Study of Serum Electrolytes in Surgical Patients Undergoing Intestinal Stoma

Manal M Khan, A K Verma, Shaista M. Vasenwala, Sheeraz M. Khan
**Mr. Abrar Ahmad
All belongs to Jawaharlal Nehru Medical College, Aligarh Muslim University, India
** Statistical Cell, Maulana Azad National Urdu University, Hyderabad, India

INTRODUCTION

Chief electrolytes in the human body are Sodium, Potassium, Calcium, Magnesium, Chloride, Bicarbonate, etc. (Na+, K+, Ca2+, Mg2-, Cl-, HCO3-). The maintenance of optimal function of body physiology depends on proper concentration or proportion of these electrolytes within a narrow normal range. Derangement i.e. excess or depletion of electrolytes in the body leads to derangement of physiological function.

Maintaining fluid and electrolyte balance requires understanding of normal intake and output of major electrolytes required for body economy, including the consideration of abnormal losses of fluids (Intestinal stomas, fistulas, gastric aspiration, drains etc.), their electrolyte content and the deficiencies acquired thereby. An intestinal stoma is an opening of intestinal tract on to the abdominal wall. It mainly functions to divert the faeces and flatus to the exterior. It may be an ileostomy or colostomy depending on the exteriorisation of either ileum or colon respectively. In rare instances, proximal small bowel can be taken out as a jejunostomy.

A stoma may be a low volume stoma, in which daily volume is around 500 ml or a high volume stoma, in which daily volume is one litre or more (Hill et al, 1974). Patients with stoma output less than one litre daily are seldom troubled. On the other hand patients with high output stomas are prone to salt and water depletion. If a significant amount of ileum is resected at the time of an ileostomy operation, output from the resulting ileostomy tends to be unusually profuse (Nuguid et al, 1961, Hill et al, 1974).

The omission of an intestinal stoma may result in morbidity or even mortality - this must be weighed against the physical, metabolic and psychological complications of an ileostomy or colostomy. One of the biochemical parameters is the study of serum electrolytes, namely serum sodium, serum potassium, serum calcium, serum magnesium and serum chloride, in surgical patients undergoing intestinal stoma creation, either ileostomy or colostomy postoperatively.

AIMS AND OBJECTIVES OF THE STUDY
(1) To assess and quantify the serum electrolyte changes in patients following ileostomy/ colostomy.
(2) To identify and estimate need for electrolyte replacement.
(3) To develop a regime for electrolyte supplementation based on the findings of this study, if indicated.
This study was carried out in the postoperative period of surgical patients who underwent stoma creation and who were maintained on intra-venous fluid and electrolyte regime followed in this hospital (dextrose and ringer lactate) until the 3rd postoperative day, and blood transfusion done wherever indicated. However no patient was allowed to go into a fluid deficit.

MATERIALS AND METHODS

This study was conducted on 70 surgical cases admitted in the Department of General Surgery, J.N. Medical College, A.M.U., Aligarh and who went for the creation of intestinal stomas. Clinical examination and investigations i.e. serum sodium, serum potassium, serum calcium, serum chloride and serum magnesium, and quantity of stoma output, were done postoperatively at 24 hrs (1st day), 96 hrs (3rd day) and 120 hrs (5th day). Patients who were below 12 years of age were not included in this study.
Intestinal Stoma Output Quantity in ml

Serum Values: Electrolytes
Serum Sodium: Normal value of serum sodium taken was 135-145 mEq/L or 135- 145 mmol/L
Serum Potassium: Normal values of serum potassium was taken between 3.5-5.0 mEq/L or 3.5-5.0 mmol/L

Serum Calcium: Normal value of serum calcium was 2.1-2.6 mmol/L (8.5-10.5 mg/dL) (conversion factor 0.25) (Young DS, 1987). [Calcium: mmol/L=mEq/Lx0.5=mg/dlx0.25]
Serum Magnesium: Normal value of serum magnesium was taken as 0.75-1.25 mmol/L or 1.8-3.0 mg/dL or 1.4-2.2 mEq/L (Young DS, 1987). [Magnesium: mmol/L =mEq/Lx0.5=mg/dLx0.41]
Serum Chloride: Normal value of serum chloride was taken as 98-107 mmol/L (mEq/L) (Young DS, 1987).

Estimation of Serum Electrolytes (sodium, potassium, magnesium, calcium and chloride) was done.

