Anesthesia/anesthetics respiratory effects

Administration Nalbuphine should be given as a supplement to general anesthesia only by persons specifically trained in the use of IV anesthetics and management of the respiratory effects of potent opioids. 

Hughes PJ, Doherty MM, Charman WN (1993) A rabbit model for the evaluation of epidurally administered local anaesthetics. Anaesth Intens Care 21 298-303 Ide T, Okitsu Y, Nehashi S et al. (2001) The effect of epidural anesthesia on respiratory distress induced by airway occlusion in isofluorane anesthetized cats. Anesth Analg 92 749-754... 

In the horse, induction with thiopental usually results in a brief increase in heart rate and a decrease in cardiac output but no significant change in arterial blood pressure. Arterial blood pressure is typically lower after thiopental induction than in ketamine-based anesthetic techniques (Bennett et al 1998, Muir et al 2000). However, when horses are placed on inhalation anesthetics for maintenance of anesthesia, the hemodynamic effects of the induction agents is short lived and the hypotension and reduced cardiac output typical of inhalation anesthesia predominates (Bennett et al 1998, Wagner et al 1996). Respiratory depression is significant with an accompanying increase in Paco2 and decrease in pH. 

Ethyl ether (diethyl ether [CAS 60-29-7]) Vapors irritating to eyes and respiratoiy tract. A CNS depressant and anesthetic agent tolerance may develop to this effect. Overexposure produces nausea, headache, dizziness, anesthesia, and respiratory arrest. Evidence for adverse effects on fetal development in test animals. ... 

Respiratory drive and rhythm are depressed by barbiturates. Coughing, sneezing, hiccupping, and laryngospasm may occur during anesthesia with barbiturates. Sedative ot hypnotic doses of barbiturates teduce heatt tate and blood pressure to levels found in normal sleep. Anesthetic doses produce more pronounced effects. Barbiturates cross the placenta when used in labor, they can cause respiratoty depression in neonates. Anesthetic doses dectease force and frequency of uterine contractions among pregnant women. 

The most common use of NjO is in combination with the more potent volatile anesthetics. It decreases the dosage requirement for the other anesthetics, thus lowering their cardiovascular and respiratory toxicities. For example, an appropriate anesthetic maintenance tension for N2O and halothane would be N2O 40% and halothane 0.5%. With this combination in a healthy patient, anesthesia is adequate for major surgery, and the dose-dependent cardiac effects of halothane are reduced. 

Etomidate is a carboxylated imidazole that can be used for induction of anesthesia in patients with limited cardiovascular reserve. Its major advantage over other intravenous anesthetics is that it causes minimal cardiovascular and respiratory depression. Etomidate produces a rapid loss of consciousness, with minimal hypotension even in elderly patients with poor cardiovascular reserve. The heart rate is usually unchanged, and the incidence of apnea is low. The drug has no analgesic effects, and coadministration of opioid analgesics is required to decrease cardiac responses during tracheal intubation and to lessen spontaneous muscle movements. Following an induction dose, initial recovery from etomidate is less rapid (< 10 minutes) compared with recovery from propofol. 

Respiratory depression becomes an important side-effect when opioids are used for postoperative pain treatment, since the anesthetic agent and most adjuncts of anesthesia induce a long-lasting depressant effect on respiration, which can increase the opioid effects up to respiratory arrest. Therefore careful supervision of respiration during the postoperative period is mandatory (Mulroy, 1996). Opioid-induced respiratory depression can be interrupted by the opioid antagonist naloxone. 

Finally, newer intravenous anesthetics such as etomidate (Amidate) and propofol (Diprivan) are available. Etomidate is a hypnoticlike drug that causes a rapid onset of general anesthesia with a minimum of cardiopulmonary side effects. Flence, this drug may be useful in patients with compromised cardiovascular or respiratory function. Propofol is a short-acting hypnotic that is useful as a general anesthetic in some... 

Phencyclidine (PCP) was developed in late 1950 as an intravenous anesthetic agent. PCP produces anesthesia and analgesia with respiratory or cardiovascular depression. However, postoperatively, the drug produced psychotomimetic effects (e.g., delirium and hallucinations) and was subsequently withdrawn from the market. 

In 1958, phencyclidine (PCP) was introduced into clinical anesthesia as an injectable anesthetic agent. PCP had physiological properties that made it a useful anesthetic. The most significant of these was that it was quite effective but had no risk of cardiac or respiratory depression, as was typical of classical general anesthetic agents. 

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