Reasonable Rascal
10-16-09, 12:29
Read the conclusion at the end. it tends to run somewhat counter to what the mainstream media is reporting here. RR
INFLUENZA PANDEMIC (H1N1) 2009 (69): CASE MANAGEMENT
************************************************** **
A ProMED-mail post
In this update:
[1] ECMO (Australia and New Zealand)
[2] Canadian experience
******
[1] ECMO (Australia and New Zealand)
Date: Tue 13 Oct 2009
Source: ABC Science [edited]
<http://www.abc.net.au/science/articles/2009/10/13/2711206.htm>
Oxygen treatment key to swine flu survival
------------------------------------------
A new Australian and New Zealand study, published in today's edition of the Journal of the American Medical Association [JAMA], found that 79 per cent of swine flu patients treated with extracorporeal membrane oxygenation (ECMO) survived. Intensive care specialist Dr Daryl Jones of Monash University in Melbourne, says ECMO is an artificial heart and lung machine. It takes the blood out of the body, removes the carbon dioxide and replaces it with oxygen and then sends the blood back in and around the body, he says.
The study collected data on swine flu [influenza pandemic (H1N1) 2009 virus infection] patients from all 15 centres that offer ECMO treatment in Australia and New Zealand. Of the 5000 people infected with swine flu in Australia and New Zealand that needed hospitalisation, 61 required treatment with ECMO, he says. Jones says that's a significant increase on the amount of people who've required ECMO in the past. "Last year only 4 patients across Australia and New Zealand required ECMO during winter."
Jones says that, unlike seasonal influenza, swine flu has affected many young adults. "A substantial number of young people became very sick with pneumonia [due to] the virus or a secondary infection," he says. According to Jones, when patients become very short of breath and have respiratory failure, they're put on a ventilator. If that doesn't work, ECMO treatment is the last resort.
Paediatrician Professor Robert Booy, of the Children's Hospital at Westmead in Sydney, says patients that require ECMO are "extremely unwell and teetering on death". Of the 61 swine flu patients treated with ECMO, 79 per cent survived, which Booy says is "very impressive". Without ECMO, about 90 per cent of people suffering from severe influenza associated respiratory failure would have died, he says. But Booy says the current swine flu death rate statistics in Australia are "hiding" those saved from intensive care management. "When we say we've had just under 200 deaths, the numbers could easily have been twice that, but for the fact we've got such high quality intensive care in Australia and New Zealand."
Booy says the study is extremely important, and demonstrates that intensive care doctors across Australia and New Zealand have a "superb" network, which allows them to publish important research quickly. Jones admits the study was unable to determine the survival rate of those with severe respiratory failure associated with swine flu who did not receive ECMO treatment.
He says Australian clinicians were "forewarned" of what to expect before swine flue arrived in Australia, by the experiences of doctors in Mexico and the US. When the outbreak of swine flu was announced in Mexico, he says a lot of young people were presenting with severe pneumonia. "They also reported a very high fatality rate per case of infection." Jones hopes their study will be of similar value to the Northern Hemisphere who have yet to experience swine flu outbreaks during winter. "Given what we learned from the Mexican experience, we felt we had an obligation to reciprocally provide advanced warning for people in the north."
An editorial also published in the latest edition of JAMA written by Dr Douglas White and Dr Derek Angus, both of the University of Pittsburgh, says any deaths from swine flu will be regrettable. "But those that result from insufficient planning and inadequate preparation will be especially tragic."
