PubMed Health⌕ Search

Biomedical subjects

K J Tuman

Publications and source records attributed to K J Tuman.

At least 19 recordsLinked to original sources
PubMed1998

An in vivo evaluation of four spinal needles used for the combined spinal-epidural technique.

UNLABELLED: The purpose of this study was to evaluate four pencil-point spinal needles commonly used for combined spinal-epidural (CSE) anesthesia. Four hundred-seven consecutive parturients undergoing cesarean delivery or labor analgesia received a CSE block with a randomly selected pencil-point spinal needle (Becton-Dickinson [B-D] 27-gauge, 119-mm Whitacre; B-D 27-gauge, 120-mm Durasafe; B-D 25-gauge, 120-mm Durasafe; or International Medical Devices' 26-gauge, 124-mm Gertie Marx). Success in obtaining cerebrospinal fluid (CSF) and the incidence of transient paresthesias and postdural puncture headache (PDPH) were compared by using chi2 testing; P < 0.05 was considered significant. Failure to obtain CSF (3%-5%) was not significantly different among spinal needles. The Gertie Marx 26-gauge needle was associated with significantly more paresthesias (29%) than the Whitacre 27-gauge needle (17%). The combined incidence of paresthesias with the Durasafe 25-gauge and Gertie Marx 26-gauge spinal needles (28%) was greater than the combined incidence of paresthesias with the Durasafe 27-gauge and Whitacre 27-gauge needles (18%). The incidence of PDPH did not differ among the four pencil-point spinal needles. We conclude that longer spinal needles are associated with a significantly more frequent incidence of transient paresthesias without residual effects. IMPLICATIONS: The use of four pencil-point spinal needles in the combined spinal-epidural technique is associated with an inconsequential incidence of spinal headache, a low incidence of paresthesias that are transient with no long-term effects, and a high degree of success independent of spinal needle length.

Anesthesia, Epidural↗
PubMed1998

Antinociceptive potentiation and attenuation of tolerance by intrathecal co-infusion of magnesium sulfate and morphine in rats.

UNLABELLED: N-methyl-D-aspartate (NMDA) antagonists, such as MK801, delay the development of morphine tolerance. Magnesium, a noncompetitive NMDA antagonist, reduces postoperative morphine requirements. The present study was designed to evaluate the effects of intrathecal co-administration of magnesium sulfate with morphine on antinociceptive potentiation, tolerance, and naloxone-induced withdrawal signs. Magnesium sulfate (40-60 microg/h) co-administration for 7 days, similar to MK801 (10 nmol/h), prevented the decline in antinociceptive response compared with morphine (20 nmol/h). Magnesium sulfate (60 microg/h) produced no antinociception, but co-infused with morphine (1 nmol/h), it resulted in potentiated antinociception compared with morphine throughout the 7-day period. Probe morphine doses after 7-day infusions demonstrated a significantly greater 50% effective dose value for morphine 1 nmol/h (109.7 nmol) compared with saline (10.9 nmol), magnesium sulfate 60 microg/h (10.9 nmol), and magnesium sulfate 60 microg/h plus morphine 1 nmol/h (11.2 nmol), which indicates that magnesium had delayed morphine tolerance. Morphine withdrawal signs after naloxone administration were not altered by the co-infusion of magnesium sulfate. Cerebrospinal fluid magnesium levels after intrathecal magnesium sulfate (60 microg/h) for 2 days increased from 17.0 +/- 1.0 microg/mL to 41.4 +/- 23.6 microg/mL, although serum levels were unchanged. This study demonstrates antinociceptive potentiation and delay in the development of morphine tolerance by the intrathecal coinfusion of magnesium sulfate and morphine in the rat. IMPLICATIONS: The addition of magnesium sulfate, an N-methyl-D-aspartate antagonist, to morphine in an intrathecal infusion provided better analgesia than morphine alone in normal rats. These results suggest that intrathecal administration of magnesium sulfate may be a useful adjunct to spinal morphine analgesia.

Analgesia↗
PubMed1998

Intrathecal bupivacaine reduces pruritus and prolongs duration of fentanyl analgesia during labor: a prospective, randomized controlled trial.

