Comparison of carbetocin as a bolus or an infusion with prophylactic phenylephrine on maternal heart rate during Cesarean delivery under spinal anesthesia: a double-blinded randomized controlled trial.

PURPOSE: Carbetocin, an oxytocin analog, given as a postpartum hemorrhage prophylaxis in elective Cesarean deliveries, frequently causes tachycardia and hypotension. Phenylephrine infusion has been shown to prevent spinal anesthesia-induced hypotension. The goal of this study was to evaluate if a slow infusion of carbetocin would reduce maternal heart rate variation and hemodynamic disturbances compared with a rapid bolus in parturients receiving a prophylactic phenylephrine infusion during elective Cesarean delivery. METHODS: In this double-blinded randomized controlled trial, 70 healthy parturients were allocated to either a bolus group or an infusion group. At cord clamping, participants in the bolus group received carbetocin 100 µg as a rapid intravenous bolus, while participants in the infusion group received carbetocin 100 µg over 10 min. The primary outcome was the variation in maternal heart rate from baseline during the 20 min following cord clamping. Secondary outcomes included blood pressure, cardiac output, and stroke volume variations during the study period, measured with the ClearSight™ hemodynamic monitor. RESULTS: Maximum heart rate variation was not different between the groups: bolus group, mean (standard deviation) 29.8 (25.2)% vs infusion group, 27.2 (23.3)%; P = 0.67. The increase in heart rate occurred significantly earlier in the bolus group than in the infusion group (median [interquartile range] time, 105 [69-570] sec vs 485 [255-762] sec; P = 0.02; group × time interaction: two-way repeated measures ANOVA, P = 0.04). There was no significant difference in maximum variations for the other hemodynamic parameters between the groups. CONCLUSION: Carbetocin infused over ten minutes did not reduce the magnitude of maternal heart rate variation but delayed its occurrence. This finding could be relevant to the anesthesiologist caring for parturients in whom a slight increase in maternal heart rate is clinically undesirable. STUDY REGISTRATION: www. CLINICALTRIALS: gov (NCT03404544); registered 19 January 2018.

RéSUMé: OBJECTIF: Lorsque la carbétocine, un analogue de l'ocytocine, est administrée à titre de prophylaxie pour les hémorragies du post-partum dans les accouchements par césarienne programmée, cet agent provoque fréquemment une tachycardie et une hypotension. Il a été démontré qu'une perfusion de phényléphrine prévenait l'hypotension induite par la rachianesthésie. L'objectif de cette étude était d'évaluer si une perfusion lente de carbétocine réduirait la variation de fréquence cardiaque maternelle et les perturbations hémodynamiques par rapport à un bolus rapide chez les parturientes recevant une perfusion prophylactique de phényléphrine pendant un accouchement par césarienne programmée. MéTHODE: Dans cette étude randomisée contrôlée à double insu, 70 parturientes en bonne santé ont été allouées à un groupe bolus ou à un groupe perfusion. Lors du clampage du cordon, les participantes du groupe bolus ont reçu 100 µg de carbétocine sous forme de bolus intraveineux rapide, tandis que les participantes du groupe perfusion ont reçu 100 µg de carbétocine sur dix minutes. Le critère d'évaluation principal était la variation de la fréquence cardiaque maternelle par rapport aux valeurs de base au cours des 20 minutes suivant le clampage du cordon. Les critères secondaires comprenaient la tension artérielle, le débit cardiaque et les variations du volume d'éjection au cours de la période d'étude, tels que mesurés avec le moniteur hémodynamique ClearSight™. RéSULTATS: La variation maximale de fréquence cardiaque n'était pas différente entre les groupes : groupe bolus, moyenne (écart type) 29,8 (25,2) % vs groupe perfusion, 27,2 (23,3) %; P = 0,67. L'augmentation de la fréquence cardiaque s'est produite significativement plus tôt dans le groupe bolus que dans le groupe perfusion (temps médian [écart interquartile], 105 [69-570] sec vs 485 [255-762] sec; P = 0,02;× interaction groupe x temps : ANOVA bidirectionnelle à mesures répétées, P = 0,04). Il n'y avait pas de différence significative dans les variations maximales pour les autres paramètres hémodynamiques entre les groupes. CONCLUSION: La carbétocine perfusée pendant dix minutes n'a pas réduit l'ampleur de la variation de la fréquence cardiaque maternelle, mais a retardé son apparition. Cette découverte pourrait être pertinente pour l'anesthésiologiste qui prend soin de parturientes chez qui une légère augmentation de la fréquence cardiaque maternelle serait cliniquement indésirable. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03404544); enregistrée le 19 janvier 2018.

