Minati Choudhury

Early goal-directed therapy in moderate to high-risk cardiac surgery patients

Early goal-directed therapy is a term used to describe the guidance of intravenous fluid and vasopressor/inotropic therapy by using cardiac output or similar parameters in the immediate post-cardiopulmonary bypass in cardiac surgery patients. Early recognition and therapy during this period may result in better outcome. In keeping with this aim in the cardiac surgery patients, we conducted the present study. The study included 30 patients of both sexes, with EuroSCORE >or=3 undergoing coronary artery bypass surgery under cardiopulmonary bypass. The patients were randomly divided into two groups, namely, control and early goal-directed therapy (EGDT) groups. All the subjects received standardized care; arterial pressure was monitored through radial artery, central venous pressure through a triple lumen in the right internal jugular vein, electrocardiogram, oxygen saturation, temperature, urine output per hour and frequent arterial blood gas analysis. In addition, cardiac index monitoring using FloTrac and continuous central venous oxygen saturation using PreSep was used in patients in the EGTD group. Our aim was to maintain the cardiac index at 2.5-4.2 l/min/m2 , stroke volume index 30-65 ml/beat/m2 , systemic vascular resistance index 1500-2500 dynes/s/cm5/m2 , oxygen delivery index 450-600 ml/min/m2 , continuous central venous oximetry more than 70%, stroke volume variation less than 10%; in addition to the control group parameters such as central venous pressure 6-8 mmHg, mean arterial pressure 90-105 mmHg, normal arterial blood gas analysis values, pulse oximetry, hematocrit value above 30% and urine output more than 1 ml/kg/h. The aims were achieved by altering the administration of intravenous fluids and doses of inotropic or vasodilator agents. Three patients were excluded from the study and the data of 27 patients analyzed. The extra volume used (330+/-160 v/s 80+/-80 ml, P=0.043) number of adjustments of inotropic agents (3.4+/-1.5 v/s 0.4+/-0.7, P=0.026) in the EGDT group were significant. The average duration of ventilation (13.8+/-3.2 v/s 20.7+/-7.1 h), days of use of inotropic agents (1.6+/-0.9 v/s 3.8+/-1.6 d), ICU stay (2.6+/-0.9 v/s 4.9+/-1.8 d) and hospital stay (5.6+/-1.2 v/s 8.9+/-2.1 d) were less in the EGDT group, compared to those in the control group. This study is inconclusive with regard to the beneficial aspects of the early goal-directed therapy in cardiac surgery patients, although a few benefits were observed.

Sevoflurane as a sole anaesthetic for thymectomy in myasthenia gravis

Myasthenia gravis is a challenging situation for anaesthesiologists due to its neuromuscular involvement. The main concerns are respiratory muscle weakness and side effects due to a heavy dose of anticholinesterases. This limits the use of sedatives, hypnotics and muscle relaxants. Inhalational anaesthetics are best suited. We describe our experience with sevoflurane as a sole anaesthetic in a child having juvenile‐type myasthenia gravis with thymoma, who underwent thymectomy by midsternal incision. Very smooth and short duration of induction (35 s) and easy intubation within 60 s without use of muscle relaxant were the remarkable features. Sevoflurane in oxygen and nitrous oxide (MAC=0.5–0.7) was used for maintenance of anaesthesia. Recovery was smooth and fast with no residual respiratory insufficiency. Hence we found sevoflurane to be a highly suitable agent for thymectomy in mysthenia gravis.

Prophylactic Vasopressin in Patients Receiving the Angiotensin-Converting Enzyme Inhibitor Ramipril Undergoing Coronary Artery Bypass Graft Surgery

OBJECTIVE The purpose of this study was to compare the effects of continuation versus discontinuation of the angiotensin-converting enzyme (ACE) inhibitor ramipril and assess the efficacy of prophylactic vasopressin infusion on hemodynamic stability and vasoactive drug requirements in patients undergoing coronary artery bypass graft (CABG) surgery. DESIGN A prospective, randomized, double-blinded, single-center clinical study. SETTING Tertiary care hospital. PARTICIPANTS Forty-seven patients on the ACE inhibitor ramipril for 6 weeks before undergoing elective primary CABG surgery on cardiopulmonary bypass (CPB). INTERVENTIONS Patients were randomly divided into 3 groups: group A (n = 16), patients discontinued ramipril 24 hours before surgery; group B (n = 16), patients continued ramipril until the morning of surgery; and group C (n = 15), patients continued ramipril until the morning of surgery and received vasopressin infusion (0.03 U/min) from the onset of rewarming until the hemodynamics were stable without vasopressor agents. The anesthetic technique and conduct of CPB were standardized for all the groups. Hemodynamic parameters and vasoactive drug requirements were recorded for 3 days postoperatively. MEASUREMENTS AND MAIN RESULTS Patients in group A maintained stable mean arterial pressure (MAP) and systemic vascular resistance (SVR). In group B, MAP and SVR decreased after the induction of anesthesia and remained so throughout surgery (p < 0.05). In group C, MAP and SVR decreased upon the induction of anesthesia (p < 0.05) but normalized after CPB. CONCLUSIONS Preoperative ACE inhibitor continuation predisposed to hypotension upon the induction of anesthesia and in the post-CPB period. Prophylactic low-dose vasopressin infusion prevented post-CPB hypotension. Low-dose vasopressin can be considered as potential therapy in these patients.

