Inside anesthesia breathing circuits: time to reach a set sevoflurane concentration in toddlers and newborns: simulation using a test lung.

We measured the time it takes to reach the desired inspired anesthetic concentration using the Primus (Drägerwerk, AG, Lübeck, Germany) and the Avance (GE Datex-Ohmeda, Munich, Germany) anesthesia machines with toddler and newborn ventilation settings. The time to reach 95% of inspired target sevoflurane concentration was measured during wash-in from 0 to 6 vol% sevoflurane and during wash-out from 6 to 0 vol% with fresh gas flows equal to 1 and 2 times the minute ventilation. The Avance was faster than the Primus (65 seconds [95% confidence interval (CI): 55 to 78] vs 310 seconds [95% CI: 261 to 359]) at 1.5 L/min fresh gas flow, tidal volume of 50 mL, and 30 breaths/min. Times were shorter by the same magnitude at higher fresh gas flows and higher minute ventilation rates. The effect of doubling fresh gas flow was variable and less than expected. The Primus is slower during newborn than toddler ventilation, whereas the Avance's response time was the same for newborn and toddler ventilation. Our data confirm that the time to reach the target-inspired anesthetic concentration depends on breathing circuit volume, fresh gas flow, and minute ventilation.

Impaired visual hand recognition in preoperative patients during brachial plexus anesthesia: importance of peripheral neural input for mental representation of the hand.

BACKGROUND: Perceptual illusions described in healthy subjects undergoing regional anesthesia (RA) are probably related to short-term plastic brain changes. We addressed whether performance on an implicit mental rotation task reflects these RA-induced changes in body schema brain representations. Studying these changes in healthy volunteers may shed light on normal function and the central mechanisms of pain. METHODS: Performance pattern was studied in upper limb-anesthetized subjects on a left/right hand judgment task, which is known to involve motor imagery processes relating to hand posture. Three conditions were used: control (i.e., absence of deafferentation), RA (i.e., deafferentation), and vision (i.e., deafferentated limb exposed to view). To limit potential bias such as order effect, the control state was recorded in a randomized manner. RESULTS: All subjects described perceptual illusions of their anesthetized limb. They were slower and less accurate on the task during RA compared with control. Response patterns were similar in all conditions, suggesting sensitivity of performance to arm/hand biomechanical constraints. Vision was associated with an increase in the proportion of correct responses and a reduction of the response times in hand judgment and was accompanied by disappearance of the lateralization of the underlying mental representations, which was identified during RA. CONCLUSIONS: These results suggest the following: (1) the right/left judgment task involves mental simulation of hand movements, (2) underlying mental representations and their neural substrates are subject to acute alterations after RA, and (3) the proprioceptive deficit induced by RA is influenced by the subject's ability to see the anesthetized limb.

Increased creatinine clearance in polytrauma patients with normal serum creatinine: a retrospective observational study.

INTRODUCTION: The aim of this study, performed in an intensive care unit (ICU) population with a normal serum creatinine, was to estimate urinary creatinine clearance (CLCR) in a population of polytrauma patients (PT) through a comparison with a population of non trauma patients (NPT). METHODS: This was a retrospective, observational study in a medical and surgical ICU in a university hospital. A total of 284 patients were consecutively included. Two different groups were studied: PT (n = 144) and NPT (n = 140). Within the second week after admission to the ICU, renal function was assessed using serum creatinine, 24 h urinary CLCR . RESULTS: Among the 106 patients with a CLCR above 120 mL minute(-1) 1.73 m(-2), 79 were PT and 27 NPT (P < 0.0001). Only 63 patients had a CLCR below 60 mL minute(-1) 1.73 m(-2) with 15 PT and 48 NPT (P < 0.0001). Patients with CLCR greater than 120 mL minute(-1). 1.73 m(-2) were younger, had a lower SAPS II score and a higher male ratio as compared to those having CLCR lower than 120 mL minute(-1). 1.73 m(-2). Through a logistic regression analysis, age and trauma were the only factors independently correlated to CLCR. CONCLUSIONS: In ICU patients with normal serum creatinine, CLCR, is higher in PT than in NPT. The measure of CLCR should be proposed as routine for PT patients in order to adjust dose regimen, especially for drugs with renal elimination.

Predictive value of abdominal obesity vs. body mass index for determining risk of intensive care unit mortality.

