Evaluation of a new design pulmonary artery catheter for intraoperative ventricular pacing

A new design pulmonary artery catheter and pacing probe were evaluated in 30 patients undergoing cardiac surgery. Ventricular pacing was attempted before, during, and after cardiopulmonary bypass. Ventricular current threshold, output, resistance, and R wave sensitivity were measured during all three periods. Successful pacing was achieved in 69 of 72 attempts, the vast majority completed in less than four minutes. Pacing thresholds and R wave sensitivities were within acceptable ranges and compatible with commercial pulse generators. Ventricular pacing can be quickly and reliably established with this type of pacing pulmonary artery catheter. The results suggest this system can be used to effect cardiac pacing in the patient requiring emergency extrinsic pacemaker support.

Multicenter study of contaminated percutaneous injuries in anesthesia personnel

BACKGROUND

Anesthesia personnel are at risk for occupational infection with bloodborne pathogens from contaminated percutaneous injuries (CPIs). Additional information is needed to formulate methods to reduce risk.

METHODS

The authors analyzed CPIs collected during a 2-yr period at 11 hospitals, assessed CPI underreporting, and estimated risks of infection with human immunodeficiency virus and hepatitis C virus.

RESULTS

Data regarding 138 CPIs were collected: 74% were associated with blood-contaminated hollow-bore needles, 74% were potentially preventable, 30% were considered high-risk injuries from devices used for intravascular catheter insertion or obtaining blood, and 45% were reported to hospital health services. Corrected for injury underreporting, the CPI rate was 0.27 CPIs per yr per person; per full-time equivalent worker, there were 0.42 CPIs/yr. The estimated average 30-yr risks of human immunodeficiency virus or hepatitis C virus infection per full-time equivalent are 0.049% and 0.45%, respectively. Projecting these findings to all anesthesia personnel in the United States, the authors estimate that there will be 17 human immunodeficiency virus infections and 155 hepatitis C virus infections in 30 yr.

CONCLUSIONS

Performance of anesthesia tasks is associated with CPIs from blood-contaminated hollow-bore needles. Thirty percent of all CPIs would have been high-risk for bloodborne pathogen transmission if the source patients were infected. Most CPIs were potentially preventable, and fewer than half were reported to hospital health services. The results identify devices and mechanisms responsible for CPIs, provide estimates of risk levels, and permit formulation of strategies to reduce risks.

Protein tyrosine phosphorylation in signalling pathways leading to the activation of gelatinase A: activation of gelatinase A by treatment with the protein tyrosine phosphatase inhibitor sodium orthovanadate

Fibroblasts in monolayer culture secrete gelatinase A (MMP2; 72 kDa type IV collagenase) only in its proenzyme form. Unlike other secreted matrix metalloproteinases, progelatinase A is refractory to activation by serine proteinases. Disparate agents, including monensin, cytochalasin D, and concanavalin A, have been found to mediate the activation of gelatinase A zymogen secreted by fibroblast monolayers. Our finding that monensin-mediated activation can be reversed by the protein tyrosine kinase inhibitor genistein (Li et al., Experimental Cell Research 232 (1997) 332) prompted us to investigate the effect of the specific inhibitor of protein tyrosine phosphatases, sodium orthovanadate, on progelatinase A activation. Treatment of fibroblast monolayers with orthovanadate also results in the secretion of activated gelatinase A. This activation is dose- and time-dependent, requires protein synthesis, and is associated with cell membranes. Vanadate-mediated activation does not occur in the presence of herbimycin A, a protein tyrosine kinase inhibitor. As with progelatinase activation mediated by monensin, concanavalin A, and cytochalasin D, orthovanadate treatment results in increased synthesis of the membrane proteinase MT1-MMP, that can catalyze the activation of progelatinase A. Protein tyrosine kinase inhibitors are able to prevent the increase of MT1-MMP mRNA, as shown by Northern blot and RT-PCR. In addition, orthovanadate potentiates the effects of monensin and concanavalin A. While treatment with monensin or concanavalin A result only in an increase of the putative activator MT1-MMP, orthovanadate also reduces the production of the specific inhibitor TIMP-2. These experiments implicate protein tyrosine phosphorylation in the signal transduction pathways which lead to the activation of progelatinase A.

Activation of gelatinase A (72-kDa type IV collagenase) induced by monensin in normal human fibroblasts

In monolayer culture, fibroblasts secrete all matrix metalloproteinases, including gelatinase A (72-kDa type IV collagenase), as inactive zymogens. Whereas limited proteolysis by plasmin or other matrix metalloproteinases (MMPs) can accomplish the extracellular activation of other proenzymes in this family, gelatinase A proenzyme is uniquely refractory to cleavage by such proteinases. Previously it has been shown that fibroblasts cultured in the presumably more physiologic culture milieu of a type I collagen lattice can be induced to secrete active gelatinase A. In monolayer culture, however, the plant lectin concanavalin A will induce gelatinase A activation. Here we show that in monolayer culture activation of gelatinase A by normal fibroblasts is also induced by the sodium ionophore monensin. The monensin response is dose-dependent, time-dependent, requires protein synthesis, and is specific to gelatinase A among the secreted matrix metalloproteinases. The activator appears to be associated with cell membranes and may be membrane-type matrix metalloproteinase 1(MT-MMP1). Both mRNA and immunodetectable protein of MT-MMP1 are increased with monensin treatment while message for the protein inhibitor of gelatinase A, TIMP-2, is unchanged. The monensin-induced signal transduction pathway leading to gelatinase activation in monolayer culture appears to be different from the integrin-mediated pathway operative in the collagen lattice system. The tyrosine kinase inhibitor genistein blocks monensin activation of gelatinase A in monolayer culture. In contrast, genistein has no effect on proenzyme activation in the collagen lattice. Likewise, the cyclooxygenase inhibitor indomethacin abrogates the monensin effect in monolayer culture and can be reversed by addition of exogenous prostaglandin E2 (PGE2). Neither indomethacin nor PGE2 affects activation of gelatinase A in the collagen lattice.

