Ps Nagaraja

Transesophageal echocardiography estimation of coronary sinus blood flow for the adequacy of revascularization in patients undergoing off-pump coronary artery bypass graft

Aims and Objectives: Physiologically coronary sinus (CS) drains the left coronary artery (LCA) territory. Stenosis of the branches of LCA may decrease the coronary sinus blood flow (CSBF). Any intervention that aims at restoring the flow of the stenosed vessel increases coronary artery flow that should consequently increase the CSBF. Hence, this study was undertaken to assess the CSBF before and after each branch of LCA to determine the adequacy of surgical revascularization in patients undergoing elective off pump coronary artery bypass grafting (OPCAB) using transesophageal echocardiography (TEE). Materials and Methods: Thirty consecutive patients scheduled for elective OPCAB were enrolled. CSBF was assessed before and after each branch of LCA revascularization using TEE. Left internal mammary artery (LIMA) Doppler was also obtained post LIMA to left anterior descending (LAD) grafting. Results: Hemodynamic and echocardiographic variables were compared by means of Students t-test for paired data before and after revascularization. The CSBF per beat (1.28 ± 0.71), CSBF per minute (92.59 ± 59.32) and total velocity time integral (VTI) (8.93 ± 4.29) before LAD grafting showed statistically significant increase to CSBF per beat (1.70 ± 0.89), CSBF per minute (130.72 ± 74.22) and total VTI (11.96 ± 5.68) after LAD revascularization. The CSBF per beat (1.67 ± 1.03), CSBF per minute (131.91 ± 86.59) and total VTI (11.00 ± 5.53) before obtuse marginal (OM) grafting showed statistically significant increase to CSBF per beat (1.91 ± 1.03), CSBF per min (155.20 ± 88.70) and total VTI (12.09 ± 5.43) after OM revascularization. In 9 patients, color flow Doppler of LIMA could be demonstrated which showed diastolic predominant blood flow after LIMA to LAD grafting. Conclusion: Demonstration of CSBF was simple and monitoring the trend of CSBF values before and after each graft of LCA territory will guide to determine the adequacy of surgical revascularization.

To evaluate dexmedetomidine as an additive to propofol for sedation for elective cardioversion in a cardiac intensive care unit: A double-blind randomized controlled trial

Introduction: Propofol may lead to patient recall and discomfort when used for sedation in elective cardioversion. The aim of the present study was to evaluate dexmedetomidine as an additive to propofol for sedation in elective cardioversion. Materials and Methods: A total of 500 patients undergoing elective cardioversion were randomized into Group 1 (n = 250) and Group 2 (n = 250) on the basis of computer-generated randomization table. Patients in Group 1 were given dexmedetomidine (1 mcg/kg) over 10 min before giving propofol (1 mg/kg), while patients in Group 2 were given only propofol (1 mg/kg). One or two additional doses of 0.5 mg/kg propofol were given if modified Ramsay Sedation Score (mRSS) was <5. Number of patients requiring additional doses were noted. Any hemodynamic or respiratory complication along with the mean time to recovery (mRSS = 1) was recorded. Patient recall, patient discomfort, and further requirement of cardioversion in the next 24 h were also noted. Results: About 10% patients in Group 1 and 64% patients in Group 2 required the first additional dose of propofol. While no patient in Group 1 required second dose, 16% patients in Group 2 required second dose of propofol. The mean time to recovery in Group 1 was 8.36 ± 3.08 min and 8.22 ± 2.38 min in Group 2 (P = 0.569). Sixty-seven patients (26.8%) in Group 1 and 129 patients (51.6%) in Group 2 reported remembering something (P < 0.0001), i.e., recall. Thirty-five patients (14%) in Group 1 and 79 patients (31.6%) in Group 2 reported dreaming during the procedure (P < 0.0001). Visual analog scale score was higher in Group 1 as compared to Group 2. Six patients in Group 1 and 24 patients in Group 2 had a requirement of repeat cardioversion in 24-h follow-up (P = 0.001). Conclusions: Dexmedetomidine is a useful adjunct to propofol for elective cardioversion.

Effect of dexmedetomidine on diseased coronary vessel diameter and myocardial protection in percutaneous coronary interventional patients.

