Blood Salvage During Surgery

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Blood or cell salvage, also referred to as autologous blood transfusion or intraoperative blood salvage, is a medical procedure that consists in the harvesting red cells shed during surgery, processing and preparing them for safe return to the patient’s own circulation as an autologous red cell transfusion during or immediately after surgery 1. The first publication of cell salvage in humans appeared in 1818, but it was then still associated with a high mortality rate. It was not until the 1960s that intraoperative blood salvage in its current recognisable form was first introduced and has become increasingly critical as a strategy for blood management during and after surgery. This technique, born out of the necessity to reduce reliance on donor blood and its associated risks, is now important to enhancing patient outcomes, minimizing transfusion-related complications, and optimizing resource utilization during surgical interventions.


Blood salvage involves the collection, filtration, and reinfusion of a patient’s own blood that is shed during surgery. This process begins with the meticulous collection of blood from the surgical field using a specialized device known as a cell saver. The collected blood is then processed through a series of filters to remove debris, contaminants, and unwanted substances, leaving behind a purified autologous blood product ready for reinfusion. The salvaged blood may remain outside the body during much of the surgery and be re-infused near the end of the surgical procedure. Hospitals with formal bloodless medicine programs have a significant amount of experience with these techniques 2.


There are no good data to define the estimated blood loss at which blood salvage is appropriate. An estimated blood loss of approximately 1000 mL should justify a blood salvage procedure. However, it may be reasonable for some patients with estimated blood loss volumes ranging from 500 to 750 mL as well. However, different thresholds may apply to different patients, as the exact threshold is highly individual 3.


The versatility of blood salvage extends across a wide array of surgical specialties. This technique is implemented in the context various elective and emergency major surgical procedures, including cardiac, major vascular, major orthopedic, transplantation, trauma, and certain urologic, neurosurgical, gynecologic, and plastic surgical procedures 3. In cardiac surgery in particular, the ability to salvage and reinfuse the patient’s own blood aids in maintaining hemodynamic stability 4.


One of the primary advantages of blood salvage is its ability to minimize the risks linked to allogeneic blood transfusions. Allogeneic transfusions, while frequently necessary, carry risks such as infections, transfusion reactions, and immunological responses. By using a patient’s own blood, blood salvage significantly mitigates these risks, enabling a safer and more personalized approach to patient care 2.


As the demand for donor blood decreases, so does the financial burden linked to the processes of blood procurement, testing, and storage. By recycling and reinfusing a patient’s own blood, the need for external blood donors is reduced, thereby minimizing the demand for donor blood products. Blood salvage thus allows for resource optimization and cost-effectiveness in surgery with benefits for patients and healthcare institutions. However, additional research and long-term data on the cost savings of blood salvage during surgery is warranted 5.


While blood salvage has revolutionized surgical practices, challenges remain. Not all surgical scenarios are conducive to effective blood salvage, and careful patient selection and surgeon expertise are critical. Ongoing research is focused on addressing these limitations and exploring innovations, such as improvements in cell saver technology and the development of novel blood substitutes.




  1. Carroll, C. & Young, F. Intraoperative cell salvage. BJA Education (2021). doi:10.1016/j.bjae.2020.11.007
  2. Intraoperative Blood Salvage | Allegheny Health Network. Available at: (Accessed: 30th January 2024)
  3. Surgical blood conservation: Intraoperative blood salvage – UpToDate. Available at: (Accessed: 30th January 2024)
  4. Klein, A. et al. A survey of patient blood management for patients undergoing cardiac surgery in nine European countries. J. Clin. Anesth. (2021). doi:10.1016/j.jclinane.2021.110311
  5. McLoughlin, C. et al. Cost-effectiveness of cell salvage and donor blood transfusion during caesarean section: Results from a randomised controlled trial. BMJ Open (2019). doi:10.1136/bmjopen-2018-022352
harm reduction

How Harm Reduction Applies to Anesthesia

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Anesthesia is a critical aspect of medical practice and is especially important in ensuring patient comfort and safety during surgical procedures. However, it comes with inherent risks. In recent use, the concept of harm reduction, which was originally developed within substance use and public health, has become relevant and important in the field of anesthesia and healthcare in general (Hawk et al., 2017). In this article, we will discuss how harm reduction principles can be applied in the context of anesthesia.