Intracellular activation of gelatinase A (72-kDa type IV collagenase) by normal fibroblasts

Normal fibroblasts cultured as monolayers secrete matrix metalloproteinases (MMP), including gelatinase A (72-kDa type IV collagenase) as inactive zymogens. Previously we found that normal fibroblasts cultured in a type I collagen lattice (dermal equivalent) secrete active gelatinase A. Here we show that the activation of progelatinase A occurs within the cell and that the activator copurifies with Golgi membranes. Cell extracts of fibroblasts cultured in collagen lattices contain active 62-kDa gelatinase A at least 4-6 h before active enzyme is detected in the culture medium. Pulse-chase experiments confirm these results. The activator is membrane-bound and localizes to the Golgi-enriched fraction. Highly purified plasma membranes from lattice cultures are unable to convert gelatinase A from the zymogen to its active form. The activator may be a metalloproteinase because EDTA prevents activation of exogenous proenzyme by membrane fractions. Membrane-type MMP1, the enzyme thought to be responsible for activation of gelatinase A on the plasma membrane of tumor cells, shows no significant change in either mRNA or protein levels during lattice culture. Intracellular levels of gelatinase A mRNA and protein increase during the culture period, and tissue inhibitor of metalloproteinases concentration does not change. Because of the greater availability of tissue inhibitor of metalloproteinases-free proenzyme as a substrate for the activator, it is possible that membrane-type MMP1 is the activating enzyme. In that case, malignant transformation may involve a change in the localization of the activator to the plasma membrane.

Medical waste in the environment: do anesthesia personnel have a role to play?

STUDY OBJECTIVE

To conduct a feasibility study of the mechanics of recycling single-use anesthesia breathing systems and practices of anesthesiologists and nurse-anesthetists in a tri-state region.

STUDY DESIGN

Two-part, open, prospective analysis using pre-printed questionnaire and cost/time analysis of labor and materials.

SETTING

Questionnaire sent to 413 anesthesiology departments in Pennsylvania, New Jersey, and Delaware, and hospital/recycling facility for evaluation of time and cost.

MEASUREMENTS AND MAIN RESULTS

Time to disassemble and sort the breathing circuits, analysis of costs and obtainable income from byproducts of recycling, and standard survey questionnaire concerning demographic characteristics of respondents and individual department/hospital practitioners. Data analysis included analysis of variance and Kruskal-Wallis tests. Pilot analysis: Sorting of circuits to economic component required ten minutes at an average cost of $1.60 Value of scraps obtainable was $3.44, leaving a gross margin of $1.84 for a box of 18 circuits. Benefit analysis: Extended reduction in the regulated medical waste in our operating room of 16,875 lb, saving $4,387.50 per year. With generation of revenue from scrap, the net gain is $5,994.64 per yr. Questionnaire: Majority (83%) of departments polled would participate in recycling implemented by suppliers. Most respondents would not consider (58%) recycling unless mandated by law.

CONCLUSION

The program described is cost-effective and environmentally beneficial.

Comparison of cleavage site specificity of gelatinases A and B using collagenous peptides

The gelatinases (type IV collagenases) are members of the matrix metalloproteinase family that not only have a high degree of structural homology but are known to be nearly identical in their digestion profile against macromolecular substrates. We have shown previously that the preferred cleavage sites in the hydrolysis of type I gelatin, catalyzed by gelatinase A (72 kDa type IV collagenase), are bracketed by hydroxyproline in the P5 and P5' positions. In this report, a kinetic investigation using a series of collagenous dodecylpeptides in which the P5 and P5' hydroxyprolines were systematically varied and used as substrates for recombinant human gelatinase A, we show that replacement with either proline or alanine always resulted in increased Km. In contrast, substitution of the hydroxylated amino acids tyrosine and serine at P5 and P5' reduced the Km significantly, indicating that the hydroxyl moiety of the hydroxyproline is the functional group responsible for favorable enzyme-substrate affinity. This was shown by the kcat/Km ratio, which was doubled by the substitution of serine in that site. Cleavage of the same series of dodecylpeptides by recombinant human gelatinase B (92 kDa type IV collagenase) showed a very different kinetic profile for which no patterns were discernible. In subsequent comparisons of the two enzymes, it was found that gelatinase B cleaved the thiopeptolide substrate AcProLeuGly-S-LeuGly-OC2H5 at double the velocity of gelatinase A. In contrast, gelatinase A digested type I gelatin about 2.5-times faster than gelatinase B. SDS-PAGE analysis of gelatin cleavage products showed different patterns of product peptides for each enzyme. Further comparisons of the proteinases using synthetic peptide substrates with variations in size and in substituents at the P2' site again showed marked kinetic differences. Although these two matrix metalloproteinases seem similar in that they are both gelatinolytic and can degrade a nearly identical battery of macromolecular matrix components including type IV collagen, it is clear from these results that they are very different enzymatically. Since the regulatory portions of gelatinases A and B differ markedly, it has been assumed that the enzymes serve the same function, but respond to different stimuli. The differences in substrate specificity described herein suggest that their proposed physiological roles may require reevaluation.

Intraoperative hemodynamic, renin, and catecholamine responses after prophylactic and intraoperative administration of intravenous enalaprilat

This study was designed to evaluate effects of enalaprilat, an angiotensin-converting enzyme inhibitor, on hemodynamic and hormonal responses during surgery at endotracheal intubation, incision, and limb-tourniquet inflation. Thirty patients undergoing limb procedures with general anesthesia (N2O/narcotic technique) and a pneumatic tourniquet were randomized to receive either preoperative enalaprilat (1.25 mg intravenously [i.v.] 20 min prior to induction) or intraoperative enalaprilat (0.625 mg i.v. at the onset of tourniquet-associated hypertension), with appropriate placebo controls. Arterial blood pressure and heart rate increased significantly in response to intubation in the placebo group. Although there were no significant differences in catecholamine levels, plasma renin activity was significantly increased at postincision in the preoperative-enalaprilat group versus the placebo group. This suggests that activation of the renin-angiotensin system may play a key role in mediation of intraoperative hemodynamic responses to endotracheal intubation. With respect to tourniquet hypertension, preoperative or intraoperative treatment with enalaprilat reduced neither the pressor response to tourniquet inflation nor the amount of enflurane subsequently required to control arterial blood pressure. These findings suggest that this response is mediated by pain pathways, and may be treated more effectively with anesthesia/analgesia.