Inhaled Nitroglycerin Versus Inhaled Milrinone in Children with Congenital Heart Disease Suffering from Pulmonary Artery Hypertension

OBJECTIVE The aim of the present study was to compare the acute effects of inhaled milrinone and inhaled nitroglycerin on pulmonary and systemic hemodynamics in children with acyanotic congenital heart disease (left-to-right shunt) and pulmonary artery hypertension. DESIGN Randomized clinical trial. SETTING Catheterization laboratory of a tertiary care hospital. PARTICIPANTS Thirty-five children below the age of 12 years who were suffering from acyanotic congenital heart disease with left-to-right intracardiac shunt and pulmonary artery hypertension (mean PA pressure > 30 mmHg). INTERVENTION Right-heart catheterization was done using an end-hole balloon wedge pressure catheter. Baseline pulmonary and systemic hemodynamic parameters were recorded for all patients while breathing room air. All patients then underwent pulmonary vasodilator testing with 100% oxygen. Following this, patients were randomized into two groups and received either inhaled milrinone (group M, n = 18) or inhaled nitroglycerin (group N, n = 17) in a 50% air-oxygen mixture. Oximetry data were used to calculate systemic and pulmonary cardiac output based on Ficks principle. RESULTS Systolic, diastolic, and mean pulmonary artery pressures decreased significantly in both the groups after drug nebulization, while there were no significant changes in systemic pressures. The percentage decrease from baseline in systolic (5.2% v 8.6%, p = 0.43), diastolic (19.5% v 16.8%, p = 0.19) and mean (14.9% v14.5%, p = 0.29) pulmonary artery pressures were comparable in both groups. The pulmonary vascular resistance index (PVRI) decreased from 9.0 ± 3.9 to 2.9 ± 1.7 Wood Units (WU)/m(2) in group M (p < 0.001) and from 8.6 ± 3.8 to 3.2 ± 3.3 WU/m(2) in group N (p < 0.001). The fall in pulmonary artery pressures after drug nebulization in both groups was comparable to the fall seen with 100% oxygen. CONCLUSION Both milrinone and nitroglycerin when given via the inhaled route significantly decrease systolic, diastolic and mean pulmonary artery pressures as well as PVRI without significant effects on systemic hemodynamics. Both the drugs given via inhaled route therefore can offer a good therapeutic choice and can help decrease the high inspired oxygen concentrations needed to treat pulmonary artery hypertensive episodes in perioperative settings.

Arterial pressure waveform derived cardiac output FloTrac/Vigileo system (third generation software): comparison of two monitoring sites with the thermodilution cardiac output

The present study was conducted to study the effect of monitoring site, radial or femoral, for arterial pressure waveform derived cardiac output using FloTrac/Vigileo system with third generation software version 3.02 during cardiac surgery. The cardiac output derived from the two sites was also compared to the pulmonary artery catheter (PAC) derived cardiac output to reevaluate the relation between them using the newer software. The effect of cardiopulmonary bypass (CPB) was also studied by doing the sub analysis before and after bypass. Forty patients undergoing coronary artery bypass surgery with cardiopulmonary bypass were enrolled in the study. Cardiac output derived from radial artery (RADCO), femoral artery (FEMCO) using FloTrac/Vigileo system with third generation software version 3.02 and cardiac output using pulmonary artery catheter (PACCO) at predefined nine time points were recorded. Three hundred and forty two cardiac output data triplets were analysed. The Bland–Altman analysis of RADCO and FEMCO revealed a mean bias of −0.28 with percentage error of 20%. The pre CPB precision of both RADCO and FEMCO was 1.25 times as that of PACCO. The post CPB precision of FEMCO was 1.2 times of PACCO while that of RADCO was 1.7 times of PACCO. The third generation of FloTrac/Vigileo system shows good correlation between the radial and femoral derived cardiac outputs in both pre and post bypass periods. The newer software correlates better to PAC derived cardiac output in the post bypass period for femoral artery than radial artery.

