Clinical and Experimental Circulation
Background: Life-threatening cardiovascular events under anaesthesia are uncommon. However, intra-operative dysrrhythmias affect many patients undergoing non-cardiac surgery1. We report a successful intraoperative treatment of a regular supraventricular tachycardia (SVT) with a Valsalva like maneuver carried on by ventilator.
Case report: Female patient, 42 years old, 60kg, ASA I, was admitted for elective tympanoplasty. The patient was pre-treated with 2mg of midazolam and monitored according to ASA standards. We performed a balanced anesthesia with fentanyl (3μ/kg), propofol (3mg/kg) and rocuronium (0.6mg/kg) as induction. Anesthetic maintenance with sevoflurane. Fifteen minutes after induction and before surgical incision the patient developed a regular SVT with a maximum heart rate of 155 bpm without changes in blood pressure. A Valsalva like maneuver was performed using the ventilator with mechanical ventilation initially applying PEEP 30cmH2O and maintained for about 15 seconds. When it was suddenly withdrawn PEEP and heart rate decrease to 130bpm. After this, we switched to spontaneous ventilation, placing the APL valve at 40 cm H2O and sustained the balloon compressed for about 15 seconds. After this maneuver there was a gradual decline in heart rate up to 88 bpm. The patient maintained hemodynamic stability (rhythmic and blood pressure) and therefore was decided to proceed with the surgery, which took place without any complications.
Discussion: If the patient is haemodynamically stable, the initial management of regular SVT should include vagal maneuvers2. In anesthetized patients, without access to the carotid sinus, pharmacological treatment is often the first choice in SVT. However, the Valsalva maneuver induces a temporary slowing of sino-atrial nodal activity and atrio-ventricular nodal conduction by stimulating baroreceptors in the aorta, which triggers a reflex increase in vagus nerve activity and sympathetic withdrawal. With increasing PEEP and balloon compression we can stimulate aortic baroreceptors simulating a Valsalva maneuver. Additionally, we believe that Bainbridge reflex took place too, with initial high PEEP applied.
1. Circulation. 2007;116:e418-e500
2. Resuscitation. 2010; 81:1219-76
Learning points: A Valsalva like maneuver using the ventilator in anesthetized patients may be effective in treating regular SVT in the intraoperative setting.