Accuracy of oscillometric noninvasive blood pressure at the ankle in the lateral position during general anesthesia.

BACKGROUND: This study aimed to evaluate the accuracy of ankle blood pressure measurements in relation to invasive blood pressure in the lateral position. METHODS: This prospective observational study included adult patients scheduled for elective non-cardiac surgery under general anesthesia in the lateral position. Paired radial artery invasive and ankle noninvasive blood pressure readings were recorded in the lateral position using GE Carescape B650 monitor. The primary outcome was the ability of ankle mean arterial pressure (MAP) to detect hypotension (MAP < 70 mmHg) using area under the receiver operating characteristic curve (AUC) analysis. The secondary outcomes were the ability of ankle systolic blood pressure (SBP) to detect hypertension (SBP > 140 mmHg) as well as bias (invasive measurement - noninvasive measurement), and agreement between the two methods using the Bland-Altman analysis. RESULTS: We analyzed 415 paired readings from 30 patients. The AUC (95% confidence interval [CI]) of ankle MAP for detecting hypotension was 0.88 (0.83-0.93). An ankle MAP of ≤ 86 mmHg had negative and positive predictive values (95% CI) of 99 (97-100)% and 21 (15-29)%, respectively, for detecting hypotension. The AUC (95% CI) of ankle SBP to detect hypertension was 0.83 (0.79-0.86) with negative and positive predictive values (95% CI) of 95 (92-97)% and 36 (26-46)%, respectively, at a cutoff value of > 144 mmHg. The mean bias between the two methods was - 12 ± 17, 3 ± 12, and - 1 ± 11 mmHg for the SBP, diastolic blood pressure, and MAP, respectively. CONCLUSION: In patients under general anesthesia in the lateral position, ankle blood pressure measurements are not interchangeable with the corresponding invasive measurements. However, an ankle MAP > 86 mmHg can exclude hypotension with 99% accuracy, and an ankle SBP < 144 mmHg can exclude hypertension with 95% accuracy.

The use of thermal imaging for evaluation of peripheral tissue perfusion in surgical patients with septic shock.

BACKGROUND: In this study, we aimed to evaluate the ability of central-to-peripheral temperature gradients using thermal imaging to predict in-hospital mortality in surgical patients with septic shock. METHODS: This prospective observational study included adult patients with septic shock admitted to the intensive care unit postoperatively. Serum lactate (in mmol/L), capillary refill time (CRT) (in seconds), toe (peripheral) and canthal (central) temperature by infrared thermography and the corresponding room temperature in (Celsius [°C]) were assessed at the time of admission, 6- and 12 h after admission. The canthal-toe and room-toe temperature gradients were calculated. According to their final outcomes, patients were divided into survivors and non-survivors. The ability of canthal-toe temperature gradient (primary outcome), room-toe temperature gradient, toe temperature, serum lactate and CRT, measured at the prespecified timepoints to predict in-hospital mortality was analyzed using the area under receiver operating characteristic curve (AUC). RESULTS: Fifty-six patients were included and were available for the final analysis and 41/56 (73%) patients died. The canthal-toe and room-toe temperature gradients did not show significant accuracy in predicting mortality at any timepoint. Only the toe temperature measurement at 12 h showed good ability in predicting in-hospital mortality with AUC (95% confidence interval) of 0.72 (0.58-0.84) and a negative predictive value of 70% at toe temperature of ≤ 25.5 °C. Both serum lactate and CRT showed good ability to predict in-hospital mortality at all timepoints with high positive predictive values (> 90%) at cut-off value of > 2.5-4.3 mmol/L for the serum lactate and > 3-4.2 s for the CRT. CONCLUSION: In post-operative emergency surgical patients with septic shock, high serum lactate and CRT can accurately predict in-hospital mortality and were superior to thermal imaging, especially in the positive predictive values. Toe temperature > 25.5 °C, measured using infrared thermal imaging can exclude in-hospital mortality with a negative predictive value of 70%.

Oral midodrine for prophylaxis against post-spinal anesthesia hypotension during hip arthroplasty in elderly population: a randomized controlled trial.

