Retrospective, multicenter analysis of the safety and effectiveness of direct oral anticoagulants for the treatment of venous thromboembolism in obesity

BACKGROUND

Direct oral anticoagulants (DOACs) are the preferred treatment for venous thromboembolism (VTE). However, DOAC use in patients with a BMI greater than 40 kg/m2 has not been well studied despite the growing prevalence of obesity, and current literature is often underpowered.

METHODS

This multicenter, retrospective, observational study evaluated patients 18 years and older who received DOACs for acute VTE treatment. Patients receiving DOACs for recurrent VTE or for failure of another agent were excluded. The primary efficacy outcome was recurrent VTE and the primary safety outcome was major bleeding within 12 months (or one month after stopping anticoagulation therapy). A propensity score analysis was performed to balance patient characteristics and evaluate the primary endpoints by BMI group. Time-to-event outcomes were analyzed using weighted Kaplan-Meier curves.

RESULTS

There were 165 patients with a BMI of at least 40 kg/m2 and 320 patients with a BMI less than 40 kg/m2. The majority received apixaban (373, 77%). Recurrent VTE occurred in 5 (3.0%) and 13 (4.1%) of patients in the higher and lower BMI groups, respectively (adjusted OR: 0.66; 95% CI: 0.16-2.69). Major bleeding occurred in 5 (3.0%) and 15 (4.7%) of patients in the higher and lower BMI groups, respectively (adjusted OR: 1.19; 95% CI: 0.36-3.92).

CONCLUSION

There was no significant difference in VTE recurrence or major bleeding related to BMI among patients treated with DOACs. This study showed that DOACs may be a safe and effective VTE treatment option in patients with obesity.

[Norman Bethune (1890-1939), an involved doctor, icon of the blood transfusion history]

Norman Bethune was born in 1890, in Gravenhurst (Ontario, Canada). Thereafter a strong surgical training, he implied in thoracic surgery and fight against tuberculosis. His political opinions led him to join the Republicans in the Spanish Civil War. He played an important part in the development of blood transfusion on the battlefield. Then he joined China with communist troops and therein developed surgical units and accelerated training for health personal. He died of septicemia in 1939.

Successful but prolonged resuscitation after local anesthetic-induced cardiac arrest: is clonidine effective?

Local anesthetics when injected intravascularly result in serious cardiac complications including therapy-resistant cardiac arrest. We report a case of cardiac arrest after lumbar plexus block using a combination of 0.5% bupivacaine and 2% lidocaine with epinephrine (1:200.000). Resuscitation was performed by a combination of chest compression, repeated external countershocks and i.v.epinephrine. Clonidine had poor effect. The whole resuscitation required 90 minutes. The patient was discharged four days later without any sequelae. Blood sampling at 10 minutes showed a concentration of 2.02 mg/l lidocaine and 0.87 mg/l bupivacaine. Prolonged resuscitation is necessary in local anesthetic-induced cardiac arrest.

Contralateral effect of amitriptyline and bupivacaine for sciatic nerve block in an animal model of inflammation

BACKGROUND

Using a carrageenan inflammation rat model, we evaluated two experimental approaches to prolong sciatic nerve block on contralateral hyperalgesia. Method. We performed ipsilateral sciatic nerve block on the inflamed hind paw with bupivacaine-loaded microspheres suspended in dexamethasone (bupivacaine 12.5 mg) and with amitriptyline (6.25 and 12.5 mg) as ultralong-acting local anaesthetics. Bupivacaine (1.25 mg) was used as long-acting local anaesthetic and saline was used as a control. The sixth group received amitriptyline 6.25 mg intraperitoneally (n=10 for each group).

RESULTS

The duration of ipsilateral nerve block was 2 h for bupivacaine, 7 h for amitriptyline 6.25 mg, 11 h for amitriptyline 12.5 mg and 21 h for bupivacaine-loaded microspheres in suspension with dexamethasone. Whereas contralateral hyperalgesia was not observed during block produced by bupivacaine-loaded microspheres, contralateral hyperalgesia was observed with sciatic nerve block using amitriptyline.

CONCLUSIONS

Because of the differential effect observed on the contralateral side, the mechanism underlying the prolongation of ipsilateral block with amitriptyline may not result only from a prolonged Na(+) channel blockade but might be explained by a local toxic effect or lack of systemic actions.

Clinical perception of phantom limb sensation in patients with brachial plexus block

BACKGROUND AND OBJECTIVE

Patients' perception of limb position during regional anaesthesia is frequently incorrect. The incidence and nature of this phenomenon has not yet been completely described. The aim of this prospective study was to assess phantom sensation in patients undergoing a brachial plexus block.

