Improving safety: Neuraxial blockade guided by thromboelastography for patients with uncertain coagulation profile

ABSTRACT

Neuraxial blockade procedures are essential for anesthesia and pain management but pose risks in patients with uncertain coagulation profiles. Traditional coagulation tests often fail to predict bleeding risks associated with neuraxial blockade. Thromboelastography (TEG) offers real-time insights into coagulation status, potentially improving safety outcomes. In this case series, six patients underwent neuraxial blockade guided by TEG analysis. An individualized anesthetic plan was formulated based on TEG findings to mitigate bleeding risks while ensuring pain management. Tailoring anesthetic techniques to real-time TEG data improved safety outcomes with minimized bleeding complications and satisfactory pain control. In conclusion, neuraxial blockade guided by TEG enhances safety in patients with uncertain coagulation profiles. Further studies are needed to validate benefits in broader clinical settings.

Introduction

Central neuraxial blockade techniques are conventionally preferred for surgeries below the umbilicus when there is a concern about the risk of aspiration, delayed recovery, prolonged mechanical ventilation, and anticipated difficult airway.[1] There exist clinical situations where anesthesiologists are in a dilemma about neuraxial anesthesia over general anesthesia due to an abnormal conventional coagulation profile. Bleeding diathesis including a deranged standard coagulation profile, that is, prothrombin time (PT)/international normalized ratio (INR) and low platelet count, has been conventionally labeled as an absolute contraindication for central neuraxial anesthesia due to the risk of developing hemorrhage leading to sensorimotor deficits.[2]

The current practice of performing neuraxial anesthesia is supported by the American society of regional anaesthesia and pain medicine (ASRA) guidelines.[2] Despite the guidelines, there are no formal recommendations on the cut-off values of standard coagulation parameters to perform the neuraxial blockade.

PT/INR measures the extrinsic and common pathways of the coagulation cascade. It specifically evaluates the functionality of factors I (fibrinogen), II (prothrombin), V, VII, and X.

aPTT measures the intrinsic and common pathways, assessing factors I, II, V, VIII, IX, X, XI, and XII. These tests are performed on plasma and are sensitive to specific factor deficiencies or inhibitors. The comprehensive point of care (POC) coagulation test TEG determines the dynamicity of blood clot formation (speed of clot formation, strength of the clot, and extent of clot lysis).[3] Thus, TEG, together with other coagulation studies, could serve as a POC guide for safe neuraxial anesthesia administration.

In this case series, we present six patients with abnormal laboratory coagulation profiles but normal TEG studies who underwent surgeries under neuraxial blockade. A written informed consent was obtained in each case for the publication of data.

Case 1

A 33-year-old primigravida with a gestational age of 33 weeks presented with acute febrile illness (AFI) associated with headache, chills, and abdominal pain. On evaluation, she was diagnosed with dengue NS1 positive. AFI was complicated by thrombocytopenia, deranged liver functions, coagulation parameters, and bilateral pleural effusion. Due to the continuous aggravation of symptoms (headache and dyspnea), the multidisciplinary team decided for lower segment caeserian section (LSCS).

On the day of surgery (day 2 after admission), she was febrile and tachypneic (RR-36/min, SpO₂ 95% in the nasal prongs @4 L/min). Laboratory details revealed thrombocytopenia [Table 1] and deranged Liver function tests (LFT) bilirubin-2.21, Aspartate transaminase (AST)-637, Alanine transaminase (ALT) 174). TEG before the surgery was normal [Table 1]. Considering normal TEG, the decision of LSCS under subarachnoid (SAB) was taken. The patient underwent LSCS under SAB uneventfully. There were no immediate or long-term (6-month follow-up) neurological complications.

Table 1.

