Chronic critical illness

Last updated
A respiratory therapist examining a mechanically ventilated patient on an Intensive Care Unit; protracted mechanical ventilation is a hallmark of chronic critical illness Respiratory therapist.jpg
A respiratory therapist examining a mechanically ventilated patient on an Intensive Care Unit; protracted mechanical ventilation is a hallmark of chronic critical illness

Chronic critical illness is a disease state which affects intensive care patients who have survived an initial insult but remain dependent on intensive care for a protracted period, neither dying nor recovering. [1] The most characteristic clinical feature is a prolonged requirement for mechanical ventilation. [2] Other features include profound weakness associated with critical illness polyneuropathy and myopathy, increased susceptibility to infection, metabolic changes and hormonal changes. There may be protracted or permanent delirium, or other marked cognitive impairment. The physical and psychological symptoms of the disease are very severe, including a propensity to develop post traumatic stress syndrome. [3]

Mechanical ventilation, or assisted ventilation, is the medical term for artificial ventilation where mechanical means are used to assist or replace spontaneous breathing. This may involve a machine called a ventilator, or the breathing may be assisted manually by a suitably qualified professional, such as an anesthesiologist, respiratory therapist, or paramedic, by compressing a bag valve mask device.

Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) are overlapping syndromes of diffuse, symmetric, flaccid muscle weakness occurring in critically ill patients and involving all extremities and the diaphragm with relative sparing of the cranial nerves. CIP and CIM have similar symptoms and presentations and are often distinguished largely on the basis of specialized electrophysiologic testing or muscle and nerve biopsy. The causes of CIP and CIM are unknown, though they are thought to be a possible neurological manifestation of systemic inflammatory response syndrome. Corticosteroids and neuromuscular blocking agents, which are widely used in intensive care, may contribute to the development of CIP and CIM, as may elevations in blood sugar, which frequently occur in critically ill patients.

Myopathy is a disease of the muscle in which the muscle fibers do not function properly. This results in muscular weakness. Myopathy means muscle disease. This meaning implies that the primary defect is within the muscle, as opposed to the nerves or elsewhere. Muscle cramps, stiffness, and spasm can also be associated with myopathy.

Strict definitions of chronic critical illness vary. One definition is the requirement for mechanical ventilation for 21 days or more. It is estimated that 5-10% of patients who require mechanical ventilation as part of their initial illness will go on to develop chronic critical illness. [2] Overall prevalence has been estimated at 34.4 per 100 000 of the population. [4] Most adult patients do not survive chronic critical illness, and furthermore even those who are discharged from hospital frequently die soon after discharge. [3] One-year mortality in adults is 48-68%. [2] However, children fare better with two-thirds surviving to 5 years or beyond. [5]

See also

Related Research Articles

Acute respiratory distress syndrome Human disease

Acute respiratory distress syndrome (ARDS) is a type of respiratory failure characterized by rapid onset of widespread inflammation in the lungs. Symptoms include shortness of breath, rapid breathing, and bluish skin coloration. Among those who survive, a decreased quality of life is relatively common.

Bronchopulmonary dysplasia Human disease

Bronchopulmonary dysplasia is a chronic lung disease in which premature infants, usually those who were treated with supplemental oxygen, require long-term oxygen. It is more common in infants with low birth weight (LBW) and those who receive prolonged mechanical ventilation to treat respiratory distress syndrome (RDS). It results in significant morbidity and mortality. The definition of BPD has continued to evolve since then primarily due to changes in the population, such as more survivors at earlier gestational ages, and improved neonatal management including surfactant, antenatal glucocorticoid therapy, and less aggressive mechanical ventilation.

Positive end-expiratory pressure (PEEP) is the pressure in the lungs above atmospheric pressure that exists at the end of expiration. The two types of PEEP are extrinsic PEEP and intrinsic PEEP. Pressure that is applied or increased during an inspiration is termed pressure support.

Löfgren syndrome

Löfgren syndrome is a type of acute sarcoidosis that is frequent in Scandinavian, Irish, African and Puerto Rican women. It was described in 1953 by Sven Halvar Löfgren, a Swedish clinician. Some have considered the condition to be imprecisely defined.

Restrictive lung diseases are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.

Ventilator-associated lung injury (VALI) is an acute lung injury that develops during mechanical ventilation and is termed ventilator-induced lung injury (VILI) if it can be proven that the mechanical ventilation caused the acute lung injury. In contrast, ventilator-associated lung injury (VALI) exists if the cause cannot be proven. VALI is the appropriate term in most situations because it is virtually impossible to prove what actually caused the lung injury in the hospital.

Pulmonary hygiene, is a set of methods used to clear mucus and secretions from the airways. The word pulmonary refers to the lungs. The word toilet, related to the French toilette, refers to body care and hygiene; this root is used in words such as toiletry that also relate to cleansing.

Critical illness-related corticosteroid insufficiency is a form of adrenal insufficiency in critically ill patients who have blood corticosteroid levels which are inadequate for the severe stress response they experience. Combined with decreased glucocorticoid receptor sensitivity and tissue response to corticosteroids, this adrenal insufficiency constitutes a negative prognostic factor for intensive care patients.