UNLABELLED: Pruritus is a frequent complication (40%-100%) of intrathecal (IT) fentanyl 25 microg (F) for labor analgesia. The addition of IT bupivacaine 2.5 mg (B) to F has been reported in a nonrandomized series to have a 17.3% incidence of pruritus. This study prospectively evaluated the incidence and distribution of pruritus in laboring parturients receiving IT F + B. Sixty-five laboring parturients were randomly assigned to receive IT F, B, or F + B as part of a combined spinal-epidural technique. Visual analog scores, sensory level, motor strength, and pruritus were recorded before injection and at intervals thereafter. When present, the distribution of pruritus was evaluated. The duration of analgesia was determined as the time from IT drug administration until the patient requested supplemental analgesia. The median duration of analgesia in the F, B, and F + B groups was 62.5, 55.0, and 94.5 min, respectively. Compared with F alone, the combination of F + B led to a decreased frequency of pruritus (36.4% vs 95%). The incidence of facial pruritus (25%) was same in the F + B and F groups; however, the occurrence of pruritus distributed over the rest of the body was significantly more frequent in the F compared with the F + B group. The combination of F + B prolongs the duration of labor analgesia compared with IT F or B alone. F + B also leads to a decreased incidence of pruritus, except in the facial region. IMPLICATIONS: When administered intrathecally with fentanyl 25 microg in laboring parturients, bupivacaine 2.5 mg attenuates the frequency of pruritus on all parts of the body except the face. This combination also results in a rapid onset and prolonged duration of labor analgesia compared with either drug alone.

Adult↗
PubMed1996

The effect of esmolol pretreatment on the incidence of regional wall motion abnormalities during electroconvulsive therapy.

Electroconvulsive therapy (ECT) is associated with dramatic increases in arterial blood pressure and heart rate (HR) that may precipitate new left ventricular regional wall motion abnormalities (RWMAs) suggestive of myocardial ischemia. The purpose of this study was to investigate the effect of pretreatment with esmolol on the incidence of RWMAs after ECT. Thirteen patients served as their own controls and, in a random fashion, received a standard succinylcholine/methohexital anesthetic for one of two ECT sessions, and an identical anesthetic with esmolol 1 mg/kg for their other ECT session. Systolic (SBP), diastolic (DBP), mean arterial pressures (MAP) and HR were recorded after drug administration and before ECT and at 1-, 2-, 4-, 5-, 10-, and 15-min intervals after ECT. Echocardiograms were obtained at baseline, after drug administration, 1 min after ECT, and at recovery 15 min later. All patients had significant increases in SBP, DBP, and MAP at 1, 2 and 4 min after ECT versus baseline, whereas HR was significantly faster at all times in the control sessions. HR was significantly slower after anesthetic induction until 2 min after ECT in the esmolol versus the control group (P < 0.05). New RWMAs were seen in only 1 of 26 (4%) ECT sessions, despite the presence of baseline RWMAs in 31% of the patients. We conclude that contrary to previously reported data, new RWMAs after ECT are uncommon. Consequently, this study was unable to demonstrate any beneficial effect of pretreatment with esmolol on the incidence of ECT-induced RWMAs.

Adrenergic beta-Antagonists↗
PubMed1996

Preoperative airway assessment: predictive value of a multivariate risk index.

Using readily available and objective airway risk criteria, a multivariate model for stratifying risk of difficult endotracheal intubation was developed and its accuracy compared to currently applied clinical methods. We studied 10,507 consecutive patients who were prospectively assessed prior to general anesthesia with respect to mouth opening, thyromental distance, oropharyngeal (Mallampati) classification, neck movement, ability to prognath, body weight, and history of difficult tracheal intubation. After induction of anesthesia, the laryngeal view during rigid laryngoscopy was graded and the ability of experienced anesthesia personnel to ventilate via a mask was determined. Poor intubating conditions (laryngoscopy Grade IV) and inability to achieve adequate mask ventilation were identified in 107 (1%) and 8 (0.07%) cases, respectively. Logistic regression identified all seven criteria as independent predictors of difficulty with laryngoscopic visualization. A composite airway risk index (derived from nominalized odds ratios calculated from the multivariate model) as well a simplified (0 = low, 1 = medium, 2 = high) risk weighting exhibited higher positive predictive value for laryngoscopy Grade IV at scores with similar sensitivity to Mallampati class III, as well as higher sensitivity at scores with similar positive predictive value. Compared to Mallampati class I fewer false-negative predictions were observed at a risk index value of 0. We conclude that improved risk stratification for difficulty with visualization during rigid laryngoscopy (Grade IV) can be obtained by use of a simplified preoperative multivariate airway risk index, with better accuracy compared to oropharyngeal (Mallampati) classification at both low- and high-risk levels.