STATISTICAL ANALYSIS

Processing of data: All the observations have been statistically analyzed. The standard deviation has been calculated using the formula:

The Students -test of significance is applied to test the significance of difference of values between different samples the value of 't' was calculated by the following formula:

where,
= Mean of first sample
= Mean of second sample
S1 = Standard deviation of first sample
S2 = Standard deviation of second sample
n1= Number of cases in first sample
n2 = Number of cases in second sample
The value of 't' and P are seen from the table. The value is less than 0.05 and is considered to be significant.

OBSERVATIONS
The estimation of serum electrolytes, namely serum sodium serum potassium, serum calcium, serum magnesium and serum chloride were done postoperatively at 24 hours (1st postoperative day), 72 hours (3rd postoperative day) and 120 hours (5th postoperative day). During the postoperative study period, two patients expired, one on the 4th and the other on the 5th postoperative day, respectively. All of the patients in this study had their stoma created on operation for emergency conditions.

Table 1: Case Distribution according to Age and Sex

Table 1 reveals that the maximum number of patients were in the 13-25 years of age group i.e. 28 (16 males and 12 female) and the youngest patient was 13 years old and the oldest was 80 years old. The mean age of the patients was 33.14 years. (Males 35.36 years and females 29.82 years).

Table 2: Case distribution according to operative procedure and sex

Table 2 depicts that out of the total 70 patients, 58 patients underwent ileostomy (33 males, 25 females), and out of these 16 patients underwent resection of small bowel in addition to ileostomy (10 males and 6 females). Twelve patients had colostomy (9 males and 3 females) as the operative procedure. Patient having stoma without additional resection of small intestine were 54 (colostomy patients +patients having ileostomy with no resection of small bowel) (32 males and 22 females).

Table 3: Case distribution according to diagnosis

From Table 3 the majority of the patients who underwent stoma creation were of perforation peritonitis 43 (61.6%) patients following typhoid, tubercular or non-specific enteritis. Twenty patients (28.6%) presented with intestinal obstruction, out of these 7 cases had malignancy. Ten cases in addition to obstruction had associated peritonitis (6 cases of adhesion obstruction, 2 of malignancy and one each of caecal and sigmoid volvulus). The remaining 7 cases had stoma creation due to gun shot abdomen (3), septic abortion (2) and rectal and perineal injury (2)

Table 4: Postoperative stoma output (in ml)

From Table 4, the average daily quantity of stoma output in all patients on the 3rd postoperative day was 441.4 ml and on the 5th postoperative day was 641.1 ml. Stoma output on the first postoperative day was not taken into consideration as most of the stomas were not functioning at that time.

The average daily stoma output in patients having stoma with no resection of small bowel was 416.7 ml and 586.8 ml on the 3rd and 5th postoperative days respectively and in patients having ileostomy with resection of small bowel was 525 ml on the 3rd postoperative day and 833.3 ml on the 5th postoperative day.

The average daily stoma output in patients having ileostomy with no resection of small bowel was 476.2 ml on the 3rd day postoperative and 670.7 ml on the 5th postoperative day.

The average daily stoma output in all patients having ileostomy was 489.6 ml on the 3rd postoperative day and 714.3 ml on the 5th postoperative and in patients having colostomy was 208.3 ml on the 3rd postoperative 300 ml on the 5th postoperative day.

Quantity of stoma output between ileostomy and colostomy patients showed a highly significant lower amount in colostomy patients on both the 3rd and 5th postoperative days (p<0.001).

Patients who underwent additional intestinal resection had a significantly higher stoma output. Stoma output of patients without any resection of small intestine showed a significant lower amount on the 3rd postoperative day (p<0.05) and a highly significant lower amount on the 5th postoperative day (p<0.001).

Table 5: Distribution according to stoma output and procedure done

Res. S.I = Resection of small intestine.

On the 3rd postoperative day, out of 42 patients of ileostomy with no resection of small bowel 22 (52.4%) had stoma output less than 500 ml and rest 20 (47.6%) had stoma output between 500-1000 ml with a mean of 476.2±190.9 ml and on the 5th postoperative day out of 41 patients 6 (14.6%) had stoma output less than 500 ml, 33 (80.5%) between 500-1000 ml and 2 (4.9%) more than 1000 ml with a mean output of 670.7±161.2 ml (Tables -4 & 5).

In 16 patients having ileostomy with resection of small bowel, 5 (31.2%) had stoma output less than 500 ml and 11 (68.8%) had stoma output between 500-1000 ml on the 3rd postoperative day with a mean of 525±126.2 ml. On the 5th postoperative day out of 15 patients of ileostomy with resection of small bowel 10 (66.7%) had stoma between 500-1000 ml and 5 (33.3%) had stoma output more than 1000 ml with a mean of 833.3±194.6 ml (Tables -4 & 5).

