OBJECTIVE: Hypotension after induction of general anesthesia is common and is associated with significant adverse events. Identification of patients at high risk can inform the use of preoperative mitigation strategies. We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of the inferior vena cava collapsibility index (IVC-CI) and maximal diameter (dIVCmax) in predicting postinduction hypotension and to identify their predictive performance across different threshold ranges.
METHODS: We searched MEDLINE, PubMed®, and Embase from inception to March 2023 for prospective observational studies exploring the performance of IVC-CI and dIVCmax in predicting postinduction hypotension in adults presenting for elective surgery under general anesthesia. We excluded studies reporting on IVC parameters predicting postinduction hypotension in the obstetric patient population or exclusively in patients with obesity. Trials screening and data extraction were conducted independently. We performed meta-analyses to identify the performance of IVC parameters in predicting postinduction hypotension, followed by subgroup analyses that sought the IVC-CI range with the highest hierarchical summary receiver-operating characteristic area under the curve (HSROC-AUC). We used a bivariate random effects model to calculate summary estimates. We evaluated study quality using Newcastle-Ottawa scores and certainty of evidence using the GRADE framework.
RESULTS: We included 14 studies involving 1,166 patients. Pooled sensitivity and specificity of the IVC-CI to predict postinduction hypotension was 0.68 (95% confidence interval [CI], 0.55 to 0.79; coverage probability, 0.91) and 0.78 (95% CI, 0.69 to 0.85; coverage probability, 0.9), respectively, with an HSROC-AUC of 0.80 (95% CI, 0.68 to 0.85, high quality of evidence). An IVC-CI threshold range of 40-45% had an HSROC-AUC of 0.86 (95% CI, 0.69 to 0.93, high quality of evidence).
CONCLUSIONS: Preoperative IVC-CI is a strong predictor of postinduction hypotension. We recommend that future studies use an IVC-CI threshold of 40-45% (low certainty of evidence). Future studies are needed to establish whether ultrasound-guided preoperative optimization improves outcomes in high-risk patients.
BACKGROUND: PROSPERO ( CRD42022316140 ); first submitted 10 March 2022.
RéSUMé: OBJECTIF: L’hypotension après l’induction de l’anesthésie générale est fréquente et est associée à des effets indésirables importants. L’identification des patient•es à haut risque peut éclairer l’utilisation de stratégies préopératoires d’atténuation. Nous avons réalisé une revue systématique et une méta-analyse pour évaluer la précision diagnostique de l’indice de collapsibilité de la veine cave inférieure (IC-VCI) et du diamètre maximal (dVCImax) pour prédire l’hypotension post-induction et identifier leurs performances prédictives dans différentes plages de seuils. MéTHODE: Nous avons fait des recherches dans les bases de données MEDLINE, PubMed® et Embase de leur création jusqu’en mars 2023 pour en extraire les études observationnelles prospectives explorant les performances de l’IC-VCI et du dVCImax pour la prédiction de l’hypotension post-induction chez des adultes se présentant pour une chirurgie non urgente sous anesthésie générale. Nous avons exclu les études rapportant des paramètres de VCI prédisant l’hypotension post-induction dans la population obstétricale ou exclusivement chez des personnes obèses. Le tri des études et l’extraction des données ont été menés indépendamment. Nous avons réalisé des méta-analyses pour identifier la performance des paramètres de VCI dans la prédiction de l’hypotension post-induction, suivies d’analyses de sous-groupes qui ont recherché la plage d’IC-VCI avec le plus haut niveau de hiérarchie de l’aire sous la courbe de la courbe ROC (HSROC-AUC). Nous avons utilisé un modèle bivarié à effets aléatoires pour calculer des estimations sommaires. Nous avons évalué la qualité des études à l’aide des scores de Newcastle-Ottawa et la certitude des données probantes à l’aide de l’outil GRADE. RéSULTATS: Quatorze études portant sur 1166 patient·es ont été incluses. La sensibilité et la spécificité combinées de l’IC-VCI pour prédire l’hypotension post-induction étaient de 0,68 (intervalle de confiance [IC] à 95 %, 0,55 à 0,79; probabilité de couverture, 0,91) et 0,78 (IC 95 %, 0,69 à 0,85; probabilité de couverture, 0,9), respectivement, avec une HSROC-AUC de 0,80 (IC 95 %, 0,68 à 0,85, données probantes de haute qualité). Une plage de seuils d’IC-VCI de 40 à 45 % avait une HSROC-AUC de 0,86 (IC 95 %, 0,69 à 0,93, haute qualité des données probantes). CONCLUSION: L’IC-VCI préopératoire est un bon prédicteur de l’hypotension post-induction. Nous recommandons que les études futures utilisent un seuil d’IC-VCI de 40 à 45 % (faible certitude des données probantes). De futures études sont nécessaires pour déterminer si l’optimisation préopératoire échoguidée améliore les devenirs chez la patientèle à risque élevé. ENREGISTREMENT DE L’éTUDE: PROSPERO ( CRD42022316140 ); première soumission le 10 mars 2022.

