What Is Ischemic Preconditioning?

Limb ischemia is a symptom caused by insufficient blood supply to the extremities of the extremities, and is common in patients with diabetes.

Extremity ischemia symptoms

Extremity ischemia

Extremity ischemia overview

Limb ischemia is a symptom caused by insufficient blood supply to the extremities of the extremities, and is common in patients with diabetes.

Extremity ischemia symptoms

Frequent populations are: children, women, pregnant women.

Etiology of acromegaly

Causes of Extremity Ischemic Disease

As a diabetic patient is in a state of hyperglycemia for a long time, the blood viscosity increases. Excessive blood sugar can cause blood vessels to harden, become brittle, thicken, reduce the ability of blood vessels to deform, and insufficient blood supply. On the other hand, blood viscosity increases. It also leads to vascular inflammation, which can lead to thrombosis of blood vessels, resulting in occlusion of blood vessels, leading to severe loss of blood supply, malnutrition of organs, and poor metabolism. If the body tissues and organs are in this state, organ necrosis is easy to cause As the "foot" is farthest from the heart, the blood vessel occlusion is the most serious, which can easily cause edema, blackening, rot, and necrosis, forming foot necrosis. ^[1]

Vascular injury and occlusion can also lead to damage to nerves in damaged tissues, causing autonomic neuropathy of limb blood vessels to weaken blood vessel movement, reduced local tissue resistance, minor trauma can cause infections, and small lesions cannot be timely due to local sensory disturbances. The treatment caused the wound to expand rapidly. At the same time, it is also easy to cause burns due to physical dysfunction. Neuropathy can cause atrophy of the small muscles of the foot. Due to long-term non-adversarial traction, claw-shaped toes (especially the third, fourth, and fifth toes) are formed. This deformity makes the metatarsal head become a support point for plantar load bearing. Due to friction, there is a scab formation, which is extremely prone to infection and penetrating ulcer. Due to the disappearance of deep sensation and impaired joint movement reflex, some patients are overloaded under unconscious conditions, losing the protective effect of repeated repeated trauma, making the joints and articular surfaces very irregular and prone to fractures Dislocations and subluxations of joints, especially metatarsophalangeal joints. ^[2]

Extremity ischemic pathogenesis

The pathology of this disease is mainly atherosclerosis of the arteries and small arteries, microcirculation disorders, which affect the absorption of nutrients and the elimination of metabolites, leading to ischemia, hypoxia, nutritional disorders, and partial loss of vitality. In addition, the resistance to neuropathy declines, pain, temperature disturbance or disappear, so serious injuries, ulcers, gangrene and infection occur, and even amputation is needed. In short, the disease is mainly caused by arterial and microvascular disease caused by ischemia, hypoxia, and tissue inactivation. In addition, the neuropathy is partially unconscious, easily damaged, and complicated by infection.

Arterial vascular occlusion : People with diabetes are prone to atherosclerosis, which causes vascular occlusion of arterial blood vessels, leading to ischemia and hypoxia of extremities, and diabetic gangrene. The reasons are:

Hyperinsulinemia, especially type 2 diabetic obesity, often has a tendency to hyperinsulinemia. Causes fat metabolism disorders, induces and activates fat synthesis enzymes, increases fat synthesis, significantly increases very low density lipoprotein, causes hyperlipoproteinemia, promotes lipid deposition and smooth muscle cell proliferation, and then causes atherosclerosis.
Platelet dysfunction, increased synthesis of txa2, lack of pgl2 synthetase at the intima of arterial lesions, decreased pgl2 synthesis, enhanced platelet aggregation, vascular tendencies to spasm, promoted the occurrence of arterial disease and local vascular obstruction.
Endothelial cells are damaged due to genetic defects and are prone to damage and necrosis. Hyperglycemia causes damage and necrosis. When arterial endothelial cells are damaged, the production and destruction of coagulation factors often lose balance, causing arterial vascular sclerosis and obstruction.

