PubMed Health⌕ Search

Biomedical subjects

John Granton

Publications and source records attributed to John Granton.

15 recordsLinked to original sources
PubMed2006

In-house, overnight physician staffing: a cross-sectional survey of Canadian adult and pediatric intensive care units.

OBJECTIVE: Physician staffing is an important determinant of patient outcomes following intensive care unit (ICU) admission. We conducted a national survey of in-house after-hours physician staffing in Canadian ICUs. DESIGN: : Cross-sectional survey. SETTING: Canadian adult and pediatric ICUs. PARTICIPANTS: ICU directors. INTERVENTIONS: ICU directors of Canadian adult and pediatric ICUs were surveyed to describe overnight staffing by interns, residents, critical care medicine trainees, clinical assistants, and ICU physicians in their ICUs. MEASUREMENTS AND MAIN RESULTS: Data were collected regarding hospital and ICU demographics and ICU staffing. For ICUs with in-house overnight physicians, we documented physician experience, shift duration, and clinical responsibilities outside the ICU. We identified 98 Canadian ICU directors, of whom 88 (90%) responded. Dedicated in-house physician coverage overnight was reported in 53 (60%) ICUs, including 13 (15%) in which ICU staff physicians stayed in-house overnight. Compared with ICUs without in-house physicians, those with in-house physicians had more ICU beds (15 vs. 8.5, p=.0001) and fewer ICU staff physicians (5 vs. 7, p=.03). For the 271 physicians who provide overnight staffing, the median level of postgraduate experience was 3 yrs (range, <1 yr, >10 yrs); 129 (48%) had <3 months of ICU experience. Most shifts (83%) were >20 hrs long. CONCLUSIONS: In-house overnight physician staffing in Canadian ICUs varies widely. Only a minority of ICUs comply with the 2003 Society of Critical Care Medicine guidelines for adult ICUs recommending continuous in-house staffing by ICU staff physicians. The duration of most ICU shifts raises concern about workload-associated fatigue and medical error. The impact of current nighttime staffing requires further evaluation with respect to patient outcomes.

Adult↗
PubMed2006

Update of early respiratory failure in the lung transplant recipient.

PURPOSE OF REVIEW: Respiratory failure remains the most common complication in the perioperative period after lung transplantation. Consequently it is important to develop an approach to diagnosis and the treatment of respiratory failure in this population. This review highlights the advances made in the understanding and treatment of lung transplant patients in the early postoperative phase. Owing to its relative importance, advances in the understanding and treatment of ischaemia-reperfusion injury are highlighted. RECENT FINDINGS: The causes of respiratory failure and the complications seen after transplantation are time dependent, with ischaemia-reperfusion, infection, technical problems and acute rejection being the most common in the early perioperative phase, and obliterative bronchiolitis, rejection, and infections secondary to bacteria, fungi, and viruses becoming more prevalent after 3 months. The advances in lung preservation and postoperative care may be overshadowed by an increase in the complexity of the recipients and the use of more marginal organs. An improved mechanistic understanding of ischaemia-reperfusion injury has translated into potential therapeutic targets. The development of prospective clinical trials, however, is hampered by a relatively small sample of patients and a significant degree of heterogeneity in the lung transplant population. SUMMARY: Many advances have been made in the understanding of ischaemia-reperfusion injury. Owing to the acute and long-term implications of this complication, interventions that reduce the risk of developing ischaemia-reperfusion need to be evaluated in prospective clinical trials.

Clinical Trials as Topic↗
PubMed2005

Bone morphogenetic protein receptor-2 signaling promotes pulmonary arterial endothelial cell survival: implications for loss-of-function mutations in the pathogenesis of pulmonary hypertension.

