PubMed Health⌕ Search

Biomedical subjects

Gavin M Joynt

Publications and source records attributed to Gavin M Joynt.

At least 19 recordsLinked to original sources
PubMed2006

Effect of drug concentration on adsorption of levofloxacin by polyacrylonitrile haemofilters.

We studied an in vitro model of continuous venovenous haemofiltration to determine levofloxacin adsorption by polyacrylonitrile (PAN) filters. Four doses of levofloxacin (5, 25, 50 and 100 mg) were used, resulting in circulating concentrations of levofloxacin at 120 min of 3.56+/-0.14, 15.84+/-2.08, 31.42+/-1.95 and 58.23+/-1.10 mg/L, respectively. Adsorption at 2 h was 0.65+/-0.17, 5.99+/-2.49, 12.30+/-2.34 and 30.13+/-1.32 mg, respectively (P<0.001). From 2h to 4h, increasing the blood pump rate and the ultrafiltration rate had no effect on adsorption. When the concentration was decreased from 3.55+/-0.13 mg/L at 4h to 2.16+/-0.11 mg/L at 5 h by addition of lactated Ringer's solution, adsorption decreased from 0.67+/-0.16 mg to 0.21+/-0.25 mg (P<0.05). These data show that adsorption of levofloxacin by PAN haemofilters is concentration dependent and reversible in vitro and suggest that adsorption by haemofilters is unlikely to affect levofloxacin pharmacokinetics significantly in vivo.

Acrylic Resins↗
PubMed2006

Expanding ICU facilities in an epidemic: recommendations based on experience from the SARS epidemic in Hong Kong and Singapore.

Epidemics have the potential to severely strain intensive care resources and may require an increase in intensive care capability. Few intensivists have direct experience of rapidly expanding intensive care services in response to an epidemic. This contribution presents the recommendations of an expert group from Hong Kong and Singapore who had direct experience of expanding intensive care services in response to the epidemic of severe acute respiratory syndrome. These recommendations cover training, infection control, staffing, communication and ethical issues. The issue of what equipment to purchase is not addressed. Early preparations should include fit testing of negative pressure respirators, training of reserve staff, sourcing of material for physical modifications to the ICU, development of infection control policies and training programmes, and discussion of triage and quarantine issues.

Counseling↗
PubMed2006

Avian influenza (H5N1): implications for intensive care.

BACKGROUND: As influenza A/H5N1 spreads around the globe the risk of an epidemic increases. DISCUSSION: Review of the cases of influenza A/H5N1 reported to date demonstrates that it causes a severe illness, with a high proportion of patients (63%) requiring advanced organ support. Of these approx. 68% develop multiorgan failure, at least 54% develop acute respiratory distress syndrome, and 90% die. Disease progression is rapid, with a median time from presentation to hospital to requirement for advanced organ support of only 2 days. CONCLUSION: The infectious nature, severity and clinical manifestations of the disease and its potential for pandemic spread have considerable implications for intensive care in terms of infection control, patient management, staff morale and intensive care expansion.

Animals↗
PubMed2006

Transmission of SARS to healthcare workers. The experience of a Hong Kong ICU.

OBJECTIVE: To describe the extent and temporal pattern of transmission of severe acute respiratory syndrome (SARS) to intensive care unit staff. DESIGN: Retrospective observational cohort study. SETTING: University hospital intensive care unit, caring solely for patients with SARS or suspected to have SARS. PARTICIPANTS: Thirty-five doctors and 152 nurses and healthcare assistants who worked in the ICU during the SARS epidemic. INTERVENTIONS: Infection control measures designed to prevent transmission of disease to staff were implemented. MEASUREMENTS AND RESULTS: Sixty-seven patients with SARS were admitted to the intensive care unit. Four nurses and one healthcare assistant contracted SARS, with three of these developing symptoms within 10 days of admission of the first patient with SARS. Doctors were exposed to patients with SARS for a median (IQR) of 284 (97-376) h, while nurses and healthcare assistants were exposed for a median (IQR) of 119 (57-166) h. The ICU did not meet international standards for physical space or ventilation. CONCLUSIONS: In an ICU in which infection control procedures are rigorously applied, the risk to staff of contracting SARS from patients is low, despite long staff exposure times and a sub-standard physical environment.