A randomized trial of anesthetic induction agents in patients with coronary artery disease and left ventricular dysfunction

The deleterious effects of anesthetic agents in patients suffering from coronary artery disease are well known. The risk increases when a patient has compromised ventricular function. There is a paucity of literature regarding the choice of the suitable agent to avoid deleterious effects in such patients. The use of etomidate and propofol has been considered superior to other intravenous anesthetic agents in these groups of patients. The aim of the present study is to compare the hemodynamic effects of anesthesia induction with etomidate, thiopentone, propofol, and midazolam in patients with coronary artery disease and left ventricular dysfunction. This randomized clinical trail was conducted at the All Indian Institute of Medical Sciences, New Delhi, India. Sixty patients with coronary artery disease and left ventricular dysfunction (ejection fraction < 45%) scheduled for elective coronary artery bypass surgery participated in this study. After stabilization baseline hemodynamic data stroke volume variation and systemic vascular resistance index were recorded for all patients (Flo Trac TM sensor with Vigileo cardiac output monitor used for hemodynamic monitoring). The patients were randomly alloted to one of the four groups and the intravenous induction agent was administered for over 60-90 seconds (Group E--Etomidate 0.2 mg/Kg; Group M--Midazolam 0.15 mg/Kg; Group T--Thiopentone 5 mg/Kg; Group P--Propofol 1.5 mg/Kg). Hemodynamic data were recorded at one minute intervals starting from induction till seven minutes after intubation,--the end point of the present study. There was a significant decrease in the heart rate in comparison to the baseline(-7 to -15%, P = 0.001), mean arterial pressure (-27 to -32%, P = 0.001), cardiac index (-36 to -38%, P = 0.001), and stroke volume index (-27 to -34%, P = 0.001) after induction in all four groups. The hemodynamic response was similar in all the four groups. There was no significant change in central venous pressure and stroke volume variation (SVV) during induction and intubation, while the effects on the systemic vascular resistance index (SVRI) were variable. The midazolam group was the most effective in preventing intubation stress (tachycardia,hypertension). The change from baseline values in heart rate (+ 4%, P = 0.12) and mean arterial pressure (-1%, P = 0.77) after intubation were not statistically significant in the midazolam group. The etomidate group was the least effective of all the four groups in minimizing stress response, with statistically significant increase from baseline in both heart rate (P = 0.001) and mean arterial pressure (P = 0.001) at 1 minute after intubation. All the four anesthetic agents were acceptable for induction in patients with coronary artery disease and left ventricular dysfunction despite a 30-40% decrease in the cardiac index. Clinician experience along with knowledge of the potential interactions (e.g., premedication, concurrent opioid use) is needed to determine hemodynamic stability during anesthetic induction in these patients with ventricular dysfunction.

Parasternal intercostal block with ropivacaine for postoperative analgesia in pediatric patients undergoing cardiac surgery: a double-blind, randomized, controlled study.

OBJECTIVE The objective of this study was to assess the effectiveness of 0.5% ropivacaine used for parasternal intercostal blocks for postoperative analgesia in pediatric patients undergoing cardiac surgery. DESIGN A randomized, controlled, prospective, double-blind study. SETTING A tertiary care teaching hospital. PARTICIPANTS Thirty children scheduled for cardiac surgery with a median sternotomy. INTERVENTIONS A 0.5% ropivacaine injection with 5 doses of 0.5 to 2.0 mL on each side in the 2nd to 6th parasternal intercostal space with a total dose of ropivacaine below 5 mg/kg or the same volume of saline before sternal wound closure. MEASUREMENTS AND MAIN RESULTS The time to extubation was significantly lower in patients administered the parasternal blocks with ropivacaine than in the control group; the mean values were 2.66 hours and 5.31 hours, respectively (p < 0.001). The pain scores were lower in the ropivacaine group compared with the saline group; mean values were 2.20 for the ropivacaine group and 4.83 for the saline group on a scale of 10. The cumulative fentanyl dose requirement over a 24-hour period was higher in the saline group than the ropivacaine group (p < 0.001). CONCLUSIONS Parasternal blocks with ropivacaine appear to be a simple, safe, and useful technique of supplementation of postoperative analgesia in pediatric patients undergoing cardiac surgery with a median sternotomy.

Acute hemodynamic effects of inhaled nitroglycerine, intravenous nitroglycerine, and their combination with intravenous dobutamine in patients with secondary pulmonary hypertension.

