Hypotension during anesthesia often occurs because reduced systemic vascular resistance and blocked sympathetic nervous system by anesthetic drugs. In patients who are taking hypertension medication, blood pressure drops are exaggerated by inadequate compensation mechanism due to decrease of blood vessel elasticity and desensitization of baroreceptors. In one-lung ventilation (OLV) during thoracic surgery, persistent perfusion of non-ventilatory lungs can lead to increased intra-pulmonary shunt and hypoxemia. As a compensatory mechanism, the gravitational effect and hypoxic pulmonary vasoconstriction occur. Among these, hypoxic pulmonary vasoconstriction is associated with pulmonary vascular resistance. Norepinephrine and vasopressin, which are commonly used in patients with hypotension, affect systemic and pulmonary vascular resistance. However, no studies have been done on lung oxygenation and pulmonary mechanics of these vasoactive drugs in patients undergoing surgery on one lung. Therefore, the purpose of this study is to investigate the effects of vasoactive drugs, norepinephrine and vasopressin, in patients with hypertension.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
40
In group N, 16 mcg / cc of norepinephrine was infused through the central catheter. Drug titration should be 0.05 mcg / min / kg for norepinephrine and 2 units / hr for vasopressin, until target blood pressure is reached. Drug infusion rate should not exceed 0.3mcg / min / kg for norepinephrine and 10unit / hr for vasopressin for patient's safety.
In group V, 0.4 unit / cc of vasopressin was infused through the central catheter and the respective doses recorded. Drug titration should be 0.05 mcg / min / kg for norepinephrine and 2 units / hr for vasopressin, until target blood pressure is reached. Drug infusion rate should not exceed 0.3mcg / min / kg for norepinephrine and 10unit / hr for vasopressin for patient's safety.
Department of Anaesthesiology and Pain Medicine, Anaesthesia and Pain Research Institute, Yonsei University College of Medicine
Seoul, South Korea
RECRUITINGPaO2/FiO2 ratio
(arterial oxygen partial pressure / fractional inspired oxygen) at the time of T2
Time frame: about 20 minutes after reaching to the target blood pressure (T2)
lung mechanics: lung compliance
Compliance= tidal volume/plateau airway pressure (ml/mmHg)
Time frame: about 20 minutes after reaching to the target blood pressure (T2)
lung mechanics: dead space
dead space = \[(PaCO2 - PetCO2)/PaCO2\] \* Tidal volume (ml)
Time frame: about 20 minutes after reaching to the target blood pressure (T2)
lung mechanics: airway pressure
airway pressure at T2 (mmHg)
Time frame: about 20 minutes after reaching to the target blood pressure (T2)
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