Improved clinical outcomes of outpatient enhanced recovery hip and knee replacements in comparison to standard inpatient procedures: A study of patients who experienced both.

BACKGROUND: The benefits of combining enhanced recovery after surgery (ERAS) interventions with an outpatient program for total hip/knee arthroplasty (THA/TKA) are uncertain. This study's main objective was to evaluate adverse events with an ERAS-outpatient compared to standard-inpatient care and secondary objectives were to compare pain, functional recovery, PROMs and satisfaction. HYPOTHESIS: The ERAS-outpatient program would result in reduced adverse events compared to standard-inpatient care. METHODS: An ambidirectional single subject cohort study was conducted on 48 consecutive patients who experienced both a standard-inpatient and an ERAS-outpatient THA/TKA (contralaterally). Adverse event rate according to the Clavien-Dindo scale, the Comprehensive Complications Index (CCI) and the number of unplanned episodes of care were assessed. Postoperative pain on a numeric rating scale, opioid consumption in morphine milligram equivalents, functional recovery, patient reported outcome measures (PROMs) (WOMAC, KOOS, HOOS, Forgotten Joint Score and Patient Joint Perception) and patients' satisfaction were also evaluated. RESULTS: Following the ERAS-outpatient surgery, complication rates were reduced by more than 50% (2.1 vs. 4.4, p<0.001), CCI was significantly lower (12.3 vs. 19.1, p<0.001), and similar unplanned episodes of care were observed (p>0.999). In the first 8 postoperative hours, perceived pain was similar (p>0.805) while opioid consumption was significantly reduced (9.3 vs. 26.5, p<0.001). Patients walked, climbed stairs, showered, performed activities of daily living, practised sports, went back to work sooner (p<0.001), but PROMs were similar between groups at the last follow-up (p>0.188). Patients were more satisfied of the ERAS-outpatient pathway and recommended it significantly more (p<0.002). CONCLUSION: Compared to the conventional inpatient care, the ERAS-outpatient program proved to be safer, enable faster functional recovery, and improve patients' satisfaction which highlight the importance of following ERAS principles when implementing an outpatient THA/TKA program. LEVEL OF EVIDENCE: III; Ambidirectional Cohort study.

"Impact of Nociception Level (NOL) index intraoperative guidance of fentanyl administration on opioid consumption, postoperative pain scores and recovery in patients undergoing gynecological laparoscopic surgery. A randomized controlled trial".