Introduction: Dexmedetomidine is an alpha-2 agonist used for conscious sedation. It has also been shown to have a myocardial protective effect in off-pump coronary artery bypass patients. The aim of the study was to assess the effect of dexmedetomidine for myocardial protection in percutaneous coronary interventional patients. Methodology: A total of 60 patients (group dexmedetomidine, n = 30 and group normal saline, n = 30) were enrolled in the study. Dexmedetomidine infusion (1 mcg/kg) over 15 min was given as a loading dose after coronary angiography in group dexmedetomidine (D) while normal saline was given in the control group (C) and later maintenance infusion was started at 0.5 mcg/kg/h in both the groups. Coronary vessel diameter was noted before (T0) and after (T1) loading dose of dexmedetomidine/saline in each group. Troponin T (Trop T) values were noted at baseline (T0), 6 h (T2), 12 h (T3) and 24 h (T4) after starting the loading dose. Hemodynamic variables (heart rate [HR] and blood pressure) were monitored at T0, T1, and at regular intervals till 2 h postprocedure. Results: Coronary vessel diameter and HR significantly decreased in group D as compared to control group (P < 0.05) whereas the decrease in Trop T at 6 h, 12 h, and 24 h were not statistically significant between the two groups. Conclusion: Dexmedetomidine decreases the coronary vessel diameter, but maintains the myocardial oxygen demand-supply ratio by decreasing the HR. The decrease in Trop T is statistically insignificant at the doses used.

Comparison between noninvasive measurement of central venous pressure using near infrared spectroscopy with an invasive central venous pressure monitoring in cardiac surgical Intensive Care Unit.

Introduction: Central venous pressure (CVP) measurement is essential in the management of certain clinical situations, including cardiac failure, volume overload and sepsis. CVP measurement requires catheterization of the central vein which is invasive and may lead to complications. The aim of this study was to evaluate the accuracy of measurement of CVP using a new noninvasive method based on near infrared spectroscopy (NIRS) in a group of cardiac surgical Intensive Care Unit (ICU) patients. Methodology: Thirty patients in cardiac surgical ICU were enrolled in the study who had an in situ central venous catheter (CVC). Sixty measurements were recorded in 1 h for each patient. A total of 1800 values were compared between noninvasive CVP (CVPn) obtained from Mespere VENUS 2000 CVP system and invasive CVP (CVPi) obtained from CVC. Results: Strong positive correlation was found between CVPi and CVPn (R = 0.9272, P < 0.0001). Linear regression equation - CVPi = 0.5404 + 0.8875 × CVPn (r2 = 0.86, P < 0.001), Bland-Altman bias plots showed mean difference ± standard deviation and limits of agreement: −0.31 ± 1.36 and − 2.99 to + 2.37 (CVPi-CVPn). Conclusion: Noninvasive assessment of the CVP based on NIRS yields readings consistently close to those measured invasively. CVPn may be a clinically useful substitute for CVPi measurements with an advantage of being simple and continuous. It is a promising tool for early management of acute state wherein knowledge of CVP is helpful.

Evaluation of adjusted central venous blood gases versus arterial blood gases of patients in post-operative paediatric cardiac surgical intensive care unit

Background and Aims: Central venous catheters are in situ in most of the intensive care unit (ICU) patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation. The aim of this study was to examine the reliability between adjusted central venous blood gas (aVBG) and arterial blood gas (ABG) samples for pH, partial pressure of carbon-di-oxide (pCO2), bicarbonate (HCO3−), base excess (BE) and lactates in paediatric cardiac surgical ICU. Methods: We applied blood gas adjustment rule, that is aVBG pH = venous blood gas (VBG) pH +0.05, aVBG CO2 = VBG pCO2 - 5 mm Hg from the prior studies. In this study, we validated this relationship with simultaneous arterial and central venous blood obtained from 30 patients with four blood sample pairs each in paediatric cardiac surgical ICU patients. Results: There was a strong correlation (R i.e., Pearsons correlation) between ABG and aVBG for pH = 0.9544, pCO2 = 0.8738, lactate = 0.9741, HCO3− = 0.9650 and BE = 0.9778. Intraclass correlation co-efficients (ICCs) for agreement improved after applying the adjustment rule to venous pH (0.7505 to 0.9454) and pCO2 (0.4354 to 0.741). Bland Altman showed bias (and limits of agreement) for pH: 0.008 (−0.04 to + 0.057), pCO2: −3.52 (–9.68 to +2.65), lactate: −0.10 (−0.51 to +0.30), HCO3−: −2.3 (–5.11 to +0.50) and BE: −0.80 (−3.09 to +1.49). Conclusion: ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC) after adjusting the VBG. Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

Anesthetic management of a case of Gilbert's syndrome for mitral and aortic valve replacement: Role of transesophageal echocardiography

Gilberts syndrome (GS) is an autosomal inherited disorder characterized by relative deficiency of glucuronyl transferase and poor uptake of unconjugated bilirubin by hepatocytes. Cardiac surgery on cardiopulmonary bypass (CPB) in these patients triggers further hepatic dysfunction. Transesophageal echocardiography (TEE) and Doppler assessment of hepatic vein help in assessing hepatic blood flow (HBF) during cardiac surgery. Here, we discuss anesthetic management and role of TEE in maintaining HBF perioperatively in a 25-year-old male patient with GS undergoing double valve replacement with tricuspid valve plasty. TEE-guided HBF monitoring and management of hepatic perfusion by modifying anesthetic and CPB protocol resulted in the favorable outcome.

