Aveek Jayant

A Multicenter Evaluation of a Closed-Loop Anesthesia Delivery System: A Randomized Controlled Trial

BACKGROUND:Closed-loop systems for anesthesia delivery have been shown to outperform traditional manual control in different clinical settings. The present trial was aimed at evaluating the feasibility and efficacy of Bispectral Index (BISTM)-guided closed-loop anesthesia delivery system (CLADS) in comparison with manual control across multiple centers in India. METHODS:Adult patients scheduled for major surgical procedures of an expected duration of 1 to 3 hours were randomized across 6 sites into 2 groups: a CLADS group and a manual group. In the manual control group, propofol infusion was titrated manually by the attending anesthesiologist to a BIS of 50 during induction and maintenance. Analgesia was maintained with fentanyl infusion and nitrous oxide in both groups. In the CLADS group, both induction and maintenance of anesthesia were performed automatically using CLADS. The primary outcome measure was the performance of the system as assessed by the percentage of total anesthesia time BIS remained ±10 of target BIS. The secondary outcome measures were a percentage of anesthesia-time heart rate and mean arterial pressure within 25% of the baseline, median absolute performance error, wobble, and global score. Wobble indicates intraindividual variability in the control of BIS, and global score reflects the overall performance; lower values indicate superior performance for both parameters. The performance parameters of the system also were compared among the participating sites. RESULTS:Two hundred forty-two patients were randomized. BIS was maintained within ±10 of target for significantly longer time in the CLADS group (81.4% ± 8.9 % of anesthesia duration) than in the manual group (55.34% ± 25%, P < 0.0001). The indices that assess performance were significantly better in the CLADS group than the manual group as follows: median absolute performance error was 10 (10, 12) (median [interquartile range]) in the CLADS group versus 18 (14, 24) in the manual group, P < 0.0001; wobble was 9 (8, 10) in CLADS group versus 10 (8, 14) in the manual group, P = 0.0009; and Global score, which reflects overall performance, was 24 (19, 30) in the CLADS group versus 51 (31, 99) in the manual group, P < 0.0001. The percentage of time heart rate was within 25% of the baseline was significantly greater in the CLADS group (heart rate of 95 [87, 99], median [interquartile range], in the CLADS group versus 90 [75, 98] in the manual group P = 0.0031). On comparison of data between the centers, the performance parameters did not differ significantly among the centers in the CLADS group (P = 0.94), but the parameters differed significantly among the centers in the manual group (P < 0.001). CONCLUSIONS:Our study in a multicenter setting proves the consistently better performance of automated anesthesia drug delivery compared with conventional manual control. This highlights an important advantage of an automated system for delivering standardized anesthesia, thereby overcoming differences in practices among anesthesiologists.

Propofol–fentanyl anaesthesia at high altitude: anaesthetic requirements and haemodynamic variations when compared with anaesthesia at low altitude

Background: There are few published accounts of anaesthesia delivery at high altitude. Natives at high altitude are known to have altered cardiorespiratory reserve. This study seeks to demonstrate the safety of propofol–fentanyl anaesthesia at high altitude titrated to the bispectral index (BIS) (3505 metres above sea level) in native highlanders. It also shows the differential effects of anaesthesia and surgery on the haemodynamics of such individuals as compared with individuals living at low altitude.

Effect of continuous paravertebral dexmedetomidine administration on intraoperative anesthetic drug requirement and post thoracotomy pain syndrome after thoracotomy: A randomized controlled trial

OBJECTIVES To assess the effect of paravertebral administration of dexmedetomidine as an adjuvant to local anesthetic on the intraoperative anesthetic drug requirement and incidence of post-thoracotomy pain syndrome. DESIGN Prospective, randomized, controlled, double-blind trial. SETTING Single university hospital. PARTICIPANTS The study comprised 30 patients who underwent elective thoracotomy and were assigned randomly to either the Ropin or Dexem group (n = 15 each). INTERVENTIONS All patients received the study medications through paravertebral catheter. Patients in the Ropin group received a bolus of 15 mL of 0.75% ropivacaine over 3-to-5 minutes followed by an infusion of 0.2% ropivacaine at 0.1 mL/kg/hour. Patients in the Dexem group received 15 mL of 0.75% ropivacaine plus dexmedetomidine, 1 µg/kg bolus over 3-to-5 minutes followed by an infusion of 0.2% ropivacaine plus 0.2 µg/kg/hour of dexmedetomidine at 0.1 mL/kg/hour. MEASUREMENTS AND MAIN RESULTS The primary outcome of the study was intraoperative anesthetic drug requirement. The secondary outcome was the incidence of post-thoracotomy pain syndrome 2 months after surgery. The amount of propofol required for induction of anesthesia was significantly less in the Dexem group (Dexem 49.33±20.51 v 74.33±18.40 in the Ropin group, p = 0.002). End-tidal isoflurane needed to maintain target entropy was significantly less in the Dexem group at all time points. Intraoperative fentanyl requirement was lower in the Dexem group (Dexem 115.33±33.77 v 178.67±32.48 in the Ropin group, p = 0.002). Postoperative pain scores and morphine consumption were significantly less in the Dexem group (p<0.001). The incidence of post-thoracotomy pain syndrome was comparable between the 2 groups (69.23% v 50%, p = 0.496). CONCLUSIONS Paravertebral dexmedetomidine administration resulted in decreased intraoperative anesthetic drug requirement, less pain, and lower requirements of supplemental opioid in the postoperative period. However, it had no effect on the incidence of post-thoracotomy pain syndrome.