--
communicated by:
ProMED-mail rapporteur Mary Marshall
[The interactive HealthMap/ProMED map of Australia is available at
<http://healthmap.org/r/00cS>. The interactive HealthMap/ProMED map of New Zealand is available at <http://healthmap.org/r/00c3> - CopyEd.EJP]
******
[2] Canadian experience
Date: Mon 12 Oct 2009
Source: CBC Health [edited]
<http://www.cbc.ca/health/story/2009/10/12/h1n1-virus-infection-females-young-aboriginals-study.html>
Severe H1N1 infection in females "striking"
-------------------------------------------
Many of the Canadians who died or were sent to hospital earlier this year [2009] with H1N1 virus [influenza pandemic (H1N1) 2009 virus] were young adults, female and aboriginal, a new study suggests. The study, published in Monday's online issue of JAMA, looked at 168 patients with confirmed or probable swine flu. Of the group, 24 or 14.3 per cent, died within the first 28 days of becoming critically ill, Dr Anand Kumar, an intensive care specialist at the Health Sciences Centre and St. Boniface Hospital in Winnipeg and his colleagues found. "Our data suggest that severe disease and mortality in the current outbreak is concentrated in relatively healthy adolescents and adults between the ages of 10 and 60 years," the study's authors wrote. The ages in the mortality pattern were similar to that of the 1918 H1N1 Spanish flu pandemic, they said.
--
communicated by:
ProMED-mail rapporteur Mary Marshall
[To put thee findings in perspective the commentary of the authors of the JAMA paper referred to above
(<http://jama.ama-assn.org/cgi/content/full/2009.1496>) is reproduced
below. - Mod.CP
"The spring outbreak of influenza A(H1N1) 2009 virus infection in Canada affected primarily young, female, and aboriginal patients without major co-morbidities, and conferred a 28-day mortality of 14.3 per cent among critically ill patients. A history of lung disease or smoking, obesity, hypertension, and diabetes were the most common co-morbidities. Critical illness occurred rapidly after hospital admission and was associated with severe oxygenation failure, a requirement for prolonged mechanical ventilation, and the frequent use of rescue therapies.
"We identified unusual features of severe disease in the current pandemic compared with most previous well-characterized pandemics, including the (probable) H2N2 1890 Russian influenza pandemic, the H2N2 1957 Asian influenza pandemic, and the H3N2 1968 Hong Kong pandemic. In these previous influenza pandemics, an increased predilection for infection among children and young adults has been documented, although mortality curves were U-shaped with increased deaths in the very young and the aged.
"Our data suggest that severe disease and mortality in the current outbreak is concentrated in relatively healthy adolescents and adults between the ages of 10 and 60 years, a pattern reminiscent of the W-shaped curve previously seen only during the 1918 H1N1 Spanish pandemic. Few patients older than 60 years in this study were admitted to the ICU. A potential biological basis for this observation is that patients in this age group have a cross-reactive antibody to 2009 influenza A (H1N1) at much higher rates than younger patients.
"The increased fraction of the aboriginal community presenting with severe influenza A (H1N1) 2009 infection is notable but not unique. This finding is reflected in the history of the 1918 H1N1 Spanish influenza pandemic during which mortality in aboriginal communities in North America (3 per cent to 9 per cent) was many times higher than nonaboriginal communities (generally <0.75 per cent). In 1918, mortality within Alaskan and Labrador Inuit populations was 30 per cent to 90 per cent. Although mortality was not substantially greater among aboriginal Canadians in this report, the number of patients with severe disease and knowledge of prior illness patterns in this community is cause for concern.
"The tendency of females to develop severe influenza A(H1N1) 2009 virus infection in this series is striking. A general female susceptibility has not been observed in other influenza case series of variable severity including the initial reports of influenza A (H1N1) 2009 virus infections. In most infectious diseases and related conditions such as sepsis and septic shock, males represent a larger proportion of cases and have a higher mortality. The explanation for increased risk of severe disease and death among females in this report is unclear but the role of pregnancy as a risk factor has been noted in previous influenza pandemics.
"The most common comorbidities among critically ill patients in our study were lung disease, obesity, hypertension, and a history of smoking or diabetes, each occurring in 30 per cent to 40 per cent of patients. All these conditions are known to be increased in frequency in the aboriginal population that comprises a substantial portion of cases within this cohort. The extent to which these comorbidities contribute to severity of disease is unclear because a large portion of the aboriginal population (which may be a risk factor itself on the basis of genetic susceptibility) often have such comorbidities.
"Among critically ill patients, obesity has been shown to be a risk factor for increased morbidity, but not consistently with mortality. The association of obesity with severe influenza A(H1N1) 2009 virus infection has been reported by others and may be a novel finding of this pandemic; however, even though obesity was more common in our series than in the general Canadian population (33 per cent versus approximately 24 per cent), we did not find a significant difference in BMI between survivors and nonsurvivors.
