Cardiac index validation using the pressure recording analytic method in unstable patients.

OBJECTIVE: The authors investigated the accuracy and precision of the pressure recording analytic method (PRAM) in cardiac index measurement compared with thermodilution in unstable patients, a setting in which minimally invasive monitoring devices often fail. DESIGN: Criterion standard. SETTING: Intensive care unit. PATIENTS: Thirty-two consecutive patients with low cardiac output syndrome treated with an intra-aortic balloon pump and/or high doses of inotropic drugs but without atrial fibrillation were studied after cardiac surgery. INTERVENTIONS: None. Pulmonary and radial artery catheters were already in situ for clinical reasons. MEASUREMENTS AND MAIN RESULTS: Four patients (12.5%) were excluded from the study because of artifacts caused by under- or overdamping of the arterial pressure monitoring system. The authors performed 3 injections of the thermal indicator in 5 minutes through the pulmonary artery catheter. Mean cardiac index values of 12 consecutive beats were considered for the PRAM. A significant correlation was found between the cardiac index assessed by thermodilution and PRAM (r = 0.72, p < 0.001). The mean bias between the 2 techniques was 0.072 +/- 0.41 L/min/m(2) with lower and upper 95% limits of confidence of -0.089 and 0.233 L/min/m(2), respectively. The percentage error was 30%. Sufficient agreement between the two techniques was evidenced by the Bland-Altman plot with only two points above the limits of agreement. CONCLUSIONS: This study showed that PRAM, a minimally invasive method for cardiac index assessment, is clinically useful even in unstable patients such as those receiving intra-aortic balloon pump and/or ongoing high doses of a inotropic drugs because of a low cardiac output syndrome but without atrial fibrillation.

How to explain a PaO2 of 140 mmHg in a venous line?

Metformin is a commonly used oral antidiabetic drug which can cause lactic acidosis. Although rare, this condition carries a high mortality risk. Correction of metabolic acidaemia is essential for treatment and dialysis with bicarbonate replacement is the gold standard approach. A 53-year-old man with diabetes on metformin therapy was admitted to the intensive care unit with severe lactic acidosis and acute renal failure suggesting metformin intoxication. The lactic acidosis was treated with bicarbonate haemodialysis and his pH normalized after 10 hours, but he died because of myocardial infarction due to severe hypotension. At ICU admission an aortic dissection was also hypothesized but TEE did not evidence aortic dissection. The dilemma in this patient was represented by the abnormal PaO2 value (140 mmHg) in the venous blood gas analysis. Considering that metformin acts on mitochondrial respiration, the dilemma may be explained by hypothesizing a cellular respiration block caused by metformin or severe acidosis. (www.actabiomedica.it)

Desmopressin reduces transfusion needs after surgery: a meta-analysis of randomized clinical trials.

BACKGROUND: Perioperative pathologic microvascular bleeding is associated with increased morbidity and mortality and could be reduced by hemostatic drugs. At the same time, safety concerns regarding existing hemostatic agents include excess mortality. Numerous trials investigating desmopressin have lacked power to detect a beneficial effect on transfusion of blood products. The authors performed a meta-analysis of 38 randomized, placebo-controlled trials (2,488 patients) investigating desmopressin in surgery and indicating at least perioperative blood loss or transfusion of blood products. METHODS: Pertinent studies were searched in BioMed Central, CENTRAL, and PubMed (updated May 1, 2008). Further hand or computerized searches involved recent (2003-2008) conference proceedings. RESULTS: In most of the included studies, 0.3 microg/kg desmopressin was used prophylactically over a 15- to 30-min period. In comparison with placebo, desmopressin was associated with reduced requirements of blood product transfusion (standardized mean difference = -0.29 [-0.52 to -0.06] units per patient; P = 0.01), which were more pronounced in the subgroup of noncardiac surgery and were without a statistically significant increase in thromboembolic adverse events (57/1,002 = 5.7% in the desmopressin group vs. 45/979 = 4.6% in the placebo group; P = 0.3). CONCLUSIONS: Desmopressin slightly reduced blood loss (almost 80 ml per patient) and transfusion requirements (almost 0.3 units per patient) in surgical patients, without reduction in the proportion of patients who received transfusions. This meta-analysis suggests the importance of further large, randomized controlled studies using desmopressin in patients with or at risk of perioperative pathologic microvascular bleeding.