In 54 patients of stoma with no resection 34 (63%) had stoma output <500 ml and the rest 20 (37%) had stoma output between 500-1000 ml on the 3rd postoperative day. On the 5th postoperative day, of the 53 patients, 18 (34%) had stoma output <500 ml, 33 (62.5%) had stoma output between 500-1000 ml, and 2 (3.5%) had stoma output >1000 ml.

In a total 12 patients of colostomy, the stoma output was less than 500 ml on both the 3rd and 5th postoperative days with a mean of 208.3±90.9 ml on the 3rd and 300±95.7 ml on the 5th postoperative day. (Tables -4 & 5).

Table 6: Various groups of intestinal stoma patients (n=no. of patients)

*2 patients expired, 1 on the 4th day and the other on the 5th post-op. day.

Group (1): All stoma patients containing all ileostomy and colostomy patients (n=70).
Group (2): All ileostomy patients (n=58).
Group (3): Ileostomy patients who underwent additional resection of small bowel (n=16).
Group (4): Stoma (Ileostomy+Colostomy) patients having no resection of small bowel (n=54).
Group (5): All colostomy patients (n=12)
Group (6): Patients having stoma output ³1000 ml on postoperative day 5 (n=7).

SERUM ELECTROLYTES
(i) Serum Sodium:

Table 7: Comparison of serum sodium (in mmol/L) in various groups of intestinal stoma patients (mean±S.D)

(1) In the group having all stoma patients, when postoperative day 1 reading was compared to postoperative day 3 and day 5 readings, a significant lower reading was observed on day 3 (p<0.05) and day 5 (p<0.001). When postoperative day 3 reading was compared with postoperative day 5 reading a significant lower reading was observed on postoperative day 5(p<0.01). [A:B=S, A:C=S, B:C=S; (S=significant, NS=not significant)].

(2) In the group having all ileostomy patients, when postoperative day 1 reading was compared to postoperative day 3 and day 5 readings, a significant lower reading was observed on postoperative day 3 (p<0.05) and day 5 (p<0.001). When postoperative day 3 reading was compared with postoperative day 5 reading a significant lower reading was observed on postoperative day 5(p<0.01). [A:B=S, A:C=S, B:C=S].

(3) In the group having ileostomy with resection of small intestine, when postoperative day 1 reading was compared to postoperative day 3 and day 5 readings, a significant lower value was observed on postoperative day 3 (p<0.05) and day 5 (p<0.001). When postoperative day 3 reading was compared with postoperative day 5 reading a significant lower value was observed on day 5 (p<0.01). [A:B=S, A:C=S, B:C=S].

(4) In the group having stoma with no resection of small intestine no statistically significant change (p>0.05) was observed when postoperative day 1 and day 3 readings were compared. However, a statistically significant lower reading was observed on postoperative day 5 (p<0.05). Changes in serum sodium level between postoperative day 3 and day 5, though lower on postoperative day 5, were not statistically significant. [A:B=NS, A:C=S, B:C=NS].

(5) In the group having colostomy, no significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared to each other. [A:B=NS, A:C=NS, B:C=NS].

(6) In the group having daily stoma output ³1000 ml (on 5th day), no significant change (p>0.05) was noted when postoperative day 1 reading was compared to postoperative day 3 reading. A statistically significant lower value was observed on postoperative day 5 when postoperative day 1 and day 3 readings were compared to the postoperative day 5 reading (p<0.05). [A:B=NS, A:C=S, B:C=S].

In comparison of group (2) ileostomy and group (5) colostomy patients, no significant change (p>0.05) was observed when postoperative day 1 readings were compared. When postoperative day 3 and day 5 readings were compared between groups (2) and (5), the readings in the ileostomy group were found to be significantly lower than in the colostomy group (p<0.001). [A:A=NS, B:B=S, C:C=S].

In comparison of group (3) ileostomy with resection of small intestine and group (4) stoma with no resection of small intestine, no significant change (p>0.05) was observed when postoperative day 1 readings were compared. When postoperative day 3 and day 5 readings were compared between these groups (3 and 4), the reading in group (3) ileostomy with resection of small intestine, were found to be significantly lower than in group (4) (p<0.05). [A:A=NS, B:B=S, C:C=S].

Except for the patients of group (3) ileostomy with resection of ileal segment and (6) stoma patients with output ³1000 ml/day who on the 5th day had a mean serum sodium level below 135 mmol/m on postoperative day 5, all other groups of stoma had mean serum sodium levels in normal range in the postoperative period.