Cohort Studies↗
PubMed2006

Noninvasive positive-pressure ventilation: An experimental model to assess air and particle dispersion.

BACKGROUND: Health-care workers are concerned about the risk of acquiring contagious diseases such as severe acute respiratory syndrome and avian influenza after recent outbreaks. We studied exhaled air and particle dispersion through an oronasal mask attached to a human-patient simulator (HPS) during noninvasive positive-pressure ventilation (NPPV). METHODS: Airflow was marked with intrapulmonary smoke for visualization. Therapy with inspiratory positive airway pressure (IPAP) was started at 10 cm H2O and gradually increased to 18 cm H2O, whereas expiratory positive airway pressure was maintained at 4 cm H2O. A leakage jet plume was revealed by a laser light sheet and images captured by video. Smoke concentration in the plume was estimated from the light scattered by smoke particles. FINDINGS: A jet plume of air leaked through the mask exhaust holes to a radial distance of 0.25 m from the mask during the application of IPAP at 10 cm H2O with some leakage from the nasal bridge. The leakage plume exposure probability was highest about 60 to 80 mm lateral to the median sagittal plane of the HPS. Without nasal bridge leakage, the jet plume from the exhaust holes increased to a 0.40-m radius from the mask, whereas exposure probability was highest about 0.28 m above the patient. When IPAP was increased to 18 cm H2O, the vertical plume extended to 0.45 m above the patient with some horizontal spreading along the ward ceiling. CONCLUSION: Substantial exposure to exhaled air occurs within a 0.5-m radius of patients receiving NPPV. Medical wards should be designed with an architectural aerodynamics approach and knowledge of air/particle dispersion from common mechanical ventilatory techniques.

Air Movements↗
PubMed2006

Long-term outcome of acute respiratory distress syndrome caused by severe acute respiratory syndrome (SARS): an observational study.

OBJECTIVE: We examined long-term outcome of pulmonary function, exercise capacity and health-related quality of life (HRQoL) in patients with acute respiratory distress syndrome (ARDS) caused by severe acute respiratory syndrome (SARS). METHODS: 59 critically ill patients with ARDS caused by SARS between March and July 2003 were studied prospectively and followed up for 1 year. Thirty-six underwent pulmonary function testing and a 6-minute walk test, and 35 underwent HRQoL evaluation by Short Form-36 questionnaire at 3, 6, and 12 months after illness onset. RESULTS: Mean age was 47 (SD, 15.7) years. Median APACHE II score was 10 (interquartile range [IQR], 7-12). Only 47% required invasive mechanical ventilation. Median admission and worst PaO2/FIO2 ratio were 142 (IQR, 94-177) mmHg and 86 (IQR, 66-122) mmHg, respectively. Median stay in ICU and hospital were 9 (IQR, 5-20) and 31 (IQR, 20-54) days, respectively. Mortality was 24% at hospital discharge and at 1 year. Mean lung volumes and spirometric measurements were nearly normal by 6 months. Except for diffusion capacity adjusted for haemoglobin concentration (DLCO) measured at 12 months, there was no significant difference in pulmonary function measurement between those who had mechanical ventilation and those who did not. The 6-minute walk distance (6MWD) improved from 3 to 6 months, with no further significant change. Younger patients had near normal HRQoL by 6 months. Those aged over 40 years had impaired HRQoL at multiple domains even at 12 months. At 12 months, forced expiratory volume in 1 second, forced vital capacity and 6MWD correlated significantly with multiple SF-36 domain scores. DLCO correlated significantly only with domain scores reflecting physical function. CONCLUSIONS: The mortality of SARS-related ARDS is similar to the mortality of ARDS from other causes. A substantial number of patients with SARS-related ARDS survived without receiving mechanical ventilation. Patients had good recovery of pulmonary function and HRQoL.

Adult↗
PubMed2005

Prognosis following Postanoxic Myoclonus Status epilepticus.