BACKGROUND: We aimed to evaluate the efficacy of midodrine as a prophylaxis against post-spinal hypotension in elderly patients undergoing hip arthroplasty. METHODS: This randomized controlled trial included elderly patients undergoing hip arthroplasty under spinal anesthesia. Ninety minutes before the procedure, patients were randomized to receive either 5-mg midodrine or placebo (metoclopramide). After spinal anesthesia, mean arterial pressure (MAP) and heart rate were monitored every 2 min for 20 min then every 5 min until the end of the procedure. Post-spinal hypotension (MAP < 80% baseline) was treated with 10 mg ephedrine. The primary outcome was intraoperative ephedrine consumption. Secondary outcomes were the incidence of post-spinal hypotension, bradycardia, and hypertension (MAP increased by > 20% of the baseline reading). RESULTS: We analyzed 29 patients in the midodrine group and 27 in the control group. The intraoperative ephedrine consumption was lower in the midodrine group than in the control group (median [quartiles]: 10 [0, 30] mg versus 30 [20, 43] mg, respectively, P-value: 0.002); and the incidence of intraoperative hypotension was lower in the midodrine group than that in the control group. The incidence of hypertension and bradycardia were comparable between the two groups. CONCLUSION: The use of 5 mg oral midodrine decreased the vasopressor requirements and incidence of hypotension after spinal anesthesia for hip surgery in elderly patients. CLINICAL TRIAL REGISTRATION: This study was registered on September 22, 2022 at clinicaltrials.gov registry, NCT05548985, URL: https://classic. CLINICALTRIALS: gov/ct2/show/NCT05548985 .

Thermal Imaging to Predict Failed Supraclavicular Brachial Plexus Block: A Prospective Observational Study.

Background: Successful brachial plexus blockade produces sympathetic blockade, resulting in increased skin temperature in the blocked segments. This study aimed to evaluate the accuracy of infrared thermography in predicting failed segmental supraclavicular brachial plexus block. Methods: This prospective observational study included adult patients undergoing upper-limb surgery under supraclavicular brachial plexus block. Sensation was evaluated at the dermatomal distribution of the ulnar, median, and radial nerves. Block failure was defined as absence of complete sensory loss 30 min after block completion. Skin temperature was evaluated by infrared thermography at the dermatomal supply of the ulnar, median, and radial nerves at baseline, 5, 10, 15, and 20 min after block completion. The temperature change from the baseline measurement was calculated for each time point. Outcomes were the ability of temperature change at each site to predict failed block of the corresponding nerve using area under receiver-operating characteristic curve (AUC) analysis. Results: Eighty patients were available for the final analysis. The AUC (95% confidence interval [CI]) for the ability of temperature change at 5 min to predict failed ulnar, median, and radial nerve block was 0.79 (0.68-0.87), 0.77 (0.67-0.86), and 0.79 (0.69-0.88). The AUC (95% CI) increased progressively and reached its maximum values at 15 min (ulnar nerve 0.98 [0.92-1.00], median nerve 0.97 [0.90-0.99], radial nerve 0.96 [0.89-0.99]) with negative predictive value of 100%. Conclusion: Infrared thermography of different skin segments provides an accurate tool for predicting failed supraclavicular brachial plexus block. Increased skin temperature at each segment can exclude block failure in the corresponding nerve with 100% accuracy.

Evaluation of the accuracy of oscillometric non-invasive blood pressure measurement at the ankle in children during general anesthesia.

This study aimed to evaluate the accuracy of oscillometric blood pressure measurement at the ankle in children using invasive blood pressure as reference standard. This prospective observational study included children undergoing noncardiac surgery. Paired radial invasive and ankle non-invasive blood pressure measurements were obtained. Delta blood pressure was calculated as the difference between two consecutive readings. The primary outcome was the mean bias and agreement between the two methods using the Bland-Altman analysis. The ISO standard was fulfilled if the mean bias between the two methods was ≤ 5 ± 8 mmHg. Other outcomes included the trending ability of ankle blood pressure using the four-quadrant plot and the accuracy of ankle measurement to detect hypotension using area under receiver operating characteristic curve (AUC) analysis. We analyzed 683 paired readings from 86 children. The mean bias between the two methods for systolic, diastolic, and mean blood pressure (SBP, DBP, MAP) was - 7.2 ± 10.7, 4.5 ± 12.8, and - 1.8 ± 8.2 mmHg, respectively. The concordance rate of ankle blood pressure was 72%, 71%, and 77% for delta SBP, DBP and MAP, respectively. The AUC (95% confidence interval) for ankle MAP ability to detect hypotension was 0.91 (0.89-0.93) with negative predictive value of 100% at cut-off value ≤ 70 mmHg, We concluded that in pediatric population undergoing noncardiac surgery, ankle blood pressure was not interchangeable with the corresponding invasive readings with the ankle MAP having the least bias compared to SBP and DBP. An ankle MAP > 70 mmHg can exclude hypotension with negative predictive value of 100%.

