Complications

Accidental Intra-arterial Injection

Severe digit or limb injury including amputation has occurred from accidental intra-arterial injection of medications as well as illicit drugs. Common sites include the brachial artery at the elbow or dorsum of the hand in the radial artery, as well as inadvertent injection into arterial lines in-situ.

The most severe limb injury has occurred after Pentothal, Diazepam, Penicillin, and Clindamycin. The most commonly injected illicit medications were crushed benzodiazepines (most commonly flunitrazepam). The potential for damage depends on the drug injected, and also its formulation – benzyl alcohol appears more harmful; commonly used agents like Propofol, Succinylcholine, Rocuronium, Fentanyl, amd Ketamine have not resulted in severe injury generally, although Propofol may cause severe pain.

Incidence is difficult to determine and has been estimated between 1:3,440 and 1:56,000 with old data. Mechanisms of injury can variously or in combination include direct endothelial injury, vasospasm, drug crystallization, and thrombosis.

Many empirical treatments have been reported with a less than strong evidence base, including steroids, vasodilators and nerve blocks. The most common regimes now recommended usually include anticoagulation with Heparin, Prostacyclin, and intra-arterial thrombolytics like TPA.

link

Transfusion-Associated Circulatory Overload in ICUs

Transfusion-associated circulatory overload is frequent in ICU patients, about 5.5% in this review. It was associated with increased ICU and hospital length of stay.

Risk factors included positive fluid balance, the number and type of products transfused, rate of transfusion, and cardiovascular and renal comorbidities. 

In pediatric ICUs, the authors note “The lack of a pediatric-adjusted definition of transfusion-associated circulatory overload may lead to a risk of underdiagnosis of this condition in PICUs”.

link

Intra-Abdominal Hypertension in Critically Ill Patients

In a mixed ICU patient cohort, intra-abdominal hypertension (IAH) occurred in almost half of all patients and was twice as prevalent in mechanically ventilated patients. Its presence and severity significantly and independently increased 28- and 90-day mortality.

Body mass index, APACHE II score of 18 or greater, presence of abdominal distension, absence of bowel sounds, and positive end-expiratory pressure greater than or equal to 7 cm H2O were independently associated with its development.

Positive fluid balance (as often occurs after massive resuscitation) appeared more relevant later in ICU stay. BMI was the only identified risk factor that was not directly related to increased mortality and different cutoffs for IAH may apply in obese patients.

IAH was defined as a value > 12 mmHg. The authors note: “presence and severity of IAH during the first 2 weeks of the ICU stay significantly and independently increased 28- and 90-day mortality, whereas the presence of IAH on the day of ICU admission was insufficient to predict these adverse outcomes”.

link

In addition to the above full text link, the Abdominal Compartment Society has useful links at its site as well as guidelines for managing IAH and abdominal compartment syndrome.

Cesarean Maternal & Neonatal Mortality in Africa

Maternal mortality after cesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average.

These shocking figures from a prospective observational study across Africa may be due to such factors as poor access to caesarean delivery, peripartum hemorrhage, and provision of anesthesia by non-physicians.

Suggested areas to improve include risk identification (eg, ASA status, risk of bleeding), care bundles and checklists and a higher level of monitoring, use of antifibrinolytic drugs (tranexamic acid), improved access to blood and blood products with long shelf lives, such as freeze-dried plasma and fibrinogen; and novel methods of training of non-physician anaesthetists, including online support and mobile-based applications.

Intraoperative Goal-directed Balanced Crystalloid versus Colloid

Another piece for the perpetual puzzle as to the harms and/or benefits of colloids vs. crystalloids.

The potential serious kidney injury and mortality using Hydroxyethyl Starch reported in critical illness are not always replicated in the intraoperative setting.

In this study in abdominal surgery, the primary outcome was a composite of serious postoperative cardiac, pulmonary, infectious, gastrointestinal, renal, and coagulation complications. Creatinine at 6 months was assessed.

Lactated Ringers or Hydroxyethyl Starch were given in a goal directed manner using esophageal Doppler based on stroke volume and corrected aortic flow time.

“Doppler-guided intraoperative hydroxyethyl starch administration did not reduce composites of serious complications. Nor did hydroxyethyl starch reduce the duration of hospitalization, but there was also no indication of renal or other toxicity”.

No clear reason to use Hydroxyethyl Starch is apparent, in view of the greater cost.

link

Lidocaine and Neurologic Outcomes after Cardiac Surgery

50% of cardiac surgery patients leave hospital with cognitive dysfunction which tends to improve but may persist at 5 years in some. Based on previous suggestion that Lidocaine may ameliorate such issues due to postulated anti-inflammatory, blood flow, and cerebral metabolism mechanisms, this randomized study failed to find benefit with use of Lidocaine infusion during and for 48 hours after cardiac surgeries.

Conclusion: Intravenous lidocaine administered during and after cardiac surgery did not reduce postoperative cognitive decline at 6 weeks.

The authors note the complex issues involved in cognitive dysfunction that could not be expected to benefit from a single agents – preoperative cognitive impairment, genetic predisposition, cerebral microembolism or hypoperfusion during CPB, inflammatory responses, hemodilution, hyperglycemia, hyperthermia, unmasking of Alzheimer disease, and acceleration of amyloid deposition associated with inhalational anesthetics.

link

Perioperative Hypotension and Cardiovascular Events

Another study adds to the now established theme that perioperative hypotension increases cardiovascular events and does so independently of the degree of coronary artery disease.

Hypotension is defined in this study as systolic blood pressure < 90mm Hg for at least 10 mins. Other studies have also used mean arterial pressure < 65.

The nuances show the effects were additive if not multiplicative. There was insufficient evidence that perioperative hypotension may have less deleterious cardiovascular effects in patients with a lesser degree of coronary artery disease compared to greater coronary artery disease.

“These data support efforts for the prevention, monitoring, and treatment of perioperative hypotension regardless of the presence or absence of significant coronary artery disease”.

link

Intraoperative Controlled Hypotension and Acute Kidney Injury

This was a retrospective study (immediate caveat!) on total hip arthroplasty under neuraxial anesthesia with intraoperative controlled hypotension (MAP < 60).

Acute kidney injury occurred in 45 (1.85%) of the 2431 patients in this cohort. Longer duration of hypotension was not associated with increased odds of postoperative AKI. Preexisting differences, such as compromised renal function, best predicted increased odds of AKI.

link

The authors speculate that inadvertent and controlled hypotension may be different. Hypotension may have surgical benefits but this study should be interpreted with caution in view of the known evidence on the cardiac, renal and mortality associations ( link ).

Methylprednisolone for AKI in Cardiac Surgery

A sub study of a randomized trial finds: “Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery”.

link

A previous review casts doubt on the use of steroids for various purposes in cardiac surgery, finding that they had “an unclear impact on mortality, increased the risk of myocardial injury, and the impact on atrial fibrillation should be viewed with caution given that large trials showed no effect”. link

Dexamethasone in Surgical Patients

Dexamethasone use as an anti-emetic has become near universal in anesthesia practice. This systematic review sought to ascertain whether it causes adverse side-effects.

The primary outcomes were postoperative systemic or wound infection, delayed wound healing and glycemic response within 24 h.

No link to wound infections was found, while it was unclear whether it affected wound healing. Mild increases in glucose within 12 hours occurred (mean difference 0.7mmol/L).

link