Surgical Site Infections

Overview

Definition

Surgical site infection Surgical site infection Infection occurring at the site of a surgical incision. Surgical Complications (SSI) is an infection that occurs at or near a surgical incision or deep to it within 30 days of the procedure or within 90 days if prosthetic material is implanted.

Classification of surgical site infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease

• Superficial: involves skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions and subcutaneous tissue Subcutaneous tissue Loose connective tissue lying under the dermis, which binds skin loosely to subjacent tissues. It may contain a pad of adipocytes, which vary in number according to the area of the body and vary in size according to the nutritional state. Soft Tissue Abscess
• Deep: involves fascial and/or muscle layers
• Organ/space: involves organs or spaces deep to the incision (e.g., intraabdominal abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease)

Classification of surgical wounds

Surgical wounds are classified from clean to dirty on the basis of the increasing risk of infection.

Pathophysiology

Contamination of surgical wounds occurs to some degree in all surgical procedures. However, in most cases, the infecting agents do not overcome host defenses. For SSI to occur, the bacterial colonization Colonization Bacteriology must trigger Trigger The type of signal that initiates the inspiratory phase by the ventilator Invasive Mechanical Ventilation an immune response.

Risk factors

Procedural factors:

• Violations of sterile Sterile Basic Procedures technique (i.e., poor skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions preparation, contamination of instruments, inadequate handwashing/scrubbing)
• Inadequate or ill-timed antibiotic prophylaxis Prophylaxis Cephalosporins
• Prolonged procedure time
• Local tissue necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
• Hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception formation
• Use of foreign material in wounds (e.g., drains, mesh)
• Preoperative shaving
• Prolonged preoperative hospital stay (↑ nosocomial infection Nosocomial infection Nosocomial infections include intravascular catheter-related infections, catheter-associated urinary tract infections (CAUTIs), hospital-acquired pneumonia (HAP), ventilator-associated pneumonia (VAP), Clostridioides difficile infections (CDIs), and surgical site infections. Multidrug-resistant Organisms and Nosocomial Infections)
• Contamination with bowel contents

Patient factors:

• Advanced age (> 65 years)
• Prior surgical infection Surgical infection An infection is the proliferation of microorganisms within tissues, body cavities, or spaces, which induces an immune response and overwhelms the body’s natural defenses. In surgical patients, these infections are frequently caused by the translocation of commensal organisms into deeper tissues, combined with the impairment of host defenses due to surgical injury or stress. Surgical Infections
• Malnutrition Malnutrition Malnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema). Malnutrition in children in resource-limited countries
• Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
• Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus
• Hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
• Hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome
• Hyperglycemia Hyperglycemia Abnormally high blood glucose level. Diabetes Mellitus
• Immunosuppression
• Therapy with corticosteroids Corticosteroids Chorioretinitis
• Chronic inflammation Chronic Inflammation Inflammation
• Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
• Renal failure Renal failure Conditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate. Crush Syndrome
• Peripheral vascular disease (PVD)
• Anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types
• Previous radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma of surgical site
• Chronic skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions disease
• Carrier Carrier Vaccination state (e.g., chronic Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus carriage)

Pathogenesis

When the virulence factors Virulence factors Those components of an organism that determine its capacity to cause disease but are not required for its viability per se. Two classes have been characterized: toxins, biological and surface adhesion molecules that affect the ability of the microorganism to invade and colonize a host. Haemophilus of a microorganism are sufficient to overcome the innate and adaptive immune responses, a clinically important infection occurs in the following manner:

