Smita Prakash

Patient-controlled analgesia with fentanyl for burn dressing changes.

In this randomized, double-blinded study in 60 ASA I or II adults with >20% body-surface area thermal burns, we investigated the feasibility of patient-controlled analgesia (PCA) with fentanyl for pain management during dressing changes and determined the optimal PCA-fentanyl demand dose. An initial loading dose of IV fentanyl 1 μg/kg was administered. Patients received on-demand analgesia with fentanyl (10, 20, 30, and 40 μg) whenever their visual analog scale (VAS) score was >2. Mean VAS scores in the 10 and 20 μg groups (7.73 ± 1.33 and 7.20 ± 1.21, respectively) were significantly higher than those in the 30 and 40 μg groups (4.47 ± 0.83 and 3.90 ± 0.63, respectively) (all P = 0.000). Demand/delivery ratios were significantly larger in the 10 and 20 μg groups (3.03 ±1.06 and 2.54 ± 0.49, respectively) than those in the 30 and 40 μg groups (1.36 ±0.34 and 1.37 ±0.36, respectively) (all P =0.000). VAS scores and demand/delivery ratios were comparable in the 30 and 40 μg groups (P = 0.260 and P = 0.977, respectively), which suggests comparable analgesic efficacy. There was no hemodynamic instability or respiratory depression. The optimal demand dose of PCA-fentanyl was 30 μg (5-min lockout interval) after an initial loading dose of IV fentanyl 1 μg/kg.

Analgesic Efficacy of Two Doses of Intrathecal Midazolam With Bupivacaine in Patients Undergoing Cesarean Delivery

Objectives: In this prospective, randomized, double-blind, placebo-controlled study, we investigated the postoperative analgesic efficacy of 2 doses of intrathecal midazolam as an adjunct to bupivacaine for spinal anesthesia. Methods: Sixty patients undergoing elective cesarean delivery under spinal anesthesia were allocated randomly to 3 groups: group B, 2 mL hyperbaric bupivicaine 0.5%; group BM1, 2 mL bupivacaine plus midazolam 1 mg (preservative free); and group BM2, 2 mL bupivicaine plus midazolam 2 mg. Results: The mean duration of postoperative analgesia (determined by request for rescue medication) was 3.8 ± 0.5 hours in group B compared with 4.3 ± 0.7 hours in group BM1 (P = .18), and 6.1 ± 1.0 hours in group BM2 (P = .001). Supplemental analgesic requirements with diclofenac were significantly less in group BM2 (93 ± 29 mg) compared with group B (145 ± 12 mg) and group BM1 (148 ± 16 mg, P < .001). Time to block regression was longer in group B (182 ± 30 minutes) compared with group BM1 (152 ± 32 minutes) and group B (126 ± 20 minutes) (both P < .001). Arterial pressure, heart rate, oxygen saturation, sedation score, and time to first void were comparable between groups. Group B had a significantly higher incidence of nausea and vomiting than groups BM1 and BM2 (P = .02). No neurologic deficits were observed. Conclusions: Intrathecal midazolam 2 mg provided a moderate prolongation of postoperative analgesia when used as an adjunct to bupivacaine in patients undergoing cesarean delivery. Intrathecal midazolam, 1 mg and 2 mg, decreased postoperative nausea and vomiting.

Maternal and neonatal effects of bolus administration of ephedrine and phenylephrine during spinal anaesthesia for caesarean delivery: a randomised study

BACKGROUND Maternal haemodynamic changes and neonatal well-being following bolus administration of ephedrine and phenylephrine were compared in 60 term parturients undergoing elective caesarean delivery under spinal anaesthesia. METHODS In a randomised double-blind study, women received boluses of either ephedrine 6 mg (group E; n=30) or phenylephrine 100 microg (group P; n=30) whenever maternal systolic pressure was 80% of baseline. RESULTS Changes in systolic pressure were comparable in the two groups. There were no differences in the incidence of bradycardia (group E: 0% vs. group P: 16.7%; P>0.05), nausea (group E: 13% vs. group: P 0; P>0.05) and vomiting (group E: 3.3% vs. group P: 0; P>0.05). Umbilical artery (UA) pH (group E: 7.29 +/- 0.04 vs. group P: 7.32 +/- 0.04; P=0.01) and venous pH (group E: 7.34 +/- 0.04 vs. group P: 7.38 +/- 0.05; P=0.002) were significantly greater in group P than in group E. UA base excess was significantly less in group E (-2.83 +/- 0.94 mEq/L) than in group P (-1.61 +/- 1.04 mEq/L; P<0.001). Apgar scores at 1, 5 and 10min and neurobehavioural scores at 2-4 h, 24 h and 48 h were similar in the two groups (P>0.05). CONCLUSIONS Phenylephrine 100 mug and ephedrine 6 mg had similar efficacy in the treatment of maternal hypotension during spinal anaesthesia for elective caesarean delivery. Neonates in group P had significantly higher umbilical arterial pH and base excess values than those in group E, which is consistent with other studies.

