J. Fusciardi

Changes in platelet count after cardiac surgery can effectively predict the development of pathogenic heparin-dependent antibodies

Cardiopulmonary bypass (CPB) induces the release of platelet factor 4 (PF4) and patients are at risk of heparin‐induced thrombocytopenia (HIT). This study was aimed to determine whether an abnormal evolution in platelet count (PC) after CPB is predictive of the development of HIT antibodies. Two abnormal PC patterns were defined: pattern P1, characterized by a decrease in PC following previous correction of thrombocytopenia occurring during CPB, and pattern P2, defined as a persistent low PC in the days following CPB. PC was evaluated for 10 d in 305 consecutive patients before and after CPB. Serotonin release assay (SRA) was carried out between days 8 and 10 to detect pathogenic heparin‐dependent antibodies. Moreover, antibodies to heparin–PF4 (H–PF4) complexes were assayed by enzyme‐linked immunosorbent assay. PC evolution after CPB was normal in 300 patients although antibodies to H–PF4 were frequently present (53·4%). Changes in PC were abnormal in five patients with pattern P1 (n = 4) or P2 (n = 1). As SRA was positive in four of the five cases, the positive predictive value of abnormal PC pattern for pathogenic HIT antibodies was 80%. Careful follow‐up of PC after CPB makes it possible to predict with high specificity (99%) for those patients who develop pathogenic HIT antibodies.

The early and delayed analgesic effects of ketamine after total hip arthroplasty: a prospective, randomized, controlled, double-blind study.

BACKGROUND: Ketamine has been shown to have a morphine-sparing effect soon after surgery. Nevertheless, whether this effect still exists after being combined with nonsteroidal antiinflammatory drugs and acetaminophen, and whether ketamine can decrease chronic pain after nononcologic surgery remain unclear. Thus, we designed a study to assess ketamine’s effect on acute and chronic postoperative pain when combined with multimodal analgesia after total hip arthroplasty (THA). METHODS: Patients scheduled for primary nononcologic THA using standardized general anesthesia were randomized. They received IV ketamine before incision (0.5 mg/kg), and a 24-h infusion (2 &mgr;g · kg−1 · min−1) or a similar blinded saline bolus and infusion. Postoperative analgesia included IV acetaminophen, ketoprofen, plus morphine/droperidol patient-controlled analgesia for 48 h. Data pertaining to pain scores, morphine consumption, and need for crutches were collected for 6 mo after THA. Our primary outcome was 24-h morphine consumption. RESULTS: One hundred fifty-four patients were included (placebo, 75; ketamine, 79). Patients and operative data were similar in both groups. Ketamine decreased morphine consumption at 24 h from 19 ± 12 mg to 14 ± 13 mg (P = 0.004). At Day 30, ketamine decreased the proportion of patients needing 2 crutches or a walking frame from 56% to 31% (P = 0.0035). From Day 30 to Day 180, ketamine decreased the proportion of patients with persistent pain at rest in the operated hip (P = 0.008). At Day 180, 21% of placebo group patients (15 of 70) experienced pain at rest in the operated hip versus 8% (6 of 72) in the ketamine group (P = 0.036, odds ratio 0.33, 95% confidence interval 0.12–0.91, risk reduction 67%). CONCLUSIONS: Ketamine had a morphine-sparing effect after THA, even when morphine was combined with multimodal systemic analgesia. It also facilitated rehabilitation at 1 mo and decreased postoperative chronic pain up to 6 mo after surgery.