STUDY OBJECTIVE: The Nociception Level (NOL) index uses a multiparametric approach to measure the balance between sympathetic and parasympathetic systems activity. Recently, a strong correlation between the NOL index response to nociceptive stimuli and the level of opioid analgesia during surgery was reported. Others observed that intraoperative doses of remifentanil and sufentanil were reduced when the NOL index was used. So far, no study has evaluated the impact of NOL-guided fentanyl antinociception in laparoscopic gynecological surgery. The primary hypothesis of this present study was to evaluate whether intraoperative NOL-guided fentanyl administration would reduce intra-operative opioid consumption. Secondary hypotheses were to assess whether this would lead to lower postoperative opioid consumption and pain scores, as well as improved postoperative outcomes. SETTING: University hospital, operating room. PATIENTS: 70 adult patients, ASA 1-3, scheduled for total laparoscopic hysterectomy. INTERVENTIONS: Patients were randomized into 2 groups: SOC (standardization of care) and NOL (using the NOL index to guide the administration of fentanyl). The depth of anesthesia was monitored with BIS™. Intraoperative fentanyl boluses were administered based on heart rate and mean arterial pressure variations in the SOC group, and NOL index for the NOL group. MEASUREMENTS: Fentanyl total intraoperative dose administered was collected and also averaged per hour. Pain scores and hydromorphone consumption were assessed in the post-anesthesia care unit and up to 24 h. MAIN RESULTS: Sixty-six patients completed the study, 33 in each group. Total intraoperative fentanyl administration was not different between the two groups (217 (70) in the NOL group vs 280 (210) in the SOC group (P = 0.11)). Nevertheless, intraoperative fentanyl administration per hour was reduced by 25% in the NOL-guided group compared to the SOC group: 81 (24) vs 108 (66) µg.h-1, respectively (P = 0.03). Hydromorphone consumption and pain scores in the post-anesthesia care unit and at 24 h were not significantly different between the two groups. CONCLUSION: NOL-guided analgesia allowed for a 22% reduction of the total amount of intraoperative fentanyl which was not significant. Nevertheless, results reported a significant reduction by 25% in the doses of fentanyl averaged per hour of surgery and administered in the NOL-guided group compared with the standardized practice in laparoscopic gynecological surgery. The pain measured postoperatively was similar in the two groups while the average postoperative consumption of opioids to achieve the same level of pain scores in post-anesthesia care unit and at 24 h was not significantly reduced. Further larger multicenter studies centered towards postoperative outcomes are needed.

Ultrasound evaluation of inferior vena cava compression in tilted and supine term parturients.

PURPOSE: Hypotension is common following spinal anesthesia (SA) during elective Cesarean delivery (CD). Although common practice is to alleviate inferior vena cava (IVC) compression, limited evidence supports a 15° tilt for CD. We measured collapsibility of the IVC in supine and 15° left lateral tilt positions with ultrasound before and after SA and phenylephrine infusion in term parturients. METHODS: Twenty term parturients scheduled for CD were recruited for this prospective study. Ultrasound measurements of the IVC were taken 1) supine before SA, 2) tilted 15° before SA, 3) supine after SA, and 4) tilted 15° after SA. A phenylephrine infusion was begun after injection of SA. The primary outcome was to evaluate the impact of position on the IVC collapsibility index (IVCCI): a measure of the difference between the maximum and minimum IVC diameter with respiration. RESULTS: The mean (standard deviation) IVCCI (%) before SA was higher in the supine 19.5 (8.0) than in the tilted 15.0 (6.4) position (mean difference, 4.5; 95% confidence interval [CI], 0.1 to 8.9; P = 0.04). After SA, there was no significant difference between IVCCI (%) in the supine 17.8 (8.3) and tilted 14.2 (6.9) position (mean difference, 3.5; 95% CI, -0.9 to 7.9; P = 0.13). There was no correlation between the pre-spinal IVVCI measurements and the quantity of phenylephrine used during the surgery. CONCLUSION: The IVCCI was lower in the 15° tilt position than in the supine position, but not after SA with a phenylephrine infusion. Ultrasound imaging can help identify IVC compression. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03410199); registered 18 January 2018.

