Gastroenterol Res

Gastroenterology Research, ISSN 1918-2805 print, 1918-2813 online, Open Access

Article copyright, the authors; Journal compilation copyright, Gastroenterol Res and Elmer Press Inc

Journal website https://www.gastrores.org

Original Article

Volume 14, Number 3, June 2021, pages 157-164

Efficacy and Safety of Neostigmine and Decompressive Colonoscopy for Acute Colonic Pseudo-Obstruction: A Single-Center Analysis

Figure 1. Patient flow and treatments for management of ACPO. A total of 515 cases in 508 patients (as some patients had repeat hospitalizations for ACPO) were initially identified. Some excluded patients did receive neostigmine or underwent colonoscopy during their hospitalization. Excluded patients receiving neostigmine: intra-abdominal malignancy (n = 1), cecum < 10 cm or no stated measurement (n = 4 in 4 patients), CIPO (n = 5 in 3 patients) for a total of 10 episodes in 8 patients. Excluded patients undergoing colonoscopy: confirmed bowel obstruction (n = 3 in 3 patients), intra-abdominal malignancy (n = 2 in 2 patients), cecum < 10 cm or no stated measurement (n = 11 in 11 patients), CIPO (n = 7 in 4 patients) for a total of 23 episodes in 20 patients. Among included cases (n = 46 in 42 patients), all but one patient who underwent a colonoscopy initially received supportive care. Because this patient underwent colonoscopy, they were included in the group of cases that received colonoscopy first. In the group of cases that received supportive care (n = 45 in 41 patients), there was one patient who responded to supportive care alone during one hospitalization and required neostigmine during a second hospitalization. This patient and their demographic information at time of hospitalization was included in both the group of cases receiving neostigmine first as well as in the group of cases responding to supportive care alone. ACPO: acute colonic pseudo-obstruction.

**Table 1.** Patient Characteristics
	Neostigmine tried first (%) (n = 15)	Colonoscopy tried first (%) (n = 24)	Received only supportive care (%) (n = 7)	Total population (%) (n = 46)
MI: myocardial infarction.
Mean age (range), years	56.2 (20 - 92)	72.2 (51 - 93)	73.14 (52 - 87)	67.1 (20 - 93)
Sex (male, female)	86.67, 13.33	79.17, 20.83	71.43, 28.57	80.4, 19.57
Ethnicity
White	60	66.67	57.14	63.04
African-American/Black	20	20.83	42.86	23.91
Hispanic	0	4.17	0	2.17
Asian/Pacific Islander	6.67	0	0	2.17
Alaskan Native/American Indian	0	0	0	0
Other/declined to answer	13.33	8.33	0	8.7
History of dementia	26.67	20.83	28.57	23.91
History of MI	13.33	12.50	14.29	13.04
History of ischemic stroke	46.67	37.50	28.57	39.13
History of neuromuscular disease	20	25	0	19.57
Sepsis	33.33	20.83	0	21.74
Received opiates	20	50	28.57	36.96
Surgery in the past 2 weeks	33.33	45.83	42.86	41.30

Table 1. Patient Characteristics

Neostigmine tried first (%) (n = 15)

Colonoscopy tried first (%) (n = 24)

Received only supportive care (%) (n = 7)

Total population (%) (n = 46)

MI: myocardial infarction.

Mean age (range), years

56.2 (20 - 92)

72.2 (51 - 93)

73.14 (52 - 87)

67.1 (20 - 93)

Sex (male, female)

