Operating room efficiency of orthopedic surgery during the COVID-19 era.

OBJECTIVE: The COVID-19 pandemic forced operating rooms (ORs) to adopt new safety protocols. Although these measures protected the health of patients and providers, their impact on OR efficiency remains unclear. Our objective was to further elucidate the effects of COVID-19 on orthopedic surgery OR efficiency. STUDY DESIGN: This was a retrospective study of 14,856 orthopedic surgeries performed between December 1, 2019, and October 31, 2021. METHODS: Institutional perioperative databases were used to identify relevant orthopedic surgeries. The onset of the COVID-19 period was set as March 12, 2020, when a state of emergency was declared in Tennessee. Both 90-day periods before and after this date were used for comparative analysis of the pre-COVID-19, peak-restrictions, and post-peak-restrictions time periods. Delay of first case start time and turnover time between cases were used as primary measures of efficiency. RESULTS: There were 1853 pre-COVID-19 cases, 1299 peak-restrictions cases, and 11,704 post-peak-restrictions cases analyzed. Delay of first case start time was found to be significantly different among the time periods (mean [SD] minutes, 7 [14] vs 8 [18] vs 7 [17], respectively; P < .001). Turnover time between cases was also significantly different among the time periods (62 [49] vs 66 [51] vs 64 [51]; P = .002). CONCLUSIONS: Although significant, there was minimal absolute change in orthopedic OR efficiency during the onset of the pandemic. These results suggest that the protocols enacted at our institution appropriately maintained orthopedic OR efficiency, even in the context of the rapidly increasing COVID-19 burden.

The cost of a plastic surgery team assisting with cranioplasty.

OBJECTIVES: Cranioplasty is a commonly performed neurosurgical procedure that restores cranial anatomy. While plastic surgeons are commonly involved with cranioplasties, the cost of performing a cranioplasty with neurosurgery alone (N) vs. neurosurgery and plastic surgery (N + P) is unknown. METHODS: A single-center, multi-surgeon, retrospective cohort study was undertaken on all cranioplasties performed from 2012 to 22. The primary exposure variable of interest was operating team, comparing N vs. N + P. Cost data was inflation-adjusted to January 2022 using Healthcare Producer Price Index as calculated by the US Bureau of Labor Statistics. RESULTS: 186 patients (105 N vs. 81 N + P) underwent cranioplasties. The N + P group has a significantly longer length-of-stay (LOS) 4.5 ± 1.6days, vs. 6.0 ± 1.3days (p < 0.001), but no significant difference in reoperation, readmission, sepsis, or wound breakdown. N was significantly less expensive than N + P during both the initial cranioplasty cost ($36,739 ± $4592 vs. $41,129 ± $4374, p 0.014) and total cranioplasty costs including reoperations ($38,849 ± $5017 vs. $53,134 ± $6912, p < 0.001). Univariable analysis (threshold p = 0.20) was performed to justify inclusion into a multivariable regression model. Multivariable analysis for initial cranioplasty cost showed that sepsis (p = 0.024) and LOS (p = 0.003) were the dominant cost contributors compared to surgeon type (p = 0.200). However, surgeon type (N vs. N + P) was the only significant factor (p = 0.011) for total cost including revisions. CONCLUSIONS: Higher costs to N + P involvement without obvious change in outcomes were found in patients undergoing cranioplasty. Although other factors are more significant for the initial cranioplasty cost (sepsis, LOS), surgeon type proved the independent dominant factor for total cranioplasty costs, including revisions.

The hemodynamics of oxytocin and other vasoactive agents during neuraxial anesthesia for cesarean delivery: findings in six cases.

Oxytocin is a commonly used uterotonic that can cause significant and even fatal hypotension, particularly when given as a bolus. The resulting hypotension can be produced by a decrease in systemic vascular resistance or cardiac output through a decrease in venous return. Parturients with normal volume status, heart valves and pulmonary vasculature most often respond to this hypotension with a compensatory increase in heart rate and stroke volume. Oxytocin-induced hypotension at cesarean delivery may be incorrectly attributed to blood loss. Pulse power analysis (also called "pulse contour analysis") of an arterial pressure wave form allows continuous evaluation of systemic vascular resistance and cardiac output in real time, thereby elucidating the causative factors behind changes in blood pressure. Pulse power analysis was conducted in six cases of cesarean delivery performed under neuraxial anesthesia. Hypotension in response to oxytocin was associated with a decrease in systemic vascular resistance and a compensatory increase in stroke volume, heart rate and cardiac output. Pulse power analysis may be helpful in determining the etiology of and treating hypotension during cesarean delivery under neuraxial anesthesia.