RéSUMé: OBJECTIF: L'hypotension est fréquente après une rachianesthésie pendant un accouchement par césarienne programmée (CP). Bien que la pratique courante consiste à atténuer la compression de la veine cave inférieure (VCI), des données probantes limitées encouragent une latéralisation de 15 ° durant la CP. Avec l'échographie, nous avons mesuré la collapsibilité de la VCI en décubitus dorsal et en position d'inclinaison latérale gauche de 15° avant et après la rachianesthésie et la perfusion de phényléphrine chez des parturientes à terme. MéTHODE: Vingt parturientes à terme devant subir une CP ont été recrutées dans le cadre de cette étude prospective. Les mesures échographiques de la VCI ont été prises 1) en décubitus dorsal avant la rachianesthésie, 2) avec une latéralisation de 15° avant la rachianesthésie, 3) en décubitus dorsal après la rachianesthésie, et 4) avec une latéralisation de 15° après la rachianesthésie. Une perfusion de phényléphrine a été amorcée après l'injection de la rachianesthésie. Le critère d'évaluation principal était l'impact de la position sur l'indice de collapsibilité de la VCI (ICVCI), soit une mesure de la différence entre les diamètres maximal et minimal de la VCI avec respiration. RéSULTATS: Le ICVCI moyen (écart type) (%) avant la rachianesthésie était plus élevé en décubitus dorsal, à 19,5 (8,0), qu'en position latéralisée, à 15,0 (6,4) (différence moyenne, 4,5; intervalle de confiance [IC] 95 %, 0,1 à 8,9; P = 0,04). Après la rachianesthésie, aucune différence significative n'a été observée entre l'ICVCI (%) en décubitus dorsal, à 17,8 (8,3), et en position latéralisée, à 14,2 (6,9) (différence moyenne, 3,5; IC 95 %, -0,9 à 7,9; P = 0,13). Il n'y avait aucune corrélation entre les mesures de l'ICVCI pré-rachianesthésie et la quantité de phényléphrine utilisée pendant la chirurgie. CONCLUSION: L'ICVCI était plus bas en position latéralisée à 15 ° qu'en décubitus dorsal, mais pas après une rachianesthésie avec une perfusion de phényléphrine. L'échographie peut aider à identifier la compression de la VCI. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03410199); enregistrée le 18 janvier 2018.

A randomized controlled trial comparing nociception level (NOL) index, blood pressure, and heart rate responses to direct laryngoscopy versus videolaryngoscopy for intubation: the NOLint project.

PURPOSE: The effect of direct laryngoscopy using a Macintosh blade (MAC) vs GlideScope™ videolaryngoscopy using a Spectrum LoPro blade (GVL) on nociceptive stimulation has not been quantitatively studied. This study used the new nociception level (NOL) index to compare the nociceptive response induced by GVL or MAC during laryngoscopy with or without intubation. METHODS: Patients underwent two laryngoscopies at four-minute intervals (L1, L2), one with GVL and the other with MAC (first randomization). A third laryngoscopy (L3) followed by tracheal intubation was performed four minutes after L2 (GVL or MAC, second randomization). Nociception was quantitatively assessed by NOL and standard hemodynamic parameters (heart rate [HR] and mean arterial pressure). For the crossover design, blade comparisons accounted for sequence and blade type. A possible carryover effect between laryngoscopies was assessed. RESULTS: In the 50 patients randomized, there was no carryover effect from one laryngoscopy to the next for all analyzed parameters. Nociception level index peak values were higher with MAC than GVL. Analysis of ΔNOL showed a lower nociceptive response with GVL for L1+L2 combined. Mean peak NOL values were significantly higher after L3+intubation than after L1+L2, for both GVL and MAC groups. Analysis of ΔHR values did not show a significant difference between GVL and MAC for any laryngoscopy. CONCLUSION: Laryngoscopy alone with GVL induces less nociception than with MAC. The NOL was more sensitive than HR at detecting nociceptive responses to MAC vs GVL. Additionally, and irrespective of which technique/blade was used, the combination of laryngoscopy + tracheal intubation produced a much greater nociceptive response than the laryngoscopy alone. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03277872); registered 29 August 2017.

