Assessment of the effect of two different doses of intranasal nitroglycerine spray on attenuation of haemodynamic stress response to pneumoperitoneum in laparoscopic surgeries: A randomised, double-blinded study

Background and Aims:

The stress response to pneumoperitoneum can be deleterious due to its effects on haemodynamics, thereby increasing the morbidity. We intended to compare different doses of nitroglycerine nasal spray to obtund these responses and to look for any side effects.

Methods:

After ethical committee clearance and clinical trials registration, 70 patients scheduled for laparoscopic cholecystectomy were recruited. Random allocation was done into two groups by a computer generated randomisation table. Group N4 (n = 35) received 400 μg nitroglycerine and group N8 (n = 35) received 800 μg nitroglycerine with an intranasal spray 2 min prior to pneumoperitoneum. All the haemodynamic parameters were monitored at regular intervals.

Results:

The heart rate was comparable between the groups except at 6 and 10 min of pneumoperitoneum but showed significant increase from baseline within the groups. Mean arterial pressure (MAP) was statistically significant between the groups, being higher in group N4. Within group N4, MAP was significantly low only at 2 min, 4 min of pneumoperitoneum (101.69 ± 12.34 at baseline versus 93.31 ± 8.07 at 2 min and 97.54 ± 9.07 mm Hg at 4 min) and increased significantly at 30 min of pneumoperitoneum (101.69 ± 12.34 at baseline versus 105.66 ± 12.35 mm Hg) and hence, MAP was observed to be around baseline throughout the rest of intraoperative period. Within group N8, there was a significant decrease in mean, systolic and diastolic blood pressure from baseline at most of the time intervals.

Conclusion:

800 μg of intranasal nitroglycerine effectively obtunds the hypertensive response associated with pneumoperitoneum as compared to 400 μg without significant side effects.

Comparison of effects of volume-controlled and pressure-controlled mode of ventilation on endotracheal cuff pressure and respiratory mechanics in laparoscopic cholecystectomies: A randomised controlled trial

Background and Aims:

One of the pathophysiological consequences of pneumoperitoneum is variations in endotracheal cuff pressure (ETTc). Volume-controlled mode and pressure-controlled mode of ventilation being two modes of ventilatory strategies; we intended to find out variations in ETTc governed by respiratory mechanics between these two modes during laparoscopic cholecystectomies.

Methods:

After obtaining ethics committee approval, this randomised (1:1), active-controlled, parallel-assigned study was done on 60 patients undergoing laparoscopic cholecystectomies. These patients were allocated into two groups by computer-generated randomisation: Volume-controlled mode (V) and pressure-controlled mode (P). We observed for variations in ETTc which was the primary aim and haemodynamic parameters; respiratory mechanics at baseline (T1), at pneumoperitoneum (T2), after 10 min (T3), 20 min (T4) of pneumoperitoneum and at desufflation (T5). Post-operative laryngotracheal co-morbidities were also observed. Analysis was done using Statistical Package for the Social Sciences version 16.0 (IBM SPSS Statistics, Somers NY, USA).

Results:

No statistically significant difference was found in both groups either concerning ETTc, haemodynamic parameters or complications. In both groups, ETTc variation was statistically significant when compared from baseline to desufflation (T1 versus T5) and in group V additionally from baseline to time of pneumoperitoneum (T1 versus T2). Group P showed lower peak airway pressure at desufflation and higher mean airway pressure throughout at all the time intervals.

Conclusions:

There is no variation in ETTc between the two modes. Group P appears to be better in terms of lower Ppeak and better Pmean.

Development and validation of a questionnaire for a survey on perioperative fasting practices in India

BACKGROUND AND AIMS

Perioperative fasting guidelines have been published and updated to standardise practices. Hence, Indian Society of Anaesthesiologists decided to conduct a survey to assess the fasting practices and the food habits across India, which would be subsequently used for developing preoperative fasting guidelines for the Indian population. We detail and discuss herewith the content validity of the questionnaire developed for the survey.

