A performance comparison of the most commonly used minimally invasive monitors of cardiac output.

BACKGROUND: Shock is common in critically ill and injured patients. Survival during shock is highly dependent on rapid restoration of tissue oxygenation with therapeutic goals based on cardiac output (CO) optimization. Despite the clinical availability of numerous minimally invasive monitors of CO, limited supporting performance data are available. METHODS: Following approval of the University of Saskatchewan Animal Research Ethics Board, we assessed the performance and trending ability of PiCCOplus™, FloTrac™, and CardioQ-ODM™ across a range of CO states in pigs. In addition, we assessed the ability of invasive mean arterial blood pressure (iMAP) to follow changes in CO using a periaortic transit-time flow probe as the reference method. Statistical analysis was performed with function-fail, bias and precision, percent error, and linear regression at all flow, low-flow (> 1 standard deviation [SD] below the mean), and high-flow (> 1 SD above the mean) CO conditions. RESULTS: We made a total of 116,957 paired CO measurements. The non-invasive CO monitors often failed to provide a CO value (CardioQ-ODM: 40.6% failed measurements; 99% confidence interval [CI], 38.5 to 42.6; FloTrac: 9.6% failed measurements; 99% CI, 8.7 to 10.5; PiCCOplus: 4.7% failed measurements; 99% CI, 4.5 to 4.9; all comparisons, P < 0.001). The invasive mean arterial pressure provided zero failures, failing less often than any of the tested CO monitors (all comparisons, P < 0.001). The PiCCOplus was most interchangeable with the flow probe at all flow states: PiCCOplus (20% error; 99% CI, 19 to 22), CardioQ-ODM (25% error; 99% CI, 23 to 27), FloTrac (34% error; 99% CI, 32 to 38) (all comparisons, P < 0.001). At low-flow states, CardioQ-ODM (43% error; 99% CI, 32 to 63) and Flotrac (45% error; 99% CI, 33 to 70) had similar interchangeability (P = 0.07), both superior to PiCCOplus (48% error; 99% CI, 42 to 60) (P < 0.001). Regarding CO trending, the CardioQ-ODM (correlation coefficient, 0.82; 99% CI, 0.81 to 0.83) was statistically superior to other monitors including iMAP, but at low flows iMAP (correlation coefficient, 0.58; 99% CI, 0.58 to 0.60) was superior to all minimally invasive CO monitors (all comparisons P < 0.001). CONCLUSIONS: None of the minimally invasive monitors of CO performed well at all tested flows. Invasive mean arterial blood pressure most closely tracked CO change at critical flow states.

RéSUMé: CONTEXTE: L'état de choc est fréquent chez les patients blessés et en urgence absolue. La survie pendant le choc dépend fortement de la restauration rapide de l'oxygénation tissulaire avec des objectifs thérapeutiques basés sur l'optimisation du débit cardiaque (DC). Malgré la disponibilité clinique de nombreux moniteurs minimalement invasifs du DC, il n'existe que des données limitées sur leur performance pour appuyer leur utilisation. MéTHODE: À la suite de l'approbation du comité d'éthique de la recherche animale de l'Université de la Saskatchewan, nous avons évalué la performance et la capacité de suivi des tendances des appareils PiCCOplus™, FloTrac™ et CardioQ-ODM™ sur une vaste gamme d'état de DC chez des cochons. Nous avons également évalué la capacité de la tension artérielle moyenne invasive (iMAP) à suivre les changements de DC en utilisant une sonde périaortique de débit basée sur le temps de transit comme méthode de référence. L'analyse statistique a été réalisée avec fonction-échec, biais et précision, pourcentage d'erreur et régression linéaire à des conditions de DC de tous les débits, de faible débit (> 1 écart-type [ET] au-dessous de la moyenne) et de débit élevé (> 1 ET au-dessus de la moyenne). RéSULTATS: Nous avons effectué un total de 116 957 mesures de DC appariées. Les moniteurs non invasifs de la DC n'ont souvent pas réussi à fournir une valeur de DC (CardioQ-ODM : 40,6% de mesures échouées; intervalle de confiance [IC] de 99 %, 38,5 à 42,6; FloTrac : 9,6 % de mesures échouées; IC 99 %, 8,7 à 10,5; PiCCOplus : 4,7 % de mesures échouées; IC 99 %, 4,5 à 4,9; toutes les comparaisons, P < 0,001). La tension artérielle moyenne invasive n'a fourni aucun échec plus souvent que n'importe lequel des moniteurs de DC testés (toutes les comparaisons, P < 0,001). Le PiCCOplus était le plus interchangeable avec la sonde de débit à tous les états de débit : PiCCOplus (erreur de 20 %; IC 99 %, 19 à 22), CardioQ-ODM (erreur de 25 %; IC 99 %, 23 à 27), FloTrac (erreur de 34 %; IC 99 %, 32 à 38) (toutes les comparaisons, P < 0,001). Aux états de débit faible, les moniteurs CardioQ-ODM (erreur de 43 %; IC 99 %, 32 à 63) et FloTrac (erreur de 45 %; IC 99 %, 33 à 70) présentaient une interchangeabilité similaire (P = 0,07), tous deux supérieurs au PiCCOplus (erreur de 48 %; IC 99 %, 42 à 60) (P < 0,001). En ce qui concerne le suivi des tendances de DC, le CardioQ-ODM (coefficient de corrélation, 0,82; IC 99 %, 0,81 à 0,83) était statistiquement supérieur aux autres moniteurs, y compris au iMAP, mais à faibles débits, l'iMAP (coefficient de corrélation, 0,58; IC 99 %, 0,58 à 0,60) était supérieure à tous les moniteurs de DC minimalement invasifs (toutes les comparaisons, P < 0,001). CONCLUSION: Aucun des moniteurs de DC minimalement invasif n'a donné de bons résultats à tous les débits testés. La tension artérielle moyenne invasive était le moniteur qui a suivi de plus près les changements de DC dans des états critiques de débit.