Microvascular basement membrane thickening : Diabetic acne gangrene is closely related to microvascular lesions and capillary basement membrane thickening. Microvascular disease is particularly significant in human body weight-bearing parts. Due to the thickening of the microvascular basement membrane, the exudation of body fluids and proteins causes foot swelling, prevents white blood cells from entering the cells, reduces the anti-infective ability of local tissues, increases white vitality, decreases fibrin activity, and forms microthrombus aggravating ischemia Necrosis, so that festering gangrene, wounds can not heal for a long time.

At the same time as the microvascular basement membrane is thickened, diabetic patients are also accompanied by a change in the chemical structure of the basement membrane thickening, a significant increase in sugar, and a relative reduction in protein and fat. Tissue hypoxia is the direct cause of diabetic microangiopathy. The factors that cause local tissue hypoxia are as follows:

Hemorheological abnormalities, acute stress proglobin, globin, alpha, acid glycoprotein, etc. in plasma increased significantly, promoting the increase of whole blood viscosity and red blood cell aggregation, microvascular perfusion disorders.
The coagulation mechanism is abnormal. The coagulation factors VII and X of fibrinogen and fibrinogen are high in diabetic patients, and the fibrin activity is reduced, which affects local tissue oxygen supply. Platelet agglutination function is enhanced, microcirculation is blocked, and local tissue hypoxia is aggravated.
Glycated hemoglobin increases. Normally, glycated hemoglobin or rapid hemoglobin accounts for 7% of hemoglobin. In diabetes, glycated hemoglobin synthesis increases, about 2-3 times as normal. Difficult to break down, resulting in reduced oxygen separation and tissue hypoxia.
Angiotensin-converting enzyme activity was increased, patients' serum angiotensin-converting enzymes were significantly increased, microangiopathy, and angiotensin-converting enzyme values were higher, suggesting that diabetic patients are in a state of vascular spasm leading to tissue hypoxia.

Diabetic neuropathy : When diabetes is complicated by vascular disease, it is accompanied by peripheral neuropathy and neurophysiological changes. Peripheral nerves cause sensory and motor neurological disorders, muscle atrophy, bone deformation, pain, weakened or disappeared temperature sensation, and trauma or self-injured tissue. Destroy the infection. Autonomic neuropathy results in reduced sweating, dry skin, vasomotor dysfunction, tissue ischemia and brittleness and infection and necrosis. The presence of neuropathy often exposes the body's local tissues to danger. Encountering trauma can lead to extremity gangrene. Diabetic neuropathy interacts with diabetic vascular disease and affects each other to aggravate gangrene infection of local tissues.

Infectious factors : The defense mechanism of uncontrolled diabetic patients is weakened, and the response to invading microorganisms is inhibited at all stages, including neutralizing chemical toxins, bactericidal effects of phagocytic cells of white blood cells, serum ordering factors and cellular immune effects, etc., easily Infection. Once infected, the condition gets worse. Due to neuropathy, extremity sensory disorders and injury infection. Diabetic microangiopathy causes local tissue hypoxia, which is beneficial to the growth of anaerobic bacteria, and changes the oxygen-dependent bactericidal effect of leukocytes. Once infected, platelet adhesion capacity is enhanced, fibrin activity is increased, fibrinolytic activity is reduced, microthrombus is formed and aggravated Ischemic necrosis of local tissue.