"Critically ill patients with diabetes and hyperglycemia also are known to be at increased risk of complications and death; similarly, alcohol abuse, which is known to be a risk factor for acute respiratory distress syndrome, may have been a risk factor some patients in our series. These relationships also have been reported with seasonal influenza. The relative absence of serious co-morbidities emphasizes that young, relatively healthy adults were the primary population affected by severe influenza A(H1N1) 2009 infection during this outbreak.
"Patients with influenza A (H1N1) 2009 virus infection-related critical illness experienced symptoms for an average of 4 days prior to hospital presentation, but rapidly worsened and required care in the ICU within 1 to 2 days. Apart from the usual symptoms seen in seasonal influenza, these cases stand out for the presence of gastrointestinal tract symptoms, dyspnea, purulent sputum production, and occasional frothy lung fluid on cough or endotracheal aspiration. Chest radiographs demonstrating bilateral mixed interstitial or alveolar infiltrates were found in three-quarters of the patients.
"Approximately one-third of patients required vasopressor support on day 1 following ICU admission; however, in many cases this appeared temporally associated with the need for substantial sedation to optimize ventilation. Broad-spectrum antibacterial agents were initiated in almost all patients because of the initial suspicion of community-acquired bacterial pneumonia. However, actual bacterial lung infection was typically documented later in the course of critical illness.
"In addition, approximately one-third of patients in our cohort required advanced ventilatory support and rescue therapies for profound hypoxemic respiratory failure, including high levels of inspired oxygen and PEEP, pressure control, and airway pressure release ventilation, high-frequency oscillatory ventilation, prone positioning ventilation, neuromuscular blockade, inhaled nitric oxide, and extracorporeal membrane oxygenation [ECMO]. The fact that severe illness arises in a young, previously healthy population with a high probability of survival given the availability of appropriate resources has important societal implications.
"In Winnipeg, Manitoba, Canada, site of the largest pandemic cohort of patients, the capacity for the care of critically ill patients was seriously challenged at the outbreak peak in June with full occupancy of all regional ICU beds, similar to the 2002 Toronto, Ontario, Canada, experience with severe acute respiratory syndrome. If, as expected, the prevalence of influenza A (H1N1) 2009 virus infection increases with the upcoming flu season, there will be an acutely increased demand for ICU care, including the need for rescue therapies that are not currently widely available. Clinicians and policy makers will need to examine feasible methods to optimally expand and deploy ICU resources to meet this need.
"This study has a number of strengths. It represents the largest series of patients with severe influenza A (H1N1) 2009 infection yet described, and includes both adults and children from geographically and racially diverse settings across Canada, which improves the generalizability of our results to other regions. These observations of the epidemiological risk factors, typical clinical features, response to therapy, and prognosis should aid in the recognition, diagnosis, and clinical management of such infections. Our finding that patients can often be supported through 2009 influenza A (H1N1) infectionrelated critical illness with prolonged, aggressive life support, and the expectation that the number of cases will likely increase substantially over the next 6 months, highlight important potential limitations in critical care capacity.
"This study also has limitations. Our focus on severe disease requiring ICU admission may not reflect important presenting features in less severe cases. The ongoing deaths throughout the course of the study period suggest the possibility of late deaths after the observation period. This may result in a final hospital mortality rate that exceeds the mortality rate we are reporting. Although we describe cases in most regions of Canada, many were from an outbreak in a single province (Manitoba) and involved an aboriginal Canadian population near Winnipeg, which is Manitoba's largest city. This may lead to overrepresentation or underrepresentation of certain comorbidities and clinical features.
