Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2002
Comparative Study Clinical TrialPreload index: pulmonary artery occlusion pressure versus intrathoracic blood volume monitoring during lung transplantation.
In this study, during lung transplantation, we analyzed a conventional preload index, the pulmonary artery occlusion pressure (PAOP), and a new preload index, the intrathoracic blood volume index (ITBVI), derived from the single-indicator transpulmonary dilution technique (PiCCO System), with respect to stroke volume index (SVIpa). We also evaluated the relationships between changes (Delta) in ITBVI and PAOP and DeltaSVIpa during lung transplantation. The reproducibility and precision of all cardiac index measurements obtained with the transpulmonary single-indicator dilution technique (CIart) and with the pulmonary artery thermodilution technique (CIpa) were also determined. Measurements were made in 50 patients monitored with a pulmonary artery catheter and with a PiCCO System at six stages throughout the study. Changes in the variables were calculated by subtracting the first from the second measurement (Delta(1)) and so on (Delta(1) to Delta(5)). The linear correlation between ITBVI and SVIpa was significant (r(2)=0.41; P < 0.0001), whereas PAOP poorly correlated with SVIpa (r(2) = -0.01). Changes in ITBVI correlated with changes in SVIpa (Delta(1), r(2) = 0.30; Delta(2), r(2) = 0.57; Delta(4), r(2) = 0.26; and Delta(5), r(2) = 0.67), whereas PAOP failed. The mean bias between CIart and CIpa was 0.15 l. min(-1). m(-2) (1.37). In conclusion, ITBVI is a valid indicator of cardiac preload and may be superior to PAOP in patients undergoing lung transplantation. ⋯ The assessment of intrathoracic blood volume index (ITBVI) by the transpulmonary single-indicator technique is a useful tool in lung transplant patients, providing a valid index of cardiac preload that may be superior to pulmonary artery occlusion pressure. However, more prospective, randomized studies are necessary to evaluate the role and limitations of this technique.
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Anesthesia and analgesia · Oct 2002
Comparative Study Clinical TrialA comparison between anterior and posterior monitoring of neuromuscular blockade at the diaphragm: both sites can be used interchangeably.
We present a novel site of monitoring neuromuscular blockade of the diaphragm at the patient's back. After the induction of anesthesia, 12 patients were orotracheally intubated. Two Ag/AgCl-electrodes were attached at the right seventh or eighth intercostal space between the midclavicular and anterior axillary line; two Ag/AgCl-electrodes were paravertebrally attached on the right side lateral to vertebrae T12-L1 or L1-2. Two Ag/AgCl-skin-electrodes were placed over the right thenar area for an electromyography recording of the adductor pollicis (AP) muscle, and two Ag/AgCl-skin-electrodes were used to stimulate the ulnar nerve. Onset and offset of neuromuscular blockade after rocuronium 0.6 mg/kg were determined, and significant differences between diaphragm and AP muscle and agreement between the two methods were determined. Mean maximum block was more than 96% at all sites. Lag time, onset 50, and onset time were not significantly different between the diaphragm and the AP. However, time to reach 25% of control twitch was significantly longer at the AP muscle than at the diaphragm (P < 0.001). The difference of the means and limits of agreement between the anterior and the posterior site of diaphragmatic monitoring were 0 +/- 11 s, 3 +/- 9 s, 0 +/- 19 s, and -2% +/- 5% for lag, onset 50, onset time, and peak effect, respectively, and -2 +/- 2 min for the time to reach 25% of control twitch of neuromuscular blockade. We conclude that anterior and posterior diaphragmatic monitoring can be used interchangeably to determine neuromuscular blockade after rocuronium. ⋯ We present a novel site of monitoring neuromuscular blockade of the diaphragm at the patient's back, which shows good agreement with the conventional anterior site at the seventh or eighth intercostal space.
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Anesthesia and analgesia · Oct 2002
Clinical TrialIn vitro fertilization-induced alterations in coagulation and fibrinolysis as measured by thromboelastography.
