The Effect of Age on the Incidence of Postoperative Residual Neuromuscular Blockade
Condition: Residual Neuromuscular Blockade in Elderly Patients
MeSH terms: Delayed Emergence from Anesthesia
Study type: Observational

Summary: 
      Residual neuromuscular blockade is frequently observed in the early postoperative period when
      patients have received a general anesthetic with muscle relaxants. At the present time it is
      uncertain whether certain patient populations are at greater risk for this common anesthetic
      complication. However, it is possible that elderly surgical patients may exhibit a higher
      incidence of residual neuromuscular blockade. The aim of this clinical trial is to determine
      the incidence of residual neuromuscular blockade in a cohort of younger (ages 18-50) and
      older (ages 70-90) patients undergoing surgery and general anesthesia.
    

Detailed description: 
      300 patients will be enrolled in this study. Patients will be selected for enrollment by
      reviewing the operating room schedule on the day prior to the procedure. Two groups of
      patients will be examined; group 1 will consist of patients ages 18-50 (n=150) and group 2
      will consist of patients age 70-90 (n=150). Patients will be enrolled in blocks of 20 to
      ensure an equal distribution of subjects in each age group over time.

      Anesthetic and neuromuscular management will be standardized in both study cohorts

      Neuromuscular Monitoring:

      On arrival to the PACU, a blinded research assistant will obtain a quantitative TOF
      measurement in all subjects. The TOF-Watch SX will be used to obtain these measurements. Two
      consecutive responses to TOF stimulation (separated by > 15 seconds) will be obtained, and
      the average of the two values recorded. If the measurements differ by greater than 10%,
      additional TOF ratios can be obtained (up to a total of 4 TOF values), and the closest two
      ratios averaged. The number of patients with TOF ratios < 0.7, 0.8, and 0.9 (which are levels
      of residual neuromuscular block associated with various adverse clinical outcomes) in each
      group will be compared.

      Signs and Symptoms of Residual Neuromuscular Blockade After TOF data is collected on arrival
      to the PACU, the patients will be carefully examined for signs and symptoms of muscle
      weakness by a blinded research assistant. A standardized examination form will be used to
      determine the presence or absence of muscle weakness in a variety of muscle groups. The
      examination will be performed on arrival to the PACU and again 15 minutes after admission.

      Respiratory Events Potentially Related to Residual Neuromuscular Blockade

      Pulse oximetry will be used to continuously monitor arterial oxygen saturations (Sp02) during
      patient transport and in the PACU. Patients will be transported to the PACU without
      supplemental oxygen (unless the anesthesia care provider determines that oxygen therapy is
      required for patient safety-per standard practice). All patients will be placed on 2 liters
      nasal cannula oxygen in the PACU. In the PACU, pulse oximetry will be used to continuously
      measure Sp02. Oxygenation data will be stored and recorded every minute for the first 30
      minutes of the PACU admission. In addition to oxygenation data, patients will be assessed
      during transportation to the PACU and during the first 30 minutes of the PACU admission for
      evidence of airway obstruction.

      PACU Length of Stay The impact of age and residual blockade on length of PACU stay will be
      determined. The time required to meet discharge criteria and achieve actual discharge will be
      noted.
    

Intervention name(s): Age and incidence of residual neuromuscular blockade
Intervention type(s): Other
Intervention description(s): An older cohort is anticipated to have a higher incidence of residual neuromuscular blockade
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients undergoing general anesthesia and surgery
      
Keywords: Elderly; Residual neuromuscular blockade