Ahmed Hasanin

BACKGROUND: This study aimed to evaluate the accuracy of pulse oximetry-derived oxygen saturation (SpO) on room air, determined at hospital admission, as a predictor for the need for mechanical ventilatory support in patients with Coronavirus Disease-2019 (COVID-19).

METHODS: In this retrospective observational study, demographic and clinical details of the patients were obtained during ICU admission. SpO and respiratory rate (RR) on room air were determined within the first 6 h of hospital admission. As all measurements were obtained on room air, we calculated the simplified respiratory rate‑oxygenation (ROX) index by dividing the SpO by the RR. Based on the use of any assistance of mechanical ventilator (invasive or noninvasive), patients were divided into mechanical ventilation (MV) group and oxygen therapy group. The accuracy of the SpO, CT score, and ROX index to predict the need to MV were determined using the Area under receiver operating curve (AUC).

RESULTS: We included 72 critically ill patients who tested COVID-19-positive. SpO on the room air could predict any MV requirement (AUC [95% confidence interval]: 0.9 [0.8-0.96], sensitivity: 70%, specificity 100%, cut-off value ≤78%, P < 0.001). Within the MV group, the use of noninvasive ventilation (NIV) was successful in 37 (74%) patients, whereas 13 patients (26%) required endotracheal intubation. The cut-off ROX value for predicting early NIV failure was ≤1.4, with a sensitivity of 85%, a specificity of 86%, and an AUC of 0.86 (95% confidence interval of 0.73-0.94, P < 0.0001).

CONCLUSIONS: A baseline SpO ≤78% is an excellent predictor of MV requirement with a positive predictive value of 100%. Moreover, the ROX index measured within the first 6 h of hospital admission is a good indicator of early NIV failure.

BACKGROUND: Studies of the accuracy of different airway tests are lacking in elderly. We evaluated and compared the accuracy of thyromental height in predicting difficult intubation in relation to the other traditional airway tests in elderly.

METHODS: We included 120 patients aged ≥ 65 years scheduled for general anesthesia with tracheal intubation. Thyromental height, modified Mallampati test, thyromental distance and sternomental distance were evaluated. Cormack-Lehane grade > 2 was considered difficult laryngoscopy. Difficult tracheal intubation was considered if successful intubation required more than 2 attempts. The accuracy of different tests in predicting difficult intubation and difficult laryngoscopy were evaluated through area under receiver operating characteristic (AUROC) curves. Univariate and multivariate analyses were conducted to identify risk factors for difficult intubation and difficult laryngoscopy.

RESULTS: Our cohort had a mean age of 71(7) years. We encountered difficult laryngoscopy in 15/120 (12%) patients, difficult intubation in 20/120 (17%) patients, and failed laryngoscopy requiring alternative methods for securing the airway in 3/120 (3%) patients. For predicting difficult intubation, thyromental height and modified Mallampati test showed the highest accuracy AUROC (95% confidence interval): 0.9 (0.83-0.95), cut-off value ≤ 5.9 cm, and AUROC (95% confidence interval): 0.89 (0.82-0.94), cut-off value > 2, respectively. Low thyromental height and high modified Mallampati test were the only independent risk factors for difficult laryngoscopy and difficult intubation.

CONCLUSION: In elderly scheduled for elective procedure, both thyromental height and modified Mallampati tests showed good accuracy in predicting difficult intubation and difficult laryngoscopy, whilst thyromental distance and sternomental distance were poor predictors.

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.

In this study, we evaluated the accuracy of oscillometric noninvasive blood pressure (NIBP) measured at the ankle in detecting low arm NIBP during cesarean delivery under spinal anesthesia. In this prospective observational study, a cohort of full-term mothers undergoing elective cesarean delivery under spinal anesthesia was examined. Simultaneous NIBP measurements were obtained from the arm and the ankle. The primary outcome was the accuracy of the ankle NIBP in detecting arm systolic blood pressure (SBP) < 90 mmHg. Other outcomes included the accuracy of ankle NIBP in detecting SBP < 80% of the baseline value. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the accuracy of ankle NIBP in detecting low arm NIBP. The Bland-Altman analysis was conducted to evaluate the agreement between values. We analyzed 1729 pairs of readings obtained from 97 mothers. Ankle SBP showed good accuracy in detecting SBP < 90 mmHg, with an AUC (95% confidence interval [CI]) of 0.90 (0.89-0.91) and a negative predictive value (NPV) of 99 (98-99%) at a cutoff value of ≤ 103 mmHg. Furthermore, ankle SBP showed good accuracy in detecting SBP < 80% of the baseline value, with an AUC (95% CI) of 0.84 (0.82-0.89) and an NPV of 95 (93-96%) at a cutoff value of ≤ 76% of the ankle baseline SBP. The mean bias between the two sites of measurement was - 5.4 ± 15.5, - 2.0 ± 11, and 0.5 ± 12.1 mmHg for SBP, diastolic blood pressure, and mean arterial pressure, respectively. In conclusion, ankle NIBP measurement is not interchangeable with arm NIBP measurement. However, ankle NIBP measurement showed good accuracy for ruling out low arm NIBP during a cesarean delivery.Clinical trial rejistration: NCT04199156.