The value of serum sodium ranged from 134-143 mmol/L on postoperative day 1, 132-145 mmol/L on postoperative day 3 and 132-144 mmol/L on postoperative day 5.
Three out of 70 patients on postoperative day 1 and five out of 70 patients on postoperative day 3 had serum sodium values less than 135 mmol/L. On postoperative day 5, 9 out of 68 patients had serum sodium values less than 135 mmol/L. The rest of the patients had values in the normal range of 135-145 mmol/L.

(ii) Serum Potassium:

Table 8: Comparison of serum potassium (in mmol/L) in various groups of intestinal stoma patients (mean±S.D)

(1) In the group having all stoma patients, when postoperative day 1 reading was compared with postoperative day 3 and day 5 reading, a significant lower value was observed, on postoperative day 3 (p<0.05) and day 5(p<0.001). When postoperative day 3 reading was compared with postoperative day 5 reading, there was no significant change (p>0.05) observed. [A:B=S, A:C=S, B:C=NS].

(2) In the group having all ileostomy patients, when postoperative day 1 reading was compared with postoperative day 5 reading, a significant lower value (p<0.05) was observed on postoperative day 5. When postoperative day 3 reading was compared with postoperative day 1 and day 5 readings, no significant change was observed (p>0.05). [A:B=NS, A:C=S, B:C=NS].

(3) In the group having ileostomy with resection of small intestine, when postoperative day 1, reading was compared to postoperative day 3 and day 5 readings, a significant lower value (p<0.05) was observed on postoperative day 3 and day 5. When postoperative day 3 reading was compared with postoperative 5 day reading, no significant change (p>0.05) was observed. [A:B=S, A:C=S, B:C=NS].

(4) In the group having stoma with no resection of small intestine, when postoperative day 1 reading was compared to postoperative day 3 and day 5 readings, postoperative day 3 (p<0.05) and day 5 (p<0.001) readings were found to be significantly lower than day 1. No significant change (p>0.05) was observed when postoperative day 3 reading was compared to postoperative day 5 reading. [A:B=S, A:C=S, B:C=NS].

(5) In the group having colostomy, no significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared to each other. [A:B=NS, A:C=NS, B:C=NS].

(6) In the group having daily stoma output³1000 ml on the 5th postoperative day, when postoperative day 1 reading was compared to postoperative day 5, postoperative day 5 reading was observed to be significantly lower (p<0.05). No significant change (p>0.05) was observed when postoperative day 3 reading was compared to postoperative day 1 and day 5 readings. [A:B=NS, A:C=S, B:C=NS].

In comparison of group (2) ileostomy and group (5) colostomy, no significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared between these groups. [A:A=NS, B:B=NS, C:C=NS].

In comparison of group (3) ileostomy with resection of small intestine and group (4) stoma without resection of small intestine no significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared between these groups. [A:A=NS, B:B=NS, C:C=NS].

The mean values of serum potassium remained within the normal range in the postoperative period in all groups.

The values of serum potassium ranged from 3.4-5.0 mmol/L on postoperative day 1, 3.3-5.2 mmol/L on postoperative day 3 and 3.2-5.0 mmol/L on postoperative day 5.

Two out of 70 stoma patients on postoperative day 1, and four out of 70 patients on postoperative day 3 had serum potassium values less than 3.5 mmol/L. One patient on postoperative day 3 had serum potassium values more than 5.0 mmol/L. Five out of 68 patients on postoperative 5 had serum potassium values less than 3.5 mmol/L. The rest of the patients had serum potassium values in the normal range of 3.5-5.0 mmol/L.

(iii) Serum Calcium:

Table 9: Comparison of serum calcium (in mmol/L) in various groups of intestinal stoma patients (mean±S.D)

No significant change (p>0.05) was observed when postoperative day 1, day 2 and day 3 readings were compared within the groups in the following groups.
(1) Group having all stoma patients [A:B=NS, A:C=NS, B:C=NS].
(2) Group having all ileostomy patients [A:B=NS, A:C=NS, B:C=NS].
(3) Group having ileostomy with resection of small intestine [A:B=NS, A:C=NS, B:C=NS].
(4) Group having stoma patients with no resection of small intestine [A:B=NS, A:C=NS, B:C=NS].
(5) Group having all colostomy patients [A:B=NS, A:C=NS, B:C=NS].
(6) Group having patient with stoma output ³1000 ml on the 5th postoperative day, [A:B=NS, A:C=NS, B:C=NS].

In comparison of postoperative day 1, day 3 and day 5 readings between group (2) ileostomy and group (5) colostomy, no significant change was observed (p>0.05). [A:A=NS, B:B=NS, C:C=NS].