Activation of 72-kDa type IV collagenase/gelatinase by normal fibroblasts in collagen lattices is mediated by integrin receptors but is not related to lattice contraction

The matrix metalloproteinase 72-kDa type IV collagenase (also known as gelatinase A) is thought to be involved in both normal connective tissue remodeling and invasive pathological processes. Like other matrix metalloproteinases, 72-kDa type IV collagenase is secreted by fibroblast monolayers as an inactive proenzyme, but is unique among this enzyme family in that it is not activated by serine proteinases such as plasmin. However, when fibroblasts are cultured in a collagen lattice, a situation thought to better approximate in vivo conditions, we have invariably found much of the secreted 72-kDa type IV collagenase in its enzymatically active 62-kDa form. Although collagen lattice contraction appeared to be required for the activation of 72-kDa type IV collagenase, we have found that the process of contraction can be dissociated from proenzyme activation. Both cytochalasin D and alpha-methylmannoside completely blocked lattice contraction, but not proenzyme activation. Furthermore, the monoclonal antibody M-13, which is directed against the beta 1 integrin chain, blocked collagen lattice contraction but not 72-kDa type IV procollagenase activation. At concentrations significantly higher than required to block lattice contraction or cell adhesion to collagen, M-13 was able to inhibit proenzyme activation. A second monoclonal antibody to the beta 1 integrin, P5D2, had little effect on collagen lattice contraction at low concentrations, but could significantly inhibit the activation of 72-kDa type IV procollagenase. Antibodies to the integrin alpha 2 chain also inhibited proenzyme activation. These data show that the activation of 72-kDa type IV collagenase proenzyme, like collagen lattice contraction, is mediated by beta 1 integrin receptors, possibly alpha 2 beta 1. Although both anti-beta 1 antibodies used are directed to the same site on the integrin chain, the fact that each antibody preferentially blocks a different event, either lattice contraction or activation of 72-kDa type IV collagenase, suggests the existence of branch points in the receptor-mediated signal transduction pathway.

Does the use of methylmethacrylate cement in total shoulder replacement induce hemodynamic or pulmonary instability?

STUDY OBJECTIVE

To investigate whether the use of methylmethacrylate cement causes hemodynamic or pulmonary instability during total shoulder replacement surgery.

DESIGN

Prospective, nonrandomized study.

SETTING

Operating room.

PATIENTS

9 ASA physical status I and II patients.

INTERVENTIONS

A 20-gauge radial artery catheter was placed in the wrist opposite the surgical site. Sedation with midazolam was provided, and a pulmonary artery catheter was placed through an 8.5-Fr introducer into the patient's right internal jugular vein.

MEASUREMENTS AND MAIN RESULTS

Before induction of anesthesia, systolic, diastolic, and mean arterial blood pressures; heart rate; central venous pressure; systolic, diastolic, and mean pulmonary artery pressures; pulmonary capillary wedge pressure; and thermodilution cardiac output measurements were obtained. Arterial and mixed venous blood gas samples also were collected and analyzed for calculation of Qs/Qt. These hemodynamic and pulmonary parameters were measured again just before cementing of each prosthesis with methylmethacrylate cement and at 1, 5, 10, and 20 minutes after cementing. There were no statistically significant changes in any of the measured hemodynamic parameters at any time. There was no statistically significant difference in the calculated intrapulmonary shunt fraction.

CONCLUSION

In this study population, the use of methylmethacrylate for total shoulder replacement was not associated with adverse hemodynamic events or increased intrapulmonary shunting.

A comparison of desflurane and isoflurane in prolonged surgery

STUDY OBJECTIVE

To compare desflurane with isoflurane in several anesthetic situations.

DESIGN

Intubating conditions, hemodynamic response to intubation, maintenance hemodynamics, and speed of recovery from desflurane and isoflurane anesthesia were evaluated. In addition, interaction with a muscle relaxant at low and high concentrations of the anesthetics were compared.

SETTING

Thomas Jefferson University Hospital.

PATIENTS

Thirty-two patients who received general anesthesia for lengthy, mostly orthopedic procedures.

INTERVENTIONS

Immediately after induction with thiopental sodium, desflurane or isoflurane in nitrous oxide-oxygen was administered via face mask. Anesthesia was deepened until end-tidal concentration reached 1.7 minimum alveolar concentration (MAC). The trachea was intubated without the aid of a muscle relaxant. Heart rate (HR) and blood pressure (BP) were recorded before and at 1, 2, 4, 5, and 10 minutes after intubation. Noninvasive cardiac output (CO) and systemic vascular resistance (SVR) were determined while the patient was awake, immediately before intubation, and at 5 and 10 minutes after intubation. Following intubation, the concentration of desflurane or isoflurane was lowered until the end-tidal concentration reached 0.65 MAC (low-MAC group), 1.25 MAC (high-MAC group), or 0 MAC (control group). Pancuronium bromide in 0.005 mg/kg doses was administered incrementally until T1 (first twitch of train-of-four) was depressed more than 90%. ED50 and ED95 for pancuronium with balanced anesthesia and for desflurane or isoflurane in low and high MACs, as well as speed of recovery, were determined. The time to responsiveness and awakening also was determined.

MEASUREMENTS AND MAIN RESULTS

There was no significant difference between desflurane and isoflurane in intubating conditions or in BP or HR response to tracheal intubation. Both anesthetics increased HR significantly during induction. BP rose with desflurane at the preintubation point; other points showed no difference. A hyperdynamic response of increased HR and BP above 20% of baseline values was seen more frequently with desflurane (n = 7) than with isoflurane (n = 1). CO was elevated at all times after induction for low and high concentrations of both drugs, while SVR decreased over the same time with no significant difference between drugs. ED50 and ED95 for pancuronium were similar under desflurane and isoflurane at both low and high MAC, but they were significantly lower than under balanced anesthesia. Awakening times were similar for desflurane and isoflurane.

CONCLUSIONS

Desflurane is similar to isoflurane in providing anesthesia for intubation and maintenance. Desflurane tends to increase HR and occasionally causes a hyperdynamic response during rapid deepening of anesthesia. It is very similar to isoflurane in its interaction with pancuronium.