METHODS

Thirty-six questions related to perioperative fasting practices were framed based on the collected evidence and relevance to regional diet and concerns. Subsequently, an information sheet was prepared and sent to 10 experts to grade each question. The responses were tabulated, and item-wise content validity index (I-CVI), scale-wise content validity index (S-CVI) and modified kappa statistic were calculated in Microsoft Excel^™ sheet.

RESULTS

Seven of the 10 experts completed the assessment and grading as per the instructions provided and submitted a completed proforma. S-CVI for relevance, simplicity, clarity and ambiguity was 0.72, 0.86, 0.72 and 0.72, respectively. S-CVI/average or average congruency percentagewas 0.95, 0.97, 0.95 and 0.95 for relevance, simplicity, clarity and ambiguity, respectively. Question 2 received an I-CVI of 0.71 in terms of clarity and question 23 received an I-CVI of 0.71. They were modified as persuggestions of the experts.

CONCLUSION

We conclude that our questionnaire designed to ascertain the preoperative fasting practices for a surveymet the content validity criteria both by qualitative and quantitative analyses.

Development and validation of a questionnaire for a survey on perioperative fasting practices in India

Background and Aims:

Perioperative fasting guidelines have been published and updated to standardise practices. Hence, Indian Society of Anaesthesiologists decided to conduct a survey to assess the fasting practices and the food habits across India, which would be subsequently used for developing preoperative fasting guidelines for the Indian population. We detail and discuss herewith the content validity of the questionnaire developed for the survey.

Methods:

Thirty-six questions related to perioperative fasting practices were framed based on the collected evidence and relevance to regional diet and concerns. Subsequently, an information sheet was prepared and sent to 10 experts to grade each question. The responses were tabulated, and item-wise content validity index (I-CVI), scale-wise content validity index (S-CVI) and modified kappa statistic were calculated in Microsoft Excel^™ sheet.

Results:

Seven of the 10 experts completed the assessment and grading as per the instructions provided and submitted a completed proforma. S-CVI for relevance, simplicity, clarity and ambiguity was 0.72, 0.86, 0.72 and 0.72, respectively. S-CVI/average or average congruency percentagewas 0.95, 0.97, 0.95 and 0.95 for relevance, simplicity, clarity and ambiguity, respectively. Question 2 received an I-CVI of 0.71 in terms of clarity and question 23 received an I-CVI of 0.71. They were modified as persuggestions of the experts.

Conclusion:

We conclude that our questionnaire designed to ascertain the preoperative fasting practices for a surveymet the content validity criteria both by qualitative and quantitative analyses.

A new second-generation supraglottic airway device (Ambu® AuraGain•) versus intubating laryngeal mask airway as conduits for blind intubation - A prospective, randomised trial

Background and Aims:

The Ambu^® AuraGain^• is a new single-use supraglottic airway device with gastric channel, designed to facilitate intubation. The study aimed to assess the success rates of proper placement and intubation using Ambu^® AuraGain^• compared with intubating laryngeal mask airway (ILMA).

Methods:

One hundred and twenty patients (18–60 years) were enrolled into this prospective, randomised, comparative study. After inducing general anaesthesia, appropriate size ILMA (group I)/Ambu^® AuraGain^• (group A) was placed as per the manufacturer's recommendations and correct placement was confirmed. Appropriate size endotracheal tube was passed through the device. The success rate of insertion and intubation, number of attempts, Cormack–Lehane grading before insertion and haemodynamics were recorded. Data were analysed using Mantel–Haenszel Chi-square test, Student's t-test and Fisher's exact test.

Results:

Demographic and airway parameters were uniformly distributed in both the groups. The success rate for insertion was 100% in both devices. The success rate for intubation was 96.6% (58/60) in group I and 36.6% in group A (P < 0.001). In group I, patients with mean thyromental distance >7.62 ± 0.75 cm had higher successful intubation compared with patients with mean thyromental distance <5.25 ± 0.35 cm (P = 0.014). Cormack–Lehane grading did not correlate with intubation attempts or success rate in group I (P = 0.45), whereas in group A the rate of successful blind intubation with Cormack–Lehane grade 1 was 50% (19/38).

Conclusion:

Both devices have 100% insertion success, though Ambu^® AuraGain^• has lower success rate for facilitating intubation compared with ILMA.

