A QASM
January 2023 (Volume 3) Anticoagulation and the older surgical patient
Data from the Queensland Audit of Surgical Mortality (QASM) shows that a high percentage of patients (age 65 or older) had haemorrhages as a consequence of anticoagulation.
A QASM assessor stated: 'Chartingofanticoagulantmedicationaroundthetimeofsurgeryshouldbemeticulouslydetailedregardingtimingand dosage.Simplywriting"withholdperioperatively"onthemedicalchartandwriting"chemicalVTEprophylaxisfromtomorrow"withoutmaking changestothemedicationchartcreatesanenvironmentforerrors.'
This QASMperspective presents data for Queensland patients with recorded haemorrhage and anticoagulant treatment who died in hospital (QASM patients) or who were discharged from acute public and private hospitals (Queensland Hospital Admitted Patient Data Collection - QPHADC). Haemorrhage includes subarachnoid, intracerebral and non-traumatic intracranial haemorrhage, cerebral infarction and stroke. The dataset also included patients with cerebral haemorrhage occurring after a fall.
BACKGROUND
Anticoagulant use is increasing as the population ages and general practitioners (GPs) prescribe anticoagulant treatment more frequently to combat potential consequences of cardiac, intracranial or mesenteric thrombosis.1,2
Anticoagulant treatment for stroke prevention and coronary artery disease has improved but unexpected consequences can arise in several conditions, particularly in elderly patients.2 These include intracranial bleeds and mesenteric arterial disease with bowel ischaemia. Anticoagulant treatment may interact with other drugs as well as antimicrobial therapy.3-5 Side-effects of anticoagulant treatment interactions increase coagulopathy and create postoperative crises including haematomas and postoperative bleeds.3-5
Failure to review and recognise a patient’s anticoagulation status prior to surgery can result in postoperative haemorrhage.6 Drug-induced coagulopathy can also result in intracranial bleeds after a fall.7
QUEENSLAND PATIENTS (1 January 2017–31 December 2021)
The number of Queensland patients who were admitted overnight to acute public and private hospitals, and who had haemorrhage and anticoagulant treatment noted in their medical records, was accessed from QHAPDC.
The dataset comprised 1,797 patients with 3,256 episodes of care. Haemorrhage in the context of anticoagulant treatment occurred in approximately 0.06% of QHAPDC episodes of care (i.e. 1,797 of approximately 2,984,250 episodes of care during the period January 2017 to Dec 2021). In 73.0% of episodes of care (1,311/1,797) involving haemorrhage and anticoagulant treatment, the patient was age 65 or older.
QASM PATIENTS (1 January 2017–31 December 2021)
QASM reviewed 5,351 in-hospital deaths and determined that 14.7% of these patients had haemorrhage while taking anticoagulant treatment (786/5,351). Most patients with haemorrhage while taking anticoagulant treatment were admitted to the following specialties: General Surgery, Orthopaedics, Neurosurgery or Cardiothoracic Surgery, and were age 65 or older (73.9%; 581/786) (Table 1). For those age 65 or older, patients admitted to Orthopaedics, Vascular Surgery, Urology and Plastic/Reconstructive Surgery were more likely to experience haemorrhage as a consequence of anticoagulant treatment compared to General Surgery. For those age younger than 65, Cardiothoracic Surgery patients were more likely to experience haemorrhage as a consequence of anticoagulant treatment compared to General Surgery patients.
Table 1. Patients with haemorrhage while taking anticoagulant treatment by surgical specialty and age group
#Excludes any surgical specialties with 5 or less patients (i.e. oral/maxillofacial surgery and plastic and reconstructive surgery); numbers too low to calculate and patients would be identifiable.
*Statistically significant at 95% confidence interval (CI). The odds ratio is used to report the strength of association between an exposure (i.e. surgical specialty) and an outcome (i.e. haemorrhage while taking anticoagulant treatment). It is the ratio of the odds of the outcome happening in one surgical specialty versus the reference group (General Surgery). The larger the odds ratio, the stronger the association. The smaller the odds ratio, the less likely the event is to be found with exposure. If the 95% CI for the odds ratio includes 1, then the odds ratio did not reach statistical significance.
QASM CASE STUDY
A man aged in his late-80s had a fall at home, fracturing the right neck of femur. His medical history included a pacemaker, atrial fibrillation and early dementia. He was taking metoprolol, atorvastatin, warfarin, perindopril and frusemide.