Mutations in the bone morphogenetic protein (BMP) receptor-2 (BMPR2) have been found in patients with idiopathic pulmonary arterial hypertension (IPAH); however, the mechanistic link between loss of BMPR2 signaling and the development of pulmonary arterial hypertension is unclear. We hypothesized that, contrary to smooth muscle cells, this pathway promotes survival in pulmonary artery endothelial cells (ECs) and loss of BMPR2 signaling will predispose to EC apoptosis. ECs were treated with BMP-2 or BMP-7 (200 ng/mL) for 24 hours in regular or serum-free (SF) medium, with and without addition of tumor necrosis factor alpha, and apoptosis was assessed by flow cytometry (Annexin V), TUNEL, or caspase-3 activity. Treatment for 24 hours in SF medium increased apoptosis, and both BMP-2 and BMP-7 significantly reduced apoptosis in response to serum deprivation to levels not different from serum controls. Transfection with 5 microg of small interfering RNAs for BMPR2 produced specific gene silencing assessed by RT-PCR and Western blot analysis. BMPR2 gene silencing increased apoptosis almost 3-fold (P=0.0027), even in the presence of serum. Circulating endothelial progenitor cells (EPCs) isolated from normal subjects or patients with IPAH were differentiated in culture for 7 days and apoptosis was determined in the presence and absence of BMPs. BMP-2 reduced apoptosis induced by serum withdrawal in EPCs from normal subjects but not in EPCs isolated from patients with IPAH. These results support the hypothesis that loss-of-function mutations in BMPR2 could lead to increased pulmonary EC apoptosis, representing a possible initiating mechanism in the pathogenesis of pulmonary arterial hypertension.

Adult↗
PubMed2005

Atrial septal defect closure in a patient with "irreversible" pulmonary hypertensive arteriopathy.

The presence of irreversible pulmonary hypertension in patients with atrial septal defect (ASD) is thought to preclude shunt closure. We report the case of a woman with plexiform pulmonary arteriopathy secondary to an ostium secundum ASD who was able to successfully undergo percutaneous shunt closure following therapy with chronic intravenous prostacyclin (Flolan). One year after closure, the patient was weaned off Flolan over a period of 7 months following the institution of oral Bosentan therapy. Our case illustrates how aggressive vasodilator therapy with prostaglandins may be capable of reducing pulmonary artery pressure and permitting shunt closure in a patient once considered to have "inoperable" pulmonary arteriopathy.

Adult↗
PubMed2005

Prophylaxis of Thromboembolism in Critical Care (PROTECT) Trial: a pilot study.

PURPOSE: There is no randomized trial comparing low-molecular weight heparin (LMWH) and unfractionated heparin (UFH) for thromboprophylaxis in medical-surgical ICU patients. The primary objective of this randomized pilot study on LMWH vs UFH was to assess the feasibility of conducting a large randomized trial with respect to timely enrollment and blinded study drug administration, practicality of twice-weekly lower limb ultrasounds to screen for deep venous thrombosis, LMWH bioaccumulation and dose adjustment in renal insufficiency, and recruitment rates for a future trial in medical-surgical intensive care unit (ICU) patients. Its additional goals were to evaluate the suitability of the exclusion criteria and to document the range of research activities that precede accrual of patients into a trial to plan multisite management. MATERIALS AND METHODS: By computerized telephone randomization, we allocated 129 medical-surgical ICU patients to treatment with dalteparin 5,000 IU QD SC or that with UFH 5,000 IU BID SC. Within each clinical center, only the study pharmacist was not blinded. We performed bilateral lower limb compression ultrasounds within 48 hours of ICU admission, twice weekly, on suspicion of deep venous thrombosis, and 7 days after ICU discharge. Research coordinators and investigators at 7 centers reported the time they engaged in all research activities before the first patient was randomized. RESULTS: Timely complete study drug administration occurred after enrollment. More than 99% of scheduled doses were administered in a blinded fashion. Scheduled ultrasounds were performed without exception. No bioaccumulation of dalteparin was observed when creatinine clearance decreased to lower than 30 mL/min. Average recruitment was 2 patients/center per month before the study exclusion criteria were modified. Study startup activities required, on average, 65.5 hours of combined investigator and research coordinator time at each center. Careful examination of the accrual in the pilot study led to a reexamination of the Prophylaxis of Thromboembolism in Critical Care Trial (PROTECT) study exclusion criteria. CONCLUSIONS: This pilot study suggests that a multicenter randomized clinical trial comparing LMWH with UFH in critically ill medical-surgical patients is feasible. Pilot studies can improve the design of larger trials and may enhance successful timely completion.

Anticoagulants↗
PubMed2005

Canadian Cardiovascular Society and Canadian Thoracic Society position statement on pulmonary arterial hypertension.