Thiopental is better than propofol for electroconvulsive therapy.

BACKGROUND AND AIM OF THE WORK: electroconvulsive therapy is a psychiatric procedure requiring general anesthesia. The choice of the hypnotic agent is important because the success of the intervention is associated to the occurrence and duration of motor convulsion. However, all available anesthetic agents have anti-convulsant activity. We compared the effect of thiopental and propofol on seizures. METHODS: We designed a retrospective study at Mood Disorders Unit of a teaching Hospital. Fifty-six consecutive patients undergoing electroconvulsive therapy were enrolled. Patients received fentanyl followed by either thiopental or propofol. We evaluated the incidence and the duration of seizure after electric stimulus at the first session of electroconvulsive therapy for each patient. Adverse perioperative effects were recorded. RESULTS: Patients were 60±12.1 years old and 64% was female. There was a statistically significant higher number of patients who had motor convulsion activity in the thiopental group when compared to the propofol group (25 vs 13, p=0.023). Seizure duration was statistically significant longer in the thiopental group than in the propofol group (35 sec vs 11 sec, p=0.046). No hemodynamic instability, oxygen desaturation episodes, prolonged recovery time from anesthesia and adverse effects related to anesthesia were recorded. CONCLUSIONS: Thiopental induction has a favourable effect on seizure when compared to propofol in patients undergoing electroconvulsive therapy.

Spinal ropivacaine or bupivacaine for cesarean delivery: a prospective, randomized, double-blind comparison.

BACKGROUND AND OBJECTIVES: The aim of this prospective, randomized, double-blinded study was to compare clinical efficacy and safety of ropivacaine and bupivacaine given intrathecally in combination with morphine for cesarean delivery. METHODS: With ethical committee approval and a written informed consent, 60 women scheduled for elective cesarean delivery under spinal anesthesia were randomly allocated to receive spinal anesthesia with either 20 mg ropivacaine plus 0.1 mg morphine (n = 30) or 15 mg bupivacaine plus 0.1 mg morphine (n = 30). Profile of spinal block (onset and recovery times), cardiovascular effects, and quality of postoperative analgesia (patient-controlled morphine) were recorded by a blinded observer. RESULTS: The onset time of motor block was shorter after bupivacaine (8 +/- 2 min) than after ropivacaine (12 +/- 5 minutes) (P <.05), whereas duration of both sensory and motor blocks was longer after bupivacaine (139 +/- 37 minutes and 254 +/- 76 minutes) than after ropivacaine (112 +/- 27 minutes and 211 +/- 48 minutes) (P <.01 and P <.05, respectively). No differences in intraoperative quality of anesthesia and clinical hypotension requiring ephedrine administration were observed between the two groups. Postoperative analgesia was similarly effective in both groups; however median consumption of patient-controlled morphine during the first 24 hours after surgery was higher in patients of group Ropivacaine (5 mg; range, 0 to 18 mg) than in patients of group Bupivacaine (2 mg; range, 0 to 7 mg) (P <.01). CONCLUSION: Spinal anesthesia produced with 20 mg ropivacaine plus 0.1 mg morphine is as effective and safe as that provided by 15 mg bupivacaine plus 0.1 mg morphine, with an earlier recovery of sensory and motor functions after surgery.

Miniaturized cardiopulmonary bypass improves short-term outcome in cardiac surgery: a meta-analysis of randomized controlled studies.

OBJECTIVE: To investigate whether the use of miniaturized cardiopulmonary bypass translates into decreased morbidity and mortality in patients having cardiac surgery. METHODS: We independently conducted a systematic review and meta-analysis of data pooled from existing trials listed in PubMed and conference proceedings. Sixteen studies were identified, including 1619 patients having cardiac surgery. Inclusion criteria were random allocation to treatment and comparison of a miniaturized cardiopulmonary bypass system versus conventional cardiac surgery. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no outcome data. The end points were the rate of neurologic and myocardial damage and the number of patients transfused. RESULTS: Miniaturized cardiopulmonary bypass was associated with significant reductions of neurologic damage (4/548 [0.7%] vs 19/555 [3.4%], odds ratio = 0.30 [0.12-0.73], P = .008), reduction in peak cardiac troponin (weighted mean difference = -0.15 ng/dL [-0.18, -0.11], P < .001), and in the number of transfused patients (55/552 [9.9%] vs 101/563 [17.9%], odds ratio = 0.42 [0.28-0.63], P < .001). No difference in mortality was noted (8/758 [1.0%] vs 14/771 [1.8%], odds ratio = 0.60 [0.26-1.39]). CONCLUSIONS: Miniaturized cardiopulmonary bypass has beneficial effects resulting in decreased transfusion rate and cardiac and neurologic damage.

