Toshiyuki Sawai

Perioperative risk factors for deep vein thrombosis after total hip arthroplasty or total knee arthroplasty

STUDY OBJECTIVE To determine the perioperative frequency of deep vein thrombosis (DVT) after lower limb joint prosthesis surgery using Doppler ultrasonography (US). DESIGN Prospective cohort study. SETTING Operating room and hospital ward. PATIENTS 144 consecutive ASA physical status 1 and 2 patients who underwent elective total hip arthroplasty (THA; n=64) or total knee arthroplasty (TKA; n= 80). INTERVENTIONS Patients were allocated to two groups, those who developed DVT (DVT group) postoperatively and those who did not (no-DVT group). To examine the perioperative risk factors for DVT after THA or TKA, comparative analysis of the two groups was done. MEASUREMENTS Doppler US was performed on all patients from the bilateral femoral to lower limb to detect the existence of DVT postoperatively. MAIN RESULTS DVT was detected in 61 patients (42%), including three proximal DVT patients (2%). Preoperative elevated plasma D-dimer value [P = 0.0131, odds ratio (OR) 1.54, 95% CI 1.10-2.17] and history of hyperlipidemia (P = 0.0453, OR 6.92, 95% CI 1.04-46.00] were significant risk factors for the onset of DVT. A preoperative plasma D-dimer cutoff value as a diagnostic test was obtained as 0.85 μg/mL. CONCLUSIONS A high preoperative plasma D-dimer value and/or history of hyperlipidemia were risk factors for DVT after THA or TKA.

Correlation between extraction force during tracheal intubation stylet removal and postoperative sore throat

STUDY OBJECTIVE To examine postoperative sore throat resulting from tracheal intubation stylet removal. DESIGN Prospective cohort study. SETTING Operating rooms and hospital ward. PATIENTS A total of 50 American Society of Anesthesiologists physical status 1 and 2 patients who underwent elective abdominal and/or orthopedic surgery under general anesthesia. INTERVENTIONS Patients were allocated to 2 groups: those who developed sore throat postoperatively (ST group) and those who did not (NST group). Comparative analysis of these 2 groups was performed to identify risk factors of the development of sore throat. MEASUREMENTS The extraction force during stylet removal was measured using a force measuring device. Postoperative sore throat was assessed by an anesthesiologist. MAIN RESULTS Nine patients (18%) complained of postoperative sore throat. Increased extraction force (P=.0054; odds ratio, 1.84; 95% confidence interval, 1.20-2.84) was the only significant risk factor for the development of postoperative sore throat. An extraction force of >10.3N was determined as a cutoff for developing postoperative sore throat. CONCLUSION Postoperative sore throat was significantly related to increased extraction force during stylet removal.

Lambl's excrescence on aortic valve detected by transesophageal echocardiography

A 69-yr-old woman was scheduled for mitral valve replacement and coronary artery bypass graft surgery. Her medical history included mitral stenosis and a single coronary artery disease. She was given anticoagulation therapy for paroxysmal atrial fibrillation. Preoperative transthoracic echocardiography demonstrated mitral stenosis and trivial aortic regurgitation but no abnormal intracardiac structures. After induction of general anesthesia, we placed a transesophageal multiplane probe (Philips Electronics, Eindhoven, Netherlands). Two dimensional transesophageal echocardiography (TEE) confirmed doming and calcification of the mitral valve. Color flow Doppler imaging in the midesophageal longand shortaxis views demonstrated a trivial eccentric jet of aortic regurgitation from the commissure between the right and left coronary cusp. The midesophageal long-axis view showed the presence of a filamentous structure on the aortic valve (AV), which was not noticed by the preoperative transthoracic echocardiography. The structure was very thin, approximately 10-mm long, and was flapping in the aortic root (Figs. 1A and B), (Video clip 1; please see video clip available at www.anesthesia-analgesia.org). We first performed mitral valve replacement with a mechanical valve from the right atrium via the atrial septum. Second, we performed coronary artery bypass to the left anterior descending branch with the left internal thoracic artery. Third, we opened the ascending aorta to observe the flapping structure. The structure was attached to the free edge of the left coronary cusp. We decided to resect it to avoid systemic embolization and to confirm the diagnosis. The structure was a 12-mm fibrous tissue (Fig. 2). We presumed it was a flapping piece torn from the commissure between the right and left coronary cusp along the edge of the left coronary cusp. Because pathological examination revealed that the structure consisted of connective tissue covered by a single layer of endothelial cells, we diagnosed Lambl’s excrescence. After uneventful weaning from cardiopulmonary bypass, subsequent TEE confirmed that the filamentous structure on the AV was no longer present and the degree of aortic regurgitation remained trivial. The differential diagnoses of the flapping structure in the AV included imaging artifact, vegetation, thrombus, redundant leaflet, flap due to aortic dissection, papillary fibroelastoma, and Lambl’s excrescence. The TEE imaging from multiple planes excluded a possibility of imaging artifact. We easily excluded the diagnosis of vegetation, because inflammatory findings and a history of infections endocarditis were absent. We also excluded thrombus because the structure was very thin and filamentous. We dismissed the possibility of a redundant leaflet or a flap due to aortic dissection, because three cusps of the AV were depicted clearly by TEE. The distinction between papillary fibroelastoma and Lambl’s excrescence was particularly difficult. Papillary fibroelastoma typically appears on echocardiography as a small pedunculated, homogenous, well-demonstrated mobile mass attached by a small stalk. Although these findings may be applied to Lambl’s excrescence, the stalk of papillary fibroelastoma has a broader base This article has supplementary material on the Web site: www.anesthesia-analgesia.org.