A combination of fentanyl‐midazolam‐propofol provides better intubating conditions than fentanyl‐lignocaine‐propofol in the absence of neuromuscular blocking agents

Background:  The use of propofol and adjuvants such as opioids, benzodiazepines and local anaesthetic agents, may provide adequate conditions for tracheal intubation without the need for neuromuscular blocking agents. In this randomized, double‐blind study, intubating conditions after induction of anaesthesia with propofol, midazolam and fentanyl were compared with those after propofol, lignocaine and fentanyl.

Comparative Evaluation of the Sniffing Position with Simple Head Extension for Laryngoscopic View and Intubation Difficulty in Adults Undergoing Elective Surgery

The effect of patient position on mask ventilation, laryngoscopic view, intubation difficulty, and the stance adopted by the anesthesiologist during laryngoscopy and tracheal intubation was investigated in 546 anesthetized adults in this prospective, randomized study. Patients were randomly assigned to either the sniffing position group or the simple extension group. The distribution of Cormack grades was comparable between the two groups (P = 0.144). The IDS score [median (IQR)] was 0 (0–2) in the sniffing group and 1 (0–2) in the simple extension group; P = 0.002. There were significant differences between groups with regard to intensity of lifting force, external laryngeal manipulation, alternate techniques used, number of attempts, and the stance adopted by anesthesiologist. We conclude that the sniffing position is superior to simple head extension with regard to ease of intubation as assessed by IDS. An upright stance is adopted by more anesthesiologists performing intubation with patients in the sniffing position.

Difficult laryngoscopy and intubation in the Indian population: An assessment of anatomical and clinical risk factors

Background and Aim: Differences in patient characteristics due to race or ethnicity may influence the incidence of difficult airway. Our purpose was to determine the incidence of difficult laryngoscopy and intubation, as well as the anatomical features and clinical risk factors that influence them, in the Indian population. Methods: In 330 adult patients receiving general anaesthesia with tracheal intubation, airway characteristics and clinical factors were determined and their association with difficult laryngoscopy (Cormack and Lehane grade 3 and 4) was analysed. Intubation Difficulty Scale score was used to identify degree of difficult laryngoscopy. Results: The incidence of difficult laryngoscopy and intubation was 9.7% and 4.5%, respectively. Univariate analysis showed that increasing age and weight, male gender, modified Mallampati class (MMC) 3 and 4 in sitting and supine positions, inter-incisor distance (IID) ≤3.5 cm, thyromental (TMD) and sternomental distance, ratio of height and TMD, short neck, limited mandibular protrusion, decreased range of neck movement, history of snoring, receding mandible and cervical spondylosis were associated with difficult laryngoscopy. Multivariate analysis identified four variables that were independently associated with difficult laryngoscopy: MMC class 3 and 4, range of neck movement <80°, IID ≤ 3.5 cm and snoring. Conclusions: We found an incidence of 9.7% and 4.5% for difficult laryngoscopy and difficult intubation, respectively, in Indian patients with apparently normal airways. MMC class 3 and 4, range of neck movement <80°, IID ≤ 3.5 cm and snoring were independently related to difficult laryngoscopy. There was a high incidence (48.5%) of minor difficulty in intubation.

