Propofol respiratory effects

Both alfentanil and propofol were effective and safe, provided respiratory and cardiovascular parameters were routinely monitored. 

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. 

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... 

Propofol has a remarkably simple structure resembling that of phenol disinfectants. Because the substance is water-insoluble, an injectable emulsion is prepared by means of soy oil, phosphatide, and glycerol. The effect has a rapid onset and decays quickly, being experienced by the patient as fairly pleasant. The intensity of the effect can be well controlled during prolonged administration. Possible adverse reactions include hypotension and respiratory depression, and a potentially fatal syndrome of bronchospasm, hypotension, and erythema. 

Propofol infusion syndrome mimics the mitochondrial myopathies, in which there are specific defects in the mitochondrial respiratory chain. The clinical features of mitochondrial myopathy result from a disturbance in lipid metabolism in cardiac and skeletal muscle. These patients generally remain well until stressed by infection or starvation, although subclinical biochemical abnormalities of mitochondrial transport can be demonstrated. It has been suggested that early management of critically iU children may not include adequate calorific intake to balance the increase in metabolic demands, and that in susceptible children the diversion of metabolism to fat substrates may cause the propofol infusion sjmdrome. It is unclear if the dose or duration of propofol infusion alters this effect. As adults have larger carbohydrate stores and require lower doses of propofol for sedation, this may account for the relative rarity of the sjmdrome in adults. The authors suggested that adequate early carbohydrate intake may prevent the propofol infusion syndrome (71). 

In two randomized, double-blind, controlled comparisons of anesthetic techniques for extracorporeal shock wave lithotripsy remifentanil infusion had no advantage over the combination of fentanyl bolus plus propofol infusion, but caused more adverse effects (nausea and vomiting) (10). In another study remifentanil infusion provided comparable analgesia and caused less respiratory depression and fewer gastrointestinal symptoms than intravenous boluses of sufentanil (11). 

The respiratory depressant and gastrointestinal adverse effects of remifentanil have been observed in a randomized, single-blind study of 125 patients undergoing elective orthopedic and urological surgery under spinal or brachial plexus anesthesia (16). They were randomized to either remifentanil (a bolus of 0.5 micrograms/kg plus an infusion of 0.1 micrograms/kg/minute) or propofol... 

Tomasic M, Mann L S, Soma L R 1997 Effects of sedation, anesthesia and endotracheal intubation on respiratory mechanics in adult horses. American Journal of Veterinary Research 58 641-646 Trapani G, Altomare C, Liso G et al 2000 Propofol in anesthesia. Mechanism of action, structure-activity relationships, and drug delivery. Current Medicinal Chemistry 7 249-271... 

Propofol is extremely hpid soluble and has a large volume of distribution. It has a very rapid onset of action and an extremely short half-life (2 to 4 minutes), which promotes rapid awakening on drug discontinuation. Although extensive data are not available, it appears to be effective in GCSE. " Doses can be found in Table 55-4. It may cause respiratory and cerebral depression and bradycardia. Although metabolic acidosis has been reported, the occurrence of propofol-associated metabolic acidosis is controversial. Finally, a normal adult dose may provide over 1000 calories per day as lipid at a cost to the patient that may exceed 1000 per day. 

Murphy PG, Ogilvy AJ, Whiteley SM. The effect of propofol on the neutrophil respiratory burst. Eur. J Anesthesiol 1996 13 471-3. 

A. Additive effect with other CNS depressants that may result in lower propofol dosage requirements if given concomitantly. Through its inhibition of cytochrome P-450, propofol may increase levels of midazolam, diazepam, and other opiates such as sufentanyl and alfentanyl, causing respiratory depression, bradycardia, and hypotension. 

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