Comparison of phenylephrine and norepinephrine for treatment of spinal hypotension during elective cesarean delivery- A randomised, double-blind study.

Background and Aims: Hypotension following subarachnoid block for cesarean delivery (CD) is common. We compared the effect of bolus administration of norepinephrine and phenylephrine on umbilical artery pH (primary objective) and their efficacy for the treatment of maternal hypotension (secondary objective) in term parturients undergoing elective CD under spinal anesthesia. Material and Methods: In a randomized, double-blinded study, parturients received 1 mL boluses of either phenylephrine 100 µg/mL (group phenylephrine; n = 45) or norepinephrine 7.5 µg/mL (group norepinephrine; n = 45) whenever maternal systolic blood pressure decreased to ≤80% of baseline. Maternal hemodynamic changes, vasopressor, and atropine requirement and neonatal outcome (umbilical cord blood gas analysis, Apgar scores, neonatal neurobehavioral response) were assessed. Results: The Apgar scores and umbilical cord blood gas analysis were comparable between groups. The neurobehavioral scale score was significantly higher in group NE compared with that in group PE at 24 h and 48 h; P = 0.007 and 0.002, respectively. The number of vasopressor doses and time to the first vasopressor requirement for maintaining systolic pressure >80% of baseline was comparable in both groups. Incidence of bradycardia (P = 0.009), reactive hypertension (P = 0.003), and dose requirement of atropine (P = 0.005) was higher in group PE compared with group NE. Conclusions: In term normotensive parturients who received bolus norepinephrine 7.5 µg or phenylephrine 100 µg for the treatment of post-spinal hypotension during CD, neonatal umbilical cord blood gas analysis and Apgar scores were comparable. Norepinephrine use was associated with a lower incidence of maternal bradycardia and reactive hypertension compared with phenylephrine.

Airway management in maxillofacial trauma.

Airway management of patients with maxillofacial trauma remains a challenging task for an anesthesiologist in the emergency and perioperative settings due to anatomical distortion. Detailed knowledge of maxillofacial and airway anatomy is desired for the correct diagnosis of extent and severity of the injury. Basic principles of advanced trauma life support protocols should be followed while managing such patients. Establishing unobstructed airway remains the top priority while maintaining C-spine immobilization and preventing aspiration. Although multiple options exist for securing the airway, a universal technique of airway management may not be applicable to all the patients. Hence, a high index of suspicion along with timely and skillful management is warranted. In this brief review, issues affecting the airway management in cases of maxillofacial trauma are addressed with the possible uses of a wide range of airway management devices available in emergency and elective scenarios.

Factors predicting difficult spinal block: A single centre study.

BACKGROUND AND AIMS: Several factors determine the success of dural puncture. We aimed to assess the association of first puncture success and number of attempts with characteristics of the patient, provider, technique and equipment. MATERIAL AND METHODS: This prospective, observational study was performed in 1647 adult patients undergoing surgery under spinal anesthesia. Patient characteristics, anatomical landmarks, spinal bony deformity, provider experience, technique, skin punctures, needle redirections, subarachnoid space depth, and complications, if any, were noted. Difficult dural puncture was assessed by first puncture success and number of attempts (skin punctures plus needle redirections) required for successful needle placement. RESULTS: First puncture success was obtained in 872 (52.9%) patients. Failed dural puncture occurred in 4 (0.2%) of 1647 patients. Multivariate logistic regression analysis revealed that longer distance from C7 vertebral spine to tip of coccyx (P = 0.04), lower subarachnoid space depth (P = 0.001), good quality of bony landmarks (P = 0.001) and absence of crowded spine (P = 0.02) were associated with first puncture success. Male gender, poor or no spinal landmarks, presence of bony deformity and lower level of provider's experience predicted increased number of attempts for successful dural puncture. CONCLUSION: First puncture success of spinal block was influenced only by patient's anatomical factors, whereas the number of attempts required for successful block were predicted by both provider and patient factors.

Evaluation of the efficacy of desflurane with or without labetalol for hypotensive anesthesia in middle ear microsurgery.