[B]"In conclusion, we have demonstrated that 2009 influenza A(H1N1) infection-related critical illness predominantly affects young patients with few major comorbidities and is associated with severe hypoxemic respiratory failure, often requiring prolonged mechanical ventilation and rescue therapies. With such therapy, we found that most patients can be supported through their critical illness." - Mod.CP Emphasis mine. RR
The interactive HealthMap/ProMED map of Canada is available at
<http://healthmap.org/r/007x> - CopyEd.EJP]
INFLUENZA PANDEMIC (H1N1) 2009 (69): CASE MANAGEMENT
************************************************** **
A ProMED-mail post
In this update:
[1] ECMO (Australia and New Zealand)
[2] Canadian experience
******
[1] ECMO (Australia and New Zealand)
Date: Tue 13 Oct 2009
Source: ABC Science [edited]
<http://www.abc.net.au/science/articles/2009/10/13/2711206.htm>
Oxygen treatment key to swine flu survival
------------------------------------------
A new Australian and New Zealand study, published in today's edition of the Journal of the American Medical Association [JAMA], found that 79 per cent of swine flu patients treated with extracorporeal membrane oxygenation (ECMO) survived. Intensive care specialist Dr Daryl Jones of Monash University in Melbourne, says ECMO is an artificial heart and lung machine. It takes the blood out of the body, removes the carbon dioxide and replaces it with oxygen and then sends the blood back in and around the body, he says.
The study collected data on swine flu [influenza pandemic (H1N1) 2009 virus infection] patients from all 15 centres that offer ECMO treatment in Australia and New Zealand. Of the 5000 people infected with swine flu in Australia and New Zealand that needed hospitalisation, 61 required treatment with ECMO, he says. Jones says that's a significant increase on the amount of people who've required ECMO in the past. "Last year only 4 patients across Australia and New Zealand required ECMO during winter."
Jones says that, unlike seasonal influenza, swine flu has affected many young adults. "A substantial number of young people became very sick with pneumonia [due to] the virus or a secondary infection," he says. According to Jones, when patients become very short of breath and have respiratory failure, they're put on a ventilator. If that doesn't work, ECMO treatment is the last resort.
Paediatrician Professor Robert Booy, of the Children's Hospital at Westmead in Sydney, says patients that require ECMO are "extremely unwell and teetering on death". Of the 61 swine flu patients treated with ECMO, 79 per cent survived, which Booy says is "very impressive". Without ECMO, about 90 per cent of people suffering from severe influenza associated respiratory failure would have died, he says. But Booy says the current swine flu death rate statistics in Australia are "hiding" those saved from intensive care management. "When we say we've had just under 200 deaths, the numbers could easily have been twice that, but for the fact we've got such high quality intensive care in Australia and New Zealand."
Booy says the study is extremely important, and demonstrates that intensive care doctors across Australia and New Zealand have a "superb" network, which allows them to publish important research quickly. Jones admits the study was unable to determine the survival rate of those with severe respiratory failure associated with swine flu who did not receive ECMO treatment.
He says Australian clinicians were "forewarned" of what to expect before swine flue arrived in Australia, by the experiences of doctors in Mexico and the US. When the outbreak of swine flu was announced in Mexico, he says a lot of young people were presenting with severe pneumonia. "They also reported a very high fatality rate per case of infection." Jones hopes their study will be of similar value to the Northern Hemisphere who have yet to experience swine flu outbreaks during winter. "Given what we learned from the Mexican experience, we felt we had an obligation to reciprocally provide advanced warning for people in the north."
An editorial also published in the latest edition of JAMA written by Dr Douglas White and Dr Derek Angus, both of the University of Pittsburgh, says any deaths from swine flu will be regrettable. "But those that result from insufficient planning and inadequate preparation will be especially tragic."
--
communicated by:
ProMED-mail rapporteur Mary Marshall
[The interactive HealthMap/ProMED map of Australia is available at
<http://healthmap.org/r/00cS>. The interactive HealthMap/ProMED map of New Zealand is available at <http://healthmap.org/r/00c3> - CopyEd.EJP]
******
[2] Canadian experience
Date: Mon 12 Oct 2009
Source: CBC Health [edited]
<http://www.cbc.ca/health/story/2009/10/12/h1n1-virus-infection-females-young-aboriginals-study.html>
Severe H1N1 infection in females "striking"
-------------------------------------------
Many of the Canadians who died or were sent to hospital earlier this year [2009] with H1N1 virus [influenza pandemic (H1N1) 2009 virus] were young adults, female and aboriginal, a new study suggests. The study, published in Monday's online issue of JAMA, looked at 168 patients with confirmed or probable swine flu. Of the group, 24 or 14.3 per cent, died within the first 28 days of becoming critically ill, Dr Anand Kumar, an intensive care specialist at the Health Sciences Centre and St. Boniface Hospital in Winnipeg and his colleagues found. "Our data suggest that severe disease and mortality in the current outbreak is concentrated in relatively healthy adolescents and adults between the ages of 10 and 60 years," the study's authors wrote. The ages in the mortality pattern were similar to that of the 1918 H1N1 Spanish flu pandemic, they said.