Monitoring cerebral oxygen saturation in elderly patients undergoing general abdominal surgery: a prospective cohort study.

BACKGROUND AND OBJECTIVES: The aim of this prospective, observational study was to evaluate changes in regional cerebral oxygen saturation (rSO2) and incidence of intraoperative cerebral desaturation in a cohort of elderly patients undergoing major abdominal surgery. METHODS: rSO2 was continuously monitored on the left and right sides of the forehead in 60 patients older than 65 yr (35 males and 25 females; ASA II-III; age: 72 +/- 5 yr; without pre-existing cerebral pathology, and baseline Mini Mental State Examination (MMSE) score >23) undergoing sevoflurane anaesthesia for major abdominal, non-vascular surgery >2 h. RESULTS: Baseline rSO2 was 63 +/- 8%; cerebral desaturation (rSO2 decrease <75% of baseline or <80% in case of baseline rSO2 <50%) occurred in 16 patients (26%). The MMSE decreased from 28 +/- 1 before surgery to 27 +/- 2 on 7th postoperative day (P = 0.05). A decline in cognitive function (decrease in MMSE score > or = 2 points one week after surgery as compared to baseline value) was observed in six patients without intraoperative cerebral desaturation (13.6%) and six patients who had intraoperative cerebral desaturation (40%) (P = 0.057) (odds ratio: 4.22; CI95%: 1.1-16). Median (range) hospital stay was 14 (5-41) days in patients with an area under the curve of rSO2 <50% (AUCrSO2<50%) >10 min%, and 10 (4-30) days in those with an AUCrSO2<50% <10 min% (P = 0.0005). CONCLUSIONS: In a population of healthy elderly patients, undergoing non-vascular abdominal surgery cerebral desaturation can occur in up to one in every four patients, and the occurrence of cerebral desaturation is associated with a higher incidence of early postoperative cognitive decline and longer hospital stay.

Spinal anesthesia with hyperbaric levobupivacaine and ropivacaine for outpatient knee arthroscopy: a prospective, randomized, double-blind study.

To compare unilateral spinal block produced with small doses of hyperbaric ropivacaine with that produced by 2 doses of hyperbaric levobupivacaine, we randomly allocated 91 ASA physical status I-II outpatients undergoing knee arthroscopy to receive unilateral spinal anesthesia with 7.5 mg of hyperbaric ropivacaine 0.5% (group Ropi-7.5, n = 31) or either 7.5 mg (group Levo-7.5, n = 30) or 5 mg (group Levo-5, n = 30) of hyperbaric levobupivacaine 0.5%. Spinal anesthesia was performed at the L3-4 interspace using a 25-gauge Whitacre spinal needle. The lateral decubitus position was maintained for 15 min after injection. Strictly unilateral sensory block was present in 73%, 50%, and 61% of cases in groups Ropi-7.5, Levo-7.5, and Levo-5, respectively, 30 min after injection (P = 0.40), and unilateral motor block was observed in 94%, 93%, and 83% in groups Ropi-7.5, Levo-7.5, and Levo-5, respectively (P = 0.31). One patient of group Ropi-7.5 required general anesthesia to complete surgery, and fentanyl supplementation was required in one patient of group Ropi-7.5 (3%) and one patient of group Levo-5 (3%) (P = 0.42). The median (range) time for spinal block resolution was shorter in group Ropi-7.5 (135 [126-154] min] than in group Levo-7.5 (162 [148-201] min) (P = 0.04); whereas home discharge was shorter in groups Ropi-7.5 (197 [177-218] min) and Levo-5 (197 [187-251] min) as compared with group Levo-7.5 (238 [219-277] min) (P = 0.02 and P = 0.04, respectively). We conclude that 7.5 mg of 0.5% hyperbaric ropivacaine and 5 mg of 0.5% hyperbaric levobupivacaine provide adequate spinal block for outpatient knee arthroscopy, with a faster home discharge as compared with 7.5 mg of 0.5% hyperbaric levobupivacaine.