OBJECTIVES The presence of pulmonary artery hypertension (PAH) affects the prognosis of patients; therefore, it is important to treat it. The aim of this study is to compare the acute hemodynamic effects of inhaled nitroglycerine (iNTG), intravenous nitroglycerine (IV NTG) alone and their combination with intravenous dobutamine (IV DOB) during the early postoperative period, in patients with PAH undergoing mitral valve or double valve replacement surgery. MATERIALS AND METHODS In the study, 40 patients with secondary PAH were administered iNTG 2.5 microg/kg/min, IV NTG 2.5 microg/kg/min, a combination of iNTG 2.5 microg/kg/min + IV DOB 10 microg/kg/min, and IV NTG 2.5 microg/kg/min + IV DOB 10 microg/kg/min for 10 minutes each following valve replacement surgery, in random order. The hemodynamic parameters were recorded before (T0) and immediately after the intervention. (T1). RESULTS iNTG effectively decreased mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance index (PVRI), and the PVR / SVR ratio, without affecting arterial pressures, systemic vascular resistance or mixed venous oxygen saturation (SvO2). IV NTG produced both systemic and pulmonary vasodilation along with a significant fall in SvO2. The combination of iNTG and IV DOB caused a significant decrease in mPAP and PVRI, with no significant change in SVRI, PVR / SVR ratio, and SvO2. A combination of IV NTG + IV DOB caused both pulmonary and systemic vasodilatation with a significant decrease in SvO2. None of the drugs caused any significant change in the cardiac index. CONCLUSION All drugs were of similar efficacy in reducing the pulmonary vascular resistance index. Only iNTG produced selective pulmonary vasodilatation, while IV NTG and its combination with IV dobutamine had a significant concomitant systemic vasodilatory effect.

Comparison of 48 h and 72 h of prophylactic antibiotic therapy in adult cardiac surgery: a randomized double blind controlled trial

OBJECTIVES To determine whether the duration of antibiotic prophylaxis influences the rate of surgical site infection in patients undergoing coronary bypass grafting or valve replacement. PATIENTS AND METHODS Adult patients undergoing elective coronary artery bypass grafting (CABG) and valve surgery were included in this randomized double blind study. Between April 2007 and April 2008, 235 patients were randomly assigned to one of two groups using random number table and sealed envelope technique. The groups received prophylactic antibiotic therapy for either 48 h (the 48 h group) or 72 h (the 72 h group). These patients were monitored for surgical site infection. RESULTS The mean age was 52.94 +/- 16.30 and 55.27 +/- 16.63 years, respectively, in the two groups. The incidence of co-morbid conditions as well as operative conditions was similar between the groups. During the study period 20 patients developed surgical site infections and 7 patients other infections. In modified treatment analysis, the infection rates were 7.6% (9 patients, n = 119) in the group receiving 48 h of prophylactic antibiotic therapy and 10.2% (11 patients, n = 108) in the group receiving 72 h of prophylactic antibiotic therapy, and the difference was statistically non-significant (P > 0.05). In the per protocol analysis the infection rates were 5% (5 patients, n = 100) in the group receiving 48 h of prophylactic antibiotic therapy and 8% (8 patients, n = 100) in the group receiving 72 h of prophylactic antibiotic therapy, and the difference was again statistically non-significant (P > 0.05). The results of Fishers exact test revealed that the duration of surgery lasting for >5 h is an independent risk factor for surgical site infection. CONCLUSIONS Forty-eight hours of a prophylactic antibiotic combination using a third-generation cephalosporin and an aminoglycoside is as effective as a 72 h regimen for preventing surgical site infection in patients undergoing CABG and valve surgery.

Thoracic epidural anesthesia in cardiac surgery - Current standing

Annals of Cardiac Anaesthesia  Vol. 12:2  Jul-Dec-2009 pain relief, or improving quality of recovery? This question has recently been addressed by Wijeysundera and colleagues,[6] who performed a propensity scored analysis of mortality in patients receiving postoperative epidural analgesia for noncardiac surgery. They raise a point that a powerful study to detect a small (0.2% absolute reduction) mortality risk reduction in high risk patients would require, a study of 55,000 patients in each group. They found a small reduction in mortality in the patients receiving epidural analgesia (number needed to save one life was 477). The incidence of spinal hematoma was rare (0.02%), and was not significantly different between those receiving epidurals or not. The authors point out that their study should not be used as evidence that epidurals will save lives, as the effect size was small and the numbers required were large. However, the implication is that for every patient damaged with an epidural, perhaps nine lives can be saved. The fear that epidurals are inherently more dangerous than conventional treatments has not been substantiated in this large cohort study. Even in cardiac surgery, the fear that systemic anticoagulation will increase, the risk of hematoma has not been borne out over the last 20 years. In an accompanying editorial by Barrington and Scott,[7] the issue of lives saved to patients damaged lead them to conclude that, “in many cases, pain relief alone is an unambiguous clinical indication for postoperative epidural analgesia”.