This study demonstrates an incidence of 8.9% of KD in a group of patients that had undergone major orthopaedic procedures in our hospital over a period of one year. Also an assessment of numerous of potential risk factors of postoperative KD was carried out.
Definition of acute renal failure is still controversial and sometimes confusing [19
]. Authors have used terms such as renal insufficiency, renal dysfunction, acute renal failure (ARF), and renal failure requiring dialysis somewhat interchangeably [20
]. The lack of consensus in the quantitative definition of ARF, in particular, has hindered clinical research since it confounds comparisons between studies. Some definitions employed in clinical studies have been extremely complex with graded increments in serum creatinine for different baseline serum creatinine values [7
]. However, the Acute Dialysis Quality Initiative (ADQI) recognizing the need for a uniform definition for ARF, proposed a consensus graded definition, called the RIFLE criteria [22
]. The ESRD is a term that only indicates chronic treatment by Kidney Injury Network, which included the ADQI group as well as representatives from other nephrology and intensive care societies. In addition, the term acute kidney injury (AKI) was proposed to represent the entire spectrum of acute renal failure [23
Chronic kidney disease (CKD) as defined in 2002 by the Kidney Disease Outcomes Quality Initiative (K/DOQI) of the National Kidney Foundation is either kidney damage or decreased kidney function for 3 or more months [24
]. Numerous reports in the literature attempt to assess various factors those contribute to postoperative outcome of kidney function. These factors can be described as the preoperative comorbid status, the type of surgical procedure, and the postoperative period [25
It is known that the overall incidence of KD after elective or emergency orthopedic surgical procedure is up to 9.1% [1
]. Moreover, it has been reported that pre-operative renal dysfunction is a risk factor for postoperative complications, including AKI and cardiovascular disease [15
], leading to prolonged morbidity or hospital stay [28
] and to increased mortality [16
]. In addition, electrolyte and fluid balance have been implicated as important factors that can influence morbidity and complications [29
]. We did not found a significant difference in mortality in patients with sustained AKI compared with patients with transient AKI. A possible explanation could be the small number of deaths so our findings should be regarded with caution.
It is generally recognized that risk factors for the development of KD in this population include dehydration, increasing age, diabetes mellitus, shock, heart failure, medications (NSAIDs, aminoglycosides, ACE-I, diuretics, AT-II, opiates), rhabdomyolysis, iodinated contrast agents and pre-existing KD. In a recent study by Bennet et al. [2
], authors found that the male sex, vascular disease, hypertension, diabetes, chronic kidney disease and pre-morbid use of nephrotoxic medications were the main risk factors of AKI in patients with a fractured neck of femur. The most important risk factor for postoperative KD in the present series was the dehydration at admission; the second most significant was the history of diabetes mellitus while as third significant risk factor the pre-existing KD was noted. These findings may be associated with the increased mean age of KD group of patients. There are studies that support our findings [2
]. A diminished physiological response to the trauma coupled with enforced fasting, anaesthetic agents and blood loss caused by the injury and surgery exacerbate this as an additional stress on an already frail patient. A recent analysis by White et al. [1
], has shown that approximately one-third of patients presenting for surgical fixation of fractured neck of femur have at least moderate renal dysfunction on admission to hospital, a prevalence that increases with age. The authors indicated that these patients had a higher perioperative risk of opioid-induced respiratory depression, necessitating consideration of opioid-reducing strategies such as early fracture fixation, regular simple analgesia and regional nerve blockade. On the contrary, our study was not able to estimate the opiates as a significant risk factor for KD, due to limited sample size. On the other hand we found that there is an 8.5% higher risk of KD with an increase of age by one year. Novis et al. [31
] reviewed the potential preoperative risk factors for postoperative KD and showed that cardiac risk factors appeared predictive of postoperative renal failure. In our study, heart failure was a potential risk factor for the development of postoperative KD, but it was not correlated with the recovery of kidney function at the preoperative level. In this series potential risk factors for the development of KD were pre-existing KD, dehydration, diabetes mellitus, shock, NSAIDs, aminoglycosides, ACE-I, AT-II, diuretics, heart failure, opiates, rhabdomyolysis and iodinated contrast agents.
Optimal fluid balance, as well vigilance and caution especially for patients with high risk of KD, are crucial. This statement is in agreement with other authors [1
]. White et al. [1
] suggest that preoperative kidney dysfunction should alert the anesthetists for the appropriate adjustment of peri-operative analgesic administration, and adequate intra-operative intravenous fluid management, in patients with ‘borderline’ renal function. Multitrauma cases or elderly with hip fractures frequently present dehydrated at admission. A diminished physiological response to the trauma coupled with enforced fasting, anaesthetic agents and blood loss caused by the injury and surgery exacerbate this [2
]. Absolute or relative hypovolaemia is a significant risk factor for ARD development [21
]. Numerous of studies have shown that post-operative outcome can be positively influenced by optimising volume status and oxygen delivery perioperatively using invasive monitoring [32
Measures to prevent preoperative KD include close evaluation of patients with risk factors and monitoring by a specialist. A consideration of opioid-reducing strategies such as early fracture fixation, regular simple analgesia (but not non-steroidal anti-inflammatory drugs) and regional nerve blockade is necessary. Also an appropriate volume of fluid was required to optimize cardiovascular status, reflecting that the current standard care renders patients under-resuscitated before, during and after surgery.