RéSUMé: OBJECTIF: L'effet de la laryngoscopie directe avec une lame Macintosh (MAC) par rapport à la vidéolaryngoscopie à l'aide d'un GlideScope™ avec lame Spectrum LoPro (GVL) sur la stimulation nociceptive n'a pas été quantitativement étudié. Cette étude a utilisé le nouvel indice de niveau de nociception (NOL) pour comparer la réponse nociceptive induite par une laryngoscopie avec GVL ou MAC avec ou sans intubation. MéTHODE: Les patients ont subi deux laryngoscopies à des intervalles de quatre minutes (L1, L2), l'une par GVL et l'autre par MAC (première randomisation). Une troisième laryngoscopie (L3) suivie d'une intubation trachéale a été effectuée quatre minutes après L2 (GVL ou MAC, deuxième randomisation). La nociception a été quantitativement évaluée à l'aide de l'indice NOL, et les paramètres hémodynamiques standard (fréquence cardiaque [FC] et pression artérielle moyenne) ont été mesurés. Dans le volet croisé de l'étude, les comparaisons de lames ont tenu compte de la séquence et du type de lame. La possibilité d'un effet de persistance entre les laryngoscopies a été évaluée. RéSULTATS: Chez les 50 patients randomisés, il n'y a eu aucun effet de persistance d'une laryngoscopie à la suivante pour tous les paramètres analysés. Les valeurs maximales de l'indice de nociception étaient plus élevées avec les lames MAC qu'avec la vidéolaryngoscopie GVL. L'analyse de ΔNOL a montré une réponse nociceptive inférieure avec la vidéolaryngoscopie GVL pour L1+L2 combinés. Les valeurs maximales moyennes de NOL étaient significativement plus élevées après L3+intubation qu'après L1+L2, tant pour les groupes GVL que MAC. L'analyse des valeurs ΔFC n'a pas montré de différence significative entre les techniques GVL et MAC pour quelque laryngoscopie que ce soit. CONCLUSION: La laryngoscopie seule avec le GlideScope induit moins de nociception qu'avec une lame MAC. L'indice NOL était plus sensible que les FC pour détecter les réponses nociceptives à la laryngoscopie MAC vs GVL. En outre, et indépendamment de la technique/lame utilisée, la combinaison de laryngoscopie + intubation trachéale a produit une réponse nociceptive beaucoup plus importante que la laryngoscopie seule. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03277872); enregistrée le 29 août 2017.

Uterine Exteriorization Compared With In Situ Repair of Hysterotomy After Cesarean Delivery: A Randomized Controlled Trial.

OBJECTIVE: To compare the effect of exteriorized with in situ uterine repair on intraoperative nausea and vomiting during elective cesarean delivery under spinal anesthesia using a phenylephrine infusion. METHODS: This study was a randomized double-blinded controlled trial of 180 women undergoing elective cesarean delivery using a standardized anesthetic protocol. Patients were randomized to exteriorization (n=90) or in situ uterine repair (n=90). The spinal anesthetic, phenylephrine infusion, and blood pressure management were all standardized. The primary outcome was postdelivery intraoperative nausea and vomiting using a 4-point scale (0-3). A sample size of 80 patients per group was needed to demonstrate a 50% reduction in intraoperative nausea and vomiting with in situ repair. RESULTS: From November 2015 through July 2018, 180 patients were enrolled. Incidence of postdelivery intraoperative nausea and vomiting was 39% in the exteriorization group compared with 22% in the in situ group (P=.01). Incidence of hypotension (80% vs 50%; P<.001) and tachycardia (33% vs 17%; P=.02) was significantly higher in the exteriorization group, and more phenylephrine boluses were administered to this group (median 4 boluses [first and third quartiles 1.25-7] vs 2 [0-4]; P<.001). The duration of surgery, blood loss, and postoperative hemoglobin decline were similar between groups. CONCLUSION: In situ uterine repair for elective cesarean delivery under spinal anesthesia with a phenylephrine infusion is associated with less postdelivery intraoperative nausea and vomiting. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02587013.

Enhanced recovery short-stay hip and knee joint replacement program improves patients outcomes while reducing hospital costs.