UNASSIGNED: Echocardiographic assessment of the inferior vena cava diameter (IVCD) and collapsibility index (IVCCI) is a noninvasive estimate of intravascular volume status (IVS) but requires validation for cirrhosis. We evaluated IVC dynamics in cirrhosis and correlated it with conventional tools such as central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), and right atrial pressure (RAP).
UNASSIGNED: A total of 673 consecutive cirrhotic patients were screened by echocardiography, and 125 patients underwent right heart catheterization with recording of hepatic venous pressure gradient (HVPG), RAP, pulmonary artery (PA) pressure, and PCWP. CVP data were available for 80 (64%) patients, and finally, 76 patients (84% male, 50% ethanol related, mean age 52.1 years, 57.8% with ascites) with complete data were enrolled.
UNASSIGNED: The mean CVP measured was 12.8 ± 4.8 mmHg, and IVCCI was 29.5 ± 10.9%. The IVCD ranged from 0.97 to 2.26 cm and from 0.76 to 1.84 cm during expiration and inspiration, respectively, with a mean of 1.8 ± 0.9 cm. The mean IVCD correlated with RAP (r = 0.633, P = 0.043) but not with HVPG (r = 0.344, P = 0.755), PCWP (r = 0.562, P = 0.072), or PA pressure (r = 0.563, P = 0.588). A negative linear correlation was observed between the CVP and the IVCCI (r = -0.827, P = 0.023) in all patients and substratified for those with (r = -0.748, P = 0.039) and without ascites (r = -0.761, P = 0.047). A positive correlation was observed between CVP and IVCDmax (r = 0.671, P = 0.037) and IVCDmin (r = 0.612, P = 0.040).
UNASSIGNED: IVCD and collapsibility index provides noninvasive IVS assessment, independent of HVPG or ascites, with the potential for calculating fluid requirements in cirrhosis.

Ultrasound (US) is considered the first step in evaluation of patients with shock; respiratory variation of the inferior vena cava (inferior vena cava collapsibility [IVCc]) is an important measurement in this scenario that can be impaired by patient condition or technical skills. The main objective of this study was to evaluate if respiratory variation of the femoral vein (femoral vein collapsibility [FVc]), which is easier to visualize, can adequately predict fluid responsiveness in septic shock patients. Forty-five mechanically ventilated septic shock patients in a mixed clinical-surgical, 30-bed intensive care unit were enrolled in this study. All patients underwent assessments of FVc, IVCc and cardiac output using a portable US device. The passive leg raising test was used to evaluate fluid responsiveness. FVc presented an area under the receiver operating characteristic curve of 0.678 (95% confidence interval: 0.519-0.837, p = 0.044) with a cutoff point of 17%, yielding a sensitivity of 62% and specificity of 65% in predicting fluid responsiveness. IVCc had greater diagnostic accuracy compared with FVc, with an area under the receiver operating characteristic curve of 0.733 (95% confidence interval: 0.563-0.903, p = 0.024) and a cutoff point of 29%, yielding a sensitivity of 47% and specificity of 86%. In conclusion, FVc has moderate accuracy when employed as an indicator of fluid responsiveness in spontaneously mechanically ventilated septic shock patients.