Time-course of respiratory depression after an alfentanil infusion-based anesthetic

Postoperative respiratory depression after alfentanil administration has been described in several case reports. The effects of a prolonged alfentanil infusion on the CO2 response curve or cognitive function have not been studied. Twenty-one ASA physical status I or II patients were studied after a prolonged alfentanil infusion (> 90 min) to determine the incidence of postoperative respiratory depression, arterial O2 desaturation, and impairment of cognitive function. Each patient's recovery was observed at 30-min intervals for evidence of respiratory depression (utilizing the Read CO2 rebreathing method), desaturation by pulse oximetry (severe desaturation defined as arterial O2 saturation < 90%), and cognitive function (utilizing Trieger dot and digit substitution tests). Plasma samples were also examined for secondary elevations in alfentanil plasma concentrations. Significant depression of the CO2 response curve and cognitive function was found up to 1 h postoperatively. Arterial O2 desaturation was seen in 11 of 21 patients (52%). No correlation was found between arterial O2 desaturation and cognitive function scores or CO2 rebreathing results. Increased depression of the CO2 response curve was not necessarily associated with severe desaturation episodes. A secondary increase in plasma alfentanil concentration was detected in 5 of the 21 patients (24%), but these patients did not experience further depression of the CO2 response curve. We conclude that prolonged alfentanil administration may result in severe arterial O2 desaturation with significant depression of the hypercapnic respiratory drive during the first hour in the postanesthesia care unit, even though the majority of our patients were easily aroused in response to verbal stimuli.

Laterality and modality-specific effects of chronic pain

Previous investigations indicated that thresholds to nonpainful tactile stimuli were elevated in chronic-pain patients when compared with pain-free individuals (Seltzer & Seltzer, 1986; Seltzer et al., 1988). The present study attempted to determine whether thresholds to tactual and visual stimuli also were elevated by chronic pain. Furthermore, lateralization of the pain effect on tactile thresholds was assessed by obtaining thresholds from both left and right arms. A decrease in tactile sensitivity to nonpainful stimuli in chronic-pain patients was confirmed, but laterality of the effect was not demonstrated. Visual thresholds were not significantly affected by chronic pain. The data in the present study, taken together with other data, support the proposition that pain does not affect right hemispheric processes more than left hemispheric processes.

The effect of the prone position on venous pressure and blood loss during lumbar laminectomy

STUDY OBJECTIVE

To determine the effects of three different prone support systems (Andrews spinal surgery frame, Cloward surgical saddle, and longitudinal bolsters) on inferior vena cava (IVC) and superior vena cava (SVC) pressures; the validity of measuring central venous pressure (CVP) for the determination of ideal positioning of the patient; and the relationship among frame type, blood loss, and hemodynamic measurements.

DESIGN

Prospective, randomized study of the hemodynamic effects of the prone position.

SETTING

Inpatient surgery at a university hospital (regional spinal cord injury treatment center).

PATIENTS

Eighteen patients free of significant coexisting disease (ASA physical status I and II) undergoing elective lumbar laminectomy.

INTERVENTIONS

Patients were assigned to one of three support frames and measurement of SVC pressure, IVC pressure, and mean arterial pressures (MAP) were obtained supine, prone, and after repositioning. These pressures and measured blood loss were obtained every 15 minutes during the surgical laminectomy portion of the procedure.

MEASUREMENTS AND MAIN RESULTS

Patients positioned on the Andrews frame had decreased mean SVC and IVC pressures from 8.7 mmHg and 8.4 mmHg in the supine position to 3.3 mmHg and 1.8 mmHg in the prone position, respectively (p less than 0.001). Prone position CVP also was significantly lower in the Andrews group compared with that in the other two groups (p less than 0.001). Repositioning efforts did not significantly decrease CVP. Blood loss was higher in the Cloward group (1,150 +/- 989 ml) than in the Andrews (245 +/- 283 ml) and bolsters (262 +/- 188 ml) groups (p less than 0.02).

CONCLUSIONS

Increased blood loss was not associated with increased SVC or IVC pressure, nor was there any significant correlation between any demographic or hemodynamic variable and blood loss. There was no evidence that CVP is useful in determining the ideal prone position in patients undergoing lumbar laminectomy.

P & T Committee response to evolving technologies: preparing for the launch of high-tech, high-cost products. Roundtable discussion

P & T Committees are entering an exciting era in which the introduction of biotechnology-derived pharmaceuticals is providing life-saving opportunities for conditions for which there was little or no hope for a cure. The P & T Committee at Thomas Jefferson University Hospital has anticipated the challenge that these novel therapeutics present, and has already positioned itself for the pending approval of the first therapeutic human monoclonal antibody. Nebacumab (HA-1A, formerly known as Centoxin; by Centocor) will be used for the treatment of gram-negative sepsis. Although this antiendotoxin has a good side effect profile, its use also carries a high price tag. This will raise several difficult ethical issues once the product is introduced. In this exclusive Hospital Formulary roundtable, members of Thomas Jefferson's P & T Committee and Technology Assessment Subcommittee provide their insights for responsibly managing a high-tech, high-cost product such as nebacumab.

Intubating conditions after pipecuronium bromide: the influence of dose and time

STUDY OBJECTIVE

To determine the intubating conditions following the administration of pipecuronium bromide in doses of two (0.07 mg/kg) or three (0.1 mg/kg) times ED95 (average dose that gives 95% block of the first twitch).

DESIGN

To compare intubating conditions at 11/2 and 21/2 minutes in 41 patients receiving balanced anesthesia.

SETTING

Surgical patients at Thomas Jefferson University Hospital.

PATIENTS

Forty-one patients undergoing surgical procedure who received general anesthesia.

INTERVENTIONS

After obtaining a stable baseline of train-of-four (TOF), 41 patients randomly received either 0.07 mg/kg or 0.1 mg/kg of pipecuronium as a single intravenous (IV) bolus dose, and the trachea was intubated either at 11/2 or 21/2 minutes.

MEASUREMENTS AND MAIN RESULTS

Intubating conditions at 21/2 minutes appeared significantly better than those at 11/2 minutes, regardless of the pipecuronium dose. The mean time for T1 (first twitch of TOF) to reach 50% and 90% suppression was 1.36 +/- 0.51 minutes and 2.29 +/- 0.8 minutes, respectively, for the 0.07 mg/kg dose and 1.07 +/- 0.27 minutes and 1.72 +/- 0.45 minutes, respectively, for the 0.1 mg/kg dose. This did not make a significant difference in intubating conditions at either time. The time to 25% recovery of T1 was 68.2 +/- 22 minutes for the 0.07 mg/kg dose and 121.5 +/- 49 minutes for the 0.1 mg/kg dose. In patients who had spontaneous recovery of T1 to between 10% and 25% of control, administration of neostigmine or edrophonium resulted in identical recovery in 10 minutes. However, in patients with less than 10% spontaneous recovery of T1, neostigmine appeared to be superior to edrophonium.