Diabetic acne gangrene belongs to the categories of "thirsty disease", "pulse paralysis", and "removal of gangrene" in Chinese medicine. TCM has a long history of treating this disease and has accumulated a lot of valuable experience. TCM believes that the pathogenesis of this disease is mainly thirst, chronic deficiency of qi and yin, stasis of the meridians, impaired blood flow, loss of extremities, and dampness Note: heat poisoning blood stasis, resulting in pulse paralysis and anthrax. Modern elemental medical research has found that there is an abnormal lack of zinc in diabetic human body. After zinc deficiency, the wound healing ability is slow, and it is easy to cause infection and tissue liquefaction, which is the main reason for the ulcer of diabetes. ^[2]

Extremity ischemia diagnosis

A physical examination can diagnose it. ^[3]

Extremity ischemia due to gestational diabetes is suspected. The diagnosis is as follows:

Extremity ischemia examination method

The screening method is to require pregnant women (without fasting) to drink 50gm sugar water, and take a blood test to check the blood glucose value after an hour. If it is greater than 140mg / dL, gestational diabetes is suspected, but the diagnosis cannot be determined. You must further do the so-called "100gm glucose tolerance test", draw blood once on an empty stomach, then drink 100gm sugar water, and then take a blood glucose test after one hour, two hours and three hours Don't start with 100gm for screening diagnosis, because if 50gm blood is drawn once, the possibility can be ruled out, so you don't need to be punctured so many times.

Extremity ischemia diagnostic criteria

Fasting blood glucose: <105mg / dL
1hourafter100gmglucosetaken: <190mg / dL
2hourafter100gmglucosetaken: <165mg / dL
3hourafter100gmglucosetaken: <145mg / dL

If two of the four values are greater than the standard value, the diagnosis of gestational diabetes is determined. Screening for gestational diabetes is recommended between 24 and 28 weeks of pregnancy. Especially for pregnant women who:

Pregnant women who are significantly overweight.
In family history, there is obviously a genetic predisposition to diabetes (many people in the family have diabetes).
Gestational diabetes has preceded pregnancy.
Urine sugar has always been present during the birth check.
Elderly mothers.
Have had a giant baby before (for Taiwanese, a baby weighing more than 4000gm is considered a giant baby); or have been before, at the end of pregnancy, with unexplained death.
The baby is expected to weigh too much (more than two weeks) and / or too much amniotic fluid at the time of delivery.

Differential Acromosis

Gangrene: After tissue necrosis, due to secondary infection of spoilage bacteria and other factors, there are special morphological changes such as black and dark green, called gangrene. Necrotic tissue is decomposed by spoilage bacteria to produce hydrogen sulfide, which combines with iron decomposed from hemoglobin to form iron sulfide, which makes the necrotic tissue black.
Diabetic foot: Diabetic foot refers to the lower limb infection, the formation of ulcers, and / or the destruction of deep tissues caused by diabetic patients with neuropathy and various degrees of peripheral vascular disease.

Extremity ischemia treatment nursing

1. Actively prevent and control infections. Any ulcer and gangrene have potential infection problems, and the infected wounds are not easy to heal. Therefore, the infection must be prevented and controlled first.

(1) Local wound treatment: It is mainly to ensure that the ulcer wound is fully drained and the wound is clean.

(2) Reasonable application of antibiotics: For patients with severe wound infections and poor systemic resistance, broad-spectrum antibiotics can be given in accordance with the doctor's advice to control the infection.

(3) Pay attention to the external environment: to ensure the cleanliness of the ward environment, bed sheets and patient skin. The skin around the ulcer wound can be gently washed with warm water and neutral soap, and then wiped dry with a cotton ball. Avoid squeezing wounds and damaging surrounding skin.

2. Promote the growth of granulation tissue and accelerate wound healing. As long as the ulcer wound has sufficient blood supply, no infection and necrosis, and the dressing is non-irritating and moist and breathable, the granulation tissue will grow rapidly and accelerate the healing of the wound.

(1) Pay attention to local treatment and care:

Thromboembolic vasculitis, occlusive arteriosclerosis and other chronic limb arterial occlusive diseases, local treatment of necrotic wounds is very important, which is important for improving the efficacy, shortening the course of treatment and preserving the limbs, so the nursing staff should assist the doctor Remove necrotic tissue from ulcer wounds in time. We often use the "cannibalization method": necrotic tissue is removed in stages and batches when changing dressings. The specific methods are: distal necrotic tissue is removed first, and proximal necrosis is removed first; loose necrotic tissue is removed first, followed by firm removal; soft tissue is removed first, and dead bone is removed; inflammation completely subsides or is controlled, and necrotic tissue is separated from healthy tissue. Completely remove it after obvious formation, but pay attention to local blood supply.