INTRODUCTION: An attractive option to reduce hospital length of stay (LOS) after hip or knee joint replacement (THA, TKA) is to follow the Enhanced Recovery After Surgery principles (ERAS) to improve patient experience to a level where they will feel confident to leave for home earlier. The objective of this study was to evaluate the implementation of short-stay protocol following the ERAS principles. HYPOTHESIS: We hypothesized that our ERAS THA and TKA short-stay protocol would result in a lower complication rate, shorter hospital LOS and reduced direct health care costs compared to our standard procedure. MATERIAL AND METHODS: We compared the complications rated according to Clavien-Dindo scale, hospital LOS and costs of the episode of care between a prospective cohort of 120 ERAS short-stay THA or TKA and a matched historical control group of 150 THA or TKA. RESULTS: Significantly lower rate of Grade 1 and 2 complications in the ERAS short-stay group compared with the standard group (mean 0.8 vs 3.0, p<0.001). No difference was found between the 2 groups for Grade 3, 4, or 5 complications. The mean hospital LOS for the ERAS short-stay group decreased by 2.8 days for the THAs (0.1 vs 2.9 days, p<0.001) and 3.9 days for the TKAs (1.0 vs 4.9 days, p<0.001). The mean estimated direct health care costs reduction with the ERAS short-stay protocol was 1489 CAD per THA and 4158 CAD per TKA. DISCUSSION: In many short-stay protocols, focus has shifted from ERAS goals of a reduction in complications and improved recuperation to use length of stay as the main factor of success. Implementation of an ERAS short-stay protocol for patients undergoing THA or TKA at our institution resulted not only in reduced hospital LOS, but also in improved patient care and reduced direct health care costs. LEVEL OF EVIDENCE: Level II.

Dexmedetomidine Versus Remifentanil for Monitored Anesthesia Care During Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: A Randomized Controlled Trial.

BACKGROUND: We hypothesized that, compared to remifentanil, dexmedetomidine used for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) performed under monitored anesthesia care (MAC) in nonintubated patients would result in fewer episodes of major respiratory adverse events (number of episodes of bradypnea, apnea or desaturation) but no difference in satisfaction with perioperative conditions. METHODS: Sixty (American Society of Anesthesiologists physical status I-III) patients scheduled to undergo EBUS-TBNA under MAC were randomized to receive either remifentanil (0.5 µg/kg IV bolus) in 10 minutes, followed by 0.05-0.25 µg/kg/min, or dexmedetomidine (0.4 µg/kg IV bolus) in 10 minutes, followed by 0.5-1.0 µg/kg/h. The primary outcome was the number of major respiratory adverse events (bradypnea, apnea, or hypoxia). The secondary outcomes included hemodynamic variables, discharge time from the postanesthesia care unit, endotracheal lidocaine use, patient's sedation using the Observer Assessment of Alertness/Sedation Scale, operative conditions, operator and patient satisfaction, pain, coughing, vocal cord mobility, recall, and nausea/vomiting. RESULTS: Dexmedetomidine produced significantly fewer episodes of major respiratory events (bradypnea, apnea, or desaturation), with 0 [0-0.5] episodes versus 2 [0-5] (median [interquartile range]) (P = .001), than did remifentanil. Fewer episodes of bradypnea or apnea (dexmedetomidine: 0 [0-0] versus remifentanil: 0 [0-0.5]; P = .031), and fewer episodes of desaturation (dexmedetomidine: 0 [0-0.5] versus remifentanil: 1 [0-4]; P = .039) were recorded in the dexmedetomidine group. The time needed for patients to meet postanesthesia care unit discharge criteria (Aldrete score: 9) after EBUS-TBNA was longer in the dexmedetomidine group (10 [3-37.5] minutes) versus the remifentanil group (3 [3-5] minutes) (P < .001). No differences were observed in the 2 groups for sedation depth (Observer Assessment of Alertness/Sedation Scale), endotracheal lidocaine use, operative conditions, operator and patient satisfaction, pain, coughing, vocal cord mobility, recall, and nausea/vomiting episodes. CONCLUSIONS: Dexmedetomidine resulted in fewer respiratory adverse events during EBUS-TBNA under MAC, when compared to remifentanil, with no difference in overall operative conditions. However, dexmedetomidine use was associated with delayed postoperative discharge.

The use of Invos™ somatic oximetry to measure variations in placental tissue oxygenation in laboring healthy term parturients with epidural analgesia: an observational study.