A comparison of methods used to secure pediatric endotracheal tubes using a live human dermal model.

BACKGROUND: Endotracheal intubation is a common lifesaving procedure. An in situ endotracheal tube (ETT) must be secured in position to avoid displacement and potentially life-threatening complications. Adhesive tapes form the most common intraoperative ETT stabilization methods. Limited published data are available to guide the clinical decision regarding ETT taping method. We performed an interventional study aiming to establish which of many commonly employed ETT tape/supplementary adhesive methods provides the most resistance to ETT distraction. METHODS: An experiment was undertaken to measure the force required to distract an ETT secured to a live dermal model with 24 different ETT securing methods comprising six types of tape alone and in combination with one of three supplementary adhesives. The primary measurement was the peak force (Newtons) required to distract a secured ETT 3 cm. RESULTS: A total of 1,164 measurements were made. The mean force required to distract the ETT ranged from 7.8 to 21.8 Newtons. The combination of Cloth Adhesive™ + Mastisol® had the greatest observed mean distraction force, as well as the greatest estimated lower and upper confidence limits. CONCLUSIONS: There are significant differences in force required to distract an ETT based on taping methods.

RéSUMé: CONTEXTE: L'intubation endotrachéale est une intervention critique courante. Le tube endotrachéal (TET) in situ doit être fixé en position adéquate pour éviter qu'il ne se déplace et provoque des complications potentiellement fatales. Les bandes adhésives sont la méthode de stabilisation peropératoire de TET la plus fréquemment utilisée. Il n'existe que peu de données publiées pour guider la décision clinique quant à la méthode de fixation du TET. Nous avons réalisé une étude interventionnelle visant à établir laquelle des nombreuses méthodes couramment employées de bandes adhésives ou de méthodes adhésives supplémentaires du TET procurait la meilleure protection contre un déplacement du TET. MéTHODE: Une expérience a été menée pour mesurer la force nécessaire à déplacer/déloger un TET fixée à un modèle de derme vivant avec 24 méthodes différentes de sécurisation du TET, comprenant six types de ruban adhésif seuls et en combinaison avec l'un de trois adhésifs supplémentaires. La mesure principale était la force maximale (en newton) nécessaire pour déplacer un TET sécurisée de 3 cm. RéSULTATS: Au total, 1164 mesures ont été effectuées. La force moyenne requise pour déplacer le TET allait de 7,8 à 21,8 newtons. La combinaison du ruban Cloth Adhesive™ + Mastisol® a entraîné la plus grande force de déplacement moyenne observée, ainsi que les plus grandes limites inférieure et supérieure estimées des intervalles de confiance. CONCLUSION: Il existe des différences significatives dans la force nécessaire pour déplacer un TET en fonction des méthodes de fixation utilisées.

