Propofol dosing

Propofol dose-dependently reduced the threshold for lidocaine-induced convulsions in rats (82). Higher doses of propofol completely abolished convulsions. However, there was no difference in the dose of lidocaine that caused cardiac arrest and death, when it was given with three different propofol infusions and placebo. 

In a subsequent retrospective cohort analysis the odds ratio for the propofol infusion syndrome was 1.93 (95% Cl = 1.12, 3.32) for every 1 mg/kg/hour increase in mean propofol dose above 5 mg/kg/hour. The authors suggested that propofol infusion at rates over 5 mg/kg/hour should be discouraged for long-term sedation. 

Wilder-Smith OHG, Ravussin PA, Decosterd LA, De land PA, Bissonnette B Midazolam premedication reduces propofol dose requirements for multiple anesthetic en %M>ints CanJ Anesth(200 )4Z, 439-45... 

Hollman GA, Schultz MM, Eickhoff JC, Christenson DK. Propofol-fentanyl versus propofol alone for lumbar puncture sedation in children with acute hematologic malignancies propofol dosing and adverse events. Pediatr Crit Care Med 2008 9(6) 616-22. 

Propofol infusion syndrome has been described and may result in severe metabolic acidosis, cardiac dysrhythmias, cardiovascular collapse, rhabdomyolysis, and death. The risk may be increased with concomitant catecholamine infusions or when the dose exceeds... 

Propofol 5-20 mcg/kg/min continuous IV infusion (in patients who require frequent neurological assessment) Reassess goals daily and titrate/taper dose to desired response (as patients may accumulate the medication or become tolerant)... 

The anesthetic agent propofol can be started with loading doses of 1 mg/kg repeated every 3 to 5 minutes until a clinical... 

Pentobarbital is commonly loaded at a dose of 10 to 15 mg/kg over 1 to 2 hours, followed by a continuous infusion of 0.5 to 4 mg/kg per hour. Therapy can be tapered off after 12 to 24 hours of seizure control as evident on the EEG.35 One metaanalysis reported a lower incidence of treatment failure with pentobarbital (3%) when compared to midazolam (21%) or propofol (20%), although the risk of hypotension requiring vasopressor therapy was higher when pentobarbital was used.36 This relative efficacy for pentobarbital must be considered... 

General anesthesia - Remifentanil is not recommended as the sole agent in general anesthesia because loss of consciousness cannot be assured and because of a high incidence of apnea, muscle rigidity, and tachycardia. Remifentanil is synergistic with other anesthetics and doses of thiopental, propofol, isoflurane, and midazolam have been... 

Propofol can be used for induction as well as maintenance of anesthesia. It is very lipophilic and induction of anesthesia takes place within 30 seconds. After a single dose the patient awakes in approximately 5 minutes and after anesthesia by continuous intravenous administration of longer duration recovery may take 10-15 minutes. It can be used in combination with the usual range of premedications, analgesics, muscle relaxants and inhalation anesthetic agents. 

Propofol is primarily a hypnotic drug with substantial cardiorespiratory depressant actions and with no ability to produce neuromuscular blockade. While propofol lacks analgesic properties, its use permits lower doses of opioids. Likewise, less propofol is required for adequate hypnosis when it is administered with opioids. Thus, it is said that propofol and opioids interact synergistically. 

The dose of propofol should be reduced in older patients however, it does have a relatively linear dose-response characteristic, and patients generally can be... 

Answer This feature of bradycardia is typical of patients who take (3-blockers, which should be continued so they result ultimately in better anesthetic management. The drugs given could have been modified (i.e., etomidate instead of propofol, which does not raise or may cause a slower heart rate). The potent opioids in the fentanyl family all cause vagal transmitted bradycardia. The muscle relaxant vecuronium (norcuron) has no effect on heart rate and could have been replaced by pancuronium, which has a vagolytic effect and will counter bradycardia in the usual induction bolus doses. 

Unconsciousness is usually achieved 20-40 seconds after an induction dose. Transfer to the CNS is slower than with thiopentone and there is a delay in disappearance of the eyelid reflex, normally used as a sign of unconsciousness after administration of other intravenous anaesthetics. Overdosing of propofol may occur if this sign is used loss of verbal contact is a more reliable end-point. 

The use of propofol is associated with a feeling of well-being during early recovery and nausea and vomiting is less common in the postoperative period than with some other intravenous agents. Subanaesthetic doses of propofol have been used to treat early postoperative nausea and emesis. Cardiovascular system... 

In healthy patients, propofol produces a greater reduction in systemic blood pressure than equivalent doses of barbiturates. This hypotension is a consequence of both direct and indirect effects, namely, direct myocardial depression. 

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. 

Resuscitation from bupivacaine cardiovascular toxicity is extremely difficult even for experienced clinicians. Recent studies suggest that propofol can be useful in resuscitating patients acutely exposed to toxic levels of bupivacaine. The (S)-isomer, levobupivacaine, appears to have a lower propensity for cardiovascular toxicity than the racemic mixture or the (7 >isomer and has been approved for clinical use. The clinical effects of ropivacaine are similar to those of bupivacaine, but ropivacaine is allegedly associated with a lower potential for cardiovascular toxicity. Ropivacaine is available only as the ( SJ-stereoisomer, which has inherently less affinity for the cardiac sodium channel. However, both cardiac toxicity and CNS toxicity have been reported when large doses of ropivacaine were used for peripheral nerve blocks. 

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