PURPOSE: Near-infrared spectroscopy provides a non-invasive continuous real-time monitoring of tissue oxygen saturation. As uterine contractions during labor may be associated with a transient uteroplacental hypoperfusion, this prospective, observational study investigates the ability of near-infrared spectroscopy to detect variation in uteroplacental oximetry during uterine contractions. PATIENTS AND METHODS: Four Invos™ oximetry probes (Medtronic®, Minneapolis, MN, USA) per subjects were applied on the placental surface (PLA), the abdomen (MYO), the forearm (ARM) and the leg (LEG), of twenty healthy laboring parturients with epidural analgesia. Measurements of mean tissue oxygen saturation and area under the curve (AUC) were made during 60 minutes. The primary outcome was the difference of the AUC measurements between the PLA probe and the MYO probe. RESULTS: The AUC values for the PLA and MYO probes were not different. The mean saturation values recorded by the PLA probe were not different from the other probes. CONCLUSION: The Invos monitor was unable to detect variations in uteroplacental saturation during labor in healthy parturients.

Minimum effective fluid volume of colloid to prevent hypotension during caesarean section under spinal anesthesia using a prophylactic phenylephrine infusion: An up-down sequential allocation study.

STUDY OBJECTIVE: The aim of this study was to de termine the minimum effective fluid volume (MEFV) of hydroxyethyl starch 130/0.4 (HES) infused in a preload fashion which would prevent hypotension in 50% of parturients undergoing caesarean section. A secondary objective was to measure the hemodynamic effect of fluid loading on the subjects. DESIGN: This is a prospective, double-blinded, dose-finding study using an up-down sequential allocation design. SETTING: In the operating room. PATIENTS: Thirty healthy parturients undergoing caesarean section under spinal anesthesia using a prophylactic phenylephrine infusion were included in this study. INTERVENTION: The initial HES volume infused in the first patient was 500 mL. A failure of treatment to HES preload was defined as a single episode of systolic hypotension below 20% of baseline value. The next patient in the sequence was given a volume of HES adjusted by either an increment or a decrement of 100 mL according to the previous subject response to fluid preload. MEASUREMENTS: Stroke volume and cardiac output were measured with a bioreactance-based non-invasive cardiac output monitor (NICOM). MAIN RESULTS: The MEFV of HES was 733 mL (95% CI: 388-917 mL). Fluid loading before the administration of the spinal anesthesia resulted in an increase in stroke volume and cardiac output. The combined effect of spinal anesthesia and a phenylephrine infusion reduced the maternal heart rate and cardiac output, but not the stroke volume. CONCLUSION: Our study is the first to investigate variable fluid loading volumes in this population. A HES preload of approximatively 700 mL prevented maternal hypotension in 50% of the parturients under the conditions of this study. We suggest that up-down sequential allocation design is a useful tool to compare different fluid loading regimens in this setting.

Fluid and vasopressor management for Cesarean delivery under spinal anesthesia: continuing professional development.

PURPOSE: The purpose of this Continuing Professional Development module is to review the physiology of maternal hypotension induced by spinal anesthesia in pregnant women, and the effects of fluids and vasopressors. PRINCIPAL FINDINGS: Maternal hypotension induced by spinal anesthesia is caused mainly by peripheral vasodilatation and is not usually associated with a decrease in cardiac output. Although the intravenous administration of fluids helps to increase cardiac output, it does not always prevent maternal hypotension. Three strategies of fluid administrations are equivalent for the prevention of maternal hypotension and a reduced need for vasopressors: (1) colloid preload; (2) colloid coload; and (3) crystalloid coload. Crystalloid preload is not as effective as any of those three strategies. Unlike phenylephrine, ephedrine can cause fetal acidosis. Therefore, phenylephrine is recommended as first line treatment of maternal hypotension. A phenylephrine infusion (25-50 µg x min(-1)) appears to be more effective than phenylephrine boluses to prevent hypotension, and nausea and vomiting. In pre-eclamptic patients, spinal anesthesia produces less hypotension than in normal pregnant women and fluid volumes up to 1,000 mL are usually well tolerated. Therefore mild to moderate intravascular volume loading is recommended, keeping in mind the increased risk for pulmonary edema in this population. In pre-eclamptic patients, hypotension can be treated either with ephedrine or phenylephrine, and phenylephrine infusions are not recommended. CONCLUSION: A volume loading regimen other than crystalloid preload should be adopted. A phenylephrine infusion during elective Cesarean delivery is beneficial for the mother and safe for the newborn.