Sternomental distance and sternomental displacement as predictors of difficult laryngoscopy and intubation in adult patients

Background: Several morphometric airway measurements have been used to predict difficult laryngoscopy (DL). This study evaluated sternomental distance (SMD) and sternomental displacement (SMDD, difference between SMD measured in neutral and extended head position), as predictors of DL and difficult intubation (DI). Materials and Methods: We studied 610 adult patients scheduled to receive general anesthesia with tracheal intubation. SMD, SMDD, physical, and airway characteristics were measured. DL (Cormack-Lehane grade 3/4) and DI (assessed by Intubation Difficulty Scale) were evaluated. The optimal cut-off points for SMD and SMDD were identified by using receiver operating characteristic (ROC) analysis. Multivariate logistic regression was used to predict DL and ROC curve was used to assess accuracy on developed regression model. Results: The incidence of DL and DI was 15.4% and 8.3%, respectively. The cut-off values for SMD and SMDD were ≤14.75 cm (sensitivity 66%, specificity 60%) and ≤5.25 cm (sensitivity 70%, specificity 53%), respectively, for predicting DL. The area under the curve (AUC) with 95% confidence interval (CI) for SMD was 0.66 (0.60–0.72) and that for SMDD was 0.687 (0.63–0.74). Multivariate analysis with logistic regression identified inter-incisor distance, neck movement <80°, SMD, SMDD, short neck and history of snoring as predictors and the predictive model so obtained exhibited a higher diagnostic accuracy (AUC: 0.82; 95% CI 0.77–0.86). SMDD, but not SMD, correlated with DI. Conclusions: Both SMD and SMDD provide a rapid, simple, objective test that may help identifying patients at risk of DL. Their predictive value improves considerably when combined with the other predictors identified by logistic regression.

Airway management in patients with burn contractures of the neck

Airway management of patients with burn contracture of the neck (PBC neck) is a challenge to the anesthesiologist. Patient evaluation includes history, physical and airway examination. A safe approach in the airway management of a patient with moderate to severe PBC neck is to secure the airway with the patient awake. The anesthesiologist should have a pre-planned strategy for intubation of the difficult airway. The choices advocated for airway management of such patients include awake fiberoptic-guided intubation, use of intubating laryngeal mask airway, intubation without neuromuscular blocking agents, intubation with neuromuscular blocking agents after testing the ability to ventilate by mask, pre-induction neck scar release under local anesthesia and ketamine or sedation followed by direct laryngoscopy and intubation and video-laryngoscope guided intubation, amongst others. Preparation of the patient includes an explanation of the proposed procedure, sedation, administration of antisialogogues and regional anesthesia of the airway. The various options for intubation of patients with PBC neck, intraoperative concerns and safe extubation are described. Back-up plans, airway rescue strategies and a review of literature on this subject are presented.

Neurotoxin envenomation mimicking brain death in a child: A case report and review of literature.

The spectrum of presentation of a victim of neurotoxic snake bite can range from mild ptosis to complete paralysis and ophthalmoplegia. We report a case of snake bite in a 10-year-old child who was comatosed with bilateral fixed dilated pupils and absent doll′s eye movement that was interpreted as brain death. Physicians need to be aware of the likelihood of snakebite presenting as locked in syndrome.

A prospective observational study of skin to subarachnoid space depth in the Indian population.

Background and Aims: A pre-puncture estimate of skin to subarachnoid space depth (SSD) may guide spinal needle placement and reduce complications associated with lumbar puncture. Our aim was to determine (1) The SSD in Indian males, females, parturients and the overall population; (2) To derive formulae for predicting SSD and (3) To determine which previously suggested formula best suited our population. Methods: In this prospective, observational study, 800 adult Indian patients undergoing surgery under spinal anaesthesia were divided into three groups: Males (Group M), females (Group F) and parturients (Group PF). SSD was measured after lumbar puncture. The relationship between SSD and patient characteristics was studied and statistical models were used to derive formula for predicting SSD. Statistical analysis included One-way ANOVA with post hoc analysis, forward stepwise multivariate regression analysis and paired t-tests. Results: Mean SSD was 4.71 ± 0.70 cm in the overall population. SSD in adult males (4.81 ± 0.68 cm) was significantly longer than that observed in females (4.55 ± 0.66 cm) but was comparable with SSD in parturients (4.73 ± 0.73 cm). Formula for predicting SSD in the overall population was 2.71 + 0.09 × Body Mass Index (BMI). Stocker′s formula when applied correlated best with the observed SSD. Formulae were derived for the three groups. Conclusions: We found gender-based differences in SSD, with SSD in males being significantly greater than that observed in the female population. SSD correlated with BMI in the parturient and the overall population. Amongst the previously proposed formulae, Stocker′s formula was most accurate in predicting SSD in our population.