Cardiac output measurement using the transesophageal doppler method is less accurate than the thermodilution method when changing Paco2

Cardiac output (CO) determination using transesophageal Doppler is based on the measurement of descending aortic blood flow. Because cerebral blood flow is dependent on Paco2, an increase in Paco2 would result in an increase of CO because of the increase in cerebral blood flow and vice versa. We enrolled 30 patients undergoing off-pump coronary artery graft surgery in the study. The CO was determined by both transesophageal Doppler and thermodilution while Paco2 was maintained at either 30 mm Hg or 40 mm Hg in random order. The CO by thermodilution was significantly higher at Paco2 of 40 mm Hg (4.17 ± 0.94 L/min) than at 30 mm Hg (3.78 ± 0.85 L/min). On the other hand, there were no significant differences in CO by transesophageal Doppler: 3.85 ± 0.76 L/min at Paco2 of 40 mm Hg and 3.77 ± 0.74 at 30 mm Hg. Bland-Altman analysis yielded bias and precision of −0.32 and 0.49 L/min at Paco2 of 40 mm Hg, and −0.01 and 0.34 L/min at 30 mm Hg. These results indicate that both methods of CO measurement are in agreement at 30 mm Hg of Paco2, but the thermodilution method provides higher values at 40 mm Hg of Paco2.

A Perioperative Evaluation of Respiratory Mechanics Using the Forced Oscillation Technique.

BACKGROUND:The forced oscillation technique is a new approach for assessing perioperative respiratory function. METHODS:This study enrolled 40 patients undergoing general anesthesia: 20 for ≥2 hours and 20 for <2 hours. Respiratory parameters were measured the day before and after surgery using forced oscillation during normal tidal breathing. RESULTS:Respiratory resistance at 5 Hz (P = 0.029 with the Student t test with unequal variances and P = 0.033 with analysis of covariance) changed significantly in the patients who underwent procedures for which they were anesthetized for >2 hours. CONCLUSIONS:The forced oscillation technique is a clinical tool that can be used to assess the effects of perioperative ventilation strategies on respiratory mechanics.

Unexpected hemorrhage during robot-assisted laparoscopic prostatectomy: a case report

BackgroundRobot-assisted laparoscopic prostatectomy is increasingly performed as a minimally invasive option for patients with organ-confined prostate cancer. This technique offers several advantages over other surgical methods. However, concerns have been raised over the effects of the steep head-down tilt necessary during the procedure. We present a case in which head-down positioning and abdominal insufflation masked the signs of an intraoperative hemorrhage.Case presentationA 73-year-old Asian man developed severe hypotension caused by an unexpected hemorrhage during robot-assisted laparoscopic prostatectomy for prostate cancer. Although our patient’s blood pressure steadily decreased during the procedure, his systolic blood pressure remained above 80 mmHg while he was tilted head downward at an angle of 28°. However, his blood pressure dropped immediately after he was returned to the horizontal position and abdominal insufflation – to create a pneumoperitoneum – was ceased at the end of surgery. We returned the patient to a head-down tilt to keep his blood pressure stable and began fluid infusion. Blood test results indicated that a hemorrhage was the cause of his hypotension. Open abdominal surgery was performed to stop the bleeding. The surgeons found blood pooling inside his abdomen from a longitudinal cut in a small arterial vessel in his abdominal wall, possibly a branch of his external iliac artery. The surgeons successfully controlled the hemorrhage and our patient was moved to our intensive care unit. Our patient recovered completely over the next few days, without any neurological deficits.ConclusionsWe suspect that blood began to pool in our patient’s superior abdomen during surgery, and that increased intra-abdominal pressure suppressed the hemorrhage. When our patient was returned to the horizontal position and insufflation of his abdomen was discontinued, the resulting increased rate of hemorrhage caused a sudden drop in blood pressure. Surgeons and anesthesiologists must understand the hemodynamic changes that result from head-down patient positioning and abdominal insufflation.

Elective use of intra-aortic balloon pump during aortic valve replacement in elderly patients to reduce postoperative cardiac complications.

