Goverdhan Dutt Puri

Comparison of closed loop vs. manual administration of propofol using the Bispectral index in cardiac surgery

Background: In recent years, electroencephalographic indices of anaesthetic depth have facilitated automated anaesthesia delivery systems. Such closed‐loop control of anaesthesia has been described in various surgical settings in ASA I–II patients (1–4), but not in open heart surgery characterized by haemodynamic instability and higher risk of intra‐operative awareness. Therefore, a newly developed closed‐loop anaesthesia delivery system (CLADS) to regulate propofol infusion by the Bispectral index (BIS) was compared with manual control during open heart surgery.

The effect of magnesium sulphate on hemodynamics and its efficacy in attenuating the response to Endotracheal intubation in patients with coronary artery disease

Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects.Magnesium has direct vasodilating properties on coronary arteries and inhibits catecholamine release, thus attenuating the hemodynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary artery bypass grafting to evaluate the hemodynamic effects of magnesium and its efficacy in attenuating the response to endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before intubation. The hemodynamic variables were recorded before induction, after the trial drug, after induction, and after endotracheal intubation. Automatic ST segment analysis was performed throughout the study period. Magnesium sulfate administration was associated with increased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in the magnesium group had significant ST depression compared with three patients in the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal intubation. Thus, magnesium is an useful adjuvant to attenuate endotracheal intubation response in patients with CAD. Implications: Endotracheal intubation produces adverse hemodynamic effects, which may be more detrimental in patients with coronary artery disease than in healthy patients. The present study shows that magnesium administered before endotracheal intubation can attenuate this response better than lidocaine. (Anesth Analg 1998;87:808-11)

Nifedipine attenuates the intraocular pressure response to intubation following succinylcholine

Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied to evaluate the efficacy of sublingual nifedipine in attenuating the intraocular pressure response to succinylcholine administration, laryngoscopy and intubation. The patients were randomly given either nifedipine 10 mg or placebo sublingually 20 minutes before induction of anaesthesia. Intraocular pressure (IOP) and systolic blood pressure (SBP) were recorded before and after induction of anaesthesia. The IOP response to succinylcholine administration, laryngoscopy and intubation was significantly less in patients receiving nifedipine (P > 0.01). The mean maximum rise in IOP above basal level at one minute postintubation was 7.82 mmHg in the control group compared with 0.15 mmHg in the nifedipine pretreated group. These results suggest that sublingual nifedipine is effective in attenuating the IOP response after succinylcholine administration, laryngoscopy and intubation.RésuméNous avons évalué le role de la nifédipine sub-linguale dans la prevention de l’augmentation de la pression intra-oculaire suivant l’injection de succinylcholine et l’intubation chez 40 patients aux yeux normaux. Le hasard déterminait s’ils allaient recevoir 10 mg de nifédipine ou un placebo 20 minutes avant l’induction de leur anesthésie pour chirurgie non-ophtalmique. Nous mesurions les pressions intra-oculaire (PIO) et artirielle systolique (PAS) avant et apres cette induction. L’augmentation maximale moyenne de la PIO une minute après l’intubation a ete de 7.82 mmHg dans le groupe placebo et de 0.15 mmHg dans le groupe nifédipine (P < 0.01). Donc, la nifédipine sublinguale semble capable de limiter l’augmentation de la PIO suivant la séquence succinylcholine-laryngoscopie-intubation trachéale.

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.

Piroxicam gel, compared to EMLA cream is associated with less pain after venous cannulation in volunteers.

PurposeTo evaluate and compare the analgesic efficacy and antiinflammatory effects of topical piroxicam gel vs eutectic mixture of local anesthetic (EMLA) cream applied to the peripheral venous cannulation site in adult volunteers.MethodsPiroxicam gel and EMLA cream were randomly applied on the dorsum of the right and left hand of ten volunteers who acted as their own control. A venous cannula was inserted (no iv infusion) and removed after one hour. Pain scores and signs of inflammation were noted at the cannulation site up to 48 hr.ResultsPain scores with piroxicam gel were higher on cannulation and on advancement of the cannula (P < 0.05). Thereafter, pain scores were significantly higher with EMLA (P < 0.05). Blanching was present at all the peripheral venous sites treated with EMLA cream. Signs of inflammation (erythema, edema) were not more frequent with EMLA than with piroxicam (P > 0.05). Induration was more frequent with EMLA at six hours.ConclusionIn volunteers EMLA cream is associated with less pain on cannulation and cannula advancement compared to piroxicam gel. Topical application of piroxicam gel before peripheral venous cannulation alleviates pain and, possibly, inflammation in the period subsequent to cannulation itself.RésuméObjectifÉvaluer et comparer l’efficacité analgésique et les effets anti-inflammatoires d’un gel de piroxicam topique et d’une crème d’un mélange eutectique d’anesthésique local (EMLA) appliqués autour du site d’une canulation veineuse chez des adultes volontaires.MéthodeLe gel de piroxicam ou la crème EMLA ont été appliqués, aléatoirement, au dos des mains droite et gauche de dix volontaires qui étaient leur propre témoin. Une canule veineuse a été insérée (sans perfusion iv) et enlevée une heure plus tard. Les scores de douleur et les signes d’inflammation ont été notés au site de canulation pendant une période allant jusqu’à 48 h.RésultatsLes scores de douleur ont été plus élevés avec le gel de piroxicam pendant la canulation et la poussée de la canule ((P < 0,05). Par la suite, les scores de douleur ont été significativement plus élevés avec le EMLA (P < 0,05). La blancheur était présente à tous les sites veineux périphériques traités avec la crème EMLA. Les signes d’inflammation (érythème, œdème) étaient comparables avec les deux médicaments (P > 0,05). L’induration a été plus fréquente avec le EMLA à six heures.ConclusionChez des volontaires, la crème EMLA est associée à moins de douleur, que le gel de piroxicam, au site de canulation et pendant la poussée de la canule. L’application topique de gel de piroxicam avant la canulation veineuse atténue la douleur et, possiblement, l’inflammation après la canulation elle-même.