The Canadian Cardiovascular Society and the Canadian Thoracic Society requested a position statement on pulmonary arterial hypertension from leading Canadian experts. The present document is intended to act as an update for the clinician, to provide a template for the initial evaluation of patients, to enable the understanding of current therapeutic paradigms based on approved indications for Canada, to highlight new therapies on the horizon, and to state the positions of the Canadian Cardiovascular Society and the Canadian Thoracic Society on resource management for pulmonary arterial hypertension in Canada.

Humans↗
PubMed2005

Canadian Cardiovascular Society and Canadian Thoracic Society position statement on pulmonary arterial hypertension.

The Canadian Cardiovascular Society and the Canadian Thoracic Society requested a position statement on pulmonary arterial hypertension from leading Canadian experts. The present document is intended to act as an update for the clinician, to provide a template for the initial evaluation of patients, to enable understanding of current therapeutic paradigms based on approved indications for Canada, to highlight new therapies on the horizon, and to state the positions of the Canadian Cardiovascular Society and the Canadian Thoracic Society on resource management for pulmonary arterial hypertension in Canada.

Canada↗
PubMed2004

Critical care procedure logging using handheld computers.

INTRODUCTION: We conducted this study to evaluate the feasibility of implementing an internet-linked handheld computer procedure logging system in a critical care training program. METHODS: Subspecialty trainees in the Interdepartmental Division of Critical Care at the University of Toronto received and were trained in the use of Palm handheld computers loaded with a customized program for logging critical care procedures. The procedures were entered into the handheld device using checkboxes and drop-down lists, and data were uploaded to a central database via the internet. To evaluate the feasibility of this system, we tracked the utilization of this data collection system. Benefits and disadvantages were assessed through surveys. RESULTS: All 11 trainees successfully uploaded data to the central database, but only six (55%) continued to upload data on a regular basis. The most common reason cited for not using the system pertained to initial technical problems with data uploading. From 1 July 2002 to 30 June 2003, a total of 914 procedures were logged. Significant variability was noted in the number of procedures logged by individual trainees (range 13-242). The database generated by regular users provided potentially useful information to the training program director regarding the scope and location of procedural training among the different rotations and hospitals. CONCLUSION: A handheld computer procedure logging system can be effectively used in a critical care training program. However, user acceptance was not uniform, and continued training and support are required to increase user acceptance. Such a procedure database may provide valuable information that may be used to optimize trainees' educational experience and to document clinical training experience for licensing and accreditation.

Adult↗
PubMed2004

Clinically important deep vein thrombosis in the intensive care unit: a survey of intensivists.

INTRODUCTION: Outside the intensive care unit (ICU), clinically important deep vein thrombosis (DVT) is usually defined as a symptomatic event that leads to objective radiologic confirmation and subsequent treatment. The objective of the present survey is to identify the patient factors and radiologic features of lower limb DVT that intensivists consider more or less likely to make a DVT clinically important in ICU patients. METHODS: Our definition of clinically important DVT was a DVT likely to result in short-term or long-term morbidity or mortality if left untreated, as opposed to a DVT that is unlikely to have important consequences. We asked respondents to indicate the likelihood that patient factors and ultrasonographic features make a DVT clinically important using a five-point scale (from 1 = much less likely to 5 = much more likely). RESULTS: Of the 71 Canadian intensivists who responded, 70 (99%) rated three patient factors as most likely to make a DVT clinically important: clinical suspicion of pulmonary embolism (mean score 4.6), acute or chronic cardiopulmonary morbidity that might limit a patient's ability to tolerate pulmonary embolism (score 4.5), and leg symptoms (score 4.2). Of the ultrasound features, proximal (score 4.7), large (score 4.2), and totally occlusive (score 3.9) thrombi were considered the three most important. CONCLUSION: When labeling a DVT as clinically important, intensivists rely on different patient specific factors and thrombus characteristics than are used to assess the clinical importance of DVT outside the ICU. The clinical importance of DVT is influenced by unique factors such as cardiopulmonary reserve among mechanically ventilated patients.

Adult↗
PubMed2004

Risk quantification of early outcome after lung transplantation: donor, recipient, operative, and post-transplant parameters.