Type of surgery, standard coagulation profile, TEG values before surgery, and important anesthetic considerations

Surgery	PT (INR)/APTT/platelet count	TEG values R (min), K (min), alpha angle (degree), MA (mm), CL30 (%)	Important anesthetic concerns
Emergency LSCS	9.5 (0.86)/26.4/70000	3.5, 1.0,7 4.9, 72.9 0	Dengue with thrombocytopenia, bilateral pleural effusion
Below knee amputation	13.8 (1.4)/37/576000	3.7, 0.8, 79.5, 84.0, 3.6	CAD, PVD, sepsis pulmonary edema, anticoagulation
Percutaneous femur nailing	17.7 (1.63)/28.5/88000	6.7, 2.9, 56, 45.2, 7.7	Child Pugh B with hepatic encephalopathy grade 1
LSCS	9.7 (0.92)/23.6/46000	4.5, 1.5, 67.1, 65, 10.8	Chronic ITP
LSCS	9.3 (0.89)/23.9/65000	6.3, 1.5, 70.5, 65.9, 6.5	PIH with thrombocytopenia
Infected femur implant removal	14.3 (1.38)/28.8/120000	8.2, 2.5, 56.3, 59.5, 0.0	Child-Pugh B, sepsis

TEG- Thromboelastography, PT- prothrombin time, aPTT- activated partial thromboplastin time, LSCS-lower segment caesarian section, CAD-coronary artery disease, PVD- peripheral vascular disease, PIH-pregnancy induced hypertension, ITP-immune thrombocytopenic purpura

Case 2

A 30-year-old man, with a known case of coronary artery disease (CAD) and peripheral vascular disease (PVD), presented to the hospital with dyspnea. He underwent an emergency Left anterior descending (LAD) coronary artery thrombolysis 1 year ago. He was taking clopidogrel 75 mg OD, ecosprin 75 mg OD, dytor plus 10 mg OD, metoprolol 25 mg OD, and ivabridine 2.5 mg BD. His echocardiography revealed hypokinetic LAD territory with an ejection fraction of 35%. He had developed left foot gangrene associated with fever and leukocytosis (26000/mm³). Respiratory system examination revealed bilateral fine inspiratory crepitation.

The clopidogrel was stopped 4 days before and clexane 0.6 mg OD was started. TEG was performed [Table 1] before surgery and it was a normal study. The patient was posted for amputation below the knees with SAB for surgical anesthesia with popliteal, sciatic, and saphenous nerve blocks for postoperative analgesia. No immediate and delayed neurological complication was observed.

Case 3

A 73-year-old man with a known case of type 2 diabetes mellitus, hypertension, hypothyroidism, chronic kidney disease, and chronic liver disease (Child-Pugh B) presented with left intertrochanteric fracture and grade I hepatic encephalopathy. On further evaluation, minimal bilateral pleural effusion was noted. He also had anemia (8.1 g%), ascites, hypoalbuminemia (2.8 g/dL), hypokalemia (3.1 mEq/L), coagulopathy [Table 1], and consolidation of the left lower lung. He was started on medical management with diuretics, lactulose, antibiotics, and vitamin K injection. After initial stabilization, left percutaneous nailing of the femur was planned. TEG was performed preoperatively [Table 1] to guide perioperative blood transfusions and decide the plan of anesthesia. Regional anesthesia (epidural or subarachnoid) was planned after multidisciplinary team discussion. Two units of packed red cells were administered to correct anemia. He underwent surgery under SAB. Postoperative analgesia was achieved by blocking the iliac suprainguinal fascia. No immediate and delayed sensorimotor neurological complications were observed.

Case 4

A 34-year-old primigravida, a known case of chronic immune thrombocytopenic purpura (ITP), was posted for elective LSCS. She was on chronic steroid therapy for ITP. On admission, her platelet count was 32000 per mictroliter of blood. The patient did not have any history of bleeding tendencies. Two units of apheresis platelets were reserved for surgery. TEG was performed preoperatively [Table 1], which demonstrated LY 30 (10.8%). Tranexamic acid (dose) was administered. After informed consent, LSCS was performed under SAB. The procedure was uneventful. The patient did not require intraoperative blood or blood product transfusion. No immediate or long-term complications were observed.

Case 5

A 31-year-old female G3 P2L1A0, a known case of type 2 diabetes mellitus and pregnancy-induced hypertension (PIH), was planned for elective LSCS. She was on metformin and a calcium channel blocker. Her cell blood count was normal, except for a low platelet count (65000/mm³). A preoperative TEG [Table 1] revealed normal TEG values. The LSCS was performed under SAB and she did not require any blood or blood product transfusion.