In comparison of group (3) ileostomy with resection of small intestine and group (4) stoma with no resection of small intestine, no significant change was observed (p>0.05) [A:A=NS, B:B=NS, C:C=NS].

The mean values of serum calcium remained within the normal range in the postoperative period in all groups.

The values of serum calcium ranged from 2.12-2.58 mmol/L on postoperative day 1, 1.94-2.57 mmol/L on day 3 and 1.91-2.56 mmol/L on postoperative day 5.
Out of 70 patients, 3 patients developed carpopedal spasm and tetany. (2 on the 4th day and 1 on the 3rd postoperative day). Two of these three patients had serum calcium values less than 2.1 mmol/L on the 3rd and 5th postoperative days. The rest of the patients had serum calcium values to a normal range of 2.1-2.6 mmol/L.

(iv) Serum Magnesium:

Table 10: Comparison of serum magnesium (in mmol/L) in various groups of intestinal stoma patients (mean±S.D)

No significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared within the groups in the following groups:
(1) Group having all stoma patients [A:B=NS, A:C=NS, B:C=NS].
(2) Group having all ileostomy patients [A:B=NS, A:C=NS, B:C=NS].
(3) Group having ileostomy with resection of small intestine [A:B=NS, A:C=NS, B:C=NS].
(4) Group having stoma patients with no resection of small intestine [A:B=NS, A:C=NS, B:C=NS].
(5) Group having all ileostomy patients [A:B=NS, A:C=NS, B:C=NS].
(6) Group having patients with stoma output ³1000 ml on the 5th postoperative day [A:B=NS, A:C=NS, B:C=NS].

No significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared between the following groups: [A:A=NS, B:B=NS, C:C=NS].
- Group (2) ileostomy and group (5) colostomy and.
- Group (3) ileostomy with resection of small intestine and group (4) stoma with no resection of small intestine.

The mean values of serum magnesium remained within the normal range in the postoperative period in all groups. The values of serum magnesium ranged from 0.75-1.23 mmol/L on postoperative day 1, 0.75-1.24 mmol/L on day 3 and 0.75-1.26 mmol/L on day 5. In one patient serum magnesium value was more than 1.25 mmol/L on postoperative day 5. The rest of the patients had serum magnesium value in normal range of 0.75-1.25 mmol/L.

(v) Serum Chloride:

Table 11: Comparison of serum chloride (in mmol/L) in various groups of intestinal stoma patients (mean±S.D)

No significant change (p>0.05) was observed when postoperative day 1, day 3 and day 5 readings were compared within the groups in the following groups: [A:B=NS, A:C=NS, B:C=NS].
(1) Group having all stoma patients.
(4) Group having stoma patients with no resection of small intestine.
(5) Group having colostomy patients.
(6) Group having patients with stoma output ³1000 ml on the 5th postoperative day.

In group (3) having all ileostomy patients, no significant change (p>0.05) was observed when postoperative day 1 reading was compared to postoperative day 3 and day 5 readings. When postoperative day 3 and day 5 readings were compared, the postoperative day 5 reading was found to be significantly lower (p<0.05). [A:B=NS, A:C=NS, B:C=S].

In group (3) having ileostomy with resection of small intestine, no significant change (p>0.05) was observed when the postoperative day 1 reading was compared to the postoperative day 3 reading. Postoperative day 5 reading was found to be significantly lower (p<0.05) when it was compared to postoperative day 1 and 3 readings. [A:B=NS, A:C=S, B:C=S].

In comparison of group (2) ileostomy and group (5) colostomy postoperative day 3 and day 5 readings were found to be significantly lower (p<0.05) in the ileostomy group, but no significant change (p>0.05) was observed when postoperative day 1 reading was compared between these groups. [A:A=NS, B:B=S, C:C=S].

In comparison of group (3) ileostomy with resection of small intestine, and group (4) stoma with no resection of small intestine, postoperative day 1, day 3 and day 5 readings were found to be significantly lower (p<0.05) in group (3) having ileostomy with resection of small intestine. [A:A=S, B:B=S, C:C=S].

The mean values of serum chloride remained within the normal range in the postoperative period in all groups.

The value of serum chloride ranged from 98-107 mmol/L on postoperative day 1, 97-107 mmol/L on day 3 and 97-107 mmol/L on day 5. Two patients had serum chloride values less than 98 mmol/L, one on day 3 and the other on day 5. The rest of the patients had serum chloride values in the normal range of 98-107 mmol/L.