(2) Improve local blood circulation:

Prevent the affected part from being compressed. Pay attention to turning over when lying down to reduce the local compression time. If necessary, use a quilt. Ulcers caused by insufficient arterial blood supply, guiding patients to exercise exercises on the affected limb is an effective method to promote blood circulation in the affected limb. The practice is: the patient lies on his back, first raise the affected limb to 45 °, maintain it for 1 to 2 minutes, then sit up and lie on the bedside for 2 to 5 minutes, and do ankle and foot rotation and extension and flexion activities more than 10 times, and then lie on the bed Rest for 2 minutes. Ulcers caused by venous reflux disorders. Raise the affected limb when bedridden, and perform ankle dorsiflexion, rotation, and calf flexion and extension exercises on the bed to play the role of muscle pump of the lower limbs to promote venous return. If necessary, elastic bandages or elastic force Socks help promote venous return.

(3) Reasonable diet to improve the nutritional status of the whole body:

Adjust the diet structure according to the illness and the patient's eating habits, and encourage patients to eat a high-protein, high-vitamin diet. Anemia, mild food can eat high iron content, severe, should be intermittent blood transfusion, oral zinc sulfate, can provide the trace element zinc required for wounds. Research data confirms that patients with peripheral vascular disease often have high-coagulation and high-viscosity blood. Therefore, high-fat diets should be restricted, and a reasonable diet and vegetarian diet should be promoted. They should eat less spicy foods and thicker flavors, and adhere to the principle of light diet.

3. Active treatment of primary disease is the key to prevent recurrence of ulcer. Peripheral vascular disease of foot ulcers and gangrene is a chronic process clinically, which is difficult to heal and recurs. The primary disease is based on foot ulcers and gangrene. The primary pathogenesis of ulcers and gangrene has also improved, but healing of ulcers and gangrene does not mean that the primary pathology is cured. Therefore, according to the principle of treating both the original and the specimen in the treatment of the disease, actively treating the primary disease is the key to preventing the recurrence of ulcers and gangrene. The author has realized in practice that the combination of traditional Chinese and western medicine for the treatment of diseases and syndromes, and overall comprehensive treatment and nursing care are effective measures to treat such diseases. ^[4]

Extremity ischemia preventive care

When the nail has red or black spots, we can massage the wells on the fingers to prevent it.

Extremity ischemia caused by diabetes should actively control blood sugar. The common prevention methods are as follows:

Do not overeating, have a regular life, eat slowly, eat more vegetables, and try not to eat foods containing glucose and sucrose in a short period of time. This can prevent blood sugar from rising rapidly in a short period of time and protect the pancreas. Function is helpful, especially for friends with family history of diabetes must remember!
Have a regular sex life to prevent infectious diseases; do not eat excessive antibiotics. Some viral infections and excessive antibiotics can trigger diabetes.
Friends with abnormal glucose tolerance or family history of diabetes can prevent the occurrence of diabetes to the greatest extent: eat nicotinamide, Vb1, Vb6, methyl Vb12 (Micopro) for three months each year to enhance pancreatic function; during seasonal changes Eating Vc and Ve for half a month, the dosage should be large, which can improve self immunity and eliminate free radicals.
Exercise more and stay up late.
Intake of sugar This is a relative term. Inability to eat sugar means that people cannot eat sucrose and glucose directly in their daily diet. Fructose can be eaten. The decomposition of fructose does not require insulin. However, the main components of honey are fructose and glucose. Patients are advised to eat honey with caution. ^[5]