Delirium after cardiac surgery: A pilot study from a single tertiary referral center

Background: Advances in cardiac surgery has shifted paradigm of management to perioperative psychological illnesses. Delirium is a state of altered consciousness with easy distraction of thoughts. The pathophysiology of this complication is not clear, but identification of risk factors is important for positive postoperative outcomes. The goal of the present study was to prospectively identify the incidence, motoric subtypes, and risk factors associated with development of delirium in cardiac surgical patients admitted to postoperative cardiac intensive care, using a validated delirium monitoring instrument. Materials and Methods: This is a prospective, observational study. This study included 120 patients of age 18-80 years, admitted to undergo cardiac surgery after applying inclusion and exclusion criteria. Specific preoperative, intraoperative, and postoperative data for possible risk factors were obtained. Once in a day, assessment of delirium was done. Continuous variables were measured as mean ± standard deviation, whereas categorical variables were described as proportions. Differences between groups were analyzed using Student′s t-test, Mann-Whitney U-test, or Chi-square test. Variables with a P < 0.1 were then used to develop a predictive model using stepwise logistic regression with bootstrapping. Results: Delirium was seen in 17.5% patients. The majority of cases were of hypoactive delirium type (85.72%). Multiple risk factors were found to be associated with delirium, and when logistic regression with bootstrapping applied to these risk factors, five independent variables were detected. History of hypertension (relative risk [RR] =6.7857, P = 0.0003), carotid artery disease (RR = 4.5000, P < 0.0001) in the form of stroke or hemorrhage, noninvasive ventilation (NIV) use (RR = 5.0446, P < 0.0001), Intensive Care Unit (ICU) stay more than 10 days (RR = 3.1630, P = 0.0021), and poor postoperative pain control (RR = 2.4958, P = 0.0063) was associated with postcardiac surgical delirium. Conclusions: Patients who developed delirium had systemic disease in the form of hypertension and cerebrovascular disease. Delirium was seen in patients who had higher postoperative pain scores, longer ICU stay, and NIV use. This study can be used to develop a predictive tool for diagnosing postcardiac surgical delirium.

Perioperative Follow-Up of Patients With Severe Pulmonary Artery Hypertension Secondary to Left Heart Disease: A Single Center, Prospective, Observational Study.

OBJECTIVE A substantial portion of the Indian cardiac surgery population experiences rheumatic valve disease that progresses to severe pulmonary artery hypertension (PAH) in a few patients. Right ventricular (RV) function, particularly in the perioperative period, has been studied sparsely. The authors describe serial RV function and clinical variables in the perioperative period in patients with severe PAH secondary to left heart disease. DESIGN Prospective, observational study. SETTING University hospital. PARTICIPANTS Patients with PAH. INTERVENTIONS The study comprised consecutive patients referred for open cardiac surgery from January 2012 to June 2013 who also had an estimated right ventricular systolic pressure≥50 mmHg on referral echocardiogram. Composite echocardiographic assessment of right ventricular size and linear/two-dimensional tissue Doppler systolic function and diastolic function analysis were performed at predetermined intervals. Data from right heart catheterization, inotrope use, fluid requirements, mechanical ventilation logs, and intensive care stay also were acquired. MEASUREMENTS AND MAIN RESULTS A complete dataset was obtained in 20 of 22 patients enrolled in the study. Serial comparison of most RV echocardiographic function variables were noted to be abnormal at baseline, deteriorating further in the immediate postoperative period and trending to a partial recovery at discharge from the intensive care unit, particularly for longitudinal assessment of the RV. Fractional area change, although abnormal, was noted to be preserved. Pulmonary artery systolic pressures registered significantly declined after intervention. The clinical course was largely uneventful. CONCLUSION Although linear echocardiographic RV function was grossly abnormal in the perioperative period in this patient subset with PAH, there was apparent disjunction with the clinical course.