Clonidine as a Sole Epidural Adjuvant in Combined Spinal-epidural: Clinical Study

Background and Aims:

Clonidine has been used as an epidural adjuvant along with local anesthetics; however, its use as a sole epidural adjuvant in combined spinal-epidural (CSE) anesthesia has not been explored; thus, this study aimed to assess the effects of clonidine as a sole epidural adjuvant in CSE on sensory and motor characteristics of 0.5% hyperbaric bupivacaine given by subarachnoid route.

Methodology:

A total of 60 patients belonging to the American Society of Anesthesiologists Classes I and II aged 18–60 years were randomized in two groups; group G300 and group GNS. G300 group received 300 mg clonidine and GNS received normal saline through epidural route followed by 15 mg of 0.5% hyperbaric bupivacaine as subarachnoid block. Onset of sensory block (time to T10) and motor block (time to Bromage 3), level of sedation (using Modified Ramsay Sedation Score), and hemodynamic changes were recorded. Two-segment regression, duration of analgesia (time for 1^st rescue analgesia), and motor block (time to Bromage 0) were recorded. Student's t-test (two-tailed, independent) and Chi-square/Fisher's exact probability test were used for statistical analysis.

Results:

The demographic data were comparable between the groups. The onset of sensory and motor block was significantly faster in G300 (sensory-71.63 ± 4.51 s, motor-55.63 ± 2.54 s) as compared to GNS (sensory-90.13 ± 4.88 s, motor-118.43 ± 9.50 s) (P < 0.001 and < 0.001, respectively). The two-segment regression was 199.33 ± 19.11 min and 79 ± 9.77 min in G300 and GNS, respectively, (P < 0.001). Duration of analgesia was 317.90 ± 15.32 min and 207 ± 20.66 min for G300 and GNS, respectively (P < 0.001), and duration of motor block was 409.9 ± 34.87 min and 204 ± 22.79 min for G300 and GNS, respectively (P < 0.001). The side effects such as hypotension and bradycardia were statistically and clinically not significant.

Conclusion:

Clonidine used as a sole epidural adjuvant in dose of 300 mg, for infraumbilical surgeries, has significantly faster onset of sensory and motor block with prolonged duration of analgesia and motor blockade and no significant side effects on a conventional subarachnoid block performed with 0.5% hyperbaric bupivacaine.

How to write a research proposal?

Writing the proposal of a research work in the present era is a challenging task due to the constantly evolving trends in the qualitative research design and the need to incorporate medical advances into the methodology. The proposal is a detailed plan or ‘blueprint’ for the intended study, and once it is completed, the research project should flow smoothly. Even today, many of the proposals at post-graduate evaluation committees and application proposals for funding are substandard. A search was conducted with keywords such as research proposal, writing proposal and qualitative using search engines, namely, PubMed and Google Scholar, and an attempt has been made to provide broad guidelines for writing a scientifically appropriate research proposal.

THE EFFECT OF A SINGLE DOSE OF MAGNESIUM SULPHATE AS AN ADJUVANT TO EPIDURAL BUPIVACAINE FOR INFRAUMBILICAL SURGERIES: A PROSPECTIVE DOUBLE-BLIND, RANDOMIZED CONTROL TRIAL

CONTEXT

Epidural anesthesia provides the advantage of segmental blockade and many adjuvants have been added to shorten the onset of action, improve the quality of analgesia and prolong the duration of analgesia. Magnesium sulphate(MgSO4) by virtue of its anti-iociceptive property has been administered by various routes.

AIM

To assess the effect of MgSO4 on the duration of onset of action of injection bupivacaine for epidural anesthesia in infraumbilical surgeries.

MATERIALS AND METHODS

A prospective, double-blind, randomized control study was conducted in 40 patients. Group M received 15 ml of bupivacaine 0.5% + 1 ml of 50 mg MgSO4 and Group C received 15 ml of bupivacaine 0.5% + 1 ml of normal saline via epidural route. Onset time of the sensory and motor blockade were the primary outcomes studied. Highest level of sensory block, time for two segment regression, hemodynamic parameters, side effects were the secondary parameters.

