractures (5.97%). Elderly chest injured patients also had longer intensive care unit stay compared with the younger group (7.96 days v 5.31 days; p = 0.048).

CONCLUSIONS

Elderly victims of motor vehicle collisions have a higher risk of chest injuries, especially of chest wall injuries. Age specific injury patterns are important in determining primary and secondary prevention strategies.

A six-month, supervised, aerobic and resistance exercise program improves self-efficacy in people with human immunodeficiency virus: A randomised controlled trial

QUESTION

What is the effect of a six-month, supervised, aerobic and resistance exercise program on self-efficacy in men living with human immunodeficiency virus (HIV)?

DESIGN

Randomised, controlled trial.

PARTICIPANTS

40 (5 dropouts) men living with HIV, aged 18 years or older.

INTERVENTION

The experimental group participated in a twice-weekly supervised aerobic and resistance exercise program for six months and the control group participated in a twice-weekly unsupervised walking program and attended a monthly group forum.

OUTCOME MEASURES

The primary outcome measure was self-efficacy using the General Self-Efficacy Scale. Secondary outcome measures were cardiovascular fitness using the Kasch Pulse Recovery test, and health-related quality of life using the Medical Outcomes Study HIV Health Survey. Measures were taken by an assessor blinded to group allocation.

RESULTS

By six months, the experimental group had improved their self-efficacy by 6.8 points (95% CI 3.9 to 9.7, p < 0.001) and improved their cardiovascular fitness by reducing their heart rate by 20.2 bpm (95% CI -25.8 to -14.6, p < 0.001) more than the control group. Health-related quality of life improved in only two out of the eleven dimensions: the experimental group improved their overall health by 20.8 points (95% CI 2.0 to 39.7, p = 0.03) and their cognitive function by 14 points (95% CI 0.7 to 27.3, p = 0.04) more than the control group.

CONCLUSION

The findings of this study add to the known benefits of exercise for the HIV-infected population.

High Donor Age, Low Donor Oxygenation, and High Recipient Inotrope Requirements Predict Early Graft Dysfunction in Lung Transplant Recipients

BACKGROUND

Early dysfunction in lung transplants is characterized by poor oxygenation, which may then lead to prolonged mechanical ventilation. This may be due to a combination of donor, recipient, and management factors. Our aim was to determine the incidence and severity of hypoxia and graft dysfunction and which factors were directly associated with poor oxygenation within the first 24 hours after lung transplantation.

METHODS

A retrospective study of all 128 lung transplants between 1999 and 2002 was undertaken. Multiple linear regression analysis was performed to determine which donor, recipient, operative, and intensive care unit (ICU) parameters were associated with the worst recorded arterial blood gas partial pressure of oxygen (PAO2)/fraction of inspired oxygen (FIO2) ratio in the initial 24 hours after operation.

RESULTS

Eighty-three percent of the patients (104 of 128) had a PAO2/FIO2 ratio below 300 within the first 24 hours post-transplantation, and 60% (77 of 128) had a PAO2/FIO2 ratio below 200. A high donor age (p = 0.004), low donor PAO2 (p = 0.007), and high post-operative inotrope requirements (p = 0.02) were correlated with a low PAO2/FIO2 ratio. Recipient diagnosis, ischemic time, use of cardiopulmonary bypass, fluid balance in the ICU, and cardiac index were not related. There was no difference in the long-term outcomes of patients with high or low PAO2/FIO2 ratios.

CONCLUSIONS

A low PAO2/FIO2 ratio is a common finding in the first 24 hours after lung transplantation. Donor factors such as age and PAO2, and the need for increasing inotrope requirements in ICU predict early graft dysfunction and hypoxia.

Male to male sex is associated with a high prevalence of exposure to GB virus C

Co-infection with GB virus C (GBV-C) and human immunodeficiency virus (HIV) appears to reduce mortality for HIV/AIDS. Epidemiological and demographic factors for GBV-C were examined prospectively in 167 subjects at risk for co-infection. We attempted to establish a hierarchical exposure risk for GBV-C. Overall exposure to GBV-C was 45.5%. In univariate analysis, GBV-C was associated with male to male sex (P<0.0001), HIV infection (P=0.0005) and hepatitis B infection (P=0.006). Injecting drug use approached statistical significance (P=0.08) while being a female sex worker was not associated with GBV-C exposure/infection (P=0.85). Exposure to GBV-C in 192 healthy blood donors was found to be 9.4%. In conclusion, the data suggest that male to male sex is a more effective mode of transmission of GBV-C and that GBV-C is associated with HIV co-infection. As male to male sex is also a risk factor for HIV transmission our data suggest that many may benefit from the potential protective effect GBV-C exerts on HIV-infected persons.

Hepatic steatosis in chronic hepatitis B and C: predictors, distribution and effect on fibrosis

BACKGROUND/AIMS

Chronic hepatitis B (CHB) and C (CHC) are commonly associated with hepatic steatosis. The aims of this study were to investigate predictors of hepatic steatosis, and their impact on inflammation and fibrosis in CHB and CHC.

