Circulatory, respiratory and metabolic changes after thigh tourniquet release in combined epidural‐propofol anaesthesia with preservation of spontaneous respiration

Abstract

Twelve elderly patients undergoing total knee arthroplasty received lumbar epidural anaesthesia and propofol infusion at 5 mg.kg(-1).h(-1) following a 1.5-2.0 mg.kg(-1) bolus dose with preservation of spontaneous respiration via a laryngeal mask airway. Circulatory, respiratory and metabolic variables were measured before and 1, 3, 5, 15 and 30 min after release of a pneumatic thigh tourniquet. The blood pressure was decreased at all time-points and the respiratory rate increased at 1 min. The P(a)CO(2) was increased only at 1 min. Arterial blood pH and base excess were decreased at 1 and 3 min and 1, 3 and 5 min, respectively. Arterial blood lactate levels were increased at all times. These characteristics were considered to be identical to those under regional anaesthesia with conscious spontaneous respiration, showing that spontaneous respiration under this anaesthetic regimen has a similar respiratory capacity to that of conscious spontaneous respiration.

Exacerbation of myasthenia gravis after tourniquet release

“…None of several case reports of spinal and epidural anesthesia for patients with myasthenia gravis involved a surgical procedure using a tourniquet [1][2][3][4][5][6]. Several studies have shown that after the release of thigh tourniquets, arterial blood lactate concentrations increase [16][17][18] and remain increased for at least 30 minutes [16]. Longer tourniquet times and bilateral tourniquets increase the amount of lactate released [19].…”

Effective dose of dexmedetomidine as an adjuvant sedative to peripheral nerve blockade in elderly patients

“…Moreover, a thigh tourniquet was applicated before incision and dexmedetomidine infusion. Since BP increased gradually during tourniquet application,29 it could in part alleviate the BP lowering effect induced by dexmedetomidine.…”

Assessment of psychological tension after premedication by measurement of salivary chromogranin A

“…Cephalad placement at 7 cm is our regimen to prevent catheter migration from the epidural space [15]. Thereafter, 8 to 10 mL of 1% ropivacaine was injected epidurally according to our formula for estimating anesthetic spread [16], which was then confirmed by ice packed in a surgical glove that also is our routine regimen [17,18]. The patient was given general anesthesia using propofol alone according to our anesthetic protocol [19][20][21].…”