Case 6

A 55-year-old woman, with a known case of hypertension, diabetes mellitus, and chronic liver disease (Child-Pugh B) was admitted to the emergency department with an infected left femur implant. She was admitted with cough, fever, hypotension, and worsening hepatic encephalopathy (grade 1). Pulmonary examination showed tachypnea and basal coarse crepitation with an oxygen saturation of 92% with a high-flow nasal cannula (HFNC). The chest radiograph showed bilateral consolidation. The patient was scheduled for emergency surgery for implant removal after initial resuscitation with fluids and empirical antibiotics with normal TEG study [Table 1] under subarachnoid block. No new focal sensorimotor neurological deficit was present in the lower extremities.

Discussion

In this case series, we have explored the utility of TEG-guided neuraxial blockade as a safe alternative for patients with uncertain coagulation profiles. This discussion will delve into the significance of our results, implications for clinical practice, and a review of the existing literature to support our findings.

Neuraxial anesthesia has been considered the gold standard for LSCS.[4] Abnormal coagulation profiles in pregnant women are commonly observed in cases of pregnancy-induced hypertension (PIH) and liver disease. Anticoagulation agents are used for thromboembolic phenomena and other pre-existing medical conditions. The three cases described here for LSCS are performed under the subarachnoid block with a deranged laboratory coagulation value (described above); however, the TEG study was normal. TEG-guided spinal anesthesia has been described in obstetrics and our study also explored the application of TEG in pregnant women with abnormal coagulation profiles.[5,6,7] The dynamic/deteriorating changes in the coagulation status in the perioperative period can be monitored by sequential TEG to guide the management of indwelling epidural catheters.

Similarly, abnormal coagulation status is often encountered in patients with liver diseases, and the two described cases had chronic liver disease (Child-Pugh B) posted for orthopedic surgeries with abnormal coagulation parameters.[8] The risk of decompensation was assessed in these cases and a regional anesthesia was chosen based on normal TEG reports.

One patient with CAD and PVD was on an anticoagulation agent and was scheduled for emergency surgery. The nature of systemic coagulation status in an amalgam of recurrent arterial thrombosis with anticoagulation agents and ongoing infection in this patient was evaluated by TEG. The decision of neuraxial anesthesia was made after analyzing the TEG report and the patient’s willingness. This case series supports the case study by Karan et al. who demonstrated TEG-guided epidural catheter management in a patient on anticoagulation.[9]

We used TEG to assess the coagulation status of patients before neuraxial blockade. It provides a comprehensive analysis of the entire clotting process, offering real-time information on clot formation, its strength, and clot lysis. This dynamic assessment allows us to have a more nuanced understanding of the coagulation status of a patient compared to static tests.[10]

The case series demonstrated that TEG-guided neuraxial blockade can be performed safely in patients with abnormal coagulation profiles in a certain population. We did not observe a significant increase in bleeding complications or adverse events compared to patients undergoing general anesthesia. This suggests that TEG provides valuable information that enables anesthesiologists to make informed decisions regarding the safety of neuraxial blockade in such a population.

This TEG-based case series has several important implications for clinical practice. Firstly, TEG should be considered a valuable tool in the preoperative evaluation of patients undergoing neuraxial blockade, especially those with uncertain coagulation profiles. It provides real-time information, allows precise decision-making, and maximizes the benefits of neuraxial anesthesia while minimizing risks. A clear risk–benefit analysis should be measured after multidisciplinary discussion before proceeding with regional anesthesia/neuraxial blockade in this subgroup of patients.

Traditionally, coagulation tests may not fully capture the dynamic nature of a patient’s coagulation status, which can lead to hesitancy in performing neuraxial blocks, despite their potential advantages such as improved postoperative pain management, decreased opioid consumption, and postoperative pulmonary complications. TEG expands the arsenal of anesthesia options available to anesthesiologists, particularly in cases where neuraxial anesthesia may be preferred over general anesthesia.

Conclusion

In conclusion, our case series highlights the safety and efficacy of TEG-guided neuraxial blockade in patients with uncertain coagulation profiles. By leveraging the real-time information provided by TEG, anesthesiologists can make informed decisions about the suitability of neuraxial anesthesia, thus improving patient safety and optimizing results.

Further studies with larger sample sizes are warranted to validate these findings and establish TEG as a standard tool in the preoperative evaluation of patients undergoing neuraxial blockade. These studies can collectively support the notion that TEG can improve the safety of neuraxial blockade by providing a more comprehensive assessment of coagulation status.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.