News In Brief
Patients with anaemia that undergo a range of non-cardiac surgical procedures have a 42% increased risk of death and a 35% increased risk of serious comorbidities compared with patients who are not anaemic. The findings are reported in an article published Online First and in the upcoming Surgery Special Issue of The Lancet, written by Dr Khaled M Musallam and Dr Faek R Jamali, American University of Beirut Medical Center, Beirut, Lebanon, and colleagues.
Preoperative anaemia is known to be associated with adverse outcomes after cardiac surgery but outcomes after non-cardiac surgery are not well established. In this study, the authors aimed to assess the effect of preoperative anaemia on 30-day postoperative morbidity and mortality in patients undergoing major non-cardiac surgery, by analysing a large dataset from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP).
The types of surgery covered by the study were general, vascular, orthopaedic, gynaecological, urological, neurosurgical, otolaryngological, plastic, and thoracic. The data included postoperative outcomes of death, and major morbidities including cardiac, respiratory, CNS, urinary tract, wound, sepsis, and venous thromboembolism, as well as demographics, and preoperative and perioperative risk factors.
Data from 227,425 patients was assessed, of whom 69,229 (30%) had preoperative anaemia. Postoperative mortality at 30 days was 42% higher in patients with anaemia than in those without anaemia. This increased risk was consistent for mild anaemia (41%) and moderate-to-severe anaemia (44%). Patients with anaemia were also 35% more likely to have postoperative morbidities (for example cardiac, respiratory, urinary, wound, sepsis and thromboembolic problems) than in those without anaemia, again both in patients with mild anaemia (31% increased risk) and moderate-to-severe anaemia (56% increased risk). When compared with patients without anaemia or a defined risk factor, patients with anaemia and most risk factors (for example age =65 years, cardiac disease, severe chronic obstructive pulmonary disease, CNS disease, renal disease, cancer, or systemic sepsis) had a higher adjusted risk for 30-day mortality and morbidity than did patients with either anaemia or the risk factor.
The authors conclude: “Because even mild anaemia increases the risk of postoperative morbidity and mortality in patients undergoing major non-cardiac surgery, doctors need to consider preoperative treatment of anaemia when possible. Further research is needed to establish the efficacy, safety, and cost-effectiveness of such preoperative anaemia management.”
In a linked Comment, Professor Hans Gombotz, Department of Anaesthesiology and Intensive Care, General Hospital Linz, Austria, says that, in some patients, there are risks associated with anaemia treatments such as iron supplementation or stimulation of red blood cell production (erythropoeisis).
However he concludes: “The study strongly indicates that the implementation of treatment of anaemia as part of a universal patient blood management should become standard of care in patients undergoing elective surgical procedures, particularly in those where substantial blood loss is to be expected.
“However, additional studies are urgently needed to secure the efficacy and safety of preoperative treatment of anaemia.”
News Items
Can blood type determine risk after heart surgery?
A new study presented at Anesthesiology 2011 focused on whether blood type affects survival after heart surgery. Researchers from Duke University Medical Center studied more than 15,000 patients to determine if a specific blood type puts patients at a higher risk for death or complications after coronary artery bypass graft (CABG) surgery.
The Duke researchers found that patients with AB blood type were 20 percent less likely to die after CABG surgery than patients with A, B or O blood types. Two proteins in the blood responsible for clotting – the von Willebrand factor (vWF) and Factor VIII (FVIII) –could explain the reduced risk.
The gene that passes on group O confers lower levels of these clotting proteins. Each person has two genes (one from each parent) to determine blood group; all group O patients have two O genes (OO). Some group A and group B patients have one group A or B and one group O gene (AO and BO) and have intermediate levels of clotting proteins. Group AB has no O genes and has the highest levels of the proteins.
Individuals with type O blood (nearly half of the population) have lower levels of these clotting proteins and may be at greater risk for bleeding and blood transfusions after surgery. Evidence suggests that individuals with type AB blood may be more likely to develop blood clots and/or bleed less after surgery, said lead study author Ian J. Welsby, M.D. However, blood clots do not appear to be a problem and bleeding less could contribute to the lower death rate in AB blood type patients since bleeding and blood transfusions put patients at a higher risk for death or complications after surgery.
The study concluded that AB patients are at lowest risk for bleeding and that further research is required to determine the order of risk in other blood types (A, B and O groups).
Researchers hope future studies will help with the ability to predict risk levels for bleeding after cardiac surgery using a simple, cheap blood group test. Researchers also want to determine whether boosting the vWF level in non-AB patients to the level found in AB patients will result in better outcomes after heart surgery.
New pain treatment plan for women who have caesarean delivery
Nearly one third of children in the U.S. are born by caesarean delivery, a surgery that puts women at risk for persistent pain and postpartum depression. A new study presented at Anesthesiology 2011 investigated whether an increase in pain treatment in patients at high risk for severe pain after surgery reduces these complications after a caesarean delivery.
Researchers at Wake Forest University School of Medicine preoperatively administered a questionnaire to women scheduled for a pre-planned, non-emergent caesarean delivery to help identify those at risk for severe pain after surgery.
