The number of elderly patients above 80 years is increasing and a large proportion of these patients will require surgery and anesthesia.

During anesthesia neuromuscular blocking agents (NMBA) are administered to facilitate intubating conditions and reduce the trauma to the larynx and vocal cords. There is a risk of residual neuromuscular block when using NMBAs like rocuronium.

The aim of this study is to determine the onset time, duration of action and effect on intubating conditions after rocuronium 0.3 mg/kg and 0.9 mg/kg in patients with age ≥ 80 years.

The number of elderly patients (>80 years) is increasing and a large proportion of these patients will require surgery and anesthesia within the next decades. Elderly patients are at higher risk of major morbidity and mortality and are characterized by a reduction in cardiac output, liver function and renal function. These physiological changes influence pharmacodynamics and pharmacokinetics of drugs administered during anesthesia.

Rocuronium is a nondepolarizing neuromuscular blocking drug with an onset time of approximately 70 s and a clinical duration of action of approximately 50 min. according to previous studies. During anesthesia rocuronium is administered to facilitate intubating conditions and reduce the trauma to the larynx and vocal cords. Rocuronium is primarily metabolized in the liver (70 % unmetabolized via the bile) and excreted via the kidneys.

Onset time and duration of action of rocuronium should be assessed by objective neuromuscular monitoring. Also, this reduces the risk of residual neuromuscular block which is defined as a train of four (TOF) ratio less than 0.9. Especially elderly patients have a high incidence of residual neuromuscular block.

The collected data regarding the effect of rocuronium in elderly patients may change the treatment so these patients receive the correct dose for optimal intubating conditions. Also, detection of duration of action of different doses of rocuronium may reduce the risk of residual block and postoperative respiratory complications

The aim of this study is to determine the onset time, duration of action and effect on intubating conditions after rocuronium 0.3 mg/kg and 0.9 mg/kg in patients with age ≥ 80 years.

Inclusion Criteria:

• Age ≥ 80
• Scheduled to elective surgery (expected duration time of surgery > 1 hour) under general anesthesia with intubation and use of rocuronium.
• American Society of Anesthesiologists (ASA) physical status classification I to III
• Informed consent (see appendix 1)
• Read and understand Danish

Exclusion Criteria:

• Neuromuscular disease
• Known allergy to rocuronium
• Prone position
• Indication for rapid sequence induction