METHODS

Axillary block was performed in 81 patients with the aid of a peripheral nerve stimulator. Immediately after the block, patients were allocated randomly to two groups (Group 1, n = 40; Group 2, n = 41) to have the blocked limb placed either on their thorax or in abduction. Fifteen minutes later, when the block was complete, the position of the limb was changed, without the knowledge of the patient, to a new position of abduction and flexion of the forearm. Patients were questioned about the new limb position. Fifteen minutes later, the limb was then transiently shown to the patient and further placed 'blindly' to another position. Patients were once more questioned about this new position.

RESULTS

Correct perception was more frequently observed in both groups following the first interview. Thirty-two and 34 patients gave at least one erroneous response about their limb position when it was initially placed on the thorax or in abduction respectively. Transient visualization of the limb position did not improve the rate of correct response.

CONCLUSIONS

Patients' perception of the position of the limb after axillary block in the majority of instances was probably due to persisting sensory inputs from the shoulder joint, which is not involved in this block. This is in contrast to supraclavicular or interscalene blocks. A significant number of patients experienced phantom limb sensation. They reported an arm position in fact related to the position of their arm before the axillary block.

Infraclavicular block with lateral approach and nerve stimulation: extent of anesthesia and adverse effects

BACKGROUND AND OBJECTIVES

The infraclavicular approach to the brachial plexus is little used despite theoretical advantages of the technique. Using a vertical paracoracoid approach, we assessed the extent of the sensory block and the incidence of adverse effects.

METHODS

After obtaining informed consent, 100 patients undergoing surgical procedures distal to the elbow were evaluated. The block was performed using a peripheral nerve stimulator. The puncture site was located in the infraclavicular fossa; the direction of the insulated needle was perpendicular to the skin. Motor response was sought in the hand or wrist at < or = 0.6 mA. A total of 40 mL of 1.5% mepivacaine was administered as a single injection. The sensory block was evaluated every 5 minutes for 30 minutes before surgery in the cutaneous distribution of terminal branches of the brachial plexus.

RESULTS

When one considers the cutaneous distributions of the median, ulnar, radial, and musculocutaneous nerves, the success rate was 89% for surgery without need for additional peripheral nerve blocks or general anesthesia. In contrast, cutaneous areas innervated by the axillary and medial cutaneous nerves were rarely anesthetized. We were unable to demonstrate a correlation between the intensity of the stimulation and the success of the block. On the other hand, a correlation was found between tourniquet sensation and the absence of anesthesia of the medial cutaneous nerve of the arm. Local anesthetic toxicity, Horner's syndrome, and vascular puncture were respectively observed in 1%, 4%, and 5% of cases. The depth of the needle introduction was correlated with the body mass index (P <.001; r =.63).

CONCLUSION

Single injection infraclavicular block, using a vertical paracoracoid approach, appears suitable for surgery distal to the elbow. Selective anesthesia of the medial cutaneous nerve is useful in improving tolerance of the tourniquet.

Lack of peripheral analgesia mediated by intraplantar administration of neostigmine in carrageenan-injected rats

BACKGROUND AND OBJECTIVE

The aim of the study was to test the peripheral analgesic action of neostigmine. Intraplantar administration of neostigmine was studied in carrageenan-injected rats.

METHODS

After assessing baseline values (T0) for paw circumference and the paw withdrawal threshold on both hind paws, the right hind paw was injected with 0.2 mL of 1% carrageenan and the left hind paw with 0.2 mL of saline (0.9% NaCl). Two hours later (T1), both hindpaws were tested for inflammation (paw circumference) and for hyperalgesia (paw withdrawal threshold) and subsequently 20 microg of neostigmine was injected in the right hind paw. The paw withdrawal threshold was tested again 10 (T2), 20 (T3) and 60 min (T4) and paw circumference 60 min (T4) after neostigmine injection.

RESULTS

Carrageenan injection in the right hindpaw was associated with a decrease in the paw withdrawal threshold reflecting mechanical hyperalgesia (P < 0.001) and an increase in paw circumference reflecting oedema (P < 0.001) in the right hind paw when compared with the left side from T1 to T4. Neostigmine had no effect on paw circumference and the paw withdrawal threshold at measuring points T2, T3 and T4 when compared with T1 in the right hindpaw.

CONCLUSION

Our results support the lack of peripheral analgesic effect of neostigmine.

Successful epidural blood patch in a patient with headache for 6 months after lumbar root decompression

Prolonged headache following dural puncture is an uncommon problem that may occur after a spinal tap, often as a complication of epidural anaesthesia. This problem has also been described after long-term epidural or spinal anaesthesia, myelography or spinal surgery. A case of prolonged postdural puncture headache following lumbar nerve root decompression is described in a healthy young man. No other cause could be found either clinically or with the aid of scanning by computerized tomography or magnetic resonance imaging techniques at the spinal level involved. The symptoms were successfully treated with an epidural blood patch performed seven months following the original surgical operation.