Background: We aimed to evaluate the ability of inferior vena cava (IVC) distensibility using the transhepatic approach to predict fluid responsiveness in mechanically ventilated patients with septic shock after emergency laparotomy. Methods: This prospective observational study included mechanically ventilated paralyzed adult who had septic shock after emergency laparotomy. The IVC dimensions were measured through the transhepatic and subxiphoid approaches. The fluid responsiveness was confirmed with >15% increase in cardiac output after 500 mL of fluid bolus. The outcomes were the ability of transhepatic (primary outcome) and subxiphoid approach to predict fluid responders using the area under the receiver operating characteristics curve analysis. The gray zone for the two approaches was calculated. Results: Data from 51 patients were analyzed, and the number of fluid responders was 30 of 52 (58%). The transhepatic approach was feasible in all patients, whereas the subxiphoid approach was only feasible in 42 patients. The area under the receiver operating characteristics curve (95% confidence interval) for the transhepatic IVC distensibility was 0.88 (0.76-0.95), and it was comparable with that of the subxiphoid approach (0.81 [0.66-0.92], P = 0.417). The gray zone for the transhepatic IVC distensibility was 17% to 35% including 24 of 51 patients (47%), whereas the gray zone for the subxiphoid IVC distensibility was 13% to 34% including 18 of 42 patients (43%). Conclusion: In conclusion, the transhepatic approach for evaluation of IVC distensibility showed good accuracy in predicting fluid responsiveness in patients with septic shock after emergency laparotomy. The transhepatic approach showed the same accuracy as the subxiphoid approach with the advantage of being feasible in larger number of 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.

The evolution of non-invasive hemoglobin measuring technology would save time and improve transfusion practice. The validity of pulse co-oximetry hemoglobin (SpHb) measurement in the perioperative setting was previously evaluated; however, the accuracy of SpHb in different volume statuses as well as in different perfusion states was not well investigated. The aim of this work is to evaluate the accuracy and trending of SpHb in comparison to laboratory hemoglobin (Lab-Hb) during acute bleeding and after resuscitation. Seventy patients scheduled for major orthopedic procedures with anticipated major blood loss were included. Radical-7 device was used for continuous assessment of SpHb, volume status [via pleth variability index (PVI)] and perfusion status [via perfusion index (PI)]. Lab-Hb and SpHb were measured at three time-points, a baseline reading, after major bleeding, and after resuscitation. Samples were divided into fluid-responsive and fluid non-responsive samples, and were also divided into high-PI and low-PI samples. Accuracy of SpHb was determined using Bland-Altman analysis. Trending of SpHb was evaluated using polar plot analysis. We obtained 210 time-matched readings. Fluid non-responsive samples were 106 (50.5%) whereas fluid responsive samples were 104 (49.5%). Excellent correlation was reported between Lab-Hb and SpHb (r = 0.938). Excellent accuracy with moderate levels of agreement was also reported between both measures among all samples, fluid non-responsive samples, fluid-responsive samples, high-PI samples, and low-PI samples [Mean bias (limits of agreement): 0.01 (- 1.33 and 1.34) g/dL, - 0.08 (- 1.27 and 1.11) g/dL, 0.09 (- 1.36 and 1.54) g/dL, 0.01 (- 1.34 to 1.31) g/dL, and 0.04 (- 1.31 to 1.39) g/dL respectively]. Polar plot analysis showed good trending ability for SpHb as a follow up monitor. In conclusion, SpHb showed excellent correlation with Lab-Hb in fluid responders, fluid non-responders, low-PI, and high PI states. Despite a favorable mean bias of 0.01 g/dL for SpHb, the relatively wide levels of agreement (- 1.3 to 1.3 g/dL) might limit its accuracy. SpHb showed good performance as a trend monitor.

BACKGROUND: Fluid challenge test is a widely used method for the detection of fluid responsiveness in acute circulatory failure. However, detection of the patient's response to the fluid challenge requires monitoring of cardiac output which is not feasible in many settings. We investigated whether the changes in the pulse oximetry-derived peripheral perfusion index (PPI), as a non-invasive surrogate of cardiac output, can detect fluid responsiveness using the fluid challenge test or not.

