General Plus Spinal Anesthesia and General Anesthesia Alone on Right Ventricular Function

Comparative Effect of Combined High Spinal and General Anaesthesia With General Anaesthesia Alone On Right Ventricular Function In Patients With Mitral Valvular Disease With Pulmonary Hypertension

The investigator hypothesize that High Spinal Anesthesia (HSA) by its effect on attenuation of stress response, decrease in pulmonary vascular resistance, myocardial protection and positive myocardial oxygen balance will cause improvement in right ventricular function. So far there is no study that has evaluated the effect of HSA anesthesia on the right ventricular function, hence the investigator planned this study to compare the effect of HSA on the right ventricular function in patients with mitral valve disease with moderate to severe pulmonary hypertension planned for mitral valve replacement surgery.

All study patients will undergo routine TTE and TEE examination protocol followed at the investigator institution. All the other routine monitoring such as end tidal carbon dioxide, urine output, ABG, ACT, BIS, electrolytes, blood sugar, hemoglobin and ventilatory parameters etc for open heart surgery will be done as per institutional practice. In the study group, the patients will receive spinal anesthesia after placement of invasive lines and prior to induction of GA.In both the study group GA will be induced with midazolam 1-2 mg, fentanyl 2μ/kg and propofol titrated to achieve loss of consciousness. Inj. Vecuronium bromide 0.1mg/kg will be used as muscle relaxant to facilitate tracheal intubation and lignocaine spray (LOX 10% spray, Neon laboratories LTD, Thane, India) will be used over vocal cords prior to intubation to blunt the sympathetic stimulation.

Subsequently anesthesia will be maintained in both the groups, with isoflurane inhalation to maintain BIS values between 40 to 60. In control group, fentanyl infusion 1μ/kg/hr will be started for analgesia, a similar looking infusion without fentanyl will be started in the spinal group.All patients will be shifted to ICU with inotropic and vasopressor support as per the hemodynamic condition.

Inclusion Criteria:

• 50 consecutive patients of 18 to 60 years age,
• NYHA class II or III,
• with mitral valvular disease with moderate to severe PAH (mean pulmonary artery pressure > 40 mmHg) undergoing MVR

Exclusion Criteria:

• emergency or redo surgery, patients with associated CAD or other valvular heart disease,
• COPD,
• bronchial asthma,
• obesity (BMI more than 30), anticipated difficult airway,
• opioid drug abuse or addiction and those with contraindication for spinal anaesthesia including local site infection,
• spinal deformity, deranged coagulogram defined by platelet count < 80,000 & INR > 1.