RESULTS

There was a significant difference between the groups in the mean onset time of sensory blockade at T8, 12.85 ± 2.32 min in Group M and 16.75 ± 1.74 min in Group C. Median level of sensory blockade was comparable. Mean onset time of motor blockade was 13.85 ± 3.28 min in Group M and 23.25 ± 3.35 min in Group C which was clinically and statistically significant. Time for two segment regression of sensory blockade was 95.75 ± 11.84 min in Group M and 55.5 ± 8.57 min in Group C which was significant. Hemodynamic parameters and side effects were comparable.

CONCLUSION

Magnesium sulphate as an adjuvant provides rapid onset of epidural anesthesia and prolongs the duration of analgesia with minimal side effects.

EFFECT OF DEXMEDETOMIDINE ON HEMODYNAMIC PARAMETERS DURING EXTUBATION. A PROSPECTIVE RANDOMIZED DOUBLE BLIND STUDY

BACKGROUND

Extubation is known to produce significant hemodynamic disturbances. There is a need to avoid increase in heart rate and blood pressure in hypertensive and cardiac patients and in vascular, neuro and intraocular surgeries.

AIMS

To study the ability of dexmedetomidine to attenuate the hemodynamic responses during extubation.

MATERIALS AND METHODS

80 patients of ASA Grade I-II aged 18-50 years received standard anesthesia. At the closure of skin incision, patients were randomly allocated to receive either dexmedetomidine 0.5 µg/kg (Group D) or saline placebo (Group C) intravenously over 10 minutes in a double-blind design. Heart rate (HR), systolic, diastolic and mean arterial pressures (SBP, DBP, MAP) were assessed before, during- and after extubation. Time to eye opening and extubation, sedation, complications such as coughing, laryngospasm, bronchospasm and desaturation were recorded.

RESULTS

HR, SBP, DBP and MAP were comparable to basal values in group D at extubation and lower than baseline values post-extubation but significant increase was noted in group C (P <0.001). Time to extubation and eye opening were prolonged in Group D (P <0.001). Incidence of hypotension was more in group D (22%) but was transient. Incidence of coughing was lower in Group D than in group C (P <0.001). Patients in group D were more sedated for 30 minutes post extubation.

CONCLUSION

Dexmedetomidine 0.5 µg/kg given before extubation attenuates hemodynamic reflexes during emergence from anesthesia without causing undue sedation, but prolongs time to extubation.

Effect of melatonin on duration of delirium in organophosphorus compound poisoning patients: A double-blind randomised placebo controlled trial

Background and Aims:

Organophosphate compound poisoning (OPCP) is associated with high incidence of delirium. Melatonin has been tried in the treatment of delirium and has shown a beneficial effect in OPCP. This study was conducted to know the effect of melatonin on duration of delirium and recovery profile in OPCP patients.

Methods:

Double-blind randomised placebo control trial in which 56 patients of OPCP confirmed by history and syndrome of OPCP with low plasma pseudocholinesterase, aged >18 years and weighing between 50 and 100 kg, and Acute Physiology and Chronic Health Evaluation II score of <20 were studied. Group M (n = 26) received tablet melatonin 3 mg and Group C (n = 30) received placebo tablet at 9 PM, every night throughout the Intensive Care Unit (ICU) stay. Delirium was assessed using the Confusion Assessment Method for ICU, thrice a day. Sedation was provided with injection midazolam, fentanyl and lorazepam. Duration of mechanical ventilation, vital parameters, ICU stay, sedative and atropine requirement, were recorded.

Results:

The time taken to be delirium free was significantly lower in Group M (6 ± 2.92 days) compared to Group C (9.05 ± 2.75 days) (P = 0.001) and prevalence of delirium was significantly decreased in Group M compared to Group C from day 3 onwards. The requirement of midazolam (Group M - 2.98 ± 4.99 mg/day, Group C - 9.68 ± 9.17 mg/day, P < 0.001) and fentanyl (Group M - 94.09 ± 170.05 μg/day, Group C - 189.33 ± 156.38 μg/day, P = 0.03) decreased significantly in Group M. There was no significant difference in the average atropine consumption (P = 0.27), duration of mechanical ventilation (P = 0.26), ICU stay (P = 0.21) and the number of patients requiring mechanical ventilation (P = 0.50).