Comparison of the hemodynamic effects of opioid-based versus lidocaine-based induction of anesthesia with propofol in older adults: a randomized controlled trial.

BACKGROUND: The present study aims to compare the hemodynamic profile of lidocaine and fentanyl during propofol induction of general anesthesia. METHODS: This randomized controlled trial included patients aged above 60 years undergoing elective non-cardiac surgery. The included patients received either 1 mg/kg lidocaine (n = 50) or 1 mcg/kg fentanyl (n = 50) based on total body weight with propofol induction of anesthesia. Patient's hemodynamics were recorded every minute for the first 5 min then every 2 min until 15 min after induction of anesthesia. Hypotension (mean arterial pressure [MAP] <65 mmHg or >30% reduction from baseline) was treated by intravenous 4 mcg bolus of norepinephrine. Outcomes included norepinephrine requirements (primary), the incidence of postinduction hypotension, MAP, heart rate, intubation condition, and postoperative delirium via the cognitive assessment method. RESULTS: Forty-seven patients in the lidocaine group and 46 patients in the fentanyl group were analyzed. None in the lidocaine group experienced hypotension, while 28/46 (61%) of patients in the fentanyl group developed at least one episode of hypotension requiring a median (25th and 75th quartiles) norepinephrine dose of 4 (0,5) mcg, p-value <0.001 for both outcomes. The average MAP was lower in the fentanyl group than in the lidocaine group at all time points after anesthesia induction. The average heart rate was comparable between the two groups nearly at all time points after anesthesia induction. The overall intubation condition was comparable between the two groups. None of the included patients developed postoperative delirium. CONCLUSION: Lidocaine-based regimen for induction of anesthesia reduced the risk of postinduction hypotension in older patients compared to the fentanyl-based regimen.

Erector spinae plane block versus subcostal transversus abdominis plane block in patients undergoing open liver resection surgery: A randomized controlled trial.

BACKGROUND: The aim of this study was to compare the analgesic efficacy of erector spinae plane block (ESPB) in relation to subcostal transversus abdominis plane block (TAPB) in patients undergoing open liver resection surgery. METHODS: In this randomized controlled trial, we included adult patients undergoing open liver resection surgery. After induction of general anaesthesia, the included patients were randomized to receive either ESPB (n = 30) or subcostal TAPB (n = 30). Postoperative pain was assessed using the numeric rating scale (NRS) at rest and during cough. Intravenous morphine boluses were used for management of breakthrough pain intra- and postoperatively. The study's primary outcome was morphine consumption during the first 24 h postoperatively. Secondary outcomes included intraoperative morphine consumption, time to first postoperative morphine requirement, incidence of complications, and patient satisfaction. RESULTS: Sixty patients were included and were available for the final analysis in this study. The intra-and postoperative morphine consumption were less in the ESPB group than the subcostal TAPB group (median [quartiles] morphine dose: 0 [0-0] vs 2 [0-5] mg, p = 0.007 and 20 [15-20] vs 25 [20-30] mg, p = 0.006, respectively). The time to first morphine requirement was longer in the ESPB group (median [quartiles]: 6.5 [5.5-6.5] h) than the subcostal TAPB group (median [quartiles]: 4.3 [1.0-6.5] h), P = 0.013. Patients in the ESPB group had lower incidence of sedation and higher level of satisfaction than the subcostal TAPB group. CONCLUSION: In patients undergoing open liver resection surgery, ESPB provided superior analgesic properties than subcostal TAPB. CLINICAL TRIAL REGISTRATION: NCT05253079, Principal investigator: Maha Mostafa, Date of registration: February 23, 2022. URL: https://clinicaltrials.gov/ct2/show/NCT05253079.

Evaluation of adequacy of ventilation and gastric insufflation at three levels of inspiratory pressure for facemask ventilation during induction of anaesthesia: A randomised controlled trial.

