Perioperative mortality
Encyclopedia
Perioperative mortality is mortality
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....

 in relation to surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

, often defined as death within two weeks of a surgical procedure. An important consideration in the decision to perform any surgical procedure is to weigh the benefits against the risks. Anesthesiologist
Anesthesiologist
An anesthesiologist or anaesthetist is a physician trained in anesthesia and peri-operative medicine....

s and surgeon
Surgeon
In medicine, a surgeon is a specialist in surgery. Surgery is a broad category of invasive medical treatment that involves the cutting of a body, whether human or animal, for a specific reason such as the removal of diseased tissue or to repair a tear or breakage...

s employ various methods in assessing whether a patient is in optimal condition from a medical standpoint prior to undertaking surgery, and various statistical tools are available.

Intraoperative causes

Complications during surgery, e.g. bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...

 or perforation of organs may have lethal sequelae.

Infectious complications

Local infection of the operative field is prevented by using sterile technique
Asepsis
Asepsis is the state of being free from disease-causing contaminants or, preventing contact with microorganisms. The term asepsis often refers to those practices used to promote or induce asepsis in an operative field in surgery or medicine to prevent infection...

, and prophylactic antibiotics
Chemoprophylaxis
Chemoprophylaxis refers to the administration of a medication for the purpose of preventing disease or infection. Antibiotics, for example, may be administered to patients with disorders of immune system function to prevent bacterial infections...

 are often given in abdominal surgery or patients known to have a heart defect or mechanical heart valves
Artificial heart valve
An artificial heart valve is a device implanted in the heart of a patient with heart valvular disease. When one of the four heart valves malfunctions, the medical choice may be to replace the natural valve with an artificial valve. This requires open-heart surgery.Valves are integral to the normal...

 that are at risk of developing endocarditis
Endocarditis
Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...

.

Thromboembolic complications

Examples are deep vein thrombosis
Deep vein thrombosis
Deep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...

 and pulmonary embolism
Pulmonary embolism
Pulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...

, the risk of which can be mitigated by certain interventions, such as the administration of anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

s (e.g., warfarin
Warfarin
Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...

 or low molecular weight heparin
Low molecular weight heparin
In medicine, low-molecular-weight heparin is a class of medication used as an anticoagulant in diseases that feature thrombosis, as well as for prophylaxis in situations that lead to a high risk of thrombosis....

s), antiplatelet drug
Antiplatelet drug
An antiplatelet drug is a member of a class of pharmaceuticals that decrease platelet aggregation and inhibit thrombus formation...

s (e.g., aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...

), compression stockings
Compression stockings
Compression stockings and socks are specialised hosiery items designed to increase blood circulation. Their main theraputic purpose is to provide graduated pressure on the lower leg and foot and, in some cases, the thigh, to alleviate circulatory problems such as edema, phlebitis and...

, and cyclical pneumatic calf compression
Sequential compression device
Sequential compression device, abbreviated SCD, is an improved type of intermittent pneumatic compression system that includes inflatable compression sleeves and a characteristic pressure modulation in order to reduce risk of clot formation, such as deep vein thrombosis, in the legs of hospitalized...

 in high risk patients.

Pulmonary complications

Respiratory therapy
Respiratory therapy
Respiratory therapy is a healthcare profession in which specialists work with patients suffering from either acute or chronic respiratory problems. These specialists are termed Respiratory Therapists in most places internationally but may also be referred to as Respiratory Scientists or...

 has a place in preventing pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...

 related to atelectasis
Atelectasis
Atelectasis is defined as the collapse or closure of alveoli resulting in reduced or absent gas exchange. It may affect part or all of one lung. It is a condition where the alveoli are deflated, as distinct from pulmonary consolidation.It is a very common finding in chest x-rays and other...

, which occurs especially in patients recovering from thoracic and abdominal surgery.

Neurologic complications

Stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

 occurs at a higher rate during the postoperative period.

Hepatorenal complications

In patients with cirrhosis
Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...

, the perioperative mortality is predicted by the Child-Pugh score
Child-Pugh score
In medicine , the Child-Pugh score is used to assess the prognosis of chronic liver disease, mainly cirrhosis...

.

Epidemiology

In many countries, statistics are kept by mandatory reporting of perioperative mortality. These may then be used in league table
League table
A league table, standings, ranking chart, or ladder is a chart or list which compares sports teams, institutions, nations or companies by ranking them in order of ability or achievement. A league table may list several related statistics, but they are generally sorted by the primary one that...

s that compare the quality of hospitals. Critics of this system point out that perioperative mortality may not reflect poor performance but could be caused by other factors, e.g. a high proportion of acute/unplanned surgery. Most hospitals have regular meetings to discuss surgical complications and perioperative mortality. Specific cases may be investigated more closely if a preventable cause has been identified.