METHODS: We prospectively enrolled 58 patients with septic shock on norepinephrine infusion. Fluid challenge test, using 200 mL crystalloid solution, was performed in all study subjects. All patients received an additional 300 mL crystalloid infusion to confirm fluid responsiveness. Velocity time integral (VTI) (using transthoracic echocardiography), and PPI were measured at the baseline, after 200 mL fluid challenge, and after completion of 500 mL crystalloids. Fluid responsiveness was defined by 10% increase in the VTI after completion of the 500 mL. The predictive ability of ∆PPI [Calculated as (PPI after 200 mL - baseline PPI)/baseline PPI] to detect fluid responders was obtained using the receiver operating characteristic curve.

RESULTS: Forty-two patients (74%) were fluid responders; in whom, the mean arterial pressure, the central venous pressure, the VTI, and the PPI increased after fluid administration compared to the baseline values. ∆PPI showed moderate ability to detect fluid responders [area under receiver operating characteristic curve (95% confidence interval) 0.82 (0.70-0.91), sensitivity 76%, specificity 80%, positive predictive value 92%, negative predictive value 54%, cutoff value ≥ 5%]. There was a significant correlation between ∆PPI and ∆VTI induced by the fluid challenge.

CONCLUSION: ∆PPI showed moderate ability to detect fluid responsiveness in patients with septic shock on norepinephrine infusion. Increased PPI after 200 mL crystalloid challenge can detect fluid responsiveness with a positive predictive value of 92%; however, failure of the PPI to increase does not exclude fluid responsiveness.

CLINICAL TRIAL IDENTIFIER: NCT03805321. Date of registration: 15 January 2019. Clinical trial registration URL: https://clinicaltrials.gov/ct2/show/NCT03805321?term=ahmed+hasanin&amp;rank=9 .

Supraclavicular nerve block (SCB) is a commonly used regional block for upper extremity surgery. The most common form of failure of SCB is ulnar segmental sparing. We aimed to evaluate the accuracy of perfusion index (PI) in early detection of segmental sparing of the ulnar component of SCB. A prospective observational study included adult patients scheduled for surgery under ultrasound-guided SCB. PI was simultaneously measured at the index finger and little finger. PI was recorded every minute for the first 10 min after SCB. PI ratio was calculated at every measurement point as PI/baseline PI. The area under the receiver operating characteristic (AUROC) curve was calculated for the ability of PI ratio to detect segmental ulnar sparing with comparison of little finger readings to the index finger readings. Forty-nine patients were available for the final analysis. Nine patients (18%) had segmental ulnar sparing. PI ratio at the little finger showed excellent predictive ability for ulnar sparing starting from the fifth minute (AUROC 0.92 [0.8-0.98], cutoff value ≤ 1.71) and reached the highest value at the seventh minute (AUROC 0.96 [0.86-1], cutoff value ≤ 1.35), whereas PI ratio at the index finger showed poor predictive ability. When using the PI for evaluation of successful SCB, segmental ulnar sparing could be accurately detected when the PI was measured at the little finger and not at the index finger. An increase of 71% in PI at the little finger 5 min after SCB could accurately rule out ulnar sparing.Clinical trial identifier NCT03880201. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT03880201?term=NCT03880201&amp;draw=2&amp;rank=1 .

In this study we aimed to evaluate the ability of IMPROVE and IMPROVE-DD scores in predicting in-hospital mortality in patients with severe COVID-19. This prospective observational study included adult patients with severe COVID-19 within 12 h from admission. We recorded patients' demographic and laboratory data, Charlson comorbidity index (CCI), SpO at room air, acute physiology and chronic health evaluation II (APACHE II), IMPROVE score and IMPROVE-DD score. In-hospital mortality and incidence of clinical worsening (the need for invasive mechanical ventilation, vasopressors, renal replacement therapy) were recorded. Our outcomes included the ability of the IMPROVE and IMPROVE-DD to predict in-hospital mortality and clinical worsening using the area under receiver operating characteristic curve (AUC) analysis. Multivariate analysis was used to detect independent risk factors for the study outcomes. Eighty-nine patients were available for the final analysis. The IMPROVE and IMPROVE-DD score showed the highest ability for predicting in-hospital mortality (AUC [95% confidence intervals {CI}] 0.96 [0.90-0.99] and 0.96 [0.90-0.99], respectively) in comparison to other risk stratification tools (APACHE II, CCI, SpO). The AUC (95% CI) for IMPROVE and IMPROVE-DD to predict clinical worsening were 0.80 (0.70-0.88) and 0.79 (0.69-0.87), respectively. Using multivariate analysis, IMPROVE-DD and SpO were the only predictors for in-hospital mortality and clinical worsening. In patients with severe COVID-19, high IMPROVE and IMOROVE-DD scores showed excellent ability to predict in-hospital mortality and clinical worsening. Independent risk factors for in-hospital mortality and clinical worsening were IMPROVE-DD and SpO.