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.

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

Abstract 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.

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.

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.

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.

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.

Clinical Evaluation of the Cricoid Pressure Effect on Bag Mask Ventilation, ProSeal Laryngeal Mask Airway Placement and Ventilation.

OBJECTIVE: Supraglottic airway devices can be life-saving in the 'cannot intubate, cannot oxygenate' situation. The cricoid pressure (CP) is considered critical in the prevention of aspiration. The aim of this self-controlled study was to evaluate the effect of CP on the bag mask ventilation (BMV), and the placement of and the ventilation through, the ProSeal laryngeal mask airway (LMA). METHODS: In 60 adult patients undergoing elective surgery, after induction of anaesthesia, the effect of bimanual CP (≈30N) on BMV, ventilation through the ProSeal LMA, its anatomic position and airway seal pressures were evaluated. CP was released, the ProSeal LMA was reseated (appropriate position), the above assessments were repeated, and the effect of CP on the tidal volume (TV) and peak inspiratory pressure (PIP) was noted. RESULTS: Out of 60 patients, the bag mask ventilation with CP was adequate in 25 (41.7%) patients compared to 59 (98.3%) patients without CP; p<0.001. The ventilation via the ProSeal LMA with CP was excellent, adequate and impossible in 0.0% (0), 49.2% (29) and 50.8% (30) patients, respectively, compared to 93.3% (56), 6.7% (4), 0% (0) patients, respectively, without CP; p<0.001. Releasing CP and advancing the ProSeal LMA to its appropriate position significantly improved the ventilation and anatomic position scores; both p<0.001. Airway seal pressures improved significantly without CP compared to with CP; p<0.001). With the ProSeal LMA in a proper position, the CP application resulted in a significant decrease in the mean expired TV (489.14±91.62 vs. 355.08±104.42 mL) with an increase in PIP (16.72±5.01 vs. 30.71±6.74 cmH2O); both p<0.001. CONCLUSION: The application of bimanual CP (≈30N) interferes with the bag mask ventilation and prevents both the correct placement and ventilation via the ProSeal LMA in adult patients.

Comparison of priming versus slow injection for reducing etomidate-induced myoclonus: a randomized controlled study.

BACKGROUND: Etomidate injection is often associated with myoclonus. Etomidate injection technique influences the incidence of myoclonus. This study was designed to clarify which of the two injection techniques-slow injection or priming with etomidate-is more effective in reducing myoclonus. METHODS: This prospective randomized controlled study was conducted on 189 surgical patients allocated to three study groups. Control group (Group C, n = 63) received 0.3 mg/kg etomidate (induction dose) over 20 s. Priming group (Group P, n = 63) received pretreatment with 0.03 mg/kg etomidate, followed after 1 min by an etomidate induction dose over 20 s. Slow injection group (Group S, n = 63) received etomidate (2 mg/ml) induction dose over 2 min. The patients were observed for occurrence and severity of myoclonus for 3 min from the start of injection of the induction dose. RESULTS: The incidence of myoclonus in Group P (38/63 [60.3%], 95% CI: 48.0-71.5) was significantly lower than in Group C (53/63 [84.1%], 95% CI: 72.9-91.3, P = 0.003) and Group S (49/63 [77.8%], 95% CI: 66.0-86.4, P = 0.034). Myoclonus of moderate or severe grade occurred in significantly more patients in Group C (68.3%) than in Group P (36.5%, P < 0.001) and Group S (50.8%, P = 0.046), but the difference between Groups P and S was not significant (P = 0.106). CONCLUSIONS: Priming is more effective than slow injection in reducing the incidence of myoclonus, but their effects on the severity of myoclonus are comparable.

Safe Labeling Practices to Minimize Medication Errors in Anesthesia: 5 Case Reports and Review of the Literature.

Drug error is a significant hazard to patient health. Poor, incorrect, and inconsistent labeling of injectable medicines and fluids, and the devices used to deliver these, has been identified as a patient safety issue. We report 5 cases of medication error as a consequence of incorrect or inappropriate labeling and analyze their cause. Recommendations for safe and practical labeling practices in anesthesia based on a review of the literature are presented. Implementation of the recommended labeling practices can reduce the risk of medication error and contribute to the safe administration of drugs.

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.

Alcohol increases bonding between the tracheal tube and the tracheal tube connector.

The tracheal tube (TT) connector needs to be firmly seated in both the TT and the breathing circuit to prevent disconnection during use. However, at times, the connector may loosen from its connection into the TT, increasing the likelihood of disconnection. We report a very simple yet useful technique to circumvent this problem.

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.

Consent and the Indian medical practitioner.

Consent is a legal requirement of medical practice and not a procedural formality. Getting a mere signature on a form is no consent. If a patient is rushed into signing consent, without giving sufficient information, the consent may be invalid, despite the signature. Often medical professionals either ignore or are ignorant of the requirements of a valid consent and its legal implications. Instances where either consent was not taken or when an invalid consent was obtained have been a subject matter of judicial scrutiny in several medical malpractice cases. This article highlights the essential principles of consent and the Indian law related to it along with some citations, so that medical practitioners are not only able to safeguard themselves against litigations and unnecessary harassment but can act rightfully.

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.