Using automated pump-delivery devices to reduce the incidence of excessive fluid administration during pediatric dental surgery: a randomized-controlled trial.

PURPOSE: The harms caused by excessive perioperative intravenous (IV) fluid administration are both well recognized and avoidable. The purpose of this study was to compare the incidence of excess intraoperative fluid administration in pediatric dental surgery patients when either an automated pump-delivery device or a manual gravity-drip device is used. METHODS: We randomly assigned American Society of Anesthesiologists physical status I and II pediatric dental surgery patients to receive IV fluid via either a manual gravity-drip or automated pump-delivery device. Prior to each case, the attending anesthesiologist determined the target volume of maintenance IV fluid to be administered based on patient weight, estimated fluid deficits, and expected case length. The intraoperative IV fluid delivered was determined at the end of the case by the change in the IV bag weight. The primary outcome was the proportion of procedures that delivered ≥ 10% of the target IV fluid volume. RESULTS: We recruited 105 children aged two to 12 yr (n = 49 in the automated pump-delivery device; n = 53 in the manual gravity-drip device). The proportion of excessive fluid administration was 8/49 (16%) in the automated pump-delivery device group compared with 33/53 (62%) in the gravity-drip group (relative risk of excessive fluid administration, 0.26; 95% confidence interval, 0.13 to 0.51; P < 0.001). CONCLUSION: Intraoperative fluid administration using an automated pump-delivery device decreased the incidence of excessive IV fluid administration in pediatric dental surgery patients. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03312452); registered 17 October 2017.

RéSUMé: OBJECTIF: Les effets néfastes causés par une administration liquidienne intraveineuse (IV) périopératoire excessive sont à la fois bien connus et évitables. L'objectif de cette étude était de comparer l'incidence d'administration liquidienne peropératoire excessive chez les patients pédiatriques de chirurgie dentaire lors de l'utilisation d'une pompe à perfusion automatique vs un système goutte à goutte manuel par gravité. MéTHODE: Nous avons randomisé des patients pédiatriques de chirurgie dentaire de statut physique I et II selon l'American Society of Anesthesiologists à recevoir des liquides intraveineux soit par un système goutte à goutte manuel par gravité ou via une pompe à perfusion automatique. Avant chaque cas, l'anesthésiologiste en charge a déterminé le volume cible de liquide IV de maintien à administrer selon le poids du patient, les déficits liquidiens estimés, et la durée anticipée du cas. La quantité de liquides IV peropératoires administrés était déterminée à la fin du cas par le changement du poids du sac de liquide IV. Le critère d'évaluation principal était la proportion d'interventions ayant administré ≥ 10 % du volume liquidien IV cible. RéSULTATS: Nous avons recruté 105 enfants âgés de deux à 12 ans (n = 49 dans le groupe pompe automatique; n = 53 dans le groupe goutte à goutte manuel). La proportion d'administration liquidienne excessive était de 8/49 (16 %) dans le groupe pompe automatique, comparativement à 33/53 (62 %) dans le groupe goutte à goutte (risque relatif d'administration liquidienne excessive, 0,26; intervalle de confiance 95 %, 0,13 à 0,51; P < 0,001). CONCLUSION: L'administration liquidienne peropératoire à l'aide d'une pompe a réduit l'incidence d'administration liquidienne IV excessive chez des patients pédiatriques de chirurgie dentaire. ENREGISTREMENT DE L'éTUDE: ww.clinicaltrials.gov (NCT03312452); enregistrée le 17 octobre 2017.

Artificial ventilation during transport: A randomized crossover study of manual resuscitators with comparison to mechanical ventilators in a simulation model.