DISCUSSION

The age of the patients in the study was in the range of 13-80 years, with a mean of 33.14 years. Most of the patients in our study (61.5%) were in the 13-35 year age group. the majority of the patients (>90%) underwent stoma creation for perforation peritonitis (Enteric, Tubercular and other causes) (61.6%) and intestinal obstruction (28.6%). There were no cases of Crohn's and ulcerative colitis or diverticulitis.

It is in contrast to the study of G. Swaninger et al 1991, where most of the patients were of Crohn's disease (mean age 41 years) and ulcerative colitis (mean age 38 years) who were operated for ileostomy.

In the study of Thomas L.B et al, 2003, most patients were elderly (above 70 years) and ostomy was created for cancer (33.0%), IBD (21.9%), diverticulitis (14.9%) and only 2.3% for perforation peritonitis. In our study, there were only 7 cases (10%) of malignancy and 43 (61.6%) cases were of the perforation peritonitis, who underwent stoma creation.

Quantity of Daily stoma output in postoperative period:
In the previous studies the volume of daily ileostomy output was reported in the range of 200-500 ml (Welch et al 1936; Brooke 1957; Smiddy et al 1960; Kramer et al, 1962; Kanaghinis et al, 1963). Low volume ileostomy was defined as daily output around 500 ml and high volume ileostomy as a daily volume of a litre or more, by Hill et al 1974, 1975c.

In our study the average stoma volume in ileostomy patients was 489.6(±176.8) ml on the 3rd day and 714.3(±182.9) ml on the 5th postoperative day.

The ileostomy output tended to be unusually profuse if additional ileal resection had to be performed (Nuguid et al, 1961; Hill et al, 1974, 1975). In our study the ileostomy patients in which resection of ileum was done, the mean output on the 3rd postoperative day was 525(±126.2) ml and on the 5th day was 833.3(±194.6) ml and was significantly higher than patients having stomas with no resection of the ileum (p<0.05).

New ileostomy may produce a diarrhoea of 1-2 litre/day as reported by Wright et al, 1973. In this study, 7 (10%) of ileostomy patients had ³1000 ml/day of stoma output on 5th postoperative day; 5 of these 7 patients had ileostomy with ileal resection. The output from colostomy was significant lower than ileostomy and the metabolic changes were mostly confined to the ileostomy patients. Similar results were reported by P.G. Reasbeck et al (1989).

SERUM SODIUM:
The present study revealed a significant decrease in serum sodium concentration postoperatively in patients who underwent stoma creation. Ileostomy patients had significantly lower serum sodium levels compared to colostomy patients on the 3rd and 5th postoperative days (p<0.001).

Ileostomy patients having resection of small intestine had significantly lower serum sodium levels compared to stoma patients with no resection of small bowel on the 3rd and 5th postoperative days (p<0.05). No significant difference was found on postoperative day 1.

The mean value of serum sodium on postoperative day 1, day 3 and day 5 remained within the normal range in all groups of stoma patients except the group having ileostomy with resection of small intestine, and the group of patients having stoma output ³1 litre on postoperative day 5, in which mean serum sodium level decreased below normal on postoperative day 5.

In the group having all stoma patients, there was a decrease in the mean serum sodium level from postoperative day 1 to day 5. The differences between postoperative day 1, day 3 and day 5 were statistically significant (p<0.05).

In the group having all ileostomy patients, there was a decrease in mean serum sodium levels from postoperative day 1 to day 5 which was found to be statistically significant (p<0.05).

In the group having ileostomy with resection of small intestine, there was a decrease in mean serum sodium levels from postoperative day 1 to day 5 reaching below normal range on postoperative day 5 (134.30±1.1 mmol/L). The difference between postoperative day 1 and day 3 was significant and the difference between postoperative day 5 and postoperative day 3(p<0.01) and day 1 was highly significant (p<0.001).

In the group having stoma with no resection of the small bowel, postoperative day 5 values of serum sodium were significantly lower than day 1 values (p<0.05), but no significant difference was found between comparison of other postoperative values.

In the group having colostomy, no significant difference was found in serum sodium values in the postoperative period.

In the group having stoma output ³1000 ml/day on the 5th postoperative day, there was a significantly lower value of mean serum sodium on the 5th postoperative day as compared to postoperative day 1 and day 3. The mean serum sodium value was lower than the normal range on the 5th postoperative day (133.6±1 mmol/L).

The above findings correspond to the works of Hill G-L et al, 1974, Gallagher et al, 1962, Clarke et al, 1967, 1969 who also observed decrease in serum levels in the postoperative period in patients with ileostomy. Nuguid et al, 1961, Wright et al, 1973, Hill et al, 1974, 1975, also observed that resection of ileum with ileostomy increases stoma output and electrolyte losses. P.G. Reasbeck et al, 1989, also observed that metabolic complications are mostly confined to ileostomy patients.