BACKGROUND AND AIMS: Hypotensive anesthesia technique is used to reduce intraoperative bleeding and to improve the visibility of the operative field. The aim was to evaluate the efficacy of desflurane with and without labetalol for producing hypotensive anesthesia. MATERIAL AND METHODS: Sixty adult patients undergoing elective middle ear surgery were administered general anesthesia and randomly divided into two groups - Group D and Group L. The target mean arterial pressure (MAP) was 55-65 mmHg during hypotensive period. Group D patients received an increasing concentration of desflurane alone. Group L patients received 3% desflurane plus labetalol (loading dose 0.3 mg/kg intravenously, followed by 10 mg increments every 10 min). Student's t-test and paired t-test were used to compare the hemodynamic parameters. Visibility of the operative field, anesthetic and rescue drug requirement, partial pressure of oxygen in arterial blood, time taken for induction and reversal of hypotension and recovery characteristics were noted. RESULTS: Target MAP was achieved in both the groups. Group D was associated with a higher mean heart rate compared with Group L (77.3 ± 11.0/min vs. 70.5 ± 2.5/min, respectively; P < 0.001) during the hypotensive period, along with a higher requirement for desflurane (P = 0.000) and metoprolol (P = 0.01). Time taken to achieve target MAP was lesser in Group L compared with Group D (33.7 ± 7.1 vs. 39.8 ± 6.2 min, respectively; P = 0.000). Time taken to return to baseline MAP was faster in Group D (P = 0.03). Emergence time was longer with desflurane alone (P = 0.000) resulting in greater sedation (P = 0.000) in the immediate postoperative period. CONCLUSION: Although desflurane is effective for inducing deliberate hypotension in middle ear microsurgery, the combination of desflurane with labetalol is associated with decreased requirement of desflurane, absence of reflex tachycardia, faster induction of hypotension, faster recovery from anesthesia, and less postoperative sedation.

Unilateral pulmonary edema during laparoscopic resection of adrenal tumor.

Despite technological, therapeutic and diagnostic advancements, surgical intervention in pheochromocytoma may result in a life-threatening situation. We report a patient who developed unilateral pulmonary edema during laparoscopic resection of adrenal tumor.

Cardiac dysrhythmia complicating total parotidectomy.

Sudden severe dysrhythmias during anaesthesia can be life- threatening for the patient. We describe a case in which ventricular dysrhythmias and severe bradycardia occurred during dissection and mobilization of the deep lobe of the parotid gland during total parotidectomy under general anaesthesia. We believe that these dysrhythmias were caused by a trigemino- vagal reflex similar to the oculocardiac reflex, but with afferent innervation from mandibular division of the trigeminal nerve. The case report is presented to illustrate a possible existence and importance of reflex bradycardic responses that may occur during surgical procedures involving the parotid gland.

Evaluation of thyromental height as a predictor of difficult laryngoscopy and difficult intubation: a cross-sectional observational study.

BACKGROUND AND OBJECTIVES: Several anthropometric measurements have been suggested to identify a potentially difficult airway. We studied thyromental height (TMH) as a predictor of difficult laryngoscopy and difficult intubation. We also compared TMH, ratio of height to thyromental distance (RHTMD), and thyromental distance (TMD) as predictors of difficult airway. METHODS: This cross-sectional observational study was conducted in 300 adult surgical patients requiring tracheal intubation. Preoperatively airway characteristics were assessed. Standard anesthesia was administered. Degree of difficulty with mask ventilation, laryngoscopic view, duration of laryngoscopy, and difficulty in tracheal intubation (intubation difficulty scale score) were noted. Multivariate logistics regression analysis was performed to identify independent predictors for difficult laryngoscopy. RESULTS: Laryngoscopy was difficult in 46 of 300 (15.3%) patients; all 46 patients had Cormack-Lehane grade 3 view. Duration of laryngoscopy was 27........11...s in patients with difficult laryngoscopy and 12.7........3.9...s in easy laryngoscopy; p...=...0.001. Multivariate analysis identified that TMH, presence of short neck, and history of snoring were independently associated with difficult laryngoscopy. Incidence of difficult intubation was 17.0%. A shorter TMH was associated with higher IDS scores; r...=...-0.16, p...=...0.001. TMH and duration of laryngoscopy were found to be negatively correlated; a shorter TMH was associated with a longer duration of laryngoscopy; r...=...-0.13, p...=...0.03. The cut-off threshold value for TMH in our study is 4.4 cm with a sensitivity of 66% and a specificity of 54%. CONCLUSION: Thyromental height predicts difficult laryngoscopy and difficult intubation. TMD and RHTMD did not prove to be useful as predictors of difficult airway.

Effect of Pre-Treatment with a Combination of Fentanyl and Midazolam for Prevention of Etomidate-Induced Myoclonus.

