Predictors of postoperative systemic inflammatory response syndrome after scoliosis surgery in adolescents with cerebral palsy: A retrospective analysis.

Background: Systemic inflammatory response syndrome (SIRS) is known to complicate postsurgical intensive care patients. We noticed that roughly half children with cerebral palsy who undergo posterior spinal fusion (PSF) for neuromuscular scoliosis developed SIRS in the intensive care unit. There is a paucity of literature detailing the impact of intraoperative causes of postoperative SIRS and downstream consequences in these patients. Study purpose was to understand the factors associated with SIRS in children who undergo PSF for neuromuscular scoliosis.
Methods: This retrospective, case control study included children who underwent PSF for neuromuscular scoliosis. Patients with idiopathic scoliosis, osteogenesis imperfecta, and tracheotomy were excluded. Subjects were divided into two study groups based on the diagnosis of SIRS in the intensive care unit. Descriptive statistical analysis was used to identify factors associated with SIRS; a regression analysis was used to further evaluate the independent and significant influence of these factors.
Results: There was no significant difference in the demographic and other preoperative variables. However, total blood products (ml/kg) administered was significantly higher among the SIRS group compared with the non-SIRS group (54.4±41.0 vs 34.1±21.5 P <0.034). Percent of patients remaining intubated was greater in the SIRS group compared with the non-SIRS group (44.1% vs 7.0%, P < 0.001). The regression model revealed that the odds to develop SIRS in patients who were not extubated were 7.467-fold higher (CI: 1.534-36.347) compared with those who were extubated (p=0.013). Conclusions: The incidence of SIRS is significantly higher among the patients who were not extubated at the end of PSF surgery. Further prospective studies are needed to look at the factors that impede the ability to extubate these patients at the end of surgery.

Background

Children with cerebral palsy who undergo posterior spinal fusion (PSF) for neuromuscular scoliosis have significant comorbidities such as chronic lung disease, seizures, poor nutrition, and recurrent urinary tract infection [1,2]. In the past decade, there have been significant improvements in preoperative optimization in terms of lung function, nutrition, and seizure control [1,3]. Despite progress in anesthetic management and surgical technique, the postoperative morbidity continues to be high in this population when compared with PSF for idiopathic scoliosis [4], [5], [6], [7].

Posterior spinal fusion in children with neuromuscular scoliosis is associated with significant blood loss due to inadequate nutrition leading to deficiency of coagulation factors and abnormality of the vascular connective tissue [8], [9], [10]. As a result, intraoperative fluid management often involves transfusion of large volumes of crystalloids and blood products. In recent years, transfusion practices have improved with limitation of crystalloid, balanced transfusion of blood products with a higher ratio of fresh frozen plasma (FFP), packed red blood cell (PRBC), and the use of anti-fibrinolytics to limit blood loss [11,12]. While these measures have had a beneficial impact on the intraoperative course, little is known about the impact of these changes on the immediate postoperative course in terms of morbidity and mortality [5].

Systemic inflammatory response syndrome (SIRS) is defined as the presence of two or more of the following abnormalities: a core temperature of >38.5°C or <36°C; tachycardia, defined as a mean heart rate more than two standard deviations above normal for age; mean respiratory rate more than two standard deviations above normal for age or mechanical ventilation for an acute pulmonary process; and leukocyte count elevated or depressed for age or >10% immature neutrophils [13]. The diagnosis of SIRS and its impact on the postoperative course has been well described after cardiac surgery and in children who undergo emergent intestinal surgeries [14], [15], [16]. The combination of significant fluid shifts, blood transfusions, and surgical tissue trauma place patients who undergo major surgery at higher risk of developing SIRS during the postoperative period [17]. We have noticed an increased incidence in the diagnosis of SIRS in our neuromuscular spine fusion population admitted to the pediatric intensive care unit (PICU).

The objective of this study was to examine the effect of preoperative patient factors and intraoperative anesthetic management on the incidence of SIRS during the postoperative period. We aimed to retrospectively examine the impact of fluid management, transfusion practices, the decision to extubate on the development of SIRS, and the effect on length of stay in the PICU.

Methods

This study was approved by the Institutional Review Board. This was a retrospective study undertaken at a tertiary-care children's hospital in the mid-Atlantic region of United States. The study included patients who underwent PSF for neuromuscular scoliosis over a three-year period from 2017 to 2019. Patients with idiopathic scoliosis and scoliosis due to osteogenesis imperfecta and with tracheostomy were excluded.