Measurement of inferior vena cava collapsibility (cIVC) by point-of-care ultrasound (POCUS) has been proposed as a viable, non-invasive means of assessing fluid responsiveness. We aimed to determine the ability of cIVC to identify patients who will respond to additional intravenous fluid (IVF) administration among spontaneously breathing critically-ill patients.
Prospective observational trial of spontaneously breathing critically-ill patients. cIVC was obtained 3cm caudal from the right atrium and IVC junction using POCUS. Fluid responsiveness was defined as a≥10% increase in cardiac index following a 500ml IVF bolus; measured using bioreactance (NICOM™, Cheetah Medical). cIVC was compared with fluid responsiveness and a cIVC optimal value was identified.
Of the 124 participants, 49% were fluid responders. cIVC was able to detect fluid responsiveness: AUC=0.84 [0.76, 0.91]. The optimum cutoff point for cIVC was identified as 25% (LR+ 4.56 [2.72, 7.66], LR- 0.16 [0.08, 0.31]). A cIVC of 25% produced a lower misclassification rate (16.1%) for determining fluid responsiveness than the previous suggested cutoff values of 40% (34.7%).
IVC collapsibility, as measured by POCUS, performs well in distinguishing fluid responders from non-responders, and may be used to guide IVF resuscitation among spontaneously breathing critically-ill patients.

BACKGROUND: Correcting hypovolemia is extremely important. Central venous pressure measurement is often done to assess volume status. Measurement of inferior vena cava (IVC) is conventionally done in the subcostal view using ultrasonography. It may not be possible to obtain this view in all patients.
OBJECTIVE: We therefore evaluated the limits of agreement between the IVC diameter measurement and variation in subcostal and that by the lateral transhepatic view.
METHODS: Prospective study in a tertiary care referral hospital intensive care unit.
METHODS: After Institutional Ethics Committee approval and informed consent, we obtained 175 paired measurements of the IVC diameter and variation in both the views in adult mechanically ventilated patients. The measurements were carried out by experienced researchers. We then obtained the limits of agreement for minimum, maximum diameter, percentage variation of IVC in relation to respiration.
METHODS: Bland-Altman\'s limits of agreement to get precision and bias.
RESULTS: The limits of agreement were wide for minimum and maximum IVC diameter with variation of as much as 4 mm in both directions. However, the limits of agreement were much narrower when the percentage variation in relation to respiration was plotted on the Bland-Altman plot.
CONCLUSIONS: We conclude that when it is not possible to obtain the subcostal view, it is possible to use the lateral transhepatic view. However, using the percentage variation in IVC size is likely to be more reliable than the absolute diameter alone. It is possible to use both views interchangeably.

OBJECTIVE: We sought to assess vascular structure and function in early- and late-onset preeclampsia (PE) at the time of diagnosis.
METHODS: We evaluated 100 PE cases subdivided into 50 early- and 50 late-onset cases according to gestational age at onset (34 weeks), and 100 controls paired by maternal age and gestational age at scan with cases. Carotid intima-media thickness (IMT), distensibility, and circumferential wall stress together with inferior vena cava (IVC) collapsibility were assessed by ultrasound.
RESULTS: Early PE was characterized by increased carotid IMT diameters, and arterial stiffness with no significant changes in IVC parameters as compared to normotensive pregnancies. Late PE was characterized by significantly increased carotid IMT and lumen diameters as compared to controls while arterial stiffness, as expressed by distensibility, did not provide pronounced changes. A significant decrease of IVC collapsibility index was also observed in late PE as compared to controls.
CONCLUSIONS: The current data suggest that distinct vascular adaptations in early and late PE could reflect different pathophysiologic mechanisms. Future studies are warranted to further assess the complex etiologies and clinical expressions of the 2 entities.