METHODS

Consecutive patients with either CHB or CHC who underwent a liver biopsy at The Alfred Hospital between April and September 2002 were included. Histological analysis of liver biopsies was performed by two hepatopathologists blinded to the clinical data.

RESULTS

Ninety-one patients were analysed including 17 patients with CHB and 74 with CHC. CHC genotype 3, C-peptide, glucose and waist circumference were independent predictors of extent of Brunt steatosis grade, while CHC genotype 3, C-peptide and waist circumference were independent predictors of microvesicular steatosis grade. Alcohol intake and age were predictors of hepatic fibrosis. There was a trend toward a correlation between both Brunt steatosis and microvesicular steatosis grades and fibrosis progression rate in CHC genotype non-3.

CONCLUSIONS

Hepatic steatosis is common in chronic hepatitis B and C, and is associated with waist circumference, glucose, C-peptide and chronic hepatitis C genotype 3. Steatosis grade appears to relate to hepatic fibrosis progression rate in chronic hepatitis C genotype non-3.

Evaluation of the oxygenation ratio in the definition of early graft dysfunction after lung transplantation

OBJECTIVE

Despite the clinical importance of early graft dysfunction, no standardized definition is available. We hypothesized that the arterial blood gas oxygen tension/fraction of inspired oxygen ratio (PaO2 /FIO2) would prove to be a useful marker for predicting subsequent outcomes of early graft dysfunction. The aims of this study were to define the prevalence of various ranges of PaO2 /FIO2 over the first 48 hours after lung transplantation and to evaluate which measurement using the PaO2 /FIO2 best correlates with the duration of intubation, the length of stay in the intensive care unit, and 30-day mortality, which are important alternative indicators of early graft performance.

METHODS

A retrospective study was performed that included all 68 bilateral single-lung transplantations at The Alfred Hospital from January 2000 to December 2002.

RESULTS

PaO2 /FIO2 at 6 and 12 hours after admission to the intensive care unit was significantly associated with the duration of intubation ( r = -0.44; P < .001 and r = -0.48; P < .001, respectively), and PaO2 /FIO2 at 6 and 24 hours was also significantly associated with the length of intensive care unit stay ( r = -0.38; P = .002 and r = -0.44; P = .001, respectively). Thirty-day mortality was significantly associated with a lower PaO2 /FIO2 at 6 hours (219 +/- 93 vs 306 +/- 101; P = .03).

CONCLUSIONS

PaO2 /FIO2 taken between 6 and 12 hours after transplantation is a useful marker associated with lung transplantation outcomes. There is the potential for therapeutic interventions during this time that may be able to enhance PaO2 /FIO2 by 12 hours and improve subsequent outcomes.

Successful mobilization of peripheral blood stem cells using recombinant human stem cell factor in heavily pretreated patients who have failed a previous attempt with a granulocyte colony-stimulating factor-based regimen

To assess the efficacy of recombinant human stem cell factor (rHuSCF), 48 patients who had failed to mobilize >2.0 x 10(6) CD34+ cells/kg with granulocyte colony-stimulating factor (G-CSF) (10 microg/kg twice daily) with, or without, concomitant chemotherapy (G-CSF-based regimen), were remobilized with the addition of rHuSCF (20 microg/kg/day). In all, 18/48 (38%) achieved a total of >2.0 x 10(6) CD34+ cells/kg with the second rHuSCF-based mobilisation alone and 29/48 (60%) achieved a cumulative total of >2.0 x 10(6) CD34+ cells/kg following remobilization. Inclusion of chemotherapy in the mobilization regimen resulted in a higher yield of CD34+ cells/kg for both the initial G-CSF-based and subsequent rHuSCF-based regimens (0.90 vs 0.54, P < 0.01 and 2.36 vs 1.34, P < 0.01, respectively). The total peripheral blood stem cells PBSC collected from the G-CSF-based regimen, performance status, baseline platelet count and albumin were significantly associated with successful remobilization. Patients with multiple myeloma were also more likely to successfully remobilize. There was no threshold of total collected from the failed G-CSF-based regimen below which successful remobilization with the rHuSCF-based regimen was not possible. We therefore propose a predictive model [PBSC expected = 0.6+(G-CSF-based total collection)+2 (rHuSCF-based day 1 collection)] to calculate the cumulative total of PBSC expected following a maximum of five leukaphereses. This algorithm may permit the early identification of patients who are unlikely to achieve sufficient PBSC for transplantation and allow physicians to direct the resources involved in PBSC collection in a more appropriate and economical manner.

Stereolithographic vascular replicas from CT scans: choosing treatment strategies, teaching, and research from live patient scan data

Our goal was to develop a system that would allow us to recreate live patient arterial pathology by using an industrial technique known as stereolithography (or rapid prototyping). In industry, drawings rendered into dicom files can be exported to a computer programmed to drive various industrial tools. Those tools then make a 3D structure shown by the original drawings. We manipulated CT scan dicom files to drive a stereolithography machine and were able to make replicas of the vascular diseases of three patients.