IngentaConnect Remifentanil and propofol without muscle relaxants or with differ...

Abstract:

Background:

The use of muscle relaxants in outpatient anaesthesia is controversial; some authors recommend an induction regimen including propofol and opioids without muscle relaxants. This study evaluated the requirements for rocuronium after remifentanil/propofol.

Methods:

We examined in four groups of ASA I–II patients (n=30 for each) the intubating conditions three minutes after induction of anaesthesia with remifentanil 0.5 mgr g kg^-1 min^-1, propofol 2 mg kg^-1 without muscle relaxants or with different doses of rocuronium (0.6 mg kg^-1, 0.45 mg kg^-1, 0.3 mg kg^-1) applying the criteria proposed by the Copenhagen Consensus Conference. In the second part of the study the time course of neuromuscular block was determined by electromyography using train-of-four (TOF) stimulation. To this end, another 60 ASA I–II patients were randomly assigned to receive remifentanil 0.5 mgr g kg^-1 min^-1, propofol 2 mg kg^-1 and either rocuronium 0.6 mg kg^-1, 0.45 mg kg^-1, 0.3 mg kg^-1, or 0.3 mg kg^-1 followed by neostigmine 40 mgr g kg^-1 and atropine 20 mgr g kg^-1 at a T1 recovery of 10% (n=15 for each).

Results:

Intubating conditions were good or excellent in 30 patients after rocuronium 0.6 mg kg^-1 and in 18 patients when rocuronium was omitted (P<0.01). After 0.45 mg kg^-1 and 0.3 mg kg^-1 rocuronium the numbers were 29 and 30 patients, respectively. Reducing rocuronium from 0.6 mg kg^-1 to 0.45 mg kg^-1 or 0.3 mg kg^-1 increased the onset time from 136 (35) s to 199 (34) s and 249 (52) s (mean (SD)), (P<0.01); the clinical duration decreased from 38 (10) min to 24 (8) min and 16 (5) min, respectively (P<0.01); and the duration to a TOF-ratio of 0.8 decreased from 60 (11) min to 45 (9) min and 34 (7) min (P<0.01). After rocuronium 0.3 mg kg^-1 this time interval further decreased to 22 (3) min when neostigmine was given at a T1 of 10% (P<0.01 compared with spontaneous recovery after rocuronium 0.3 mg kg^-1).

Conclusion:

After remifentanil/propofol intubation conditions were poor in 40% of patients without muscle relaxants; adding reduced doses of rocuronium to this regimen improved the intubation conditions significantly. In addition, reducing the initial dose of rocuronium markedly shortened its time course of action.

Keywords: Pharmacology, propofol, remifentanil; neuromuscular block, rocuronium; intubation tracheal; pharmacodynamics; antagonists neuromuscular block, neostigmine; monitoring, electromyography

Language: English

Document Type: Original article

Affiliations: Department of Anaesthesia and Critical Care, University of the Saarland, Homburg/Saar, Germany:

Remifentanil and propofol without muscle relaxants or with different doses of rocuronium for tracheal intubation in outpatient anaesthesia