OBJECTIVE: To explore whether sagittal abdominal diameter as a marker of abdominal obesity is a risk factor for death and morbidity in patients in the intensive care unit and a better outcome determinant for obese patients than body mass index. DESIGN: Prospective, observational study from April 2008 to January 2009. SETTING: Two general intensive care units, both in Toulouse University Hospitals, France. PARTICIPANTS: All adult patients admitted in the two intensive care units except those routinely discharged within 48 hrs or those having conditions with possible effect on anthropometric indices. INTERVENTIONS: Measurement of the sagittal abdominal diameter at admission allowed us to divide the studied population into abdominally obese, underweight, and control groups. MEASUREMENTS AND RESULTS: The primary outcome measure was mortality in the intensive care unit until day 60 after admission. Secondary outcomes were morbidity and length of stay in the intensive care unit. Among 503 patients admitted, 403 were included. At admission, age, diabetes, dyslipidemia, hypertension, Simplified Acute Physiology Score II, and McCabe scores were higher in the abdominally obese group (n = 109) than in the control group (n = 277). The rate of death was higher in the abdominally obese group compared to control (44% vs. 25.3%; p < .01). After adjustment for age, simplified acute physiology score, II and McCabe score, a multivariate analysis showed an increased risk of death in the abdominally obese group (adjusted odds ratio, 2.12; 95% confidence interval, 1.25-3.60). A body mass index >30 kg/m2 was not an independent risk factor for death. During the stay in the intensive care unit, incidence of acute renal failure and abdominal compartment syndrome were higher in the abdominally obese group. CONCLUSION: A high sagittal abdominal diameter, and not a high body mass index, is an independent risk factor of death in critically ill patients.

Adverse drug reactions to local anaesthetics: a review of the French pharmacovigilance database.

BACKGROUND: Some evidence of significant patient morbidity or mortality has been reported with the use of local anaesthetics (LAs). The most common adverse drug reactions (ADRs) to LAs are neurological (seizures) and cardiac (conduction disorders, cardiac arrests). However, little is known about other adverse drug reactions (ADRs). OBJECTIVE: The aim of this study was to characterize the safety profile of the LAs lidocaine, bupivacaine, mepivacaine, ropivacaine and levobupivacaine. STUDY DESIGN: We studied ADRs occurring between 1995 and 2006 reported to the French Pharmacovigilance System. MAIN OUTCOME MEASURE: For each ADR, we noted type of LA, type of ADR, its seriousness and the causality assessment score. RESULTS: We identified 727 reports (corresponding to 0.3% of patients in the database) in which LA was suspected as the cause of 1157 different ADRs. Sixty-one patients (8.7%) were children aged<18 years. Lidocaine (36.0%) and bupivacaine (35.4%) were the LAs most often involved. The most frequently reported ADRs were failure of the block (27.7%), followed by neurological (22.1%), allergic (19.4%) and cardiovascular (15.3%) complications. Eight patients died. Spinal anaesthesia performed with bupivacaine represented 90% of failed blocks. Seizures were the most frequent neurological complications, leading to death in four cases. Twenty-two of 111 cardiovascular complications were cardiac arrest (three of which were fatal). CONCLUSION: To our knowledge, this is the first analysis of safety profiles of LAs in a non-selected population, using data collected in a pharmacovigilance database. The present study confirmed the frequency and seriousness of both neurological and cardiovascular complications. Other less well documented ADRs were identified, such as spinal anaesthesia failures with bupivacaine and allergic reactions following LA injections.

The efficacy of skin temperature for block assessment after infraclavicular brachial plexus block.