PFA-100 system: a new method for assessment of platelet dysfunction.

The PFA-100 system is a platelet function analyzer designed to measure platelet-related primary hemostasis. The instrument uses two disposable cartridges: a collagen/epinephrine (CEPI) and a collagen/ADP (CADP) cartridge. Previous experience has shown that CEPI cartridges detect qualitative platelet defects, including acetylsalicylic acid (ASA)-induced abnormalities, while CADP cartridges detect only thrombocytopathies and not ASA use. In this seven-center trial, 206 healthy subjects and 176 persons with various platelet-related defects, including 127 ASA users, were studied. The platelet function status was determined by a platelet function test panel. Comparisons were made as to how well the defects were identified by the PFA-100 system and by platelet aggregometry. The reference intervals for both cartridges, testing the 206 healthy subjects, were similar to values described in smaller studies in the literature [mean closure time (CT) 132 s for CEPI and 93 s for CADP]. The use of different lot numbers of cartridges or duplicate versus singleton testing revealed no differences. Compared with the platelet function status, the PFA-100 system had a clinical sensitivity of 94.9% and a specificity of 88.8%. For aggregometry, a sensitivity of 94.3% and a specificity of 88.3% were obtained. These values are based on all 382 specimens. A separate analysis of sensitivity by type of platelet defect, ASA use versus congenital thrombocytopathies, revealed for the PFA-100 system a 94.5% sensitivity in identifying ASA users and a 95.9% sensitivity in identifying the other defects. For aggregometry, the values were 100% for ASA users and 79.6% for congenital defects. Analysis of concordance between the PFA-100 system and aggregometry revealed no difference in clinical sensitivity and specificity between the systems (p > 0.9999). The overall agreement was 87.5%, with a Kappa index of 0.751. The two tests are thus equivalent in their ability to identify normal and abnormal platelet defects. Testing 126 subjects who took 325 mg ASA revealed that the PFA-100 system (CEPI) was able to detect 71.7% of ASA-induced defects with a positive predictive value of 97.8%. The overall clinical accuracy of the system, calculated from the area under the ROC curve, was 0.977. The data suggest that the PFA-100 system is highly accurate in discriminating normal from abnormal platelet function. The ease of operation of the instrument makes it a useful tool to use in screening patients for platelet-related hemostasis defects.

Mammalian recombinant coagulation proteins: structure and function.

Recombinant DNA technology has permitted the production of synthetic proteins which are potentially free of human infectious agents. Despite production in foreign cells, these proteins are structurally and functionally comparable to the native proteins. Recombinant clotting factors VIII, IX, VIIa, and von Willebrand factor have the same primary sequence as their plasma counterparts. The secondary and tertiary structures are similar, Post-translational modifications, including proteolytic processing, disulfide bonding, addition and processing of N- and O-linked glycans, gamma-carboxylation of glutamic acid residues, beta-hydroxylation of aspartic acid residues, sulfation of tyrosine residues, and phosphorylation of serine residues, are similar but not always identical, In some instances. these differences may cause significant functional differences. For example, reduced tyrosine sulfation and serine phosphorylation of recombinant factor IX have been correlated with reduced recovery following intravenous infusion. The specific clotting activity of the recombinant factors, an indication of their coagulant function, is equivalent to that of the plasma factors. Finally, these proteins have been used clinically and shown to correct clinical deficiencies of these proteins in a manner that is similar to replacement with plasma factors. All in all, the promise of recombinant DNA technology for coagulation and other disorders remains bright.

Successful treatment of transient acquired factor X deficiency by plasmapheresis with concomitant intravenous immunoglobulin and steroid therapy.

