and nutritional effects
Neuroendocrine
Systemic inflammatory response
Pain
Impact of host factors and comorbid conditions
“Surgical complications,” otherwise referred to as “operative complications,” are not restricted to the time window of the surgical procedure itself but comprise both intra‐ and postoperative complications [2]. The duration of surgery defines the time window for intraoperative complications; meanwhile, postoperative complications are not restricted to those occurring during hospitalization but are defined according to a time period. A 30‐day period after the surgical procedure, either during or after hospitalization, has been used in human medicine [2].
All surgical procedures are associated with a degree of risk and the benefits of any procedure need to be weighed against any potential complications so that the clinician and the patient or animal owner can make a balanced and informed decision. This discussion should also cover complementary techniques that augment results to optimize physical, occupational and societal goals [3]. In veterinary medicine, owners’ expectations, engagement and commitment, animal welfare and economics need also to be balanced.
Surgical complications can be classified into patient‐related complications (related to patient‐specific characteristics, rather than to a procedural error), and practitioner‐related complications (arising from errors that directly lead to undesirable and unintended results affecting the patient, but also as a result of a faulty technique) [3]. Although surgical errors may be frequently linked to complications, some errors may not result in complications.
Recognition of errors and complications provide unique instances to learn from and to work toward avoiding or preventing their re‐occurrence [4]. To maximize this process the following practitioner's goals have been defined in human medicine [3, 5]:
1 Minimize errors by applying an appropriate surgical technique.
2 Identify and manage errors in a timely manner and in a way that would prevent ensuing complications.
3 Identify and manage complications in a timely manner and appropriately.
4 Identify and consider patient‐related complications in the decision‐making process, so that they can be anticipated, prevented or managed correctly.
It is not uncommon for clinicians to adopt routines that prevent and manage complications on the basis of personal experience. However, in some cases this may be associated with “making the same mistakes with increasing confidence over an impressive number of years” [6]. In human medicine, standards of expected outcomes for groups of patients require evidence‐based practice, making seniority and individual experience less important [7]. Evidence‐based literature in this area has quickly developed over the last decades, and several textbooks and journals dedicated to surgical complications are available in the human field. The application of an evidence‐based approach for prevention, identification and management of surgical complications should result in a reduction in mistakes in the clinical decision‐making process. In addition, it will also identify areas on which further research is warranted.
Morbidity and Mortality
Morbidity (from Latin morbidus, meaning sick, unhealthy) is a diseased state, disability, or poor health due to any cause [8]. Surgical morbidity relates to those morbid states that are related to a surgical procedure performed on a patient. Although traditionally defined by the presence or absence of specific postoperative complications, surgical morbidity represents any clinically significant, non‐fatal, adverse outcome associated with a surgical procedure [9]. Morbidity can be divided into local (associated with operation site, e.g. wound dehiscence) or general (related to any operation, e.g. acute renal failure). It can also be subdivided based on timely occurrence as intraoperative or postoperative; the latter being further considered as immediate, early, late or long‐term, although these are based on arbitrary time thresholds [9]. These categories overlap and are closely interconnected, as for example a specific, local complication such as surgical site infection may have general or systemic effects such as pyrexia, inappetence and motor dysfunction, which are not procedure specific [9].
Surgical mortality is any death regardless of cause, occurring: (1) within 30 days after surgery in or out of the hospital; or (2) after 30 days during the same hospitalization period subsequent to the operation [10, 11]. In patients undergoing more than one surgical procedure during a single hospitalization, mortality is assigned to the first operation during hospitalization [10].
In human medicine, postoperative morbidity has been shown to have a significant effect on mortality in patients undergoing major surgery; [12] however, the association between general postoperative morbidity and long‐term outcome or functionality is not well established [9]. This stems from the inconsistent reporting of morbidity in relation to definition, type and criteria, which leads to a lack of reliability in the recording of complications data [9]. Surgical mortality is a concrete universal outcome measure, but unlike morbidity, mortality recording has traditionally been inconsistent as a result of variable duration of hospitalization, follow‐up information, and number of surgical procedures performed during the same hospitalization period or different hospitalization periods [10].
Evidence‐based knowledge on complications has rapidly evolved and continues to do so in human medicine. The Morbidity and Mortality Conferences (MMCs) were established in the beginning of the 20th century at the Massachusetts General Hospital in Boston [13], with the aim to improve the quality and safety of human healthcare [14]. The MMCs have become a requirement for all human medicine surgical training programs in high‐risk specialties such as surgery, anesthesia, intensive care and oncology, being a key factor in the accreditation of human hospitals [15]. These conferences are associated with improvements in healthcare quality and patient safety through analysis of failures [15]. To further improve the effectiveness of these MMCs, additional structured frameworks such as the Physician Peer Review have been implemented, enabling surgeons to review and evaluate peer surgeons’ results and take corrective actions [16, 17]. These systems aim to improve competencies, protect patients from harm and assist institutions in their evaluations of surgical outcomes, with the ultimate goal of improvement of patient outcome through implementation of measures to identify and prevent operative complications.
In 1991, Copeland et al. developed the “Physiological and Operative Severity Score for the numeration of Mortality and morbidity (POSSUM)” as a representative method for evaluating the result of surgery in patients [18]. This system includes a physiological score and an operation severity score to calculate individual risk for morbidity and mortality. Classification systems for perioperative complications (such as the Clavien–Dindo classification) have been developed [19] and application of these systems has confirmed their prediction of morbidity and mortality rates in humans [20]. Over the last few years, equine studies have focused on identification of prognostic factors, mainly associated with mortality, in patients suffering from certain conditions or undergoing specific surgical procedures. From those studies, risks factors have been identified which provide useful information during the decision‐making process between veterinarian and horse owner. However, inconsistent definitions, limited populations and diverse management regimes often limit universal conclusions. Adaptations of POSSUM‐like strategies to the equine surgical field warrant consideration.
Surgical Checklists
The Safety Checklist was developed by Dr. Atul Gawande with the intention of improving outcomes, team dynamics and patient safety in an intensive care unit of a human hospital [21].