Prediction of outcome after cardiac arrest has important ethical and socioeconomic implications. In general, delay in recovery of neurological function is associated with a worse prognosis. The presence of myoclonic seizures early after anoxia has been identified as a poor prognostic factor. We report a series of patients who developed postanoxic myoclonus status epilepticus (MSE), which was defined as continuous myoclonic seizure activity lasting 30 min or more. The results from 18 patients were retrieved, 11 men and 7 women, age ranging from 29 to 90 years. Myoclonus developed a mean of 11.7 h after cardiac arrest, persisting for a mean of 60.5 h. Sixteen (89%) died following MSE and the 2 survivors were highly dependent or remained in a persistent vegetative state, supporting the view that prognosis is poor in this condition.

Adult↗
PubMed2004

Severe acute respiratory syndrome: correlation between clinical outcome and radiologic features.

PURPOSE: To evaluate whether there is a correlation between the clinical outcomes and radiologic features of severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: The clinical, laboratory, and radiologic features of 138 patients with SARS were analyzed. Three radiologists in consensus retrospectively assessed the frontal chest radiographs obtained at presentation and during treatment (n = 2045) for the distribution (each lung was divided into upper, middle, and lower zones) and extent of lung parenchymal abnormality. Clinical end points included intensive care unit (ICU) admission and death. RESULTS: Thirty-six (26.1%) patients required ICU care, and eight (5.8%) died. The patients who required ICU care and/or died had more extensive consolidation on chest radiographs obtained initially (median percentage of consolidation, 3.30%, with interquartile range [IR] of 1.70%-8.78% vs 1.70% [IR, 0%-3.30%]; P < .001) and on day 7 after fever onset (median percentage of consolidation, 15.00% [IR, 6.48%-28.73%] vs 5.00% [IR, 2.50%-7.50%]; P < .001) than did surviving patients who did not require ICU care. Patients with involvement of more than one lung zone on initial and day 7 chest radiographs were more likely to require ICU care and/or die than were those with involvement of one or fewer zones (P < .001). Patients with bilateral pneumonic changes at presentation were more likely to have an adverse outcome than were those with unilateral pneumonia (P < .001). Involvement of more than one lung zone at baseline chest radiography was an independent predictor of ICU admission and/or death (odds ratio, 3.16; 95% confidence interval: 1.07, 9.32; P = .037) after adjustments for other significant factors (ie, patient age, and baseline neutrophil count and lactate dehydrogenase level). CONCLUSION: More extensive airspace disease at presentation is an independent predictor of adverse outcome in patients with SARS.

Adult↗
PubMed2004

Increase in methicillin-resistant Staphylococcus aureus acquisition rate and change in pathogen pattern associated with an outbreak of severe acute respiratory syndrome.

BACKGROUND: An outbreak of severe acute respiratory syndrome (SARS) occurred in our 22-bed intensive care unit (ICU; Prince of Wales Hospital, Hong Kong, HKSAR, China) from 12 March to 31 May 2003, when only patients with SARS were admitted. This period was characterized by the upgrading of infection control precautions, which included the wearing of gloves and gowns all the time, an extensive use of steroids, and a change in antibiotic prescribing practices. The pattern of endemic pathogenic organisms, the rates of acquisition of methicillin-resistant Staphylococcus aureus (MRSA), and the rates of ventilator-associated pneumonia (VAP) were compared with those of the pre-SARS and post-SARS periods. METHODS: Data on pathogenic isolates were obtained from the microbiology department (Prince of Wales Hospital). Data on MRSA acquisition and VAP rates were collected prospectively. MRSA screening was performed for all ICU patients. A case of MRSA carriage was defined as an instance in which MRSA was recovered from any site in a patient, and cases were classified as imported or ICU-acquired if the first MRSA isolate was recovered within 72 h of ICU admission or after 72 h in the ICU, respectively. RESULTS: During the SARS period in the ICU, there was an increase in the rate of isolation of MRSA and Stenotrophomonas and Candida species but a disappearance of Pseudomonas and Klebsiella species. The MRSA acquisition rate was also increased: it was 3.53% (3.53 cases per 100 admissions) during the pre-SARS period, 25.30% during the SARS period, and 2.21% during the post-SARS period (P<.001). The VAP rate was high, at 36.5 episodes per 1000 ventilator-days, and 47% of episodes were caused by MRSA. CONCLUSIONS: A SARS outbreak in the ICU led to changes in the pathogen pattern and the MRSA acquisition rate. The data suggest that MRSA cross-transmission may be increased if gloves and gowns are worn all the time.