86.67, 13.33

79.17, 20.83

71.43, 28.57

80.4, 19.57

Ethnicity

White

66.67

57.14

63.04

African-American/Black

20.83

42.86

23.91

Hispanic

4.17

2.17

Asian/Pacific Islander

6.67

2.17

Alaskan Native/American Indian

Other/declined to answer

13.33

8.33

8.7

History of dementia

26.67

20.83

28.57

23.91

History of MI

13.33

12.50

14.29

13.04

History of ischemic stroke

46.67

37.50

28.57

39.13

History of neuromuscular disease

19.57

Sepsis

33.33

20.83

21.74

Received opiates

28.57

36.96

Surgery in the past 2 weeks

33.33

45.83

42.86

41.30

**Table 2.** Use and Efficacy of Initial Neostigmine Trial in ACPO (N = 15 Episodes in 12 Patients)
^aPositive response was defined as documentation of passage of flatus, relief of symptoms, decrease in abdominal distention, or decrease in colon diameter on imaging. ^bOne patient had a positive response after receiving neostigmine three times. One patient who initially underwent colonoscopy ultimately had a response to two doses of neostigmine. ^cOne patient eventually underwent an elective surgery for persistent symptoms. ACPO: acute colonic pseudo-obstruction; IV: intravenous.
Total rate of positive response (%)^a	13/15 (86.67%)
Rate of positive response after first dose	9/15 (60%)
Rate of positive response after second dose	4/5 (80%)^b
Number of hours between imaging findings and intervention	Median 20 h, average 44.86 h
Average cecal diameter at time of diagnosis (cm)	13.3
Average change in cecal diameter in responders (cm)	3.11 (median 2.3)
Range of dose	0.5 - 4.5 mg IV bolus
Rate of positive response to colonoscopy (performed after neostigmine failed)	3/3
Surgery required for ischemia or perforation	0/15^c

Table 2. Use and Efficacy of Initial Neostigmine Trial in ACPO (N = 15 Episodes in 12 Patients)

^aPositive response was defined as documentation of passage of flatus, relief of symptoms, decrease in abdominal distention, or decrease in colon diameter on imaging. ^bOne patient had a positive response after receiving neostigmine three times. One patient who initially underwent colonoscopy ultimately had a response to two doses of neostigmine. ^cOne patient eventually underwent an elective surgery for persistent symptoms. ACPO: acute colonic pseudo-obstruction; IV: intravenous.

Total rate of positive response (%)^a

13/15 (86.67%)

Rate of positive response after first dose

9/15 (60%)

Rate of positive response after second dose

4/5 (80%)^b

Number of hours between imaging findings and intervention

Median 20 h, average 44.86 h

Average cecal diameter at time of diagnosis (cm)

13.3

Average change in cecal diameter in responders (cm)

3.11 (median 2.3)

Range of dose

0.5 - 4.5 mg IV bolus

Rate of positive response to colonoscopy (performed after neostigmine failed)

3/3

Surgery required for ischemia or perforation

0/15^c

**Table 3.** Use and Efficacy of Initial Trial of Decompressive Colonoscopy in ACPO (N = 24 Episodes in 24 Patients)
^aPositive response was defined as documentation of passage of flatus, relief of symptoms, decrease in abdominal distention, or decrease in colon diameter on imaging.^bIn one episode, hypoxia occurred during colonoscopy and although the procedure was aborted, a decompression tube was placed and the colonoscopy was considered complete. ^cBowel perforation occurred in one patient who underwent colonoscopy, 2 weeks after the procedure. ACPO: acute colonic pseudo-obstruction.
Total rate of positive response (%)^a	23/24 (95.8%)
Rate of positive response after first colonoscopy (%)	22/24 (91.6%)
Number of hours between imaging findings and intervention	Mean 39.92 h, median 33 h
Average cecal diameter at time of diagnosis (cm)	12.53
Mean change in cecal diameter in responders (cm)	3.68 (median 3.55)
Ischemia present at time of scope	4/24 (16.67%)
Obstruction present at time of scope	0/24
Peri-procedure complications (%)	1/24 (4.17%)^b
Rate of bowel perforation (%)	0/24^c
Surgery required for persistent symptoms (%)	1/24 (4.17%)
Patients in whom neostigmine was considered contraindicated	16/24 (67%)

Table 3. Use and Efficacy of Initial Trial of Decompressive Colonoscopy in ACPO (N = 24 Episodes in 24 Patients)

^aPositive response was defined as documentation of passage of flatus, relief of symptoms, decrease in abdominal distention, or decrease in colon diameter on imaging.^bIn one episode, hypoxia occurred during colonoscopy and although the procedure was aborted, a decompression tube was placed and the colonoscopy was considered complete. ^cBowel perforation occurred in one patient who underwent colonoscopy, 2 weeks after the procedure. ACPO: acute colonic pseudo-obstruction.

Total rate of positive response (%)^a

23/24 (95.8%)

Rate of positive response after first colonoscopy (%)

22/24 (91.6%)

Number of hours between imaging findings and intervention

Mean 39.92 h, median 33 h

Average cecal diameter at time of diagnosis (cm)

12.53

Mean change in cecal diameter in responders (cm)

3.68 (median 3.55)

Ischemia present at time of scope

4/24 (16.67%)

Obstruction present at time of scope

0/24

Peri-procedure complications (%)

1/24 (4.17%)^b

Rate of bowel perforation (%)

0/24^c

Surgery required for persistent symptoms (%)

1/24 (4.17%)

Patients in whom neostigmine was considered contraindicated

16/24 (67%)