Small Doses Muscle Relaxant in General Anesthesia

Not Applicable

Recruiting

Interventions: Drug: Atracurium Besylate regular dose
Drug: Atracurium Besylate minial dose

Brief Summary: This study will be held to assess the effect of minimal dose muscle relaxant on postoperative pulmonary function. The time to extubation in minutes will be the primary outcome as a clinical indicator of the return of muscle power. The extubation time will be defined as the time from injecting the muscle relaxant reversing agent given when regain the train of four (TOF) ratio to 0.9 till removal of endotracheal tube.

Intraoperative surgical conditions will be assessed in the form of surgeon satisfaction and the need for more muscle relaxant boluses. Postoperative complications as desaturation (peripheral oxygen saturation (Spo2) less than 90%), the need for re-intubation or ventilation support will be recorded. Patient lung will be assessed using ultrasound-based lung aeration score. Also, the diaphragmatic and intercostal muscle function will be assessed in the early postoperative period. Immediate postoperative pulmonary function tests will be evaluated using simple spirometer. Patients will be followed up for 28 days for detection of pulmonary complications.

Detailed Description: After arrival to the operating theater, a thoracic US examination will be done using LUS dynamic re-aeration score. Patients will be randomly allocated via sealed opaque envelopes into 2 groups of 30 patients each; control (C) group and minimal dose (Min) group.

For general anesthesia; intubating dose of muscle relaxant will be injected according to the study group; in C group; atracurium 0.5 mg/kg while in min group 0.2 mg/kg will be injected. The trial for intubation will be assessed and recorded. Train-of-four (TOF) stimulation will be maintained less than 2 throughout the intraoperative period in the control group. While, in the min group, boluses of muscle relaxant will be given only upon complain of the surgeon and after a bolus dose of propofol 0.5 mg/kg. When required, 20% of the initial dose of muscle relaxant will be provided as a bolus to achieve this goal.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

American Society of Anesthesiologists (ASA) score more than 3
suspected full stomach or who will undergo intervention expected to necessitate profound muscle relaxation or dressing interferes with ultrasound (US) probe positioning
Lung parenchymatous disease
renal disease
hepatic disease
neuromuscular disease
electrolytes imbalanc
on medication interfere with muscle contraction
with known allergy to any drug used in the study

Arm && Interventions

Group	Intervention	Description
control (C) group	Atracurium Besylate regular dose	Intubating dose of muscle relaxant will be atracurium 0.5 mg/kg Maintenance doses of muscle relaxant will be given throughout the intraoperative period to maintain the Train-of-four values continuously less than 2
minimal dose (M) group	Atracurium Besylate minial dose	Intubating dose of muscle relaxant will be 0.2 mg/kg will be injected boluses of muscle relaxant will be given only upon complain of the surgeon and after a bolus dose of propofol 0.5 mg/kg. When required, 20% of the initial dose of muscle relaxant will be provided as a bolus to achieve this goal.

Primary Outcome Measures

Name	Time	Method
The time to extubation in minutes	after injecting the muscle relaxant till removal of the tracheal tube	the time from injecting the muscle relaxant reversing agent given when regain the train of four (TOF) ratio to 0.9 till removal of endotracheal tube

Secondary Outcome Measures

Name	Time	Method
Total doses of propofol used in M group post-induction	intraoperatively	a bolus dose of propofol 0.5 mg/kg given in the M group, upon complain of the surgeon and before boluses of muscle relaxant
lung aeration via Lung ultrasound dynamic re-aeration score	basal immmediate preoperative & with first 30 minutes postoperative	0= normal aeration (horizontal A-lines or ≤ 2 B-lines); 1 = moderate loss of aeration (multiple B-lines, either regularly spaced (7 mm apart), or irregularly spaced and even coalescent but only visible in a limited area of the intercostal space); 2 = loss of aeration (multiple coalescent B-lines, in prevalent areas of the intercostal spaces and observed in one or several intercostal spaces); 3 = complete loss of aeration (lung consolidation, with or without air bronchograms)
first Postoperative day complications	after removal of the tracheal tube and for 24 hours postoperative	desaturation (Spo2 less than 90%), need for re-intubation, need of ventilation support
Time to the first intraoperative need of muscle relaxant bolus (Atracurium), in the M group	Given intraoperatively only upon complain of the surgeon and after a bolus dose of propofol 0.5 mg/kg	blouse of muscle relaxant given only upon complain of the surgeon and after a bolus dose of propofol 0.5 mg/kg

Locations (1): Mansoura University-Emergency hospital-ICU
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Mansoura, Egypt