Adult↗
PubMed1996

Aspirin does not increase allogeneic blood transfusion in reoperative coronary artery surgery.

While preoperative aspirin (ASA) therapy does not increase allogeneic transfusion in elective primary coronary artery bypass grafting (CABG) operations, the impact of ASA consumption on transfusion in cardiac operations with greater risk of bleeding has not been investigated. We examined the influence of ASA consumption on mediastinal drainage and allogenic transfusion in 317 patients undergoing reoperative CABG surgery. Patients receiving ASA or ASA containing medications within 7 days preoperatively (n = 215) had similar perioperative characteristics but were older and had smaller red cell volumes than control patients not receiving ASA (n = 102). All patients received aminocaproic acid, but autotransfusion of mediastinal blood or platelet rich plasma, aprotinin, or desmopressin were not used. No significant differences were observed between ASA and control groups with respect to postoperative hematocrit, mediastinal drainage, frequency of reexploration for excessive bleeding, amount of allogeneic packed red blood cell, fresh frozen plasma, platelet concentrate or cryoprecipitate transfusion, or the fraction of patients receiving any allogeneic blood product. There was no difference in mediastinal drainage when stratified by timing of most recent ASA ingestion. Multiple linear regression identified duration of cardiopulmonary bypass (CPB), internal mammary artery harvesting, chronic preoperative steroid therapy and use of an intraaortic balloon pump (IABP) as significant predictors of mediastinal drainage. Logistic regression demonstrated that female gender, prolonged duration of CPB, advanced age, use of IABP, and a negative history of smoking were significant independent predictors of blood product transfusion. There was no significant interaction of preoperative heparin therapy with ASA on transfusion demonstrated by univariate or multivariate analyses. These results indicate that preoperative ASA ingestion is not an important determinant of mediastinal drainage or allogeneic transfusion, even after repeat CABG operations, and that surgical and patient characteristics are more important predictors of these outcomes.

Age Factors↗
PubMed1996

Monitoring hemostasis.

As our understanding of the normal mechanisms of coagulation grows, so does our ability to monitor hemostasis. Evaluation of hemostasis will become more specific and accurate and instrumentation techniques will become simpler and more efficient as technology progress, facilitating the monitoring of hemostasis in the perioperative setting.

Blood Coagulation↗
PubMed1995

Effects of phenylephrine or volume loading on right ventricular function in patients undergoing myocardial revascularization.

The acute effects of phenylephrine (PHE) administration or intravascular volume loading on right ventricular (RV) function were examined in 34 patients undergoing elective coronary artery surgery. After anesthetic induction with sufentanil and midazolam, 20 patients received PHE to treat hypotension and increase systemic arterial pressure 20% above baseline values. PHE effectively restored arterial pressure without changing stroke index (SI), although RV ejection fraction (RVEF) declined (41.3% to 37.6%) with concomitant increases in RV end-diastolic volume index (RVEDVI) (86.3 to 97.5 mL/m2) and RV end-systolic volume index (51.8 to 63.4 mL/m2). In the first 6 to 8 hours after surgery, 18 patients received intravascular volume expansion with 5% albumin when the clinical perfusion state was inadequate and accompanied by pulmonary artery occlusion pressure (PAOP) less than 15 mmHg and a hemoglobin level greater than 8 g/dL. Volume loading with 500 mL of albumin increased SI(27.0 to 31.8mL/m2), PAOP (12.2 to 15.4 mmHg) and RVEDVI (69.0 to 86.5 mL/m2), although RVEF declined (39.3% to 37.6%). Baseline values of RVEF and SI (but not PAOP or right atrial pressure [RAP]) were lower in 9 of 18 patients who exhibited declines in RVEF after volume loading, and RAP was a poor indicator of RVEDVI (r = 0.17). RVEDVI (but not RAP or PAOP) had significant correlation with SI during volume loading. There was no relationship between the presence of hemodynamically significant right coronary artery stenoses requiring revascularization or other perioperative factors with the response to PHE before revascularization or to volume loading after revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Angiotensin-converting enzyme inhibitors increase vasoconstrictor requirements after cardiopulmonary bypass.