This is a retrospective cohort study to determine if routine intra-aortic balloon pump (IABP) placement prior to aortic valve replacement in elderly patients with severe aortic stenosis without significant coronary artery stenosis reduces cardiac complications. Participants were patients aged ≥70 years without significant coronary stenosis, who had severe aortic stenosis, and were undergoing isolated aortic valve replacement. Our primary endpoint was postoperative cardiac morbidity rate as a composite of the adverse cardiac events: elevated creatine kinase with muscle and brain subunits (CK-MB)/CK (>5%), fatal ventricular arrhythmias requiring therapy, or catecholamine index of >10. Eighteen patients had elective IABP insertion prior to surgery, and 16 patients had no planned IABP insertion. One patient died (5.6%) in the elective IABP group (P = 1.0 compared with the non-IABP group). The overall rate of in-hospital death was 2.9% (1/34). In the non-IABP group, one patient had rescue IABP insertion after surgery (6.3%). The elective IABP group had a significantly lower cardiac morbidity rate than the non-IABP group (44.4 vs. 87.5%, respectively, P = 0.013). According to multivariate analysis using a logistic European system for cardiac operative risk evaluation value of >10% to define increased morbidity, elective IABP use significantly reduced cardiac morbidity (odds ratio, 0.11; 95% confidence interval, 0.02-0.67; P = 0.016). Additionally, the elective IABP group was more likely to show low CK-MB/CK than the non-IABP group (4.1 ± 1.9% vs. 6.1 ± 3.1%, respectively, P = 0.026). We concluded that among elderly aortic valve replacement patients without significant coronary artery stenosis, elective IABP use may reduce the incidence of major adverse cardiac events.

Pathologic Examination of Lambl’s Excrescence

We read with interest the article titled “Endovascular transcatheter aortic valve implantation: An evolving standard” published by Sfeir PM et al. In view of the greying of the population and the higher age of patients, severe aortic stenosis patients who undergo transcatheter aortic valve implantation are more likely to have Lambl’s excrescences than 10 years ago. Lambl’s excrescences are small, mobile valvular strands made up of connective tissue. They are thin (o1 mm), long (410 mm) filiform projections from heart valves that show undulating independent motion. They are more commonly seen on the mitral valve than on the aortic valve, typically near the closure line of the mitral valve. Although it was first reported that they were composed of fibrin, morphologic analysis revealed the presence of collagen. Several previous case reports have shown no common morphologic and histologic structures for Lambl’s excrescences. Here, we wish to share our experience of a patient with Lambl’s excrescence. We have included histologic images of the excrescence. While providing anesthesia for a patient undergoing mitral valve replacement surgery, we performed transesophageal echocardiography and found the Lambl’s excrescence on the aortic valve in the form of a 12-mm fibrous tissue (Fig 1). We presumed it was a flapping piece torn from the commissure between the right and left coronary cusps along the edge of the left coronary cusp. Pathologic examination of the tissue with hematoxylin eosin staining revealed that the structure consisted of connective tissue covered by a single layer of endothelial cells (Fig 2). Examination with Elastica Van Gieson’s stain showed that it had a collagenous structure with elastic fibers inside and was surrounded by loose connective tissue (Fig 3). Hence, it was diagnosed as a typical Lambl’s excrescence. Since these excrescences are similar in composition to cardiac valves, the strand was assumed to have come off the surface of the valve to which the strand was attached due to the flow of blood.

Intraoperative transesophageal echocardiography enables characterization of coronary artery fistula in coexistence with multiple giant coronary artery aneurysms.

A 35-yr-old healthy woman was admitted for evaluation of an abnormal cardiac mass on twodimensional transthoracic echocardiography (TTE). TTE demonstrated an abnormal giant mass dorsad to the right atrium and right ventricle. Although color Doppler TTE revealed abnormal blood flow within the left atrium (LA), the mass was not well visualized. Coronary angiography revealed a normal left coronary artery and an 80-mm internal diameter (ID) aneurysm at the proximal portion of right coronary artery (RCA). The giant aneurysm did not allow the distal part of RCA to be visualized. Meanwhile, threedimensional computed tomography (3-D CT) revealed three giant coronary artery aneurysms (CAAs) (Fig. 1). To avoid the risk of aneurysm rupture, surgery was planned.

Paraplegia caused by giant intradural herniation of a lumbar disk after combined spinal-epidural anesthesia in total hip arthroplasty

Total paraplegia after epidural or spinal anesthesia is extremely rare. We herein report a case of total paraplegia caused by a giant intradural herniation of a lumbar disk at the L3-L4 level after total hip arthroplasty for coxarthrosis. The patient had no preoperative neurologic abnormalities. Intraoperative anesthetic management involved combined spinal-epidural anesthesia at the L3-L4 level with continuous intravenous propofol administration. Postoperatively, the patient complained of numbness and total paraplegia of the lower extremities. Magnetic resonance imaging showed a giant herniation of a lumbar disk compressing the spinal cord at the L3-L4 level. The intradural herniation was surgically treated, and the patients symptoms completely resolved.