BACKGROUND: Although it has been reported that an increase in skin temperature indicates block success with higher specificity and sensibility than skin sensitivity to pinprick and cold, the methodology previously used computer-assisted infrared thermography, a technique that is expensive and requires substantial personnel training. In this prospective observational study, we evaluated whether a simple infrared thermometer can reliably predict block effectiveness after infraclavicular brachial plexus blockade. METHODS: Thirty consecutive patients undergoing upper limb surgery under infraclavicular block were enrolled. From the end of the local anesthetic injection, skin temperature was measured in all four major nerve distribution areas, and the sensory block onset (using cold and pinprick with 0 = no sensation to 2 = normal) were evaluated every 5 min for 30 min. A successful block was defined as the absence of sensation to cold (swab soaked with alcohol) and pinprick (needle) with a score of "0" within 30 min after the injection in the 4 major nerve distribution areas (radial, ulnar, median and musculocutaneous). Skin temperature measurements were performed using a noncontact temperature probe. RESULTS: One-hundred-twenty nerves (30 patients, 4 nerves per patient) were anesthetized. Twenty-five patients had a successful block. Four patients required supplementation for block failure. General anesthesia was performed in one patient. Skin temperature variation was not different among different nerves. There was a statistically significant increase in cutaneous temperature after nerve block compared to the same skin area before the procedure (P < 0.0001 from T5 to T30). Average temperature variations in blocked versus unblocked nerves at the same time were significantly different (P < 0.05 at T5 then P < 0.0001 from T10 to T30). When temperature in a specific sensory territory increased 1 degree C or more, at 5 and 10 min, the specific nerve was blocked (the score was "0"). Thus, when temperature changes in all 4 nerves were noted at 5 and 10 min, the block was successful at 30 min. No change in temperature in the contralateral arm or in the core temperature was observed. CONCLUSION: Skin temperature assessment with an infrared thermometer is a reliable, simple and early indicator of a successful nerve block.

Anaesthetic practices for scheduled caesarean delivery: a 2005 French national survey.

BACKGROUND AND OBJECTIVE: It is not known whether anaesthetic practices for ASA I parturients undergoing scheduled caesarean delivery have changed since the last (1996) survey and how practices reflect current recommendations. METHODS: A 26-item survey questionnaire (organization of the maternity unit, preoperative evaluation, technical aspects describing regional or general anaesthesia, oxytocic and antibiotic drugs, postoperative analgesia) was distributed to all French obstetric units (excluding overseas). RESULTS: The response rate was 73% (451/621). Preoperative evaluation included a recent platelet count in 97% of responding units, and information was given to patients in 84% of cases. Antibiotic prophylaxis in accordance with French guidelines was used in 78% of units. Anaesthetic techniques were single-shot spinal, epidural, combined spinal epidural and general anaesthesia in decreasing order (92.5, 4.5, 2 and 1%, respectively). Effervescent cimetidine was the first choice in 62% of units. Cricoid pressure and succinylcholine were routinely used in 66 and 77% of units, respectively. Oxytocin was used appropriately in 65% of units. In addition to spinal or epidural opioids, paracetamol, NSAIDs and nefopam were added postoperatively in 98, 68 and 19% of units, respectively. Poorer practices were found in units having a lower annual delivery rate. CONCLUSIONS: Overall practice was in accordance with national guidelines or practice patterns defined by the expert committee. Regional anaesthesia and postoperative analgesia-related techniques particularly were adequate. Some deficits were of limited importance (antibiotic prophylaxis and oxytocin administration), whereas others (use of succinylcholine and cricoid pressure) remain of concern.

Comparison of visual analogue scale and faces rating scale in measuring acute postoperative pain.

Several pain assessment tools have been proposed for use in different settings, but neither have been validated for all patients, especially Iranians. We conducted this study to compare the accuracy of two most commonly used tools for evaluation of pain intensity in a group of postoperative Iranian patients. All postoperative patients admitted to the surgical wards of Masih Daneshvari and Rasoul Akram Hospitals, Tehran, Iran were studied. During a two-month period, patients were evaluated for pain intensity within 24 hours of operation. Visual analogue scale and faces rating scale were used for this purpose. Eighty-two patients were enrolled into the study. Forty-eight patients underwent obstetrics and 34 had general surgeries. Using Spearman analysis, we found a linear correlation between the results of the two methods (P=0.952). Using multivariate analysis, we found that none of the variables such as age, gender, and education level had significant effects on correlation between visual analogue scale and faces rating scale. Visual analogue scale and faces rating scale are two pain assessment tools that can be used interchangeably for evaluation of acute postoperative pain.

Central venous-to-arterial carbon dioxide difference: an additional target for goal-directed therapy in septic shock?