Most perioperative mortality is attributable to complications
Complication (medicine)
Complication, in medicine, is an unfavorable evolution of a disease, a health condition or a medical treatment. The disease can become worse in its severity or show a higher number of signs, symptoms or new pathological changes, become widespread throughout the body or affect other organ systems. A...

 from the operation (such as bleeding, sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

, and failure of vital organs) or pre-existing medical conditions
Comorbidity
In medicine, comorbidity is either the presence of one or more disorders in addition to a primary disease or disorder, or the effect of such additional disorders or diseases.- In medicine :...

. Mortality directly related to anesthetic management is less common, and may include such causes as pulmonary aspiration
Pulmonary aspiration
Pulmonary aspiration is the entry of material from the oropharynx or gastrointestinal tract into the larynx and lower respiratory tract...

 of gastric contents, asphyxia
Asphyxia
Asphyxia or asphyxiation is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs...

tion and anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...

. These in turn may result from malfunction of anesthesia-related equipment
Instruments used in anesthesiology
Following is a list of instruments used in the practice of anesthesia:-Instrument list:- Anesthetic machine :General anesthesia does not require the anesthetic machine, tested daily, as basic equipment...

 or more commonly, human error
Human reliability
Human reliability is related to the field of human factors engineering and ergonomics, and refers to the reliability of humans in fields such as manufacturing, transportation, the military, or medicine...

. A 1978 study found that 82% of preventable anesthesia mishaps were the result of human error.

In a 1954 review of 599,548 surgical procedures at 10 hospitals in the United States between 19481952, 384 deaths were attributed to anesthesia, for an overall mortality rate
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 of 0.64%. In 1984, after a television program highlighting anesthesia mishaps aired in the United States, American anesthesiologist Ellison C. Pierce appointed a committee called the Anesthesia Patient Safety and Risk Management Committee of the American Society of Anesthesiologists
American Society of Anesthesiologists
The American Society of Anesthesiologists is an association of physicians, primarily anesthesiologists, that share a common goal of raising the standard of the medical specialty of anesthesiology and the improvement of patient care by fostering and encouraging education through research and...

. This committee was tasked with determining and reducing the causes of peri-anesthetic morbidity and mortality. An outgrowth of this committee, the Anesthesia Patient Safety Foundation was created in 1985 as an independent, nonprofit corporation with the vision that "that no patient shall be harmed by anesthesia".

The current mortality attributable to the management of general anesthesia is controversial. Most current estimates of perioperative mortality range from 1 death in 53 anesthetics to 1 in 5,417 anesthetics. The incidence of perioperative mortality that is directly attributable to anesthesia ranges from 1 in 6,795 to 1 in 200,200 anesthetics. There are some studies however that report a much lower mortality rate. For example, a 1997 Canadian retrospective review
Retrospective cohort study
A retrospective cohort study, also called a historic cohort study, generally means to take a look back at events that already have taken place...

 of 2,830,000 oral surgical
Oral Surgery
Oral Surgery is a recognized international specialty in dentistry. It includes the diagnosis, surgical and related treatment of diseases, injuries and defects involving both the functional and esthetic aspects of the hard and soft tissues of the head, mouth, teeth, gums, jaws and neck.It involves,...

 procedures in Ontario between 19731995 reported only four deaths in cases in which either an oral and maxillofacial surgeon
Oral and maxillofacial surgery
Oral and maxillofacial surgery is surgery to correct a wide spectrum of diseases, injuries and defects in the head, neck, face, jaws and the hard and soft tissues of the oral and maxillofacial region. It is an internationally recognized surgical specialty...

 or a dentist
Dentistry
Dentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...

 with specialized training in anesthesia administered the general anesthetic or deep sedation. The authors calculated an overall mortality rate of 1.4 per 1,000,000. It is suggested that these wide ranges may be caused by differences in operational definitions and reporting sources.

The largest and most recent study of postoperative mortality was published in 2010. In this review of 3.7 million surgical procedures at 102 hospitals in the Netherlands during 19912005, postoperative mortality from all causes was observed in 67,879 patients, for an overall rate of 1.85%.

Anaesthesiologists are committed to continuously reducing perioperative mortality and morbidity. In 2010, the principal European anaesthesiology organisations launched The Helsinki Declaration for Patient Safety in Anaesthesiology
The Helsinki Declaration for Patient Safety in Anaesthesiology
The Helsinki Declaration for Patient Safety in Anaesthesiology is a document prepared jointly by the two principal anaesthesiology organizations in Europe, The European Board of Anaesthesiology and the European Society of Anaesthesiology . It was launched in June 2010 at the Euroanaesthesia...

, a practically-based manifesto for improving anaesthesia care in Europe.
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