The Feasibility of Ultrasound to Assess Subglottic Diameter

BACKGROUND:In healthy patients, the narrowest diameter of the subglottic upper airway is the width of the air-column at the level of the cricoid cartilage. This diameter governs the selection of the endotracheal tube size, as excessive tube diameter may damage the tracheal mucosa leading to postextubation stridor or subglottic stenosis. Unfortunately, selecting endotracheal tube size based on height, weight, or age does not reliably lead to the proper tube. The knowledge of airway diameter, especially using a bedside noninvasive tool, could therefore be helpful in anesthesia and intensive care. METHODS:We studied 19 healthy volunteers (27 ± 3 yr, nine females) to compare the transverse diameter of the cricoid lumen assessed by ultrasonography and magnetic resonance imaging. RESULTS:We found a strong correlation between the two techniques (r = 0.99, P < 0.05) confirmed by Bland–Altman analysis with a bias of 0.14 mm, a precision of 0.33 mm, and limits of agreement of −0.68 mm/0.96 mm. CONCLUSION:In young healthy adults, ultrasonography appeared to be a reliable tool to assess the diameter of the subglottic upper airway.

The reduction of preoperative autologous blood donation for primary total hip or knee arthroplasty: the effect on subsequent transfusion rates.

We conducted this quality assurance observational study to examine the effects of a change in policy regarding preoperative autologous blood donation (PABD) and indications for perioperative blood transfusion in patients undergoing primary total hip or knee arthroplasty. Two successive time periods, each including 182 successive patients treated by the same medical team and with standardized anesthesia, were compared. The first study had the following standard transfusion policy: 3 U of PABD collected (n = 119) and liberal autologous transfusion (AT). The second study introduced a specific indication for PABD, on the basis of estimated red blood cell reserve and a life expectancy of more than 10 years; 2 U of PABD was collected (n = 81), and criteria were identical for AT and allogeneic transfusion. We mainly compared the incidence of AT; allogeneic and overall transfusions; the inclusion, admission, and discharge hematocrit values; and the wastage of PABD units. This novel policy increased the number of untransfused patients by a factor of 10 (5.5% vs 56.6%) (P < 0.0001), decreased the number of PABD patients by 30% with a 2.4-fold reduction in AT (30% vs 80%) (P < 0.0001), and did not change allogeneic requirements (13% vs 15%). Although fewer autologous units were collected (172 vs 426), the wastage was higher in Study 2 (46% vs 12%) (P < 0.0001). We conclude that incorporation of patients’ individual factors improves the efficiency of transfusion for total hip and total knee arthroplasty surgeries.

Elastomeric pump reliability in postoperative regional anesthesia: a survey of 430 consecutive devices.

BACKGROUND:Postoperative analgesia via continuous perineural infusion of local anesthetics compares favorably with systemic analgesia. Elastomeric pumps increase patient satisfaction compared with electronic models. In in vitro investigations, infusions remained within 15% of their designated set rates. We assessed in vivo the infusion rate of elastomeric pumps in regional analgesia after orthopedic surgery. METHODS:All consecutive elastomeric pumps were retrospectively studied during a 10-mo period. Perineural catheters were inserted preoperatively and connected postoperatively to elastomeric pumps filled with ropivacaine 0.2%. Before infusion, elastomeric pumps and ropivacaine were stored at room temperature. Two models of pumps were randomly used: Infusor™ LV5 (Baxter, France) or Easypump™ (Braun, Germany), both set at 5 mL/h. Nurses weighed the devices at the bedside using a portable electronic scale several times a day until catheter removal. Weights over time allowed accurate deflation profile assessment and flow rate calculation. An unchanged weight over time indicated either an obstructed catheter or an ineffective device. RESULTS:After connection to the catheter, 88 devices did not deflate (80 Easypump of 300 and 8 Infusor of 130, P < 0.0001). One Easypump was impossible to deflate, even after disconnection from its catheter. In two cases, catheters were obstructed. In 21 cases, catheters were removed 11 to 72 h later without being tested for patency. In 24 cases, pumps correctly deflated after catheters were injected without difficulty with a local anesthetic bolus. The remaining 40 devices spontaneously started to deflate 6 to 43 h after their connection. These 88 elastomeric pumps were associated with higher maximal visual analog scale scores during the first postoperative night than devices showing immediate deflation after connection (34 ± 21 mm vs 26 ± 19 mm, P = 0.006). Flow rates were calculated over a mean period of 54 ± 18 h (Easypump) and 49 ± 19 h (Infusor). The flow rates differed from those set by manufacturers (5 mL/h ± 15%) in 47% of Easypump and in 34% of Infusor devices (P = 0.01). CONCLUSIONS:In vivo reliability of elastomeric pumps is different than in vitro. In the event of early insufficient postoperative perineural analgesia, an absence of deflation of the elastomeric pump must be considered. We recommend weighing these devices every 3 h during the first 24 h of infusion.