1. Once microbes enter, host defenses (i.e., tissue barriers, iron-sequestering lactoferrin and transferrin Transferrin An iron-binding beta1-globulin that is synthesized in the liver and secreted into the blood. It plays a central role in the transport of iron throughout the circulation. Heme Metabolism, and fibrinogen Fibrinogen Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides a and b, the proteolytic action of other enzymes yields different fibrinogen degradation products. Hemostasis) act to limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation and/or eliminate all pathogens.
2. Resident macrophages Macrophages The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood monocytes. Main types are peritoneal macrophages; alveolar macrophages; histiocytes; kupffer cells of the liver; and osteoclasts. They may further differentiate within chronic inflammatory lesions to epithelioid cells or may fuse to form foreign body giant cells or langhans giant cells. Innate Immunity: Phagocytes and Antigen Presentation secrete cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response ( tumor Tumor Inflammation necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage factor α (TNF-α); IL-1β, 6, and 8; and interferon (IFN-γ)) within the tissue milieu and the systemic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment.
3. Microbial opsonization, phagocytosis Phagocytosis The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (phagocytes). Innate Immunity: Phagocytes and Antigen Presentation, and extracellular and intracellular microbial destruction occur via cellular ingestion.
4. At the same time, the classical and alternative complement pathways are activated and vascular permeability increases.
5. Inflammatory fluid and neutrophils Neutrophils Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes. Innate Immunity: Phagocytes and Antigen Presentation flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure into the area of infection.
6. Possible outcomes:
   • The microorganism is eradicated.
   • Containment in the parenchyma (i.e., abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease)
   • Localized infection, displaying local symptoms (i.e., cellulitis Cellulitis Cellulitis is a common infection caused by bacteria that affects the dermis and subcutaneous tissue of the skin. It is frequently caused by Staphylococcus aureus and Streptococcus pyogenes. The skin infection presents as an erythematous and edematous area with warmth and tenderness. Cellulitis)
   • Systemic infection ( bacteremia Bacteremia The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion. Glycopeptides or fungemia Fungemia The presence of fungi circulating in the blood. Opportunistic fungal sepsis is seen most often in immunosuppressed patients with severe neutropenia or in postoperative patients with intravenous catheters and usually follows prolonged antibiotic therapy. Chronic Granulomatous Disease) with its accompanying presentation (i.e., fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children)

Clinical Presentation

Systemic inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation:

• Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
• Tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children
• Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination

Local inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation:

• Local erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion
• Tenderness
• Purulent discharge Purulent Discharge Dacryocystitis
• Peritoneal signs in organ/space abdominal infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
• Abscesses close to the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions are painful, and the overlying skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions is swollen, erythematous, and warm.

Septic shock Septic shock Sepsis associated with hypotension or hypoperfusion despite adequate fluid resuscitation. Perfusion abnormalities may include, but are not limited to lactic acidosis; oliguria; or acute alteration in mental status. Sepsis and Septic Shock:

• Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
• Pallor
• Sweating
• Rigors Rigors Fever
• Confusion ( altered mental status Altered Mental Status Sepsis in Children) 

Diagnosis

The diagnosis of SSI relies primarily on clinical findings. Diagnostic imaging and laboratory studies are helpful for identifying deep tissue and organ/space infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease.

Physical exam

Clinical findings (local):

• Purulent exudate Exudate Exudates are fluids, cells, or other cellular substances that are slowly discharged from blood vessels usually from inflamed tissues. Pleural Effusion draining from the surgical site
• A surgical site that has reopened in the setting of ≥ 1 clinical sign of infection ( pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, swelling Swelling Inflammation, erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion, warmth) 
• Erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion, swelling Swelling Inflammation, fluctuance Fluctuance Examination of the Breast, and/or induration Induration Dermatologic Examination around the incision
• Organ/space infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease:
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever/ chills Chills The sudden sensation of being cold. It may be accompanied by shivering. Fever/signs of sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock
  • Localized abdominal tenderness with peritoneal signs

Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock findings (systemic):