BACKGROUND: In this study, we aimed to compare three inspiratory pressures during facemask ventilation in paralysed patients regarding the subsequent incidence of gastric insufflation and the adequacy of lung ventilation. METHODS: In this randomised controlled trial, we included adult patients undergoing elective surgery under general anaesthesia. The patients were randomly allocated to receive positive inspiratory pressure (PIP) of 10, 15, or 20 cmH2O during pressure-controlled mask ventilation. Antral cross-sectional area (CSA) was assessed by ultrasound at baseline before mask ventilation and after endotracheal intubation and gastric insufflation was defined as increased CSA after endotracheal intubation > 30% of the baseline measurement. The primary outcome was the incidence of gastric insufflation. Other outcomes included the tidal volume, and the incidence of adequate ventilation (tidal volume of 6-10 mL/kg predicted body weight). RESULTS: We analysed data from 36 patients in each group. The number of patients with gastric insufflation was the lowest in the PIP 10 group (0/36 [0%]) in comparison with PIP 15 (2/36 [19%] and PIP 20 36/36 [100%] groups (P-values of 0.019 and < 0.001, respectively). The probability of adequate ventilation at any time point was the highest in PIP 10, followed by PIP 15, and was the lowest in the PIP 20 group. CONCLUSION: An inspiratory pressure of 10 cmH2O in paralysed patients provided the least risk of gastric insufflation with adequate ventilation during induction of general anaesthesia compared to inspiratory pressure of 15- and 20 cmH2O.

Evaluation of super-obesity and super-super-obesity as risk factors for difficult intubation in patients undergoing bariatric surgery.

BACKGROUND: Super-obesity is a serious disorder which requires bariatric surgery. The association of super-obesity and difficult intubation was not adequately established. OBJECTIVES: To determine if super-obesity and super-super-obesity are associated with difficult intubation or not. SETTING: University Hospital. METHODS: A cohort of obese patients scheduled for bariatric surgery was prospectively recruited. Super-obesity and super-super-obesity were defined as body mass index ≥50 kg/m2 and 60 kg/m2, respectively. Intubation difficulty was assessed by 2 methods: (1) intubation difficulty scale; (2) number of intubation attempts. Risk factors for difficult intubation were recorded. Univariate and multivariate analysis for risk factors for difficult intubation and difficult mask ventilation were performed. RESULTS: A total of 658 patients were enrolled in the study including 205 (31%) super-obese and 52 (8%) super-super-obese patients. Ninety-nine (15%) patients required more than 1 intubation attempt, while 215 (33%) patients had intubation difficulty scale ≥5. Ninety-four (14.4%) patients had mask ventilation of moderate difficulty, while only 2 (.3%) patients needed 2-person ventilation. The independent risk factors for difficult intubation using the two stated definitions were STOP-Bang and Mallampati score values. The independent risk factors for mask ventilation of moderate difficulty were STOP-Bang score, Mallampati score, and limited neck extension. CONCLUSION: Within obese patients, neither super-obesity nor super-super-obesity was associated with difficult intubation or difficult mask ventilation. High STOP-Bang and Mallampati score are the independent factors for difficult intubation.

Accuracy of oscillometric blood pressure measurement at both arms in the lateral position.

PURPOSE: To evaluate the accuracy of noninvasive blood pressure (NIBP) measurement at the dependent- and nondependent arms in the lateral position, using invasive blood pressure (IBP) as reference. METHODS: This prospective observational study included 42 adult patients undergoing surgery in the lateral position. Paired readings of IBP and NIBP were obtained at either arm. The accuracy of both arms in detecting mean arterial pressure (MAP) <70 mmHg was evaluated using the area under the receiver operating characteristic curve (AUC). The agreement between the IBP and NIBP was evaluated using the Bland-Altman and error grid analyses. RESULTS: We analyzed 350 and 347 paired readings at the dependent- and nondependent arms. The AUC for detecting hypotension was comparable in both arms. The negative and positive predictive values (95% confidence interval) were 100% (99-100%) and 24% (14-34%), respectively for the dependent arm at cutoff value MAP ≤86 mmHg; and were 99% (96-100%) and 21% (13-30%), respectively for the nondependent arm at cutoff value MAP ≤75 mmHg. The mean bias for MAP was -6.0 ± 9.1 and 6.3 ± 10.1 mmHg; and for systolic blood pressure was 0.3 ± 11.6 and 13.2 ± 12.6 mmHg, in the dependent- and nondependent arm, respectively. Error grid analysis showed that the proportions of paired MAP readings in risk zone A were 71 and 82% in the dependent- and the nondependent arms, respectively. CONCLUSION: In the lateral position, the NIBP readings at both arms are not interchangeable with the corresponding IBP readings. However, NIBP measurement at both arms can be used to accurately rule out hypotension.

Hemodynamic effects of norepinephrine versus phenylephrine infusion for prophylaxis against spinal anesthesia-induced hypotension in the elderly population undergoing hip fracture surgery: a randomized controlled trial.