Transesophageal Echocardiographic Assessment of Pulmonary Artery-to-Ascending Aorta Ratio for the Detection of Pulmonary Hypertension in Cardiac Surgical Patients

OBJECTIVE The objective of the study was to investigate if the main pulmonary artery (mPA)-to-ascending aorta (AscAo), (mPA:AscAo) ratio could serve as a screening tool in identifying pulmonary artery hypertension (PAH). DESIGN A prospective observational study. SETTING Tertiary care center, university hospital. PARTICIPANTS Fifty-four adult patients undergoing off-pump coronary artery bypass grafting surgery (OPCAB). INTERVENTIONS mPA and AscAo transverse diameters were measured by transesophageal echocardiography (TEE) and the mean pulmonary arterial pressures (mPAP) were recorded simultaneously using a pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS mPA:AscAo ratio demonstrated significant linear correlation with mPAP measured by pulmonary artery catheterization (ie, r = 0.61, confidence interval [CI] = 0.5352-0.6736, p < 0.0001). Receiver operating characteristic curves were performed to evaluate sensitivity and specificity of mPA:AscAo ratio ≥1 for diagnosing PAH (mPAP ≥25 mmHg). Area under the curve for mPA:AscAo ratio was 0.91 (95% CI, 0.869-0.936, p < 0.0001), with a sensitivity of 84.27%, specificity of 83.92%, positive-predictive value of 87.6% and negative-predictive value of 81.1% for a mPAP ≥25 mmHg. CONCLUSIONS The ratio of mPA:AscAo is a simple, reliable, and reproducible method that can be obtained through TEE, which guides the clinician to screen patients with PAH.

Effect of periradial administration of papaverine on radial artery diameter

Background: Radial artery cannulation is a skillful procedure. An experienced anesthesiologist might also face difficulty in cannulating a feeble radial pulse. Aim: The purpose of the study was to determine whether periradial subcutaneous administration of papaverine results in effective vasodilation and improvement in the palpability score of radial artery. Settings and Design: Prospective, double-blinded trial. Methodology: Thirty patients undergoing elective cardiac surgery were enrolled in the study. 30 mg of papaverine with 1 ml of 2% lignocaine and 3 ml of normal saline were injected subcutaneously 1–2 cm proximal to styloid process of the radius. Radial artery diameter before and after 20 min of injection papaverine was measured using ultrasonography. The palpability of the radial pulse was also determined before the injection of papaverine and 20 min later. Patients were monitored for hemodynamics and any complications were noted. Statistical Analysis Used: Students t-test for paired data. Results: Radial artery diameter increased significantly (P < 0.0001), and the pulse palpability score also showed statistically significant improvement (P < 0.0001) after periradial subcutaneous administration of papaverine. There was no statistically significant difference in heart rate, mean arterial blood pressure before and after papaverine injection. No complications were noted in 24 h of follow-up. Conclusion: Periradial subcutaneous administration of papaverine significantly increased the radial artery diameter and pulse palpability score, which had an impact on ease of radial artery cannulation essential for hemodynamic monitoring in cardiac surgical patients.

Cardiac surgery in renal transplanted patient : A case report

Cardiac surgery causes high mortality among post-renal-transplant patients. These patients are on steroids, which can accelerate atherosclerosis, and on immunosuppressive drugs, which expose the patient to infection. Here we report a case of a post-renal-transplant patient who underwent off-pump coronary artery bypass graft surgery with favorable outcome. In the present case, perioperative renal dysfunction was prevented by maintaining strict asepsis and adequate renal perfusion, by titrating the fluid based on pulmonary artery pressures, by maintaining urine output greater than 1 ml/kg/h, by avoiding cardiopulmonary bypass, and by titrating drugs according to the bispectral index, which resulted in early extubation and better outcome of the patient.

Emergency mitral valve replacement and cesarean section in parturients: Two case reports

Cardiac surgery during pregnancy using cardiopulmonary bypass has a maternal mortality rate (MMR) of about 3-15%. Cardiopulmonary bypass, in addition, alters placental perfusion, which can increase infant mortality. Here, we report two cases of parturients with severe mitral stenosis, who developed acute mitral regurgitation (MR) after percutaneous transluminal mitral commissurotomy (PTMC) due to anterior mitral leaflet tear. They were posted for emergency mitral valve replacement (MVR) followed by cesarean section. Altering the routine cardiopulmonary bypass and anesthesia protocol resulted in a favorable maternal and fetal outcome.