Background and Aims:Changes in end-tidal carbon dioxide (ΔETCO2) have been proposed as a predictor of fluid responsiveness, but the available evidence remains inconsistent. We evaluated the ability of ΔETCO2 to predict a ≥10% increase in cardiac index (ΔCI) following administration of a 4 mL/kg crystalloid bolus in patients undergoing major abdominal surgery. Methods:We conducted a prospective study in 22 adults undergoing major abdominal surgery between April 2022 and January 2023. Cardiac output and stroke volume were monitored using the FloTrac™ system with a Vigileo or EV1000 monitor. Patients were mechanically ventilated with a tidal volume of 8 mL/kg predicted body weight and a respiratory rate of 12-16 breaths/min. An intravenous bolus of Ringer's lactate (4 mL/kg actual body weight over 10 minutes) was administered when haemodynamic parameters suggested hypovolaemia. Patients with a ΔCI ≥10% were classified as fluid responders, with ΔCI serving as the reference standard. ΔETCO2 was evaluated against changes in stroke volume index (ΔSVI) and compared with pulse pressure variation (PPV) and stroke volume variation (SVV). Diagnostic performance was assessed using the area under the receiver operating characteristic (AUROC) curve. Results:ΔETCO2 moderately predicted fluid responsiveness, with an AUROC of 0.823 [95% confidence interval (CI): 0.688-0.955] at a threshold of 1.5 mmHg (Youden index: 0.588, P < 0.001). It outperformed pre-bolus PPV and SVV, which had AUROC values of 0.563 (95% CI: 0.344-0.782; threshold 16.5%; Youden index: 0.242; P = 0.554) and 0.427 (95% CI: 0.209-0.644; threshold 12.5%; Youden index: 0.050; P = 0.508), respectively. Conclusion:ΔETCO2 may be a useful marker of fluid responsiveness after a fluid challenge.
Background and Aims:Laryngoscopy and endotracheal intubation are associated with a sympathetic response which is detrimental in hypertensive patients. Blocking afferent laryngeal reflexes with the internal branch of the superior laryngeal nerve block (iSLNB) may attenuate this response. This study aimed to evaluate the effectiveness of ultrasound-guided bilateral iSLNB as an adjunct to general anaesthesia (GA) in blunting the haemodynamic response to intubation in patients with hypertension. Methods:This prospective, randomised, single-blind clinical trial enroled adult patients with hypertension undergoing elective non-airway surgery under GA with tracheal intubation. Participants were randomly allocated to two groups. The iSLNB group received ultrasound-guided bilateral iSLNB using lignocaine following intravenous induction, while the control group received standard intravenous induction. The primary outcome was change in mean blood pressure (∆MBP) from pre-intubation to one-minute post-intubation. Secondary outcomes included change in systolic and diastolic blood pressure, heart rate at predefined intervals, incidence and severity of postoperative sore throat, and procedure-related adverse events. Results:A total of 50 patients were analysed, 25 in each group. The change in post-intubation MBP at one minute was significantly lower in the iSLNB group compared to the control group (mean difference 6.2 mm Hg; 95% confidence interval 0.73-11.67; P = 0.03), while changes in heart rate were comparable during the study period. The postoperative sore throat was significantly lower in the iSLNB group (P = 0.01), and no block-related adverse events were observed. Conclusion:Ultrasound-guided iSLNB as an adjunct to GA effectively attenuates the haemodynamic response to endotracheal intubation.
Background and Aims:Ultrasonographic skin-to-epiglottis depth (SED) has been proposed as a predictor of difficult laryngoscopy (DL). Most studies have evaluated transverse measurements at a single anatomical level, and the influence of parasagittal imaging and measurement level on diagnostic performance remains unclear. This study aimed to assess anatomical level-dependent variation in parasagittal SED and to compare its diagnostic accuracy for predicting DL. Methods:In this prospective observational study, 150 adult patients undergoing elective surgery under general anaesthesia were evaluated preoperatively. Parasagittal SED was measured at three anatomical landmarks: the upper hyoid border (HUB), lower hyoid border (HLB), and thyrohyoid membrane (THM). Difficult laryngoscopy was defined as Cormack-Lehane grade III-IV. Diagnostic performance was analysed using receiver operating characteristic analysis. Results:DL occurred in 32 patients (21.3%). Parasagittal SED differed significantly across anatomical levels. HUB measurements demonstrated superior predictive performance [area under the curve (AUC) 0.86; 95% confidence interval 0.79-0.92] compared with HLB (AUC 0.75) and THM (AUC 0.65). The HUB/THM ratio showed similarly high discrimination (AUC 0.86). Conventional airway tests showed modest predictive values (AUC 0.62-0.72). Multivariable analysis identified HUB SED >24 mm, inter-incisor distance ≤4 cm, and upper lip bite test class II-III as independent predictors of DL. Conclusion:Parasagittal SED demonstrates anatomical level-dependent variability that affects diagnostic performance. Assessment at the upper hyoid border provides the highest discrimination and may improve ultrasound-based airway risk stratification.
Background and Aims:Tracheal extubation is a vulnerable phase of general anaesthesia. Smooth extubation strategies aim to reduce cough, bucking, and the sympathetic surge. This trial compared deep extubation with no-touch awake extubation in adults undergoing elective laparotomy. Methods:This prospective, randomised, partially outcome-assessor-blinded trial enroled American Society of Anesthesiologists (ASA) physical status I-II adults scheduled for elective laparotomy, allocated to deep extubation (Group D) or no-touch awake extubation (Group N). The primary outcome was cough (grade ≥1) within five minutes of extubation. Secondary outcomes were cough severity, airway adverse events, airway support, haemodynamics, and recovery characteristics. Results:Seventy patients (35 per group) were analysed. Cough occurred in 3 (8.6%) patients in Group D and 8 (22.9%) in Group N (P = 0.18). Deep extubation was associated with more desaturation below 95% (11 vs 2; P = 0.009), more breath-holding (8 vs 1; P = 0.028), greater need for airway support, and four re-intubations versus none. Recovery times were shorter in Group D. The heart rate and blood pressure were higher in Group N during early recovery. Conclusion:Deep extubation did not significantly reduce cough and was associated with more airway-related adverse events and airway support needs, including reintubation. Shorter recovery times and less moderate-to-severe cough in Group D did not reduce these risks. The findings do not support routine use of deep extubation and need confirmation in a larger, adequately powered trial.
