Control of ventilation

Respiratory acidosis is characterized by a reduced arterial pH, a primary increase in the arterial PaC02 and, when present for sufficient time, a compensatory rise in the HCOf concentration. Because increased C02 is a potent respiratory stimulus, respiratory acidosis represents ventilatory failure or impaired central control of ventilation as opposed to an increase in C02 production. As such, most patients will have hypoxemia in addition to hypercapnia. The most common etiologies of respiratory acidosis are listed in Table 25-6. 

Epidural/Intrathecal administration Limit epidural or intrathecal administration of preservative-free morphine and sufentanil to the lumbar area. Intrathecal use has been associated with a higher incidence of respiratory depression than epidural use. Asthma and other respiratory conditions The use of bisulfites is contraindicated in asthmatic patients. Bisulfites and morphine may potentiate each other, preventing use by causing severe adverse reactions. Use with extreme caution in patients having an acute asthmatic attack, bronchial asthma, chronic obstructive pulmonary disease or cor pulmonale, a substantially decreased respiratory reserve, and preexisting respiratory depression, hypoxia, or hypercapnia. Even usual therapeutic doses of narcotics may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea. Reserve use for those whose conditions require endotracheal intubation and respiratory support or control of ventilation. In these patients, consider alternative nonopioid analgesics, and employ only under careful medical supervision at the lowest effective dose. 

Some patients experience prolonged seizures, defined as a duration greater than 120 to 180 seconds. These patients require continued oxygenation, control of ventilation, and an i.v. bolus of the anesthetic agent (20 to 40 mg methohexital) or diazepam (2.5 to 5 mg) to abort the seizure. 

The techniques for giving anaesthetic dmgs emd the control of ventilation and oxygenation are of great importance, but are outside the scope of this book. 

Since the end result of OP-induced toxicity from lethal doses through inhalation or other routes is asphyxia secondary to respiratory failure, a brief summary of the mechanisms involved in control of ventilation is provided. Although AChEls affect several aspects of respiration, a detailed review of respiratory... 

Poon, C.-S. 1983a. Optimal control of ventilation in hypoxia, hypercapnia and exercise. In B.J. Whipp and D.M. Wiberg (Eds.), Modelling and Control of Breathing, pp. 189-196, New York, Elsevier. Poon, C.-S. 1983b. Optimality principle in respiratory control. Proceedings of die Second American Control Conference, pp. 36-40. 

Young, D.L. and Poon, C.-S. 1998. Hebbian covariance learning a nexus for respiratory variabUity, memory, and optimization In R.L. Hughson, D.A. Cunningham, and J. Duflin (Eds.), Advances in Modeling and Control of Ventilation, pp. 73 3, New York, Plenum. 

To provide stable operating conditions in its pipe-reactor process, Uhde of Dortmund developed a computer program, which has shown the followir measures to be effective control of ventilation air in the granulator, a separate liquid circuit for the granulator scrubber, an oversized granulating drum, and use of liquid ammonia in the pipe reactor [17]. 

The finest particles (<600 xm) are hard to handle, cake easily, and have the least commercial value. They often are used for maintenance inside the mine, as in road building and repair, and to build temporary barriers. The latter often are erected between pillars for control of ventilation. 

One of the potential advantages of metal stents over the plastic tube stents is the possibility of placement under conscious sedation by flexible endoscopy or fluoroscopy only. However, for a safe and durable access to the tracheobronchial system, the possibility for fine adjustments of the inserted stents, additional therapeutic measures, and permanent control of ventilation, most interventionists prefer to carry out stent implantations under general anesthesia and with the use of a rigid ventilating bronchoscope. Such a setting enables high frequency Venturi jet ventilation. 

The scope of the application of adaptronic structures or systems can be restricted as the spectrum of influential scientific disciplines. Almost each scientific field covers applications, whose technical benefit and business management utility can be improved by realizing adaptronic concepts. While the need for efficient multifunctional materials certainly originates in the high-technology area, the scope of application is by no means exclusively confined to this field. For example, multifunctional adjusting elements of shape memory alloys are successfully applied for the automatic control of ventilation flaps in greenhouses. 

Explain the control of ventilation in a healthy person at sea level breathing air. 

Okubo S, Mortola JR Control of ventilation in adult rats hypoxic in the neonatal period. Am J Physiol 1990 259 R836-R841. 

Schwieler GH. Respiratory regulation during postnatal development in cats and rabbits and some of its morphological substrates. Acta Physiol Scand Suppl 1968 304. Rigatto H. Control of ventilation in the newborn. Annu Rev Physiol 1984 46 661-667. Ackland GL, Noble R, Hanson MA. Red nucleus inhibits breathing dining hypoxia in neonates. Respir Physiol 1997 110 251-260. 

Weil J. Control of ventilation in chronic hypoxia role of peripheral chemoreceptors. In Lahiri S, Cherniak N, Fitzgerald R, eds. Response and Adaptation to Hypoxia Organ to Organelle. New ybrk Oxford University Press, 1991 122-132. 

Smatresk NJ, Cameron JN. Respiration and acid-hase physiology of the spotted gar, a himodal breather. III. Response to a transfer fiom fiesh water to 50% sea water, and control of ventilation. J Exp Biol 1982 96 295-306. 

Infants and children may require long-term ventilatory support due to three categories of diseases that may impair the ventilatory balance increased respiratory load (due to intrinsic cardiopulmonary disorders, upper airway abnormalities, or skeletal deformities), ventilatory muscle weakness [due to neuromuscular diseases (NMD) or spinal cord injury], or failure of neurological control of ventilation (with central hypoventilation syndrome being the most common presentation) (Fig. 1). 

JH Comroe. Human Control of Ventilation. Chicago Yearbook Medical,... 

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