OBJECTIVE: To test the hypothesis that, in resuscitated septic shock patients, central venous-to-arterial carbon dioxide difference [P(cv-a)CO(2)] may serve as a global index of tissue perfusion when the central venous oxygen saturation (ScvO(2)) goal value has already been reached. DESIGN: Prospective observational study. SETTING: A 22-bed intensive care unit (ICU). PATIENTS: After early resuscitation in the emergency unit, 50 consecutive septic shock patients with ScvO(2) > 70% were included immediately after their admission into the ICU (T0). Patients were separated in Low P(cv-a)CO(2) group (Low gap; n = 26) and High P(cv-a)CO(2) group (High gap; n = 24) according to a threshold of 6 mmHg at T0. MEASUREMENTS: Measurements were performed every 6 h over 12 h (T0, T6, T12). RESULTS: At T0, there was a significant difference between Low gap patients and High gap patients for cardiac index (CI) (4.3 +/- 1.6 vs. 2.7 +/- 0.8 l/min/m(2), P < 0.0001) but not for ScvO(2) values (78 +/- 5 vs. 75 +/- 5%, P = 0.07). From T0 to T12, the clearance of lactate was significantly larger for the Low gap group than for the High gap group (P < 0.05) as well as the decrease of SOFA score at T24 (P < 0.01). At T0, T6 and T12, CI and P(cv-a)CO(2) values were inversely correlated (P < 0.0001). CONCLUSION: In ICU-resuscitated patients, targeting only ScvO(2) may not be sufficient to guide therapy. When the 70% ScvO(2) goal-value is reached, the presence of a P(cv-a)CO(2) larger than 6 mmHg might be a useful tool to identify patients who still remain inadequately resuscitated.

Postoperative analgesia after total hip arthroplasty: patient-controlled analgesia versus transdermal fentanyl patch.

STUDY OBJECTIVE: To determine whether a new transdermal fentanyl patch (TFP) is a good choice for the postoperative pain management of patients undergoing primary total hip arthroplasty compared with patient-controlled analgesia (PCA). DESIGN: Randomized, prospective study. SETTING: University hospital. PATIENTS: 30 patients undergoing primary total hip arthroplasty. INTERVENTIONS: Patients received either a TFP (group T; Duragesic 50 microg/h, matrix fentanyl patch, Janssen-Cilag) applied approximately 10 hours before induction of general anesthesia and PCA programmed in the postanesthesia care unit (PACU), or PCA programmed in the PACU (group P). MEASUREMENTS: Intraoperative sufentanil and additional postoperative morphine administration were recorded, as well as visual analog scores and routine vital signs at predetermined intervals during the first 48 hours. MAIN RESULTS: Morphine consumption on arrival in the PACU was 3.5+/-3 mg in group T versus 13+/-5 mg in group P (P<0.0001). Visual analog scores on arrival in the PACU were 37+/-22 mm in group T versus 73+/-13 mm in group P (P<0.0001). Cumulative morphine consumption at the 24th hour was 43+/-16 mg in group P and 4+/-3 mg in group T (P<0.0001). Cumulative morphine consumption at the 48th hour was 54+/-26 mg in group P and 5+/-4 mg in group T (P<0.0001). Intraoperative sufentanil consumption was 38+/-15 microg in group T versus 30+/-5 microg in group P (not significant). The sedation score was 0 in both groups during the first 48 postoperative hours. CONCLUSIONS: Preoperative TFP application decreases pain scores and morphine consumption in the PACU and appears to have prolonged effects spanning the first 48 postoperative hours.

Modifications of low-molecular weight heparin use in a French university hospital after implementation of new guidelines.

BACKGROUND: Previous studies performed in 1999 and 2000 showed frequent misuse of low-molecular weight heparins (LMWHs) in France, leading to an increasing risk of bleeding. In 2002, the French Medicine Agency (Agence Française de Sécurité Sanitaire des Produits de Santé) released guidelines on the prescription and monitoring of LMWH. This study assesses LMWH use before and after the implementation of these guidelines. METHODS: We performed a 'pre and post' survey comparing data collected in 1999 (before guidelines) and in 2003 (1 year after guidelines) at a French university hospital. The same design and the same medical wards were used for both data-collection periods, and the data collected included patient characteristics, LWMH prescription information (daily dose, indication) and adverse drug reactions (ADRs). The main outcome was the frequency of prescription of LMWHs for curative treatment in patients with severe renal insufficiency, defined as having a creatinine clearance of

Morphine in postoperative patients: pharmacokinetics and pharmacodynamics of metabolites.