The effect of a sciatic nerve block on the development of inflammation in carrageenan injected rats

Neurogenic inflammation may participate in postoperative inflammatory pain. We evaluated, in the rat, the influence of a short and prolonged sciatic nerve block on carrageenan-induced inflammation, the time course of which may be compared to postoperative inflammation. A catheter was placed on the right sciatic nerve and injected with 0.5% bupivacaine with epinephrine (0.2 mL): one injection in the Short Block Group, and four injections performed at 90-min intervals in the Prolonged Block Group. In all groups, the two hind paws were then injected with carrageenan. The development of inflammation was evaluated in both hind paws by measurement of paw circumference (PC) before, and 1, 2, 3, 4, 6, and 24 h after carrageenan injection. Temperature of both hind paws was evaluated at the same time points. The vocalization threshold to paw pressure test (VTPP) of both hind paws was evaluated at 6, 8, 10, 12, and 24 h after carrageenan injection. The left hind paw was used for the Control Group. A Sham Group had a catheter placed on the sciatic nerve and injected with normal saline. Inflammation developed in the Control Group with a maximum increase of PC (32%) and temperature (14%) 4 h after carrageenan injection and a maximal reduction of VTPP (44%) at 6 h, reflecting mechanical allodynia. A similar evolution was observed in the Sham Group. In the Short Block Group, the nerve block did not influence the PC, the paw temperature, or the VTPP when compared with the Control Group. In the Prolonged Block Group, when compared with the Control Group, the increased PC was reduced throughout the 24 h (P < 0.0001). The maximal increase in PC at 4 h was limited to 23%, as compared with the precarrageenan value. This effect on PC did not persist at 24 h. Paw temperature was increased (P = 0.07) throughout the study in the Prolonged Block Group, as compared with the Control Group. The VTPP reduction was still limited in the Prolonged Block Group at 24 h, as compared with the Control Group (P < 0.0001). We conclude that a prolonged sciatic nerve block limits carrageenan-induced increase in PC and, subsequently, mechanical allodynia at 24 h in rats.

IMPLICATIONS

Our study has shown that a prolonged (6 h) but not a short sciatic nerve block (90 min) can limit edema and related pain after carrageenan-induced inflammation in rat.

[Headache and low back pain after epidural anesthesia]

Headache and low back pain are common minor complications after epidural anaesthesia. Headache is due to cerebrospinal leakage through the site of accidental dural puncture. Epidural blood patch is considered as the better curative treatment. Acute or long term backache is often reported after epidural anaesthesia. Different mechanisms are suggested: needle trauma, myotoxicity of local anaesthetic and postural problem. Large prospective randomized studies are yet necessary to clarify the role of epidural anaesthesia, the duration of symptoms and the therapeutic.

[Temporary relief from pain in the phantom limb after spinal anesthesia using a combination of bupivacaine and clonidine]

Two cases are reported of patients with phantom limb pain after lower limb amputation and requiring surgery of their stump. The stumps were revised and the remaining femoral shaft shortened. Both had spinal anaesthesia for this procedure, with an association of bupivacaine and 150 micrograms of clonidine. In one patient, the phantom pain did not resume for one month, and in the other for three days. The return of pain was preceded by the sensation of a phantom limb. These cases suggest that alpha 2 adrenergic agonists could play a major part in the treatment of phantom limb pain.

[Iterative epidural anesthesia after accidental dural puncture. Analysis with epidurography]

The case is reported of a 63-year-old man who was to undergo a gastrectomy for stomach carcinoma. An epidural catheter for postoperative analgesia (epidural morphine) was inserted into the T10-11 space prior to induction of general anaesthesia. Unfortunately, cerebrospinal fluid (CSF) surged back through the Tuohy needle, which was immediately withdrawn. It was decided to make a further attempt at the L2-3 level. This was successful, and no CSF could be aspirated through the catheter. Four hours after recovery, and epidurography was carried out (12 ml of lopamiro R 300). This revealed passage of contrast, medium from the epidural space into the subarachnoid space, with opacification of the caudal cul-de-sac. Another epidurography, 24 hours later, showed the same picture. The analgesic technique was therefore altered to subcutaneous buprenorphine. Careful management of this situation, in order to prevent total spinal anaesthesia, is discussed in the light of the literature.

[Accidental epidural injection of hypertonic sodium chloride solution]

Twenty ml of 20% hypertonic saline were accidentally injected into the epidural space of a 53-year-old man with lumbar backache and sciatica. This resulted in severe thoracolumbar pain, which disappeared after he received by the same route 20 ml of 1% lidocaine and 40 ml distilled water. Three months later, the sciatica had almost all disappeared; there remained no motor deficit. A literature survey helped to explain the signs described. Further cases of accidental epidural injections of other drugs are discussed.