The Dose Of Succinylcholine in Morbid Obesity By Harry Lemmens & Jay Brodsky Anesthesia Dep. In Sanford University School of Medicine,Sanford, Claifornia. Puplished In Anesth & Analg J.2006.

The purpose of This Study is to determine The Appropriate dose of Succinylcholine in Morbidly Obese Patients. Objectives

The Study enrolled 45 Morbidly Obese Patients who were scheduled for Gastric Bypass surgery. Patients with predicted difficult intubation wrere excluded. Methods

In Randomized Double Blind Fashion, Patients were Assigned to One of three Study Groups. Methods

Group 1, Recived 1mg/kg for the Ideal Body weight. Group 2, Received 1mg/kg for the Lean Body weight. Group 3, Recived 1mg/kg for the Total Body weight. Methods

IBW was calculated using the formula IBW=22×H 2. LBW was estimated as 130%IBW Cont.. Methods

An accelerometer was taped to thumb of an immobilized arm and response to ulnar nerve stimulation of the adductor pollicis muscle was Recorded. Cont.. Methods

General Anesthesia was induced with fentanyl 3mcg/kg LBW, propofol 2.5 mg/kg LBW and the lung were ventilated Via Bag and Mask with 100% O 2. Cont.. Methods

Then, SCH doses were given in Identical filled 20 ml syringes for all study groups. Cont.. Methods

The Trachea was intubated when, after two consecutive stimuli, no further decrease in twitch height was observed. Cont.. Methods

Laryngoscopy conditions were scored to Excellent, good or poor, based on The Guidelines Of The Consensus Conference On Good Clinical Research Practice In Pharmacodynamic Studies of Neuromuscular Blocking Agents. Cont.. Methods

Laryngoscopy conditions were rated as Excellent, if laryngoscopy was easy with relaxed jaw and no resistance to the laryngoscopy blade,if the vocal cords were abducted and did not move,if there was no airway reaction and the patient did not move his limbs during intubation. Cont.. Methods

Laryngoscopy conditions were rated as Good, if the jaw was not fully relaxed and if there was slight resistance to the laryngoscopy blade,if vocal cords were not fully abducted or moving, if there was diaphragmatic movement<10s or if there was slight limb movement during intubation. Cont.. Methods

Laryngoscopy conditions were rated as Poor, If there was poor jaw relaxation or if there was active resistance to laryngoscopy, if the vocal cords were closed, if there was diaphragmatic movement >10s or if there was vigorous limb movement during intubation. Cont.. Methods

After intubation general anesthesia maintained with 50% nitrous oxide and isoflurane ( %) in oxygen. Cont.. Methods

The recovery from neuromuscular block was recorded for 20 min, during which,No further Muscle relaxant added. Cont.. Methods

The incidence and degree of fasciculation after SCH administration were recorded and scored as Absent, Mild or Gross Cont.. Methods

Each patient was interviewed postoperatively on Day1 to determine the incidence of Myalgias. Cont.. Methods

The three study groups were comparable with respect to Age, BMI and Gender. Results

Demographic Data Results group3group2group1 46±1044±941±10Age 165±7167±7166±8Height 122±18126±23128±20weight 45±645±546±7BMI Gender(M,F)

There was No difference in the onset time of maximum neuromuscular blockade among groups, almost 90s.But the maximum block was significantly less in group1. Cont.. Results

The maximum block was significantly less in group 1. The recover intervals were significantly shorter in Groups 1 and 2. Cont.. Results

One third of patients in group 1 had poor intubating conditions. In contrast, None of patients in groups 2&3 had poor intubating condition. Cont.. Results

Intubating conditions Cont.. Results Group3Group2Group1 1374Excellent 246Good 045Poor

There were No differences in the incidence or degree of fasciculation among the three groups. Cont.. Results

Also, There were no difference in the incidence of non incisional pain on day 1 postoperatively. No patient in any group experienced moderate or severe nonincesional pain. Cont.. Results

For the average –weight adults, the usual dose of SCH 1mg/kg given on the basis of TBW. In Morbidly Obese patients TBW is much heavier than IBW. Discussion

It is Postulated that morbidly obese patients may have larger absolute SCH dose requirement than average-weight patients. Discussion

Because Level of Plasma pseudocholinesterase activity and volume of extracellular fluid determine the duration of action of SCH and Both factors are increased in Obesity. Cont.. Discussion

Jense et al. demonestrated that apnic morbidly obese patient will desaturate to hypoxemic levels in <3-4m Discussion

Benumof et al. Defined the time to 50% twitch recovery as the time to functional Recovery with regard to arterial hemoglobin desaturation risk. Discussion

Because, recovery to 50%twitch height in the smaller dose group did not occur before 5m, A dose of SCH based on IBW will provide less than Optimal intubating conditions without protecting from Hypoxemia if difficulty is encountered. Discussion

for morbidly obese patient intubation can be achieved by 1mg/kg based on (IBW,LBW or TBW), None of these dosing regimens will provide Both Adequate and safe conditions. Discussion

In Morbidly Obese Patient: For Complete neuromuscular paralysis and Predictable Laryngoscopy conditions, a larger dose of SCH (1mg/kg for TBW) is Recommended. Study Conclusion

The Dose Of Succinylcholine in Morbid Obesity By Harry Lemmens & Jay Brodsky Anesthesia Dep. In Sanford University School of Medicine,Sanford, Claifornia. Puplished In Anesth & Analg J.2006.

وصلى الله وسلم على نبينا محمد وعلى آله وصحبه أجمعين