CONCLUSION

Pipecuronium has a relatively rapid onset. The trachea could be intubated successfully in 11/2 minutes with a dose of either 0.07 mg/kg or 0.1 mg/kg. If the clinical situation requires perfect relaxation with no movement or bucking, we recommend waiting at least 21/2 minutes.

A risk-specific anesthesia consent form may hinder the informed consent process

STUDY OBJECTIVE

To evaluate the effect of a preprinted, risk-specific consent form on the amount of anesthetic risk information patients retain from the preoperative interview.

DESIGN

Postoperative survey of consecutive inpatients to determine risk information retained before and after implementation of a preprinted anesthesia consent form, using standard preoperative risk discussions.

SETTING

Inpatient units of a university medical center.

PATIENTS

Two groups of patients, both of whom received a standard oral discussion of anesthetic risk information, were compared. Patients in the control group (125 consecutive inpatients) received this information only orally and were interviewed two weeks prior to implementation of a preprinted anesthesia consent form. Patients in the study group (92 consecutive inpatients) received this information orally and via a preprinted consent form and were interviewed between the fourth and sixth weeks after implementation of a preprinted anesthesia consent form.

INTERVENTIONS

Anesthesia residents discussed five standard anesthetic risks with elective, adult inpatients (n = 233) during a two-week period immediately before and between the fourth and sixth weeks after instituting the mandatory use of a risk-specific anesthesia consent form. These patients were interviewed postoperatively by one of the authors to determine the amount of anesthesia risk information they retained.

MEASUREMENTS AND MAIN RESULTS

Results of the postoperative survey showed that patients in the control group retained more information concerning anesthetic risks than did those in the study group (33% vs 19%, p less than 0.01).

CONCLUSIONS

To improve the informed consent process, either a better method of presenting the preprinted, risk-specific consent form or another method of simultaneously conveying and documenting risk information is needed.

Cleavage specificity of human skin type IV collagenase (gelatinase). Identification of cleavage sites in type I gelatin, with confirmation using synthetic peptides

Type IV collagenase (gelatinase) readily cleaves denatured collagen into very small peptides. Large cyanogen bromide fragments (25 kDa) of type I collagen are degraded at the same rate as the complete alpha-chain. A number of the gelatinolytic cleavage sites of alpha 1(I)CB7 and alpha 1(I)CB8, representing 50% of the collagen alpha-chain, were determined by sequence analysis of product peptides. In addition to the expected cleavage between glycine and hydrophobic residues, several other cleavage sites were identified. These sites were Gly-Glu, Gly-Asn, and Gly-Ser. Basic residues were found adjacent to the cleavage site in several cases. Hexapeptides containing these unexpected cleavage sites were synthesized, and Km and kcat values were determined. All but one of the Km values were in the submillimolar range, and turnover numbers for the peptides uncharged at the carboxyl terminus were on the order of 10,000/h. Of particular significance was the finding that hydroxyproline occurs 5 residues from the cleavage site in all carboxyl-terminal product peptides and also occurs 5 residues from the cleavage site in seven of nine amino-terminal product peptides. A requirement for hydroxyproline may be of importance in determining the specificity of this enzyme for denatured collagenous substrates.

Differential susceptibility of type X collagen to cleavage by two mammalian interstitial collagenases and 72-kDa type IV collagenase

We have studied the degradation of type X collagen by human skin fibroblast and rat uterus interstitial collagenases and human 72-kDa type IV collagenase. The interstitial collagenases attacked the native type X helix at two loci, cleaving residues Gly92-Leu93 and Gly420-Ile421, both scissions involving Gly-X bonds of Gly-X-Y-Z-A sequences. However, the human and rat interstitial enzymes displayed an opposite and substantial selectivity for each of these potential sites, with the uterine enzyme catalyzing the Gly420-Ile421 cleavage almost 20-fold faster than the Gly92-Leu93 locus. Values for enzyme-substrate affinity were approximately 1 microM indistinguishable from the corresponding Km values against type I collagen. Interestingly, in attacking type X collagen, both enzymes manifested kinetic properties intermediate between those characterizing the degradation of native and denatured collagen substrates. Thus, energy dependence of reaction velocity revealed a value of EA of 45 kcal, typical of native interstitial collagen substrates. However, the substitution of D2O for H2O in solvent buffer failed to slow type X collagenolysis significantly (kH/kD = 1.1), in contrast to the 50-70% slowing (kH/kD = 2-3) observed with native interstitial collagens. Since this lack of deuterium isotope effect is characteristic of interstitial collagenase cleavage of denatured collagens, we investigated the capacity of another metalloproteinase with substantial gelatinolytic activity, 72-kDa type IV collagenase, to degrade type X collagen. The 72-kDa type IV collagenase cleaved type X collagen at both 25 and 37 degrees C, and at loci in close proximity to those attacked by the interstitial enzymes. No further cleavages were observed at either temperature with type IV collagenase, and although values for kcat were not determined (due to associated tissue inhibitor of metalloproteinases-2), catalytic rates appeared to be substantial in comparison to the interstitial enzymes. In contrast, type X collagen was completely resistant to proteolysis by stromelysin. Type X collagen thus appears to be highly unusual in its susceptibility to degradation by both interstitial collagenase and another member of the metalloproteinase gene family.

A comparison of labetalol and nitroprusside for inducing hypotension during major surgery

The hemodynamic and intrapulmonary shunt effects of intravenous labetalol and nitroprusside were compared during induced hypotension for major spinal surgery. A randomized, double-blind protocol was used in which 20 patients, ASA physical status I or II, received either nitroprusside infusion (n = 10) or labetalol bolus injections of 10 mg every 10 min (n = 10) until mean arterial blood pressure was reduced to 55-60 mm Hg. Pulmonary artery pressures were measured and mixed venous samples obtained via a pulmonary artery catheter. Nitroprusside increased heart rate significantly more than labetalol during the period of hypotension. When compared with prehypotension baseline values, nitroprusside increased heart rate significantly with a concomitant significant decrease in systemic vascular resistance. Cardiac output increased significantly 60 min after hypotension was achieved in patients treated with nitroprusside. Systemic vascular resistance decreased significantly below baseline levels in patients treated with labetalol but without changes in cardiac output, heart rate, or mean pulmonary artery pressure. There was a 122% increase in intrapulmonary shunt with nitroprusside administration, compared with an 11% increase with labetalol. Labetalol was effective for inducing hypotension and was not associated with an increase in heart rate, intrapulmonary shunt, or cardiac output as seen with nitroprusside.