Patient data were extracted from hospital electronic medical and anesthetic records (EPIC Systems, Verona WI). The preoperative data elements included basic demographics such as age; sex; weight; diagnosis such as degree of Cobb angle; presence of kyphosis, seizures or on medication for suspected seizures, functional status of patients such as ability to verbalize, feed and ambulate; and gross motor function classification system (GMFCS) scores as appropriate for the diagnosis and type of surgery. The GMFCS level 5 subclassification based on the number of neuromotor impairments was not analyzed as a variable; however, each individual impairment (gastrostomy tube, seizures, and nonverbal status) was collected separately and analyzed as a variable. The intraoperative data elements included duration of surgery, amount of blood loss, amount of crystalloid administered, amount of various blood components administered including FFP, PRBC, platelets and cryoprecipitate, lowest hemoglobin and successful extubation at the end of surgery. The postoperative data consisted of the diagnosis of SIRS in the intensive care unit (ICU), percentage of patients who received crystalloid in the first 24 and 48 hours, percentage of patients who received blood products in the first 48 hours, use of vasopressors in the first 48 hours, intubation days, length of intensive care stay, length of hospital stay, and the incidence of wound infection.

Diagnosis of SIRS in our ICU was based on the standard criteria of the presence of two or more of the following abnormalities 1) core temperature, measured by rectal, bladder, oral, or central probe >38.5°C or <36°C, 2) tachycardia, defined as a mean heart rate more than two standard deviations above normal for age, or for children younger than one year of age, bradycardia, defined as a mean heart rate <10th percentile for age, 3) mean respiratory rate more than two standard deviations above normal for age, 4) mechanical ventilation for an acute pulmonary process, 5) leukocyte count elevated or depressed for age, or >10 percent immature neutrophils. The time for diagnosis of SIRS was limited to 48 hours to truly know the impact of the intraoperative and preoperative factors over the incidence of SIRS in the ICU.

Analysis

Continuous variables were expressed as means ± standard deviation, and categorical variables were a percent of an outcome in a group. Univariate analysis was conducted to compare the differences of the preoperative, intraoperative, and postoperative variables between SIRS and non-SIRS groups. The t-test was performed for continuous variables and the chi-square contingency for categorical variables to evaluate statistical significance between the two groups. Continuous variables with wide distributions were transformed to Log10 prior to analysis to obtain p values, but raw means were calculated and presented in the results. In addition, the logistic regression analysis was conducted to identify risk factors independently contributing to the development of SIRS. Variables relevant to the SIRS outcome or which showed significant differences in univariable analysis were included in the regression model.

Statistical analysis was performed using the SPSS statistical software system (SPSS Version 27, IBM, Armonk, NY USA). P<0.05 was considered significant.

Results

Univariable analysis of variables between SIRS and non-SIRS

After the electronic medical records of the intraoperative anesthesia and intensive care documentation were reviewed, a total of 77 patients met the criteria and were included in the study. The patients were divided into 2 groups based on the incidence of SIRS in the intensive care unit. We had 34 patients in the SIRS group and 43 patients in the non-SIRS group.

The SIRS and non-SIRS groups had similar demographic and clinical conditions preoperatively. No significant differences were found in terms of degree of scoliosis, type of surgery, feed status, and seizures or on medication for suspected seizures (Table 1). The percent of patients with GMFCS Score ≥5 was 85.3% in the SIRS group, which was higher but not significantly when compared with the non-SIRS at 69.8% (Table 1; p=0.091). On the other hand, 17.6% patients in the SIRS group had intact verbal function comparing with 34.9% in the non-SIRS group, but the difference was not significant (Table 1; p=0.075).

Table 1

Comparison of patients with and without systemic inflammatory response syndrome.