OBJECTIVE: Pre-treatment with either fentanyl or midazolam has previously been used to prevent etomidate-induced myoclonus (EIM). The aim of the present study was to determine the effect of pre-treatment with a combination of midazolam and fentanyl in reducing the incidence and severity of EIM. METHODS: This prospective, randomised, double-blind study was conducted on 210 surgical patients allocated to three study groups. Group F patients received fentanyl 2 µg kg-1 and 5 mL saline. Group M patients received midazolam 0.03 mg kg-1 and 5 mL saline. Group FM patients received fentanyl 2 µg kg-1 plus midazolam 0.03 mg kg-1. The study drugs were administered intravenously over 30 s. Five minutes after study drug administration, etomidate 0.3 mg kg-1 was administered over 60 s. Patients were observed for 1 min for occurrence and severity of EIM. RESULTS: The incidence of EIM was 34/70 (48.6%), 55/70 (78.6%) and 11/70 (15.7%) in groups F, M and FM, respectively (p=0.001). Myoclonus of moderate or severe grade occurred in 23/70 (32.9%), 45/70 (64.3%) and 6/70 (8.6%) in groups F, M and FM, respectively (p=0.001). Patients who experienced myoclonus exhibited a significantly higher percentage change in post-induction heart rate (p=0.02), systolic blood pressure (p=0.001) and mean blood pressure (p=0.001) from pre-induction values than those who did not. CONCLUSION: Pre-treatment with a combination of fentanyl and midazolam is more effective than that with fentanyl or midazolam alone in reducing the incidence and severity of EIM. Myoclonus is associated with a higher post-induction haemodynamic variation.

The effect of injection speed on the spinal block characteristics of hyperbaric bupivacaine 0.5% in the elderly.

PURPOSE: The purpose of this prospective, randomized, double-blind study was to compare anesthetic characteristics after two speeds of intrathecal injection of hyperbaric bupivacaine in elderly patients. METHODS: Fifty-six patients, aged ≥65 years, undergoing transurethral surgery under spinal anesthesia were allocated randomly to two groups according to rate of intrathecal injection of 2 ml hyperbaric bupivacaine 0.5%: group Fast (maximum possible rate; mean 0.38 ml/s) n = 26; group Slow (over 40 s; 0.05 ml/s), n = 25. Spinal blocks were administered in the lateral position. Data collection at different times included sensory level, motor block, hemodynamic changes, and occurrence of neurological symptoms. RESULTS: There was no significant difference between the groups regarding maximum sensory anesthetic level achieved (group Fast: T7 (T4-T10), median (range); group Slow T8 (T6-T10), P = 0.184); times (min) to reach (a) T10 sensory level (group Fast 5.3 ± 4.2 (mean ± SD), group Slow 8.0 ± 6.5, P = 0.093); (b) maximum sensory level (group Fast 11.6 ± 4.7; group Slow 13.6 ± 6.1, P = 0.199); and (c) 2-segment regression of anesthesia (group Fast 92.2 ± 29.6; group Slow 104.7 ± 36.1, P = 0.182). Degree and duration of motor block were similar (P = 0.947 and P = 0.895, respectively). Hemodynamic changes, ephedrine and atropine requirement, incidence of postoperative neurological symptoms after 24 h and 1 week were similar (all P > 0.05). CONCLUSIONS: An eightfold difference in speed of intrathecal injection of 0.5% hyperbaric bupivacaine did not affect the clinical characteristics of spinal anesthesia in elderly patients undergoing transurethral surgery.

Clinical Implications of Vocal Cord-Carina Distance and Tracheal Length in the Indian Population.

OBJECTIVE: Securing the tracheal tube (TT) at a fixed recommended depth of 21/23 cm in female and male patients, respectively, may result in inappropriate placement of the TT in some patients. The aim of the present study was to determine the vocal cord-carina distance (VCD) and tracheal length (TL) to ascertain the optimal depth of TT placement during orotracheal intubation in the adult Indian population. METHODS: A total of 92 adults undergoing elective surgery under general anaesthesia with orotracheal intubation were studied. Surface anatomy airway measurements were noted. A cuffed TT (female size 7 mm ID and male size 8 mm ID) was inserted with the intubation guide mark at level with the vocal cords (VCs). Fiberoptic bronchoscopy-guided measurements were obtained for VCD, TL, TT tip-carina distance, VC-cricoid distance and lip-carina (L-C) distance. RESULTS: The mean±SD VCD was 12.82±2.05 and 12.02±1.44 cm, and TL was 10.14±2.04 and 9.37±1.28 cm in male and female patients, respectively. Statistically significant differences were observed between male and female patients in VCD (p=0.033), TL (p=0.032), L-C distance (p<0.001) and lip-TT tip distance (p<0.001); lip-TT tip distance was 19.50±1.39 cm in male patients and 18.17±1.28 cm in female patients. The L-C distance correlated with patient height, weight and neck length. L-C distance=7.214+0.049×Height+0.320×Neck length+0.033×Weight. CONCLUSION: We recommend placing the TT with its proximal guide mark at the level of VCs in the Indian population. The 21/23 cm rule for tube placement depth in female and male patients, respectively, cannot be routinely followed in the Indian population.