Conclusion:

Orally given melatonin in organophosphate compound poisoning patients reduces the duration of delirium and the requirement of sedation and analgesia.

Comparative study of two doses of intrathecal dexmedetomidine as adjuvant with low dose hyperbaric bupivacaine in ambulatory perianal surgeries: A prospective randomised controlled study

Background and Aims:

Dexmedetomidine (DMT), as intrathecal adjuvant has been shown to successfully prolong duration of analgesia but delay the motor recovery. Hence, this study was designed to find out the dose of DMT which can provide satisfactory analgesia without prolonging motor block.

Methods:

A total of 50 patients scheduled for elective perianal surgeries were randomly allocated to Groups C or D (n = 25). Group D received hyperbaric bupivacaine 0.5% 4 mg + DMT 5 μg and Group C received hyperbaric bupivacaine 0.5% 4 mg + DMT 3 μg intrathecally. Onset and duration of sensory and motor blockade, duration of analgesia, time for ambulation and first urination were recorded. Adverse effects if any were noted.

Results:

Demographic characters, duration of surgery were comparable. The onset of sensory block to S1 was 9.61 ± 5.53 min in Group C compared to 7.69 ± 4.80 min in Group D (P = 0.35). Duration of sensory (145.28 ± 83.17 min – C, 167.85 ± 93.75 min – D, P = 0.5) and motor block (170.53 ± 73.44 min – C, 196.14 ± 84.28 min, P = 0.39) were comparable. Duration of analgesia (337.86 ± 105.11 min – C, 340.78 ± 101.81 min – D, P = 0.9) and time for ambulation (252.46 ± 93.72 min – C, 253.64 ± 88.04 min – D, P = 0.97) were also comparable. One patient in each group had urinary retention requiring catheterization. No other side effects were observed.

Conclusion:

Intrathecal DMT 3 μg dose does not produce faster ambulation compared to intrathecal DMT 5 μg though it produces comparable duration of analgesia for perianal surgeries.

"ANESTHETIC SPARING EFFECT OF INTRAOPERATIVE LIGNOCAINE OR DEXMEDETOMIDINE INFUSION ON SEVOFLURANE DURING GENERAL ANESTHESIA"

BACKGROUND

Lidocaine and Dexmedetomidine are known to blunt the stress response to surgery, and have anesthetic sparing activity. This study was designed to evaluate and compare the anesthetic sparing effect of intravenous lidocaine with Dexmedetomidine infusion during sevoflurane based general anesthesia and also to assess their effects on hemodynamic parameters.

METHODS

Forty-eight ASA I-II patients aged between 18-55 yr, scheduled for abdominal surgery lasting less than 2 h, performed under general anesthesia were enrolled and they were randomly allocated to Lidocaine(L), Dexmedetomidine (D) and Saline (S) groups of 16 each. Group L received Inj. Lidocaine at 1.5 mg/kg bolus over 10 min followed by infusion at 1.5 mg/ kg/hr, and Group D received Inj. Dexmedetomidine at 1 μg/kg over 10 min, followed by 0.5 μg/ kg/hr infusion till the end of surgery. Group S received similar volume of normal saline. Anesthesia was induced with Inj. Propofol and maintained with N2O in O2 and sevoflurane, keeping entropy between 40-60. The hourly sevoflurane requirements and hemodynamic parameters were recorded. Results: Demographic parameters, entropy and duration of surgery were comparable. Mean sevoflurane requirement at 1st h in group L and D were 11.6 ± 1.5 ml, and 10.2 ± 1.3 ml respectively, while it was 16.7 ± 4.1 ml in Saline group (P < 0.001). Sevoflurane requirements were significantly lesser in group D compared to group L (P = 0.009). The Mean ET(sevo) concentrations in Group L, D and S were 0.8 ± 0.3, 0.8 ± 0.4 and 1.2 ± 0.5 (P = 0.021), respectively.

CONCLUSIONS

Both drugs produce significant anesthetic sparing effect during sevoflurane based general anesthesia, but dexmedetomidine has better sparing effect than lignocaine.

Why do satellite imageries show exceptionally high chlorophyll in the Gulf of Mannar and the Palk Bay during the Norteast Monsoon?