	SIRS (N=34)	Non-SIRS (N=43)	P Value
Demographic, medical conditions variables:
Gender (M/F)	15/19	18/25	0.513
Age	13.4±2.7	12.8±3.4	0.383
Weight	36.7±13.0	34.7±10.6	0.459
% with Unit rod surgery	58.8% (20)	51.2% (22)	0.330
% with kyphosis	38.2% (13)	34.9% (15)	0.473
% of GMFS Score ≥5	85.3% (29)	69.8% (30)	0.091
Verbal %	17.6% (6)	34.9% (15)	0.075
G Tube %	67.6% (23)	55.8% (24)	0.206
Seizures %*	64.7% (22)	55.8% (24)	0.578
Intra-operative variables
Surgery Time (Minutes)	413.7±164.6	349.3±136.5	0.099
Blood loss (ml/Kg)	40.7±26.9	31.5±22.4	0.058
Total crystalloid (ml/Kg)	80.7±38.9	73.5±32.5	0.419
Total blood products (ml/kg)	54.4±41.0	34.1±21.5	0.034
PRBC (ml/kg)	25.5±19.4 (26)	16.4±8.2 (28)	0.106
FFP (ml/kg)	20.9±14.7 (33)	13.9±6.7 (37)	0.074
FFP/PRBC Ratio	1.13±0.58 (26)	1.05±0.54 (24)	0.496
Cell saver (ml/kg)	13.7±9.1 (26)	11.9±8.5 (38)	0.215
% Received Platelets	44.1 % (15)	11.6% (5)	0.002
Lowest hemoglobin	9.7±1.7	10.1±1.5	0.305
% Vasopressor in OR	41.2% (14)	30.2% (13)	0.224
% of not extubated in OR	44.1% (15)	7.0% (3)	<0.001
Post-operative and ICU variables
% bolus crystalloid 24	82.4% (28)	34.9% (15)	<0.001
% PRBC transfusion POD 1 and/or POD2	26.5% (9)	9.3% (4)	0.046
Circulatory support with inotropes	50.0% (17)	4.7% (2)	<0.001
Intubated ≥1 day	44.1% (15)	9.3% (4)	0.001
ICU >2 days (range:0.5-15 days)	64.7% (22)	30.2% (13)	0.003
Hospital days >8 (range: 2-85 days)	50.0% (17)	39.5% (17)	0.551
% Transfusion 48 hours and discharge	11.8% (4)	11.65 (5)	0.628
Wound infection at discharge	2.9% (1)	9.35 (4)	0.261

SIRS: systemic inflammatory response syndrome, GMFCS: Gross Motor Function Classification System, G Tube: gastrostomy tube, Total blood products including FFP, PRBC, cell saver, platelets, and cryoprecipitate. FFP: fresh frozen plasma, PRBC: packed red blood cell, POD1 and POD2: postoperative day 1 and day 2, ICU: Intensive Care Unit.

*Had seizures or on medication for suspected seizures.

There were no significant differences in the surgery time, blood loss, and crystalloid administration between the two groups. The total for blood products administered was significantly higher in the SIRS group than the non-SIRS group, but the difference was not significant when analyzed by individual component or the ratio (FFP/PRBC) except for platelets (Table 1). A greater percentage of patients received platelets in the SIRS group when compared with the non-SIRS group (38.9% vs 11.6%, p = 0.002). There were no differences seen in the lowest hemoglobin or the percent of patients requiring vasopressors. However, the percent of patients remaining intubated was greater in the SIRS group when compared with the non-SIRS group (44.1% vs 7.0%, p < 0.001).

In the ICU, more patients in the SIRS group received crystalloid boluses in the first 24 hours than in the non-SIRS group (82.4% vs 34.9%, p < 0.001). In addition, the proportion of patients who received PRBC transfusion at postoperative day 1 (POD1) and/or day 2 (POD2) was slightly but significantly higher in the SIRS group than in the non-SIRS group (26.5% vs 9.3%; p = 0.046). When compared with the non-SIRS patients, more patients in the SIRS group required circulatory support with inotropes (50% vs 4.7; p<0.001), remained intubated ≥1 day (44.1% vs 9.3%, p=0.001), and stayed >2 days in the ICU (64.7% vs 30.2%, p=0.003). The hospital stay had a wide range from 2 to 85 days with a median 8 days in the entire cohort. There were no differences in the proportion of patients staying greater than 8 days between the two groups, and similarly, no difference in the transfusions received between 48 hours and discharge or the incidence of wound infections (Table 1).