--
communicated by:
ProMED-mail rapporteur Mary Marshall
[To put thee findings in perspective the commentary of the authors of the JAMA paper referred to above
(<http://jama.ama-assn.org/cgi/content/full/2009.1496>) is reproduced
below. - Mod.CP
"The spring outbreak of influenza A(H1N1) 2009 virus infection in Canada affected primarily young, female, and aboriginal patients without major co-morbidities, and conferred a 28-day mortality of 14.3 per cent among critically ill patients. A history of lung disease or smoking, obesity, hypertension, and diabetes were the most common co-morbidities. Critical illness occurred rapidly after hospital admission and was associated with severe oxygenation failure, a requirement for prolonged mechanical ventilation, and the frequent use of rescue therapies.
"We identified unusual features of severe disease in the current pandemic compared with most previous well-characterized pandemics, including the (probable) H2N2 1890 Russian influenza pandemic, the H2N2 1957 Asian influenza pandemic, and the H3N2 1968 Hong Kong pandemic. In these previous influenza pandemics, an increased predilection for infection among children and young adults has been documented, although mortality curves were U-shaped with increased deaths in the very young and the aged.
"Our data suggest that severe disease and mortality in the current outbreak is concentrated in relatively healthy adolescents and adults between the ages of 10 and 60 years, a pattern reminiscent of the W-shaped curve previously seen only during the 1918 H1N1 Spanish pandemic. Few patients older than 60 years in this study were admitted to the ICU. A potential biological basis for this observation is that patients in this age group have a cross-reactive antibody to 2009 influenza A (H1N1) at much higher rates than younger patients.
"The increased fraction of the aboriginal community presenting with severe influenza A (H1N1) 2009 infection is notable but not unique. This finding is reflected in the history of the 1918 H1N1 Spanish influenza pandemic during which mortality in aboriginal communities in North America (3 per cent to 9 per cent) was many times higher than nonaboriginal communities (generally <0.75 per cent). In 1918, mortality within Alaskan and Labrador Inuit populations was 30 per cent to 90 per cent. Although mortality was not substantially greater among aboriginal Canadians in this report, the number of patients with severe disease and knowledge of prior illness patterns in this community is cause for concern.
"The tendency of females to develop severe influenza A(H1N1) 2009 virus infection in this series is striking. A general female susceptibility has not been observed in other influenza case series of variable severity including the initial reports of influenza A (H1N1) 2009 virus infections. In most infectious diseases and related conditions such as sepsis and septic shock, males represent a larger proportion of cases and have a higher mortality. The explanation for increased risk of severe disease and death among females in this report is unclear but the role of pregnancy as a risk factor has been noted in previous influenza pandemics.
"The most common comorbidities among critically ill patients in our study were lung disease, obesity, hypertension, and a history of smoking or diabetes, each occurring in 30 per cent to 40 per cent of patients. All these conditions are known to be increased in frequency in the aboriginal population that comprises a substantial portion of cases within this cohort. The extent to which these comorbidities contribute to severity of disease is unclear because a large portion of the aboriginal population (which may be a risk factor itself on the basis of genetic susceptibility) often have such comorbidities.
"Among critically ill patients, obesity has been shown to be a risk factor for increased morbidity, but not consistently with mortality. The association of obesity with severe influenza A(H1N1) 2009 virus infection has been reported by others and may be a novel finding of this pandemic; however, even though obesity was more common in our series than in the general Canadian population (33 per cent versus approximately 24 per cent), we did not find a significant difference in BMI between survivors and nonsurvivors.