The Gulf of Mannar (GoM) and the Palk Bay (PB) are two least studied marine environments located between India and Sri Lanka. Exceptionally high chlorophyll a concentration in the GoM and the PB during the Northeast Monsoon (November-February) is a consistent feature in satellite imageries, which has been attributed to the intrusion of the Bay of Bengal (BoB) waters. The analyses of the Moderate Resolution Imaging Spectroradiometer (MODIS) and field chlorophyll data collected from 30 locations in the Indian sector of the GoM and the PB in January 2011 showed significant overestimations in the satellite data. This error was much higher in the PB (60-80 %) as compared to the GoM (18-28 %). The multivariate analyses evidenced that the exceptionally high satellite chlorophyll in the PB is contributed largely by turbidity, colored dissolved organic matter (CDOM), and bottom reflectance. The paper cautions that though MODIS is superior in estimating chlorophyll a in optically complex waters, there are still chances of overestimations in regions like the PB.

Source investigation of the tar balls deposited along the Gujarat coast, India, using chemical fingerprinting and transport modeling techniques

Deposition of tar balls (TBs) along the south Gujarat coast, situated on the west coast of India (WCI), commonly occurs during the southwest monsoon season. Several offshore oil fields off the Mumbai-Gujarat coast, and refineries along the coast might be sources of oil spills/leakages and lead to the formation of TBs. To identify the sources, we collected 12 TB samples from the beaches of Gujarat (Tithal, Maroli, Umbergam, and Nargol) during 15-17 July 2012 as well as samples of crude oils, namely, Cairn, NIKO, MSC Chitra, and two at Bombay High (BH). These TBs were subject to the following multimarker approach for source identification: Diagnostic Ratios of n-alkanes, polycyclic aromatic hydrocarbons, pentacyclic triterpanes, compound specific isotope analysis, Principle Component Analysis and numerical simulations (hydrodynamic model coupled with particle trajectories). The chemical fingerprint results reveal that the source of the TBs is BH crude oils, and the model results confirm that the source location is BH north oil fields. This is the first study of its kind in India to use fingerprinting and transport modeling techniques for source identification of TBs.

Effect of intraoperative Dexmedetomidine infusion on Sevoflurane requirement and blood glucose levels during entropy-guided general anesthesia

Background:

Dexmedetomidine has been shown to blunt the stress response to surgery. Hence a study was designed to evaluate the effect of intravenous (IV) Dexmedetomidine infusion during general anesthesia for abdominal surgeries on blood glucose levels and on Sevoflurane requirements during anesthesia.

Materials and Methods:

Forty patients scheduled for abdominal surgery under general anesthesia were divided into Dexmedetomidine (D) group and Placebo (P) group of 20 each. Group D received a loading dose of Inj. Dexmedetomidine at 1 μg/kg/10 min diluted to 20 mL, followed by maintenance with 0.5 μg/kg/h., till the end of surgery. Group P received similar volume of IV normal saline. Anesthesia was maintained with nitrous oxide in oxygen and Sevoflurane keeping entropy between 40 and 60. Data were analyzed using students t test, chi square test and Fisher Exact test as applicable.

Results:

During the first postoperative hour, Dexmedetomidine group showed blood glucose levels of 118.2 ± 16.24 mg/dL, compared to placebo group which was 136.95 ± 19.76 mg/dL and it was statistically significant (P < 0.01). Mean hourly Sevoflurane requirement in Group D was 11.10 ± 2.17 mL, compared to 15.45 ± 3.97 mL in placebo group. In peri-operative period, the heart rate and MAP were significantly lower in Group D, when compared to placebo. Patients in Group D were better sedated and post-operative pain score was better in Group D compared to Group P.

Conclusion:

IV Dexmedetomidine was effective in blunting stress response to surgical trauma as indicated by lower blood glucose levels, and reduces Sevoflurane requirements during entropy guided general anesthesia without affecting time for extubation.