Analysis of variables between extubated and non-extubated patients

In the study cohort, 59 patients were extubated at the end of surgery while 18 continued to be intubated. We compared pre-, intra-, and postoperative data between the extubated and non-extubated patients (Table 2). No demographic, medical diagnosis and preoperative data were found to be different between the extubated and non-extubated groups; however, slightly but significantly more patients in the non-extubated group had GMFCS score ≥ 5 (94.4% vs 71.2%; p = 0.035; Table 2). Those who remained intubated were associated with substantially longer surgery time, more blood loss, and received more blood products and crystalloid compared with the extubated group (p<0.05). Similar patterns were observed when comparing the blood product types, though there was no difference in the FFP/PRBC ratio comparison (Table 2). The lowest hemoglobin level in the operating room (OR) in the non-extubated group was slightly but significantly lower than the extubated group (p=0.03; Table 2). The proportion of patients requiring vasopressors in the OR was higher in the non-extubated group at 55.6% than the extubated group at 28.8% (p = 0.038). Postoperatively, the non-extubated group was significantly associated with receiving bolus crystalloid at 24 hours, SIRS, circulatory support with inotropes, intubation duration ≥1 day, ICU stay >2 days, and hospital stay >8 days (p < 0.05). The variables of PRBC transfusion POD 1 and/or POD2, transfusion between 48 hours and discharge, and wound infection displayed no difference among the extubated and the non-extubated groups (p > 0.05).

Table 2

Comparison of patients extubated and not extubated in the operating room.

	Non-Extubated (N=18)	Extubated (N=59)	P Value
Demographic, medical conditions variables:
Gender (M/F)	10/8	23/36	0.166
Age	12.2±2.5	13.3±3.2	0.203
Weight	34.6±14.1	35.9±11.0	0.688
Unit rod surgery %	61.1% (11)	52.5% (31)	0.358
% with Kyphosis	44.4% (8)	33.9% (20)	0.294
GMF Score ≥5 %	94.4% (17)	71.2% (42)	0.035
Verbal %	16.7% (3)	30.5% (18)	0.200
G Tube %	72.2% (13)	57.6% (34)	0.203
Intra-operative variables:
Surgery time (Minutes)	472.4±164.7	341.0±121.2	0.001
Estimated blood loss (ml/Kg)	51.8±27.8	30.7±21.7	0.001
Total blood products (mg/Kg)	74.8±39.9	33.3±23.5	<0.001
Total crystalloid (mg/Kg)	102.0±44.4	69.0±28.3	0.001
% Received Platelets	72.2% (13)	11.9% (7)	<0.001
PRBC (ml/kg)	30.8±18.5 (17)	16.2±11.1 (37)	0.001
FFP (ml/kg)	28.6±13.9 (16)	13.9±8.5 (54)	<0.001
FFP/PRBC Ratio	1.1±0.5 (16)	1.1±0.6 (34)	0.762
Cell saver (ml/kg)	18.6±10.5 (14)	11.0±7.5 (50)	0.003
Lowest Hgb in OR	9.3±1.7	10.2±1.5	0.030
% Vasopressor in OR	55.6% (10)	28.8% (17)	0.038
Post-operative and ICU variables:
% Bolus Crystalloid 24	77.8% (14)	49.2% (29)	0.029
SIRS	83.3% (15)	32.2% (19)	<0.001
% PRBC transfusion POD 1 and/or POD2	16.7% (3)	16.9% (10)	0.644
% Transfusion 48 hours and discharge	16.7% (3)	10.1% (6)	0.351
Circulatory support with inotropes	66.7% (12)	11.9% (7)	<0.001
Intubated ≥1 day*	94.4% (17)	3.4% (2)	<0.001
ICU >2 days (range:0.5-15 days)	83.3% (15)	33.9% (20)	<0.001
Hospital days >8 (range: 2-85 days)	72.2% (13)	42.4% (25)	0.025
Wound infection at discharge	11.1% (2)	5.1% (3)	0.332

SIRS: systemic inflammatory response syndrome, GMFCS: Gross Motor Function Classification System, G Tube: gastrostomy tube. Total blood products including FFP, PRBC, cell saver, platelets, and cryoprecipitate. FFP: fresh frozen plasma, PRBC: packed red blood cell, POD1 and POD2: postoperative day 1 and day 2, ICU: Intensive Care Unit. *One patient in the non-extubated in OR group was extubated less than 24 hours in ICU, and two extubated cases in OR were reintubated in the ICU.

Regression analysis of SIRS risk factors

A regression analysis was conducted to discover variables that could independently predict the risk of SIRS in the ICU (Table 3). Only pre- and intraoperative variables that presented differences between SIRS and non-SIRS groups and with p value <0.1 were included in the analysis. Blood product types were not analyzed separately but as the total amount of blood products received during the surgery. Postoperative and ICU variables that exhibit differences as the results of SIRS also were not included. The regression model reveals the odds of developing SIRS in patients who were not extubated were 7.467-fold higher (CI: 1.534-36.347) compared with those who were extubated (p=0.013, Table 3). No other pre- or intraoperative factors were significantly associated with SIRS when the effects from other variables were controlled.