Closed loop anaesthesia at high altitude (3505 m above sea level): Performance characteristics of an indigenously developed closed loop anaesthesia delivery system

Background: Closed loop anaesthesia delivery systems (CLADSs) are a recent advancement in accurate titration of anaesthetic drugs. They have been shown to be superior in maintaining adequate depth of anaesthesia with few fluctuations as compared with target-controlled infusion or manual titration of drug delivery. Methods: Twenty patients scheduled to undergo general abdominal or orthopaedic procedures under general anaesthesia at Leh (3505 m above sea level) were recruited as subjects. Anaesthesia was delivered by a patented closed loop system that uses the Bispectral Index (BIS™) as a feedback parameter to titrate the rate of propofol infusion. All vital parameters, drug infusion rate and the BIS™ values were continuously recorded and stored online by the system. The data generated was analysed for the adequacy of anaesthetic depth, haemodynamic stability and post-operative recovery parameters. Results: The CLADS was able to maintain a BIS™ within ±10 of the target of 50 for 85.0±7.8% of the time. Haemodynamics were appropriately maintained (heart rate and mean arterial blood pressure were within 25% of baseline values for 91.2±2.2% and 94.1±3% of the total anaesthesia time, respectively). Subjects were awake within a median of 3 min from cessation of drug infusion and achieved fitness to recovery room discharge within a median of 15 min. There were no adverse events or report of awareness under anaesthesia. Conclusions: The study demonstrates the safety of our CLADS at high altitude. It seeks to extend the use of our system in challenging anaesthesia environments. The system performance was also adequate and no adverse events were recorded.

Perioperative echocardiography-derived right ventricle function parameters and early outcomes after tetralogy of Fallot repair in mid-childhood: a single-center, prospective observational study.

Right ventricular (RV) function alterations are invariably present in all patients after tetralogy of Fallot (TOF) repair. Unlike the developed world where most of the patients with TOF are corrected in infancy, average age of presentation and thus surgery for these patients in the developing world may be higher. We aimed to study the correlation between RV function parameters such as tricuspid annular peak systolic excursion (TAPSE), fractional area change (FAC), and tricuspid annular peak systolic velocity (S’) with early outcome variables after intracardiac repair for TOF.

Left atrial myxoma, ruptured chordae tendinae causing mitral regurgitation and coronary artery disease.

Mitral regurgitation is uncommon with left atrial myxoma. The echocardiographic assessment of presence of mitral regurgitation and its severity are impaired by the presence of left atrial myxoma. We describe an uncommon association of left atrial myxoma with coronary artery disease and mitral regurgitation. MR was reported as mild on pre-operative transthoracic echocardiography but found to be severe due to ruptured chordae tendinae during intra-operative transesophageal echocardiography, which lead to change in the surgical plan to mitral valve replacement in addition to excision of myxoma.

Tricuspid valve straddling: An uncommon cause of left ventricular outflow tract obstruction in transposition of great artery with ventricular septal defect

Transposition of great arteries (TGA) can be associated with left ventricle outflow tract (LVOT) obstruction. In the presence of ventricular septal defect (VSD), septal leaflet of tricuspid valve may prolapse through perimembranous VSD or rarely tricuspid valve tissue may override to produce LVOT obstruction. Occasionally, this may be mistaken for vegetation due to associated pulmonary valve endocarditis. We report a case of d-TGA with presumptive pulmonary valve endocarditis and LVOT obstruction that was found to be due to tricuspid valve straddling on transesophageal echocardiography, resulting in change in the surgical plan and thus avoiding catastrophe.

The utility of targeted perioperative transthoracic echocardiography in managing an adult patient with anomalous origin of the left coronary artery-pulmonary artery for noncardiac surgery

Congenital coronary artery anomalies as a whole are uncommon. Abnormal origin of the left coronary artery from the pulmonary artery (ALCAPA) is probably the most common congenital coronary defect. An overwhelming majority of the patients with untreated ALCAPA do not survive to adulthood. As yet, there is no consensus on the management of adults with ALCAPA. We describe a patient with breast malignancy and incidentally detected ALCAPA; primacy was given to treatment of the oncologic condition as a first step. Anesthesia management was focused on maintaining adequate collateral coronary perfusion and avoidance of excessive loading of the left ventricle. This was achieved using a simplified transthoracic echocardiography (TTE) protocol at the time of induction of anesthesia; TTE was also used to reconfirm the absence of disturbances in myocardial function at the end of surgery. We sugggest the routine use of tte in managing perioperative care in low resource settings when the underlying cardiac disease is rare and the evidence base if often insufficient.