As a concept, harm reduction focuses on minimizing the negative consequences of certain activities without necessarily eliminating the activity itself (Hawk et al., 2017). For example, a harm reduction program in substance use may focus on reducing overdose without directly reducing substance use. In the context of anesthesia, harm reduction includes identifying potential risks and mitigating them to enhance patient safety and optimize healthcare outcomes (Ladak, et al., 2021).

A key aspect of harm reduction in anesthesia includes conducting thorough patient-specific risk assessments. Individuals care plans are vital and must include patient history, comorbidities and medication regimens when creating treatment approaches (Ladak, et al., 2021). With this approach, anesthesiologists can tailor their interventions to the specific needs of each patient, therefore reducing the risk of adverse events.

The choice of anesthetic agents and their dosages significantly influences patient outcomes. For example, benzodiazepines were previously used often in anesthesia but are associated with many adverse effects including cognitive and psychomotor impairment. At higher doses, benzodiazepines can lead to paradoxical excitement in the elderly as older patients are more sensitive to benzodiazepines (Lader, 2014). The current prevailing viewpoint is to avoid them when possible in patients with a risk of experiencing adverse effects.

A case report on harm reduction for a surgical patient consuming fentanyl recreationally also demonstrated that a cornerstone of harm reduction in anesthesia is effective communication. Discussing strategies for harm reduction among clinicians and the patient led to an unconventional, personalized pain management approach that nonetheless reduced risk from self-administered illicit opioids. It is vital to establish clear lines of communication among all members of the healthcare team and that information is relayed promptly and in a streamlined manner (Ladak, et al., 2021).

Harm reduction in anesthesia extends beyond the operating room to postoperative care. Postoperative monitoring and follow-up is essential to identifying complications of surgery and or anesthesia and addressing them in a timely manner. This approach aligns with harm reduction principles by addressing potential risks during the perioperative period, minimizing the impact of adverse events on patient outcomes (Ladak, et al., 2021).

One large area of discussion in this arena is opioid analgesia. Opioids are used to treat many conditions that cause pain, but these medications carry a significant risk of adverse health effects. Harm reduction strategies to address opioid misuse have been studied in the emergency department, hospital floor, and intensive care units. Some examples of strategies include medication review on admission and discharge, presence of a pharmacist during rounds, education for the healthcare team on appropriate opioid dosing and use, and education on drug withdrawal symptoms (Deschamps et al., 2018). Notably, the American Society of Anesthesiologists was involved in the approval of naloxone hydrochloride nasal spray for over-the-counter, non-prescription use (“FDA Approves OTC Naloxone Consistent with Longstanding Asa Recommendations”, 2023).

In conclusion, harm reduction principles can be successfully applied to anesthesia practice and contribute to improved patient safety and outcomes. Through patient specific risk assessments, optimized drug selection, enhanced monitoring technologies, effective communication, and comprehensive postoperative care, anesthesiologists can mitigate potential risks associated with anesthesia administration. As the medical and scientific community continues to evolve, integrating harm reduction strategies into anesthesia protocols represents a potential and exciting approach to enhancing the quality of care provided to patients.



Deschamps, Jean et al. “Association between harm reduction strategies and healthcare utilization in patients on long-term prescribed opioid therapy presenting to acute healthcare settings: a protocol for a systematic review and meta-analysis.” Systematic reviews vol. 8,1 88. 5 Apr. 2019, doi:10.1186/s13643-019-0997-5

“FDA Approves OTC Naloxone Consistent with Longstanding Asa Recommendations.” American Society of Anesthesiologists (ASA), 29 Mar. 2023,

Hawk, Mary et al. “Harm reduction principles for healthcare settings.” Harm reduction journal vol. 14,1 70. 24 Oct. 2017, doi:10.1186/s12954-017-0196-4

Ladak, Salima S., et al. “The intersection of harm reduction and postoperative care for an illicit fentanyl consumer after major surgery: A case report.” Canadian Journal of Pain, vol. 5, no. 1, 2021, pp. 166–171, doi:10.1080/24740527.2021.1952066.

Lader, Malcolm. “Benzodiazepine harm: how can it be reduced?.” British journal of clinical pharmacology vol. 77,2 (2014): 295-301. doi:10.1111/j.1365-2125.2012.04418.x

Discharge Time After Surgery

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After surgery, the process of recovery is a continuous process that begins as the patient emerges from anesthesia and concludes when they have regained their preoperative physiological and functional state. Early recovery stages involve the period during which patients emerge from anesthesia, regain control of protective reflexes, and resume initial motor activity. Subsequently, in the second stage of recovery, patients ambulate, consume fluids, void, and prepare for discharge. Ultimately, patients are discharged to continue recovery at home until they resume normal activities of daily living. The duration of recovery varies, influenced by factors such as the surgery type, complications during the procedure, patient comorbidities, postoperative complications, and safe-discharge planning, and as a result, discharge time can range from hours to days or even weeks after surgery. 