Relationship between arterial carbon dioxide and end-tidal carbon dioxide when a nasal sampling port is used

End-tidal carbon dioxide (ETCO2) values obtained from awake nonintubated patients may prove to be useful in estimating a patient's ventilatory status. This study examined the relationship between arterial carbon dioxide tension (PaCO2) and ETCO2 during the preoperative period in 20 premedicated patients undergoing various surgical procedures. ETCO2 was sampled from a 16-gauge intravenous catheter pierced through one of the two nasal oxygen prongs and measured at various oxygen flow rates (2, 4, and 6 L/min) by an on-line ETCO2 monitor with analog display. Both peak and time-averaged values for ETCO2 were recorded. The results showed that the peak ETCO2 values (mean = 38.8 mm Hg) correlated more closely with the PaCO2 values (mean = 38.8 mm Hg; correlation coefficient r = 0.76) than did the average ETCO2 values irrespective of the oxygen flow rates. The time-averaged PaCO2-ETCO2 difference was significantly greater than the PaCO2-peak ETCO2 difference (P less than 0.001). Values for subgroups within the patient population were also analyzed, and it was shown that patients with minute respiratory rates greater than 20 but less than 30 and patients age 65 years or older did not differ from the overall studied patient population with regard to PaCO2-ETCO2 difference. A small subset of patients with respiratory rates of 30/min or greater (n = 30) did show a significant increase in the PaCO2-ETCO2 difference (P less than 0.001). It was concluded that under the conditions of this study, peak ETCO2 values did correlate with PaCO2 values and were not significantly affected by oxygen flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Nicardipine versus placebo for the treatment of postoperative hypertension

Postoperative hypertension can cause serious complications, including bleeding from fresh anastomoses, cardiovascular accident, and myocardial ischemia. Therefore rapid control of blood pressure is essential to prevent poor outcome. In this study, 30 American Society of Anesthesiologists class I and II patients who did not have cardiac surgery and subsequently developed postoperative hypertension were randomly assigned to receive either nicardipine, a new dihydropyridine calcium channel blocker, or placebo. Intravenous nicardipine was given as a loading bolus of 10 mg/hr for 5 minutes and was titrated to 15 mg/hr if needed to achieve a therapeutic response. After therapeutic response, intravenous nicardipine was decreased to 3 mg/hr and subsequently titrated in increments of 1.0 to 2.5 mg/hr to maintain blood pressure control. Systolic and diastolic blood pressures during titration and maintenance did not differ significantly from preoperative levels in patients treated with nicardipine. The mean time to therapeutic response for the nicardipine-treated group was 8.67 +/- 1.46 minutes, and the median time to offset of action was 15 minutes. Eleven of the 12 patients who received placebo were crossed over to antihypertensive therapy, and of these, 10 received intravenous nicardipine. In this group all achieved therapeutic response in 7.3 +/- 1.18 minutes. The usefulness of intravenous nicardipine for postoperative hypertension was demonstrated in this study by: (1) the rapid control of blood pressure, (2) its continued efficacy during maintenance, and (3) little need to adjust dosage to control blood pressure.

Cleavage specificity of type IV collagenase (gelatinase) from human skin. Use of synthetic peptides as model substrates

Type IV collagenase (gelatinase) has a marked substrate specificity for denatured collagen (gelatin). Cleavage site specificity of type IV collagenase from human skin was determined using small collagenous peptides with varied sequences around Gly-Leu or Gly-Ile. Type IV collagenase showed essentially the same order of preference for the peptide substrates as did interstitial collagenase. Both required a peptide with a minimum of six amino acid residues to demonstrate significant gelatinolytic activity and were able to cleave uncharged molecules more rapidly than charged molecules. the repeating Gly-X-Y-Gly sequence of collagen is not an absolute requirement for either enzyme since both digested AcPro-Leu-Gly-Ile-Leu-Ala-Ala-OC2H5 at 70% of the rate of the best substrate peptide, AcPro-Leu-Gly-Leu-Leu-Gly-OC2H5. Km and kcat (Vmax) values were determined for several of the peptides and for the native substrate. Turnover numbers with type IV collagenase were similar to those with interstitial collagenase (Weingarten, H., Martin, R., and Feder, J. (1985) Biochemistry 24, 6730-6734). However, the Km for all peptides investigated was approximately 10-fold lower for type IV collagenase than for interstitial collagenase. Because type IV collagenase does not cleave helical interstitial collagens, the data support the conclusion that secondary structure determines whether the peptide bond can be hydrolyzed at any potential cleavage site.

Intravenous labetalol for the treatment of hypertension after carotid endarterectomy

Hypertension after carotid endarterectomy has a variable incidence ranging up to 56%. Blood pressure (BP) control is essential due to possible increased risk of morbidity from neurologic deficits or cardiovascular complications. This study evaluated intravenous labetalol for control of hypertension after carotid endarterectomy. Sixty ASA II-IV patients were studied; 20 developed BP high enough for treatment with labetalol. The anesthetic technique was standardized. Labetalol was administered at the conclusion of surgery as a 20-mg bolus over two minutes followed by 40 mg every 10 minutes until the desired BP was achieved (BP less than or equal to 10% above average preoperative BP or less than 150 mmHg, systolic) or 300 mg had been given. The mean total dose of labetalol was 42.0 +/- 33.0 mg (mean +/- SD) and mean time to reach the desired BP was 16.2 +/- 21.4 minutes. Systolic, diastolic, mean arterial pressure and heart rate significantly decreased after labetalol treatment and remained so for the remainder of the 180-minute study period. There was no hypotension, bradycardia, evidence of myocardial ischemia or central nervous system dysfunction present with labetalol treatment. Blood samples were obtained for determination of plasma renin activity, epinephrine, and norepinephrine in 10 patients who developed hypertension and received labetalol, and 10 patients who did not develop hypertension. In the patients developing hypertension, there was a significant elevation in epinephrine just before treatment, that decreased by 30 minutes after treatment. Norepinephrine levels became significantly elevated five minutes after labetalol treatment in the group with hypertension and remained elevated for 120 minutes. Concomitantly, there was a significantly lower plasma renin activity seen in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of tracheal intubating conditions and neuromuscular blocking profiles after intubating doses of mivacurium chloride or succinylcholine in surgical outpatients