Is the musculocutaneous nerve really in the coracobrachialis muscle when performing an axillary block? An ultrasound study.

BACKGROUND: In reference textbooks describing axillary block, the ulnar, radial, and median nerves are located in a common sheath surrounding the axillary artery. In contrast, the musculocutaneous nerve is described as lying outside this sheath in the coracobrachialis muscle. In a recent case report of ultrasound-guided axillary block, the musculocutaneous nerve was joined to the median nerve outside this muscle. Our study evaluated the prevalence of atypical musculocutaneous nerve localizations during axillary block. METHODS: All patients undergoing ultrasound-guided axillary block were included from December 2006 to December 2008. Before needle insertion, musculocutaneous, median, ulnar, and radial nerves were localized using ultrasound. Nerve stimulation confirmed atypical nerve localization. After injection of local anesthetics, musculocutaneous and median nerve anatomical relationships were observed. RESULTS: The musculocutaneous nerve was outside the coracobrachialis muscle in 83 of the 387 analyzed blocks (22%). It was near the axillary artery in 22 cases (6%). The musculocutaneous and median nerves appeared as a common neural structure in 61 cases (16%). After local anesthetic injection, a common trunk persisted in 16 of 61 cases (26%), musculocutaneous and median nerves separated in 37 cases (61%), and 2 roots of the median nerve appeared (with or without a separated musculocutaneous nerve) in 6 cases (10%). Two cases (3%) remained undefined. Ulnar nerve location of the 83 patients with atypical musculocutaneous nerve position differed from the ones with a classical musculocutaneous nerve localization. CONCLUSIONS: During axillary block, the musculocutaneous nerve is outside the coracobrachialis muscle in 1 of 5 patients. This atypical location should be considered during performance of axillary blockade to avoid repeated IM puncture.

Non-invasive ventilation corrects alveolar hypoventilation during spinal anesthesia.

PurposeTo document and explain the beneficial effects of non-invasive ventilation in correcting hypoxemia and hypoventilation in severe chronic obstructive pulmonary disease, during spinal anesthesia in the lithotomy position.Clinical featuresA morbidly obese patient with severe chronic obstructive pulmonary disease underwent prostate surgery in the lithotomy position under spinal anesthesia. Hypoxemia was encountered during surgery, and a profound decrease of forced vital capacity associated with alveolar hypoventilation and ventilation/ perfusion mismatching were observed. In the operating room, an M-mode sonographic study of the right diaphragm was performed, which confirmed that after spinal anesthesia and assuming the lithotomy position, there was a large decrease (-30%) in diaphragmatic excursion. Hypoxemia and alveolar hypoventilation were successfully treated with non-invasive positive pressure ventilation.ConclusionsIntraoperative application of non-invasive positive pressure ventilation improved diaphragmatic excursion and overall respiratory function, and reduced clinical discomfort in this patient.RésuméObjectifMettre en évidence ľefficacité de la ventilation non effractive peropératoire pour corriger les effets délétères de ľassociation bronchopneumopathie chronique obstructive, obésité, rachianesthésie et position de lithotomie.Eléments cliniquesPendant une opération de la prostate réalisée sous rachianesthésie en position de lithotomie, nous avons observé : une hypoxémie liée à une majoration de ľhypoventilation alvéolaire et un effondrement de la capacité vitale forcée. Une étude échographique du diaphragme nous a permis de rattacher ces troubles à une réduction de plus de 30 % de la cinétique du diaphragme. Le traitement a consisté en la mise en place peropératoire ďune ventilation non effractive au masque facial.ConclusionLa ventilation non effractive, en restaurant la cinétique diaphragmatique, a corrigé ľhypoxémie, rétablit la capacité vitale forcée et amélioré le confort respiratoire du patient.Objectif Mettre en evidence ľefficacite de la ventilation non effractive peroperatoire pour corriger les effets deleteres de ľassociation bronchopneumopathie chronique obstructive, obesite, rachianesthesie et position de lithotomie.