Fifty-three participants who were expected to have severe pain after caesarean delivery, based on a simple questionnaire, were randomly selected to either receive a standard dose of long acting spinal morphine plus oral placebo tablets or a higher dose of long acting spinal morphine plus oral acetaminophen tablets. In addition, all patients received oral ibuprofen and intravenous morphine through a patient controlled pump.
Participants were assessed 24 hours after surgery for pain and at two months for chronic pain and postpartum depression. Findings showed that patients who received the larger dose of spinal morphine plus oral acetaminophen had significantly lower pain scores in the first 24 hours after a caesarean delivery than patients in the other treatment group without an increase in side effects. However, postpartum depression and pain two months later was not different between the groups.
“Through the use of a very brief questionnaire, we were able to identify which women were at high risk for severe pain after a caesarean delivery,” said lead study author Jessica L. Booth, M.D. “We were then able to tailor a postoperative pain treatment plan for these women using simple methods to improve the amount of pain in the days following this major abdominal operation.”
Less invasive anaesthetic methods better for endovascular aneurysm repair
A new study done by investigators at Wake Forest Baptist Medical Center found that using less invasive spinal, epidural and local/monitored anaesthesia care (MAC) is better than general anaesthesia for elective endovascular repair of infrarenal abdominal aortic aneurysms (EVAR).
Details of the research appear in the November issue of the Journal of Vascular Surgery, the official publication of the Society for Vascular Surgery.
Infrarenal abdominal aortic aneurysms make up about 95 percent or more of abdominal aortic aneurysms and, while they occur in both sexes, they are most prevalent in men older than 60, affecting about 3 percent of this population, explained study co-author
Matthew S. Edwards, B.A., M.S., M.D., a professor of vascular and endovascular surgery and public health sciences at Wake Forest Baptist.
“That’s a lot of people,” Edwards said. “If aortic aneurysms aren’t repaired, they can burst and 80 to 90 percent of people who have a ruptured aortic aneurysm die. It’s necessary for those who are suitable candidates for surgery to have their aneurysms repaired.”
EVAR has completely revolutionised the care of aneurysms, allowing doctors to do repairs through two small incisions in the groin, Edwards said. It is currently the most common procedure for repairing aortic aneurysms in the United States. Historic trends have led to general anaesthesia being the most common mode of anaesthesia used for this procedure, but it is sometimes associated with the development of pneumonia, the need for a breathing tube and other pulmonary complications, he explained.
Other anaesthetic techniques can also be used, such as local anaesthesia, local anaesthesia plus sedation (called “monitored” or “MAC”), spinal anaesthesia and epidural anaesthesia. According to this study, these other methods result in a shortened hospital stay and fewer pulmonary complications.
“In our study, general anaesthesia was associated with increased postoperative length of stay (LOS) and increased complications involving the lungs when compared to the other anaesthetic methods,” Edwards said.
The researchers collected data on 6,009 patients who had elective EVAR performed between 2005 to 2008 at one of 221 North American hospitals. General anaesthesia was used in 4,868 of the cases, while 419 patients had spinal anaesthesia during their procedure; 331 had epidural anaesthesia; and 391 had local/MAC. Any emergency cases and any patients who had other procedures being done at the same time that required general anaesthesia were excluded from the study.
The team then reviewed the data to evaluate rates of mortality, morbidity and length of stay (LOS), or how long the patient remained in the hospital after the procedure.
The researchers found that general anaesthesia was associated with an increase in pulmonary complications when compared to spinal and local/MAC anaesthesia. The use of general anaesthesia was also associated with a 10 percent increase in LOS for general when compared to spinal anaesthesia, and a 20 percent increase when compared to general versus local/MAC anaesthesia. Trends toward increased pulmonary complications and LOS were not observed for general versus epidural anaesthesia. No significant association between anaesthesia type and mortality was observed.
“Our study data suggest that increasing the use of less invasive anaesthetic techniques, when appropriate, may limit postoperative complications in EVAR patients,” Professor Matthew Edwards said.
Study finds obese asthmatic children experience more complications with anaesthesia
A study presented at Anesthesiology 2011 found that obese asthmatic children were nearly two times as likely to have at least one respiratory complication during or after surgery compared to their lean peers.
“Respiratory problems are one of the major causes of complications and death during paediatric anaesthesia,” said the study’s lead investigator, Olubukola O. Nafiu, M.D. “Obesity and asthma are commonly cited as risk factors for respiratory problems. This study was designed to examine whether complications were more frequent in obese children with asthma.”
About the Study
The study prospectively examined 1,102 children, 107 (9.7%) obese asthmatics, 118 (10.7%) normal weight asthmatics, 309 (28.0%) obese patients and 568 (51.5%) normal weight non-asthmatics. There was no significant difference in age between or within the groups. Children in the obese-asthmatic and obese groups were more likely to have at least one respiratory complication during or after surgery compared to the other groups. Additionally, obese-asthmatic children were more likely to have a longer post anaesthesia unit stay.