Anti-Bacterial Agents↗
PubMed2004

Short-term outcome of critically ill patients with severe acute respiratory syndrome.

OBJECTIVE: To document the outcome and determine prognostic factors for patients with severe acute respiratory syndrome who require admission to an intensive care unit. DESIGN: Observational cohort study involving retrospective analysis of demographic, clinical, laboratory and radiological data. SETTING: Adult intensive care unit in a tertiary referral university hospital involved in a major outbreak of severe acute respiratory syndrome (SARS). PATIENTS: The first 54 patients admitted with SARS to an intensive care unit (ICU). All were treated with corticosteroids, ribavirin, broad spectrum antimicrobials and supportive therapy. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: All patients were admitted for respiratory failure. The median APACHE II score was 11 (interquartile range 8-13). At 28 days 34 patients (63%; 95% CI 49.6-74.6) were alive and not mechanically ventilated. Six patients were alive but ventilated (11.3%; 95% confidence interval 5.3-22.6) and 14 had died (25.9%; CI 16.1-38.9). Seven of 27 ventilated patients developed evidence of barotrauma (25.9%; 95% CI 13.2-44.7). Median maximal multiple-organ dysfunction score was 5 (interquartile range 3.3-9). Median maximal respiratory dysfunction score was 3 (interquartile range 3-4). Increased age, severity of illness, lymphocyte count, decreased steroid dose, positive fluid balance, chronic disease or immunosuppression and nosocomial sepsis were associated with poor outcome on univariate analysis. Poor outcome was defined as death or need for mechanical ventilation at 28 days after ICU admission. CONCLUSIONS: Mortality amongst critically ill patients with SARS is high. It causes predominantly severe respiratory failure, with little other organ failure, and a high incidence of barotrauma amongst those requiring mechanical ventilation.

Adult↗
PubMed2004

The effect of adsorption, filter material and point of dilution on antibiotic elimination by haemofiltration an in vitro study of levofloxacin.

We studied an in vitro model of continuous venous-venous haemofiltration (CVVH), into which levofloxacin 100 mg was infused, to determine levofloxacin adsorption and to determine the effect of filter material and point of dilution (pre- or post-filter) on sieving coefficient. Mean (standard deviation; S.D.) adsorption was 18.7 (5.3) mg for the polyamide filter and 40.2 (2.0) mg for the polyacrylonitrile (PAN) filter (P < 0.001). Post-dilution resulted in a minor, but statistically significant, decrease in sieving coefficient (pre-dilution 0.96 (S.D. 0.10), post-dilution 0.88 (S.D. 0.11) with the PAN filter. These data indicate that the variability in published values for levofloxacin sieving coefficient are not due to variation in point of dilution or membrane type (PAN or polyamide). Significant adsorption of levofloxacin onto PAN filters occurs.

Hemodiafiltration↗
PubMed2004

Limitation of life support: frequency and practice in a Hong Kong intensive care unit.

OBJECTIVE: To examine the frequency and the decision-making processes involved in limiting (withdrawing and withholding) life support therapy in critically ill Chinese patients in the intensive care unit. DESIGN: Prospective survey of patients who had life support limited between April 1997 and March 1999. SETTING: Medical and surgical intensive care unit of a teaching hospital. PATIENTS: All patients admitted to the intensive care unit of the Prince of Wales Hospital who subsequently died and/or had life support limited. Brain-dead patients were excluded from analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 490 patients who died in the intensive care unit, limitation of life support occurred in 288 (58.8%). Relatives or patients requested limitation of life support in 32 cases (11%). The family and/or patient concurred with limitation of life support in 273 occasions (95%). Therapy was withheld in 30.8% and withdrawn in 28.0% of deaths. Therapy limited included inotropes, additional oxygen, and renal replacement therapy. CONCLUSIONS: Limitation of therapy in dying Chinese patients occurs frequently in intensive care patients, and both patients and relatives concur with medical decisions to limit therapy in these patients. Withholding therapy rather than withdrawing therapy occurs more frequently than in Western populations.