"Critically ill patients with diabetes and hyperglycemia also are known to be at increased risk of complications and death; similarly, alcohol abuse, which is known to be a risk factor for acute respiratory distress syndrome, may have been a risk factor some patients in our series. These relationships also have been reported with seasonal influenza. The relative absence of serious co-morbidities emphasizes that young, relatively healthy adults were the primary population affected by severe influenza A(H1N1) 2009 infection during this outbreak.
"Patients with influenza A (H1N1) 2009 virus infection-related critical illness experienced symptoms for an average of 4 days prior to hospital presentation, but rapidly worsened and required care in the ICU within 1 to 2 days. Apart from the usual symptoms seen in seasonal influenza, these cases stand out for the presence of gastrointestinal tract symptoms, dyspnea, purulent sputum production, and occasional frothy lung fluid on cough or endotracheal aspiration. Chest radiographs demonstrating bilateral mixed interstitial or alveolar infiltrates were found in three-quarters of the patients.
"Approximately one-third of patients required vasopressor support on day 1 following ICU admission; however, in many cases this appeared temporally associated with the need for substantial sedation to optimize ventilation. Broad-spectrum antibacterial agents were initiated in almost all patients because of the initial suspicion of community-acquired bacterial pneumonia. However, actual bacterial lung infection was typically documented later in the course of critical illness.
"In addition, approximately one-third of patients in our cohort required advanced ventilatory support and rescue therapies for profound hypoxemic respiratory failure, including high levels of inspired oxygen and PEEP, pressure control, and airway pressure release ventilation, high-frequency oscillatory ventilation, prone positioning ventilation, neuromuscular blockade, inhaled nitric oxide, and extracorporeal membrane oxygenation [ECMO]. The fact that severe illness arises in a young, previously healthy population with a high probability of survival given the availability of appropriate resources has important societal implications.
"In Winnipeg, Manitoba, Canada, site of the largest pandemic cohort of patients, the capacity for the care of critically ill patients was seriously challenged at the outbreak peak in June with full occupancy of all regional ICU beds, similar to the 2002 Toronto, Ontario, Canada, experience with severe acute respiratory syndrome. If, as expected, the prevalence of influenza A (H1N1) 2009 virus infection increases with the upcoming flu season, there will be an acutely increased demand for ICU care, including the need for rescue therapies that are not currently widely available. Clinicians and policy makers will need to examine feasible methods to optimally expand and deploy ICU resources to meet this need.
"This study has a number of strengths. It represents the largest series of patients with severe influenza A (H1N1) 2009 infection yet described, and includes both adults and children from geographically and racially diverse settings across Canada, which improves the generalizability of our results to other regions. These observations of the epidemiological risk factors, typical clinical features, response to therapy, and prognosis should aid in the recognition, diagnosis, and clinical management of such infections. Our finding that patients can often be supported through 2009 influenza A (H1N1) infectionrelated critical illness with prolonged, aggressive life support, and the expectation that the number of cases will likely increase substantially over the next 6 months, highlight important potential limitations in critical care capacity.
"This study also has limitations. Our focus on severe disease requiring ICU admission may not reflect important presenting features in less severe cases. The ongoing deaths throughout the course of the study period suggest the possibility of late deaths after the observation period. This may result in a final hospital mortality rate that exceeds the mortality rate we are reporting. Although we describe cases in most regions of Canada, many were from an outbreak in a single province (Manitoba) and involved an aboriginal Canadian population near Winnipeg, which is Manitoba's largest city. This may lead to overrepresentation or underrepresentation of certain comorbidities and clinical features.
[B]"In conclusion, we have demonstrated that 2009 influenza A(H1N1) infection-related critical illness predominantly affects young patients with few major comorbidities and is associated with severe hypoxemic respiratory failure, often requiring prolonged mechanical ventilation and rescue therapies. With such therapy, we found that most patients can be supported through their critical illness." - Mod.CP Emphasis mine. RR
The interactive HealthMap/ProMED map of Canada is available at
<http://healthmap.org/r/007x> - CopyEd.EJP]