Effect of supplementation of low dose intravenous dexmedetomidine on characteristics of spinal anaesthesia with hyperbaric bupivacaine

Aims:

Intravenous (IV) dexmedetomidine with excellent sedative properties has been shown to reduce analgesic requirements during general anaesthesia. A study was conducted to assess the effects of IV dexmedetomidine on sensory, motor, haemodynamic parameters and sedation during subarachnoid block (SAB).

Methods:

A total of 50 patients undergoing infraumbilical and lower limb surgeries under SAB were selected. Group D received IV dexmedetomidine 0.5 mcg/kg bolus over 10 min prior to SAB, followed by an infusion of 0.5 mcg/kg/h for the duration of the surgery. Group C received similar volume of normal saline infusion. Time for the onset of sensory and motor blockade, cephalad level of analgesia and duration of analgesia were noted. Sedation scores using Ramsay Sedation Score (RSS) and haemodynamic parameters were assessed.

Results:

Demographic parameters, duration and type of surgery were comparable. Onset of sensory block was 66±44.14 s in Group D compared with 129.6±102.4 s in Group C. The time for two segment regression was 111.52±30.9 min in Group D and 53.6±18.22 min in Group C and duration of analgesia was 222.8±123.4 min in Group D and 138.36±21.62 min in Group C. The duration of motor blockade was prolonged in Group D compared with Group C. There was clinically and statistically significant decrease in heart rate and blood pressures in Group D. The mean intraoperative RSS was higher in Group D.

Conclusion:

Administration of IV dexmedetomidine during SAB hastens the onset of sensory block and prolongs the duration of sensory and motor block with satisfactory arousable sedation.

Trajectory of an oil spill off Goa, eastern Arabian Sea: field observations and simulations

An oil spill occurred off Goa, west coast of India, on 23 March 2005 due to collision of two vessels. In general, fair weather with weak winds prevails along the west coast of India during March. In that case, the spill would have moved slowly and reached the coast. However, in 2005 when this event occurred, relatively stronger winds prevailed, and these winds forced the spill to move away from the coast. The spill trajectory was dominated by winds rather than currents. The MIKE21 Spill Analysis model was used to simulate the spill trajectory. The observed spill trajectory and the slick area were in agreement with the model simulations. The present study illustrates the importance of having pre-validated trajectories of spill scenarios for selecting eco-sensitive regions for preparedness and planning suitable response strategies whenever spill episodes occur.

Thermohaline structure of an inverse estuary--The Gulf of Kachchh: measurements and model simulations

The Gulf of Kachchh (GoK) is situated in the northeastern Arabian Sea. The presence of several industries along its coastal belt makes GoK a highly sensitive coastal ecosystem. In the present study, an attempt is made for the first time to study GoK thermohaline structure and its variability, based on field measurements and model simulations. Though GoK is considered as a well-mixed system, the study reveals that only the central Gulf is well mixed. Vertical gradients in temperature and salinity fields are noticed in the eastern Gulf, where a cold and high saline tongue is observed in the subsurface layers. Salinity indicates the characteristic feature of an inverse estuary with low values (37.20 psu) near the mouth and high values (>40.0 psu) near the head of the Gulf. The model simulated temperature and salinity fields exhibit semidiurnal oscillations similar to that of field observations. Model results show cold, high saline waters advecting from the east during ebb forming a transition zone, which oscillates with tides. A high salinity tongue is seen in the bottom layer, indicating a westward flowing bottom current. The transient zone acts as an dynamic barrier, and plays a vital role in the pollutant transport.

Tidal eddies in a semi-enclosed basin: a model study

A modeling study has been carried out to support a Marine Management Plan for the Gulf of Kachchh, India and here the hydrodynamic part of the programme is described. The hydrodynamic model accurately predicts the tides and tidal currents present in the Gulf and these have been validated with the measured data, albeit at only a few locations. The time averaged residual currents obtained from the model for one lunar cycle clearly reproduce the complex, small-scale, topographically induced flows with several eddies. The existence of a dynamic barrier along Sikka-Mundra section, which divides the Gulf into two distinct dynamic systems, is very evident. The model is further used to predict the movement of surface floating particles launched at different locations in the Gulf, as an aid to determining floating pollutants. The results indicate that industries discharging wastes upstream of the barrier should use extreme caution, as these will remain in the vicinity for at least one lunar cycle.