Thirty ASA physical status I or II outpatients scheduled to undergo short procedures (less than 1 hr in duration) requiring tracheal intubation received either 1.0 mg/kg succinylcholine or 0.20 mg/kg (2.5 x ED95) or 0.25 mg/kg (3 x ED95) mivacurium. A N2O/O2/narcotic anesthetic technique was utilized and the ulnar nerve was stimulated with subcutaneous electrodes placed at the wrist. Tracheal intubation was attempted in all patients either 2 min after mivacurium or 1 min after succinylcholine. Intubation conditions were not different between the succinylcholine and mivacurium groups or between the two mivacurium groups. The onset and duration of neuromuscular blockade were shorter with succinylcholine than with mivacurium. Suppression of the T1 response to 90% of baseline occurred in 0.9 min with 1.0 mg/kg succinylcholine and at 2.2 and 1.5 min respectively, with 0.20 mg/kg and 0.25 mg/kg mivacurium. Initial recovery of the T1 response occurred at 6.4 min after 1.0 mg/kg succinylcholine and 12.7 and 13.6 min respectively after 0.20 mg/kg and 0.25 mg/kg mivacurium. Subsequent to initial recovery from the intubating dose of relaxant, infusions of mivacurium or succinylcholine were administered to maintain approximately 95% block. The mean infusion rates were 6.6 micrograms.kg-1.min-1 mivacurium and 41.2 micrograms.kg-1.min-1 for succinylcholine. Spontaneous recovery from neuromuscular blockade occurred more quickly after succinylcholine than after mivacurium: the time from cessation of infusion to recovery of T1 to 95% of baseline was 6.5 min in patients given succinylcholine and 16.7 min in patients given mivacurium. When reversal was in order, residual mivacurium-induced blockade was readily antagonized by 0.045 mg/kg neostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)

A dose-response evaluation of pipecuronium bromide in elderly patients under balanced anesthesia

Pipecuronium bromide is a new steroidal non-depolarizing muscle relaxant currently under investigation. It is similar to pancuronium with respect to the duration of action, but lacking its cardiovascular side effects. We examined the dose-response relation of pipecuronium in 27 patients, ages 66-79 years, utilizing the incremental dose method under balanced anesthesia. The ED50, ED90 and ED95 were 22.42 (5.2) mcg/kg, 31.81 (6.9) mcg/kg and 35.12 (7.8) mcg/kg, respectively (log probit method). Our recovery data also demonstrate that residual neuromuscular blockade due to pipecuronium can easily be antagonized with neostigmine as long as spontaneous recovery of T1- at the time of reversal administration is greater than 13%. The authors conclude that under balanced anesthesia the cumulative dose-response of pipecuronium in the elderly patients is consistent with those previously described for younger population. Therefore, no dose adjustment appears necessary for the elderly. However, as with all medications, careful administration is appropriate.

Clinical pharmacology of pipecuronium bromide

The neuromuscular blocking and cardiovascular effects of pipecuronium, in doses ranging 2-3 times its ED95, were evaluated in 46 patients during thiopental, fentanyl, N2O/O2 anesthesia. The neuromuscular blocking effect of pipecuronium was evaluated by recording of the mechanical twitch of the adductor pollicis muscle in response to stimulation of the ulnar nerve at the wrist. Heart rate, systolic and diastolic blood pressures, and cardiac output were non-invasively measured during the onset of the neuromuscular blockade and compared to a saline control group to separate the effect of anesthesia from those of pipecuronium. The mean +/- SD time from administration of pipecuronium to 90% suppression of the first twitch (T1) of the train-of-four was 2.6 +/- 0.8, 2.0 +/- 0.6, and 2.1 +/- 0.6 min following the 70 micrograms/kg, 85 micrograms/kg, and 100 micrograms/kg dose, respectively. There was no significant difference between the different doses of pipecuronium in the time to 90% suppression of T1. In general, all three doses of pipecuronium provided good to excellent intubating conditions within 3 minutes after its administration. The time from the administration of pipecuronium to 5% recovery of T1 was 52.3 +/- 18.2 min in the group given 70 micrograms/kg. This was significantly longer in patients given 85 micrograms/kg (71.9 +/- 15.7 min) or 100 micrograms/kg (71.8 +/- 22.1 min). Times to the start of recovery of T1 and to 25% recovery of T1 showed a similar significant pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Cleavage of type VII collagen by interstitial collagenase and type IV collagenase (gelatinase) derived from human skin

Type VII collagen is the major structural protein of anchoring fibrils, which are believed to be critical for epidermal-dermal adhesion in the basement membrane zone of the skin. To elucidate possible mechanisms for the turnover of this protein, we examined the capacities of two proteases, human skin collagenase, which degrades interstitial collagens, and a protease with gelatinolytic and type IV collagenase activities, to cleave type VII collagen. At temperatures below the denaturation temperature, pepsin cleaves type VII collagen into products of approximately 95 and approximately 75 kDa. Human skin collagenase cleaved type VII collagen into two stable fragments of approximately 83 and approximately 80 kDa, and the type IV collagenase (gelatinase) produced a broad band of approximately 80 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cleavage of type VII collagen was linear with time and enzyme concentration for both enzymes. Although the Km values were similar for both enzymes, the catalytic rate of cleavage by type IV collagenase is much faster than by interstitial collagenase, and shows a greater rate of increase with increasing temperature. Sequence analysis of the cleavage products from both enzymes showed typical collagenous sequences, indicating a relaxation in the helical part of the type VII collagen molecule at physiological temperature which makes it susceptible to gelatinolytic degradation. Interstitial collagenase from both normal skin cells and cells from patients with recessive dystrophic epidermolysis bullosa, a severe hereditary blistering disease in which both an anchoring fibril defect and excessive production of collagenase can be observed, produced identical cleavage products from type VII collagen. These data suggest a pathophysiological link between increased enzyme levels and the observed decrease or absence of anchoring fibrils.