SERUM POTASSIUM:
In our study, no significant change was observed when postoperative day 1, day 3 and day 5 serum potassium values were compared between ileostomy and colostomy patients and between patients having ileostomy with resection of ileum and stoma patients with no resection of ileum.

The mean values of serum potassium of postoperative day 1, day 3 and day 5 remained within the normal range in all groups of stoma patients.

In all the groups of stoma patients, the value of serum potassium decreased slightly from postoperative day 1 to day 5 but remained within the normal range.

Significantly lower serum potassium values of postoperative day 3 and day 5 were observed compared to postoperative day 1 in the groups of all stoma patients, ileostomy patients with resection of small intestine and ileostomy patients with no resection of small bowel (p<0.05). No significant change was observed between postoperative day 3 and day 5 values.

In the groups having all ileostomy patients and patients with stoma output more ³1000 ml on the 5th day, the postoperative day 5 value of serum potassium was found to be significantly lower than the day 1 value (p<0.05). No significant change was found in the postoperative period in the colostomy patients.

This is in agreement with the results documented by various authors L.O Nilsson et al, 1982, Turnberg L.A et al, 1978, J.C. Goligher 1975, who observed a slight decrease in serum potassium levels in ileostomy patients but found no signs of potassium depletion in patients with ileostomy.

However, some other authors have observed an increase in serum potassium level in patients with ileostomy (N.D Gallagher et al, 1962, Swaniger et al, 1991). No such increase was noted in this study.

SERUM CALCIUM:
No significant change was observed when postoperative day 1, day 3 and day 5 serum calcium values were compared between ileostomy and colostomy patients groups and between patients having ileostomy with resection of ileum and patients having stoma with no resection of ileum.

The mean values of serum calcium on postoperative day 1, day 3 and day 5 remained within the normal range in all groups of stoma patients.
No significant change was observed when the postoperative day 1, day 3 and day 5 serum calcium values were compared with each other within the various intestinal stomas groups.

The above findings are similar to work done by Daly, DW 1968; Singer et al, 1973; K.J. Kennedy, Compston et al, 1983 who studied changes in serum levels of calcium in ileostomists and found no significant changes.

During this study three patients of ileostomy developed carpopedal spasm and tetany, but only two had hypocalcemia and the third had normal serum calcium value. Their mean stoma output was 800 ml/day but none had undergone additional resection and this aberration remained unexplained although some workers noticed this rare complication of decreased serum calcium level in high output stomas. (Healton et al, 1967; Daly DW, 1968; Hill GL et al, 1976; Prasad ML et al, 1984).

SERUM MAGNESIUM:
In this study, no significant change was observed when postoperative day 1, day 3 and day 5 serum magnesium values were compared between ileostomy and colostomy patients groups and between patients having ileostomy with resection of ileum and patients having stoma with no resection of ileum.

The mean serum magnesium values on postoperative day 1, day 3 and day 5 remained within the normal range in all groups of stoma patients.

No significant change was observed when the postoperative day 1, day 3 and day 5 serum magnesium values were compared with each other within the various intestinal stomas groups.

The above findings are similar to work done by H.J. Kennedy, Compston et al, 1983; Hill GL et al, 1976; who studied serum magnesium levels in patients with ileostomy and found no significant changes although magnesium depletion occasionally is seen in patients with high volume ileostomies (Heaton et al, 1967; Hill GL et al, 1976; Prasad ML, 1984).

SERUM CHLORIDE:
In our study, significantly lower values of serum chloride on postoperative day 3 and day 5 were found in ileostomy patients groups compared to the colostomy group (p<0.05).

Also, significantly lower serum chloride levels on postoperative day 1, day 3 and day 5 were found in patients having ileostomy with resection of ileum as compared to patients having stoma with no resection of ileum (p<0.05).

The mean serum chloride values of all stoma groups remained within the normal range on postoperative day 1, day 3 and day 5.

No significant changes were found when the postoperative day 1, day 3 and day 5 serum chloride values were compared with each other within the groups of all stoma patients, stoma patients with no resection of small intestine, colostomy patients and patients with stoma output more than 1 litre on the 5th postoperative day.

In the group having all ileostomy patients, postoperative day 5 serum chloride values were found to be significantly lower than postoperative day 3 values (p<0.05).

In the group having ileostomy with resection of small intestine, postoperative day 5 serum chloride value was found to be significantly lower than postoperative day 1 and day 3 values (p<0.05).