Table 3

Logistic analysis of risk factors associated with systemic inflammatory response syndrome.

Independent Variables	Estimated Coefficient	P	Odds Ratio	95% CI
				Lower	Upper
% GMF Score ≥5	0.074	0.918	1.077	0.26	4.460
% of Verbal	0.784	0.247	2.19	0.581	8.264
Surgery Time (Minutes)	0.738	0.679	2.091	0.063	69.028
Estimated Blood Loss (ml/Kg)	0.073	0.966	1.075	0.039	29.289
Total Blood Products (ml/kg)	0.484	0.755	1.622	0.077	34.006
Not Extubated in OR	2.01	0.013	7.467	1.534	36.347
Constant	-4.018	0.404	0.018

SIRS: systemic inflammatory response syndrome, CI: confidence interval for odds ratio, GMFCS: Gross Motor Function Classification System

Discussion

To our knowledge, this is the first study that examines factors associated with SIRS and the postoperative morbidity in children who underwent PSF for neuromuscular scoliosis. We found that inability to extubate the patient at the end of surgery was highly correlated with a higher risk of developing SIRS in the ICU. Further, the factors associated with the inability to extubate were largely correlated with blood loss, increased transfusions, and crystalloid administration, as might be expected. The patients who developed SIRS in the ICU needed significantly more crystalloid and inotropic support during the first 24 or 48 hours. In addition, the patients who had SIRS had more intubation days and longer PICU stays compared with the patients who did not develop SIRS in the ICU. Our findings suggest that overall, efforts to ensure extubation at the end of surgery by perhaps adopting restrictive transfusion practices may decrease the incidence of postoperative SIRS.

The incidence of SIRS in the PICU is highly variable from as low as 16.7% after distal pancreatic resections to as high as 68% to 82% in the mixed PICU as has been shown in some past studies [15,18,19]. In our study, we found the incidence of SIRS to be 44% (34 of 77) after PSF for neuromuscular scoliosis in our patient population. The etiology of SIRS in the PICU varies with the type of ICU and distribution of the admitted patient population. The medical PICU, where the admission of patients is through the emergency department or from the patient floor, have been shown to have higher prevalence of SIRS due to sepsis and trauma. On the other hand, surgical PICU had a higher prevalence due to stress response to the surgery [19]. The pathophysiology, severity, and course of SIRS after sepsis and septic shock has been well documented in the literature. However, there is paucity of literature about the epidemiology and consequences of SIRS after major surgery such as PSF in the pediatric population. The majority of the literature about SIRS in the pediatric surgical population refers to post cardiac surgery.

In the past, SIRS and severe sepsis have been used interchangeably among patients who developed shock with signs and symptoms suggestive of inflammation. But, in the last decade, studies have provided evidence that all patients with SIRS should not be assumed to have infection or bacteremia [20,21]. The clinical entity of SIRS could develop as a response to perioperative inflammatory process in patients who undergo major surgery and to other sources of inflammation such as trauma, infection, or burns. The source of perioperative inflammatory process could be due to a duration of surgery longer than 4 hours, extent of tissue trauma, the size of the wound, the amount of blood loss and transfusions, and the particular anesthetic regimen or perioperative medications [17]. In our study cohort, the mean duration of surgery in our study was 372 minutes, and the average blood loss was 36ml per kilogram. Subsequently, they received 43ml per kilogram of blood products and 77ml per kilogram of crystalloids during the surgery. Thus, longer duration of surgery, significant blood loss, and high-volume resuscitation with both crystalloids and blood products in our study placed our patients at a higher risk of developing SIRS.

Intraoperative erythrocyte transfusion alone has been implicated in the development of SIRS in the ICU [22], [23], [24]. In one study published from a large National Surgical Quality Improvement Program (NSQIP) database, the authors found a significant association between the amount of intraoperative blood transfusion and increased incidence of SIRS in the postoperative period [25]. There are multiple studies in the adult literature that demonstrate liberal erythrocyte transfusion associated with increased risk of postoperative morbidity and mortality [[22], [23], [24],26,27]. The mechanism by which blood transfusion increases the morbidity and mortality is not clear. But the most likely explanation is the tendency of erythrocyte transfusion to cause erythrocyte-induced immunomodulation with subsequent immune activation and transfusion-related lung injury [28,29]. This theory is substantiated by evidence of decrease in the mortality and morbidity with the leukocyte reduction and use of fresh erythrocyte for transfusion [30,31].