BACKGROUND: Positive-pressure ventilation in critically ill patients is commonly administered via a manual resuscitation device or a mechanical ventilator during transport. Our group previously compared delivered ventilation parameters between a self-inflating resuscitator and a flow-inflating resuscitator during simulated in-hospital pediatric transport. However, unequal group access to inline pressure manometry may have biased our results. In this study, we examined the performance of the self-inflating resuscitator and the flow-inflating resuscitator, both equipped with inline manometry, and several mechanical ventilators to deliver prescribed ventilation parameters during simulated pediatric transport. METHODS: Thirty anesthesia providers were randomized to initial resuscitator device used to hand ventilate a test lung. The resuscitators studied were a Jackson-Rees circuit (flow-inflating resuscitator) or a Laerdal pediatric silicone resuscitator (self-inflating resuscitator), both employing manometers. The scenario was repeated using several mechanical transport ventilators (Hamilton-T1, LTV® 1000, and LTV® 1200). The primary outcome was the proportion of total breaths delivered within the predefined target PIP/PEEP range (30 ± 3, 10 ± 3 cm H2 O). RESULTS: The Hamilton-T1 outperformed the other ventilators for breaths in the recommended range (χ2  = 2284, df = 2, P < .001) and with no breaths in the unacceptable range (χ2  = 2333, df = 2, P < .001). Hamilton-T1 also outperformed all human providers in proportion of delivered acceptable and unacceptable breaths (χ2  = 4540, df = 3, P < .001 and χ2  = 639, df = 3, P < .001, respectively). Compared with the flow-inflating resuscitator, the self-inflating resuscitator was associated with greater odds of breaths falling outside the recommended range (Odds ratio (95% CI): 1.81 (1.51-2.17)) or unacceptable (Odds ratio (95% CI): 1.63 (1.48-1.81)). CONCLUSION: This study demonstrates that a majority of breaths delivered by manual resuscitation device fall outside of target range regardless of provider experience or device type. The mechanical ventilator (Hamilton-T1) outperforms the other positive-pressure ventilation methods with respect to delivery of important ventilation parameters. In contrast, 100% of breaths delivered by the LTV 1200 were deemed unacceptable.

Ketamine-based anesthesia improves electroconvulsive therapy outcomes: a randomized-controlled study.

BACKGROUND: Major depressive disorder (MDD) is a common and debilitating condition that can be challenging to treat. Electroconvulsive therapy (ECT) is currently the therapeutic gold standard for treatment-resistant MDD. We tested our hypothesis that ketamine-based anesthesia for ECT results in superior improvement in treatment-resistant MDD outcomes compared with propofol-based anesthesia. METHODS: Patients with treatment-resistant MDD were enrolled in a randomized clinical trial with assignment to ketamine- or propofol-based anesthesia arms. Using a modified intention-to-treat analysis, we compared the median number of ECT treatments required to achieve a 50% reduction (primary outcome) and a score ≤ 10 (secondary outcome) on the Montgomery-Asberg depression rating scale (MADRS) between anesthesia groups. RESULTS: The study was terminated as significant results were found after the first planned interim analysis with 12 patients in each of the ketamine (intervention) and propofol (control) groups. All ketamine patients achieved at least a 50% MADRS reduction after a median of two ECT treatments whereas ten propofol patients (83%) achieved the same outcome after a median of four ECT treatments. All ketamine patients and seven propofol patients (58%) achieved MDD remission (MADRS ≤ 10). Log rank tests showed that both time-to-50% reduction and remission differed significantly between groups. Adverse events and recovery time were similar between groups. CONCLUSIONS: In this early-terminated small-sized study, ketamine-based anesthesia compared with propofol-based anesthesia provided response and remission after fewer ECT sessions. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT01935115). Registered 4 September 2013.

Tension pneumothorax during flexible bronchoscopy in a nonintubated infant.

We describe the case of a tension pneumothorax occurring during flexible bronchoscopy in a nonintubated infant. The pneumothorax likely occurred secondary to wall source oxygen insufflation via the bronchoscope without sufficient gas egress. The use of wall source oxygen via the bronchoscope working channel is inherently dangerous and should be avoided.

Three-finger tracheal palpation to guide endotracheal tube depth in children.