La sédation au propofol permet l’intubation difficile vigile avec le masque laryngé FastrachTM

ObjectifEvaluer l’anesthésie iv à objectif de concentration (AIVOC) avec le propofol pour l’intubation vigile [score de Ramsay égal à 3 (SR 3)] via le masque laryngé FastrachTM (MLF).MéthodesAprès accord, 17 patientes ayant des critères d’intubation difficile (score développé par Arné et coll.

Standard preoxygenation vs two techniques in children.

11), sans prémédication anxiolytique, étaient incluses. Sous monitorage et oxygénation, le propofol était administré en mode AIVOC à cibles successives, 0,6 et 1 μg.mL-1, tout en évaluant le SR : si = 3 (intubation MLF), si < 3 (augmentation par palier de 0,2 μg.mL-1 jusqu’à obtention SR = 3). Une anesthésie locale ; (lidocaïne 5 %) de l’oropharynx était réalisée à 0,6 et 1 μg.mL-1, associée à celle du nasopharynx à 1 μg.mL-1. Un questionnaire standardisé évaluait la mémorisation et la satisfaction de la technique (note /10) au premier jour postopératoire.RésultatsL’insertion du MLF a été pratiquée dans 100 % des cas et l’intubation dans 16 cas sur 17 (un échec). La concentration cible de propofol pour obtenir un SR 3 était de 1,25 ± 0,07 μg.mL-1. L’amnésie a été présente dès que la concentration cible de propofol dépassait 1 μg.mL-1. La technique a été jugée très satisfaisante par les patientes (score de satisfaction médian = 9,4/10). Des incidents à type de toux ou nausées ont été observés respectivement dans 47 % et 5 % des cas. Il n’y a eu aucune intubation oesophagienne ni de désaturation (SpO2 < 95 %).DiscussionLe propofol en mode AIVOC avec un SR 3 permet d’effectuer une intubation vigile sous MLF dans des conditions satisfaisantes. Le MLF pourrait être une alternative possible à la fibroscopie “vigile”.PurposeTo evaluate target controlled infusion anesthesia (TCI) with propofol for conscious intubation [(Ramsay score equal to 3 (RS 3)] through the FastrachTM laryngeal mask airway (LMA)Methods17 consenting and unpremedicated patients, who showed criteria for difficult intubation (score developed by Arné et al.

Prévenir les hallucinations aiguës associées à la perfusion intraveineuse continue de kétamine

11), were monitored and received supplemental oxygen. Propofol was administered by TCI, with successive targets of 0.6 and 1 μg.mL-1, while the RS was evaluated: if = 3, LMA intubation was attempted, if < 3 the TCI was increased by steps of 0.2 μg.mL-1 until an RS of 3 was reached. Local anesthesia (lidocaine 5%) of the oropharynx was carried out at 0.6 and 1 μg.mL-1, together with local anesthesia of the nasopharynx at 1 μg.mL-1. A standardized questionnaire evaluated memory of and satisfaction with the technique (score/10) on postoperative day 1.ResultsThe LMA was inserted in 100% of cases and intubation was successful in 16 out of 17 cases (one failure). The propofol target concentration to obtain a RS of 3 was 1.25 ± 0.07 μg.mL-1. Amnesia occurred as soon as the target concentration of propofol exceeded 1 μg.mL-1. The patients found the technique very satisfactory (median satisfaction score = 9.4/10). Incidents of coughing or nausea were observed in 47% and 5% of cases respectively. There was no oesophageal intubation and no desaturation (Sp02 < 95%).ConclusionPropofol administered by TCI to achieve a RS of 3 allows conscious intubation to be performed through a LMA under satisfactory conditions. A LMA could be a possible alternative to a “conscious” fibroscopy.