Bispectral index-controlled postoperative sedation in cardiac surgery patients: a comparative trial between closed loop and manual administration of propofol.

Background and objective Postoperative cardiac surgery patients are usually sedated according to clinical sedation scores. Electrophysiological data derived from electroencephalography, such as the bispectral index (BIS), have been reported to assess and quantify the level of sedation, although experience in these patients is limited. In the current study, we evaluated a closed-loop system – closed-loop anaesthesia delivery system (CLADS) – for postoperative sedation after open heart surgery using BIS. Methods Forty-one postoperative cardiac surgery patients in the age group 18–65 years were included. In the postanaesthesia care unit, they were randomly allocated to two groups: a CLADS group, which received a continuous infusion of propofol using CLADS, and a manual group, which received propofol at a rate manually adjusted by the clinician. Propofol was administered in both groups to maintain the BIS at a target of 70 for adequate sedation. Patients were weaned from mechanical ventilation and the trachea extubated after confirmation of haemodynamic stability, haemostasis, normothermia and mental orientation. Results The percentage of total sedation time during which BIS remained within ±10 of the target value (BIS of 70 during sedation) was significantly higher in the CLADS group than in the manual group (P = 0.002). The assessment of performance parameters using median performance error and median absolute performance error indicated better performance in the CLADS group. Manual control required the propofol infusion rate to be changed frequently, taking up considerable time and attention of the clinician. Conclusion Closed-loop delivery of propofol to control BIS for postoperative sedation is feasible and efficient after cardiac surgery.

Evaluation of closed-loop anesthesia delivery for propofol anesthesia in pediatric cardiac surgery.

The objective of this study was to compare the feasibility of closed‐loop anesthesia delivery with manual control of propofol in pediatric patients during cardiac surgery.

Glucose-6-phosphate dehydrogenase deficiency and cardiac surgery

Cardiac surgery involving cardiopulmonary bypass (CPB) in its conventional form involves many processes leading to free radical production, such as perioperative ischemia, reperfusion, circulation of whole body blood through the CPB circuit, hypothermia and acidosis. The red blood cells of a glucose-6-phosphate dehydrogenase (G6PD)-deficient person are unable to scavenge these free radicals, resulting in haemolysis. Here, we describe the successful anaesthetic management of two G6PD-deficient children who underwent cardiac surgery, on and off CPB, without any obvious haemolytic reaction, followed by a discussion of the disorder, with specific consideration of perioperative management of such cases.

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.

Closed-loop isoflurane administration with bispectral index in open heart surgery: Randomized controlled trial with manual control

OBJECTIVE Improved anesthetic agent delivery system (IAADS), a modification of closed-loop anesthesia delivery system (CLADS), is designed to deliver inhalational anesthetics and propofol through closed-loop control with bispectral index (BIS) as target. We compared the performance of IAADS with the manual control isoflurane administration during cardiac surgery. METHODS Forty patients of ASA (American Society of Anesthesiologists) physical status class II-III, undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) in a tertiary care hospital in India were randomized to receive isoflurane through a closed-loop system (IAADS group) or through a Tech 7 vaporizer adjusted manually (manual group) to achieve a target BIS of 50. Patients were induced with a propofol infusion and isoflurane was started after intubation. During CPB, patients received propofol; isoflurane was restarted after separation from CPB. The efficacy of IAADS in controlling depth of anesthesia and hemodynamic variations was compared with that of manual control. RESULTS IAADS was able to maintain BIS within ± 10 of target for significantly longer period (84.6 ± 7.2% in IAADS group vs. 75.9 ± 11.2 in manual group, p < 0.01). Both overall performance, as assessed by global score (p < 0.01), and precision, as judged by median absolute performance error (MDAPE) (p < 0.04), were significantly better in the IAADS group. The IAADS group required significantly less propofol for induction (1.3 ± 0.4 mg/kg in IAADS vs. 1.6 ± 0.5 mg/kg in manual, p < 0.05) and less isoflurane during maintenance of anesthesia (3.3 ± 0.8 ml/h vs. 3.4 ± 0.9 ml/h, p < 0.01). CONCLUSION The present study proves the feasibility and efficacy of inhalation anesthetic administration through closed-loop control. This is the first system that has been developed to control intravenous and inhalational anesthetic agents in a closed-loop model using BIS.