BACKGROUND: Accurate endotracheal tube (ETT) depth is critical, especially in children. The current tools used to guide appropriate ETT depth have significant limitations. OBJECTIVES: To evaluate the utility of tracheal palpation in the neck to guide appropriate ETT placement in children. METHODS: A prospective observational study with a convenience sample of 50 children was conducted. During intubation, an investigator palpated the trachea with three fingertips side-by-side extending upward from the suprasternal notch. The anesthesiologist advanced the ETT slowly until palpated at the sternal notch. The investigator stated ETT palpation certainty as 'strongly felt', 'weakly felt', or 'not felt.' Final ETT position was determined by bronchoscopy and categorized as 'ETT too shallow' (tip in proximal » of trachea), 'ETT too deep' (tip in distal » of trachea), or 'ETT placement satisfactory' (between those extremes). RESULTS: Thirty boys and 20 girls undergoing dental surgery with nasal intubation were recruited (median age 4.4 years; range 2.0-10.8). The ETT (all ≥4 mm ID) was palpable at the sternal notch in all patients: 46 of 50 strongly palpable and 4 of 50 weakly palpable. The experimental methods led to satisfactory ETT placement in 49 of 50 patients, too deep in 1 of 50 patients. Compared with the Pediatrics Advanced Life Support (PALS) predictive formula, satisfactory placement would have been 41 of 50 patients (P < 0.008). Number needed to treat is 6.3 for improvement over the PALS method. CONCLUSIONS: The use of tracheal palpation to guide ETT placement has excellent clinical performance and better guides appropriate ETT depth than the PALS formula in our study population.

Positive-pressure ventilation during transport: a randomized crossover study of self-inflating and flow-inflating resuscitators in a simulation model.

BACKGROUND: Positive-pressure ventilation during transport of intubated patients is generally delivered via a hand-pressurized device. Of these devices, self-inflating resuscitators (SIR) and flow-inflating resuscitators (FIR) constitute the two major types used. Selection of a particular device for transport, however, remains largely an institutional practice. OBJECTIVE: To evaluate the hypothesis that transport ventilation goals of intubated pediatric patients are better achieved using an FIR compared to an SIR. METHODS: This randomized crossover simulation study compared the performance of SIR and FIR among anesthesia providers in a pediatric transport scenario. Subjects hand-ventilated a test lung while simultaneously maneuvering a stretcher bed to simulate patient transport. Hand ventilation was carried out using a Jackson-Rees circuit (FIR) and a Laerdal pediatric silicone resuscitator (SIR). The primary outcome was the proportion of total breaths delivered within the predefined target PIP/PEEP range (30+/- 3, 10+/- 3 cm H2O). Secondary outcomes included proportion of total breaths delivered with operationally defined unacceptable breath variables (PIP > 35 cm H2O or PEEP < 5 cm H2O). RESULTS: Overall, participants were four times more likely to deliver target breaths and one-third less likely to deliver unacceptable breaths using the FIR compared to the SIR. When comparing device performance, a 44% increase in the proportions of target breaths and a 40.4% decrease in unacceptable breaths using the FIR were observed (P < 0.0001 for both). CONCLUSIONS: Hand ventilation during patient transport is superior using the FIR compared to the SIR to achieve target ventilatory goals and avoid unacceptable ventilatory cycles.

Stimulating thoracic epidural placement via a lumbar approach causes significant spinal cord damage in a porcine model.

BACKGROUND: Continuous thoracic epidural analgesia is a valuable and common technique for analgesia but involves risk to the spinal cord. There is significant pediatric experience safely placing thoracic epidurals via a caudal approach. The use of a stimulating catheter offers the advantage of real-time confirmation of appropriate catheter placement. We hypothesize that the tip of a stimulating epidural catheter can be reliably advanced to the thoracic epidural space with lumbar insertion in a porcine model. METHODS: This prospective experimental porcine study evaluated the feasibility of placing the tip of a stimulating epidural catheter to a predefined thoracic epidural location after percutaneous lumbar epidural access in six live pigs. After the lumbar epidural space was accessed, a stimulating epidural catheter was advanced until the targeted thoracic myotome was stimulated. The final position of the catheter in relation to the targeted location was determined by fluoroscopy. All animals were euthanized at the end of the experiment, necropsy and spinal cord histology were then performed to assess the extent of spinal cord damage. RESULTS: In all animals the epidural catheter tip could be accurately advanced to the targeted thoracic myotome. Gross subdural bleeding occurred in three of the six animals and deep spinal damage was observed in two of the six animals. In one animal, the catheter was placed in the subarachnoid space. CONCLUSIONS: Accurate access to the thoracic epidural space is possible via a lumbar approach using a stimulating epidural catheter. Based on gross and histopathological examination, this technique resulted in frequent complications, including subdural hemorrhage, deep spinal cord damage, and subarachnoid catheter placement.