Acute exacerbation of chronic obstructive pulmonary disease

Acute exacerbation of COPD is a sudden worsening of COPD symptoms that typically lasts for several days. It may be triggered by an infection with bacteria or viruses or by environmental pollutants. Typically, infections cause 75% or more of the exacerbations; bacteria can roughly be found in 25% of cases, viruses in another 25%, and both viruses and bacteria in another 25%. Airway inflammation is increased during the exacerbation resulting in increased hyperinflation, reduced expiratory air flow and decreased gas exchange.

Airway pressure release ventilation pressure control mode of mechanical ventilation

Airway pressure release ventilation (APRV) is a pressure control mode of mechanical ventilation that utilizes an inverse ratio ventilation strategy. APRV is an applied continuous positive airway pressure (CPAP) that at a set timed interval releases the applied pressure. Depending on the ventilator manufacturer, it may be referred to as BiVent. This is just as appropriate to use, since the only difference is that the term APRV is copyrighted.

Modes of mechanical ventilation are one of the most important aspects of the usage of mechanical ventilation. The mode refers to the method of inspiratory support. In general, mode selection is based on clinician familiarity and institutional preferences, since there is a paucity of evidence indicating that the mode affects clinical outcome. The most frequently used forms of volume-limited mechanical ventilation are intermittent mandatory ventilation (IMV) and continuous mandatory ventilation (CMV). There have been substantial changes in the nomenclature of mechanical ventilation over the years, but more recently it has become standardized by many respirology and pulmonology groups. Writing a mode is most proper in all capital letters with a dash between the control variable and the strategy

Hyperinflation therapy (HIT) is a very common therapy performed on patients who are suffering from some sort of respiratory distress. The therapy involves applying volumes greater than normal to reinflate the collapsed alveoli in the lungs. There are many different techniques used to administer hyperinflation therapy. The respiratory therapist typically decides which method is best for each patient.

Intermittent Mandatory Ventilation (IMV) refers to any mode of mechanical ventilation where a regular series of breaths are scheduled but the ventilator senses patient effort and reschedules mandatory breaths based on the calculated need of the patient. Similar to continuous mandatory ventilation in parameters set for the patients pressures and volumes but distinct in its ability to support a patient by either supporting their own effort or providing support when patient effort is not sensed. IMV is frequently paired with additional strategies to improve weaning from ventilator support or to improve cardiovascular stability in patients who may need full life support.

Inverse ratio ventilation (IRV) is not necessarily a mode of mechanical ventilation though it may be referred to as such. IRV is a strategy of ventilating the lungs in such a way that the amount of time the lungs are in inhalation is greater than the amount of time they are in exhalation, allowing for a constant inflation of the lungs, ensuring they remain "recruited". The primary goal for IRV is improved oxygenation by forcing inspiratory time to be greater than expiratory time increasing the mean airway pressure and potentially improving oxygenation. Normal I:E ratio is 1:2, 1:3, 1:4, so forcing the I:E to be 2:1, 3:1, 4:1, is the source of the term for the strategy.

Blood gas tension refers to the partial pressure of gases in blood. There are several significant purposes for measuring gas tension; the most common gas tensions measured are oxygen tension (PxO2), the carbon dioxide tension (PxCO2) and carbon monoxide tension (PxCO). The subscript x in each symbol represents the source of the gas being measured; "a" meaning arterial, "A" being alveolar, "v" being venous, "c" being capillary. Blood gas tests (such as arterial blood gas tests) measure these partial pressures.

A respiratory driven protocol is an algorithmic medical process applied by respiratory practitioners as an extension of the physician. Respiratory-driven protocols are implemented in hospitals for treatment of people suffering from asthma, bronchiolitis, and other respiratory illness. Respiratory-driven protocols are most widely applied in intensive-care units. Respiratory practitioners are not utilized globally, so most application of respiratory practitioners as physician-extenders in this fashion is in the United States.

Prone ventilation refers to mechanical ventilation with the patient lying face-down (prone). It improves oxygenation in most patients with acute respiratory distress syndrome (ARDS) and improves mortality. The mechanism behind this effect is uncertain.

Post-intensive care syndrome (PICS) describes a collection of health disorders that are common among patients who survive critical illness and intensive care. Generally, PICS is considered distinct from the impairments experienced by those who survive critical illness and intensive care following traumatic brain injury and stroke. The range of symptoms that PICS describes falls under three broad categories: physical impairment, cognitive impairment, and psychiatric impairment. A person with PICS may have symptoms from all three categories or just one. A video overview is available.

References

  1. ↑ Girard K, Raffin TA. The chronically critically ill: to save or let die? Respir Care. 1985; 30: 339-47. PMID   10315661
  2. 1 2 3 Nelson JE, Cox CE, Hope AA, Carson SS. Chronic critical illness. Am J Respir Crit Care Med. 2010; 182(4): 446-54. PMID   20448093
  3. 1 2 Nelson JE, Meier DE, Litke A, Natale DA, Siegel RE, Morrison RS. The symptom burden of chronic critical illness. Crit Care Med. 2004; 32(7): 1527-34. PMID   15241097
  4. ↑ Kahn JM, Le T, Angus DC, Cox CE, Hough CL, White DB et al. The epidemiology of chronic critical illness in the United States. Crit Care Med. 2005; 43(2): 282-7. PMID   25377018
  5. ↑ Namachivayam SP, Alexander J, Slater A, Millar J, Erickson S, Tibballs J et al. Five-Year Survival of Children With Chronic Critical Illness in Australia and New Zealand Crit Care Med. 2015; 43(9): 1978-85. PMID   25962079
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.