BACKGROUND: There is great variability in the need for morphine in the postoperative period. We performed a pharmacokinetic-pharmacodynamic study considering the potential effect of the two main metabolites of morphine. METHODS: Fifty patients with moderate to severe pain received morphine as an IV titration, followed by IM administration postoperatively. The plasma concentration of morphine, morphine-6-glucuronide (M-6-G), morphine-3-glucuronide (M-3-G), and pain intensity were measured at frequent intervals. Pharmacokinetic and pharmacodynamic fitting was performed with the software NONMEM. RESULTS: The pharmacokinetics were largely predictable. M-6-G and M-3-G clearances were markedly decreased in patients with renal failure. The pharmacodynamics was less predictable, with an important interindividual variability. M-6-G was 7.8 times more potent than morphine, but the average time to peak concentration in the effect compartment after a bolus injection of morphine was 4.25 h for M-6-G, when compared to 0.33 h for morphine. M-3-G showed mild inhibition of the analgesic properties of morphine and of M-6-G. The time to M-3-G peak concentration in the effect compartment after a bolus injection of morphine was 10 h. CONCLUSIONS: M-6-G is a potent opioid agonist and M-3-G a mild opioid antagonist. Both are poorly excreted in patients with renal failure. However, the metabolism of morphine was rapid when compared to the transfer of metabolites through the blood-brain barrier, which appears to be the limiting process. Because poor analgesia due to M-3-G's effect may occur in some patients after 1 or 2 days, a switch to other molecules should be considered.

The paramedian technique: a superior initial approach to continuous spinal anesthesia in the elderly.

BACKGROUND: Spinal anesthesia in elderly patients is frequently associated with significant technical difficulties. Thus, we compared the classical midline approach to the paramedian approach to perform continuous spinal anesthesia (CSA). METHODS: We prospectively studied 40 patients aged >75 yr who underwent open surgical repair of a hip fracture. These patients were randomly allocated to one of two groups: Group M: midline approach, and Group PM: paramedian approach. Patients were positioned in the lateral decubitus to receive CSA at L4-5 level. CSA was considered successful if cerebrospinal fluid was obtained through the needle. In case of initial failure in either approach, the same approach was repeated by the same operator. If two attempts were unsuccessful, the other anatomical approach was used by the same operator. If both approaches failed, a staff anesthesiologist performed a final attempt. In case of failure or insufficient block, the patient received general anesthesia. RESULTS: The success rate after the first attempt was 85% (17) for Group PM and 45% (9) for Group M (P = 0.02). All catheters were successfully introduced. No patient required general anesthesia. Vascular puncture after needle puncture was observed in six patients in Group M versus 0 in Group PM (P = 0.03), but none were of clinical consequence. No other clinically significant complications were observed. CONCLUSION: In summary, after the initial attempt, the paramedian approach is associated with an increased success rate, compared with the midline approach, during the performance of CSA in elderly patients.

Eutectic mixture of local anesthetic (EMLA) decreases pain during humeral block placement in nonsedated patients.

BACKGROUND: We evaluated the potential role of an euctectic mixture of local anesthetic (EMLA) cream application before performing midhumeral block. METHODS: Sixty patients undergoing surgery distal to the elbow amenable to a humeral block were prospectively recruited for the study. The patients were randomly allocated to 1 of 3 groups: Group E: topical EMLA cream 60 min before block plus 2 mL IV normal saline 5 min before procedure; Group P: topical sham cream plus 2 mL IV normal saline, and Group S: topical sham cream plus 0.1 microg/kg of sufentanil in 2 mL solution IV. Pain experienced during skin puncture, and overall pain for the whole procedure were rated using a 100-mm visual analog scale (0: no pain to 100: worst pain). RESULTS: Patients in Group E experienced less pain compared with those in Groups P and S (5 +/- 3 mm vs 33 +/- 20 mm and 30 +/- 18 mm, respectively, P < 0.0001). The pain experienced throughout the complete humeral block was more substantial in Group P than in Group E (P = 0.01). CONCLUSION: The patients who received EMLA cream had less pain with needle puncture as well as throughout the performance of humeral block.

The optimal motor response for infraclavicular brachial plexus block.

