2018-19 Section 7-Neoplastic and Inflammatory Diseases of the Head and Neck eBook

Original Investigation Research

Anesthesia Duration and Head and Neck Microvascular Reconstruction Complications

Table 2. Operative Features Stratified by Anesthesia Cohort a

Group 1 (n = 126)

Group 2 (n = 125)

Group 3 (n = 128)

Group 4 (n = 125)

Group 5 (n = 126)

Operative Variable

P Value

Emergency

0

1 (0.8)

1 (0.8)

0

0

.56

Total operative time, mean (SD), min

400.0 (123.8)

472.5 (37.4)

553.1 (38.1)

636.6 (38.4)

817.0 (118.7)

<.001

Wound class Clean

25 (19.8) 90 (71.4)

32 (25.6) 88 (70.4)

29 (22.7) 95 (74.2)

22 (17.6) 99 (79.2)

22 (17.5) 96 (76.2)

Clean or contaminated

.09

Contaminated Dirty or infected

9 (7.1) 2 (1.6)

3 (2.4) 2 (1.6)

1 (0.8) 3 (2.3)

0

5 (4.0) 3 (2.4)

4 (3.2)

ASA class 1

2 (1.6)

0

1 (0.8)

0

2 (1.6)

2 b

21 (16.7) 92 (73.0)

29 (23.4) 86 (69.4)

18 (14.1) 93 (72.7) 16 (12.5)

23 (18.4) 95 (76.0)

29 (23.0) 80 (63.4) 15 (11.9)

.26

3 4

1 (8.7)

9 (7.3)

7 (5.6)

Free flap type Osseous

22 (17.5) [−3.0] 98 (77.8) [2.3] 6 (4.8) [−1.1]

24 (19.2) [−2.6] 96 (76.8) [2.0] 5 (4.0) [−1.5]

36 (28.1) [0.1] 85 (66.4) [−0.6] 7 (5.1) [−0.8]

42 (33.6) [2.1] 76 (60.8) [−1.9] 7 (5.6) [−0.7]

39 (31.0) [3.4] 68 (54.0) [−1.6] 19 (15.1) [4.0]

.009

Nonosseous

<.001

Multiple

.003

Abbreviation: ASA, American Society of Anesthesiologists. a Groups 1 through 5 are based on mean (SD) anesthesia times: group 1, 358.1 (175.6) minutes; group 2, 563.2 (27.3) minutes; group 3, 648.9 (24.0) minutes; group 4, 736.5 (26.3) minutes; and group 5, 922.1 (128.1) minutes. Data are

presented as number (percentage) of patients unless otherwise indicated. The χ 2 adjusted residuals are reported in brackets for statistically significant variables with significant residuals greater than 1.96. b Data are missing for 1 patient in group 2.

onstrating a significant difference in the distribution of obe- sity across cohorts (36 [28.8%] in group 5 vs 24 [19.1%] in group 1, P = .007). Adjusted residual values indicate that obesitywas associated with the longest durations of anesthesia in group 5 (Table 1). On extreme value analysis comparing only group 1 and group 5, higher rates of obesity were significantly associ- ated with increased anesthesia duration (24 [19.1%] in group 1 vs 36 [28.2%] in group 5, P = .048). Mean body mass index and specificWorldHealthOrganizationobesity categorieswere not associated with increased or decreased anesthesia dura- tion. Preoperative albumin level andhematocritwerenot found to be associated with increased or decreased anesthesia du- ration. Univariate analysis of the rates of 19 different preopera- tive comorbidities across all quintiles (Table 1) demonstrated no associations between comorbidities and increased or de- creased anesthesia duration. Operative Variables The mean (SD) total operative time was greatest in group 5 (817.0 [118.7]minutes) and lowest ingroup 1 (400.0 [123.8]min- utes). This trendwas positively linear across all quintiles, and increased operative timewas significantly associatedwith in- creased anesthesia duration (mean [SD] operative time, 400.0 [123.8] minutes in group 1 vs 817.0 [118.7] minutes in group 5; P < .001) (Table 2). American Society of Anesthesiologists class 3 or 4, nonclean surgical wound, and emergency status of the operationwere not associatedwith increased or decreased an- esthesia duration. Cases that involved a single osseous free flap operation were associated with a positively linear increase in anesthesiaduration (22 [17.5%] ingroup 1 vs 39 [31.0%] ingroup 5, P = .009), with adjusted residual values most significant in

Results A total of 630 patients undergoing head and neck free flap sur- gery from the 2005-2013 NSQIP database had available data on anesthesia duration andwere included in the study (mean [SD] age, 61.6 [13.8] years; 436 of 629 [69.3%]male). These pa- tients were ranked based on anesthesia duration and strati- fied into 5 quintiles. Mean (SD) anesthesia time ranged from 358.1 (175.6)minutes ingroup 1 to922.1 (128.1)minutes ingroup 5. The variability was notably less in groups 2 to 4, withmean (SD) anesthesia durations of 563.2 (27.3) minutes in group 2, 648.9 (24.0) minutes in group 3, and 736.5 (26.3) minutes in group 4 (eFigure in the Supplement). Preoperative Demographics and Comorbidities No linear trend in ages was found across the quintiles, as dem- onstrated in groups 2 to 4, and age overall was not associated with increased or decreased anesthesia duration (Table 1). Of the entire population, 436 patients (69.3%) were male. This male-dominant trend held true in all 5 quintiles, and therewas no significant difference in the rate of patient sex across quin- tiles (87 [69.0%] men in group 1, 85 [68.0%] in group 2, 84 [65.6%] in group 3, 91 [72.8%] in group 4, and 89 [71.2%] in group5 [of 125with sexdata available]; P = .08) (Table 1).White was the most common race, accounting for 435 (85.1%) of all patients in the analysis, followed by black race (43 [8.4%]) and other races (33 [6.5%]). A total of 119 patients had reported un- known race and were not included in statistical analysis. On χ 2 analysis, the distribution of these races was not associated with anesthesia duration (Table 1). The rate of obesity was greatest in group 5 and lowest in group 1, with χ 2 analysis dem-

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