Female↗
PubMed2004

Late-stage adult respiratory distress syndrome caused by severe acute respiratory syndrome: abnormal findings at thin-section CT.

PURPOSE: To evaluate thin-section computed tomographic (CT) abnormalities in patients in the intensive care unit during the late stage of adult respiratory distress syndrome (ARDS) caused by severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Eight patients in the late stage of ARDS (ie, more than 2 weeks after onset) were imaged with thin-section CT. Images were evaluated for ground-glass opacification, consolidation, interstitial thickening, evidence of fibrosis, and any other abnormalities. Patient records were reviewed, and relevant respiratory and ventilatory parameters, total steroid dose, and outcome were recorded. RESULTS: All patients received high-dose pulse methylprednisolone (minimum, 2.5 g total), and all patients who received ventilation received low-pressure, low-volume ventilation. Five patients received prolonged mechanical ventilation (for more than 14 days), one received ventilation for 72 hours, and two patients did not receive ventilation. Three patients died, four were discharged from the hospital, and one continued to require ventilation. Ground-glass opacification and interstitial thickening were present at CT in all eight patients. Consolidation was present in six patients. Three patients had evidence of fibrosis. Patients who received long-term ventilation, those who received short-term ventilation, and those who did not receive ventilation had similar pulmonary changes at CT. Pulmonary cysts, most of which were small (<1 cm), were present in five patients. Cysts were present in one patient who received only short-term low-pressure and low-volume ventilation and in one patient who received no mechanical ventilation. CONCLUSION: The CT features of late-stage ARDS caused by SARS are similar to those seen in late-stage ARDS of other causes, with no apparent differences between patients who do and patients who do not receive prolonged mechanical ventilation. The presence of cysts in one patient who received short-term and one patient who received no mechanical ventilation suggests that severe SARS-induced ARDS may independently result in cyst formation.

Adult↗
PubMed2003

A major outbreak of severe acute respiratory syndrome in Hong Kong.

BACKGROUND: There has been an outbreak of the severe acute respiratory syndrome (SARS) worldwide. We report the clinical, laboratory, and radiologic features of 138 cases of suspected SARS during a hospital outbreak in Hong Kong. METHODS: From March 11 to 25, 2003, all patients with suspected SARS after exposure to an index patient or ward were admitted to the isolation wards of the Prince of Wales Hospital. Their demographic, clinical, laboratory, and radiologic characteristics were analyzed. Clinical end points included the need for intensive care and death. Univariate and multivariate analyses were performed. RESULTS: There were 66 male patients and 72 female patients in this cohort, 69 of whom were health care workers. The most common symptoms included fever (in 100 percent of the patients); chills, rigors, or both (73.2 percent); and myalgia (60.9 percent). Cough and headache were also reported in more than 50 percent of the patients. Other common findings were lymphopenia (in 69.6 percent), thrombocytopenia (44.8 percent), and elevated lactate dehydrogenase and creatine kinase levels (71.0 percent and 32.1 percent, respectively). Peripheral air-space consolidation was commonly observed on thoracic computed tomographic scanning. A total of 32 patients (23.2 percent) were admitted to the intensive care unit; 5 patients died, all of whom had coexisting conditions. In a multivariate analysis, the independent predictors of an adverse outcome were advanced age (odds ratio per decade of life, 1.80; 95 percent confidence interval, 1.16 to 2.81; P=0.009), a high peak lactate dehydrogenase level (odds ratio per 100 U per liter, 2.09; 95 percent confidence interval, 1.28 to 3.42; P=0.003), and an absolute neutrophil count that exceeded the upper limit of the normal range on presentation (odds ratio, 1.60; 95 percent confidence interval, 1.03 to 2.50; P=0.04). CONCLUSIONS: SARS is a serious respiratory illness that led to significant morbidity and mortality in our cohort.

Adult↗