Reliability of pressure cuff induced transient limb ischemia in conscious rabbits

Background The protective effects of transient limb ischemia （TLI） induced by several cycles of intermittent pressure cuff inflation and deflation for a period have been widely investigated,however the reliability of this protocol has not been clearly verified.Our study aimed to investigate the reliability of pressure cuff induced TLI in conscious rabbits.Methods Eight New Zealand rabbits were subjected to TLI without anesthesia.TLI consisted of 3 cycles of ischemia and reperfusion induced by inflating the cuff placed on the left lower limb to 200 mmHg for 5 minutes followed by deflating the cuff for 5 minutes.Skin color,pulse oxygen saturation （SpO2）,pulse rate （PR）,plethysmogram waveform （Pleth）,and ultrasound detection of the blood flow in the extremity distal to the ischemic segment were observed to confirm ischemia and reperfusion during TLI.The frequency of severe limb movement during TLI was also recorded to assess the amenability of this protocol in conscious rabbits.Results The skin color of the extremity distal to the ischemic segment changed from bright red to dark purple after inflating the cuff to 200 mmHg,and returned to normal after cuff deflation.Pleth,PR and SpO2 disappeared during ischemia and restored during reperfusion in the monitor.Blood flow of the left posterior tibial artery was completely blocked by a pressure of 200 mmHg during ischemia,and recovered immediately after cuff deflation.The frequency of severe limb movement in supine position was higher than that in prone position （P〈0.05）,but there was no severe limb movement that could result in disturbance to ischemia when the rabbits were placed in prone position.Conclusion Pressure cuff inflating to 200 mmHg for 5 minutes and deflating for 5 minutes is a reliable regimen to induce TLI in conscious rabbits.

Pressure changes in tapered and cylindrical shaped cuff after extension of head and neck:A randomized controlled trial

BACKGROUND The proper cuff pressure of endotracheal tube(ET)plays an important role in sealing the airway and preventing airway complications during mechanical ventilation.The ET cuff shape affects the cuff pressure after positional change.AIM To investigate cuff pressure between tapered and cylindrical cuff after extension of head and neck during nasal endotracheal intubation.METHODS In a randomized clinical trial,52 patients were randomized to one of two groups:cylindrical cuff or Tapered cuff.Cuff pressure with 22 cmH_(2)O was applied to patients in the neutral position.After extension of head and neck,the cuff pressure was evaluated again and readjusted to 22 cmH_(2)O.In addition,the extent of cephalad migration of ET tip was assessed and postoperative airway complications such as sore throat,and hoarseness were measured.RESULTS The cuff pressure was higher in the tapered cuff(28.7±1.0 cmH_(2)O)than in the cylindrical cuff(25.5±0.8 cmH_(2)O)after head and neck extension(P<0.001).The extent of cephalad migration of tube tip was greater in TaperGuard ET(18.4±2.2 mm)than in conventional ET(15.1±1.2 mm)(P<0.001).The incidence of postoperative airway complications was comparable between two groups.CONCLUSION After head and neck extension,the cuff pressure and the extent of cephalad migration of ET was greater in tapered cuff than in cylindrical cuff during nasal intubation,respectively.