BACKGROUND: In this prospective study we compared the success of the infraclavicular brachial plexus block using double-stimulation in regard to the second nerve response elicited with neurostimulation. METHODS: Six-hundred-twenty-eight patients undergoing emergency upper limb surgery using infraclavicular brachial plexus block were included in this study. The musculocutaneous nerve was initially blocked and the groups were then evaluated according to the second nerve located, which was radial in 54%, median in 35%, and ulnar in 11% of patients. Blocks were performed using lidocaine 1.5% with 1/400,000 epinephrine 40 mL in all cases. The block was assessed every 5 min for 30 min after completion of the block. RESULTS: The success rate was 96% for the radial response group, 89% for the median response group, and 90% for the ulnar response group (P < 0.05). Time to perform the block and the onset time were not significantly different among groups. No serious complications were observed. CONCLUSION: We conclude that having initially located and blocked the musculocutaneous nerve, subsequent injection on a radial response resulted in a slightly more reliable success rate than injection with an ulnar or median response.

The hemodynamic "target": a visual tool of goal-directed therapy for septic patients.

OBJECTIVE: To improve understanding of the hemodynamic status of patients with sepsis by nursing teams through the attainment of hemodynamic parameters using a pentaxial "target" diagram as a clinical tool. Parameters include cardiac index (CI), arterial oxygen saturation (SaO2), mean arterial pressure (MAP), arterial blood lactate, and central venous oxygen saturation (ScvO2). DESIGN: Prospective descriptive study. SETTING: The intensive care unit of a university hospital. PATIENTS: During a 6-month period, 38 intubated septic shock patients were included in the study. Survivors and nonsurvivors were compared. INTERVENTIONS: MAP, CI, SaO2, ScvO2 and lactate were measured at 0, 6, 12, 24, 36, and 48 h. Measurements were recorded on the target diagram along with the norepinephrine infusion rate and the hemoglobin (Hb) level. The number of lactate and ScvO2 measurements achieved during the target period were compared to a 6-month retrospective control period just before starting the protocol. We assessed the nurse knowledge status prior to the introduction of target diagram. We then performed a post-test after implementing the new recording technique. MEASUREMENTS AND RESULTS: The nursing team expressed a positive attitude toward the target concept. The mean number of lactate and ScvO2 measurements performed for each patient during the control period was significantly lower than during the target period, and those values were rarely used as goal values before the introduction of the target diagram. At 24 hours, 46% of the survivors had achieved all the goal parameter values of the target diagram, compared to only 10% of nonsurvivors (P = .01). CONCLUSION: The target diagram is a visual multiparametric tool involving all the medical and nursing team that helps achieve goal-directed therapy for septic patients. The number of goal values reached at each time point during the first 48 hours was closely linked to mortality.

Clinical profile, contemporary management and one-year mortality in patients with severe acute heart failure syndromes: The EFICA study.

BACKGROUND: Little is known about the epidemiology of acute decompensated heart failure (ADHF) in patients admitted to intensive and coronary care units (ICU/CCU). Observational data may improve disease management and guide the design of clinical trials. AIMS: EFICA is an observational study of the clinical profile, management and survival of ADHF patients admitted to ICU/CCU. METHODS: The study included 599 patients admitted to 60 ICU/CCUs across France. Relevant data was recorded during hospitalisation. Survival was assessed at 4 weeks and 1 year. RESULTS: The main cause of ADHF was ischaemic heart disease (61%); 29% of patients had cardiogenic shock. Mortality was 27.4% at 4 weeks and 46.5% at 1 year, increasing to 43.2% and 62.5%, respectively, when including pre-admission deaths. Shock patients had the highest [57.8% vs. 15.2% without shock (p < 0.001)] and patients with hypertension and pulmonary oedema had the lowest 4-week mortality: (7%). Pre-admission NYHA class III-IV heart failure, not initial clinical presentation, influenced 1-year mortality. CONCLUSION: ADHF is a heterogeneous syndrome. Based on initial clinical presentation, three entities with distinct features and outcome may be described: cardiogenic shock, pulmonary oedema with hypertension, and 'decompensated' chronic heart failure. This should be taken into account in future observational studies, guidelines and clinical trials.

Influence of renal function on trough serum concentrations of piperacillin in intensive care unit patients.