BACKGROUND: Because there is no reliable evaluation system of recipient acuity after lung transplantation, comparing patients among centers is difficult. The purpose of our study was to identify risk factors for 30-day mortality and prolonged intensive care unit stay and to develop a scoring system to evaluate the severity of impairment and to predict surgical outcomes. METHODS: We prospectively collected data from 122 lung transplant recipients and from 119 donors from January 1997 to June 2000. We assessed donor, recipient, and operative factors; ischemic time; and immediate post-operative physiologic parameters to identify risk factors for 30-day mortality and prolonged intensive care unit stay. Furthermore, we sub-classified these factors into grades to develop a scoring system for predicting surgical outcomes. RESULTS: Cardiopulmonary bypass use, body mass index >25 kg/m2, immediate post-operative systolic pulmonary arterial pressure, trend of oxygenation index from 12 to 24 hours after transplantation, and the Acute Physiology and Chronic Health Evaluation II score correlated significantly with outcomes, and the sum of these 5 scores correlated strongly with outcomes (p < 0.0001). CONCLUSIONS: We conclude that the total score of these 5 risk factors could be used to predict 30-day mortality and prolonged intensive care unit stay. This scoring system also will facilitate standardization among transplant centers in evaluating post-transplant severity of illness.

Female↗
PubMed2004

High-frequency oscillatory ventilation in adults: the Toronto experience.

STUDY OBJECTIVES: To review the clinical experience with high-frequency oscillatory ventilation (HFOV) in three medical-surgical ICUs in Toronto, ON, Canada, and to describe patient characteristics, HFOV strategies, and outcomes. DESIGN AND PATIENTS: Retrospective chart review of all patients treated with HFOV at three academic university-affiliated ICUs since 1998. The data extracted included patient demographics, etiology of respiratory failure, ventilator settings, and gas exchange and cardiovascular data from baseline to 72 h of treatment, as well as at the transition from HFOV to conventional ventilation (CV). Heart rate and BP were recorded at regular intervals in all patients, and hemodynamic data were recorded in 32 patients who had pulmonary artery catheters in place. Cointerventions and ICU mortality were also recorded. MEASUREMENTS AND RESULTS: A total of 156 adults (67 women and 89 men; mean [+/- SD] age, 48 +/- 18 years; mean acute physiology and chronic health evaluation [APACHE] II score, 23.8 +/- 7.5) with severe ARDS (ie, mean Pao(2)/fraction of inspired oxygen [Fio(2)] ratio, 91 +/- 48 mm Hg; mean oxygenation index [OI], 31 +/- 14) who had received CV for a duration of 5.6 +/- 7.6 days underwent 171 trials of HFOV. HFOV was discontinued within 4 h in 19 patients (12%) because of difficulties with oxygenation, ventilation, or hemodynamics. Pao(2)/Fio(2) ratios and OI ([Fio(2) x mean airway pressure x 100]/Pao(2)) improved significantly with the application of HFOV, and this benefit persisted for the 72-h study duration. Significant changes in hemodynamics following HFOV initiation included an increase in central venous pressure and a reduction in cardiac output (throughout the 72 h), and an increase in pulmonary artery occlusion pressure (at 3 and 6 h). Patients were treated with HFOV for 5.1 +/- 6.3 days. The 30-day mortality rate was 61.7%. Pneumothorax occurred in 21.8% of patients, 43.6% of patients were treated with inhaled nitric oxide, and 37.2% of patients were treated with steroids. Independent predictors of mortality on multivariate analysis were older age, higher APACHE II score, lower pH at the initiation of HFOV, and a greater number of days receiving CV prior to HFOV. CONCLUSIONS: HFOV has beneficial effects on Pao(2)/Fio(2) ratios and OI, and may be an effective rescue therapy for adults with severe oxygenation failure. The early institution of HFOV may be advantageous.

APACHE↗
PubMed2003

Influence of systemic inflammatory response syndrome and sepsis on outcome of critically ill infected patients.