BACKGROUND: Elderly population are at increased risk of spinal anesthesia-induced hypotension increasing their risk for postoperative morbidity and mortality. This study aimed to compare the hemodynamic effects of prophylactic infusion of norepinephrine (NE) versus phenylephrine (PE) in elderly patients undergoing hip fracture surgery under spinal anesthesia. METHODS: Elderly patients scheduled for hip fracture surgery were randomized to receive either NE infusion (8 µg/min) (NE group, n = 31) or PE infusion (100 µg/min) (PE group, n = 31) after spinal anesthesia. Outcomes included mean heart rate, mean blood pressure, cardiac output, incidence of spinal anesthesia-induced hypotension, incidence of bradycardia, and incidence of hypertension. RESULTS: Sixty-two patients with a mean age of 71 ± 6 years were included in the final analysis (31 patients in each group). The NE group showed a higher mean heart rate and cardiac output than the PE group. The NE group had a lower incidence of reactive bradycardia (10% vs. 36%, P = 0.031) and hypertension (3% vs. 36%, P = 0.003) than the PE group. No study participant developed hypotension, and the mean blood pressure was comparable between the two groups. CONCLUSIONS: Both NE and PE infusions effectively prevented spinal anesthesia-induced hypotension in elderly patients undergoing hip fracture surgery. However, NE provided more hemodynamic stability than PE; maintaining the heart rate, higher cardiac output, less reactive bradycardia, and hypertension.

The Use of Topical Nitroglycerin to Facilitate Radial Arterial Catheter Insertion in Children: A Randomized Controlled Trial.

OBJECTIVES: To determine whether the use of topical nitroglycerin patch increases radial artery diameter and facilitate cannulation in children. DESIGN: Randomized controlled trial. SETTING: Cairo University Hospital. PARTICIPANTS: Children aged 2 to 8 years old scheduled for cardiac surgery. INTERVENTION: In the nitroglycerin group (n = 20), a gauze-covered, half-sized nitroglycerin patch (5 mg) was applied at the site of radial pulsation 1 hour before induction of anesthesia. In the control group (n = 20), a gauze pad was applied to the bare skin at the site of radial pulsation with no intervention. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the diameter of the radial artery in both limbs using ultrasonography. Other outcomes included the degree of arterial palpability, number of arterial punctures, and incidence of successful first puncture cannulation. The radial artery diameter increased after 30 minutes and 60 minutes compared with the baseline value in the nitroglycerin group in both limbs, whereas no change was reported in the radial artery diameter in the control group. The nitroglycerin group showed a greater incidence of successful first cannulation trial, a fewer number of trials, and a shorter cannulation time compared with the control group. There were no significant hypotensive episodes in any patient. CONCLUSION: Local application of a half-sized, 5 mg nitroglycerin patch for 60 minutes in children increased the radial artery diameter bilaterally, increased the rate of first trial success, and decreased the time needed for arterial cannulation without significant hypotensive episodes.

Accuracy and trending of non-invasive oscillometric blood pressure monitoring at the wrist in obese patients.

BACKGROUND: In obese patients, non-invasive blood pressure monitoring in the arm is difficult due to the arm size and morphology. We compared the non-invasive oscillometric wrist blood pressure measurement with the arm and forearm in obese patients monitored with invasive radial blood pressure (reference standard). METHODS: This prospective observational study included adult obese patients scheduled for bariatric surgery. Non-invasive blood pressure was measured at the arm, upper forearm and wrist of one upper extremity, while invasive blood pressure was simultaneously measured through a radial arterial catheter in the contralateral upper extremity. The accuracy of non-invasive blood pressure reading at each site was evaluated for absolute and trending values using the Bland-Altman analysis and Spearman's correlation coefficient. RESULTS: In 40 patients, 262, 259, and 263 pairs of non-invasive blood pressure readings were obtained from the arm, forearm, and wrist sites, respectively. As primary outcome, the correlation coefficient for systolic blood pressure was higher for the wrist (0.92, 95% confidence interval (CI) [0.9-0.94]) than for the arm (0.74, 95% CI [0.68-0.79]) and the forearm (0.71, 95% CI [0.64-0.76]) (P<0.05). The non-invasive systolic wrist blood pressure showed the least mean bias and the narrowest limits of agreement (-0.3±7.6mmHg) when compared with forearm (4.3±16) and arm measurements (14.2±13.6) (P<0.05). For trending values, the correlation coefficient was the highest at the wrist. CONCLUSION: In obese patients undergoing bariatric surgery, non-invasive blood pressure measured at the wrist showed the highest accuracy in comparison with the arm and forearm.