Two days post-fall, his hip was pinned with a plate and dynamic hip screw. Lower limb bullous lesions were noted during admission. Histological diagnosis was bullous pemphigoid and the patient was started on oral doxycycline. Warfarin was withheld preoperatively and restarted five days postsurgery. No intraoperative or postoperative complications were reported. He was nursed and rehabilitated on the ward.
Eight days post-surgery, the patient had an increased international normalised ratio (INR). His clinical condition deteriorated the following day. He was drowsy and pale with low blood pressure. A medical emergency team call was made; an upper gastrointestinal (GI) bleed was diagnosed and treatment instituted. Resulting hypovolaemia caused the patient's death.
There are risks involved in treating anticoagulated patients in the perioperative setting.
LESSONS
Anticoagulants are recognised as highalert medications, that need strategies to reduce the risk of harm. Coadministration of warfarin and doxycycline contributed to this patient’s demise. Better assessment and management of anticoagulation status throughout the admission is critical. Understanding anticoagulant medicines, dosages and potential drug interactions must be addressed. Drug interactions should be checked throughout the admission whenever medications are commenced or ceased. A clinical pharmacy review may have mitigated the error.
DISCUSSION
There are several possible reasons for the deranged INR. Dietary changes or fasting combined with a physiologically stressed state may have been contributing factors. Doxycycline is known to interact with warfarin and can result in an enhanced anticoagulant effect.3,4 The interaction can increase plasma levels of free warfarin and cause severe bleeding. Administration of warfarin with coadministration of doxycycline requires daily monitoring of INR for the first three days and a downward adjustment of the warfarin dose if necessary.
RECOMMENDATIONS
• Review each patient’s anticoagulation status prior to surgery.
• Consider patients on anticoagulants (i.e. unfractionated heparin [either standard or low molecular weight heparin], warfarin, apixaban, rivaroxaban or dabigatran) as highrisk: they frequently represent subjects of hospital-associated adverse events.
• Encourage awareness of the Queensland Health Anticoagulantguidelinefor hospitalisedadultpatients(Feb2022).
• Document in-hospital prescribed warfarin in the designated medication ordering section of the electronic medical record or in the dedicated warfarin prescribing section on the NationalInpatientMedicationChart (NIMC) of paper-based medical records.
• Encourage awareness of the NIMC, a standardised tool for communicating patient medication information consistently between health professionals.
• Ensure awareness of existing medications when prescribing additional drugs, and check for drug interactions in available resources and references and assess the risks vs benefits of the options.
• Ensure monitoring requirements are met (e.g. INR when reinstating warfarin post-surgery and when new medications are commenced).
• Improve GP understanding of prescribing and monitoring of anticoagulation therapy, particularly for patients older than 65 and those on antimicrobial therapy,5 and encourage adherence to Queensland Health guidelines for warfarin management in the community.
• Educate nurses and doctors annually on anticoagulant treatment guidelines at their hospital.
RESOURCES
Queensland Health. Anticoagulant guideline for hospitalised adult patients. February 2022. Available from: https://www.health.qld.gov. au/__data/assets/pdf_file/0015/1152213/ statewide-anticoagulant-guideline.pdf
Douketis JD, Lip GYH. Perioperative management of patients receiving anticoagulants. 2022. UpToDate, Inc. Available from: https://www.uptodate.com/contents/ perioperative-management-of-patientsreceiving-anticoagulants
Australian Commission on Safety and Quality in Health Care. Medication without harm – WHO global patient safety challenge: Australia’s response. 2020. Available from: https://www.safetyandquality.gov.au/ourwork/medication-safety/who-global-patientsafety-challenge-medication-without-harm Australian Commission on Safety and Quality in Health Care. National Inpatient Medication Chart (NIMC) – User Guide. 2019. Available from: https://www.safetyandquality.gov.au/ publications-and-resources/resource-library/ national-inpatient-medication-chart-nimcuser-guide
Australian Medicines Handbook 2020 (online). Adelaide: Australian Medicines Handbook Pty Ltd; 2020 July. Available from: https:// amhonline.amh.net.au/
Queensland Health and the Royal Flying Doctor Service Queensland Section. Guidelines for warfarin management in the community. 2016). Available from: https:// www.health.qld.gov.au/__data/assets/pdf_ file/0025/443806/warfarin-guidelines.pdf
REFERENCES
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