In our univariate analysis, we found that patients who were in the SIRS group received significantly higher amounts of total blood products in the OR compared with patients in the non-SIRS group (54.4±41.0 vs 34.1±21.5 ml/kg). Differences were noted, though not significantly, when analyzed by blood product components PRBC and FFP. Only a fraction of patients received platelets: 44.1% (15 of 34) in the SIRS group, which was significantly higher than 11.6% (5 of 43) in the non-SIRS group (P = 0.002). Our univariable analysis agreed with these previous studies, hinting that blood transfusion could be one of the risk factors for SIRS. However, in the regression analysis, we found the inability to extubate at the end of surgery was a significant and independent predictor of SIRS and the blood transfusion was no longer a strong predictor for SIRS. In the past, children who underwent PSF for neuromuscular scoliosis were not extubated at the end of surgery due to high blood volume loss, massive blood transfusion, long duration of the surgery, and medical complexity of this patient population [32,33]. Our data showed that patients who were not extubated had significantly longer surgery, lost more blood, and received more blood products when compared with those who were extubated. The delayed extubation at the end of surgery has been shown to increase postoperative pneumonia in adults who underwent multilevel spine surgery [33,34]. Further, in a large database query from the American College of Surgeons National Surgical Quality Improvement Program revealed that failure to extubate at the end of surgery and delayed re-intubation in the ICU was associated with significantly higher overall morbidity, mortality and longer hospital stays for adult patients who underwent spine surgery [35].

The improvement of surgical technique and anesthetic management of minimizing blood loss along with markedly improved transfusion strategies such as mimicking a whole blood transfusion has significantly reduced the blood loss in PSF [12]. However, despite these improvements, extubation of patients at the end of surgery is often dictated by the local hospital traditions and judgement of the individual anesthesia practitioners. The benefit of delaying extubation in OR has not been fully examined regarding SIRS development in children who underwent PSF for neuromuscular scoliosis. In our analysis, we found a significant percentage of patients who were in the SIRS group were not extubated at the end of surgery compared with the non-SIRS group, and the odds of developing SIRS in our patients increased by seven-fold if the patients were not extubated at the end of the surgery. It could be that the patients who were not extubated at the end of surgery may be sicker with complex pre- and intraoperative courses. In our sub-analysis, no differences were found in preoperative variables among the extubated and non-extubated groups. Nevertheless, our data demonstrate the same association between delayed extubation in the OR and postsurgical complications as reported in adult studies [35]. It is also likely the prevailing PICU management may contribute to the delayed extubation in that often, intubated patients are sedated, receive additional crystalloid, and are put on inotropes for blood pressure issues. We need prospective studies in the future to better understand the risk factors of the failure to extubate at the end of surgery and the effect of the failure to extubate on the postoperative morbidity and mortality and contribution from inflammatory cytokines induced by spine fusion in patient with neuromuscular scoliosis.

Finally, the development of postoperative SIRS has been known to increase the mortality and morbidity of the surgical patients. It has been shown in the past that the patients with SIRS tend to have longer ventilator days, longer ICU and hospital days, and a higher mortality rate [16,21,36]. This is consistent with our patients who had SIRS in the ICU, as they had a longer duration of mechanical ventilation, and a higher percentage of patients stayed longer than 2 days in ICU and longer than 8 days in the hospital when compared with patients in the non-SIRS group.

The primary limitation of our study is that it is a retrospective study with data collection that relied upon completeness of the initial data entries. The patients were labelled as SIRS in our ICU chart by the intensivist and intensive care fellows based on a review of the vital signs at any time point during the first 24 hours. At present, our ICU does not have a protocol to check the persistence of SIRS in the electronic medical record at regular time intervals. So, we do not have the data of the duration of the course of SIRS in the ICU. Secondly, the decision to extubate the patient at the end of surgery was made based on the judgement of the individual practitioners as there was universally excepted extubation criteria. Based on this study, it may be necessary to develop specific criteria for extubation, formal documentation of SIRS at regular time intervals, and fast-track extubation of these patients in the ICU as feasible.

Conclusion

The incidence of SIRS is significantly higher among the patients who were not extubated at the end of surgery. Thus, we conclude that failure to extubate the patient at the end of surgery may have significant impact over the morbidity of the patient after PSF for neuromuscular scoliosis. In the future, we need prospective studies to look at the factors that impede the ability to extubate these patients at the end of surgery.

Funding

No funding to report.

Declaration of Competing Interest

The authors declare they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.