OBJECTIVE: To explore the effects of renal function estimated by measured creatinine clearance (Cl(CR)) on trough serum concentration (C(min)) of piperacillin given to critically ill patients. DESIGN: Prospective observational study. SETTING: An intensive care unit and research ward in a university hospital. PATIENTS: Seventy critically ill patients, including 22 with severe trauma. INTERVENTIONS: All subjects received an intravenous infusion of piperacillin 4 g three times (n = 61) or four times (n = 9) per day. Piperacillin C(min) values were determined 24 h after treatment started and compared to the French breakpoint defining antibiotic susceptibility against Enterobacteriaceae (8 mg/l) or Pseudomonas sp. (16 mg/l). RESULTS: Median (range) piperacillin C(min) was 11.9 (< 1-156.3) mg/l, with a great variability among patients. Although the median value was close to the breakpoints, sub-therapeutic plasma levels were frequently observed. Piperacillin C(min) was lower than the breakpoint for Enterobacteriaceae in 37% of patients, and lower than the breakpoint for P. aeruginosa in 67% of them. A strong relationship was observed between piperacillin C(min) and Cl(CR): the higher the Cl(CR,) the lower the piperacillin C(min )in serum. For patients with a Cl(CR) < 50 ml/min, enough piperacillin C(min) was achieved in most patients with 12 g piperacillin per day. For patients with higher Cl(CR) values, a piperacillin daily dose of 16 g or more may be warranted. CONCLUSIONS: In critically ill patients, therapeutic monitoring must be part of the routine, and knowledge of Cl(CR) value may be useful for the choice of adequate initial piperacillin dosing.

Spinal anesthesia using single injection small-dose bupivacaine versus continuous catheter injection techniques for surgical repair of hip fracture in elderly patients.

Aging and disease may make elderly patients particularly susceptible to hypotension during spinal anesthesia. We compared the hemodynamic effect of continuous spinal anesthesia (CSA) and small dose single injection spinal anesthesia (SA) regarding the incidence of hypotension. Seventy-four patients aged >75 yr undergoing surgical repair of hip fracture were randomized into 2 groups of 37 patients each. Group CSA received a continuous spinal anesthetic with a titration of 2.5 mg boluses every 15 min of isobaric bupivacaine, while group SA received a single injection spinal anesthetic with 7.5 mg of isobaric bupivacaine. The overall variations in noninvasive automated arterial blood pressure were not statistically significantly different in the 2 groups at baseline and after CSA or SA (not significant). In the SA group, 68% of patients experienced at least one episode of hypotension (decrease in systolic arterial blood pressure greater than 20% of baseline value) versus 31% of patients in the CSA group (P = 0.005). In the SA group, 51% of patients experienced at least one episode of severe hypotension (decrease in systolic arterial blood pressure more than 30% of baseline value) versus 8% of patients in the CSA group (P < 0.0001). In the CSA group, 4.5 +/- 2 mg of ephedrine was injected versus 11 +/- 2 mg in the SA group (P = 0.005). In the CSA group, 5 mg (2.5-10) of anesthetic solution was required versus 7.5 mg in the SA group (P < 0.0001). We conclude that, in elderly patients undergoing hip fracture repair, CSA provides fewer episodes of hypotension and severe hypotension compared with a single intrathecal injection of 7.5 mg bupivacaine.

Stroke output variations calculated by esophageal Doppler is a reliable predictor of fluid response.

OBJECTIVE: Esophageal Doppler allows continuous monitoring of stroke volume index (SVI) and corrected flow time (FTc). We hypothesized that variations in stroke output index SOI (SVI/FTc) during volume expansion can predict the hemodynamic response to subsequent fluid loading better than the static values. DESIGN AND SETTING: Prospective study in the intensive care unit of a university hospital. PATIENTS: Fifty-one patients with circulatory failure were monitored by esophageal Doppler. INTERVENTIONS: Patients who responded to a first fluid challenge received a second one. Patients who responded to both were classified as responders-responders, and those who did not respond to the second as responders-nonresponders. In these two groups we compared DeltaSVI, DeltaFTc, and DeltaSOI during each fluid challenge and also static values at the end of each fluid challenge. MEASUREMENTS AND RESULTS: After the first fluid challenge DeltaSOI and DeltaSVI were significantly higher in patients who responded to subsequent volume expansion than in patients who no longer responded. ROC curves showed that DeltaSOI was a better predictor of fluid responsiveness than DeltaSVI. During volume expansion a DeltaSOI value of 11% discriminated between responders and nonresponders to subsequent volume expansion with a sensitivity of 91% and a specificity of 97%. There was no significant difference between the two groups for FTc value at the end of first fluid challenge. CONCLUSIONS: Analysis of DeltaSOI during fluid challenge predicts response to subsequent fluid challenge and FTc is not a reliable indicator of cardiac preload.