• Criteria for systemic inflammatory response syndrome Systemic Inflammatory Response Syndrome Sepsis in Children (SIRS):
  • Temperature > 38°C (100.4°F) or < 35°C (95°F)
  • HR > 90/minute
  • RR RR Relative risk (RR) is the risk of a disease or condition occurring in a group or population with a particular exposure relative to a control (unexposed) group. Measures of Risk > 20 or partial pressure Partial pressure The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. Gas Exchange of carbon dioxide (PaCO₂) < 35 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma Hg
  • WBC > 12,000 ( leukocytosis Leukocytosis A transient increase in the number of leukocytes in a body fluid. West Nile Virus) or < 4000 (leukopenia)
• Sequential Organ Failure Assessment Sequential Organ Failure Assessment Sepsis in Children ( SOFA SOFA Sepsis and Septic Shock):
  • Mortality Mortality All deaths reported in a given population. Measures of Health Status prediction score 
  • Used to track a person’s status during the stay in an ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus
  • Based on an assessment of the degree of dysfunction of 6 organ systems. 
  • The score is calculated at admission and every 24 hours until discharge.
  • Quick SOFA SOFA Sepsis and Septic Shock ( qSOFA qSOFA Presence of 2 of the following 3 criteria indicates a worse outcome in a patient suspected of having sepsis and triggers an immediate diagnostic workup and treatment as appropriate. Sbp < 100 mm hg, respiratory rate > 22/min, altered mental status. Types of Shock) is an abbreviated assessment tool (poorly sensitive, but decently specific for the risk of death):
    • RR RR Relative risk (RR) is the risk of a disease or condition occurring in a group or population with a particular exposure relative to a control (unexposed) group. Measures of Risk ≥ 22/minute
    • Altered mentation
    • Systolic BP ≤ 100 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma Hg

Laboratory

• CBC: WBC > 10,000 ( leukocytosis Leukocytosis A transient increase in the number of leukocytes in a body fluid. West Nile Virus)
• Serum creatinine
• BUN
• CRP
• Microbiology:
  • Gram staining Gram staining Bacteriology and culture of a wound or aspiration
  • Blood cultures in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who are febrile or have suspected sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock

Diagnostic imaging

• Deep tissue or organ/space SSIs may require radiologic imaging for definitive diagnosis.
• Prosthetic infection (e.g., hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias mesh) may also require imaging to support the diagnosis.
• CT, MRI, or ultrasonography can identify abdominal, pelvic, and soft tissue Soft Tissue Soft Tissue Abscess abscesses.
• Imaging is needed for percutaneous or surgical drainage planning.

Management

The management of SSIs may include antibiotics, abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease drainage (open or percutaneous), and removal of infected prosthetic material.

Antibiotic therapy

• Reserved for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with significant cellulitis Cellulitis Cellulitis is a common infection caused by bacteria that affects the dermis and subcutaneous tissue of the skin. It is frequently caused by Staphylococcus aureus and Streptococcus pyogenes. The skin infection presents as an erythematous and edematous area with warmth and tenderness. Cellulitis, SIRS, or organ/space or prosthetic infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
• Antibiotic choice depends on the procedure performed/type of wound:
  • Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease associated with skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions flora mostly require gram-positive Gram-Positive Penicillins coverage as well consideration for possible methicillin Methicillin One of the penicillins which is resistant to penicillinase but susceptible to a penicillin-binding protein. It is inactivated by gastric acid so administered by injection. Penicillins resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing.
  • Contamination with intestinal flora requires gram-negative and anaerobic coverage.

Surgical therapy

• Superficial wound infection/ abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease:
  • Opening the wound 
  • Allowing the wound to heal by secondary intention Secondary intention When there are significant tissue losses and the wound surface cannot be brought together (e.g., lacerations, burns, and ulcers) Wound Healing with daily packing/dressing changes 
• Deep wound infection with fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis/muscle involvement:
  • Opening the wound
  • Debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome of infected/ devitalized tissue may be needed.
  • Daily packing/dressing changes for the wound; may benefit from vacuum wound therapy
• Organ/space infection:
  • Very small abscesses (< 3 cm) may resolve with antibiotic therapy alone.
  • Larger abscesses usually require either percutaneous or operative drainage.
• Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease involving prosthetic materials:
  • Initial therapy is antibiotics with drainage of all associated abscesses.
  • Salvage may be attempted if there is good clinical response to antibiotics and drainage, but most of the time, removal of the prosthetic material is required.

Prevention

• Adherence to sterile Sterile Basic Procedures technique
• Appropriate antibiotic prophylaxis Prophylaxis Cephalosporins
• Bowel preparation (cleansing) when feasible in cases involving bowel resection/anastomosis
• Optimizing patient’s condition ( smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation, adequate nutrition, blood glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance control, avoiding hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia in the OR)