Ambulatory surgery is defined as any operative procedure not requiring an overnight hospital stay. In contrast, inpatient surgery is where patients stay overnight or for multiple nights following the procedure. The trend towards shorter hospital stays has grown, and enhanced recovery after surgery pathways have become standard practice for most surgical procedures in many facilities. Outpatient surgical procedures have evolved significantly, with increasingly complex surgeries, including hip, knee, and shoulder arthroplasty, transitioning from traditional in-hospital care to short-stay or day-case procedures. Overall, many procedures are seeing decreased time to discharge after surgery. 

It is the responsibility of the physician to ensure that a patient is sufficiently recovered to leave the hospital or surgical center, under the appropriate care of a relative or caregiver. Premature discharge can cause harm due to residual psychomotor impairment and may result in legal consequences. Therefore, patients remain hospitalized until they meet specific discharge criteria, often assessed using established frameworks such as the post-anesthesia discharge score (PADS) developed by Chung and colleagues. PADS is a cumulative index evaluating vital signs, ambulation, pain, postoperative nausea and vomiting, and surgical bleeding. 

As surgical techniques and enhanced recovery pathways advance, more complex surgeries are now being performed as same-day surgery as the time to discharge after has dropped enough. Total hip arthroplasty and total knee arthroplasty, traditionally associated with inpatient stays, are now often performed on an outpatient basis due to innovations like minimally invasive approaches, tranexamic acid use, and multimodal and pre-emptive analgesia. Selection criteria for same-day surgery include individuals under 80 years without preoperative bleeding disorders, cirrhosis, clinically significant cardiac disease, or end-stage renal disease. Recent studies, such as one by Bodrogi et al., indicate that appropriately selected patients experience similar adverse event rates and functional outcomes as inpatient-protocol arthroplasty, with high patient satisfaction and cost-effectiveness. 

In conclusion, recovery is an ongoing process initiated post-surgery and persists until patients return to their physiological baseline. Discharge time after the procedure varies based on surgery type and recovery duration, ranging from same-day discharge to longer hospital stays. With continuous improvements in surgical techniques, an increasing number of surgeries will become feasible as same-day procedures, emphasizing the importance of careful patient selection and comprehensive perioperative care. 



  1. Bodrogi A, Dervin GF, Beaulé PE. Management of patients undergoing same-day discharge primary total hip and knee arthroplasty. CMAJ. 2020 Jan 13;192(2):E34-E39. doi: 10.1503/cmaj.190182. PMID: 31932338; PMCID: PMC6957327. 
  2. Pang G, Kwong M, Schlachta CM, Alkhamesi NA, Hawel JD, Elnahas AI. Safety of Same-day Discharge in High-risk Patients Undergoing Ambulatory General Surgery. J Surg Res. 2021 Jul;263:71-77. doi: 10.1016/j.jss.2021.01.024. Epub 2021 Feb 24. PMID: 33639372. 
  3. Lee L, McLemore E, Rashidi L. Same-Day Discharge After Minimally Invasive Colectomy. JAMA Surg. 2022;157(11):1059–1060. doi:10.1001/jamasurg.2022.4123. 
  4. Marshall SI, Chung F. Discharge Criteria and Complications After Ambulatory Surgery. Anesth Analg. 1999 Mar;88(3):508-517.  
  5. Jakobsson J. Recovery and discharge criteria after ambulatory anesthesia: can we improve them?. Curr Opin Anaesthesiol. 2019;32(6):698-702. doi: 10.1097/ACO.0000000000000784. 

Causes of Hemodynamic Instability during Surgery

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Each year, an estimated 230 million surgical operations are performed around the world. The influence of hemodynamic instability (or shock) during surgery on patient mortality and morbidity in is a very important clinical issue (1). There are four major categories of hemodynamic instability/shock: hypovolemic, distributive, cardiogenic, and obstructive. Hypovolemic shock is due to intravascular volume loss, distributive shock is caused by inadequate perfusion of the body’s vital organs, cardiogenic shock is secondary to decreased intrinsic cardiac function, and obstructive shock arises from a blockage of systemic blood circulation (2). Two surgical procedures that are associated with a greater chance of intraoperative hemodynamic instability are pheochromocytoma removal and carotid artery stenting. Although surgery techniques and anesthetic care have progressed considerably in recent years, hemodynamic instability (HI) is still a common complication of the aforementioned procedures, and can also happen in other clinical situations, though rare. Thus, identifying significant risk factors for hemodynamic instability in patients is important for safe and effective perioperative care by anesthesiologists and surgeons.

