Author: Bob Kronemyer
Increasing the duration of anesthesia from five hours to 12 hours for microvascular reconstruction of the head and neck significantly increases the risk for surgical complications and the need for postoperative transfusion, according to a study in JAMA Facial Plastic Surgery(2018;20:188-195).
“When surgeons are performing this type of surgery, they should diligently try to cut down on anesthesia duration and excessive blood loss,” said co-author Richard Chan Woo Park, MD, assistant professor of otolaryngology at Rutgers New Jersey Medical School, in Newark. “This will prevent increases in postoperative complications.”
The six surgical complications assessed were superficial surgical site infection (SSI); deep incisional SSI; organ or space SSI; wound disruption; flap failure; and transfusion with 24 hours. Among 15 medical complications evaluated were pneumonia, unplanned reintubation, pulmonary embolism, mechanical ventilation greater than for 48 hours and renal insufficiency.
The study found that both surgical and medical complications increased with longer anesthesia time, but only surgical complications were increased significantly. The need for blood transfusion also increased dramatically with anesthesia of longest duration.
“I think there are inherent risks the longer the patient is not awake and not breathing on his own, and being given medications and fluids,” Dr. Park said. “Also, having open wounds, despite operating in a somewhat clean environment, can increase the rate of complications by a contaminated operative field of the head, neck, mouth and throat.”
In addition, bleeding increases with longer surgeries, thus increasing the likelihood of transfusion and other complications.
“These procedures typically take anywhere from five to 12 hours,” Dr. Park said. “That variability can be challenging, both to the surgical team and the anesthesiologist, for planning the course of fluids and transfusions and all the medication. We wanted to determine if there was a difference in rates of complications, based purely on the anesthesia duration or the length of operation.”
Five Groups Based on Surgery Duration
For the study, the American College of Surgeons’ National Surgical Quality Improvement Program (NSQIP) database was used to collect data on 630 patients who underwent head and neck microvascular reconstruction between 2005 and 2013.
Patients were stratified into five groups, based on mean anesthesia duration: 358.1 minutes (n=126); 563.2 minutes (n=125); 648.9 minutes (n=128); 736.5 minutes (n=125); and 922.1 minutes (n=126).
Bivariate analysis showed that the rate of 30-day overall complications was 43.7% in the group with the shortest exposure time to anesthesia and 63.5% in the group with the longest exposure time.
Similarly, the rate of 30-day overall postoperative surgical complications was 35.7% and 61.9%, respectively. Postoperative transfusion occurred in 25.4% of patients with the shortest anesthesia duration and 55.6% of patients with the longest. In addition, there were no wound disruption cases in the former group versus 7.9% in the latter.
“To be quite honest, none of the study results truly surprise me,” Dr. Park said. “Surgeons are all variable. For example, some surgeons are more methodical and may take slightly longer to perform these kinds of complex operations. Each hospital is also different, including the supporting staff, operating room conditions, supplies and anesthesiologists. Trying to streamline these variables and providing good care in the operating room are things we should all strive for, with the goal being effective efficiency.”
To reduce the likelihood of complications, Dr. Park said the anesthesia team should be in constant communication with the surgical team and vice versa. “The anesthesia team should also get a general sense from the surgeon as to how long the surgery can take. Certain cases of free-flap surgeries can take as little as four or five hours, while others take up to 10 to 12 hours. If the anesthesia team knows an approximate time up front, perhaps they will not be as aggressive in administering certain medications or fluids or transfusions.”
Because of the nature of the large database study as opposed to an institutional study, “there are limitations,” Dr. Park said. “We do not have specific patient medical records.”
Consequently, Dr. Park encouraged high-volume centers (200-300 flaps annually) to investigate for themselves the effects of anesthesia duration over a five-year study period, using more detailed and accurate patient records. “These centers will either be able to corroborate our study or discover outcomes that are different. I may conduct a similar institutional study at my own institution.”