Supraphysiologic increases in estrogen produced by in vitro fertilization (IVF) promote the expression of hemostatic markers. Although quantitative studies of individual markers have been performed during IVF, their results are conflicting and do not reveal the qualitative effect of each marker on the overall coagulation and fibrinolytic processes. Thrombelastograph (TEG) coagulation analysis, by contrast, provides a global measure of coagulation and fibrinolysis and can indicate the relative contributions of clotting factors, fibrinogen, and platelets to each process. ⋯ Thrombelastograph coagulation analysis, which provides a global assessment of these changes, demonstrated significant alterations in two coagulation indices (clot formation time, coagulation index), although all variables remained within normal limits. The relative importance of fibrinogen versus platelets in determining clot strength was observed. No significant alterations in fibrinolysis were detected.
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Anesthesia and analgesia · Oct 2002
Clinical TrialPersistent pain after cardiac surgery: an audit of high thoracic epidural and primary opioid analgesia therapies.
Persistent pain is an underreported morbidity after cardiac surgery. We sent pain surveys to all patients who underwent coronary artery bypass graft surgery from 1997 to 1999 from a single surgeon's experience. Two analgesia strategies were used: high thoracic epidural (HTEA) or IV and oral opiates (OPIOID) for 48-72 h after surgery. Persistent pain was defined as pain still present two or more months after surgery, and all questions referred to the time of survey only. From 356 questionnaires, 305 patients responded, and 61 of them refused consent, leaving 244 patients with complete surveys (HTEA, 150 patients [69%]; OPIOID, 94 patients [68%]). The incidence of persistent pain at any site was 29% and for sternotomy was 25%. The intensity of pain reported was mild, with only 7% reporting interference with daily living. Other common locations of persistent pain were the shoulders (17.4%), back (15.9%), and neck (5.8%). Twenty patients (8%) described symptoms suggestive of the internal mammary artery syndrome. A comparative audit of the HTEA and OPIOID groups showed no significant differences in the frequency or intensity of pain, although the time of survey from operation was longer in the OPIOID group. Mild persistent chest pain after sternotomy is common but infrequently interferes with daily life. ⋯ Persistent wound pain after coronary artery bypass surgery is common, but it is usually is mild and infrequently interferes with daily living. An audit of two pain relief strategies (epidural analgesia or opiate analgesia) did not show any difference in the incidence of persistent pain.
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Anesthesia and analgesia · Oct 2002
Hemodilution with albumin, but not Hextend, results in hypercoagulability as assessed by Thrombelastography in rabbits: role of heparin-dependent serpins and factor VIII complex.
Isovolemic hemodilution (IVHD) has been advocated as an effective method of reducing the need for transfusion but has been associated with hypercoagulability. We tested the hypothesis that IVHD enhances hemostatic function by decreasing circulating antithrombin activity in rabbits. Furthermore, it was determined whether different replacement solutions would affect hemostasis. Sedated rabbits were randomly assigned to groups that underwent IVHD (40% blood volume removed) with 5% human albumin (n = 10) or a 6% hetastarch solution (Hextend). Antithrombin and Factor VIII complex (VIII:C) activities were determined, and thrombelastography(R) was performed with or without platelet inhibition. IVHD resulted in a significant (P < 0.05) decrease in antithrombin (32%-39%) without fluid-specific differences observed. VIII:C did not change in the albumin group, whereas the hetastarch group had a significant (P < 0.05) decrease (43%) in VIII:C that was also significantly (P < 0.05) less than the albumin group. The time to clot initiation was decreased, and the rate of clot formation increased significantly via thrombelastography(R) in albumin animals. No significant change in clot kinetics was observed in hetastarch animals. In rabbits, the primary determinant of hemostasis after IVHD was the interaction of changes in antithrombin activity and VIII:C. These data serve as a rational basis to determine whether IVHD-mediated hypercoagulability encountered clinically may be attenuated or exacerbated by the choice of colloid administered. ⋯ Isovolemic hemodilution (IVHD) is associated with hypercoagulability. Rabbits hemodiluted with albumin, but not Hextend, became hypercoagulable secondary to a loss of antithrombin activity with simultaneous maintenance of Factor VIII complex activity (VIII:C). Hextend-treated animals had proportionate decreases in both antithrombin activity and VIII:C. IVHD-mediated hypercoagulability encountered clinically may be attenuated or exacerbated by the choice of colloid administered.