A pheochromocytoma is a rare neuroendocrine tumor that originates from chromaffin cells of the adrenal medulla, with an incidence of approximately 0.3-0.5 cases per 100,000 person-years. Often, pheochromocytomas synthesize and secrete excessive amounts of catecholamines (norepinephrine, epinephrine and dopamine), which can cause hypertension, tachycardia, palpitations, and various organ complications. The main treatment strategy for pheochromocytoma is surgery (adrenalectomy). However, manipulation of the adrenal gland can trigger acute life-threatening intraoperative catecholamine release and a subsequent hypertensive crisis. According to current guidelines, patients with pheochromocytoma should undergo preoperative medical treatment consisting of α- and β-adrenergic blockers to prevent perioperative cardiovascular complications (3). In 2018, Jiang et al. conducted a study to identify risk factors for hemodynamic instability during surgery for pheochromocytoma in patients at a single institution in China (3). In this study, it was found that tumor diameter > 50 mm was an independent risk factor for intraoperative HI. Previous studies have shown that larger tumors tend to secrete greater amounts of catecholamines, which would naturally lead to an increase of intraoperative HI. The study also showed that diabetes/hyperglycemia was also a significant predictor of HI. Autonomic neuropathy and HI are known complications of uncontrolled diabetes. This existing predisposition to HI is exacerbated by the catecholamine surge produced during pheochromocytoma removal (3).

Carotid artery stenting (CAS) is an alternative to carotid endarterectomy (CEA) to treat carotid artery disease, with proven safety and efficacy in multiple trials due to its less invasive nature compared to CEA. According to the current guidelines, CAS is preferred for patients with contraindications against CEA (i.e. age >80, severe cardiac disease, previous radical neck surgery or radiotherapy) (4). Hemodynamic instability is also considered a common complication in surgery patients after CAS. In a 2019 study, Rubio et. al found that lesions involving the carotid bifurcation and the presence of hypertension requiring 2 or more antihypertensive medications were independent risk factors for perioperative HI (4). Stimulation

of the carotid sinus baroreceptors by balloon dilation and stent deployment at or near the carotid bifurcation can lead to increased vagal tone and parasympathetic, consequently causing hypotension and/or bradycardia. On a related note, the association between the presence of severe hypertension and perioperative HI suggests that patients with more refractory hypertension requiring multiple medications may be at increased risk for reflex hypotension following CAS. Future studies are required to investigate whether withholding some or all antihypertensive medications in patients on multiple medications reduces the risk of perioperative HI (4).



1. Abebe MM, Arefayne NR, Temesgen MM, Admass BA. Incidence and predictive factors associated with hemodynamic instability among adult surgical patients in the post-anesthesia care unit, 2021: A prospective follow up study. Ann Med Surg (Lond). 2022;74:103321. Published 2022 Jan 29. doi:10.1016/j.amsu.2022.103321

2. Standl T, Annecke T, Cascorbi I, Heller AR, Sabashnikov A, Teske W. The Nomenclature, Definition and Distinction of Types of Shock. Dtsch Arztebl Int. 2018;115(45):757-768. doi:10.3238/arztebl.2018.0757

3. Jiang M, Ding H, Liang Y, et al. Preoperative risk factors for haemodynamic instability during pheochromocytoma surgery in Chinese patients. Clin Endocrinol (Oxf). 2018;88(3):498-505. doi:10.1111/cen.13544

4. Rubio G, Karwowski JK, DeAmorim H, Goldstein LJ, Bornak A. Predicting Factors Associated with Postoperative Hypotension following Carotid Artery Stenting. Ann Vasc Surg. 2019;54:193-199. doi:10.1016/j.avsg.2018.06.005

Risk Factors for Intraoperative Hypotension

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Intraoperative hypotension (IOH) is a common complication during surgical procedures under anesthesia [2]. IOH can lead to adverse outcomes, including organ dysfunction, increased morbidity, and longer hospital stays. Studies have shown IOH during noncardiac surgery is associated with an increased risk of 30-day major adverse cardiac or cerebrovascular events [1]. The definition of IOH has long been debated, but a recent systematic review found that when mean arterial pressure (MAP) falls under 80 mmHg for greater than 10 minutes, end-organ injury can occur [3]. Identifying and understanding the associated risk factors for IOH is crucial for preventing and managing intraoperative hypotension effectively.  