Does the baricity of bupivacaine influence intrathecal spread in the prolonged sitting position before elective cesarean delivery? A prospective randomized controlled study.

BACKGROUND: Difficulties in inserting an epidural catheter while performing combined spinal-epidural anesthesia for cesarean delivery may lead to undue delays between the spinal injection of the local anesthetic mixture and the adoption of the supine position with lateral tilt. We hypothesized that this delay may affect the intrathecal distribution of local anesthetic of different baricities such that hypobaric local anesthetic would lead to a higher sensory block level. METHODS: Healthy parturients with uncomplicated pregnancies undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled in this prospective double-blind randomized controlled trial. The subjects were allocated to receive hyperbaric (hyperbaric group), isobaric (isobaric group), or hypobaric (hypobaric group) spinal bupivacaine 10 mg. After the spinal injection, the subjects remained in the sitting position for 5 minutes (to simulate difficulty in inserting the epidural catheter) before being helped into the supine lateral tilt position. The primary outcome was the sensory block level during the 25 minutes after the spinal injection. Other end points included motor block score, maternal hypotension, and vasopressor requirements. RESULTS: Data from 89 patients were analyzed. Patient characteristics were similar in all groups. The median [interquartile range] (95% confidence interval) sensory levels after spinal injection were significantly higher with decreasing baricity: hyperbaric T10 [T11-8] (T10-9), isobaric T9 [T10-7] (T9-7), and hypobaric T6 [T8-4] (T8-5) (P < 0.001, Cuzick trend). All patients in the hypobaric group reached a sensory block level of T4 at 25 minutes after spinal injection compared with 80% of the patients in both the isobaric and hyperbaric groups (P = 0.04; difference 20%, 95% confidence interval of difference 4%-33%). Significantly more patients in the hypobaric group had complete lower limb motor block (Bromage score = 4) (hyperbaric 43%, isobaric 63%, and hypobaric 90%; P < 0.001). The incidences of maternal hypotension and nausea and vomiting were similar among groups, although the ephedrine requirements were significantly increased in the isobaric and hypobaric groups by factors of 1.83 and 3.0, respectively, compared with the hyperbaric group (P < 0.001, Cuzick trend). CONCLUSIONS: We demonstrated that when parturients undergoing cesarean delivery were maintained in the sitting position for 5 minutes after spinal injection of the local anesthetic, hypobaric bupivacaine resulted in sensory block levels that were higher compared with isobaric and hyperbaric bupivacaine, respectively, during the study period.

Cesarean delivery in the obese parturient: anesthetic considerations.

Obesity is a worldwide health problem and its prevalence is reaching epidemic proportions. As obesity does not spare women of childbearing age, obstetric anesthesiologists will increasingly be exposed to the challenges of anesthesia in this population. The purpose of this article is to give the reader a thorough understanding of the anesthetic implications of obesity relating to cesarean deliveries. Obesity is associated with hypertension, diabetes, obstructive sleep apnea and other comorbidities. It increases the risk of cesarean delivery, postpartum wound infections and deep venous thromboembolism. Obese parturients are prone to anesthetic complications such as aspiration of gastric contents, difficult monitoring, positioning, airway management and challenging neuraxial techniques. A thorough precesarean delivery preparation should include an evaluation by an anesthesiologist for women with a BMI over 40 kg/m² and institution of an antacid prophylaxis protocol, thromboprophylaxis and antibiotic prophylaxis. Regional anesthesia should ideally be used in all obese parturients unless contraindicated. The goals of postpartum care include efficacious analgesia, physiotherapy and early mobilization. Monitoring and vigilance in an intensive care unit or step-down units should be considered for morbidly obese women.