Respiratory unit

The size of the fibrous particles that appear to induce disease in the animal models is compatible with the measured respiratory range in humans (Lipp-man, 1977). Most particulate deposition takes place not in the upper or conducting portion of the airways but in the alveolar region of the pulmonary tree (the respiratory unit). Some surface deposition may occur at bifurcations in the bronchial tree, but the actual amount at each location is influenced by anatomy, specific to the species—probably to an individual—as well as the variety of fiber. A large proportion of airborne particulates are rejected as part of the normal clearance mechanisms in animals, but in humans clearance mechanisms may be compromised by smoking, for example. We are unaware of any experiments on fiber toxicity using smoking rats ... 

Figure 6.8 Schematic representation of the respiratory unit of the lung. (From Bloom and Fawcett, in A Textbook of Histology, Philadelphia Saunders, 1975.)...

Emery JL Mithal A (1960) The number of alveoli in the terminal respiratory unit of man during late intrauterine life and childhood. Arch Dis Child, 35 544-547. 

At the terminal point of the airways, the terminal bronchiole becomes the acinus, or the respiratory unit, of the lung. The acini vary in size but in general contain several generations of respiratory bronchioles (bronchioles that have alveolar sacs directly opening to their lumen), which lead to alveolar ducts and ultimately alveolar sacs. Connective tissue lines the airways and forms septa that separate acinus from acinus. Collateral ventilation can occur, however, between acini through the pores (the pores of Kohn) that are located in the adjacent alveolar walls. 

Morphologically, emphysema is associated with a destruction of the alveolar septum, which results in a dilation and consequent enlargement of the alveolar spaces (Fig. 19). This is apparently caused by a breakdown of the interstitial connective tissue proteins (primarily elastin) that provide the major structural framework of the lung parenchyma. Two types of emphysema have been defined on the basis of the types of destruction of the alveolar septa observed and the type of dilation of the terminal respiratory unit (the acini) that is observed. A typical acinus branches from a terminal bronchiole and consists of the respiratory bronchioles that have alveolated walls and lead to the alveolar ducts and ultimately to the alveolar sacs (see Fig. 3). In centrilobular (or centriacinar) emphysema, the sites of degradation and dilation are limited to the region of the terminal and respiratory bronchioles. In panlobular (or panacinar) emphysema, the entire acinus (including the alveolar ducts and sacs) is more uniformly affected. 

In confined spaces it is necessary to keep the concentration of CO from automobile exhaust down to acceptable limits. Therefore, CO infrared gas analyzers have been installed on a large scale in such places (e.g., tunnels, parking areas, etc.). In medicine, respiratory units for lung-function investigations have used infrared analyzers. The use of infrared methods for qualitative and quantitative information on a variety of gases and vapors has been discussed earlier in this chapter in connection with anesthesiology and toxicology applications. 

Staffing Support of mobile teams to reduce high workloads international recruitment of nurses enhancement of medical staff clinical receptionists coaching of new staff implementation of two night shifts on geriatric, oncology and respiratory units additional administrative support for nursing care... 

Figure 23.1 Division of conducting airways and terminal respiratory units.

Figure 18. Prognssive subdivision of the tracheobronchial tree, iOustrudng both conducting ainM s and the respiratory unit.

Table 5 Distribution of 68 Respiratory Units According to the Three Levels of Care...

In May 2002, Vianna et al. (9) evaluated LTV in patients with a stay >30 days, in 77 ICUs in Rio de Janeiro, noting by telephone interview that 26 were publicly funded and 51 were in the private system. There were 645 patients of whom 62 (9.6%) met the criteria for prolonged stay. The main causes were pulmonary and neurological illness. Invasive ventilation was used in 93% of public and 79% of private units. Noninvasive ventilation was not registered in public units, but used in 12% of private patients. The authors noted that noninvasive positive pressure ventilation (NIPPV) in specialized respiratory units would reduce costs as well as length of stay in the ICU. A study conducted by nurses (10) in the ventilator-dependent pediatric population improved the process of family care during their ICU stay and when at home. 

NICOLINO AMBROSINO is Director of Respiratory Unit, Cardio-Thoracic Department, University Hospital of Pisa, Italy, Director of Pulmonary Rehabilitation and Weaning Center, Volterra, Italy and is or was Professor at the Universities of Pisa, Pavia, Florence, and Trieste, Italy. Professor Ambrosino s research and clinical activity has been devoted to Respiratory Critical Care, Pulmonary Rehabilitation and Home Respiratory Care. He contributed to the development of the use of non-invasive mechanical ventilation techniques in acute and chronic respiratory failure, with several clinical trials and original experimental studies. Results of his studies have been published in more than 155 peer-reviewed international journals. The former Head of Pulmonary Rehabilitation Working Croup of the European Respiratory Society (ERS), Dr. Ambrosino is a member of various editorial boards of several international journals, has written over 60 books and chapters, 200 articles, and has spoken at over 100 international conferences. 

It is good practice to keep concentrations of airborne nickel in any chemical form as low as possible and certainly below the relevant standard. Local exhaust ventilation is the preferred method, particularly for powders, but personal respirator protection may be employed where necessary. In the United States, the Occupational Safety and Health Administration (OSHA) personal exposure limit (PEL) for all forms of nickel except nickel carbonyl is 1 mg/m. The ACGIH TLVs are respectively 1 mg/m for Ni metal, insoluble compounds, and fume and dust from nickel sulfide roasting, and 0.1 mg/m for soluble nickel compounds. The ACGIH is considering whether to lower the TLVs for all forms of nickel to 0.05 mg/m, based on nonmalignant respiratory effects in experimental animals. 