Preoperative use of angiotensin-converting enzyme (ACE) inhibitors is common and has been associated with hypotension at separation from cardiopulmonary bypass (CPB). This study prospectively examined the influence of chronic preoperative ACE inhibitor use and other perioperative factors on the incidence of vasoconstrictor therapy required to maintain systolic blood pressure at more than 85 mm Hg despite a normal cardiac output after CPB in 4301 adults undergoing elective coronary artery and/or valve surgery. Hypothermic, nonpulsatile CPB and either opioid or ketamine-benzodiazepine anesthesia were common features of the operations. At least two vasoconstrictor infusions (phenylephrine, norepinephrine, or dopamine) were required for low perfusion pressure despite adequate cardiac output after CPB in 7.7% of 519 ACE-inhibited patients and 4.0% of 3782 patients not receiving ACE inhibitors (P = 0.0001). In the first 4 h after arrival in the intensive care unit, the need for vasoconstrictor infusions to treat hypotension with adequate cardiac output did not differ, although more ACE-inhibited patients (6.4%) exhibited low values of systemic vascular resistance (< 600 dyne.s.cm-5) than patients not receiving ACE inhibitors (2.8%; P = 0.0002). Logistic regression analysis identified preoperative ACE inhibitor use, congestive heart failure, poor left ventricular function, duration of CPB, reoperative surgery, age, and opioid anesthesia as independent risk factors for requiring > or = 2 vasoconstrictor infusions after CPB. No other preoperative drug therapy significantly altered this outcome.

Aged↗
PubMed1994

Evaluation of coagulation during cardiopulmonary bypass with a heparinase-modified thromboelastographic assay.

Thromboelastography (TEG) is a useful method of assessing perioperative coagulation function in patients undergoing cardiac surgery. The presence of significant amounts of heparin in blood samples, however, prevents determination of changes in coagulation function by TEG or introduces artifactual error if samples contain heparin that is not present in vivo. For these reasons, whole blood coagulation function monitoring with TEG has not been feasible during cardiopulmonary bypass (CPB) with heparin anticoagulation. In this study, data obtained from 42 volunteers are presented to describe the effects of heparinase on TEG variables in the presence and absence of heparin. These data indicate that heparinase does not affect TEG parameters of whole blood not containing heparin and reverses the TEG effects of low levels of heparin contamination. Subsequently, 51 patients undergoing coronary artery surgery were studied using a modified TEG assay that incorporates in vitro application of heparinase to allow measurement of TEG parameters before, during, and after CPB. Heparinase-modified TEG assays facilitated diagnosis of heparin contamination in preoperative blood samples and permitted baseline TEG evaluation in patients receiving preoperative heparin infusions. Heparinase-modified TEG assays revealed declines in alpha and MA values during CPB, which persisted and significantly correlated with values after protamine infusion (alpha: r = 0.77, P = 0.001; MA: r = 0.78, P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bioimpedance hemodynamics compared to pulmonary artery catheter monitoring during orthotopic liver transplantation.

Simultaneous cardiac output measurements were obtained using bioimpedance (BI) and thermodilution (TD) methods in 10 patients undergoing orthotopic liver transplantation (OLT). BI and TD data were collected during five intraoperative phases of OLT. Linear regression revealed significant correlation between BI and TD (r = 0.8, P = 0.001) with a slope of regression of 0.64. Bias analysis demonstrated a negative of BI (-0.26) when compared with TD.Sv-O2 correlated poorly with cardiac index determined by TD (r = 0.41) or BI (r = .47). BI is an accurate reproducible method for measuring cardiac output and may be a useful adjunct to the pulmonary artery catheter for hemodynamic monitoring during OLT.

Adult↗