These above findings are similar to the work done by Hill G.L, 1967, Clarke et al, 1967, Kramer P, 1966, Pearl RK, Prasad ML et al, 1984, who reported decreased sodium and chloride levels in patients following ileostomy.

Serum electrolytes and their relationship to quantity of stoma output, and resection of small intestine:
The average quantity of postoperative stoma output in patients with ileostomy was significantly higher than the colostomy patients (p<0.05). Significantly lower levels of serum sodium and serum chloride were found on postoperative day 3 and day 5 in patients with ileostomy compared to colostomy patients (p<0.05). In addition, in the ileostomy group, a significant decrease in levels of serum sodium, serum potassium and chloride occurred in the postoperative period but usually remained within the normal range.

The average quantity of postoperative stoma output was significantly higher in patients having ileostomy with resection of small intestine, compared to stoma patients with no resection of small intestine (p<0.05). Significantly lower levels of serum sodium and chloride were observed postoperatively in patients having ileostomy with resection of small intestine compared to stoma patients with no resection of small intestine (p<0.05). In addition, in the group having ileostomy with resection of small intestine, a significant decrease in levels of serum sodium, serum potassium and serum chloride was observed in the postoperative period but their levels remained in normal range, except for serum sodium which was below normal on postoperative day 5.

The above observations must be viewed in the context that these intestinal stomas patients were receiving intravenous fluid and electrolytes till the 3rd day postoperatively. It may, however be noted that no patient was allowed to go into a fluid deficit.

Serum electrolytes losses in patients following creation of intestinal stomas have been reported by several workers. (Gallagher et al, 1962; Kramer P, 1966; Clarke et al, 1967; Hill GL, 1967; LO Nilsson et al, 1982; Pearl RK, Prasad ML et al, 1984; G. Swaninger et al, 1991).

These losses if not adequately replaced, may lead to electrolyte deficient status. The findings in the present study are similar to the previously reported findings. Since the study of serum electrolytes in the stoma effluent was not done in this study, relationships showing the quantitative loss of electrolytes and serum electrolytes concentrations was not possible.

CONCLUSION

The stoma output was found to be higher in patients having ileostomy and was significantly higher in patients who had additional ileal segment resection done.

Serum sodium and serum chloride levels in patients with ileostomy, especially ileostomy with additional resection of ileal segment, showed a significant decrease in serum sodium and serum chloride levels on all days in the postoperative period as compared to patients with no resection of ileum or those undergoing colostomy.

Serum potassium level showed a significant decrease in patients with ileostomy, especially those having additional resection of ileal segment in the postoperative period, on the 5th postoperative day.

Serum calcium and serum magnesium concentration showed no significant change in the postoperative period in all groups of patients.

The patients with colostomy showed no significant change in serum electrolyte concentrations in postoperative period.

In the group of patients, having high output ileostomy (³ 1 litre/day), there was a significant decrease in serum sodium and serum potassium on the 5th postoperative day.

The mean serum sodium level remained within the normal range on postoperative day 1, day 3 and day 5 in all groups of stoma patients, except in patients having ileostomy with additional resection of ileal segment and patients with high ileostomy output (i.e. ³ 1 litre per day), in which serum sodium level decreased below normal range by the 5th postoperative day.

The serum levels of potassium, calcium, magnesium and chloride remained within normal range in the postoperative period in all groups of stoma patients.

From this study, it can be concluded that:
1. Patients undergoing colostomy have low stoma output i.e. below 500 ml/day;they do not develop fluid or electrolyte derangements in the early postoperative period and need no monitoring.
2. Patients undergoing ileostomy have average stoma output higher than colostomy patients i.e. around 500-600 ml/day; all these patients showed a fall in electrolyte values in the early postoperative period but the mean values tend to remain in the normal range.
3. Patients who underwent ileal resection in addition to ileostomy, have a significantly higher stoma output. These patients showed a significant fall in serum electrolyte levels, especially of sodium, chloride and potassium. Serum sodium values fell below normal range by the 5th postoperative day.
4. Patients with high output stomas (>1000 ml/day) developed significant derangement of serum electrolytes namely sodium and potassium.

In conclusion on the basis of this study, it is recommended that:
-In all ileostomy patients, serum electrolytes should be routinely estimated on the fifth postoperative day.
- In all patients who undergo ileal resection along with ileostomy or who have high ileostomy output, should be closely monitored for electrolyte derangements from the third postoperative day onwards.
-No definite regimen of serum electrolytes replacement can be recommended. Replacements of fluids and electrolytes have to be individually tailored based on postoperative serum electrolyte monitoring.

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