“The association of obesity and asthma with an increase in respiratory complications suggests that obese asthmatic children undergoing anaesthesia should receive additional evaluation and care to prevent the increased potential for complications,” said Dr. Nafiu. “Future investigations into what is directly causing complications in these patients are needed.”
Thousands of lives could be saved if rest of UK adopted average diet in England
Around 4,000 deaths could be prevented every year if the UK population adopted the average diet eaten in England, concludes research published in BMJ Open.
Death rates for cardiovascular disease and cancer are higher in Scotland, Wales, and Northern Ireland than they are in England, and it is well known that these diseases are associated with a poor diet that is high in saturated fats and salt and low in fibre, fruits and vegetables.
The researchers therefore looked at mortality data for coronary heart disease, stroke, and 10 cancers associated with diet, including those of the gullet, bowel, and stomach, in all four UK countries for the years 2007 to 2009 inclusive.
And they estimated average intake of 10 dietary components, including energy intake, in each of the four countries, drawn from national representative data from the Family Food Survey for the same period.
These data showed that people in Scotland and Northern Ireland consistently ate more saturated fat and salt and fewer fruits and vegetables every day than their English cousins, while the differences between Wales and England were less consistent over the three years.
The authors then calculated what differences in death rates could be expected from population changes in average dietary quality, using the DIETRON model - a conceptual mathematical model that calculates the impact of food consumption on health outcomes.
Between 2007 and 2009, just under 22,000 more people died in Wales, Scotland, and Northern Ireland from cardiovascular disease and diet related cancers than would be expected if mortality rates were as low as in England, with most of the difference (mortality gap) accounted for by deaths in Scotland.
The application of the DIETRON model showed that more than 6,000 deaths over the three years could have been prevented or delayed in Scotland - equivalent to 40% of the mortality gap between England and Scotland - if the population had eaten the average diet in England.
The reduction in the mortality gap was even greater for Wales and Northern Ireland, at 81%. This suggests that other non-dietary risk factors contribute to the mortality gap in Scotland.
Deaths from coronary heart disease accounted for the largest proportion of the mortality gap for all three countries.
In all, more than 11,000 deaths could have been prevented or delayed - around half of the excess deaths from cardiovascular disease and diet related cancers - the calculations showed. Differences in total energy intake and fruit and vegetable consumption accounted for most of the variation in death rates.
The authors acknowledge that diet alone cannot close the mortality gap completely, and that the impact of other behavioural risk factors, such as smoking, alcohol, and lack of exercise, also need to be taken into account.
But they conclude: “Diet has a substantial impact on geographical variations in mortality from coronary heart disease, stroke and various cancers within the UK.”
And they suggest that “fat taxes” which have been mooted as a way of nudging people into healthier behaviours, might only work if they are paired with subsidies for fruit and vegetables.
Study finds single dose of erythopoietin reduces transfusion requirements of anaemic cardiac surgical patients, without any side effects
A study presented in the November 2011 issue of Anesthesiology has discovered that administration of a single intravenous dose of erythropoietin, plus iron supplement, one day before surgery, significantly reduced blood transfusion requirements in anemic patients undergoing valvular heart surgery.
The fact that a single intravenous dose of erythropoietin (a glycoprotein hormone that controls red blood cell production) could improve blood conservation is an exciting prospect because blood transfusion during and after surgery is costly and carries some risks.
“Blood transfusion has been associated with adverse outcomes related to kidney injury, neurologic complications, atrial fibrillation, and acute lung injury,” said lead researcher Young-Lan Kwak, M.D., Ph.D. “Thus, the importance of blood conservation strategies to minimise transfusion is being increasingly emphasised, especially since donated blood is such a precious commodity with unpredictable availability.”
Dr. Kwak, a professor in the Severance Biomedical Science Institute, Yonsei University Health System, Seoul, South Korea, said that erythropoietin has been developed to treat anemia caused by reduced red blood cell production resulting from kidney and blood diseases.
However, a conventional regimen of erythropoietin therapy is expensive and requires at least four days of hospitalisation before surgery, and repeated injections are given during the procedure.
Dr. Kwak and his research team wanted to focus on a single-dose therapy that targeted the effects of inflammatory responses caused by anaesthesia and cardiac surgical procedures.
“By targeting the erythropoietin therapy on mitigating the inflammatory response caused by surgical procedures that reduce blood cell production, we hypothesised that a single intravenous administration could reduce transfusion requirements in anemic patients undergoing cardiac surgery,” said Dr. Kwak.
The study involved 74 patients with preoperative anemia who were undergoing valvular heart surgery. One group was given the single dose of erythropoietin with an iron supplement, and the other group was given a placebo of saline solution. Transfusion was required in 86 percent of the saline group, but in only 59 percent of the erythropoietin group.
“Impressively, only a single patient required transfusion after the day of the operation in the erythropoietin group, while several patients were repeatedly transfused during the postoperative period in the saline group,” said Dr. Kwak. “Although further study certainly is required, we observed a significant reduction in transfusion requirements without any side effects. Thus far, our study showed this simple regimen to be safe and effective.”