Two patients with no history of previous bleeding diatheses presented with active bleeding from multiple body sites, declining hemoglobin levels, and markedly prolonged prothrombin times (PT) and activated partial thromboplastin times (aPTT) with incomplete correction on PT mix assays. Both patients demonstrated a severe deficiency of factor X (F.X) (<1%; reference range 60-150%). F.X levels and bleeding were refractory to multiple transfusions of fresh frozen plasma (FFP) in both patients. In contrast, daily therapeutic plasma exchange (PLEX) with concomitant administration of intravenous immunoglobulin (IV IgG) and steroids produced a rapid increase in F.X levels with cessation of bleeding, followed by stabilization and normalization of F.X levels and progressive correction of coagulation times. Neither patient has demonstrated a recurrence of the bleeding tendency following discontinuation of steroid therapy. These patients had transient acquired F.X deficiency, a rare coagulopathy, which can result in a lethal bleeding diathesis. An IgG inhibitor that selectively inhibited F.X activation in Russell's viper venom or tissue factor/F.VIIa assays was demonstrated in one patient's pretreatment plasma. Previous treatment of hemorrhage in transient acquired F.X deficiency has been prothrombin complex and/or activated clotting concentrates, which can be associated with transient hypercoagulable states. This is the first reported use of PLEX in transient acquired F.X deficiency. PLEX is safe, efficacious, and rapidly restores hemostasis in this rare acquired bleeding disorder.

Cloning, expression, and characterization of mouse tissue factor pathway inhibitor (TFPI).

Tissue factor pathway inhibitor (TFPI) acts to regulate the initiation of coagulation by first inhibiting factor Xa. The complex of factor Xa/TFPI then inhibits the factor VIIa/tissue factor complex. The cDNA sequences of TFPI from several different species have been previously reported. A high level of similarity is present among TFPIs at the molecular level (DNA and protein sequences) as well as in biochemical function (inhibition of factor Xa, VIIa/tissue factor). In this report, we used a PCR-based screening method to clone cDNA for full length TFPI from a mouse macrophage cDNA library. Both cDNA and predicted protein sequences show significant homology to the other reported TFPI sequences, especially to that of rat. Mouse TFPI has a signal peptide of 28 amino acid residues followed by the mature protein (in which the signal peptide is removed) which has 278 amino acid residues. Mouse TFPI, like that of other species, consists of three tandem Kunitz type domains. Recombinant mouse TFPI was expressed in the human kidney cell line 293 and purified for functional assays. When using human clotting factors to investigate the inhibition spectrum of mouse TFPI, it was shown that, in addition to human factor Xa, mouse TFPI inhibits human factors VIIa, IXa, as well as factor XIa. Cloning and expression of the mouse TFPI gene will offer useful information and material for coagulation studies performed in a mouse model system.

Assessment of platelet activation by coronary sinus blood sampling during balloon angioplasty and directional coronary atherectomy.

Three markers of platelet activation (platelet-derived microparticles, fibrinogen binding and expression of P-selectin) were assessed by flow cytometry during diagnostic coronary angiography and therapeutic coronary interventions. In 24 patients undergoing diagnostic angiography, blood was collected to determine if our sampling techniques or coronary angiography caused platelet activation. Changes during diagnostic angiography were used to establish baseline values and interpret changes during coronary interventions. In 21 patients, blood samples were obtained at 5 time points during percutaneous transluminal coronary angioplasty (PTCA) (n = 17) or directional coronary atherectomy (DCA) (n = 4). During coronary interventions, mean values for the percentage of platelets expressing P-selectin or binding fibrinogen increased, but with considerable variation among patients. Individual responses for platelet activation markers in each patient were characterized using a twofold increase to indicate elevation related to the intervention. Patients were classified as having complicated or uncomplicated procedures based on the presence of acute closure, dissection, or thrombus observed by angiography. There were no differences in the percentage of elevated markers between patients with uncomplicated (12.5%) and complicated (19%) PTCA procedures. However, patients treated with DCA had more elevated markers (38%) than those treated with PTCA (15%) (p = 0.04). Our data suggest that the extent of platelet activation in individual patients cannot be predicted by common angiographic findings or complications. More markers of platelet activation were present after DCA and may reflect a greater degree of vascular trauma associated with this procedure.