Potassium superoxide is utilized primarily ia respiratory support equipment. The material is produced ia the United States (Gallery Chemical Company), France (Air Liquide), and China. 

However, there are occasions ia which the use of a respiratory stimulant may be warranted. By far the leading respiratory stimulant marketed ia the United States is doxapram [309-29-5] (13), prepared by a unique rearrangement of the pyrroHdine [3471-97-4] (14) to the pyrroHdinone [3192-64-1] (15), followed by alkylation using morpholine (15). 

Manufacture, Shipment, and Analysis. In the United States, sodium and potassium thiocyanates are made by adding caustic soda or potash to ammonium thiocyanate, followed by evaporation of the ammonia and water. The products are sold either as 50—55 wt % aqueous solutions, in the case of sodium thiocyanate, or as the crystalline soHds with one grade containing 5 wt % water and a higher assay grade containing a maximum of 2 wt % water. In Europe, the thiocyanates may be made by direct sulfurization of the corresponding cyanide. The acute LD q (rat, oral) of sodium thiocyanate is 764 mg/kg, accompanied by convulsions and respiratory failure LD q (mouse, oral) is 362 mg/kg. The lowest pubhshed toxic dose for potassium thiocyanate is 80—428 mg/kg, with hallucinations, convulsions, or muscular weakness. The acute LD q (rat, oral) for potassium thiocyanate is 854 mg/kg, with convulsions and respiratory failure. 

Respiratory Syncytial Virus. Respiratory syncytial vims (RSV) causes severe lower respiratory tract disease in infants. It is the major cause of hospitalization in the United States (- 90,000 events/yr) and it has a high mortaUty rate in neonates and other high risk populations, such as the geriatric population (51). Development of an RSV vaccine has always been a major priority, however, earlier attempts have mostiy failed (70). 

The RDA for niacin is based on the concept that niacin coen2ymes participate in respiratory en2yme function and 6.6 niacin equivalents (NE) are needed per intake of 239 kj (1000 kcal). One NE is equivalent to 1 mg of niacin. Signs of niacin deficiency have been observed when less than 4.9 NE/239 kj or less than 8.8 NE per day were consumed. Dietary tryptophan is a rich source of niacin and the average diet in the United States contains 500—1000 mg of tryptophan. In addition, the average diet contains approximately 8—17 mg of niacin. In total, these two quantities total 16—34 NE daily. Table 5 Hsts the RDA and U.S. RDA for niacin (69). 

Because a filter sample includes particles both larger and smaller than those retained in the human respiratory system (see Chapter 7, Section III), other types of samplers are used which allow measurement of the size ranges of particles retained in the respiratory system. Some of these are called dichotomous samplers because they allow separate measurement of the respirable and nonrespirable fractions of the total. Size-selective samplers rely on impactors, miniature cyclones, and other means. The United States has selected the size fraction below an aerodynamic diameter of 10 /xm (PMiq) for compliance with the air quality standard for airborne particulate matter. 

Formaldehyde has been rated as a possible carcinogen by the United States Occupational Safety and Health Act (OSHA) rules and should be handled with due caution. It is also a strong lacrymator and choking respiratory irritant. It irritates the skin, eyes, and mucous membranes [76]. Since it is used for tanning leather, it is obvious that fonnaldehyde has a high potential for reactions with proteins. Formaldehyde gas is flammable and most formalin solutions contain significant amounts of methanol, which is also volatile, toxic, and flammable. 

Recently, much emphasis has been put on the harmful effects of small particles, i.e., particulate matter (PM), on human health. A number of standards have been established to characterize the PM fractions in the air and their effects on human health. A widely used PM standard in force in both Europe and the United States is based on the mass concentration of particles with a diameter of 10 gm or less (PMjo). However, recently the U.S. Environmental Protection Agency (EPA) proposed a new standard that is based on the aerodynamic diameter of 2.5 gm particles. This new standard emphasizes the significant impact of small particles on human health, especially on the respiratory and cardiovascular systems. 4 ... 

A typical CBA involves a description of the expected decrease in emissions and a model of the impact pathways, such as an estimation of the average damage per emission unit. It involves a valuation of damage units such as loss of 1 kg crop, one person admission to hospital due to respiratory infections, etc. As an example, a part of a result table from a study in determining external environmental costs fot the production of electricity from coaU is shown in Table 15.5. 

A patient who is a recent immigrant to the United Spates is seen in the outpatient clinic for a severe upper respiratory infection. The primary health care provider prescribes a cephalosporin and asks you to give the patient instructions for taking the drug. You note that the patient appears to underhand very little English. Discuss how you would solve this problem. Determine what information you would include in a teaching plan... 

Propofol (Diprivan) is used for induction and maintenance of anesthesia. It also may be used for sedation during diagnostic procedures and procedures that use a local anestiietic. This drug also is used for continuous sedation of intubated or respiratory-controlled patients in intensive care units. 

UNIT V Drugs That Affect the Respiratory System... 

Mr. Potter, age 57 years, is admitted to the pulmonary unit in acute respiratory distress. The primary health care provider orders IV aminophylline. In developing a care plan for Mr. Potter, you select the nursing diagnosis Ineffective Airway Clearance. Suggest Jiursing interventions that would be most important in managing this problem. 

Unit V has three chapters concerning drugs that affect the respiratory system. The first chapter in this unit discusses antihistamines and decongestants, the second chapter in the unit covers bronchodilators and antiasthma drugs, and the last chapter of the unit deals with antitussives, mucolytics, and expectorants. 

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