Effect of myocardial revascularization and vein graft blood flow on pacing function

The effect of myocardial revascularization and vein graft blood flow on pacing function was determined in nine patients undergoing aortocoronary bypass. Pacing variables including threshold, current, and resistance were measured with a pacing system analyzer during intermittent pacing with a transluminal bipolar ventricular pacing probe. Pacing function was analyzed immediately before cardiopulmonary bypass (CPB) and compared with measurements taken eight minutes after full flow through the vein grafts had been established. Comparison of these two times showed a significant decrease in resistance, P < 0.003, and threshold, P < 0.03. After the second measurement, left anterior descending (n = 8), or right coronary (n = 1) vein graft blood flow was interrupted. Pacing variables were analyzed at one minute, two minutes, and four minutes following vein graft clamping; and a final set of measurements was obtained one minute following release of the vein graft clamp. Threshold increased but did not reach statistical significance. Resistance increased significantly: P < 0.03. All values returned to baseline following release of the vein graft clamp and full return of blood flow. The results of this study suggest that pacing function measurements are sensitive to changes in vein graft blood flow and may provide useful information about the condition of the myocardium, especially immediately prior to weaning from CPB.

H-ras oncogene-transformed human bronchial epithelial cells (TBE-1) secrete a single metalloprotease capable of degrading basement membrane collagen

H-ras-transformed human bronchial epithelial cells (TBE-1) secrete a single major extracellular matrix metalloprotease which is not found in the normal parental cells. The enzyme is secreted in a latent form of 72 kDa, which can be activated to catalyze the cleavage of the basement membrane macromolecule type IV collagen. The substrates in their order of preference are: gelatin, type IV collagen, type V collagen, fibronectin, and type VII collagen; but the enzyme does not cleave the interstitial collagens or laminin. This protease is identical to gelatinase isolated from normal human skin explants, normal human skin fibroblasts, and SV40-transformed human lung fibroblasts. Based on its ability to initiate the degradation of type IV collagen in a pepsin-resistant portion of the molecule, it will be referred to as type IV collagenase. This enzyme is most likely the human analog of type IV collagenase detected in several rodent tumors, which has the same molecular mass and has been linked to their metastatic potential. Type IV collagenase consists of three domains. Two of them, the amino-terminal domain and the carboxyl-terminal domain, are homologous to interstitial collagenase and human and rat stromelysin. The middle domain, of 175 residues, is organized into three 58-residue head-to-tail repeats which are homologous to the type II motif of the collagen-binding domain of fibronectin. Type IV collagenase represents the third member of a newly recognized gene family coding for secreted extracellular matrix metalloproteases, which includes interstitial fibroblast collagenase and stromelysin.

Prostacyclin mediation of vasodilation following mesenteric traction

Eight untreated patients (group I) and four patients who received ibuprofen preoperatively (group II) scheduled for elective abdominal aortic aneurysm repair were studied. Heart rate (HR); systolic, diastolic, and mean arterial pressure (MAP); systolic and diastolic pulmonary artery pressure; pulmonary capillary wedge pressure (PCWP); cardiac output (CO); and central venous pressure (CVP) were recorded pre-induction, before mesenteric traction, and 5, 15, and 30 min post-mesenteric traction. Plasma samples were obtained at these times for analysis of six-keto-prostaglandin F1 alpha (PGF1 alpha) concentration by radioimmunoassay. Group II patients received ibuprofen 12 mg/kg orally 1 1/2 h before surgery. Plasma samples from six group I patients and all group II patients taken 5 min after mesenteric traction were added to isolated helical strips of cat superior mesenteric arteries precontracted with norepinephrine (200 ng/ml) for analysis of reduction in developed force. In group I, abdominal mesenteric traction resulted in a significant decrease in MAP (P less than 0.03) and SVR (P less than 0.005) with an increase in CO (P less than 0.05) at 5 min post-mesenteric traction, which returned to mean pre-mesenteric traction values by 30 min and a significant increase in PGF1 alpha concentrations. There was a significant positive correlation between PGF1 alpha and CO (P less than 0.001) and a significant negative correlation between PGF1 alpha and SVR (P less than 0.01) at 5 min post-mesenteric traction.(ABSTRACT TRUNCATED AT 250 WORDS)

Eriochrome black T inhibition of human skin collagenase, but not gelatinase, using both protein and synthetic substrates

The intracellular degradation of interstitial collagen is accomplished by two neutral metalloproteases, collagenase and gelatinase. Both enzymes are inhibited by metal chelating agents, by certain sulfhydryl reagents, and by similar protein inhibitors. Here, we demonstrate that the dye eriochrome black T (EBT) appears to be unique in its capacity to inhibit collagenase but not gelatinase. Using native reconstituted helical collagen in gel form at 37 degrees C, half-maximal inhibition of collagenase activity by EBT occurs at approximately 45 microM. EBT more effectively inhibits the breakdown of native collagen in solution, with a KI of approximately 8 microM. Using a newly-developed spectrophotometric substrate, AcProLeuGly-S-LeuLeuGly-OC2H5, a KI of 1.4 microM was calculated for EBT on collagenase. Although this same thiopeptolide serves as a substrate for gelatinase with kinetics similar to those of collagenase, no inhibition by EBT was observed. EBT also did not inhibit the gelatinase-mediated breakdown of the natural substrate, gelatin. The data suggest that EBT may have significant potential for allowing the differentiation in biological fluids of two metalloproteases with similar cleavage site specificities.

The lack of response to suggestion under controlled surgical anesthesia

Thirty-two ASA I or II women undergoing abdominal hysterectomy were randomly allocated to four groups to determine what type, if any, of recorded intraoperative message they would receive. Groups I and II heard a neutral recording with no verbal content. Group III heard an experimental recording with a positive suggestion for a rapid recovery. Group IV had a self-prepared message. The tapes were played during general anesthesia when anesthetic depth was judged to be stable and adequate by vital signs, end-tidal anesthetic concentration and EEG compressed spectral array. No patient reported any recall of intraoperative messages when interviewed on the day after surgery. Chart review showed no difference in days of hospitalization, dose of analgesics required, time to beginning oral intake, or the amount of wound drainage (P greater than 0.05). We conclude that no awareness can be observed directly by recall or indirectly by response to suggestion given under stable and adequate general anesthesia.

Pain control for the urologist

Pain states can be divided into three categories: acute, chronic not resulting from malignancy, and chronic malignant pain. A Pain Clinic can provide in-depth evaluation and treatment of difficult pain problems. A variety of oral and parenteral medications, ranging from nonsteroidal analgesics to narcotics, are available to control pain. Local anesthetics can be used for local infiltration, and peripheral and central nerve blocks can also be used as indications warrant.