The clinical significance of the systemic inflammatory response in infected patients remains unclear. We examined risk factors for hospital mortality in 3,608 intensive care unit patients included in the European Sepsis Study. Patients were categorized as having infection without or with (i.e., sepsis) systemic inflammatory response, severe sepsis, and septic shock, on the first day of infection. Hospital mortality varied from 25 to 60% according to sepsis stage, but did not differ between the first two categories (hazard ratio, 0.94; p = 0.55), whereas there was a grading of severity from sepsis to severe sepsis (1.53, p < 10-4) and septic shock (2.64, p < 10-4). Within each stage, mortality was unaffected by the number of inflammatory response criteria. Prognostic factors identified by Cox regression included comorbid conditions, severity of acute illness and acute organ dysfunction, shock, nosocomial infection, and infection caused by aerobic gram-negative bacilli, enterobacteria, Staphylococcus aureus, and infection from a digestive or unknown source. We conclude that whereas the categorization of infection by the presence of organ dysfunction or shock has strong prognostic significance, infection and sepsis have similar outcomes, unaffected by the presence or number of inflammatory response criteria. Refinement of risk stratification of patients presenting with infection and no organ dysfunction is needed.

Aged↗
PubMed2003

A pilot study of exercise training in adult patients with repaired tetralogy of Fallot.

BACKGROUND: Positive effects of physical training in adults with acquired heart disease have been reported. The role of exercise training in adults with congenital heart disease, however, is less well defined. OBJECTIVES: To assess the level of physical activity in adult patients with repaired tetralogy of Fallot (TOF), as well as the safety and effect of exercise training in these patients. PATIENTS AND METHODS: A questionnaire of physical activity was filled upon entering the study by the participants. Eighteen adult patients with repaired TOF were then randomly assigned to participate in a three-month structured exercise program (exercise group, nine patients) or to continue their usual exercise routine (control group, nine patients). Each patient in the exercise group received an individualized exercise program to be performed three times a week, whereas the control group was told to continue living their life as usual. Cardiopulmonary testing was performed in all patients at baseline (before randomization) and at the end of the study. RESULTS: No death or incidents occurred during the study period. All patients but one were physically inactive at the onset of the study. There was a significant increase in peak oxygen consumption in the exercise group by the end of the study (22.1 mL/kg/min [6 metabolic equivalents (METS)] versus 24.3 mL/kg/min [7 METS], P=0.049), whereas it remained unchanged in the control group (21.8 mL/kg/min [6 METS] versus 22.1 mL/kg/min [6 METS], P=0.825). CONCLUSION: In clinically stable adult patients with repaired TOF, a moderate level of exercise training improves aerobic capacity. Regular exercise should be encouraged in these sedentary patients.

Adult↗
PubMed2002

High-frequency oscillatory ventilation for acute respiratory distress syndrome in adults: a randomized, controlled trial.

Observational studies of high-frequency oscillatory ventilation in adults with the acute respiratory distress syndrome have demonstrated improvements in oxygenation. We designed a multicenter, randomized, controlled trial comparing the safety and effectiveness of high-frequency oscillatory ventilation with conventional ventilation in adults with acute respiratory distress syndrome; 148 adults with acute respiratory distress syndrome (Pa(O2)/fraction of inspired oxygen <or= 200 mm Hg on 10 or more cm H2O positive end-expiratory pressure) were randomized to high-frequency oscillatory ventilation (n = 75) or conventional ventilation (n = 73). Applied mean airway pressure was significantly higher in the high-frequency oscillation group compared with the conventional ventilation group throughout the first 72 hours (p = 0.0001). The high-frequency oscillation group showed early (less than 16 hours) improvement in Pa(O2)/fraction of inspired oxygen compared with the conventional ventilation group (p = 0.008); however, this difference did not persist beyond 24 hours. Oxygenation index decreased similarly over the first 72 hours in both groups. Thirty-day mortality was 37% in the high-frequency oscillation group and was 52% in the conventional ventilation group (p = 0.102). The percentage of patients alive without mechanical ventilation at Day 30 was 36% and 31% in the high-frequency oscillation and conventional ventilation groups, respectively (p = 0.686). There were no significant differences in hemodynamic variables, oxygenation failure, ventilation failure, barotraumas, or mucus plugging between treatment groups. We conclude that high-frequency oscillation is a safe and effective mode of ventilation for the treatment of acute respiratory distress syndrome in adults.

APACHE↗