The choice of anesthetic agents and techniques can significantly influence the risk of intraoperative hypotension. Certain drugs, such as volatile anesthetics, induction agents, and opioids, can cause dose-dependent hypotension [4]. Additionally, regional anesthesia techniques, such as epidurals and spinal blocks, which cause a sympathetic blockade, can lead to IOH. Anesthesiologists should carefully select anesthetic agents and techniques, considering the patient’s overall health, surgical requirements, and risk factors for hypotension. Some of these risk factors include older aged patients who may be more susceptible to IOH due to decreased cardiovascular reserve and altered baroreceptor function. Furthermore, those with comorbidities like hypertension, diabetes, and cardiovascular diseases are at higher risk for IOH. Certain medications, such as beta-blockers, alpha-2 agonists, and angiotensin-converting enzyme inhibitors, can impact blood pressure regulation intraoperatively, and careful monitoring of patients on these agents is warranted [5].  

Intraoperative hypotension must be treated based upon the underlying etiology. Thus, determining the underlying cause of hypotension is essential in management [4]. One important step in management is assessment of volume status for hypovolemia, whether due to preoperative fasting, blood loss, or inadequate fluid replacement. The duration of surgery and type of surgery are also variables that can affect hemodynamics. Longer surgeries and those involving significant blood loss such as vascular or orthopedic surgeries are associated with a higher risk of intraoperative hypotension. Prolonged exposure to anesthetic agents and mechanical ventilation causing high intrathoracic pressure can also affect hemodynamics during surgery [5]. Additionally, the position a patient is in during surgery can affect venous return and cardiac output. The use of advanced monitoring techniques, such as arterial line and cardiac output monitoring, can help detect IOH early [5]. Continuous monitoring allows for prompt adjustments and interventions, fluid administration, or use of first-line vasopressors like ephedrine, phenylephrine, and norepinephrine [4].  

Overall, intraoperative hypotension is a common and potentially serious complication during surgery. Identifying and mitigating risk factors is crucial for ensuring patient safety and positive outcomes. An individualized approach that includes optimizing preoperative conditions, selecting appropriate anesthetic agents, and vigilant monitoring during surgery is essential in minimizing the risk of IOH and optimizing perioperative care.  



  1. Bijker JB, van Klei WA, Kappen TH, van Wolfswinkel L, Moons KG, Kalkman CJ. Incidence of intraoperative hypotension as a function of the chosen definition: literature definitions applied to a retrospective cohort using automated data collection. Anesthesiology. 2007;107:213–220 
  2. Gregory, Anne MD, MSc, FRCPC*; Stapelfeldt, Wolf H. MD‚Ć; Khanna, Ashish K. MD, FCCP, FCCM‚Ä°,¬ß; Smischney, Nathan J. MD, MSc‚Äñ; Boero, Isabel J. MD, MS; Chen, Qinyu MS; Stevens, Mitali PharmD, BCPS#; Shaw, Andrew D. MB, FRCPC*,**. Intraoperative Hypotension Is Associated With Adverse Clinical Outcomes After Noncardiac Surgery. Anesthesia & Analgesia 132(6):p 1654-1665, June 2021.  
  3. Wesselink EM, Kappen TH, Torn HM, Slooter AJC, van Klei WA. Intraoperative hypotension and the risk of postoperative adverse outcomes: a systematic review. Br J Anaesth. 2018;121:706–721. 
  4. Lonjaret L, Lairez O, Minville V, Geeraerts T. Optimal perioperative management of arterial blood pressure. Integr Blood Press Control. 2014 Sep 12;7:49-59. doi: 10.2147/IBPC.S45292. PMID: 25278775; PMCID: PMC4178624. 
  5. Kouz K, Hoppe P, Briesenick L, Saugel B. Intraoperative hypotension: Pathophysiology, clinical relevance, and therapeutic approaches. Indian J Anaesth. 2020 Feb;64(2):90-96. doi: 10.4103/ija.IJA_939_19. Epub 2020 Feb 4. PMID: 32139925; PMCID: PMC7017666