Precipitous fall in platelet count with anagrelide: case report and critique of dosing recommendations.

Thrombotic and hemorrhagic events may result from high circulating concentrations of platelets (> 1,000,000/mm3), and measures to reduce the platelet count are indicated in symptomatic or extreme thrombocytosis. The platelet count can be decreased quickly by plasmapheresis, but the effect is transient. Patients with thrombocytosis secondary to a myeloproliferative disease, such as chronic myelogenous leukemia (CML), frequently require more sustained suppression of the platelet count. Hydroxyurea, busulfan, and interferon are used to maintain a lower platelet count but are occasionally ineffective or intolerable. An alternative to these therapies is anagrelide, a quinazolin derivative that was approved by the Food and Drug Administration in March 1997. Because current dosing guidelines for anagrelide are scarce, the dosing method of the Anagrelide Study Group that published the largest study to date on the drug's efficacy in thrombocytosis was followed. Two unexpected episodes of anagrelide-induced thrombocytopenia occurred despite following these dosing methods. This prompted a critical evaluation of the pharmacodynamic response and the appropriateness of anagrelide dosage recommendations. A case of thrombocytosis treated with anagrelide in a patient with CML is described.

Extravascular administration of factor IX: potential for replacement therapy of canine and human hemophilia B.

Current therapy for hemophilia B requires large intravenous doses of factor IX (F.IX) given in the clinic or at home. Although home therapy is possible for many patients, it is often complicated by factors such as the lack of good venous access. Very little is known about extravascular routes for administering proteins like F.IX (57 kD) or other vitamin K-dependent procoagulant factors into the circulation. Questions about the absorption rate from extravascular administration as well as plasma recovery and bioavailability have arisen recently with the growing availability of highly purified procoagulant proteins and increased interest in gene therapy of hemophilia B. Therefore, a group of studies were undertaken to determine the absorption rate, plasma recovery, and bioavailability of high purity, human plasma-derived F.IX concentrates administered via extravascular routes in hemophilia B dogs and in one human hemophilia B subject. Five hemophilia B dogs were given human F.IX via either a subcutaneous (s.c.), intramuscular (i.m.), intraperitoneal (i.p.) or intravenous (i.v.) route. In a subsequent study, a single SC administration of human F.IX was compared to an identical i.v. dose of F.IX in the human hemophilia B subject. All extravascular routes of F.IX administration in both the canine and human gave lower levels of circulating plasma F.IX than the i.v. route, however all routes resulted in measurable F.IX activity. Of the extravascular routes, the i.m. injection in the canine resulted in a bioavailability of 82.8%, while the s.c. injection resulted in a bioavailability of 63.5%. F.IX reached the plasma compartment by all extravascular routes used, confirming that F.IX can be absorbed extravascularly. The duration of measurable F.IX activity following extravascular administration is prolonged beyond that typically seen with i.v. administration. These data show that significant levels of F.IX may be obtained via s.c. injection in canine and human hemophilia B subjects and further highlight the potential of extravascular routes of administration for future experimental and clinical uses of F.IX and other procoagulant proteins.

Results of dorsal wrist synovectomies in the rheumatoid hand.

Seventy-eight patients with rheumatoid arthritis had 102 dorsal wrist tenosynovectomies, intraarticular synovectomies, and Darrach resection from 1962 to 1982. Follow-up after surgery averaged 11 years, with a range from 3 to 20 years. Pain was diminished in all but 17 wrists and motion decreased an average of 13 degrees. Synovitis recurred in 16 wrists and x-ray evidence of progressive intraarticular destruction was seen in 45 wrists. Revision surgery was necessary in 28 wrists.

Needle aspiration for diagnosis of cellulitis.

Diagnosing the causative agent of bacterial cellulitis is difficult. Blood culturing and needle aspiration have been used: the former has an extremely low sensitivity, the yield of the latter ranges from 4 to 42 percent. A retrospective study was conducted to determine the diagnostic success of needle aspiration and culture of the leading edge of cellulitis with a 21 to 22 gauge syringe and conventional bacteriologic culture of blood in determining the agent that causes acute cellulitis. This agent was determined in 33 percent of patients by needle aspiration and in 4 percent using blood cultures.